@article{taitingfong_triplett_vasquez_rajagopalan_raban_roberts_terradas_baumgartner_emerson_gould_et al._2022, title={Exploring the value of a global gene drive project registry}, volume={12}, ISSN={["1546-1696"]}, DOI={10.1038/s41587-022-01591-w}, journal={NATURE BIOTECHNOLOGY}, author={Taitingfong, Riley I. and Triplett, Cynthia and Vasquez, Valeri N. and Rajagopalan, Ramya M. and Raban, Robyn and Roberts, Aaron and Terradas, Gerard and Baumgartner, Bridget and Emerson, Claudia and Gould, Fred and et al.}, year={2022}, month={Dec} }
 @article{resnik_medina_gould_church_kuzma_2022, title={Genes drive organisms and slippery slopes}, volume={12}, ISSN={["2047-7732"]}, DOI={10.1080/20477724.2022.2160895}, abstractNote={The bioethical debate about using gene drives to alter or eradicate wild populations has focused mostly on issues concerning short-term risk assessment and management, governance and oversight, and public and community engagement, but has not examined big-picture- 'where is this going?'-questions in great depth. In other areas of bioethical controversy, big-picture questions often enter the public forum via slippery slope arguments. Given the incredible potential of gene drive organisms to alter the Earth's biota, it is somewhat surprising that slippery slope arguments have not played a more prominent role in ethical and policy debates about these emerging technologies. In this article, we examine a type of slippery slope argument against using gene drives to alter or suppress wild pest populations and consider whether it has a role to play in ethical and policy debates. Although we conclude that this argument does not provide compelling reasons for banning the use of gene drives in wild pest populations, we believe that it still has value as a morally instructive cautionary narrative that can motivate scientists, ethicists, and members of the public to think more clearly about appropriate vs. inappropriate uses of gene drive technologies, the long-term and cumulative and emergent risks of using gene drives in wild populations, and steps that can be taken to manage these risks, such as protecting wilderness areas where people can enjoy life forms that have not been genetically engineered.}, journal={PATHOGENS AND GLOBAL HEALTH}, author={Resnik, David B. and Medina, Raul F. and Gould, Fred and Church, George and Kuzma, Jennifer}, year={2022}, month={Dec} }
 @article{dhammi_krestchmar_zhu_ponnusamy_gould_reisig_kurtz_roe_2022, title={Impact of Caterpillar Increased Feeding Rates on Reduction of Bt Susceptibility}, volume={23}, ISSN={["1422-0067"]}, url={https://www.mdpi.com/1422-0067/23/23/14856}, DOI={10.3390/ijms232314856}, abstractNote={The use of insect-resistant transgenic crops producing Bacillus thuringiensis protein Cry toxins (Bt) to control caterpillars is wide-spread. Development of a mechanism to prevent Bt from reaching its target site in the digestive system could result in Bt resistance and resistance to other insecticides active per os. Increased feeding rates by increasing temperature in tobacco budworms, Chloridea virescens, and bollworms, Helicoverpa zea, decreased Bt Cry1Ac susceptibility and mortality. The same was found in C. virescens for Bollgard II plant extract containing Bt Cry1Ac and Cry2Ab2 toxins. Furthermore, H. zea from the same inbred laboratory colony that fed faster independent of temperature manipulation were less susceptible to Bt intoxication. A laboratory derived C. virescens Bt resistant strain demonstrated a higher feeding rate on non-Bt artificial diet than the parental, Bt susceptible strain. A laboratory-reared Bt resistant fall armyworm, Spodoptera frugiperda, strain also fed faster on non-Bt diet compared to Bt susceptible caterpillars of the same species, both originally collected from corn. The studies in toto and the literature reviewed support the hypothesis that increased feeding rate is a behavioral mechanism for reducing caterpillar susceptibility to Bt. Its possible role in resistance needs further study.}, number={23}, journal={INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES}, author={Dhammi, Anirudh and Krestchmar, Jaap B. and Zhu, Jiwei and Ponnusamy, Loganathan and Gould, Fred and Reisig, Dominic and Kurtz, Ryan W. and Roe, R. Michael}, year={2022}, month={Dec} }
 @article{taylor_hamby_deyonke_gould_fritz_2021, title={Genome evolution in an agricultural pest following adoption of transgenic crops}, volume={118}, ISSN={["1091-6490"]}, DOI={10.1073/pnas.2020853118}, abstractNote={Replacing synthetic insecticides with transgenic crops for pest management has been economically and environmentally beneficial, but these benefits erode as pests evolve resistance. It has been proposed that novel genomic approaches could track molecular signals of emerging resistance to aid in resistance management. To test this, we quantified patterns of genomic change in Helicoverpa zea, a major lepidopteran pest and target of transgenic Bacillus thuringiensis (Bt) crops, between 2002 and 2017 as both Bt crop adoption and resistance increased in North America. Genomic scans of wild H. zea were paired with quantitative trait locus (QTL) analyses and showed the genomic architecture of field-evolved Cry1Ab resistance was polygenic, likely arising from standing genetic variation. Resistance to pyramided Cry1A.105 and Cry2Ab2 toxins was controlled by fewer loci. Of the 11 previously described Bt resistance genes, 9 showed no significant change over time or major effects on resistance. We were unable to rule out a contribution of aminopeptidases (apns), as a cluster of apn genes were found within a Cry-associated QTL. Molecular signals of emerging Bt resistance were detectable as early as 2012 in our samples, and we discuss the potential and pitfalls of whole-genome analysis for resistance monitoring based on our findings. This first study of Bt resistance evolution using whole-genome analysis of field-collected specimens demonstrates the need for a more holistic approach to examining rapid adaptation to novel selection pressures in agricultural ecosystems.}, number={52}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Taylor, Katherine L. and Hamby, Kelly A. and DeYonke, Alexandra M. and Gould, Fred and Fritz, Megan L.}, year={2021}, month={Dec} }
 @article{vella_gould_lloyd_2021, title={Mathematical modeling of genetic pest management through female-specific lethality: Is one locus better than two?}, volume={14}, ISSN={["1752-4571"]}, url={https://doi.org/10.1111/eva.13228}, DOI={10.1111/eva.13228}, abstractNote={Many novel genetic approaches are under development to combat insect pests. One genetic strategy aims to suppress or locally eliminate a species through large, repeated releases of genetically engineered strains that render female offspring unviable under field conditions. Strains with this female-killing characteristic have been developed either with all of the molecular components in a single construct or with the components in two constructs inserted at independently assorting loci. Strains with two constructs are typically considered to be only of value as research tools and for producing solely male offspring in rearing factories which are subsequently sterilized by radiation before release. A concern with the two-construct strains is that once released, the two constructs would become separated and therefore non-functional. The only female-killing strains that have been released in the field without sterilization are single-construct strains. Here, we use a population genetics model with density dependence to evaluate the relative effectiveness of female-killing approaches based on single- and two-construct arrangements. We find that, in general, the single-construct arrangement results in slightly faster population suppression, but the two-construct arrangement can eventually cause stronger suppression and cause local elimination with a smaller release size. Based on our results, there is no a priori reason that males carrying two independently segregating constructs need to be sterilized prior to release. In some cases, a fertile release would be more efficient for population suppression.}, number={6}, journal={EVOLUTIONARY APPLICATIONS}, publisher={Wiley}, author={Vella, Michael R. and Gould, Fred and Lloyd, Alun L.}, year={2021}, month={Jun}, pages={1612–1622} }
 @article{oh_shiels_shiels_blondel_campbell_saah_lloyd_thomas_gould_abdo_et al._2021, title={Population genomics of invasive rodents on islands: Genetic consequences of colonization and prospects for localized synthetic gene drive}, volume={14}, ISSN={["1752-4571"]}, DOI={10.1111/eva.13210}, abstractNote={Introduced rodent populations pose significant threats worldwide, with particularly severe impacts on islands. Advancements in genome editing have motivated interest in synthetic gene drives that could potentially provide efficient and localized suppression of invasive rodent populations. Application of such technologies will require rigorous population genomic surveys to evaluate population connectivity, taxonomic identification, and to inform design of gene drive localization mechanisms. One proposed approach leverages the predicted shifts in genetic variation that accompany island colonization, wherein founder effects, genetic drift, and island-specific selection are expected to result in locally fixed alleles (LFA) that are variable in neighboring nontarget populations. Engineering of guide RNAs that target LFA may thus yield gene drives that spread within invasive island populations, but would have limited impacts on nontarget populations in the event of an escape. Here we used pooled whole-genome sequencing of invasive mouse (Mus musculus) populations on four islands along with paired putative source populations to test genetic predictions of island colonization and characterize locally fixed Cas9 genomic targets. Patterns of variation across the genome reflected marked reductions in allelic diversity in island populations and moderate to high degrees of differentiation from nearby source populations despite relatively recent colonization. Locally fixed Cas9 sites in female fertility genes were observed in all island populations, including a small number with multiplexing potential. In practice, rigorous sampling of presumptive LFA will be essential to fully assess risk of resistance alleles. These results should serve to guide development of improved, spatially limited gene drive design in future applications.}, number={5}, journal={EVOLUTIONARY APPLICATIONS}, author={Oh, Kevin P. and Shiels, Aaron B. and Shiels, Laura and Blondel, Dimitri V and Campbell, Karl J. and Saah, J. Royden and Lloyd, Alun L. and Thomas, Paul Q. and Gould, Fred and Abdo, Zaid and et al.}, year={2021}, month={May}, pages={1421–1435} }
 @article{baltzegar_vella_gunning_vasquez_astete_stell_fisher_scott_lenhart_lloyd_et al._2021, title={Rapid evolution of knockdown resistance haplotypes in response to pyrethroid selection in Aedes aegypti}, volume={7}, ISSN={["1752-4571"]}, DOI={10.1111/eva.13269}, abstractNote={This study describes the evolution of knockdown resistance (kdr) haplotypes in Aedes aegypti in response to pyrethroid insecticide use over the course of 18 years in Iquitos, Peru. Based on the duration and intensiveness of sampling (~10,000 samples), this is the most thorough study of kdr population genetics in Ae. aegypti to date within a city. We provide evidence for the direct connection between programmatic citywide pyrethroid spraying and the increase in frequency of specific kdr haplotypes by identifying two evolutionary events in the population. The relatively high selection coefficients, even under infrequent insecticide pressure, emphasize how quickly Ae. aegypti populations can evolve. In our examination of the literature on mosquitoes and other insect pests, we could find no cases where a pest evolved so quickly to so few exposures to low or nonresidual insecticide applications. The observed rapid increase in frequency of resistance alleles might have been aided by the incomplete dominance of resistance-conferring alleles over corresponding susceptibility alleles. In addition to dramatic temporal shifts, spatial suppression experiments reveal that genetic heterogeneity existed not only at the citywide scale, but also on a very fine scale within the city.}, journal={EVOLUTIONARY APPLICATIONS}, author={Baltzegar, Jennifer and Vella, Michael and Gunning, Christian and Vasquez, Gissella and Astete, Helvio and Stell, Fred and Fisher, Michael and Scott, Thomas W. and Lenhart, Audrey and Lloyd, Alun L. and et al.}, year={2021}, month={Jul} }
 @article{dhole_lloyd_gould_2020, title={Gene Drive Dynamics in Natural Populations: The Importance of Density Dependence, Space, and Sex}, volume={51}, ISSN={["1545-2069"]}, DOI={10.1146/annurev-ecolsys-031120-101013}, abstractNote={The spread of synthetic gene drives is often discussed in the context of panmictic populations connected by gene flow and described with simple deterministic models. Under such assumptions, an entire species could be altered by releasing a single individual carrying an invasive gene drive, such as a standard homing drive. While this remains a theoretical possibility, gene drive spread in natural populations is more complex and merits a more realistic assessment. The fate of any gene drive released in a population would be inextricably linked to the ecology of the population. Given the uncertainty often involved in ecological assessment of natural populations, understanding the sensitivity of gene drive spread to important ecological factors is critical. Here we review how different forms of density-dependence, spatial heterogeneity and mating behaviors can impact the spread of self-sustaining gene drives. We highlight specific aspects of gene drive dynamics and the target populations that need further research.}, number={1}, journal={ANNUAL REVIEW OF ECOLOGY, EVOLUTION, AND SYSTEMATICS, VOL 51, 2020}, author={Dhole, Sumit and Lloyd, Alun L. and Gould, Fred}, year={2020}, pages={505–531} }
 @article{rice_schoen_aristidou_burgess_capalbo_czarnecki-maulden_dunham_ejeta_famigilietti_gould_et al._2020, title={Keeping up with the fast-moving world of crisis management}, volume={37}, ISSN={["1572-8366"]}, DOI={10.1007/s10460-020-10045-5}, abstractNote={Author(s): Rice, Charles W; Schoen, Robin; Aristidou, Aristos; Burgess, Shane C; Capalbo, Susan; Czarnecki-Maulden, Gail; Dunham, Bernadette; Ejeta, Gibesa; Famigilietti, Jay S; Gould, Fred; Hamer, John; Jackson-Smith, Douglas B; Jones, James W; Kebreab, Ermias; Kelley, Stephen S; Leach, Jan E; Lougee, Robin; McCluskey, Jill J; Plaut, Karen I; Salvador, Ricardo J; Sample, V Alaric}, number={3}, journal={AGRICULTURE AND HUMAN VALUES}, author={Rice, Charles W. and Schoen, Robin and Aristidou, Aristos and Burgess, Shane C. and Capalbo, Susan and Czarnecki-Maulden, Gail and Dunham, Bernadette and Ejeta, Gibesa and Famigilietti, Jay S. and Gould, Fred and et al.}, year={2020}, month={Sep}, pages={531–533} }
 @article{cash_robert_lorenzen_gould_2020, title={The impact of local population genetic background on the spread of the selfish element Medea-1 in red flour beetles}, volume={10}, ISSN={["2045-7758"]}, DOI={10.1002/ece3.5946}, abstractNote={Selfish genetic elements have been found in the genomes of many species, yet our understanding of their evolutionary dynamics is only partially understood. A number of distinct selfish Medea elements are naturally present in many populations of the red flour beetle (Tribolium castaneum). Although these Medea elements are predicted by models to increase in frequency within populations because any offspring of a Medea-bearing mother that do not inherit at least one Medea allele will die, experiments demonstrating an increase in a naturally occurring Medea element are lacking. Our survey of the specific Medea element, M1, in the United States showed that it had a patchy geographic distribution. From the survey, it could not be determined if this distribution was caused by a slow process of M1 colonization of discrete populations or if some populations lacked M1 because they had genetic factors conferring resistance to the Medea mechanism. We show that populations with naturally low to intermediate M1 frequencies likely represent transient states during the process of Medea spread. Furthermore, we find no evidence that genetic factors are excluding M1 from US populations where the element is not presently found. We also show how a known suppressor of Medea can impair the increase of M1 in populations and discuss the implications of our findings for pest-management applications of Medea elements.}, number={2}, journal={ECOLOGY AND EVOLUTION}, author={Cash, Sarah A. and Robert, Michael A. and Lorenzen, Marce D. and Gould, Fred}, year={2020}, month={Jan}, pages={863–874} }
 @article{pixley_falck-zepeda_giller_glenna_gould_mallory-smith_stelly_stewart_2019, title={Genome Editing, Gene Drives, and Synthetic Biology: Will They Contribute to Disease-Resistant Crops, and Who Will Benefit?}, volume={57}, ISSN={["1545-2107"]}, DOI={10.1146/annurev-phyto-080417-045954}, abstractNote={Genetically engineered crops have been grown for more than 20 years, resulting in widespread albeit variable benefits for farmers and consumers. We review current, likely, and potential genetic engineering (GE) applications for the development of disease-resistant crop cultivars. Gene editing, gene drives, and synthetic biology offer novel opportunities to control viral, bacterial, and fungal pathogens, parasitic weeds, and insect vectors of plant pathogens. We conclude that there will be no shortage of GE applications to tackle disease resistance and other farmer and consumer priorities for agricultural crops. Beyond reviewing scientific prospects for genetically engineered crops, we address the social institutional forces that are commonly overlooked by biological scientists. Intellectual property regimes, technology regulatory frameworks, the balance of funding between public- and private-sector research, and advocacy by concerned civil society groups interact to define who uses which GE technologies, on which crops, and for the benefit of whom. Ensuring equitable access to the benefits of genetically engineered crops requires affirmative policies, targeted investments, and excellent science.}, journal={ANNUAL REVIEW OF PHYTOPATHOLOGY, VOL 57, 2019}, author={Pixley, Kevin V. and Falck-Zepeda, Jose B. and Giller, Ken E. and Glenna, Leland L. and Gould, Fred and Mallory-Smith, Carol A. and Stelly, David M. and Stewart, C. Neal, Jr.}, year={2019}, pages={165–188} }
 @article{sudweeks_hollingsworth_blondel_campbell_dhole_eisemann_edwards_godwin_howald_oh_et al._2019, title={Locally Fixed Alleles: A method to localize gene drive to island populations}, volume={9}, ISSN={["2045-2322"]}, DOI={10.1038/s41598-019-51994-0}, abstractNote={Abstract Invasive species pose a major threat to biodiversity on islands. While successes have been achieved using traditional removal methods, such as toxicants aimed at rodents, these approaches have limitations and various off-target effects on island ecosystems. Gene drive technologies designed to eliminate a population provide an alternative approach, but the potential for drive-bearing individuals to escape from the target release area and impact populations elsewhere is a major concern. Here we propose the “Locally Fixed Alleles” approach as a novel means for localizing elimination by a drive to an island population that exhibits significant genetic isolation from neighboring populations. Our approach is based on the assumption that in small island populations of rodents, genetic drift will lead to alleles at multiple genomic loci becoming fixed. In contrast, multiple alleles are likely to be maintained in larger populations on mainlands. Utilizing the high degree of genetic specificity achievable using homing drives, for example based on the CRISPR/Cas9 system, our approach aims at employing one or more locally fixed alleles as the target for a gene drive on a particular island. Using mathematical modeling, we explore the feasibility of this approach and the degree of localization that can be achieved. We show that across a wide range of parameter values, escape of the drive to a neighboring population in which the target allele is not fixed will at most lead to modest transient suppression of the non-target population. While the main focus of this paper is on elimination of a rodent pest from an island, we also discuss the utility of the locally fixed allele approach for the goals of population suppression or population replacement. Our analysis also provides a threshold condition for the ability of a gene drive to invade a partially resistant population.}, journal={SCIENTIFIC REPORTS}, author={Sudweeks, Jaye and Hollingsworth, Brandon and Blondel, Dimitri V and Campbell, Karl J. and Dhole, Sumit and Eisemann, John D. and Edwards, Owain and Godwin, John and Howald, Gregg R. and Oh, Kevin P. and et al.}, year={2019}, month={Nov} }
 @article{gould_dhole_lloyd_2019, title={Pest management by genetic addiction}, volume={116}, ISSN={["0027-8424"]}, url={http://dx.doi.org/10.1073/pnas.1901886116}, DOI={10.1073/pnas.1901886116}, abstractNote={In the PNAS article “Cleave and Rescue, a novel selfish genetic element and general strategy for gene drive,” Oberhofer et al. (1) describe an exciting new mechanism for enabling a transgenic sequence to increase in frequency within a sexually reproducing population, even if the transgenic sequence causes individuals bearing it to have somewhat lower fitness than those without it. The authors liken the mechanism to the “gene addiction” that can maintain a useless plasmid in a bacterium. The work of Oberhofer et al. (1) adds substantially to a growing field within genetic engineering, often termed gene drive research, in which selfish genetic elements overcome the rules of Mendelian inheritance and push transgenes into a population. While no engineered gene drives have been released into wild populations, that is the ultimate goal, and both the technical and cultural roads toward that goal have been tortuous at times.

Gene drive projects are categorized based on having one of two aims. The first is to physically link a desirable gene to a gene drive mechanism and engineer both into a viable strain of the target organism. If individuals of the strain are released into a sexually reproducing field population of that species, the DNA sequence of the drive mechanism is predicted to increase in frequency in the population and the linked, desirable gene should “hitchhike” along with it. If the population is a mosquito that transmits dengue virus, the desirable gene could be one that codes for an RNA interference molecule targeted to prevent the virus from replicating in the mosquito—thus interfering with its transmission to a person whom the mosquito subsequently bites.

Projects with the second aim are designed to suppress or eliminate a pest species, be it a mosquito, rat, roach, or crop pest. Here, the gene drive mechanism itself or … 

[↵][1]1To whom correspondence should be addressed. Email: fred_gould{at}ncsu.edu.

 [1]: #xref-corresp-1-1}, number={13}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Gould, Fred and Dhole, Sumit and Lloyd, Alun L.}, year={2019}, month={Mar}, pages={5849–5851} }
 @article{brossard_belluck_gould_wirz_2019, title={Promises and perils of gene drives: Navigating the communication of complex, post-normal science}, volume={116}, ISSN={["0027-8424"]}, DOI={10.1073/pnas.1805874115}, abstractNote={In November of 2017, an interdisciplinary panel discussed the complexities of gene drive applications as part of the third Sackler Colloquium on “The Science of Science Communication.” The panel brought together a social scientist, life scientist, and journalist to discuss the issue from each of their unique perspectives. This paper builds on the ideas and conversations from the session to provide a more nuanced discussion about the context surrounding responsible communication and decision-making for cases of post-normal science. Deciding to use gene drives to control and suppress pests will involve more than a technical assessment of the risks involved, and responsible decision-making regarding their use will require concerted efforts from multiple actors. We provide a review of gene drives and their potential applications, as well as the role of journalists in communicating the extent of uncertainties around specific projects. We also discuss the roles of public opinion and online environments in public engagement with scientific processes. We conclude with specific recommendations about how to address current challenges and foster more effective communication and decision-making for complex, post-normal issues, such as gene drives.}, number={16}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Brossard, Dominique and Belluck, Pam and Gould, Fred and Wirz, Christopher D.}, year={2019}, month={Apr}, pages={7692–7697} }
 @book{allison_brown_goddard_guerinot_jansson_jaykus_jensen_khosla_lougee_lowry_et al._2019, title={Science Breakthroughs to Advance Food and Agricultural Research by 2030}, DOI={10.17226/25059}, journal={SCIENCE BREAKTHROUGHS TO ADVANCE FOOD AND AGRICULTURAL RESEARCH BY 2030}, author={Allison, David B. and Brown, Corrie C. and Goddard, Lisa M. and Guerinot, Mary Lou and Jansson, Janet K. and Jaykus, Lee-Ann and Jensen, Helen H. and Khosla, Rajiv and Lougee, Robin and Lowry, Gregory V. and et al.}, year={2019}, pages={1–228} }
 @article{dhole_lloyd_gould_2019, title={Tethered homing gene drives: A new design for spatially restricted population replacement and suppression}, volume={12}, ISSN={["1752-4571"]}, url={http://dx.doi.org/10.1111/eva.12827}, DOI={10.1111/eva.12827}, abstractNote={Optimism regarding potential epidemiological and conservation applications of modern gene drives is tempered by concern about the possibility of unintended spread of engineered organisms beyond the target population. In response, several novel gene drive approaches have been proposed that can, under certain conditions, locally alter characteristics of a population. One challenge for these gene drives is the difficulty of achieving high levels of localized population suppression without very large releases in the face of gene flow. We present a new gene drive system, tethered homing (TH), with improved capacity for both localization and population suppression. The TH drive is based on driving a payload gene using a homing construct that is anchored to a spatially restricted gene drive. We use a proof-of-concept mathematical model to show the dynamics of a TH drive that uses engineered underdominance as an anchor. This system is composed of a split homing drive and a two-locus engineered underdominance drive linked to one part of the split drive (the Cas endonuclease). We use simple population genetic simulations to show that the tethered homing technique can offer improved localized spread of costly transgenic payload genes. Additionally, the TH system offers the ability to gradually adjust the genetic load in a population after the initial alteration, with minimal additional release effort. We discuss potential solutions for improving localization and the feasibility of creating TH drive systems. Further research with models that include additional biological details will be needed to better understand how TH drives would behave in natural populations, but the preliminary results shown here suggest that tethered homing drives can be a useful addition to the repertoire of localized gene drives.}, number={8}, journal={EVOLUTIONARY APPLICATIONS}, author={Dhole, Sumit and Lloyd, Alun L. and Gould, Fred}, year={2019}, month={Sep}, pages={1688–1702} }
 @article{cash_lorenzen_gould_2019, title={The distribution and spread of naturally occurring Medea selfish genetic elements in the United States}, volume={9}, ISSN={["2045-7758"]}, DOI={10.1002/ece3.5876}, abstractNote={Selfish genetic elements (SGEs) are DNA sequences that are transmitted to viable offspring in greater than Mendelian frequencies. Medea SGEs occur naturally in some populations of red flour beetle (Tribolium castaneum) and are expected to increase in frequency within populations and spread among populations. The large-scale U.S. distributions of Medea-4 (M4) had been mapped based on samples from 1993 to 1995. We sampled beetles in 2011-2014 and show that the distribution of M4 in the United States is dynamic and has shifted southward. By using a genetic marker of Medea-1 (M1), we found five unique geographic clusters with high and low M1 frequencies in a pattern not predicted by microsatellite-based analysis of population structure. Our results indicate the absence of rigid barriers to Medea spread in the United States, so assessment of what factors have limited its current distribution requires further investigation. There is great interest in using synthetic SGEs, including synthetic Medea, to alter or suppress pest populations, but there is concern about unpredicted spread of these SGEs and potential for populations to become resistant to them. The finding of patchy distributions of Medea elements suggests that released synthetic SGEs cannot always be expected to spread uniformly, especially in target species with limited dispersal.}, number={24}, journal={ECOLOGY AND EVOLUTION}, author={Cash, Sarah A. and Lorenzen, Marce D. and Gould, Fred}, year={2019}, month={Dec}, pages={14407–14416} }
 @article{kuzma_gould_brown_collins_delborne_frow_esvelt_guston_leitschuh_oye_et al._2018, title={A roadmap for gene drives: using institutional analysis and development to frame research needs and governance in a systems context}, volume={5}, ISSN={2329-9460 2329-9037}, url={http://dx.doi.org/10.1080/23299460.2017.1410344}, DOI={10.1080/23299460.2017.1410344}, abstractNote={ABSTRACTThe deployment of gene drives is emerging as an alternative for protecting endangered species, controlling agricultural pests, and reducing vector-borne diseases. This paper reports on a workshop held in February 2016 to explore the complex intersection of political, economic, ethical, and ecological risk issues associated with gene drives. Workshop participants were encouraged to use systems thinking and mapping to describe the connections among social, policy, economic, and ecological variables as they intersect within governance systems. In this paper, we analyze the workshop transcripts and maps using the Institutional Analysis and Development (IAD) framework to categorize variables associated with gene drive governance and account for the complexities of socio-ecological systems. We discuss how the IAD framework can be used in the future to test hypotheses about how features of governance systems might lead to certain outcomes and inform the design of research programs, public engagement, and...}, number={S1}, journal={Journal of Responsible Innovation}, publisher={Taylor & Francis}, author={Kuzma, J. and Gould, F. and Brown, Z. and Collins, J. and Delborne, J. and Frow, E. and Esvelt, K. and Guston, D. and Leitschuh, C. and Oye, K. and et al.}, year={2018}, pages={S13–S39} }
 @article{fritz_deyonke_papanicolaou_micinski_westbrook_gould_2018, title={Contemporary evolution of a Lepidopteran species, Heliothis virescens, in response to modern agricultural practices}, volume={27}, ISSN={["1365-294X"]}, DOI={10.1111/mec.14430}, abstractNote={Adaptation to human-induced environmental change has the potential to profoundly influence the genomic architecture of affected species. This is particularly true in agricultural ecosystems, where anthropogenic selection pressure is strong. Heliothis virescens primarily feeds on cotton in its larval stages, and US populations have been declining since the widespread planting of transgenic cotton, which endogenously expresses proteins derived from Bacillus thuringiensis (Bt). No physiological adaptation to Bt toxin has been found in the field, so adaptation in this altered environment could involve (i) shifts in host plant selection mechanisms to avoid cotton, (ii) changes in detoxification mechanisms required for cotton-feeding vs. feeding on other hosts or (iii) loss of resistance to previously used management practices including insecticides. Here, we begin to address whether such changes occurred in H. virescens populations between 1997 and 2012, as Bt-cotton cultivation spread through the agricultural landscape. For our study, we produced an H. virescens genome assembly and used this in concert with a ddRAD-seq-enabled genome scan to identify loci with significant allele frequency changes over the 15-year period. Genetic changes at a previously described H. virescens insecticide target of selection were detectable in our genome scan and increased our confidence in this methodology. Additional loci were also detected as being under selection, and we quantified the selection strength required to elicit observed allele frequency changes at each locus. Potential contributions of genes near loci under selection to adaptive phenotypes in the H. virescens cotton system are discussed.}, number={1}, journal={MOLECULAR ECOLOGY}, author={Fritz, Megan L. and DeYonke, Alexandra M. and Papanicolaou, Alexie and Micinski, Stephen and Westbrook, John and Gould, Fred}, year={2018}, month={Jan}, pages={167–181} }
 @article{gunning_okamoto_astete_vasquez_erhardt_del aguila_pinedo_cardenas_pacheco_chalco_et al._2018, title={Efficacy of Aedes aegypti control by indoor Ultra Low Volume (ULV) insecticide spraying in Iquitos, Peru}, volume={12}, ISSN={1935-2735}, url={http://dx.doi.org/10.1371/journal.pntd.0006378}, DOI={10.1371/journal.pntd.0006378}, abstractNote={Background Aedes aegypti is a primary vector of dengue, chikungunya, Zika, and urban yellow fever viruses. Indoor, ultra low volume (ULV) space spraying with pyrethroid insecticides is the main approach used for Ae. aegypti emergency control in many countries. Given the widespread use of this method, the lack of large-scale experiments or detailed evaluations of municipal spray programs is problematic. Methodology/Principal findings Two experimental evaluations of non-residual, indoor ULV pyrethroid spraying were conducted in Iquitos, Peru. In each, a central sprayed sector was surrounded by an unsprayed buffer sector. In 2013, spray and buffer sectors included 398 and 765 houses, respectively. Spraying reduced the mean number of adults captured per house by ~83 percent relative to the pre-spray baseline survey. In the 2014 experiment, sprayed and buffer sectors included 1,117 and 1,049 houses, respectively. Here, the sprayed sector’s number of adults per house was reduced ~64 percent relative to baseline. Parity surveys in the sprayed sector during the 2014 spray period indicated an increase in the proportion of very young females. We also evaluated impacts of a 2014 citywide spray program by the local Ministry of Health, which reduced adult populations by ~60 percent. In all cases, adult densities returned to near-baseline levels within one month. Conclusions/Significance Our results demonstrate that densities of adult Ae. aegypti can be reduced by experimental and municipal spraying programs. The finding that adult densities return to approximately pre-spray densities in less than a month is similar to results from previous, smaller scale experiments. Our results demonstrate that ULV spraying is best viewed as having a short-term entomological effect. The epidemiological impact of ULV spraying will need evaluation in future trials that measure capacity of insecticide spraying to reduce human infection or disease.}, number={4}, journal={PLOS Neglected Tropical Diseases}, publisher={Public Library of Science (PLoS)}, author={Gunning, Christian E. and Okamoto, Kenichi W. and Astete, Helvio and Vasquez, Gissella M. and Erhardt, Erik and Del Aguila, Clara and Pinedo, Raul and Cardenas, Roldan and Pacheco, Carlos and Chalco, Enrique and et al.}, editor={Barrera, RobertoEditor}, year={2018}, month={Apr}, pages={e0006378} }
 @article{dhole_vella_lloyd_gould_2018, title={Invasion and migration of spatially self-limiting gene drives: A comparative analysis}, volume={11}, ISSN={1752-4571}, url={http://dx.doi.org/10.1111/eva.12583}, DOI={10.1111/eva.12583}, abstractNote={Recent advances in research on gene drives have produced genetic constructs that could theoretically spread a desired gene (payload) into all populations of a species, with a single release in one place. This attribute has advantages, but also comes with risks and ethical concerns. There has been a call for research on gene drive systems that are spatially and/or temporally self-limiting. Here, we use a population genetics model to compare the expected characteristics of three spatially self-limiting gene drive systems: one-locus underdominance, two-locus underdominance and daisy-chain drives. We find large differences between these gene drives in the minimum release size required for successfully driving a payload into a population. The daisy-chain system is the most efficient, requiring the smallest release, followed by the two-locus underdominance system, and then the one-locus underdominance system. However, when the target population exchanges migrants with a nontarget population, the gene drives requiring smaller releases suffer from higher risks of unintended spread. For payloads that incur relatively low fitness costs (up to 30%), a simple daisy-chain drive is practically incapable of remaining localized, even with migration rates as low as 0.5% per generation. The two-locus underdominance system can achieve localized spread under a broader range of migration rates and of payload fitness costs, while the one-locus underdominance system largely remains localized. We also find differences in the extent of population alteration and in the permanence of the alteration achieved by the three gene drives. The two-locus underdominance system does not always spread the payload to fixation, even after successful drive, while the daisy-chain system can, for a small set of parameter values, achieve a temporally limited spread of the payload. These differences could affect the suitability of each gene drive for specific applications.}, number={5}, journal={Evolutionary Applications}, publisher={Wiley}, author={Dhole, Sumit and Vella, Michael R. and Lloyd, Alun L. and Gould, Fred}, year={2018}, month={Jan}, pages={794–808} }
 @article{oppenheim_gould_hopper_2018, title={The genetic architecture of ecological adaptation: intraspecific variation in host plant use by the lepidopteran crop pest Chloridea virescens}, volume={120}, ISSN={["1365-2540"]}, DOI={10.1038/s41437-017-0016-3}, abstractNote={Intraspecific variation in ecologically important traits is a cornerstone of Darwin’s theory of evolution by natural selection. The evolution and maintenance of this variation depends on genetic architecture, which in turn determines responses to natural selection. Some models suggest that traits with complex architectures are less likely to respond to selection than those with simple architectures, yet rapid divergence has been observed in such traits. The simultaneous evolutionary lability and genetic complexity of host plant use in the Lepidopteran subfamily Heliothinae suggest that architecture may not constrain ecological adaptation in this group. Here we investigate the response of Chloridea virescens, a generalist that feeds on diverse plant species, to selection for performance on a novel host, Physalis angulata (Solanaceae). P. angulata is the preferred host of Chloridea subflexa, a narrow specialist on the genus Physalis. In previous experiments, we found that the performance of C. subflexa on P. angulata depends on many loci of small effect distributed throughout the genome, but whether the same architecture would be involved in the generalist’s adoption of P. angulata was unknown. Here we report a rapid response to selection in C. virescens for performance on P. angulata, and establish that the genetic architecture of intraspecific variation is quite similar to that of the interspecific differences in terms of the number, distribution, and effect sizes of the QTL involved. We discuss the impact of genetic architecture on the ability of Heliothine moths to respond to varying ecological selection pressures.}, number={3}, journal={HEREDITY}, author={Oppenheim, Sara J. and Gould, Fred and Hopper, Keith R.}, year={2018}, month={Mar}, pages={234–250} }
 @article{gould_brown_kuzma_2018, title={Wicked evolution: Can we address the sociobiological dilemma of pesticide resistance?}, volume={360}, ISSN={0036-8075 1095-9203}, url={http://dx.doi.org/10.1126/science.aar3780}, DOI={10.1126/science.aar3780}, abstractNote={Resistance to insecticides and herbicides has cost billions of U.S. dollars in the agricultural sector and could result in millions of lives lost to insect-vectored diseases. We mostly continue to use pesticides as if resistance is a temporary issue that will be addressed by commercialization of new pesticides with novel modes of action. However, current evidence suggests that insect and weed evolution may outstrip our ability to replace outmoded chemicals and other control mechanisms. To avoid this outcome, we must address the mix of ecological, genetic, economic, and sociopolitical factors that prevent implementation of sustainable pest management practices. We offer an ambitious proposition.}, number={6390}, journal={Science}, publisher={American Association for the Advancement of Science (AAAS)}, author={Gould, Fred and Brown, Zachary S. and Kuzma, Jennifer}, year={2018}, month={May}, pages={728–732} }
 @article{delborne_kuzma_gould_frow_leitschuh_sudweeks_2018, title={‘Mapping research and governance needs for gene drives’}, volume={5}, ISSN={2329-9460 2329-9037}, url={http://dx.doi.org/10.1080/23299460.2017.1419413}, DOI={10.1080/23299460.2017.1419413}, abstractNote={A gene drive is a mechanism that biases inheritance of a trait in a sexually reproducing species of organisms. In this context, ‘bias’ means to increase the odds of a parent passing on a portion of...}, number={sup1}, journal={Journal of Responsible Innovation}, publisher={Informa UK Limited}, author={Delborne, Jason and Kuzma, Jennifer and Gould, Fred and Frow, Emma and Leitschuh, Caroline and Sudweeks, Jayce}, year={2018}, month={Jan}, pages={S4–S12} }
 @article{scott_gould_lorenzen_grubbs_edwards_o’brochta_2017, title={Agricultural production: assessment of the potential use of Cas9-mediated gene drive systems for agricultural pest control}, volume={5}, ISSN={2329-9460 2329-9037}, url={http://dx.doi.org/10.1080/23299460.2017.1410343}, DOI={10.1080/23299460.2017.1410343}, abstractNote={To highlight how gene drives could be useful for control of agricultural insect pests, we selected species that are pests of animals (New World screwworm), plants (spotted wing Drosophila, diamondback moth, Bemisia tabaci whitefly), or stored grains (red flour beetle). With the exception of whitefly, routine methods for delivering DNA to the germline and selecting for genetically modified insects have been developed. The traditional approach in agriculture has been to suppress insect pest populations using insecticides and other farming practices. Similarly, we suggest the main use of gene drives in agriculture will be for population suppression through targeting essential genes. We provide examples of gene drives that target specific genes including female-essential genes. Further, we discuss issues related to containment in the laboratory and eventual field testing of strains harboring a Cas9-mediated gene drive system.}, number={sup1}, journal={Journal of Responsible Innovation}, publisher={Informa UK Limited}, author={Scott, Maxwell J. and Gould, Fred and Lorenzen, Marcé and Grubbs, Nathaniel and Edwards, Owain and O’Brochta, David}, year={2017}, month={Dec}, pages={S98–S120} }
 @article{gould_amasino_brossard_buell_dixon_falck-zepeda_gallo_giller_glenna_griffin_et al._2017, title={Elevating the conversation about GE crops}, volume={35}, ISSN={1087-0156 1546-1696}, url={http://dx.doi.org/10.1038/NBT.3841}, DOI={10.1038/NBT.3841}, number={4}, journal={Nature Biotechnology}, publisher={Springer Nature}, author={Gould, Fred and Amasino, Richard M and Brossard, Dominique and Buell, C Robin and Dixon, Richard A and Falck-Zepeda, Jose B and Gallo, Michael A and Giller, Ken E and Glenna, Leland L and Griffin, Timothy and et al.}, year={2017}, month={Apr}, pages={302–304} }
 @article{vella_gunning_lloyd_gould_2017, title={Evaluating strategies for reversing CRISPR-Cas9 gene drives}, volume={7}, ISSN={2045-2322}, url={http://dx.doi.org/10.1038/s41598-017-10633-2}, DOI={10.1038/s41598-017-10633-2}, abstractNote={A gene drive biases inheritance of a gene so that it increases in frequency within a population even when the gene confers no fitness benefit. There has been renewed interest in environmental releases of engineered gene drives due to recent proof of principle experiments with the CRISPR-Cas9 system as a drive mechanism. Release of modified organisms, however, is controversial, especially when the drive mechanism could theoretically alter all individuals of a species. Thus, it is desirable to have countermeasures to reverse a drive if a problem arises. Several genetic mechanisms for limiting or eliminating gene drives have been proposed and/or developed, including synthetic resistance, reversal drives, and immunizing reversal drives. While predictions about efficacy of these mechanisms have been optimistic, we lack detailed analyses of their expected dynamics. We develop a discrete time model for population genetics of a drive and proposed genetic countermeasures. Efficacy of drive reversal varies between countermeasures. For some parameter values, the model predicts unexpected behavior including polymorphic equilibria and oscillatory dynamics. The timing and number of released individuals containing a genetic countermeasure can substantially impact outcomes. The choice among countermeasures by researchers and regulators will depend on specific goals and population parameters of target populations.}, number={1}, journal={Scientific Reports}, publisher={Springer Nature}, author={Vella, Michael R. and Gunning, Christian E. and Lloyd, Alun L. and Gould, Fred}, year={2017}, month={Sep} }
 @article{fritz_paa_baltzegar_gould_2016, title={Application of a dense genetic map for assessment of genomic responses to selection and inbreeding in Heliothis virescens}, volume={25}, ISSN={["1365-2583"]}, DOI={10.1111/imb.12234}, abstractNote={Adaptation of pest species to laboratory conditions and selection for resistance to toxins in the laboratory are expected to cause inbreeding and genetic bottlenecks that reduce genetic variation. Heliothis virescens, a major cotton pest, has been colonized in the laboratory many times, and a few laboratory colonies have been selected for Bacillus thuringiensis (Bt) resistance. We developed 350-bp double-digest restriction-site associated DNA-sequencing (ddRAD-seq) molecular markers to examine and compare changes in genetic variation associated with laboratory adaptation, artificial selection and inbreeding in this nonmodel insect species. We found that allelic and nucleotide diversity declined dramatically in laboratory-reared H. virescens as compared with field-collected populations. The declines were primarily a result of the loss of low frequency alleles present in field-collected H. virescens. A further, albeit modest decline in genetic diversity was observed in a Bt-selected population. The greatest decline was seen in H. virescens that were sib-mated for 10 generations, in which more than 80% of loci were fixed for a single allele. To determine which regions of the genome were resistant to fixation in our sib-mated line, we generated a dense intraspecific linkage map containing three PCR-based and 659 ddRAD-seq markers. Markers that retained polymorphism were observed in small clusters spread over multiple linkage groups, but this clustering was not statistically significant. Overall, we have confirmed and extended the general expectations for reduced genetic diversity in laboratory colonies, provided tools for further genomic analyses and produced highly homozygous genomic DNA for future whole genome sequencing of H. virescens.}, number={4}, journal={INSECT MOLECULAR BIOLOGY}, author={Fritz, M. L. and Paa, S. and Baltzegar, J. and Gould, F.}, year={2016}, month={Aug}, pages={385–400} }
 @article{legros_otero_romeo aznar_solari_gould_lloyd_2016, title={Comparison of two detailed models of Aedes aegypti
 population dynamics}, volume={7}, ISSN={2150-8925}, url={http://dx.doi.org/10.1002/ecs2.1515}, DOI={10.1002/ecs2.1515}, abstractNote={The success of control programs for mosquito borne diseases can be enhanced by crucial information provided by models of the mosquito populations. Models, however, can differ in their structure, complexity and biological assumptions, and these differences impact their predictions. Unfortunately, it is typically difficult to determine why two complex models make different predictions because we lack structured side-by-side comparisons of models using comparable parameterization. Here we present a detailed comparison of two complex, spatially-explicit, stochastic models of the population dynamics of Aedes aegypti, the main vector of dengue, yellow fever, chikungunya and Zika viruses. Both models describe the mosquito's biological and ecological characteristics, but differ in complexity and specific assumptions. We compare the predictions of these models in two selected climatic settings, a tropical and weakly seasonal climate in Iquitos, Peru, and a temperate and strongly seasonal climate in Buenos Aires, Argentina. Both models were calibrated to operate at identical average densities in unperturbed conditions in both settings, by adjusting parameters regulating densities in each model (number of larval development sites and amount of nutritional resources). We show that the models differ in their sensitivity to environmental conditions (temperature and rainfall), and trace differences to specific model assumptions. Temporal dynamics of the Ae. aegypti populations predicted by the two models differ more markedly under strongly seasonal Buenos Aires conditions. We use both models to simulate killing of larvae and/or adults with insecticides in selected areas. We show that predictions of population recovery by the models differ substantially, an effect likely related to model assumptions regarding larval development and (direct or delayed) density dependence. Our methodical comparison provides important guidance for model improvement by identifying key areas of Ae. aegypti ecology that substantially affect model predictions, and revealing the impact of model assumptions on population dynamics predictions in unperturbed and perturbed conditions.}, number={10}, journal={Ecosphere}, publisher={Wiley}, author={Legros, Mathieu and Otero, Marcelo and Romeo Aznar, Victoria and Solari, Hernan and Gould, Fred and Lloyd, Alun L.}, year={2016}, month={Oct}, pages={e01515} }
 @article{okamoto_gould_lloyd_2016, title={Integrating Transgenic Vector Manipulation with Clinical Interventions to Manage Vector-Borne Diseases}, volume={12}, ISSN={1553-7358}, url={http://dx.doi.org/10.1371/journal.pcbi.1004695}, DOI={10.1371/journal.pcbi.1004695}, abstractNote={Many vector-borne diseases lack effective vaccines and medications, and the limitations of traditional vector control have inspired novel approaches based on using genetic engineering to manipulate vector populations and thereby reduce transmission. Yet both the short- and long-term epidemiological effects of these transgenic strategies are highly uncertain. If neither vaccines, medications, nor transgenic strategies can by themselves suffice for managing vector-borne diseases, integrating these approaches becomes key. Here we develop a framework to evaluate how clinical interventions (i.e., vaccination and medication) can be integrated with transgenic vector manipulation strategies to prevent disease invasion and reduce disease incidence. We show that the ability of clinical interventions to accelerate disease suppression can depend on the nature of the transgenic manipulation deployed (e.g., whether vector population reduction or replacement is attempted). We find that making a specific, individual strategy highly effective may not be necessary for attaining public-health objectives, provided suitable combinations can be adopted. However, we show how combining only partially effective antimicrobial drugs or vaccination with transgenic vector manipulations that merely temporarily lower vector competence can amplify disease resurgence following transient suppression. Thus, transgenic vector manipulation that cannot be sustained can have adverse consequences—consequences which ineffective clinical interventions can at best only mitigate, and at worst temporarily exacerbate. This result, which arises from differences between the time scale on which the interventions affect disease dynamics and the time scale of host population dynamics, highlights the importance of accounting for the potential delay in the effects of deploying public health strategies on long-term disease incidence. We find that for systems at the disease-endemic equilibrium, even modest perturbations induced by weak interventions can exhibit strong, albeit transient, epidemiological effects. This, together with our finding that under some conditions combining strategies could have transient adverse epidemiological effects suggests that a relatively long time horizon may be necessary to discern the efficacy of alternative intervention strategies.}, number={3}, journal={PLOS Computational Biology}, publisher={Public Library of Science (PLoS)}, author={Okamoto, Kenichi W. and Gould, Fred and Lloyd, Alun L.}, editor={Alizon, SamuelEditor}, year={2016}, month={Mar}, pages={e1004695} }
 @misc{achee_gould_perkins_reiner_morrison_ritchie_gubler_teyssou_scott_2015, title={A Critical Assessment of Vector Control for Dengue Prevention}, volume={9}, ISSN={["1935-2735"]}, DOI={10.1371/journal.pntd.0003655}, abstractNote={Recently, the Vaccines to Vaccinate (v2V) initiative was reconfigured into the Partnership for Dengue Control (PDC), a multi-sponsored and independent initiative. This redirection is consistent with the growing consensus among the dengue-prevention community that no single intervention will be sufficient to control dengue disease. The PDC's expectation is that when an effective dengue virus (DENV) vaccine is commercially available, the public health community will continue to rely on vector control because the two strategies complement and enhance one another. Although the concept of integrated intervention for dengue prevention is gaining increasingly broader acceptance, to date, no consensus has been reached regarding the details of how and what combination of approaches can be most effectively implemented to manage disease. To fill that gap, the PDC proposed a three step process: (1) a critical assessment of current vector control tools and those under development, (2) outlining a research agenda for determining, in a definitive way, what existing tools work best, and (3) determining how to combine the best vector control options, which have systematically been defined in this process, with DENV vaccines. To address the first step, the PDC convened a meeting of international experts during November 2013 in Washington, DC, to critically assess existing vector control interventions and tools under development. This report summarizes those deliberations.}, number={5}, journal={PLOS NEGLECTED TROPICAL DISEASES}, author={Achee, Nicole L. and Gould, Fred and Perkins, T. Alex and Reiner, Robert C., Jr. and Morrison, Amy C. and Ritchie, Scott A. and Gubler, Duane J. and Teyssou, Remy and Scott, Thomas W.}, year={2015}, month={May} }
 @article{perera_shelby_popham_gould_adang_jurat-fuentes_2015, title={Generation of a Transcriptome in a Model Lepidopteran Pest, Heliothis virescens, Using Multiple Sequencing Strategies for Profiling Midgut Gene Expression}, volume={10}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0128563}, abstractNote={Heliothine pests such as the tobacco budworm, Heliothis virescens (F.), pose a significant threat to production of a variety of crops and ornamental plants and are models for developmental and physiological studies. The efforts to develop new control measures for H. virescens, as well as its use as a relevant biological model, are hampered by a lack of molecular resources. The present work demonstrates the utility of next-generation sequencing technologies for rapid molecular resource generation from this species for which lacks a sequenced genome. In order to amass a de novo transcriptome for this moth, transcript sequences generated from Illumina, Roche 454, and Sanger sequencing platforms were merged into a single de novo transcriptome assembly. This pooling strategy allowed a thorough sampling of transcripts produced under diverse environmental conditions, developmental stages, tissues, and infections with entomopathogens used for biological control, to provide the most complete transcriptome to date for this species. Over 138 million reads from the three platforms were assembled into the final set of 63,648 contigs. Of these, 29,978 had significant BLAST scores indicating orthologous relationships to transcripts of other insect species, with the top-hit species being the monarch butterfly (Danaus plexippus) and silkworm (Bombyx mori). Among identified H. virescens orthologs were immune effectors, signal transduction pathways, olfactory receptors, hormone biosynthetic pathways, peptide hormones and their receptors, digestive enzymes, and insecticide resistance enzymes. As an example, we demonstrate the utility of this transcriptomic resource to study gene expression profiling of larval midguts and detect transcripts of putative Bacillus thuringiensis (Bt) Cry toxin receptors. The substantial molecular resources described in this study will facilitate development of H. virescens as a relevant biological model for functional genomics and for new biological experimentation needed to develop efficient control efforts for this and related Noctuid pest moths.}, number={6}, journal={PLOS ONE}, author={Perera, Omaththage P. and Shelby, Kent S. and Popham, Holly J. R. and Gould, Fred and Adang, Michael J. and Jurat-Fuentes, Juan Luis}, year={2015}, month={Jun} }
 @article{an_gao_lei_gould_wu_2015, title={Monitoring cotton bollworm resistance to Cry1Ac in two counties of northern China during 2009-2013}, volume={71}, ISSN={["1526-4998"]}, DOI={10.1002/ps.3807}, abstractNote={BACKGROUND Transgenic cotton that expresses a gene derived from the bacterium Bacillus thuringiensis (Bt) has been deployed for combating cotton bollworm in China since 1997. As a follow-up on research started in 2002, the quantitative shifts in larval Cry1Ac resistance of field Helicoverpa armigera populations were monitored from 2009–2013 using bioassays of isofemale lines. RESULTS A total of 2837 lines from Xiajin and 2055 lines from Anci were screened for growth rate on normal artificial diet and on a diet containing 1.0 µg mL−1 of Cry1A(c) toxin. In 2009–2013, the mean relative average development rates (RADRs) of H. armigera larvae in the Xiajin population were 0.62, 0.59, 0.59, 0.58 and 0.62 respectively, and in the Anci population 0.54, 0.58, 0.60, 0.53 and 0.62 respectively. CONCLUSIONS Compared with previous results in 2002, there was an increase in the RADR of H. armigera during 2009–2013, with ratios of 1.53–1.63 and 1.77–2.07 in the respective Xiajin and Anci populations, suggesting that resistance to Cry1Ac has increased in H. armigera populations in northern China. © 2014 Society of Chemical Industry}, number={3}, journal={PEST MANAGEMENT SCIENCE}, author={An, Jingjie and Gao, Yulin and Lei, Chaoliang and Gould, Fred and Wu, Kongming}, year={2015}, month={Mar}, pages={377–382} }
 @article{campbell_beek_eason_glen_godwin_gould_holmes_howald_madden_ponder_et al._2015, title={The next generation of rodent eradications: Innovative technologies and tools to improve species specificity and increase their feasibility on islands}, volume={185}, ISSN={["1873-2917"]}, DOI={10.1016/j.biocon.2014.10.016}, abstractNote={Rodents remain one of the most widespread and damaging invasive alien species on islands globally. The current toolbox for insular rodent eradications is reliant on the application of sufficient anticoagulant toxicant into every potential rodent territory across an island. Despite significant advances in the use of these toxicants over recent decades, numerous situations remain where eradication is challenging or not yet feasible. These include islands with significant human populations, unreceptive stakeholder communities, co-occurrence of livestock and domestic animals, or vulnerability of native species. Developments in diverse branches of science, particularly the medical, pharmaceutical, invertebrate pest control, social science, technology and defense fields offer potential insights into the next generation of tools to eradicate rodents from islands. Horizon scanning is a structured process whereby current problems are assessed against potential future solutions. We undertook such an exercise to identify the most promising technologies, techniques and approaches that might be applied to rodent eradications from islands. We highlight a Rattus-specific toxicant, RNA interference as species-specific toxicants, rodenticide research, crab deterrent in baits, prophylactic treatment for protection of non-target species, transgenic rodents, virus vectored immunocontraception, drones, self-resetting traps and toxicant applicators, detection probability models and improved stakeholder community engagement methods. We present a brief description of each method, and discuss its application to rodent eradication on islands, knowledge gaps, challenges, whether it is incremental or transformative in nature and provide a potential timeline for availability. We outline how a combination of new tools may render previously intractable rodent eradication problems feasible.}, journal={BIOLOGICAL CONSERVATION}, author={Campbell, Karl J. and Beek, Joe and Eason, Charles T. and Glen, Alistair S. and Godwin, John and Gould, Fred and Holmes, Nick D. and Howald, Gregg R. and Madden, Francine M. and Ponder, Julia B. and et al.}, year={2015}, month={May}, pages={47–58} }
 @article{okamoto_robert_gould_lloyd_2014, title={Feasible Introgression of an Anti-pathogen Transgene into an Urban Mosquito Population without Using Gene-Drive}, volume={8}, ISSN={["1935-2735"]}, DOI={10.1371/journal.pntd.0002827}, abstractNote={Introgressing anti-pathogen constructs into wild vector populations could reduce disease transmission. It is generally assumed that such introgression would require linking an anti-pathogen gene with a selfish genetic element or similar technologies. Yet none of the proposed transgenic anti-pathogen gene-drive mechanisms are likely to be implemented as public health measures in the near future. Thus, much attention now focuses instead on transgenic strategies aimed at mosquito population suppression, an approach generally perceived to be practical. By contrast, aiming to replace vector competent mosquito populations with vector incompetent populations by releasing mosquitoes carrying a single anti-pathogen gene without a gene-drive mechanism is widely considered impractical.Here we use Skeeter Buster, a previously published stochastic, spatially explicit model of Aedes aegypti to investigate whether a number of approaches for releasing mosquitoes with only an anti-pathogen construct would be efficient and effective in the tropical city of Iquitos, Peru. To assess the performance of such releases using realistic release numbers, we compare the transient and long-term effects of this strategy with two other genetic control strategies that have been developed in Ae. aegypti: release of a strain with female-specific lethality, and a strain with both female-specific lethality and an anti-pathogen gene. We find that releasing mosquitoes carrying only an anti-pathogen construct can substantially decrease vector competence of a natural population, even at release ratios well below that required for the two currently feasible alternatives that rely on population reduction. Finally, although current genetic control strategies based on population reduction are compromised by immigration of wild-type mosquitoes, releasing mosquitoes carrying only an anti-pathogen gene is considerably more robust to such immigration.Contrary to the widely held view that transgenic control programs aimed at population replacement require linking an anti-pathogen gene to selfish genetic elements, we find releasing mosquitoes in numbers much smaller than those considered necessary for transgenic population reduction can result in comparatively rapid and robust population replacement. In light of this non-intuitive result, directing efforts to improve rearing capacity and logistical support for implementing releases, and reducing the fitness costs of existing recombinant technologies, may provide a viable, alternative route to introgressing anti-pathogen transgenes under field conditions.}, number={7}, journal={PLOS NEGLECTED TROPICAL DISEASES}, author={Okamoto, Kenichi W. and Robert, Michael A. and Gould, Fred and Lloyd, Alun L.}, year={2014}, month={Jul} }
 @article{thresher_hayes_bax_teem_benfey_gould_2014, title={Genetic control of invasive fish: technological options and its role in integrated pest management}, volume={16}, ISSN={["1573-1464"]}, DOI={10.1007/s10530-013-0477-0}, number={6}, journal={BIOLOGICAL INVASIONS}, author={Thresher, Ronald E. and Hayes, Keith and Bax, Nicholas J. and Teem, John and Benfey, Tillmann J. and Gould, Fred}, year={2014}, month={Jun}, pages={1201–1216} }
 @article{groot_schöfl_inglis_donnerhacke_classen_schmalz_santangelo_emerson_gould_schal_et al._2014, title={Within-population variability in a moth sex pheromone blend: genetic basis and behavioural consequences}, volume={281}, ISSN={0962-8452 1471-2954}, url={http://dx.doi.org/10.1098/rspb.2013.3054}, DOI={10.1098/rspb.2013.3054}, abstractNote={Evolutionary diversification of sexual communication systems in moths is perplexing because signal and response are under stabilizing selection in many species, and this is expected to constrain evolutionary change. In the moth Heliothis virescens , we consistently found high phenotypic variability in the female sex pheromone blend within each of four geographically distant populations. Here, we assess the heritability, genetic basis and behavioural consequences of this variation. Artificial selection with field-collected moths dramatically increased the relative amount of the saturated compound 16:Ald and decreased its unsaturated counterpart Z11–16:Ald, the major sex pheromone component (high line). In a cross between the high- and low-selected lines, one quantitative trait locus (QTL) explained 11–21% of the phenotypic variance in the 16:Ald/Z11–16:Ald ratio. Because changes in activity of desaturase enzymes could affect this ratio, we measured their expression levels in pheromone glands and mapped desaturase genes onto our linkage map. A delta-11-desaturase had lower expression in females producing less Z11–16:Ald; however, this gene mapped to a different chromosome than the QTL. A model in which the QTL is a trans-acting repressor of delta-11 desaturase expression explains many features of the data. Selection favouring heterozygotes which produce more unsaturated components could maintain a polymorphism at this locus.}, number={1779}, journal={Proceedings of the Royal Society B: Biological Sciences}, publisher={The Royal Society}, author={Groot, Astrid T. and Schöfl, Gerhard and Inglis, Ollie and Donnerhacke, Susanne and Classen, Alice and Schmalz, Antje and Santangelo, Richard G. and Emerson, Jennifer and Gould, Fred and Schal, Coby and et al.}, year={2014}, month={Mar}, pages={20133054} }
 @article{robert_okamoto_lloyd_gould_2013, title={A Reduce and Replace Strategy for Suppressing Vector-Borne Diseases: Insights from a Deterministic Model}, volume={8}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0073233}, abstractNote={Genetic approaches for controlling disease vectors have aimed either to reduce wild-type populations or to replace wild-type populations with insects that cannot transmit pathogens. Here, we propose a Reduce and Replace (R&R) strategy in which released insects have both female-killing and anti-pathogen genes. We develop a mathematical model to numerically explore release strategies involving an R&R strain of the dengue vector Aedes aegypti. We show that repeated R&R releases may lead to a temporary decrease in mosquito population density and, in the absence of fitness costs associated with the anti-pathogen gene, a long-term decrease in competent vector population density. We find that R&R releases more rapidly reduce the transient and long-term competent vector densities than female-killing releases alone. We show that releases including R&R females lead to greater reduction in competent vector density than male-only releases. The magnitude of reduction in total and competent vectors depends upon the release ratio, release duration, and whether females are included in releases. Even when the anti-pathogen allele has a fitness cost, R&R releases lead to greater reduction in competent vectors than female-killing releases during the release period; however, continued releases are needed to maintain low density of competent vectors long-term. We discuss the results of the model as motivation for more detailed studies of R&R strategies.}, number={9}, journal={PLOS ONE}, author={Robert, Michael A. and Okamoto, Kenichi and Lloyd, Alun L. and Gould, Fred}, year={2013}, month={Sep} }
 @article{huang_wan_zhang_huang_li_gould_2013, title={Diminishing Returns from Increased Percent Bt Cotton: The Case of Pink Bollworm}, volume={8}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0068573}, abstractNote={Regional suppression of pests by transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) has been reported in several cropping systems, but little is known about the functional relationship between the ultimate pest population density and the pervasiveness of Bt crops. Here we address this issue by analyzing 16 years of field data on pink bollworm (Pectinophora gossypiella) population density and percentage of Bt cotton in the Yangtze River Valley of China. In this region, the percentage of cotton hectares planted with Bt cotton increased from 9% in 2000 to 94% in 2009 and 2010. We find that as the percent Bt cotton increased over the years, the cross-year growth rate of pink bollworm from the last generation of one year to the first generation of the next year decreased. However, as the percent Bt cotton increased, the within-year growth rate of pink bollworm from the first to last generation of the same year increased, with a slope approximately opposite to that of the cross-year rates. As a result, we did not find a statistically significant decline in the annual growth rate of pink bollworm as the percent Bt cotton increased over time. Consistent with the data, our modeling analyses predict that the regional average density of pink bollworm declines as the percent Bt cotton increases, but the higher the percent Bt cotton, the slower the decline in pest density. Specifically, we find that 95% Bt cotton is predicted to cause only 3% more reduction in larval density than 80% Bt cotton. The results here suggest that density dependence can act against the decline in pest density and diminish the net effects of Bt cotton on suppression of pink bollworm in the study region. The findings call for more studies of the interactions between pest density-dependence and Bt crops.}, number={7}, journal={PLOS ONE}, author={Huang, Yunxin and Wan, Peng and Zhang, Huannan and Huang, Minsong and Li, Zhaohua and Gould, Fred}, year={2013}, month={Jul} }
 @article{facchinelli_valerio_ramsey_gould_walsh_bond_robert_lloyd_james_alphey_et al._2013, title={Field Cage Studies and Progressive Evaluation of Genetically-Engineered Mosquitoes}, volume={7}, ISSN={["1935-2735"]}, DOI={10.1371/journal.pntd.0002001}, abstractNote={A genetically-engineered strain of the dengue mosquito vector Aedes aegypti, designated OX3604C, was evaluated in large outdoor cage trials for its potential to improve dengue prevention efforts by inducing population suppression. OX3604C is engineered with a repressible genetic construct that causes a female-specific flightless phenotype. Wild-type females that mate with homozygous OX3604C males will not produce reproductive female offspring. Weekly introductions of OX3604C males eliminated all three targeted Ae. aegypti populations after 10-20 weeks in a previous laboratory cage experiment. As part of the phased, progressive evaluation of this technology, we carried out an assessment in large outdoor field enclosures in dengue endemic southern Mexico.OX3604C males were introduced weekly into field cages containing stable target populations, initially at 10:1 ratios. Statistically significant target population decreases were detected in 4 of 5 treatment cages after 17 weeks, but none of the treatment populations were eliminated. Mating competitiveness experiments, carried out to explore the discrepancy between lab and field cage results revealed a maximum mating disadvantage of up 59.1% for OX3604C males, which accounted for a significant part of the 97% fitness cost predicted by a mathematical model to be necessary to produce the field cage results.Our results indicate that OX3604C may not be effective in large-scale releases. A strain with the same transgene that is not encumbered by a large mating disadvantage, however, could have improved prospects for dengue prevention. Insights from large outdoor cage experiments may provide an important part of the progressive, stepwise evaluation of genetically-engineered mosquitoes.}, number={1}, journal={PLOS NEGLECTED TROPICAL DISEASES}, author={Facchinelli, Luca and Valerio, Laura and Ramsey, Janine M. and Gould, Fred and Walsh, Rachael K. and Bond, Guillermo and Robert, Michael A. and Lloyd, Alun L. and James, Anthony A. and Alphey, Luke and et al.}, year={2013}, month={Jan} }
 @article{legros_xu_morrison_scott_lloyd_gould_2013, title={Modeling the Dynamics of a Non-Limited and a Self-Limited Gene Drive System in Structured Aedes aegypti Populations}, volume={8}, ISSN={1932-6203}, url={http://dx.doi.org/10.1371/journal.pone.0083354}, DOI={10.1371/journal.pone.0083354}, abstractNote={Recently there have been significant advances in research on genetic strategies to control populations of disease-vectoring insects. Some of these strategies use the gene drive properties of selfish genetic elements to spread physically linked anti-pathogen genes into local vector populations. Because of the potential of these selfish elements to spread through populations, control approaches based on these strategies must be carefully evaluated to ensure a balance between the desirable spread of the refractoriness-conferring genetic cargo and the avoidance of potentially unwanted outcomes such as spread to non-target populations. There is also a need to develop better estimates of the economics of such releases. We present here an evaluation of two such strategies using a biologically realistic mathematical model that simulates the resident Aedes aegypti mosquito population of Iquitos, Peru. One strategy uses the selfish element Medea, a non-limited element that could permanently spread over a large geographic area; the other strategy relies on Killer-Rescue genetic constructs, and has been predicted to have limited spatial and temporal spread. We simulate various operational approaches for deploying these genetic strategies, and quantify the optimal number of released transgenic mosquitoes needed to achieve definitive spread of Medea-linked genes and/or high frequencies of Killer-Rescue-associated elements. We show that for both strategies the most efficient approach for achieving spread of anti-pathogen genes within three years is generally to release adults of both sexes in multiple releases over time. Even though females in these releases should not transmit disease, there could be public concern over such releases, making the less efficient male-only release more practical. This study provides guidelines for operational approaches to population replacement genetic strategies, as well as illustrates the use of detailed spatial models to assist in safe and efficient implementation of such novel genetic strategies.}, number={12}, journal={PLoS ONE}, publisher={Public Library of Science (PLoS)}, author={Legros, Mathieu and Xu, Chonggang and Morrison, Amy and Scott, Thomas W. and Lloyd, Alun L. and Gould, Fred}, editor={Adelman, Zach NEditor}, year={2013}, month={Dec}, pages={e83354} }
 @article{groot_staudacher_barthel_inglis_schöfl_santangelo_gebauer‐jung_vogel_emerson_schal_et al._2013, title={One quantitative trait locus for intra‐ and interspecific variation in a sex pheromone}, volume={22}, ISSN={0962-1083 1365-294X}, url={http://dx.doi.org/10.1111/mec.12171}, DOI={10.1111/mec.12171}, abstractNote={Even though premating isolation is hypothesized to be a major driving force in speciation, its genetic basis is poorly known. In the noctuid moth Heliothis subflexa, one group of sex pheromone components, the acetates, emitted by the female, plays a crucial isolating role in preventing interspecific matings to males of the closely related Heliothis virescens, in which females do not produce acetates and males are repelled by them. We previously found intraspecific variation in acetates in H. subflexa: females in eastern North America contain significantly more acetates than females in Western Mexico. Here we describe the persistence of this intraspecific variation in laboratory-reared strains and the identification of one major quantitative trait locus (QTL), explaining 40% of the variance in acetate amounts. We homologized this intraspecific QTL to our previously identified interspecific QTL using restriction-associated DNA (RAD) tags. We found that a major intraspecific QTL overlaps with one of the two major interspecific QTL. To identify candidate genes underlying the acetate variation, we investigated a number of gene families with known or suspected acetyl- or acyltransferase activity. The most likely candidate genes did not map to our QTL, so that we currently hypothesize that a transcription factor underlies this QTL. Finding a single, large QTL that impacts variation in pheromone blends between and within species is, to our knowledge, the first such example for traits that have been demonstrated to affect premating isolation.}, number={4}, journal={Molecular Ecology}, publisher={Wiley}, author={Groot, A. T. and Staudacher, H. and Barthel, A. and Inglis, O. and Schöfl, G. and Santangelo, R. G. and Gebauer‐Jung, S. and Vogel, H. and Emerson, J. and Schal, C. and et al.}, year={2013}, month={Jan}, pages={1065–1080} }
 @article{walsh_gould_lloyd_scott_ramsey_valerio_facchinelli_aguilar_2013, title={Regulation of Aedes aegypti Population Dynamics in Field Systems: Quantifying Direct and Delayed Density Dependence}, volume={89}, ISSN={0002-9637 1476-1645}, url={http://dx.doi.org/10.4269/ajtmh.12-0378}, DOI={10.4269/ajtmh.12-0378}, abstractNote={Transgenic strains of Aedes aegypti have been engineered to help control transmission of dengue virus. Although resources have been invested in developing the strains, we lack data on the ecology of mosquitoes that could impact the success of this approach. Although studies of intra-specific competition have been conducted using Ae. aegypti larvae, none of these studies examine mixed age cohorts at densities that occur in the field, with natural nutrient levels. Experiments were conducted in Mexico to determine the impact of direct and delayed density dependence on Ae. aegypti populations. Natural water, food, and larval densities were used to estimate the impacts of density dependence on larval survival, development, and adult body size. Direct and delayed density-dependent factors had a significant impact on larval survival, larval development, and adult body size. These results indicate that control methods attempting to reduce mosquito populations may be counteracted by density-dependent population regulation.}, number={1}, journal={The American Journal of Tropical Medicine and Hygiene}, publisher={American Society of Tropical Medicine and Hygiene}, author={Walsh, Rachael K. and Gould, Fred and Lloyd, Alun L. and Scott, Thomas W. and Ramsey, Janine M. and Valerio, Laura and Facchinelli, Luca and Aguilar, Cristobal L.}, year={2013}, month={Jul}, pages={68–77} }
 @article{vasquez_syed_estes_leal_gould_2013, title={Specificity of the receptor for the major sex pheromone component in Heliothis virescens}, volume={13}, DOI={10.1673/031.013.16001}, abstractNote={In a previous study, the Drosophila melanogaster OR67d(GAL4);UAS system was used to functionally characterize the receptor for the major component of the sex pheromone in the tobacco budworm, Heliothis virescens Fabricius (Lepidoptera: Noctuidae), HvOR13. Electrophysiological and behavioral assays showed that transgenic flies expressing HvOR13 responded to (Z)-11-hexadecenal (Z11-16:Ald). However, tests were not performed to determine whether these flies would also respond to secondary components of the H. virescens sex pheromone. Thus, in this study the response spectrum of HvOR13 expressed in this system was examined by performing single cell recordings from odor receptor neuron in trichoid T1 sensilla on antennae of two Or67d(GAL4 [1]); UAS-HvOR13 lines stimulated with Z11-16:Ald and six H. virescens secondary pheromone components. Fly courtship assays were also performed to examine the behavioral response of the Or67d(GAL4[1]); UAS-HvOR13 flies to Z11-16:Ald and the secondary component Z9-14:Ald. Our combined electrophysiological and behavioral studies indicated high specificity and sensitivity of HvOR13 to Z11-16:Ald. Interestingly, a mutation leading to truncation in the HvOR13 C-terminal region affected but did not abolish pheromone receptor response to Z11-16:Ald. The findings are assessed in relationship to other HvOR13 heterologous expression studies, and the role of the C-terminal domain in receptor function is discussed. A third line expressing HvOR15 was also tested but did not respond to any of the seven pheromone components.}, journal={Journal of Insect Science (Tucson, AZ)}, author={Vasquez, G. M. and Syed, Z. and Estes, P. A. and Leal, W. S. and Gould, F.}, year={2013} }
 @misc{gatton_chitnis_churcher_donnelly_ghani_godfray_gould_hastings_marshall_ranson_et al._2013, title={THE IMPORTANCE OF MOSQUITO BEHAVIOURAL ADAPTATIONS TO MALARIA CONTROL IN AFRICA}, volume={67}, ISSN={["1558-5646"]}, DOI={10.1111/evo.12063}, abstractNote={Over the past decade the use of long‐lasting insecticidal nets (LLINs), in combination with improved drug therapies, indoor residual spraying (IRS), and better health infrastructure, has helped reduce malaria in many African countries for the first time in a generation. However, insecticide resistance in the vector is an evolving threat to these gains. We review emerging and historical data on behavioral resistance in response to LLINs and IRS. Overall the current literature suggests behavioral and species changes may be emerging, but the data are sparse and, at times unconvincing. However, preliminary modeling has demonstrated that behavioral resistance could have significant impacts on the effectiveness of malaria control. We propose seven recommendations to improve understanding of resistance in malaria vectors. Determining the public health impact of physiological and behavioral insecticide resistance is an urgent priority if we are to maintain the significant gains made in reducing malaria morbidity and mortality.}, number={4}, journal={EVOLUTION}, author={Gatton, Michelle L. and Chitnis, Nakul and Churcher, Thomas and Donnelly, Martin J. and Ghani, Azra C. and Godfray, H. Charles J. and Gould, Fred and Hastings, Ian and Marshall, John and Ranson, Hilary and et al.}, year={2013}, month={Apr}, pages={1218–1230} }
 @article{walsh_bradley_apperson_gould_2012, title={An Experimental Field Study of Delayed Density Dependence in Natural Populations of Aedes albopictus}, volume={7}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0035959}, abstractNote={Aedes albopictus, a species known to transmit dengue and chikungunya viruses, is primarily a container-inhabiting mosquito. The potential for pathogen transmission by Ae. albopictus has increased our need to understand its ecology and population dynamics. Two parameters that we know little about are the impact of direct density-dependence and delayed density-dependence in the larval stage. The present study uses a manipulative experimental design, under field conditions, to understand the impact of delayed density dependence in a natural population of Ae. albopictus in Raleigh, North Carolina. Twenty liter buckets, divided in half prior to experimentation, placed in the field accumulated rainwater and detritus, providing oviposition and larval production sites for natural populations of Ae. albopictus. Two treatments, a larvae present and larvae absent treatment, were produced in each bucket. After five weeks all larvae were removed from both treatments and the buckets were covered with fine mesh cloth. Equal numbers of first instars were added to both treatments in every bucket. Pupae were collected daily and adults were frozen as they emerged. We found a significant impact of delayed density-dependence on larval survival, development time and adult body size in containers with high larval densities. Our results indicate that delayed density-dependence will have negative impacts on the mosquito population when larval densities are high enough to deplete accessible nutrients faster than the rate of natural food accumulation.}, number={4}, journal={PLOS ONE}, author={Walsh, Rachael K. and Bradley, Caitlin and Apperson, Charles S. and Gould, Fred}, year={2012}, month={Apr} }
 @article{legros_xu_okamoto_scott_morrison_lloyd_gould_2012, title={Assessing the Feasibility of Controlling Aedes aegypti with Transgenic Methods: A Model-Based Evaluation}, volume={7}, ISSN={1932-6203}, url={http://dx.doi.org/10.1371/journal.pone.0052235}, DOI={10.1371/journal.pone.0052235}, abstractNote={Suppression of dengue and malaria through releases of genetically engineered mosquitoes might soon become feasible. Aedes aegypti mosquitoes carrying a conditionally lethal transgene have recently been used to suppress local vector populations in small-scale field releases. Prior to releases of transgenic insects on a wider scale, however, most regulatory authorities will require additional evidence that suppression will be effective in natural heterogeneous habitats. We use a spatially explicit stochastic model of an Ae. aegypti population in Iquitos, Peru, along with an uncertainty analysis of its predictions, to quantitatively assess the outcome of varied operational approaches for releases of transgenic strains with conditional death of females. We show that population elimination might be an unrealistic objective in heterogeneous populations. We demonstrate that substantial suppression can nonetheless be achieved if releases are deployed in a uniform spatial pattern using strains combining multiple lethal elements, illustrating the importance of detailed spatial models for guiding genetic mosquito control strategies.}, number={12}, journal={PLoS ONE}, publisher={Public Library of Science (PLoS)}, author={Legros, Mathieu and Xu, Chonggang and Okamoto, Kenichi and Scott, Thomas W. and Morrison, Amy C. and Lloyd, Alun L. and Gould, Fred}, editor={Vasilakis, NikosEditor}, year={2012}, month={Dec}, pages={e52235} }
 @misc{bergen_rowell_gould_servedio_2012, title={Stochasticity in Sexual Selection Enables Divergence: Implications for Moth Pheromone Evolution}, volume={39}, ISSN={["1934-2845"]}, DOI={10.1007/s11692-012-9176-5}, number={2}, journal={EVOLUTIONARY BIOLOGY}, author={Bergen, Elizabeth L. and Rowell, Jonathan T. and Gould, Fred and Servedio, Maria R.}, year={2012}, month={Jun}, pages={271–281} }
 @article{oppenheim_gould_hopper_2012, title={THE GENETIC ARCHITECTURE OF A COMPLEX ECOLOGICAL TRAIT: HOST PLANT USE IN THE SPECIALIST MOTH, HELIOTHIS SUBFLEXA}, volume={66}, ISSN={["1558-5646"]}, DOI={10.1111/j.1558-5646.2012.01712.x}, abstractNote={We used genetic mapping to examine the genetic architecture of differences in host plant use between two species of noctuid moths, Heliothis subflexa, a specialist on Physalis spp., and its close relative, the broad generalist H. virescens. We introgressed H. subflexa chromosomes into the H. virescens background and analyzed 1462 backcross insects. The effects of H. subflexa-origin chromosomes were small when measured as the percent variation explained in backcross populations (0.2–5%), but were larger when considered in relation to the interspecific difference explained (1.5–165%). Most significant chromosomes had effects on more than one trait, and their effects varied between years, sexes, and genetic backgrounds. Different chromosomes could produce similar phenotypes, suggesting that the same trait might be controlled by different chromosomes in different backcross populations. It appears that many loci of small effect contribute to the use of Physalis by H. subflexa. We hypothesize that behavioral changes may have paved the way for physiological adaptation to Physalis by the generalist ancestor of H. subflexa and H. virescens.}, number={11}, journal={EVOLUTION}, author={Oppenheim, Sara J. and Gould, Fred and Hopper, Keith R.}, year={2012}, month={Nov}, pages={3336–3351} }
 @article{walsh_facchinelli_ramsey_bond_gould_2011, title={Assessing the impact of density dependence in field populations of Aedes aegypti}, volume={36}, ISSN={["1948-7134"]}, DOI={10.1111/j.1948-7134.2011.00170.x}, abstractNote={Although many laboratory studies of intra-specific competition have been conducted with Ae. aegypti, there have been few studies in natural environments and none that examined density dependence in natural containers at normal field densities. Additionally, current mathematical models that predict Ae. aegypti population dynamics lack empirically-based functions for density-dependence. We performed field experiments in Tapachula, Mexico, where dengue is a significant public health concern. Twenty-one containers with natural food and water that already contained larvae were collected from local houses. Each container was divided in half and the naturally occurring larvae were apportioned in a manner that resulted in one side of the container (high density) having four times the density of the second side (low density). Larvae were counted and pupae were removed daily. Once adults emerged, wing span was measured to estimate body size. Density had a significant impact on larval survival, adult body size, and the time taken to transition from 4(th) instar to pupation. Increased density decreased larval survival by 20% and decreased wing length by an average of 0.19 mm. These results provide a starting point for a better understanding of density dependence in field populations of Ae. aegypti.}, number={2}, journal={JOURNAL OF VECTOR ECOLOGY}, author={Walsh, R. K. and Facchinelli, L. and Ramsey, J. M. and Bond, J. G. and Gould, F.}, year={2011}, month={Dec}, pages={300–307} }
 @article{vasquez_fischer_grozinger_gould_2011, title={Differential expression of odorant receptor genes involved in the sexual isolation of two Heliothis moths}, volume={20}, ISSN={["1365-2583"]}, DOI={10.1111/j.1365-2583.2010.01044.x}, abstractNote={Moth sexual communication systems are highly diverse, but the mechanisms underlying their evolutionary diversification remain unclear. Recently, genes coding for odorant receptors (ORs) OR6, OR14, OR15 and OR16 have been genetically associated with species-specific male response to female pheromone blends in Heliothis virescens (Hv) and Heliothis subflexa (Hs). Quantitative real-time PCR analysis indicates that expression of HvOR6, HsOR6, HvOR14, HsOR14, HvOR15 and HsOR15 is male biased, which supports the hypothesis that they have a role in mediating female sex pheromone detection. The genes HvOR14, HvOR15 and HvOR16 are expressed at higher levels than their corresponding orthologues HsOR14, HsOR15 and HsOR16 in male antennae, while HvOR6 and HsOR6 transcripts are equally abundant in male antennae. The lack of higher expression of any of the receptor genes in H. subflexa antennae suggests that interspecific sequence differences, rather than gene regulation differences, underly the species-specific male response to pheromone components.}, number={1}, journal={INSECT MOLECULAR BIOLOGY}, author={Vasquez, G. M. and Fischer, P. and Grozinger, C. M. and Gould, F.}, year={2011}, month={Feb}, pages={115–124} }
 @article{legros_magori_morrison_xu_scott_lloyd_gould_2011, title={Evaluation of Location-Specific Predictions by a Detailed Simulation Model of Aedes aegypti Populations}, volume={6}, ISSN={1932-6203}, url={http://dx.doi.org/10.1371/journal.pone.0022701}, DOI={10.1371/journal.pone.0022701}, abstractNote={Skeeter Buster is a stochastic, spatially explicit simulation model of Aedes aegypti populations, designed to predict the outcome of vector population control methods. In this study, we apply the model to two specific locations, the cities of Iquitos, Peru, and Buenos Aires, Argentina. These two sites differ in the amount of field data that is available for location-specific customization. By comparing output from Skeeter Buster to field observations in these two cases we evaluate population dynamics predictions by Skeeter Buster with varying degrees of customization.Skeeter Buster was customized to the Iquitos location by simulating the layout of houses and the associated distribution of water-holding containers, based on extensive surveys of Ae. aegypti populations and larval habitats that have been conducted in Iquitos for over 10 years. The model is calibrated by adjusting the food input into various types of containers to match their observed pupal productivity in the field. We contrast the output of this customized model to the data collected from the natural population, comparing pupal numbers and spatial distribution of pupae in the population. Our results show that Skeeter Buster replicates specific population dynamics and spatial structure of Ae. aegypti in Iquitos. We then show how Skeeter Buster can be customized for Buenos Aires, where we only had Ae. aegypti abundance data that was averaged across all locations. In the Argentina case Skeeter Buster provides a satisfactory simulation of temporal population dynamics across seasons.This model can provide a faithful description of Ae. aegypti populations, through a process of location-specific customization that is contingent on the amount of data available from field collections. We discuss limitations presented by some specific components of the model such as the description of food dynamics and challenges that these limitations bring to model evaluation.}, number={7}, journal={PLoS ONE}, publisher={Public Library of Science (PLoS)}, author={Legros, Mathieu and Magori, Krisztian and Morrison, Amy C. and Xu, Chonggang and Scott, Thomas W. and Lloyd, Alun L. and Gould, Fred}, editor={Ooi, Eng EongEditor}, year={2011}, month={Jul}, pages={e22701} }
 @article{benda_brownie_schal_gould_2011, title={Field Observations of Oviposition by a Specialist Herbivore on Plant Parts and Plant Species Unsuitable as Larval Food}, volume={40}, ISSN={0046-225X 0046-225X}, url={http://dx.doi.org/10.1603/EN09335}, DOI={10.1603/en09335}, abstractNote={Where a female places her eggs can have a major impact on the fitness of her offspring, especially for insects in which the winged adults are far more mobile than the neonates. Larvae of Heliothis subflexa (Guenee) (Lepidoptera: Noctuidae), a specialist moth phylogenetically nested within a generalist clade, feed only on fruit of some Physalis species. Field observations of the oviposition behavior of H. subflexa revealed that 1) females laid most of their eggs on leaves of the Physalis plant, despite the larvae's frugivorous diet, and 2) females laid nearly 20% of the eggs on nonhost plant species. Most eggs oviposited on nonhosts were placed close to the host plant-88% were within 15 cm of the Physalis plant. However, in a study of neonate movement, we found that a distance of 2 cm from the hatch site to the host plant significantly decreased the ability of neonates to establish on the host plant. The estimated fitness cost, quantified as reduced neonate survival, for females ovipositing on nonhosts is 8-17%. Many ecological and evolutionary factors could result in oviposition on less suitable host parts and on nonhosts. One possibility is that specialization on Physalis has recently evolved in H. subflexa, and females have not fully optimized their oviposition behavior. However, the fitness cost of oviposition on nonhosts may be balanced by fitness benefits of such behavior, such as faster decision-making and reduced predation.}, number={6}, journal={Environmental Entomology}, publisher={Oxford University Press (OUP)}, author={Benda, Nicole D. and Brownie, Cavell and Schal, Coby and Gould, Fred}, year={2011}, month={Dec}, pages={1478–1486} }
 @article{jurat-fuentes_karumbaiah_jakka_ning_liu_wu_jackson_gould_blanco_portilla_et al._2011, title={Reduced Levels of Membrane-Bound Alkaline Phosphatase Are Common to Lepidopteran Strains Resistant to Cry Toxins from Bacillus thuringiensis}, volume={6}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0017606}, abstractNote={Development of insect resistance is one of the main concerns with the use of transgenic crops expressing Cry toxins from the bacterium Bacillus thuringiensis. Identification of biomarkers would assist in the development of sensitive DNA-based methods to monitor evolution of resistance to Bt toxins in natural populations. We report on the proteomic and genomic detection of reduced levels of midgut membrane-bound alkaline phosphatase (mALP) as a common feature in strains of Cry-resistant Heliothis virescens, Helicoverpa armigera and Spodoptera frugiperda when compared to susceptible larvae. Reduced levels of H. virescens mALP protein (HvmALP) were detected by two dimensional differential in-gel electrophoresis (2D-DIGE) analysis in Cry-resistant compared to susceptible larvae, further supported by alkaline phosphatase activity assays and Western blotting. Through quantitative real-time polymerase chain reaction (qRT-PCR) we demonstrate that the reduction in HvmALP protein levels in resistant larvae are the result of reduced transcript amounts. Similar reductions in ALP activity and mALP transcript levels were also detected for a Cry1Ac-resistant strain of H. armigera and field-derived strains of S. frugiperda resistant to Cry1Fa. Considering the unique resistance and cross-resistance phenotypes of the insect strains used in this work, our data suggest that reduced mALP expression should be targeted for development of effective biomarkers for resistance to Cry toxins in lepidopteran pests.}, number={3}, journal={PLOS ONE}, author={Jurat-Fuentes, Juan Luis and Karumbaiah, Lohitash and Jakka, Siva Rama Krishna and Ning, Changming and Liu, Chenxi and Wu, Kongming and Jackson, Jerreme and Gould, Fred and Blanco, Carlos and Portilla, Maribel and et al.}, year={2011}, month={Mar} }
 @article{gao_an_gould_blanco_wu_2011, title={Susceptibility of Helicoverpa armigera from different host plants in northern China to Bacillus thuringiensis toxin Cry1Ac}, volume={30}, ISSN={["1873-6904"]}, DOI={10.1016/j.cropro.2011.08.004}, abstractNote={Abstract Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) is a serious pest of cotton and many other crops in northern China. To evaluate the contribution of alternative hosts as an effective refuge for transgenic cotton expressing the Bacillus thuringiensis (Bt) Cry1Ac toxin, the susceptibility to this toxin was measured in progeny derived from field-collected H. armigera larvae and pupae from different hosts in the Xiajin’s region of the Shandong Province in northern China. During 2008–2010, progeny from a total of 258,56,184 and 160 single-pair crosses derived from wheat (first-generation), Bt cotton (second-generation), Bt cotton (third-generation), and corn (third-generation) were screened on Cry1Ac diets, respectively. Based on relative average development rates (RADR) of H. armigera larvae in these F1 tests, the second and third-generation moths emerging from Bt cotton fields were more tolerant to the Bt toxin than the first and third-generation moths emerging from wheat and corn each year. These results suggest that there is significant variation in susceptibility to Bt toxins among H. armigera populations derived from different host crops. Alternate crops, such as corn, that maintain Bt susceptible populations of H. armigera could be used as refugia to minimize the evolution of resistance to Bt cotton.}, number={11}, journal={CROP PROTECTION}, author={Gao, Yulin and An, Jingjie and Gould, Fred and Blanco, Carlos A. and Wu, Kongming}, year={2011}, month={Nov}, pages={1421–1424} }
 @article{soques_vasquez_grozinger_gould_2010, title={Age and Mating Status Do Not Affect Transcript Levels of Odorant Receptor Genes in Male Antennae of Heliothis virescens and Heliothis subflexa}, volume={36}, ISSN={["0098-0331"]}, DOI={10.1007/s10886-010-9863-6}, number={11}, journal={JOURNAL OF CHEMICAL ECOLOGY}, author={Soques, Stephanie and Vasquez, Gissella M. and Grozinger, Christina M. and Gould, Fred}, year={2010}, month={Nov}, pages={1226–1233} }
 @article{wang_vásquez_schal_zwiebel_gould_2010, title={Functional characterization of pheromone receptors in the tobacco budworm Heliothis virescens}, volume={20}, ISSN={0962-1075}, url={http://dx.doi.org/10.1111/j.1365-2583.2010.01045.x}, DOI={10.1111/j.1365-2583.2010.01045.x}, abstractNote={Functional analyses of candidate Heliothis virescens pheromone odorant receptors (HvORs) were conducted using heterologous expression in Xenopus oocytes. HvOR6 was found to be highly tuned to Z9-14:Ald, while HvOR13, HvOR14 and HvOR16 showed specificity for Z11-16:Ald, Z11-16:OAc and Z11-16:OH, respectively. HvOR15, which had been considered a candidate receptor for Z9-14:Ald did not respond to any of the pheromone compounds tested, nor to 50 other general odorants. Thus, while HvOR15 is specifically expressed in H. virescens male antennae, its role in pheromone reception remains unknown. Based on our results and previous research we can now assign pheromone receptors in H. virescens males to each of the critical H. virescens agonistic pheromone compounds and two antagonistic compounds produced by heterospecific females.}, number={1}, journal={Insect Molecular Biology}, publisher={Wiley}, author={Wang, G. and Vásquez, G. M. and Schal, C. and Zwiebel, L. J. and Gould, F.}, year={2010}, month={Oct}, pages={125–133} }
 @article{huang_lloyd_legros_gould_2010, title={Gene-drive into insect populations with age and spatial structure: a theoretical assessment}, volume={4}, ISSN={1752-4571}, url={http://dx.doi.org/10.1111/j.1752-4571.2010.00153.x}, DOI={10.1111/j.1752-4571.2010.00153.x}, abstractNote={The potential benefits and risks of genetically engineered gene-drive systems for replacing wild pest strains with more benign strains must be assessed prior to any field releases. We develop a computer simulation model to assess the feasibility of using engineered underdominance constructs to drive transgenes into age- and spatially structured mosquito populations. Our practical criterion for success is the achievement of a transgene frequency of at least 0.80 within 3 years of release. The impacts of a number of parameters that may affect the success of gene-drive, such as the release area, release age, density-dependent larval survival, fitness cost of the engineered genes, and migration probability of adults, are examined. Results show that patchy release generally requires the release of fewer engineered insects to achieve success than central release. When the fitness cost is very low, central release covering 25% of the total area can be more effective than a completely uniform release over the whole area. This study demonstrates that to determine the best method of spatial release, and the total number of engineered insects that must be released, it is important to take into account the age and sex of the released insects and spatial structure of the population.}, number={3}, journal={Evolutionary Applications}, publisher={Wiley}, author={Huang, Yunxin and Lloyd, Alun L. and Legros, Mathieu and Gould, Fred}, year={2010}, month={Sep}, pages={415–428} }
 @article{jongsma_gould_legros_yang_loon_dicke_2010, title={Insect oviposition behavior affects the evolution of adaptation to Bt crops: consequences for refuge policies}, volume={24}, ISSN={["0269-7653"]}, DOI={10.1007/s10682-010-9368-3}, abstractNote={The major lepidopteran insect pests of cotton and maize harbor intra-specific variation for behavior determining the selection of host plants for oviposition. Yet, the consequences of behavioral adaptation for fitness have neither been modeled nor monitored for Bt cotton and maize crops, the most widely grown transgenic herbivore-resistant plants. Here, we present a general two-locus heuristic model to examine potential outcomes of natural selection when pest populations initially have low frequencies of alleles for both physiological and behavioral adaptation to Bt crops. We demonstrate that certain ecological conditions allow for the evolution of behavioral choices favoring alternative oviposition hosts that limit the increase in resistance alleles, even when they are phenotypically dominant. These results have implications for current refuge policies, which should be adapted to promote the evolution of certain behavioral choices for alternative oviposition hosts in addition to dilution of physiological resistance alleles. Collection of data on oviposition host preference as a component of monitoring schemes will provide important insights into mechanisms underlying the durability of Bt-transgenic host-plant resistance.}, number={5}, journal={EVOLUTIONARY ECOLOGY}, author={Jongsma, Maarten A. and Gould, Fred and Legros, Mathieu and Yang, Limei and Loon, Joop J. A. and Dicke, Marcel}, year={2010}, month={Sep}, pages={1017–1030} }
 @article{ward_su_huang_lloyd_gould_hay_2010, title={Medea selfish genetic elements as tools for altering traits of wild populations: A theoretical analysis.}, volume={65}, ISSN={0014-3820}, url={http://dx.doi.org/10.1111/j.1558-5646.2010.01186.x}, DOI={10.1111/j.1558-5646.2010.01186.x}, abstractNote={One strategy for controlling transmission of insect-borne disease involves replacing the native insect population with transgenic animals unable to transmit disease. Population replacement requires a drive mechanism to ensure the rapid spread of linked transgenes, the presence of which may result in a fitness cost to carriers. Medea selfish genetic elements have the feature that when present in a female, only offspring that inherit the element survive, a behavior that can lead to spread. Here, we derive equations that describe the conditions under which Medea elements with a fitness cost will spread, and the equilibrium allele frequencies are achieved. Of particular importance, we show that whenever Medea spreads, the non-Medea genotype is driven out of the population, and we estimate the number of generations required to achieve this goal for Medea elements with different fitness costs and male-only introduction frequencies. Finally, we characterize two contexts in which Medea elements with fitness costs drive the non-Medea allele from the population: an autosomal element in which not all Medea-bearing progeny of a Medea-bearing mother survive, and an X-linked element in species in which X/Y individuals are male. Our results suggest that Medea elements can drive population replacement under a wide range of conditions.}, number={4}, journal={Evolution}, publisher={Wiley}, author={Ward, Catherine M. and Su, Jessica T. and Huang, Yunxin and Lloyd, Alun L. and Gould, Fred and Hay, Bruce A.}, year={2010}, month={Dec}, pages={1149–1162} }
 @article{feng_gould_huang_jiang_wu_2010, title={Modeling the population dynamics of cotton bollworm Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) over a wide area in northern China}, volume={221}, ISSN={["1872-7026"]}, DOI={10.1016/j.ecolmodel.2010.04.003}, abstractNote={The cotton bollworm Helicoverpa armigera (Lepidoptera: Noctuidae) is one of the most serious crop pests in northern China, calling for accurate prediction of pest outbreaks and strategies for pest control. A computer model is developed to simulate the population dynamics of H. armigera over a wide area in northern China. The area considered covers 12 provinces where serious outbreaks of H. armigera have been observed. In this model, pest development is driven by local ambient temperature, and adults migrate long distances between regions and select preferred hosts for oviposition within a region. Six types of host including cotton, wheat, corn, peanut, soybean and a single category composed of all other minor hosts are considered in this model. Survival rates of eggs and larvae are based on life-table data, and simulated as a function of host type, host phenology and temperature. The incidence of diapause depends on temperature and photoperiod experienced during the larval stage. Survival rate of non-diapause pupae is a nonlinear function of rainfall, and overwinter survival rate is a nonlinear function of temperature. Insecticide is applied when population density exceeds the economic threshold on a host crop within a region. Comparisons of model output with light-trap data indicate that our model reflects the pest population dynamics over a wide area, and could potentially be used for testing novel pest control strategies in northern China.}, number={15}, journal={ECOLOGICAL MODELLING}, author={Feng, Hongqiang and Gould, Fred and Huang, Yunxin and Jiang, Yuying and Wu, Kongming}, year={2010}, month={Jul}, pages={1819–1830} }
 @article{blanco_gould_groot_abel_hernandez_perera_teran-vargas_2010, title={Offspring From Sequential Matings Between Bacillus thuringiensis-Resistant and Bacillus thuringiensis-Susceptible Heliothis virescens Moths (Lepidoptera: Noctuidae)}, volume={103}, ISSN={["1938-291X"]}, DOI={10.1603/ec09232}, abstractNote={The tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), is an economically important pest of the Americas. Females of this species copulate multiple times during their lifetimes, and the presence of sperm from multiple males inside them could allow for a diversity of paternal genotypes in the offspring, unless there was complete precedence of sperm from the first mating. If a female copulates with a male that is insecticide-susceptible and another male that is insecticide-resistant, her progeny could vary in their resistance phenotypes. In some cases, this could impact the evolution of insecticide resistance in a population. We designed a series of experiments to determine whether Bacillus thuringiensis susceptibility is maintained when an H. virescens female that is homozygous for a genetically recessive form of B. thuringiensis resistance copulates with a Cry1Ac-susceptible and a Cry1Ac-resistant males. During the lifetime of double-copulated females, a proportion of F1 progeny were Cry1Ac-resistant. This indicates that when a B. thuringiensis-resistant H. virescens female copulates with two males, with one male being resistant to Cry1Ac, some of the progeny will carry resistance to this insecticide. Due to the polyandrous nature of this species, the above-mentioned scenario is not unrealistic; therefore, results from this study may help understand and manage the evolution of B. thuringiensis-resistance in field populations.}, number={3}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Blanco, Carlos A. and Gould, Fred and Groot, Astrid T. and Abel, Craig A. and Hernandez, Gerardo and Perera, O. P. and Teran-Vargas, Antonio P.}, year={2010}, month={Jun}, pages={861–868} }
 @article{gould_estock_hillier_powell_groot_ward_emerson_schal_vickers_2010, title={Sexual isolation of male moths explained by a single pheromone response QTL containing four receptor genes}, volume={107}, ISSN={["0027-8424"]}, DOI={10.1073/pnas.0910945107}, abstractNote={Long distance sexual communication in moths has fascinated biologists because of the complex, precise female pheromone signals and the extreme sensitivity of males to specific pheromone molecules. Progress has been made in identifying some genes involved in female pheromone production and in male response. However, we have lacked information on the genetic changes involved in evolutionary diversification of these mate-finding mechanisms that is critical to understanding speciation in moths and other taxa. We used a combined quantitative trait locus (QTL) and candidate gene approach to determine the genetic architecture of sexual isolation in males of two congeneric moths, Heliothis subflexa and Heliothis virescens. We report behavioral and neurophysiological evidence that differential male responses to three female-produced chemicals (Z9-14:Ald, Z9-16:Ald, Z11-16:OAc) that maintain sexual isolation of these species are all controlled by a single QTL containing at least four odorant receptor genes. It is not surprising that pheromone receptor differences could control H. subflexa and H. virescens responses to Z9-16:Ald and Z9-14:Ald, respectively. However, central rather than peripheral level control over the positive and negative responses of H. subflexa and H. virescens to Z11-16:OAc had been expected. Tight linkage of these receptor genes indicates that mutations altering male response to complex blends could be maintained in linkage disequilibrium and could affect the speciation process. Other candidate genes such as those coding for pheromone binding proteins did not map to this QTL, but there was some genetic evidence of a QTL for response to Z11-16:OH associated with a sensory neuron membrane protein gene.}, number={19}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Gould, Fred and Estock, Marie and Hillier, N. Kirk and Powell, Bekah and Groot, Astrid T. and Ward, Catherine M. and Emerson, Jennifer L. and Schal, Coby and Vickers, Neil J.}, year={2010}, month={May}, pages={8660–8665} }
 @article{xu_legros_gould_lloyd_2010, title={Understanding Uncertainties in Model-Based Predictions of Aedes aegypti Population Dynamics}, volume={4}, ISSN={1935-2735}, url={http://dx.doi.org/10.1371/journal.pntd.0000830}, DOI={10.1371/journal.pntd.0000830}, abstractNote={Aedes aegypti is one of the most important mosquito vectors of human disease. The development of spatial models for Ae. aegypti provides a promising start toward model-guided vector control and risk assessment, but this will only be possible if models make reliable predictions. The reliability of model predictions is affected by specific sources of uncertainty in the model.This study quantifies uncertainties in the predicted mosquito population dynamics at the community level (a cluster of 612 houses) and the individual-house level based on Skeeter Buster, a spatial model of Ae. aegypti, for the city of Iquitos, Peru. The study considers two types of uncertainty: 1) uncertainty in the estimates of 67 parameters that describe mosquito biology and life history, and 2) uncertainty due to environmental and demographic stochasticity. Our results show that for pupal density and for female adult density at the community level, respectively, the 95% prediction confidence interval ranges from 1000 to 3000 and from 700 to 5,000 individuals. The two parameters contributing most to the uncertainties in predicted population densities at both individual-house and community levels are the female adult survival rate and a coefficient determining weight loss due to energy used in metabolism at the larval stage (i.e. metabolic weight loss). Compared to parametric uncertainty, stochastic uncertainty is relatively low for population density predictions at the community level (less than 5% of the overall uncertainty) but is substantially higher for predictions at the individual-house level (larger than 40% of the overall uncertainty). Uncertainty in mosquito spatial dispersal has little effect on population density predictions at the community level but is important for the prediction of spatial clustering at the individual-house level.This is the first systematic uncertainty analysis of a detailed Ae. aegypti population dynamics model and provides an approach for identifying those parameters for which more accurate estimates would improve model predictions.}, number={9}, journal={PLoS Neglected Tropical Diseases}, publisher={Public Library of Science (PLoS)}, author={Xu, Chonggang and Legros, Mathieu and Gould, Fred and Lloyd, Alun L.}, editor={O'Neill, ScottEditor}, year={2010}, month={Sep}, pages={e830} }
 @article{an_gao_wu_gould_gao_shen_lei_2010, title={Vip3Aa Tolerance Response of Helicoverpa armigera Populations From a Cry1Ac Cotton Planting Region}, volume={103}, ISSN={["1938-291X"]}, DOI={10.1603/ec10105}, abstractNote={Transgenic cotton, Gossypium hirsutum L., that expresses the Bacillus thuringiensis (Bt) Cry1Ac toxin, holds great promise in controlling target insect pests. Evolution of resistance by target pests is the primary threat to the continued efficacy of Bt cotton. To thwart pest resistance evolution, a transgenic cotton culitvar that produces two different Bt toxins, cry1Ac and vip3A genes, was proposed as a successor of cry1Ac cotton. This article reports on levels of Vip3Aa tolerance in Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) populations from the Cry1Ac cotton planting region in China based on bioassays of the F1 generation of isofemale lines. In total, 80 isofemale families of H. armigera from Xiajin county of Shandong Province (an intensive Bt cotton planting area) and 93 families from Anci county of Hebei Province (a multiple-crop system including corn [Zea mays L.] , soybean [Glycine max (L.) Merr.], peanut (Arachis hypogaea L.), and Bt cotton) were screened with a discriminating concentration of both Cry1Ac- and Vip3A-containing diets in 2009. From data on the relative average development rates and percentage of larval weight inhibition of F1 full-sib families tested simultaneously on Cry1Ac and Vip3Aa, results indicate that responses to Cry1Ac and Vip3Aa were not genetically correlated in field population ofH. armigera. This indicates that the threat of cross-resistance between Cry1Ac and Vip3A is low in field populations of H. armigera. Thus, the introduction of Vip3Aa/Cry1Ac-producing lines could delay resistance evolution in H. armigera in Bt cotton planting area of China.}, number={6}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={An, Jingjie and Gao, Yulin and Wu, Kongming and Gould, Fred and Gao, Jianhua and Shen, Zhicheng and Lei, Chaoliang}, year={2010}, month={Dec}, pages={2169–2173} }
 @article{gao_wu_gould_shen_2009, title={Cry2Ab Tolerance Response of Helicoverpa armigera (Lepidoptera: Noctuidae) Populations From Cry1Ac Cotton Planting Region}, volume={102}, ISSN={["1938-291X"]}, DOI={10.1603/029.102.0347}, abstractNote={Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is an important lepidopteran pest of cotton, Gossypium hirsutum L., in Asia. Transgenic cotton expressing the cry1Ac gene from Bacillus thuringiensis (Bt) has been widely planted for control of this pest. For managing the potential risk from resistance evolution in this pest, a new transgenic Bt cotton containing cry1Ac and cry2Ab genes (gene pyramided strategy) was designed as a successor of cry1Ac cotton. This article reports on levels of Cry2Ab tolerance in H. armigera populations from CrylAc cotton planting region in China based on bioassays of F1 and F2 offspring of isofemale lines. In total, 572 isofemale families of H. armigera from Xiajin County of Shandong Province (an intensive Bt cotton-planting area) and 124 families from Anci County of Hebei Province [a multiple-crop system, including corn (Zea mays L.), soybean (Gycine max (L.) Merr., peanut (Arachis spp.), and Bt cotton] were screened with both Cry1Ac- and Cry2Ab-containing diets in 2008. The bioassays results indicated that relative average development rates (RADR) of F1 full-sib families from field-collected female moths on Cry1Ac- and Cry2Ab-containing diet were positively correlated. The same correlation was found in the F2 generation, indicating cross-tolerance between Cry1Ac and Cry2Ab in field populations of H. armigera in Yellow River cotton-farming region of China. This cross-tolerance must be considered in evaluating the utility of pyramiding Bt genes in cotton for delaying evolution of resistance.}, number={3}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Gao, Yulin and Wu, Kongming and Gould, Fred and Shen, Zhicheng}, year={2009}, month={Jun}, pages={1217–1223} }
 @article{legros_lloyd_huang_gould_2009, title={Density-Dependent Intraspecific Competition in the Larval Stage of Aedes aegypti (Diptera: Culicidae): Revisiting the Current Paradigm}, volume={46}, ISSN={["0022-2585"]}, DOI={10.1603/033.046.0301}, abstractNote={Density-dependent intraspecific competition has been considered an important determinant of the dynamics of larval stages of Aedes aegypti. A model was published in 1984 providing a mathematical description of this density dependence, based on field data, that has since been widely used. This description, however, is based on the strong assumption that all mortality is density-dependent. We re-examine the data without this premise and find a reduced importance of density dependence, as well as a different functional form. Based on these discrepancies, we emphasize that the characterization of density dependence in the larval stages of Ae. aegypti should be based on a more complete dataset, and we use artificially generated data to explore how such additional information could help developing a better description of this density dependence. We review other empirical studies on larval competition, discuss the need for further dedicated studies, and provide a few simple guidelines for the design of such studies.}, number={3}, journal={JOURNAL OF MEDICAL ENTOMOLOGY}, author={Legros, Mathieu and Lloyd, Alun L. and Huang, Yunxin and Gould, Fred}, year={2009}, month={May}, pages={409–419} }
 @article{petzold_brownie_gould_2009, title={Effect of Heliothis subflexa herbivory on fruit abscission by Physalis species: the roles of mechanical damage and chemical factors}, volume={34}, ISSN={["1365-2311"]}, DOI={10.1111/j.1365-2311.2009.01109.x}, abstractNote={. 

1. Insect oral secretions are important for the induction of a number of plant responses, but the relative role of mechanical damage in the induction of these responses is often not well understood. Damage from the frugivore Heliothis subflexa, a specialist on Physalis species, causes herbivore-induced fruit abscission. In this field study, we examined the separate and combined effects of mechanical damage and H. subflexa oral secretions on Physalis fruit abscission.



2. To determine the relative role of mechanical and chemical factors, the following treatments were administered to fruit: (1) three levels of mechanical damage, (2) natural herbivore damage by control larvae and by larvae surgically treated to inhibit saliva secretion, and (3) injection of H.subflexa oral secretions and a water control. Abscission of mechanically damaged fruit with and without the addition of oral secretions was also compared.



3. Mechanical damage was sufficient to cause fruit abscission, and the addition of oral secretions to mechanically damaged fruit did not cause an increase in fruit abscission. Normal caterpillars and those treated to inhibit saliva secretion caused similar abscission rates.



4. Though most studies examining the effects of insect oral secretions on induced plant responses find these chemical stimuli to be important or essential, the results of the present study showed that oral secretions are not necessary for fruit abscission. Future work is needed to determine the relative importance of mechanical damage in herbivore-induced plant responses in other systems.}, number={5}, journal={ECOLOGICAL ENTOMOLOGY}, author={Petzold, Jennifer and Brownie, Cavell and Gould, Fred}, year={2009}, month={Oct}, pages={603–613} }
 @article{gao_wu_gould_2009, title={Frequency of Bt Resistance Alleles in H-armigera During 2006-2008 in Northern China}, volume={38}, ISSN={["1938-2936"]}, DOI={10.1603/022.038.0445}, abstractNote={Helicoverpa armigera is an important lepidopteran pest of cotton in China. From 2002, the frequency of Bt resistance alleles and quantitative shifts in larval Cry1Ac tolerance of field H. armigera population were monitored using bioassays of F(1) and F(2) offspring of isofemale lines from Xiajin County of Shandong Province (an intensive Bt cotton planting area) and Anci County of Hebei Province (a multiple-crop system including corn, soybean, peanut, and Bt cotton) in northern China. During 2006-2008, a total of 2,306 isofemale lines from the Xiajin population and a total of 1,270 isofemale lines from the Anci population were successfully screened on Cry1Ac diets. For each year, it was estimated that the major resistance gene frequency in Xiajin population in 2006, 2007, and 2008 was 0, 0.00022, and 0.00033, respectively. No major alleles conferring resistance to Cry1Ac were found in the Anci population; the frequency of resistance alleles for Cry1Ac was 0. Based on the relative average development rates (RADRs) of H. armigera larvae in F(1) tests, no substantial increase in Cry1Ac tolerance was found in either location over the 3-yr period. There were also significantly positive correlations between RADR of lines in the F(1) generation and the RADR of their F(2) offspring, indicating genetic variation in response to toxin. The low frequency of resistance alleles found in this study and in our previous results from 2002 to 2005 suggest the frequency of resistance alleles has remained low and that natural refugia resistance management strategy maybe effective for delaying resistance evolution in H. armigera to Bt cotton in northern China.}, number={4}, journal={ENVIRONMENTAL ENTOMOLOGY}, author={Gao, Yulin and Wu, Kongming and Gould, Fred}, year={2009}, month={Aug}, pages={1336–1342} }
 @article{benda_brownie_schal_gould_2009, title={Fruit abscission by Physalis species as defense against frugivory}, volume={130}, ISSN={["1570-7458"]}, DOI={10.1111/j.1570-7458.2008.00792.x}, abstractNote={Fruit abscission as a response to herbivory is well-documented in many plant species, but its effect on further damage by mobile herbivores that survive fruit abscission is relatively unstudied. Physalis plants (Solanaceae) abscise fruit containing feeding larvae of their main frugivore, Heliothis subflexa Guenee (Lepidoptera: Noctuidae), a specialist moth. We tested the ability of H. subflexa larvae placed under the plant canopy to find and climb onto two architecturally different Physalis species. Physalis pubescens L., a low, shrub-like, spreading plant, abscises its fruit at a higher rate than Physalis angulata L., a tall arborescent plant. As a result, small larvae are more often dropped from P. pubescens . Third and fifth instars located P. pubescens faster and with a higher probability than P. angulata . Although fifth instars outperformed third-instar caterpillars at finding P. angulata , P. pubescens was located equally fast by the two instars. Heliothis subflexa located Physalis plants more successfully and more quickly than a close relative, the generalist Heliothis virescens Fabricius. The higher fruit abscission rates in P. pubescens may be an evolved response to its greater susceptibility to searching caterpillars.}, number={1}, journal={ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA}, author={Benda, Nicole D. and Brownie, Cavell and Schal, Coby and Gould, Fred}, year={2009}, month={Jan}, pages={21–27} }
 @misc{groot_inglis_bowdridge_santangelo_blanco_lopez_teran vargas_gould_schal_2009, title={GEOGRAPHIC AND TEMPORAL VARIATION IN MOTH CHEMICAL COMMUNICATION}, volume={63}, ISSN={["1558-5646"]}, DOI={10.1111/j.1558-5646.2009.00702.x}, abstractNote={In moth pheromone communication signals, both quantitative and qualitative intraspecific differences have been found across geographic regions. Such variation has generally been hypothesized to be due to selection, but evidence of genetic control of these differences is largely lacking. To explore the patterns of variation in pheromone signals, we quantified variation in the female sex pheromone blend and male responses of two closely related noctuid moth species in five different geographic regions for 2-3 consecutive years. We found significant variation in the ratios of sex pheromone blend components as well as in male response, not only between geographic regions but also within a region between consecutive years. The temporal variation was of a similar magnitude as the geographic variation. As far as we know, this is the first study reporting such temporal variation in moth chemical communication systems. The geographic variation seems to at least partly be controlled by genetic factors, and to be correlated with the quality of the local chemical environment. However, the pattern of temporal variation within populations suggests that optimization of the pheromonal signal also may be driven by within-generation physiological adjustments by the moths in response to their experience of the local chemical environment.}, number={8}, journal={EVOLUTION}, author={Groot, Astrid T. and Inglis, Olive and Bowdridge, Scott and Santangelo, Richard G. and Blanco, Carlos and Lopez, Juan D., Jr. and Teran Vargas, Antonio and Gould, Fred and Schal, Coby}, year={2009}, month={Aug}, pages={1987–2003} }
 @article{huang_lloyd_legros_gould_2009, title={Gene-drive in age-structured insect populations}, volume={2}, ISSN={1752-4571 1752-4571}, url={http://dx.doi.org/10.1111/j.1752-4571.2008.00049.x}, DOI={10.1111/j.1752-4571.2008.00049.x}, abstractNote={To date, models of gene-drive mechanisms proposed for replacing wild-type mosquitoes with transgenic strains that cannot transmit diseases have assumed no age or mating structure. We developed a more detailed model to analyze the effects of age and mating-related factors on the number of engineered insects that must be introduced into a wild population to achieve successful gene-drive based on the Medea and engineered underdominance mechanisms. We found that models without age-structure and mating details can substantially overestimate or underestimate the numbers of engineered insects that must be introduced. In general, introduction thresholds are lowest when young adults are introduced. When both males and females are introduced, assortative mating by age has little impact on the introduction threshold unless the introduced females have diminished reproductive ability because of their age. However, when only males are introduced, assortative mating by age is generally predicted to increase introduction thresholds. In most cases, introduction thresholds are much higher for male-only introductions than for both-sex introductions, but when mating is nearly random and the introduced insects are adults with Medea constructs, male-only introductions can have somewhat lower thresholds than both-sex introductions. Results from this model suggest specific parameters that should be measured in field experiments.}, number={2}, journal={Evolutionary Applications}, publisher={Wiley}, author={Huang, Yunxin and Lloyd, Alun L. and Legros, Mathieu and Gould, Fred}, year={2009}, month={May}, pages={143–159} }
 @article{groot_estock_horovitz_hamilton_santangelo_schal_gould_2009, title={QTL analysis of sex pheromone blend differences between two closely related moths: Insights into divergence in biosynthetic pathways}, volume={39}, ISSN={["1879-0240"]}, DOI={10.1016/j.ibmb.2009.05.002}, abstractNote={To understand the evolution of premating signals in moths, it is important to know the genetic basis of these signals. We conducted Quantitative Trait Locus (QTL) analysis by hybridizing two noctuid moth species, Heliothis virescens (Hv) and Heliothis subflexa (Hs), and backcrossing the F(1) females to males of both parental species. One of these backcrosses (F(1) x Hs) was a biological replicate of our previous study (Sheck et al., 2006) and served to test the robustness of our previous findings. The backcross to Hv was designed to reveal QTL with recessive inheritance of the Hv character state. This study confirms previously discovered QTL, but also reports new QTL. Most importantly, we found relatively large QTL affecting Z9-16:Ald, the critical sex pheromone component of Hs. For Z9-14:Ald, the critical sex pheromone component of Hv, as well as for the minor pheromone compound 14:Ald, we found QTL in which the change in pheromone ratio was opposite-to-expected. Linking QTL to the biosynthetic pathways of the pheromone compounds of Hv and Hs implicates several candidate genes in the divergence of these premating signals, the most important of which are acetyl transferase, one or more desaturase(s), and a fatty acyl reductase or alcohol oxidase.}, number={8}, journal={INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY}, author={Groot, Astrid T. and Estock, Marie L. and Horovitz, Joy L. and Hamilton, Jennifer and Santangelo, Richard G. and Schal, Coby and Gould, Fred}, year={2009}, month={Aug}, pages={568–577} }
 @article{blanco_gould_vega-aquino_jurat-fuentes_perera_abel_2009, title={Response of Heliothis virescens (Lepidoptera: Noctuidae) Strains to Bacillus thuringiensis Cry1Ac Incorporated Into Different Insect Artificial Diets}, volume={102}, ISSN={["1938-291X"]}, DOI={10.1603/029.102.0426}, abstractNote={Susceptibility to the Cry1Ac toxin from Bacillus thuringiensis in tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), is usually measured by performing bioassays under laboratory conditions. Accurate comparison of Cry1Ac susceptibility among H. virescens samples conducted in different places is challenged by several important methodological aspects, especially if different insect artificial diets are used to perform bioassays. In this study, we compared Cry1Ac susceptibility of four different-origin H. virescens colonies when challenged with this toxin incorporated into four different insect artificial diets. Our data show that Cry1Ac susceptibility was lower in all the H. virescens colonies for one of the commercial diets (Bio-Serv). Bio-Serv diet was one of the least significantly consumed diets by larvae of the four different colonies, which indicates that insects encountered less Cry1Ac toxin due to lower consumption of diet. Larvae fed Bio-Serv diet also seemed to display slower Cry1Ac toxin activation compared with larvae fed any of the other three diets tested. In contrast, a wheat germ-soybean diet (ARS) was one of the most consumed diets by the four H. virescens colonies. The increased consumption of ARS diet probably led to the high level of Cry1Ac susceptibility observed in all the H. virescens colonies. Our data highlight the importance of using common diets and use a standard tobacco budworm colony when comparing Cry1Ac susceptibility between diverse H. virescens strains or across time.}, number={4}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Blanco, Carlos A. and Gould, Fred and Vega-Aquino, Paulina and Jurat-Fuentes, Juan Luis and Perera, O. P. and Abel, Craig A.}, year={2009}, month={Aug}, pages={1599–1606} }
 @article{magori_legros_puente_focks_scott_lloyd_gould_2009, title={Skeeter Buster: A Stochastic, Spatially Explicit Modeling Tool for Studying Aedes aegypti Population Replacement and Population Suppression Strategies}, volume={3}, ISSN={1935-2735}, url={http://dx.doi.org/10.1371/journal.pntd.0000508}, DOI={10.1371/journal.pntd.0000508}, abstractNote={Background Dengue is the most important mosquito-borne viral disease affecting humans. The only prevention measure currently available is the control of its vectors, primarily Aedes aegypti. Recent advances in genetic engineering have opened the possibility for a new range of control strategies based on genetically modified mosquitoes. Assessing the potential efficacy of genetic (and conventional) strategies requires the availability of modeling tools that accurately describe the dynamics and genetics of Ae. aegypti populations. Methodology/Principal findings We describe in this paper a new modeling tool of Ae. aegypti population dynamics and genetics named Skeeter Buster. This model operates at the scale of individual water-filled containers for immature stages and individual properties (houses) for adults. The biology of cohorts of mosquitoes is modeled based on the algorithms used in the non-spatial Container Inhabiting Mosquitoes Simulation Model (CIMSiM). Additional features incorporated into Skeeter Buster include stochasticity, spatial structure and detailed population genetics. We observe that the stochastic modeling of individual containers in Skeeter Buster is associated with a strongly reduced temporal variation in stage-specific population densities. We show that heterogeneity in container composition of individual properties has a major impact on spatial heterogeneity in population density between properties. We detail how adult dispersal reduces this spatial heterogeneity. Finally, we present the predicted genetic structure of the population by calculating FST values and isolation by distance patterns, and examine the effects of adult dispersal and container movement between properties. Conclusions/Significance We demonstrate that the incorporated stochasticity and level of spatial detail have major impacts on the simulated population dynamics, which could potentially impact predictions in terms of control measures. The capacity to describe population genetics confers the ability to model the outcome of genetic control methods. Skeeter Buster is therefore an important tool to model Ae. aegypti populations and the outcome of vector control measures.}, number={9}, journal={PLoS Neglected Tropical Diseases}, publisher={Public Library of Science (PLoS)}, author={Magori, Krisztian and Legros, Mathieu and Puente, Molly E. and Focks, Dana A. and Scott, Thomas W. and Lloyd, Alun L. and Gould, Fred}, editor={Kittayapong, PattamapornEditor}, year={2009}, month={Sep}, pages={e508} }
 @article{gould_huang_legros_lloyd_2008, title={A Killer-Rescue system for self-limiting gene drive of anti-pathogen constructs}, volume={275}, ISSN={["0962-8452"]}, url={https://publons.com/publon/8709314/}, DOI={10.1098/rspb.2008.0846}, abstractNote={A number of genetic mechanisms have been suggested for driving anti-pathogen genes into natural populations. Each of these mechanisms requires complex genetic engineering, and most are theoretically expected to permanently spread throughout the target species' geographical range. In the near term, risk issues and technical limits of molecular methods could delay the development and use of these mechanisms. We propose a gene-drive mechanism that can be self-limiting over time and space, and is simpler to build. This mechanism involves one gene that codes for toxicity (killer) and a second that confers immunity to the toxic effects (rescue). We use population-genetic models to explore cases with one or two independent insertions of the killer gene and one insertion of the rescue gene. We vary the dominance and penetrance of gene action, as well as the magnitude of fitness costs. Even with the fitness costs of 10 per cent for each gene, the proportion of mosquitoes expected to transmit the pathogen decreases below 5 per cent for over 40 generations after one 2 : 1 release (engineered : wild) or after four 1 : 2 releases. Both the killer and rescue genes will be lost from the population over time, if the rescue construct has any associated fitness cost. Molecular approaches for constructing strains are discussed.}, number={1653}, journal={PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES}, publisher={The Royal Society}, author={Gould, Fred and Huang, Yunxin and Legros, Mathieu and Lloyd, Alun L.}, year={2008}, month={Dec}, pages={2823–2829} }
 @article{blanco_perera_gould_sumerford_hernandez_abel_andow_2008, title={An empirical test of the F(2) screen for detection of Bacillus thuringiensis-resistance alleles in tobacco budworm (Lepidoptera : Noctuidae)}, volume={101}, ISSN={["0022-0493"]}, DOI={10.1603/0022-0493(2008)101[1406:AETOTF]2.0.CO;2}, abstractNote={Insects exposed to genetically modified crops expressing Bacillus thuringiensis (Bt) toxins are under intense selection pressure that could result on widespread Bt resistance. Screening for early indications of Bt resistance developing in targeted Lepidoptera is conducted in many of the regions where genetically modified cotton and corn have been commercialized. Heliothis virescens (F.) (Lepidoptera: Noctuidae) has been selected in the laboratory to have a gene for resistance to Cry1Ac. We used this laboratory line to test the assumptions and theoretical predictions related to detection of recessive Bt-resistant alleles in field populations based on a second generation (F2) screen. By creating single-pair families from mating a heterozygous Cry1Ac-resistant moth with a Cry1Ac-susceptible moth, we simulated the most common genotype when Bt-resistance alleles are at low frequency in the field. The second generation (F2) neonates of single-pair families were screened daily with diagnostic concentration bioassays. Cry1Ac-resistant homozygous larvae were detected, but the proportion of resistant larvae was generally below the theoretical expectation of 6.25% and was influenced by the moth F1 sib-mating density and by the day of oviposition of F2 eggs. Logistical considerations such as F1 sib-mating density and F2 neonate screening are important for the successful implementation of a reliable method.}, number={4}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Blanco, Carlos A. and Perera, O. P. and Gould, Fred and Sumerford, Douglas V. and Hernandez, Gerardo and Abel, Craig A. and Andow, David A.}, year={2008}, month={Aug}, pages={1406–1414} }
 @article{gould_2008, title={Broadening the application of evolutionarily based genetic pest management}, volume={62}, ISSN={["1558-5646"]}, DOI={10.1111/j.1558-5646.2007.00298.x}, abstractNote={Insect- and tick-vectored diseases such as malaria, dengue fever, and Lyme disease cause human suffering, and current approaches for prevention are not adequate. Invasive plants and animals such as Scotch broom, zebra mussels, and gypsy moths continue to cause environmental damage and economic losses in agriculture and forestry. Rodents transmit diseases and cause major pre- and postharvest losses, especially in less affluent countries. Each of these problems might benefit from the developing field of Genetic Pest Management that is conceptually based on principles of evolutionary biology. This article briefly describes the history of this field, new molecular tools in this field, and potential applications of those tools. There will be a need for evolutionary biologists to interact with researchers and practitioners in a variety of other fields to determine the most appropriate targets for genetic pest management, the most appropriate methods for specific targets, and the potential of natural selection to diminish the effectiveness of genetic pest management. In addition to producing environmentally sustainable pest management solutions, research efforts in this area could lead to new insights about the evolution of selfish genetic elements in natural systems and will provide students with the opportunity to develop a more sophisticated understanding of the role of evolutionary biology in solving societal problems.}, number={2}, journal={EVOLUTION}, author={Gould, Fred}, year={2008}, month={Feb}, pages={500–510} }
 @article{puente_magori_kennedy_gould_2008, title={Impact of Herbivore-induced Plant Volatiles on Parasitoid Foraging Success: A Spatial Simulation of the Cotesia rubecula, Pieris rapae, and Brassica oleracea System}, volume={34}, ISSN={0098-0331 1573-1561}, url={http://dx.doi.org/10.1007/s10886-008-9472-9}, DOI={10.1007/s10886-008-9472-9}, number={7}, journal={Journal of Chemical Ecology}, publisher={Springer Science and Business Media LLC}, author={Puente, Molly and Magori, Krisztian and Kennedy, George G. and Gould, Fred}, year={2008}, month={Apr}, pages={959–970} }
 @article{abney_sorenson_gould_bradley_2008, title={Limitations of stable carbon isotope analysis for determining natal host origins of tobacco budworm, Heliothis virescens}, volume={126}, ISSN={["1570-7458"]}, DOI={10.1111/j.1570-7458.2007.00633.x}, abstractNote={Differences in the stable carbon isotope ratios of plants utilizing the C3 vs. C4 photosynthetic pathway have been used to broadly identify the natal host origins of herbivorous insects. This study explored whether adequate variation exists between the carbon isotope ratios of different C3 plants in the host range of Heliothis virescens (Fabricius) (Lepidoptera: Noctuidae) to enable accurate identification of natal host-plant species. Isotope ratio mass spectrometry (IRMS) analysis of 13 C/ 12 C ratios of moths reared on four crop plant species [ Gossypium hirsutum (L.) , Nicotiana tabacum L. , Glycine max (L.) Merrill, and Arachis hypogaea L.] and two common weed species [ Geranium carolinianum L. and Linaria canadensis (L.) Chaz.] revealed a range of δ 13 C values within that expected for plants utilizing the C3 photosynthetic pathway. Analysis of vegetative and reproductive tissues from the plants utilized in the study resulted in statistically different δ 13 C values for some plant species; nevertheless, the range of δ 13 C values observed for many plant species overlapped. Significant differences in mean δ 13 C values were detected between groups of moths reared on different host-plant species, but there was no significant correlation between the δ 13 C values of moths vs. the δ 13 C value of plant tissue on which they were reared. Feral tobacco budworm moths collected over 3 years were found to have carbon isotope ratios consistent with those having fed on C3 plants, confirming little utilization of C4 plant species by the insect. Results demonstrate that within the range of C3 host plants tested, carbon isotope signatures are not sufficiently unique to enable a reliable determination of natal origin of feral tobacco budworm with current IRMS technology.}, number={1}, journal={ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA}, author={Abney, M. R. and Sorenson, C. E. and Gould, F. and Bradley, J. R., Jr.}, year={2008}, month={Jan}, pages={46–52} }
 @article{puente_kennedy_gould_2008, title={The Impact of Herbivore-Induced Plant Volatiles on Parasitoid Foraging Success: A General Deterministic Model}, volume={34}, ISSN={0098-0331 1573-1561}, url={http://dx.doi.org/10.1007/s10886-008-9471-x}, DOI={10.1007/s10886-008-9471-x}, number={7}, journal={Journal of Chemical Ecology}, publisher={Springer Science and Business Media LLC}, author={Puente, Molly E. and Kennedy, George G. and Gould, Fred}, year={2008}, month={Apr}, pages={945–958} }
 @article{gahan_gould_lopez_micinski_heckel_2007, title={A polymerase chain reaction screen of field populations of Heliothis virescens for a retrotransposon insertion conferring resistance to Bacillus thuringiensis toxin}, volume={100}, ISSN={["0022-0493"]}, DOI={10.1603/0022-0493(2007)100[187:APCRSO]2.0.CO;2}, abstractNote={The evolution of pest resistance to transgenic crop plants producing insecticidal toxins from Bacillus thuringiensis (Bt) Berliner poses a continuing threat to their sustainable use in agriculture. One component of the U.S.-wide resistance management plan for Bt cotton, Gossypium hirsutum L., involves monitoring the frequency of resistance alleles in field populations. However, existing methods are expensive and may not detect recessive resistance alleles until their frequencies are too high for countermeasures to be effective; therefore, more sensitive methods are needed. The first Bt resistance-causing mutation described at the molecular level was a retrotransposon insertion into the gene encoding a 12-cadherin-domain protein expressed in the midgut of larval Heliothis virescens (F.). We report the first large-scale screen for this mutation using a polymerase chain reaction (PCR)-based approach on >7,000 field-collected individuals. The specific insertion was not detected in any of these samples, nor was it detected in three progeny-tested, field-caught males thought to carry a Bt resistance gene. Unlike the targets of many chemical insecticides where a limited number of resistance-causing mutations compatible with viability can occur; a very large number of such mutations seem possible for the 12-cadherin-domain gene. However, even if these mutations are viable in the laboratory, they may not threaten the effectiveness of transgenic crops because of a high fitness cost in the field. The challenge remains to detect the subset of possible resistance-conferring alleles that are still rare but are viable in the field and increasing due to selection by Bt cotton. This situation will complicate PCR-based Bt resistance monitoring strategies.}, number={1}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Gahan, Linda J. and Gould, Fred and Lopez, Juan D., Jr. and Micinski, Stephen and Heckel, David G.}, year={2007}, month={Feb}, pages={187–194} }
 @article{jackson_marcus_gould_bradley_van duyn_2007, title={Cross-resistance responses of Cry1Ac-selected Heliothis virescens (Lepidoptera : Noctuidae) to the Bacillus thuringiensis protein Vip3A}, volume={100}, ISSN={["0022-0493"]}, DOI={10.1603/0022-0493(2007)100[180:CROCHV]2.0.CO;2}, abstractNote={One susceptible and three Cry1Ac-resistant strains of tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), were used in laboratory studies to determine the level of cross-resistance between the Bacillus thuringiensis (Berliner) toxins Cry1Ac and Vip3A by using concentration-mortality and leaf tissue experiments. Concentration-mortality data demonstrated that the three Cry1Ac-resistant H. virescens strains, YHD2, KCBhyb, and CxC, were at least 215- to 316-fold resistant to Cry1Ac compared with the susceptible strain, YDK. Results from Vip3A concentration-mortality tests indicated that mortality was similar among all four H. virescens strains. Relative larval growth on Cry1Ac reflected concentration-mortality test results, because YHD2 larval growth was mostly unaffected by the Cry1Ac concentrations tested. Growth ratios for KCBhyb and CXC indicated that they had a more moderate level of resistance to Cry1Ac than did YHD2. Relative larval growth on Vip3A was highly variable at lower concentrations, but it was more consistent on concentrations of Vip3A above 25 microg/ml. Differences in larval growth among strains on Vip3A were not as pronounced as seen in Cry1Ac experiments. Mortality and larval growth also was assessed in leaf tissue bioassays in which YDK, CxC, and KCBhyb neonates were placed onto leaf disks from non-Bt and Bt cotton, Gossypium hirsutum L., for 5 d. Three Bt lines were used in an initial bioassay and consisted of two Vip3A-containing lines, COT203 and COT102, and a Cry1Ac-producing line. Mortality of KCBhyb and CXC was lower than that of YDK larvae in the presence of leaf tissue from the Cry1Ac-producing line. Additionally, increased larval growth and leaf tissue consumption on Cry1Ac-containing leaf disks was observed for KCBhyb and CXC. Mortality and larval weights were similar among strains when larvae were fed leaf tissue of either non-Bt, COT203, or COT102. A subsequent leaf tissue bioassay was conducted that evaluated four cotton lines: non-Bt, Cry1Ab-expressing, Vip3A-expressing, and pyramided-toxin plants that produced both Cry1Ab and Vip3A. Mortality levels were similar among strains when fed non-Bt, Vip3A-expressing, or pyramided-toxin leaf tissues. Mortality was higher for YDK than for KCBhyb or CXC on Cry1Ab-expressing leaf tissues. No differences in larval weights were observed among strains for any genotype tested. Results of these experiments demonstrate that cross-resistance is nonexistent between CrylAc and Vip3A in H. virescens. Thus, the introduction of Vip3A-producing lines could delay Cry1Ac-resistance evolution in H. virescens, if these lines gain a significant share of the market.}, number={1}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Jackson, R. E. and Marcus, M. A. and Gould, F. and Bradley, J. R., Jr. and Van Duyn, J. W.}, year={2007}, month={Feb}, pages={180–186} }
 @article{groot_santangelo_ricci_brownie_gould_schal_2007, title={Differential attraction of Heliothis subflexa males to synthetic pheromone lures in eastern US and western Mexico}, volume={33}, ISSN={["1573-1561"]}, DOI={10.1007/s10886-006-9233-6}, number={2}, journal={JOURNAL OF CHEMICAL ECOLOGY}, author={Groot, A. T. and Santangelo, R. G. and Ricci, E. and Brownie, C. and Gould, F. and Schal, Coby}, year={2007}, month={Feb}, pages={353–368} }
 @article{li_wu_gould_wang_miaoi_gao_guo_2007, title={Increasing tolerance to Cry1Ac cotton from cotton bollworm, Helicoverpa armigera, was confirmed in Bt cotton farming area of China}, volume={32}, ISSN={["1365-2311"]}, DOI={10.1111/j.1365-2311.2007.00891.x}, abstractNote={Abstract 1. Changes in the frequency of Cry1Ac resistance genes and shifts in tolerance of cotton bollworm, Helicoverpa armigera, to the Cry1Ac toxin were assessed using bioassays of F1 and F2 offspring of isofemale lines from Anci County of Hebei Province (a multiple-crop system including corn, soybean, peanut, and Bt cotton) and Xiajin County of Shandong Province (an intensive Bt cotton planting area) in Northern China during 2002–2005. 2. A conservative analysis of the overall results indicated that there was a small increase in the frequency of major, non-recessive resistance genes over time. 3. The relative average development ratings [RADR – growth rate of a line on a Bt diet in proportion to the growth rate on a non-Bt (NBT) diet] of the bollworm larvae in F1 tests increased significantly from year to year, indicating a gradual trend towards higher tolerance to Cry1Ac in the field populations. 4. There were also significant positive correlations between RADR of the lines in the F1 generation and the RADR of their F2 offspring, indicating that the tolerance was genetically based. 5. Quantitative genetic simulation analysis showed that resistance of H. armigera to Bt cotton in Xiajin could evolve to a high level in 11–15 years if no effective resistance management measures are carried out.}, number={4}, journal={ECOLOGICAL ENTOMOLOGY}, author={Li, Guo-Ping and Wu, Kong-Ming and Gould, Fred and Wang, Jian-Kang and Miaoi, Jin and Gao, Xi-Wu and Guo, Yu-Yuan}, year={2007}, month={Aug}, pages={366–375} }
 @article{huang_magori_lloyd_gould_2007, title={Introducing desirable transgenes into insect populations using Y-linked meiotic drive - A theoretical assessment}, volume={61}, ISSN={["1558-5646"]}, url={https://publons.com/publon/8533052/}, DOI={10.1111/j.1558-5646.2007.00075.x}, abstractNote={The use of genetic drive mechanisms to replace native mosquito genotypes with individuals bearing antipathogen transgenes is a potential strategy for repressing insect transmission of human diseases such as malaria and dengue. Antipathogen transgenes have been developed and tested, but efficient gene drive mechanisms are lacking. Here we theoretically assess the feasibility of introducing antipathogen genes into wild Aedes aegypti populations by using a naturally occurring meiotic drive system. We consider the release of males having both a Y-linked meiotic drive gene and an X-linked drive-insensitive response allele to which an antipathogen gene is linked. We use mathematical models and computer simulations to determine how the post-introduction dynamics of the antipathogen gene are affected by specific genetic characteristics of the system. The results show that when the natural population is uniformly sensitive to the meiotic drive gene, the antipathogen gene may be driven close to fixation if the fitness costs of the drive gene, the insensitive response allele, and the antipathogen gene are low. However, when the natural population has a small proportion of an X-linked insensitive response allele or an autosomal gene that strongly reduces the effect of the drive gene, the antipathogen gene does not spread if it has an associated fitness cost. Our modeling results provide a theoretical foundation for further experimental tests.}, number={4}, journal={EVOLUTION}, publisher={Blackwell Publishing Inc}, author={Huang, Yunxin and Magori, Krisztian and Lloyd, Alun L. and Gould, Fred}, year={2007}, month={Apr}, pages={717–726} }
 @article{huang_magori_lloyd_gould_2007, title={Introducing transgenes into insect populations using combined gene-drive strategies: Modeling and analysis}, volume={37}, ISSN={["0965-1748"]}, DOI={10.1016/j.ibmb.2007.06.002}, abstractNote={Engineered underdominance (EU), meiotic drive (MD) and Wolbachia have been proposed as mechanisms for driving anti-pathogen transgenes into natural populations of insect vectors of human diseases. EU can drive transgenes to high and stable frequencies but requires the release of sizeable numbers of engineered insects. MD and Wolbachia either cannot maintain high frequencies of transgenes or lack appropriate expression in critical tissues, but both can drive the transgenes to spread from very low initial frequencies. Here we use mathematical models to assess the utility of combining EU with MD or with Wolbachia. Under some conditions, the combination of EU and MD results in a more efficient transgene-drive strategy than either mechanism alone. This combined strategy could drive the transgenes to stable fixation and would require fewer released insects than EU alone, especially when only males are released. However, a combination of EU and Wolbachia does not work better than EU alone because it requires the release of even more engineered insects.}, number={10}, journal={INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY}, author={Huang, Yunxin and Magori, Krisztian and Lloyd, Alun L. and Gould, Fred}, year={2007}, month={Oct}, pages={1054–1063} }
 @article{heckel_gahan_baxter_zhao_shelton_gould_tabashnik_2007, title={The diversity of Bt resistance genes in species of Lepidoptera}, volume={95}, ISSN={["0022-2011"]}, DOI={10.1016/j.jip.2007.03.008}, abstractNote={Although the mode of action of Cry1A toxins produced by Bacillus thuringiensis is fairly well understood, knowledge of the molecular mechanisms by which lepidopteran species have evolved resistance to them is still in its infancy. The most common type of resistance has been called “Mode 1” and is characterized by recessive inheritance, >500-fold resistance to and reduced binding by at least one Cry1A toxin, and negligible cross-resistance to Cry1C. In three lepidopteran species, Heliothis virescens , Pectinophora gossypiella , and Helicoverpa armigera , Mode 1 resistance is caused by mutations in a toxin-binding 12-cadherin-domain protein expressed in the larval midgut. These mutations all interrupt the primary sequence of the protein and prevent its normal localization in the membrane, presumably removing a major toxic binding target of the Cry1A toxins. In Plutella xylostella , however, Mode 1 resistance appears to be caused by a different genetic mechanism, as Cry1A resistance is unlinked to the cadherin gene. Mapping studies in H. virescens have detected an additional major Cry1A resistance gene, which on the basis of comparative linkage mapping is distinct from the one in P. xylostella . An additional resistance mechanism supported by genetic data involves a protoxin-processing protease in Plodia interpunctella , and this is likely to be different from the genes mapped in Plutella and Heliothis . Thus, resistance to Cry1A toxins in species of Lepidoptera has a complex genetic basis, with at least four distinct, major resistance genes of which three are mapped in one or more species. The connection between resistance genes and the mechanisms they encode remains a challenging task to elucidate.}, number={3}, journal={JOURNAL OF INVERTEBRATE PATHOLOGY}, author={Heckel, David G. and Gahan, Linda J. and Baxter, Simon W. and Zhao, Jian-Zhou and Shelton, Anthony M. and Gould, Fred and Tabashnik, Bruce E.}, year={2007}, month={Jul}, pages={192–197} }
 @article{groot_horovitz_hamilton_santangelo_schal_gould_2006, title={Experimental evidence for interspecific directional selection on moth pheromone communication}, volume={103}, ISSN={["0027-8424"]}, DOI={10.1073/pnas.0508609103}, abstractNote={The chemical composition of the sexual communication signals of female moths is thought to be under strong stabilizing selection, because females that produce atypical pheromone blends suffer lower success in finding mates. This intraspecific selection pressure cannot explain the high diversity of moth pheromone blends found in nature. We conducted experiments to determine whether communication interference from males of closely related species could exert strong enough directional selection to cause evolution of these signals. Attraction and mating success of Heliothis subflexa (Hs) females with a normal quantitative trait locus for production of acetate pheromone components (norm-OAc) were compared with Hs females with an introgressed quantitative trait locus from Heliothis virescens (Hv) that dramatically decreased the amount of acetate esters in their pheromone glands (low-OAc). In field experiments with natural Hv and Hs populations, 10 times more Hv males were captured in traps baited with live low-OAc Hs females than in traps with norm-OAc Hs females. This pattern was confirmed in mate-choice assays in cages. Hybrids resulting from Hv-Hs matings have effectively zero fitness in the field. Combining our results with the extensive data set gathered in the past 40 years on the reproductive biology of Hv, we can quantitatively estimate that the directional selection exerted by Hv males on Hs females to produce relatively high amounts (>5%) of acetates can range from 0.135 to 0.231. Such intense interspecific selection may counteract intraspecific stabilizing selection that impedes evolutionary changes in pheromone blends and could lead to diversification of sexual signals.}, number={15}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Groot, AT and Horovitz, JL and Hamilton, J and Santangelo, RG and Schal, C and Gould, F}, year={2006}, month={Apr}, pages={5858–5863} }
 @misc{sinkins_gould_2006, title={Gene drive systems for insect disease vectors}, volume={7}, ISSN={["1471-0064"]}, DOI={10.1038/nrg1870}, number={6}, journal={NATURE REVIEWS GENETICS}, author={Sinkins, Steven P. and Gould, Fred}, year={2006}, month={Jun}, pages={427–435} }
 @article{gould_magori_huang_2006, title={Genetic strategies for controlling mosquito-borne diseases}, volume={94}, ISSN={["0003-0996"]}, DOI={10.1511/2006.3.238}, number={3}, journal={AMERICAN SCIENTIST}, author={Gould, F and Magori, K and Huang, YX}, year={2006}, pages={238–246} }
 @article{jackson_gould_bradley_van duyn_2006, title={Genetic variation for resistance to Bacillus thuringiensis toxins in Helicoverpa zea (Lepidoptera : Noctuidae) in eastern North Carolina}, volume={99}, DOI={10.1603/0022-0493-99.5.1790}, abstractNote={To evaluate resistance to Bacillus thuringiensis Berliner (Bt) toxins, adult female bollworms, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), were collected from four light trap locations in two eastern North Carolina counties from August to October during 2001 and 2002. Females were allowed to oviposit, and upon hatching, 24 neonates from each female (F1 lines) were screened for survival and growth rate on each of three diets: non-Bt diet, diet containing 5.0 microg/ml Cry1Ac toxin, or diet containing 5.0 microg/ml Cry2Ab toxin. These screens were designed to identify nonrecessive Bt resistance alleles present in field populations of bollworm. Of 561 and 691 families screened with both Cry1Ac- and Cry2Ab-containing diets in 2001 and 2002, respectively, no F1 lines were identified that seemed to carry a gene conferring substantial resistance to either Cry1Ac or Cry2Ab. Adults from F1 lines with growth scores in the highest (R) and lowest (S) quartiles were mated in four combinations, RxR, SxR, RxS, and SxS. Differences in growth rates of larvae from these crosses demonstrated that there is substantial quantitative genetic variation in eastern North Carolina populations for resistance to both Cry1Ac and Cry2Ab toxins. These findings, in addition to results suggesting partially dominant inheritance of resistance to Cry1Ac and Cry2Ab, are critically important for determining appropriate resistance management strategies that impact the sustainability of transgenic cotton, Gossypium hirsutum (L.).}, number={5}, journal={Journal of Economic Entomology}, author={Jackson, R. E. and Gould, F. and Bradley, J. R. and Van Duyn, J. W.}, year={2006}, pages={1790–1797} }
 @article{magori_gould_2006, title={Genetically engineered underdominance for manipulation of pest populations: A deterministic model}, volume={172}, ISSN={["0016-6731"]}, DOI={10.1534/genetics.105.051789}, abstractNote={Abstract We theoretically investigate the potential for introgressing a desired engineered gene into a pest population by linking the desired gene to DNA constructs that exhibit underdominance properties. Our deterministic model includes two independently segregating engineered constructs that both carry a lethal gene, but suppress each other. Only genotypes containing both or neither construct are viable. Both constructs also carry the desired gene with an independent regulatory mechanism. We examine the minimal number of individuals of an engineered strain that must be released into a natural population to successfully introgress the desired gene. We compare results for strains carrying single and multiple insertions of the constructs. When there are no fitness costs associated with the inserted constructs (when the lethal sequences are not expressed), the number of individuals that must be released decreases as the number of insertions in the genome of the released strain increases. As fitness costs increase, the number of individuals that must be released increases at a greater rate for release strains with more insertions. Under specific conditions this results in the strain with only a single insertion of each construct being the most efficient for introgressing the desired gene. We discuss practical implications of our findings.}, number={4}, journal={GENETICS}, author={Magori, K and Gould, F}, year={2006}, month={Apr}, pages={2613–2620} }
 @article{sheck_groot_ward_gemeno_wang_brownie_schal_gould_2006, title={Genetics of sex pheromone blend differences between Heliothis virescens and Heliothis subflexa: a chromosome mapping approach}, volume={19}, ISSN={["1420-9101"]}, DOI={10.1111/j.1420-9101.2005.00999.x}, abstractNote={Males of the noctuid moths, Heliothis virescens and H. subflexa locate mates based on species-specific responses to female-emitted pheromones that are composed of distinct blends of volatile compounds. We conducted genetic crosses between these two species and used AFLP marker-based mapping of backcross families (H. subflexa direction) to determine which of the 30 autosomes in these moths contained quantitative trait loci (QTL) controlling the proportion of specific chemical components in the pheromone blends. Presence/absence of single H. virescens chromosomes accounted for 7-34% of the phenotypic variation among backcross females in seven pheromone components. For a set of three similar 16-carbon acetates, two H. virescens chromosomes interacted in determining their relative amounts within the pheromone gland and together accounted for 53% of the phenotypic variance. Our results are discussed relative to theories about population genetic processes and biochemical mechanisms involved in the evolution of new sexual communication systems.}, number={2}, journal={JOURNAL OF EVOLUTIONARY BIOLOGY}, author={Sheck, AL and Groot, AT and Ward, CM and Gemeno, C and Wang, J and Brownie, C and Schal, C and Gould, F}, year={2006}, month={Mar}, pages={600–617} }
 @article{gould_cohen_bentur_kennedy_van duyn_2006, title={Impact of small fitness costs on pest adaptation to crop varieties with multiple toxins: A heuristic model}, volume={99}, DOI={10.1603/0022-0493-99.6.2091}, abstractNote={A deterministic two-locus model was used to examine how small fitness costs to individuals carrying resistance alleles could impact the risk of panmictic insect pest populations adapting to crop varieties that produced two distinct toxins. Parameters examined were (1) level of toxicity of each toxin, (2) initial frequencies of alleles for adaptation to the toxins, (3) percentage of population feeding on nontoxic plants, and (4) level of fitness cost associated with adaptation to each of the two toxins. Resistance to each toxin was assumed to be biochemically independent, controlled by a resistance coding allele at a single locus, and inherited as a partially recessive trait in the field. When plants are extremely toxic to the pest, effective refuge size is 10%, and there is a fitness cost to resistance alleles only when in homozygous form (5%), the pest population is never predicted to adapt to either toxin as long as the initial frequencies of the resistance alleles are below 0.05. Even if the initial frequency of the allele for adapting to one toxin is 0.95 when a two-toxin cultivar completely replaces a one-toxin cultivar, the model predicts that a low equilibrium allelic frequency will develop for both resistance alleles, as long as the frequency of the allele for adapting to the second toxin is initially 0.001 or less. If cultivars with one and two toxins are planted, the model predicts that resistance will develop. Nonrandom mating and stochastic variation within subpopulations also could lead to evolution of resistance.}, number={6}, journal={Journal of Economic Entomology}, author={Gould, F. and Cohen, M. B. and Bentur, J. S. and Kennedy, G. G. and Van Duyn, J.}, year={2006}, pages={2091–2099} }
 @article{groot_fan_brownie_jurenka_gould_schal_2005, title={Effect of PBAN on pheromone production by mated Heliothis virescens and Heliothis subflexa females}, volume={31}, ISSN={["1573-1561"]}, DOI={10.1007/s10886-005-0970-8}, number={1}, journal={JOURNAL OF CHEMICAL ECOLOGY}, author={Groot, AT and Fan, YL and Brownie, C and Jurenka, RA and Gould, F and Schal, C}, year={2005}, month={Jan}, pages={14–28} }
 @article{gahan_ma_coble_gould_moar_heckel_2005, title={Genetic basis of resistance to Cry1Ac and Cry2Aa in Heliothis virescens (Lepidoptera : Noctuidae)}, volume={98}, ISSN={["1938-291X"]}, DOI={10.1603/0022-0493-98.4.1357}, abstractNote={The development of pest resistance to transgenic crop plants producing insecticidal toxins from Bacillus thuringiensis Berliner (Bt) poses a major threat to their sustainable use in agriculture. “Pyramiding” two toxins with different modes of actions in the same plant is now being used to delay the evolution of resistance in the insects, but this strategy could fail if a single gene in a pest confers resistance to both toxins. The CP73 strain of the cotton pest Heliothis virescens (F.) is resistant to both Cry1Ac and Cry2Aa toxins from Bt. We explored the genetic basis of resistance in this strain with a backcross, split-family design. The gene with the largest effect on Cry1Ac resistance in CP73 (BtR-5) maps to linkage group 10 of H. virescens and thus differs from the previously described linkage group 9 BtR-4 resistance found in the YHD2 strain, involving mutation of the gene encoding a 12-domain cadherin-like binding target of the Cry1A toxins. Neither BtR-4 nor BtR-5 seems to confer significant resistance to Cry2Aa. A majority of the linkage groups studied in one backcross family made a small positive contribution to resistance for both toxins. Thus, the Cry2Aa resistance in CP73 is not caused by either of the two major Cry1Ac resistance-conferring genes but instead probably has a quantitative genetic basis.}, number={4}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Gahan, LJ and Ma, YT and Coble, MLM and Gould, F and Moar, WJ and Heckel, DG}, year={2005}, month={Aug}, pages={1357–1368} }
 @article{groot_gemeno_brownie_gould_schal_2005, title={Male and female antennal responses in Heliothis virescens and H subflexa to conspecific and heterospecific sex pheromone compounds}, volume={34}, ISSN={["1938-2936"]}, DOI={10.1603/0046-225X-34.2.256}, abstractNote={To determine whether Heliothis virescens and H. subflexa, two closely related sympa- trically occurring species, differ in their antennal responses to conspeciÞc and heterospeciÞc pher- omone compounds, we recorded electroantennogram (EAG) responses of male and female antennae of both species to eight different compounds loaded on Þlter paper dispensers. If antennal responses were found to differ in the two species, EAG-recordings from F1 hybrids and backcrosses between these species could be used in developing an understanding of the genetic architecture of variation in olfactory signal perception. However, all compounds elicited EAG responses in all male antennae tested, and no quantitative differences in response were found between the two species, except for the response to 1 mg (Z)-11-hexadecenol (Z11Ð16:OH), which elicited larger EAG responses in H. subflexa than in H. virescens males. This difference is consistent with the idea that this pheromone component is less important in the biology of H. virescens. Female antennae of both species were less responsive to the major sex pheromone compound, (Z)-11-hexadecenal (Z11Ð16:Ald), than male antennae; 10 g Z11Ð16:Ald, which elicited strong EAG responses in males, produced female EAGs similar to control puffs of air. However, higher doses of Z11Ð16:Ald elicited signiÞcant EAG responses in female antennae of both species. Female antennae of both species also responded to most other pheromone compounds, except Z11Ð16:OH. These results support the hypothesis that autodetection of sex pheromones occurs in females of bothH.virescens andH.subflexa. Whether females behaviorally respond to any, or to combinations, of these compounds remains to be elucidated.}, number={2}, journal={ENVIRONMENTAL ENTOMOLOGY}, author={Groot, A and Gemeno, C and Brownie, C and Gould, F and Schal, C}, year={2005}, month={Apr}, pages={256–263} }
 @article{schliekelman_ellner_gould_2005, title={Pest control by genetic manipulation of sex ratio}, volume={98}, DOI={10.1093/jee/98.1.18}, abstractNote={We model the release of insects carrying an allele at multiple loci that shifts sex ratios in favor of males. We model two approaches to sex ratio alteration. In the first (denoted SD), meiotic segregation (or sperm fertility) is distorted in favor of gametes carrying the male-determining genetic element (e.g., Y-chromosome). It is assumed that any male carrying at least one copy of the SD allele produces only genotypically male offspring. In the second approach (denoted PM), the inserted allele alters sex ratio by causing genetically female individuals to become phenotypically male. It is assumed that any insect carrying at least one copy of the PM allele is phenotypically male. Both approaches reduce future population growth by reducing the number of phenotypic females. The models allow variation in the number of loci used in the release, the size of the release, and the negative fitness effect caused by insertion of each sex ratio altering allele. We show that such releases may be at least 2 orders of magnitude more effective than sterile male releases (SIT) in terms of numbers of surviving insects. For example, a single SD release with two released insects for every wild insect and a 5% fitness cost per inserted allele could reduce the target population to 1/1000th of the no-release population size, whereas a similar-sized SIT release would only reduce the population to one-fifth of its original size. We also compare these two sex ratio alteration approaches to a female-killing (FK) system and the sterile male technique when there are repeated releases over a number of generations. In these comparisons, the SD approach is the most efficient with equivalent pest suppression achieved by release of approximately 1 SD, 1.5-20 PM, 2-70 FK, and 16-3,000 SIT insects, depending on conditions. We also calculate the optimal number of SD and PM allele insertions to be used under various conditions, assuming that there is an additional genetic load incurred for each allelic insertion.}, number={1}, journal={Journal of Economic Entomology}, author={Schliekelman, P. and Ellner, S. and Gould, F.}, year={2005}, pages={18–34} }
 @article{mallampalli_gould_barbosa_2005, title={Predation of Colorado potato beetle eggs by a polyphagous ladybeetle in the presence of alternate prey: potential impact on resistance evolution}, volume={114}, ISSN={["0013-8703"]}, DOI={10.1111/j.0013-8703.2005.00232.x}, abstractNote={The influence of prey choice on the predation of a target prey item by a polyphagous insect predator was investigated in field plot studies. The target prey consisted of eggs of the Colorado potato beetle (CPB), Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae), and the predator was the 12-spotted ladybeetle, Coleomegilla maculata Lengi (Coleoptera: Coccinellidae). Eggs of the European corn borer (ECB), Ostrinia nubilalis Hubner (Lepidoptera: Pyralidae), and nymphs and adults of the green peach aphid, Myzus persicae Sulzer (Homoptera: Aphididae), comprised the alternative prey choices. The objectives of these studies were to: (1) examine predation in a multiprey scenario likely to occur in an agroecosystem, and (2) use the data to simulate the impact of predator-induced mortality on the evolution of resistance to Bt-transgenic plants in the target herbivore. Simulations of the rate of resistance evolution were carried out using a deterministic genetic model. Experiments were performed using potato field plots planted in a manner reflecting a 25% or 50% non-transgenic refuge. CPB eggs were infested so as to mimic the densities of resistant and susceptible populations that might occur in commercial Bt-transgenic plantings. Densities of predators and alternate prey species were chosen to represent those that might typically occur in potato crops in the eastern USA. Simulation results indicated that when ECB eggs were present, predation on CPB eggs either became inversely spatially density-dependent, or increased significantly in a density-dependent manner. When aphids were present, predation became positively density-dependent. Model simulations predicted that ECB egg presence is beneficial, in that resistance was delayed by up to 40 pest generations (as compared to the scenario with CPB as the only prey), while aphid presence accelerated resistance evolution by 18 generations. Results suggest that resistance management strategies should take into account the composition of prey species available to generalist predators typically present, so as to best delay pest adaptation to Bt-toxins.}, number={1}, journal={ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA}, author={Mallampalli, N and Gould, F and Barbosa, P}, year={2005}, month={Jan}, pages={47–54} }
 @article{rasgon_gould_2005, title={Transposable element insertion location bias and the dynamics of gene drive in mosquito populations}, volume={14}, ISSN={["0962-1075"]}, DOI={10.1111/j.1365-2583.2005.00580.x}, abstractNote={Some vector-borne disease control strategies using transgenic mosquitoes require transgene spread to high frequency in populations. Transposable elements (TEs) are DNA sequences that replicate and transpose within the genomes of other organisms and may therefore be represented in the next generation in higher frequencies than predicted by Mendelian segregation. This over-representation has allowed some TEs to spread through natural populations. Transgenes incorporated within a TE sequence are expected to be driven into populations as long as there is a positive balance between fitness costs and over-representation. Models have been used to examine parameters that affect this balance but did not take into account biased insertion of TEs to linked sites in the genome. A simulation model was created to examine the impact of insertion bias on TE spread in mosquito populations. TEs that induce no fitness costs are predicted to increase in frequency over a wide range of parameter values but spread is slower for lower levels of transposition and non-local movement. If TEs are costly, high proportions of local movement can slow or halt spread. To function as a robust transgene drive mechanism a TE should replicate and transpose > 10%/insert/generation, induce < 1% fitness cost/insert, and move preferentially to unlinked sites in the genome.}, number={5}, journal={INSECT MOLECULAR BIOLOGY}, author={Rasgon, JL and Gould, F}, year={2005}, month={Oct}, pages={493–500} }
 @article{jackson_bradley_van duyn_gould_2004, title={Comparative production of Helicoverpa zea (Lepidoptera : Noctuidae) from transgenic cotton expressing either one or two Bacillus thuringiensis proteins with and without insecticide oversprays}, volume={97}, ISSN={["1938-291X"]}, DOI={10.1603/0022-0493-97.5.1719}, abstractNote={Transgenic cotton, Gossypium hirsutum (L.), expressing either one or two Bacillus thuringiensis ssp. kurstaki Berliner (Bt) proteins was compared with the conventional sister line in field experiments with regard to production of bollworm, Helicoverpa zea (Boddie), and bolls damaged by bollworm. The relative numbers of bollworms that developed on Bollgard (Monsanto Co., St. Louis, MO), Bollgard II (Monsanto Co.), and conventional cotton were estimated under nontreated conditions in 2000 and both insecticide-treated and nontreated conditions in 2001–2002 in North Carolina tests. Averaged across seven field studies under nontreated conditions, Bollgard cotton generated statistically similar numbers of large (L4–L5) bollworm larvae compared with the conventional variety; however, Bollgard cotton produced significantly fewer damaged bolls and bollworm adults than the conventional variety. Production of large larvae, damaged bolls, and adults was decreased dramatically by Bollgard II cotton as compared with Bollgard and conventional varieties. When comparing insecticide-treated and nontreated cotton genotypes, both Bt cotton sustained less boll damage than the conventional variety averaged across insecticide regimes; furthermore, Bollgard II cotton had fewer damaged bolls than the Bollgard variety. When averaged across cotton genotypes, pyrethroid oversprays reduced the numbers of damaged bolls compared with the nontreated cotton. Insecticide-treated Bollgard cotton, along with insecticide-treated and nontreated Bollgard II cotton reduced production of bollworm larvae, pupae, and adults. However, the addition of pyrethroid oversprays to Bollgard II cotton seemed to be the best resistance management strategy available for bollworm because no bollworms were capable of completing development under these conditions.}, number={5}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Jackson, RE and Bradley, JR and Van Duyn, JW and Gould, F}, year={2004}, month={Oct}, pages={1719–1725} }
 @article{tabashnik_gould_carriere_2004, title={Delaying evolution of insect resistance to transgenic crops by decreasing dominance and heritability}, volume={17}, ISSN={["1420-9101"]}, DOI={10.1111/j.1420-9101.2004.00695.x}, abstractNote={The refuge strategy is used widely for delaying evolution of insect resistance to transgenic crops that produce Bacillus thuringiensis (Bt) toxins. Farmers grow refuges of host plants that do not produce Bt toxins to promote survival of susceptible pests. Many modelling studies predict that refuges will delay resistance longest if alleles conferring resistance are rare, most resistant adults mate with susceptible adults, and Bt plants have sufficiently high toxin concentration to kill heterozygous progeny from such matings. In contrast, based on their model of the cotton pest Heliothis virescens, Vacher et al. (Journal of Evolutionary Biology, 16, 2003, 378) concluded that low rather than high toxin doses would delay resistance most effectively. We demonstrate here that their conclusion arises from invalid assumptions about larval concentration-mortality responses and dominance of resistance. Incorporation of bioassay data from H. virescens and another key cotton pest (Pectinophora gossypiella) into a population genetic model shows that toxin concentrations high enough to kill all or nearly all heterozygotes should delay resistance longer than lower concentrations.}, number={4}, journal={JOURNAL OF EVOLUTIONARY BIOLOGY}, author={Tabashnik, BE and Gould, F and Carriere, Y}, year={2004}, month={Jul}, pages={904–912} }
 @article{li_wu_gould_feng_he_guo_2004, title={Frequency of Bt resistance genes in Helicoverpa armigera populations from the Yellow River cotton-farming region of China}, volume={112}, ISSN={["1570-7458"]}, DOI={10.1111/j.0013-8703.2004.00191.x}, abstractNote={Bt cotton has been widely planted in the Yellow River valley of China since 1998. Anci County in Hebei Province and Xiajin County in Shandong Province are two areas where almost 100% of the cotton grown produces Cry1A(c) toxin. These areas were therefore selected for analysis of the frequency of genes coding for resistance to Cry1A(c) in field populations of the bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae). In 2002, adult females were collected using light traps. Females were caged individually and were allowed to lay eggs. At hatch, 25–35 larvae from each female were screened for growth rate on normal artificial diet, and on diet containing 1.0 µg of Cry1A(c) toxin per ml of diet. This growth rate bioassay was designed to detect non-recessive resistance genes in heterozygous genotypes and to detect recessive resistance genes only when present in a homozygous resistant genotype. The bioassay detected one resistant individual out of 234 screened in Anci and one resistant individual out of 420 in Xiajin. These results suggest that a conservative estimate of the resistance gene frequency is 0.00107 in the Anci population, and 0.00059 in the Xiajin population. Our results indicate that minor resistance genes or less dominant genes for resistance may occur at higher frequencies, especially in the Xiajin population.}, number={2}, journal={ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA}, author={Li, GP and Wu, KM and Gould, F and Feng, HQ and He, YZ and Guo, YY}, year={2004}, month={Aug}, pages={135–143} }
 @article{groot_ward_wang_pokrzywa_o’brien_bennett_kelly_santangelo_schal_gould_2004, title={Introgressing pheromone QTL between species: Towards an evolutionary understanding of differentiation in sexual communication}, volume={30}, ISSN={["1573-1561"]}, DOI={10.1007/s10886-004-7946-y}, number={12}, journal={Journal of Chemical Ecology}, author={Groot, A.T. and Ward, C. and Wang, J. and Pokrzywa, A. and O’Brien, J. and Bennett, J. and Kelly, J. and Santangelo, R.G. and Schal, C. and Gould, F.}, year={2004}, pages={2495–2514} }
 @misc{gould_schliekelman_2004, title={Population genetics of autocidal control and strain replacement}, volume={49}, ISSN={["1545-4487"]}, DOI={10.1146/annurev.ento.49.061802.123344}, abstractNote={The concept that an insect species' genome could be altered in a manner that would result in the control of that species (i.e., autocidal control) or in the replacement of a pestiferous strain of the species with a more benign genotype was first proposed in the mid-twentieth century. A major research effort in population genetics and ecology followed and led to the development of a set of classical genetic control approaches that included use of sterile males, conditional lethal genes, translocations, compound chromosomes, and microbe-mediated infertility. Although there have been a number of major successes in application of classical genetic control, research in this area has declined in the past 20 years for technical and societal reasons. Recent advances in molecular biology and transgenesis research have renewed interest in genetically based control methods because these advances may remove some major technical problems that have constrained effective genetic manipulation of pest species. Population genetic analyses suggest that transgenic manipulations may enable development of strains that would be 10 to over 100 times more efficient than strains developed by classical methods. Some of the proposed molecular approaches to genetic control involve modifications of classical approaches such as conditional lethality, whereas others are novel. Experience from the classical era of genetic control research indicates that the population structure and population dynamics of the target population will determine which, if any, genetic control approaches would be appropriate for addressing a specific problem. As such, there continues to be a need for ongoing communication between scientists who are developing strains and those who study the native pest populations.}, journal={ANNUAL REVIEW OF ENTOMOLOGY}, author={Gould, F and Schliekelman, P}, year={2004}, pages={193–217} }
 @article{jurat-fuentes_gahan_gould_heckel_adang_2004, title={The HevCaLP protein mediates binding specificity of the Cry1A class of Bacillus thuringiensis toxins in Heliothis virescens}, volume={43}, ISSN={["0006-2960"]}, DOI={10.1021/bi048500i}, abstractNote={Retrotransposon-mediated disruption of the BtR-4 gene encoding the Heliothis virescens cadherin-like protein (HevCaLP) is linked to high levels of resistance in the YHD2 strain to Cry1Ac toxin from Bacillus thuringiensis. This suggests that HevCaLP functions as a Cry1Ac toxin receptor on the surface of midgut cells in susceptible larvae and that the BtR-4 gene disruption eliminates this protein in resistant larvae. However, Cry1Ac toxin binding to HevCaLP is yet to be reported. We used the polymerase chain reaction and immunoblotting as tools to discriminate between individual H. virescens larval midguts from susceptible (YDK) and resistant (CXC, KCBhyb, and YHD2-B) strains according to their BtR-4 gene disruption genotype and phenotype. This approach allowed us to test the correlation between BtR-4 gene disruption, lack of HevCaLP, and altered Cry1A toxin binding. Toxin-binding assays using brush border membrane vesicles revealed that a wild-type BtR-4 allele is necessary for HevCaLP production and Cry1Aa toxin binding, while most of Cry1Ab and Cry1Ac binding was independent of the BtR-4 genotype. Moreover, toxin competition experiments show that KCBhyb midguts lacking HevCaLP are more similar to midguts of the original YHD2 strain than to the current YHD2-B strain. This resolves discrepancies in published studies of Cry1A binding in YHD2 and supports our earlier suggestion that a separate genetic change occurred in YHD2 after appearance of the cadherin disruption, conferring even higher resistance in the resulting YHD2-B strain as well as a large reduction in Cry1Ab and Cry1Ac binding.}, number={44}, journal={BIOCHEMISTRY}, author={Jurat-Fuentes, JL and Gahan, LJ and Gould, FL and Heckel, DG and Adang, MJ}, year={2004}, month={Nov}, pages={14299–14305} }
 @article{gould_2003, title={Bt-resistance management - theory meets data}, volume={21}, ISSN={["1087-0156"]}, DOI={10.1038/nbt1203-1450}, number={12}, journal={NATURE BIOTECHNOLOGY}, author={Gould, F}, year={2003}, month={Dec}, pages={1450–1451} }
 @article{jurat-fuentes_gould_adang_2003, title={Dual resistance to Bacillus thuringiensis Cry1Ac and Cry2Aa toxins in Heliothis virescens suggests multiple mechanisms of resistance}, volume={69}, ISSN={["1098-5336"]}, DOI={10.1128/AEM.69.10.5898-5906.2003}, abstractNote={ABSTRACT One strategy for delaying evolution of resistance to Bacillus thuringiensis crystal (Cry) endotoxins is the production of multiple Cry toxins in each transgenic plant (gene stacking). This strategy relies upon the assumption that simultaneous evolution of resistance to toxins that have different modes of action will be difficult for insect pests. In B. thuringiensis- transgenic (Bt) cotton, production of both Cry1Ac and Cry2Ab has been proposed to delay resistance of Heliothis virescens (tobacco budworm). After previous laboratory selection with Cry1Ac, H. virescens strains CXC and KCBhyb developed high levels of cross-resistance not only to toxins similar to Cry1Ac but also to Cry2Aa. We studied the role of toxin binding alteration in resistance and cross-resistance with the CXC and KCBhyb strains. In toxin binding experiments, Cry1A and Cry2Aa toxins bound to brush border membrane vesicles from CXC, but binding of Cry1Aa was reduced for the KCBhyb strain compared to susceptible insects. Since Cry1Aa and Cry2Aa do not share binding proteins in H. virescens , our results suggest occurrence of at least two mechanisms of resistance in KCBhyb insects, one of them related to reduction of Cry1Aa toxin binding. Cry1Ac bound irreversibly to brush border membrane vesicles (BBMV) from YDK, CXC, and KCBhyb larvae, suggesting that Cry1Ac insertion was unaffected. These results highlight the genetic potential of H. virescens to become resistant to distinct Cry toxins simultaneously and may question the effectiveness of gene stacking in delaying evolution of resistance.}, number={10}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Jurat-Fuentes, JL and Gould, FL and Adang, MJ}, year={2003}, month={Oct}, pages={5898–5906} }
 @article{burd_gould_bradley_van duyn_moar_2003, title={Estimated frequency of nonrecessive Bt resistance genes in bollworm, Helicoverpa zea (Boddie) (Lepidoptera : Noctuidae) in eastern North Carolina}, volume={96}, ISSN={["0022-0493"]}, DOI={10.1603/0022-0493-96.1.137}, number={1}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Burd, AD and Gould, F and Bradley, JR and Van Duyn, JW and Moar, WJ}, year={2003}, month={Feb}, pages={137–142} }
 @misc{roe_bailey_gould_kennedy_sutula_2003, title={Insecticide resistance assay}, volume={6,517,856}, number={2003 Feb. 11}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Roe, R. M. and Bailey, W. D. and Gould, F. and Kennedy, G. G. and Sutula, C. L.}, year={2003} }
 @article{storer_peck_gould_van duyn_kennedy_2003, title={Sensitivity analysis of a spatially-explicit stochastic simulation model of the evolution of resistance in Helicoverpa zea (Lepidoptera : Noctuidae) to Bt transgenic corn and cotton}, volume={96}, ISSN={["0022-0493"]}, DOI={10.1603/0022-0493-96.1.173}, number={1}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Storer, NP and Peck, SL and Gould, F and Van Duyn, JW and Kennedy, GG}, year={2003}, month={Feb}, pages={173–187} }
 @article{storer_peck_gould_van duyn_kennedy_2003, title={Spatial processes in the evolution of resistance in Helicoverpa zea (Lepidoptera : Noctuidae) to Bt transgenic corn and cotton in a mixed agroecosystem: a biology-rich stochastic simulation model}, volume={96}, ISSN={["1938-291X"]}, DOI={10.1603/0022-0493-96.1.156}, number={1}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Storer, NP and Peck, SL and Gould, F and Van Duyn, JW and Kennedy, GG}, year={2003}, month={Feb}, pages={156–172} }
 @article{jurat-fuentes_gould_adang_2002, title={Altered glycosylation of 63- and 68-kilodalton microvillar proteins in Heliothis virescens correlates with reduced Cry1 toxin binding, decreased pore formation, and increased resistance to Bacillus thuringiensis Cry1 toxins}, volume={68}, ISSN={["1098-5336"]}, DOI={10.1128/AEM.68.11.5711-5717.2002}, abstractNote={ABSTRACT The binding and pore formation abilities of Cry1A and Cry1Fa Bacillus thuringiensis toxins were analyzed by using brush border membrane vesicles (BBMV) prepared from sensitive (YDK) and resistant (YHD2) strains of Heliothis virescens . 125 I-labeled Cry1Aa, Cry1Ab, and Cry1Ac toxins did not bind to BBMV from the resistant YHD2 strain, while specific binding to sensitive YDK vesicles was observed. Binding assays revealed a reduction in Cry1Fa binding to BBMV from resistant larvae compared to Cry1Fa binding to BBMV from sensitive larvae. In agreement with this reduction in binding, neither Cry1A nor Cry1Fa toxin altered the permeability of membrane vesicles from resistant larvae, as measured by a light-scattering assay. Ligand blotting experiments performed with BBMV and 125 I-Cry1Ac did not differentiate sensitive larvae from resistant larvae. Iodination of BBMV surface proteins suggested that putative toxin-binding proteins were exposed on the surface of the BBMV from resistant insects. BBMV protein blots probed with the N -acetylgalactosamine-specific lectin soybean agglutinin (SBA) revealed altered glycosylation of 63- and 68-kDa glycoproteins but not altered glycosylation of known Cry1 toxin-binding proteins in YHD2 BBMV. The F1 progeny of crosses between sensitive and resistant insects were similar to the sensitive strain when they were tested by toxin-binding assays, light-scattering assays, and lectin blotting with SBA. These results are evidence that a dramatic reduction in toxin binding is responsible for the increased resistance and cross-resistance to Cry1 toxins observed in the YHD2 strain of H. virescens and that this trait correlates with altered glycosylation of specific brush border membrane glycoproteins.}, number={11}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Jurat-Fuentes, JL and Gould, FL and Adang, MJ}, year={2002}, month={Nov}, pages={5711–5717} }
 @article{gould_blair_reid_rennie_lopez_micinski_2002, title={Bacillus thuringiensis-toxin resistance management: Stable isotope assessment of alternate host use by Helicoverpa zea}, volume={99}, ISSN={["0027-8424"]}, DOI={10.1073/pnas.242382499}, abstractNote={Data have been lacking on the proportion of Helicovera zea larvae that develop on noncotton host plants that can serve as a refuge from selection pressure for adaptation to transgenic cotton varieties that produce a toxin from the bacterium Bacillus thuringiensis. We found that individual H. zea moths that develop as larvae on cotton and other plants with C3 physiology have a different ratio of 13C to 12C than moths that develop on plants with C4 physiology, such as corn. We used this finding in determining the minimum percentage of moths that developed on noncotton hosts in two cotton-growing areas. Our results indicate that local corn can serve as a refuge for H. zea in midsummer. Our results contrast dramatically with the prevailing hypothesis that the large majority of late-season moths are produced from larvae feeding on cotton, soybean, and other C3 plants. Typically, <50% of moths captured in August through October have isotope ratios indicative of larval feeding on C3 plants. In one October sample, 100% of the moths originated from C4 hosts even though C4 crops were harvested at least 1 mo earlier, and no common wild C4 hosts were available. These findings support other research indicating that many late-season H. zea moths captured in Louisiana and Texas are migrants whose larvae developed on corn in more northern locations. Our isotope data on moths collected in Texas early in the season indicate that the majority of overwintering H. zea do not originate from cotton-feeding larvae and may be migrants from Mexico. Non-Bt corn in Mexico and the U.S. corn belt appears to serve as an important refuge for H. zea.}, number={26}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Gould, F and Blair, N and Reid, M and Rennie, TL and Lopez, J and Micinski, S}, year={2002}, month={Dec}, pages={16581–16586} }
 @article{oppenheim_gould_2002, title={Behavioral adaptations increase the value of enemy-free space for Heliothis subflexa, a specialist herbivore.}, volume={56}, DOI={10.1111/j.0014-3820.2002.tb01379.x}, abstractNote={We investigated the importance of specialized behaviors in the use of enemy-free space by comparing the host-use behavior of two closely related moths, Heliothis subflexa Guenee and H. virescens Fabricius. Heliothis subflexa is a specialist on plants in the genus Physalis, whereas H. virescens is an extreme generalist, feeding on plants in at least 14 families. Heliothis subflexa uses the inflated calyx surrounding Physalis fruits as enemy-free space, and field rates of parasitism for H. subflexa on Physalis are much lower than for H. virescens on tobacco and cotton, common hosts found in the same habitat as Physalis. If Physalis, architecture were solely responsible for H. subflexa's low rates of parasitism on Physalis, we predicted that H. virescens larvae experimentally induced to feed on Physalis would experience parasitism rates similar to those of H. subflexa. We found, however, that specialized host-use and host-acceptance behaviors are integral to the use of enemy-free space on Physalis and strongly augment the effects of the structural refuge. In laboratory assays, we found considerable differences between the larval behavior of the specialist. H. subflexa, and the generalist, H. virescens, and these contributed to H. subflexa's superior use of enemy-free space on Physalis. We tested the importance of these behavioral differences in the field by comparing parasitism of H. virescens on Physalis, H. virescens on tobacco, and H. subflexa on Physalis by Cardiochiles nigriceps Vierick, a specialist braconid parasitoid. For H. virescens, a threefold decrease in parasitism occurred when feeding on Physalis (mean parasitism +/- SEM = 13 +/- 4%) rather than tobacco (43 +/- 4%), a difference we attribute to the structural refuge provided by Physalis. However, parasitism of H. virescens on Physalis was more than ten times as great as that of H. subflexa on Pliv.salis (1 +/- 4%), supporting the hypothesis that specialized behaviors have a substantial impact on use of Physalis as enemy-free space. Behavioral adaptations may be central to the use of enemy-free space by phytophagous insects and may act as an important selective force in the evolution of dietary specialization.}, number={4}, journal={Evolution}, author={Oppenheim, S. J. and Gould, F.}, year={2002}, pages={679–689} }
 @article{oppenheim_gould_2002, title={Is attraction fatal? The effects of herbivore-induced plant volatiles on herbivore parasitism}, volume={83}, ISSN={["1939-9170"]}, DOI={10.2307/3072090}, number={12}, journal={ECOLOGY}, author={Oppenheim, SJ and Gould, F}, year={2002}, month={Dec}, pages={3416–3425} }
 @article{lu_kennedy_gould_2001, title={Genetic analysis of larval survival and larval growth of two populations of Leptinotarsa decemlineata on tomato}, volume={99}, ISSN={["1570-7458"]}, DOI={10.1046/j.1570-7458.2001.00812.x}, abstractNote={The genetics of adaptation to tomato in Leptinotarsa decemlineata (Say) were investigated in reciprocal F 1 , F 2 , and backcross populations generated from crosses between beetles from a tomato adapted population and from a population that was poorly adapted to tomato. Larvae from the parent and test populations were reared on tomato for four days, after which survivorship and larval weights were recorded. Most results indicate that differences in larval growth and survival on tomato between the parent populations are largely determined by autosomal, polygenic mechanisms, the inheritance of which involves a significant dominance component. However, results from F 2 crosses are not consistent with this conclusion. A significant difference in larval weights, but not in survival, between reciprocal F 1 populations in an analysis of combined data from four separate experiments suggests that maternal cytoplasmic effects may contribute to differences in larval performance on tomato between the adapted and unadapted populations. The unusual results obtained from F 2 crosses in this study are not atypical of results from previous studies of the genetics of adaptation to host plants by the Colorado potato beetle. Host plant adaptation by Colorado potato beetles may therefore involve unusual genetic mechanisms that are not easily assessed by classical Mendelian analysis.}, number={2}, journal={ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA}, author={Lu, WH and Kennedy, GG and Gould, F}, year={2001}, month={May}, pages={143–155} }
 @article{gahan_gould_heckel_2001, title={Identification of a gene associated with bit resistance in Heliothis virescens}, volume={293}, ISSN={["0036-8075"]}, DOI={10.1126/science.1060949}, abstractNote={Transgenic crops producing insecticidal toxins from Bacillus thuringiensis (Bt) are widely used for pest control. Bt-resistant insect strains have been studied, but the molecular basis of resistance has remained elusive. Here, we show that disruption of a cadherin-superfamily gene by retrotransposon-mediated insertion was linked to high levels of resistance to the Bt toxin Cry1Ac in the cotton pest Heliothis virescens. Monitoring the early phases of Bt resistance evolution in the field has been viewed as crucial but extremely difficult, especially when resistance is recessive. Our findings enable efficient DNA-based screening for resistant heterozygotes by directly detecting the recessive allele.}, number={5531}, journal={SCIENCE}, author={Gahan, LJ and Gould, F and Heckel, DG}, year={2001}, month={Aug}, pages={857–860} }
 @article{bailey_brownie_bacheler_gould_kennedy_sorenson_roe_2001, title={Species diagnosis and Bacillus thuringiensis resistance monitoring of Heliothis virescens and Helicoverpa zea (Lepidoptera : noctuidae) field strains from the southern United States using feeding disruption bioassays}, volume={94}, ISSN={["1938-291X"]}, DOI={10.1603/0022-0493-94.1.76}, abstractNote={Validation of a feeding disruption bioassay for the detection of resistance to Bacillus thuringiensis toxin and species identification is reported using field strains of Heliothis virescens and Helicoverpa zea collected from the southern United States in 1998. Feeding disruption is measured by a lack of fecal production from larvae exposed to a diagnostic concentration of CryIAc in a blue indicator diet. The bioassay provided rapid (24 h) diagnosis of the species composition of larvae tested and also monitored for the presence of resistance in H. virescens. An additional diagnostic concentration was established for monitoring resistance in H. zea. A probit model was used to compare the fecal production responses of insect strains over a range of CryIAc doses. Probability calculations, derived from our assay results, are also presented to aid in the interpretation of future results from field trials. Integration of the feeding disruption bioassay into integrated pest management programs is discussed.}, number={1}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Bailey, WD and Brownie, C and Bacheler, JS and Gould, F and Kennedy, GG and Sorenson, CE and Roe, RM}, year={2001}, month={Feb}, pages={76–85} }
 @article{karim_gould_dean_2000, title={Bacillus thuringiensis delta-endotoxin proteins show a correlation in toxicity and short circuit current inhibition against Helicoverpa zea}, volume={41}, ISSN={["1432-0991"]}, DOI={10.1007/s002840010122}, number={3}, journal={CURRENT MICROBIOLOGY}, author={Karim, S and Gould, F and Dean, DH}, year={2000}, month={Sep}, pages={214–219} }
 @article{roe_bailey_gould_sorenson_kennedy_bacheler_rose_hodgson_sutula_2000, title={Detection of resistant insects and IPM}, ISBN={0890542465}, journal={Emerging technologies for integrated pest management : concepts, research, and implementation}, publisher={St. Paul, MN : APS Press,}, author={Roe, R. M. and Bailey, W. D. and Gould, F. and Sorenson, C. E. and Kennedy, G. G. and Bacheler, J. S. and Rose, R. L. and Hodgson, E. and Sutula, C. L.}, year={2000}, pages={67} }
 @article{karim_riazuddin_gould_dean_2000, title={Determination of receptor binding properties of Bacillus thuringiensis delta-endotoxins to cotton bollworm (Helicoverpa zea) and pink bollworm (Pectinophora gossypiella) midgut brush border membrane vesicles}, volume={67}, ISSN={["1095-9939"]}, DOI={10.1006/pest.2000.2491}, abstractNote={Abstract Pesticidal activity and receptor binding properties of Bacillus thuringiensis toxins to cotton pink bollworm ( Pectinophora gossypiella ) and cotton bollworm ( Helicoverpa zea ) were investigated. P. gossypiella was susceptible to Cry1Aa, Cry1Ab, Cry1Ac, and Cry2Aa toxins. To H. zea , Cry1Ac and Cry1Ab were more potent than Cry1Aa and Cry2Aa. Cry1Ba, Cry1Ca, Cry1Da, Cry1Ea, Cry1Fa, Cry1Ga, Cry1Ha, and Cry2Ba were not potent against both pests. Binding assays were performed with 125 I-labeled toxins (Cry1Aa, Cry1Ab, Cry1Ac, and Cry2Aa) and brush border membrane vesicles (BBMVs) prepared from H. zea and P. gossypiella midguts. Both Cry1Ab and Cry1Ac toxins showed saturable, high-affinity binding to P. gossypiella and H. zea BBMVs. Cry2Aa and Cry1Aa toxins bound to BBMVs with relatively low binding affinity but with high binding site concentration. Heterologous competition binding assays were performed to investigate the binding site cross reactivity. The results showed that Cry1Aa, Cry1Ab, and Cry1Ac recognize the same binding site, which is different from Cry2Aa. Ligand blot assay showed that Cry1Ac toxin binds to a 120-kDa BBMV protein in P. gossypiella and Cry1Ab binds to a major 210-kDa protein.}, number={3}, journal={PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY}, author={Karim, S and Riazuddin, S and Gould, F and Dean, DH}, year={2000}, month={Jul}, pages={198–216} }
 @article{cohen_romena_gould_2000, title={Dispersal by larvae of the stem borers Scirpophaga incertulas (Lepidoptera : Pyralidae) and Chilo suppressalis (Lepidoptera : Crambidae) in plots of transplanted rice}, volume={29}, ISSN={["1938-2936"]}, DOI={10.1603/0046-225X-29.5.958}, abstractNote={We studied larval dispersal behavior of two rice stem borers, Scirpophaga incertulas (Walker) and Chilo suppressalis (Walker), to evaluate the potential of seed mixtures for resistance management in B. thuringiensis (Bt) rice. Both species showed extensive movement among plants (or “hills”) in plots of transplanted rice, during the course of larval development. On rice plants at the vegetative stage, almost all S. incertulas larvae dispersed on the day of eclosion. On plants at booting stage, most S. incertulas bored into hills on which egg masses were placed (referred to as the “release hill”). Almost all neonate C. suppressalis also bored into the release hill, at both vegetative and booting stages. At both rice growth stages, most larvae of both species dispersed to new hills between 7 and 18 d after eclosion. Both S. incertulas and C. suppressalis moved among tillers within the release hill, as indicated by an increase in dispersion among tillers over time. The distance and direction of dispersal of ballooning S. incertulas larvae was influenced by wind speed and direction. Larval recovery within plots generally declined rapidly over the first 5 d after egg hatch and then more slowly thereafter. Because many S. incertulas and C. suppressalis larvae move among tillers within hills and among hills within plots, many larvae in plots planted to seed mixtures will consume tissue from both Bt and non-Bt plants. This behavior will reduce the cumulative dose of toxin ingested and can accelerate the evolution of resistance.}, number={5}, journal={ENVIRONMENTAL ENTOMOLOGY}, author={Cohen, MB and Romena, AM and Gould, F}, year={2000}, month={Oct}, pages={958–971} }
 @article{bentur_andow_cohen_romena_gould_2000, title={Frequency of alleles conferring resistance to a Bacillus thuringiensis toxin in a Philippine population of Scirpophaga incertulas (Lepidoptera : Pyralidae)}, volume={93}, ISSN={["1938-291X"]}, DOI={10.1603/0022-0493-93.5.1515}, abstractNote={Using the F2 screen methodology, we estimated the frequency of alleles conferring resistance to the Cry1Ab toxin of Bacillus thuringiensis Berliner in a Philippine population of the stem borer Scirpophaga incertulas (Walker). Evaluation of >450 isofemale lines for survival of F2 larvae on cry1Ab plants did not detect the presence of an allele conferring a high level of resistance. The frequency of such an allele in the sampled population was conservatively estimated to be <3.6 x 10(-3) with 95% confidence and a detection probability of 94%. However, there was evidence of the presence of alleles conferring partial resistance to Cry1Ab. The frequency of alleles for partial resistance was estimated as 4.8 x 10(-3) with a 95% CI between 1.3 x 10(-3) and 1.04 x 10(-2) and a detection probability of 94%. Our results suggest that the frequency of alleles conferring resistance to Cry1Ab in the population of S. incertulas sampled is not too high to preclude successful implementation of the high dose/refuge resistance management strategy.}, number={5}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Bentur, JS and Andow, DA and Cohen, MB and Romena, AM and Gould, F}, year={2000}, month={Oct}, pages={1515–1521} }
 @article{alinia_cohen_gould_2000, title={Heritability of tolerance to the Cry1Ab toxin of Bacillus thuringiensis in Chilo suppressalis (Lepidoptera : Crambidae)}, volume={93}, ISSN={["0022-0493"]}, DOI={10.1603/0022-0493-93.1.14}, abstractNote={Heritability of Chilo suppressalis (Walker) tolerance to the Cry1Ab toxin of Bacillus thuringiensis Berliner was estimated using a half-sibling design. Artificial diet with and without Cry1Ab was infested with progenies of 20 males, each mated with 2 females, and mortality was scored 5 d after infestation. The progeny of each female was reared and scored separately. Mean mortality of the 20 families on the Cry1Ab diet was 46.5%. The effects of both male parent and of female parent within male parent were significant. Heritability was estimated to be 0.52, suggesting that a high proportion of phenotypic variation was because of genetic differences. Mortality on the Cry1Ab diet was not correlated with mortality on control diet, indicating that differences among families in tolerance to Cry1Ab were not attributable to differences in general fitness. Our results indicate that "high dose" Bt rice plants may be particularly important for Cry1Ab resistance management in C. suppressalis populations.}, number={1}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Alinia, F and Cohen, MB and Gould, F}, year={2000}, month={Feb}, pages={14–17} }
 @misc{roe_bailey_gould_kennedy_2000, title={Insecticide resistance assay}, volume={6,060,039}, number={2000 May 9}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Roe, R. M. and Bailey, W. D. and Gould, F. and Kennedy, G. G.}, year={2000} }
 @article{dirie_cohen_gould_2000, title={Larval dispersal and survival of Scirpophaga incertulas (Lepidoptera : Pyralidae) and Chilo suppressalis (Lepidoptera : Crambidae) on cry1Ab-transformed and non-transgenic rice}, volume={29}, ISSN={["0046-225X"]}, DOI={10.1603/0046-225X-29.5.972}, abstractNote={Abstract Sowing seed mixtures of transgenic and nontransgenic plants is one approach to establishing refuges for resistance management of crops transformed with Bacillus thuringiensis (Bt) toxins. We studied larval dispersal and survival of two rice stem borers, Scirpophaga incertulas (Walker) and Chilo suppressalis (Walker), to evaluate the potential effectiveness of seed mixtures for resistance management of Bt rice, Oryza sativa L. Experiments were conducted with two cry1Ab-transformed rice varieties, ‘IR58’ and ‘Tarom Molaii’, and corresponding nontransgenic controls. During 0–24 and 24–48 h after egg hatch, the proportion of C. suppressalis larvae dispersing from the natal plant did not differ between transgenic and control plants for either rice variety. Dispersal by S. incertulas did not differ between transgenic and control plants of IR58 during either 0–24 or 24–48 h, but a greater proportion of S. incertulas larvae dispersed from transgenic Tarom Molaii than from control plants 24–48 h after ecl...}, number={5}, journal={ENVIRONMENTAL ENTOMOLOGY}, author={Dirie, AM and Cohen, MB and Gould, F}, year={2000}, month={Oct}, pages={972–978} }
 @article{schliekelman_gould_2000, title={Pest control by the introduction of a conditional lethal trait on multiple loci: Potential, limitations, and optimal strategies}, volume={93}, ISSN={["0022-0493"]}, DOI={10.1603/0022-0493-93.6.1543}, abstractNote={Advances in genetics have made it feasible to genetically engineer insect strains carrying a conditional lethal trait on multiple loci. We model the release into a target pest population of insects carrying a dominant and fully penetrant conditional lethal trait on 1-20 loci. Delaying the lethality for several generations after release allows the trait to become widely spread in the target population before being activated. To determine effectiveness and optimal strategies for such releases, we vary release size, number of generations until the conditional lethality, nonconditional fitness cost resulting from gene insertions, and fitness reduction associated with laboratory rearing. We show that conditional lethal releases are potentially orders of magnitude more effective than sterile male releases of equal size, and that far smaller release sizes may be required for this approach than necessary with sterile males. For example, a release of male insects carrying a conditional lethal allele that is activated in the F4 generation on 10 loci reduces the target populatioin to 10(-4) of no-release size if there are initially two released males for every wild male. We show how the effectiveness of conditional lethal releases decreases as the nonconditional fitness reduction (i.e., fitness reduction before the trait becomes lethal) associated with the conditional lethal genes increases. For example, if there is a 5% nonconditional fitness cost per conditional lethal allele, then a 2:1 (released male:wild male) release with conditional lethal alleles that are activated in the F4 generation reduces the population to 2-5% (depending on the degree of density dependence) of the no-release size. If there is a per-allele reduction in fitness, then as the number of loci is increased there is a trade-off between the fraction of offspring carrying at least one conditional lethal allele and the fitness of the released insects. We calculate the optimal number of loci on which to insert the conditional lethal gene given various conditions. In addition, we show how laboratory-rearing fitness costs, density-dependence, and all-male versus male-female releases affect the efficiency of conditional lethal releases.}, number={6}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Schliekelman, P and Gould, F}, year={2000}, month={Dec}, pages={1543–1565} }
 @article{schliekelman_gould_2000, title={Pest control by the release of insects carrying a female-killing allele on multiple loci}, volume={93}, ISSN={["0022-0493"]}, DOI={10.1603/0022-0493-93.6.1566}, abstractNote={With recent advances in genetics, many new strategies for pest control have become feasible. This is the second article in which we model new techniques for pest control based on the mass release of genetically modified insects. In this article we model the release of insects carrying a dominant and redundant female killing or sterilizing (FK) allele on multiple genetic loci. If such insects are released into a target population, the FK allele can become widely spread in the population through the males while reducing the population each generation by killing females. We allow the number of loci used to vary from 1 to 20. We also allow the FK allele to carry a fitness cost in males due to the gene insertions. Using a model, we explore the effectiveness and optimal strategies for such releases. In the most ideal circumstances (no density-dependence and released insects equal in fitness to wild ones), FK releases are several orders of magnitude more effective than equal sized sterile male releases. For example, a single release of 19 FK-bearing males for every two wild males, with the released males carrying the FK allele on 10 loci, reduces the target population to 0.002% of no-release size. An equal sized sterile release reduces the target population to 5% of no-release size. We also show how the effectiveness of the technique decreases as the fitness cost of the FK alleles in males increases. For example, the above mentioned release reduces the target population to 0.7% of no-release size if each FK allele carries a fitness cost in males of 5%. Adding a simple model for density-dependence and assuming that each of the released males carries the FK allele on six loci, we show that the release size necessary to reduce the target population to 1/100 of no-release size in 10 generations of releases varies from 0.44:1 to 4:1 (depending on parameter values). We also calculate the optimal number of loci on which to put the FK allele under various circumstances.}, number={6}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Schliekelman, P and Gould, F}, year={2000}, month={Dec}, pages={1566–1579} }
 @article{gould_schliekelman_2000, title={Reassessing autocidal pest control}, ISBN={0890542465}, journal={Emerging technologies for integrated pest management : concepts, research, and implementation}, publisher={St. Paul, MN : APS Press,}, author={Gould, F. and Schliekelman, P.}, year={2000}, pages={190} }
 @article{gould_cohen_2000, title={Sustainable use of genetically modified crops in developing countries}, journal={Agricultural biotechnology and the poor: proceedings of an international  conference, Washington, DC, USA, 21-22 October, 1999}, publisher={Washington, D.C. :  Consultative Group on International Agricultural Research,}, author={Gould, F. and Cohen, M. B.}, year={2000}, pages={139} }
 @article{bernays_oppenheim_chapman_kwon_gould_2000, title={Taste sensitivity of insect herbivores to deterrents is greater in specialists than in generalists: A behavioral test of the hypothesis with two closely related caterpillars}, volume={26}, ISSN={["1573-1561"]}, DOI={10.1023/A:1005430010314}, number={2}, journal={JOURNAL OF CHEMICAL ECOLOGY}, author={Bernays, EA and Oppenheim, S and Chapman, RF and Kwon, H and Gould, F}, year={2000}, month={Feb}, pages={547–563} }
 @article{gould_2000, title={Testing Bt refuge strategies in the field}, volume={18}, ISSN={["1087-0156"]}, DOI={10.1038/73693}, number={3}, journal={NATURE BIOTECHNOLOGY}, author={Gould, F}, year={2000}, month={Mar}, pages={266–267} }
 @article{bentur_cohen_gould_2000, title={Variation in performance on cry1Ab-transformed and nontransgenic rice varieties among populations of Scirpophaga incertulas (Lepidoptera : Pyralidae) from Luzon Island, Philippines}, volume={93}, ISSN={["0022-0493"]}, DOI={10.1603/0022-0493-93.6.1773}, abstractNote={We quantified variation in performance under greenhouse conditions among seven populations of Scirpophaga incertulas (Walker) from Luzon Island, Philippines, on three rice varieties: 'IR58' transformed with the cry1Ab gene from Bacillus thuringiensis Berliner, and nontransgenic IR58 and IR62. On IR62, S. incertutas performance did not differ among provinces for any of the 10 parameters measured, but there was a significant effect of town within province for one parameter, 20-d-old larval weight. Larval survival after 48 h on cy1Ab-transformed IR58 did not differ significantly among provinces, but did differ significantly among towns within a province. There was no geographic variation in larval survival after 48 h on control plants of IR58. Surviving insects from the cry1Ab-transformed IR58 were transferred to IR62 to complete development. There was no geographic variation in the percentage of insects completing development to adult emergence and the time required by the transferred female insects to complete development. However, there was variation among provinces in male developmental time. The absence of geographic variation on nontransgenic IR58 and the very limited variation on IR62 indicated that there was little variation in general vigor among the S. incertulas populations and thus that the variation in performance oil cry1Ab-transformed IR58 was probably attributable to differences in susceptibility to Cry1Ab.}, number={6}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Bentur, JS and Cohen, MB and Gould, F}, year={2000}, month={Dec}, pages={1773–1778} }
 @article{peck_ellner_gould_2000, title={Varying migration and deme size and the feasibility of the shifting balance}, volume={54}, ISSN={["0014-3820"]}, DOI={10.1111/j.0014-3820.2000.tb00035.x}, abstractNote={EvolutionVolume 54, Issue 1 p. 324-327 Free Access VARYING MIGRATION AND DEME SIZE AND THE FEASIBILITY OF THE SHIFTING BALANCE Steven L. Peck, Steven L. Peck USDA/ARS, Tropical Fruit and Vegetable Research Laboratory, P.O. Box 4459, Hilo, Hawaii 96720 E-mail: sp@aloha.net Present address: Zoology Department, Brigham Young University, Provo, Utah 84602–5255; E-mail: steven_peck@byu.edu.Search for more papers by this authorStephen P. Ellner, Stephen P. Ellner Biomathematics Graduate Program, Department of Statistics, North Carolina State University, Raleigh, North Carolina 27695–8203 E-mail: ellner@stat.ncsu.eduSearch for more papers by this authorFred Gould, Fred Gould Department of Entomology, North Carolina State University, Raleigh, North Carolina 27695–7634 E-mail: fgould@unity.ncsu.eduSearch for more papers by this author Steven L. Peck, Steven L. Peck USDA/ARS, Tropical Fruit and Vegetable Research Laboratory, P.O. Box 4459, Hilo, Hawaii 96720 E-mail: sp@aloha.net Present address: Zoology Department, Brigham Young University, Provo, Utah 84602–5255; E-mail: steven_peck@byu.edu.Search for more papers by this authorStephen P. Ellner, Stephen P. Ellner Biomathematics Graduate Program, Department of Statistics, North Carolina State University, Raleigh, North Carolina 27695–8203 E-mail: ellner@stat.ncsu.eduSearch for more papers by this authorFred Gould, Fred Gould Department of Entomology, North Carolina State University, Raleigh, North Carolina 27695–7634 E-mail: fgould@unity.ncsu.eduSearch for more papers by this author First published: 09 May 2007 https://doi.org/10.1111/j.0014-3820.2000.tb00035.xCitations: 17 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume54, Issue1February 2000Pages 324-327 ReferencesRelatedInformation}, number={1}, journal={EVOLUTION}, author={Peck, SL and Ellner, SP and Gould, F}, year={2000}, month={Feb}, pages={324–327} }
 @article{roe_bailey_zhao_young_carter_gould_sorenson_kennedy_bacheler_1999, title={Assay kit for species and insecticide resistance diagnosis for tobacco budworm and bollworm in cotton}, number={1999}, journal={Beltwide Cotton Conferences. Proceedings}, author={Roe, R. M. and Bailey, W.D. and Zhao, G. and Young, H.P. and Carter, L.M. and Gould, F. and Sorenson, C.E. and Kennedy, G.G. and Bacheler, J.S.}, year={1999}, pages={926–930} }
 @article{storer_gould_kennedy_peck_van duyn_1999, title={Evolution of region-wide resistance in cotton bollworm to Bt cotton as influenced by Bt corn: Identification of key factors through computer simulation}, volume={2}, number={1999}, journal={Beltwide Cotton Conferences. Proceedings}, author={Storer, N. P. and Gould, F. and Kennedy, G. G. and Peck, S. L. and Van Duyn, J. W.}, year={1999}, pages={952–956} }
 @article{martinez-ramirez_gould_ferre_1999, title={Histopathological effects and growth reduction in a susceptible and a resistant strain of Heliothis virescens (Lepidoptera : Noctuidae) caused by sublethal doses of pure Cry1A crystal proteins from Bacillus thuringiensis}, volume={9}, ISSN={["0958-3157"]}, DOI={10.1080/09583159929811}, abstractNote={Two strains of the tobacco budworm Heliothis virescens, one selected in the laboratory for resistance to Cry1Ac crystal protein from Bacillus thuringiensis (for which the mechanism of resistance was not associated with reduced binding) and an unselected control strain, were exposed to sublethal doses of pure Cry1A crystal proteins. A histopathological study was conducted to determine the epithelial damage caused by ingestion of Cry1Ac. Tissue sections of the midgut were obtained after 20, 40 and 60 min of toxin ingestion. Histopathological changes were observed primarily in columnar cells and were time-dependent. However, essentially the same level of damage was observed in the two strains. Toxin feeding tests with Cry1Ac and Cry1Ab, indicated that the toxins retarded growth and inhibited food intake of susceptible larvae, but did not significantly affect larvae of the resistant strain. Since the histopathological damage was similar in both strains, it appears that resistant larvae could repair (or substi...}, number={2}, journal={BIOCONTROL SCIENCE AND TECHNOLOGY}, author={Martinez-Ramirez, AC and Gould, F and Ferre, J}, year={1999}, month={Jun}, pages={239–246} }
 @article{lee_you_gould_dean_1999, title={Identification of residues in domain III of Bacillus thuringiensis Cry1Ac toxin that affect binding and toxicity}, volume={65}, number={10}, journal={Applied and Environmental Microbiology}, author={Lee, M. K. and You, T. H. and Gould, F. L. and Dean, D. H.}, year={1999}, pages={4513–4520} }
 @article{kota_daniell_varma_garczynski_gould_moar_1999, title={Overexpression of the Bacillus thuringiensis (Bt) Cry2Aa2 protein in chloroplasts confers resistance to plants against susceptible and Bt-resistant insects}, volume={96}, ISSN={["0027-8424"]}, DOI={10.1073/pnas.96.5.1840}, abstractNote={Evolving levels of resistance in insects to the bioinsecticide Bacillus thuringiensis (Bt) can be dramatically reduced through the genetic engineering of chloroplasts in plants. When transgenic tobacco leaves expressing Cry2Aa2 protoxin in chloroplasts were fed to susceptible, Cry1A-resistant (20,000- to 40,000-fold) and Cry2Aa2-resistant (330- to 393-fold) tobacco budworm Heliothis virescens , cotton bollworm Helicoverpa zea , and the beet armyworm Spodoptera exigua , 100% mortality was observed against all insect species and strains. Cry2Aa2 was chosen for this study because of its toxicity to many economically important insect pests, relatively low levels of cross-resistance against Cry1A-resistant insects, and its expression as a protoxin instead of a toxin because of its relatively small size (65 kDa). Southern blot analysis confirmed stable integration of cry 2Aa2 into all of the chloroplast genomes (5,000–10,000 copies per cell) of transgenic plants. Transformed tobacco leaves expressed Cry2Aa2 protoxin at levels between 2% and 3% of total soluble protein, 20- to 30-fold higher levels than current commercial nuclear transgenic plants. These results suggest that plants expressing high levels of a nonhomologous Bt protein should be able to overcome or at the very least, significantly delay, broad spectrum Bt-resistance development in the field.}, number={5}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Kota, M and Daniell, H and Varma, S and Garczynski, SF and Gould, F and Moar, WJ}, year={1999}, month={Mar}, pages={1840–1845} }
 @article{peck_gould_ellner_1999, title={Spread of resistance in spatially extended regions of transgenic cotton: Implications for management of Heliothis virescens (Lepidoptera: Noctuidae)}, volume={92}, DOI={10.1093/jee/92.1.1}, abstractNote={Through the use of a stochastic, spatially explicit, simulation model, we explored factors that may influence the regional development of resistance in Heliothis virescens (F.) to a Bacillus thuringiensis (Bt) δ-endotoxin in transgenic cotton. The model represents the age structure of adults and larvae, plant to plant movement of larvae within a field, migration of adults among fields, plant type-genotype specific selection, and development time. We find that the spatial scale and the temporal pattern of refuges can have a strong effect on the development of resistance to B. thuringiensis in transgenic cotton. The time to resistance was in general significantly longer in regions where the same fields were used as a refuge year after year, compared with regions where the refuge fields are changed randomly from year to year. Spring movement of emerging adults onto wild hosts delays resistance if the movement is far enough from the field in which pupae overwintered. Increases in the summer migration rate and the distance moved delayed resistance development up to a point at which higher rates do not further delay resistance. Refuges were an effective strategy for delaying resistance. We found that delays in larval development time on Bt cotton may either increase or decrease the rate of resistance development, depending on complex interactions with the length of the growing season. Larval movement between Bt and non-Bt plants was found to increase the rate at which resistance developed, but this may be ameliorated with increasing mortality costs associated with larval movement.}, number={1}, journal={Journal of Economic Entomology}, author={Peck, S. L. and Gould, F. and Ellner, S. P.}, year={1999}, pages={1–16} }
 @article{sisterson_gould_1999, title={The inflated calyx of Physalis angulata: A refuge from parasitism for Heliothis subflexa}, volume={80}, ISSN={["0012-9658"]}, DOI={10.2307/177040}, number={3}, journal={ECOLOGY}, author={Sisterson, MS and Gould, FL}, year={1999}, month={Apr}, pages={1071–1075} }
 @article{peck_ellner_gould_1998, title={A spatially explicit stochastic model demonstrates the feasibility of Wright's Shifting Balance Theory}, volume={52}, ISSN={["1558-5646"]}, DOI={10.2307/2411353}, number={6}, journal={EVOLUTION}, author={Peck, SL and Ellner, SP and Gould, F}, year={1998}, month={Dec}, pages={1834–1839} }
 @article{theunis_aguda_cruz_decock_peferoen_lambert_bottrell_gould_litsinger_cohen_1998, title={Bacillus thuringiensis isolates from the Philippines: habitat distribution, delta-endotoxin diversity, and toxicity to rice stem borers (Lepidoptera : Pyralidae)}, volume={88}, ISSN={["0007-4853"]}, DOI={10.1017/S0007485300025955}, abstractNote={Abstract Bacillus thuringiensis Berliner isolates were detected in 57% of 801 samples of rice grain dust, soil, rice field arthropods, and miscellaneous habitats (rice straw compost and mammal faeces) collected at 100 sites in the Philippines. The collection yielded 3950 isolates of B. thuringiensis (8.7 isolates/positive sample). Grain dust from rice mills was the richest source (63% of the samples were positive, with 10.2 isolates/positive sample), followed by rice field arthropods, soil, and miscellaneous habitats. Polyclonal antibodies to six δ-endotoxin groups (Cry1A, Cry1B, Cry1C, Cry1D, Cry1E, and Cry3A) were used in enzyme-linked immunosorbent assays (ELISA) to characterize the toxins produced by each isolate. Subsamples of isolates representing the diversity of isolate sources and δ-endotoxin profiles were bioassayed against the yellow stem borer, Scirpophaga incertulas (Walker) and striped stem borer, Chilo suppressalis (Walker). Eighteen isolates highly toxic to both species were selected for characterization of δ-endotoxin genes by polymerase chain reaction (PCR) with primers specific to 14 genes or gene subfamilies, and Western blotting with Cry2A antibodies. At least two novel δ-endotoxin genes, related to cry1B and cry1F , were detected by DNA sequencing of PCR products.}, number={3}, journal={BULLETIN OF ENTOMOLOGICAL RESEARCH}, author={Theunis, W and Aguda, RM and Cruz, WT and Decock, C and Peferoen, M and Lambert, B and Bottrell, DG and Gould, FL and Litsinger, JA and Cohen, MB}, year={1998}, month={Jun}, pages={335–342} }
 @article{lambert_bradley_gould_van duyn_1998, title={Bollworm (Helicoverpa zea): adaptation to BT toxin?}, volume={2}, number={1998}, journal={Beltwide Cotton Conferences. Proceedings}, author={Lambert, A. L. and Bradley, J. R., Jr. and Gould, F. and Van Duyn, J. W.}, year={1998}, pages={1033–1037} }
 @article{mcgaughey_gould_gelernter_1998, title={Bt resistance management}, volume={16}, ISSN={["1087-0156"]}, DOI={10.1038/nbt0298-144}, number={2}, journal={NATURE BIOTECHNOLOGY}, author={McGaughey, WH and Gould, F and Gelernter, W}, year={1998}, month={Feb}, pages={144–146} }
 @article{onstad_gould_1998, title={Do dynamics of crop maturation and herbivorous insect life cycle influence the risk of adaptation to toxins in transgenic host plants?}, volume={27}, ISSN={["0046-225X"]}, DOI={10.1093/ee/27.3.517}, abstractNote={Because host-plant chemistry is dynamic, chemical defenses are dynamic, and senescence in plants causes many proteins to decompose after flowering, laboratory and field studies on transgenic crops performed over only part of a plant generation or part of a season may not provide sufficient data to evaluate strategies for resistance management. As an example, we focused on the recent introduction of transgenic corn to control European corn borer, Ostrinia nubilalis (Hubner) (Lepidoptera: Pyralidae). We gathered data from literature on the life cycle of European corn borer and corn crop maturation to study the role that phenological relationships may play in resistance evolution. In addition, we simulated hypothetical titer declines resulting in increased survival in European corn borer populations infesting transgenic corn using a model of population dynamics and genetics. The relationship between European corn borer hatching period and corn maturation varies greatly from site to site and year to year. The peak of the hatching period in the late summer generation of the European corn borer occurs at or after the average midpoint of the dough stage of corn. The last larvae tend to hatch after the dough stage is past and after the midpoint of the dent stage. In simulations where 5% of a region is planted with nontransgenic corn in separate refuge plots and 95% is planted with transgenic corn, complete loss of titer as a result of senescence produces resistance at the 3% resistance-allele level after 5–42 yr, which is less than the 83 yr predicted by the standard model for resistance development when the transgenic corn loses no titer as a result of senescence. We hypothesize that genetically engineered toxins will often decrease in leaf and stem titer as crops reach maturation. The insects feeding and surviving on a crop during its senescence may have important consequences for the population genetics of the breakdown of host plant resistance.}, number={3}, journal={ENVIRONMENTAL ENTOMOLOGY}, author={Onstad, DW and Gould, F}, year={1998}, month={Jun}, pages={517–522} }
 @article{bailey_zhao_carter_gould_kennedy_roe_1998, title={Feeding disruption bioassay for species and Bacillus thuringiensis resistance diagnosis for Heliothis virescens and Helicoverpa zea in cotton (Lepidoptera : Noctuidae)}, volume={17}, ISSN={["1873-6904"]}, DOI={10.1016/S0261-2194(98)00057-X}, abstractNote={Bioassay methodology was developed for species diagnosis of Heliothis virescens compared with Helicoverpa zea in cotton and to detect H. virescens larvae with significant levels of resistance to the biopesticide, Bacillus thuringiensis. The assay end-point is feeding disruption, which is measured by a lack of fecal production by larvae exposed to a diagnostic dose of CrylAc in a blue indicator diet. In laboratory tests, the bioassay accurately distinguished neonates of H. zea from H. virescens and was able to detect B. thuringiensis resistance in H. virescens. The assay is rapid compared with mortality assays and should be inexpensive. The assay should also be adaptable to current cotton integrated pest management programs and sampling techniques and detect most physiological mechanisms of B. thuringiensis resistance. The potential utility of the feeding disruption assay in cotton integrated pest management and with other crops, insect pests and insecticides is discussed. The studies reported here were conducted on laboratory strains of B. thuringiensis susceptible H. virescens and H. zea and a highly B. thuringiensis-resistant laboratory strain of H. virescens (YHD2) originally collected in North Carolina.}, number={7}, journal={CROP PROTECTION}, author={Bailey, WD and Zhao, G and Carter, LM and Gould, F and Kennedy, GG and Roe, RM}, year={1998}, month={Sep}, pages={591–598} }
 @article{riggin-bucci_gould_white_1998, title={Increased ovipositional attractancy to surfactant-treated broccoli by the diamondback moth (Lepidoptera : Plutellidae): Tests of potential mechanisms}, volume={33}, ISSN={["0749-8004"]}, DOI={10.18474/0749-8004-33.3.261}, abstractNote={Studies were conducted to investigate potential mechanisms by which treatment of broccoli leaves with the surfactant Latron CS-7® causes increased diamondback moth, Plutella xylostella (L.), oviposition. The importance of vision on oviposition was investigated by use of choice and no-choice tests conducted in the presence of light and in complete darkness. Females oviposited 10.7 and 12.8 times as many eggs on treated plants relative to nontreated plants in the presence and absence of light, respectively, indicating that females do not prefer treated plants based solely on visual cues. Greenhouse studies showed that moths continue to lay significantly more eggs on surfactant-treated plants up to 3 d after initial treatment of plants with Latron CS-7. No difference was observed in larval development or survival on treated versus nontreated plants. Scanning electron microscopy indicated a dramatic difference in wax crystallite morphology of surfactant-treated plants relative to nontreated plants. Ovipositional attractancy of surfactant-treated leaves to diamondback moths could be due to a change in mechanoreceptor cues on the leaf surface or volatile compounds released from the leaf surface as a result of altered plant wax micromorphology.}, number={3}, journal={JOURNAL OF ENTOMOLOGICAL SCIENCE}, author={Riggin-Bucci, TM and Gould, F and White, C}, year={1998}, month={Jul}, pages={261–269} }
 @misc{bottrell_barbosa_gould_1998, title={Manipulating natural enemies by plant variety selection and modification: A realistic strategy?}, volume={43}, ISSN={["1545-4487"]}, DOI={10.1146/annurev.ento.43.1.347}, abstractNote={The host plants of arthropod pests may affect parasitoids and predators directly or indirectly, through multitrophic interactions. Direct plant effects may involve simple mechanisms such as reduced parasitoid searching efficiency caused by trichomes. Multitrophic effects often involve complex interactions that are not well understood, and their impact on natural enemies and biological control are difficult to predict. Knowledge of the direct and multitrophic effects creates opportunities to increase the effectiveness of natural enemies by incorporating natural enemy-enhancing traits into crop plants. The strategy may have potential for both generalist and specialist natural enemies, but the enemies' behavior and other factors will affect the results. Although combining natural enemies and plant resistance may slow the adaptation of some insect pests, it may speed up adaptations of others. A better understanding of plant/pest/natural enemy evolution is necessary to predict how to combine natural enemies and plant resistance for the best long-term results.}, journal={ANNUAL REVIEW OF ENTOMOLOGY}, author={Bottrell, DG and Barbosa, P and Gould, F}, year={1998}, pages={347–367} }
 @article{onstad_gould_1998, title={Modeling the dynamics of adaptation to transgenic maize by European corn borer (Lepidoptera : Pyralidae)}, volume={91}, ISSN={["1938-291X"]}, DOI={10.1093/jee/91.3.585}, abstractNote={A deterministic population dynamics model was modified to include single-locus, 2-allele genetics to simulate strategies for delaying resistance in the European corn borer, Ostrinia nubilalis (Hübner), population to transgenic maize. We evaluated seed mixtures of transgenic and nontransgenic maize, 2-row strips of non transgenic plants, adjacent but separate refuges of nontransgenic maize, and rotation of nontransgenic and transgenic maize. We studied how the choice of hybrid, planting time, and weather may influence the selection of a tactic for delaying resistance to transgenic maize. Our results indicate that separate refuges are superior to seed mixtures for delaying resistance. If a high toxin dose cannot be achieved and a small fraction of homozygous susceptible and heterozygous European corn borer neonates survive on transgenic maize, then resistance can develop in 10-33% of the time required under the assumption of a successful high dose that kills all heterozygous neonates. Planting 2-row strips may be as good as separate refuges in delaying resistance, but their adoption carries greater risk because of the uncertainty surrounding movement and survival of neonates. The use of transgenic hybrids is the same whether or not they express the toxin gene in silks and kernels of maize ears. Toxin titer decline must be studied because our simulations indicate that development of resistance may be greatly hastened by this process.}, number={3}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Onstad, DW and Gould, F}, year={1998}, month={Jun}, pages={585–593} }
 @misc{gould_1998, title={Nature wars: People vs. Pests, by M.L. Winston}, volume={14}, number={3}, journal={Issues in Science and Technology}, author={Gould, F. L.}, year={1998}, pages={86} }
 @misc{gould_1998, title={Sustainability of transgenic insecticidal cultivars: Integrating pest genetics and ecology}, volume={43}, ISSN={["1545-4487"]}, DOI={10.1146/annurev.ento.43.1.701}, abstractNote={This review examines potential impacts of transgenic cultivars on insect population dynamics and evolution. Experience with classically bred, insecticidal cultivars has demonstrated that a solid understanding of both the target insect's ecology and the cultivar's performance under varied field conditions will be essential for predicting area-wide effects of transgenic cultivars on pest and natural enemy dynamics. This experience has also demonstrated the evolutionary capacity of pests for adaptive response to insecticidal traits in crops. Biochemical and genetic studies of insect adaptation to the Bacillus thuringiensis (Bt) toxins expressed by currently marketed transgenic cultivars indicate a high risk for rapid adaptation if these cultivars are misused. Theoretical and practical issues involved in implementing strategies to delay pest adaptation to insecticidal cultivars are reviewed. Emphasis is placed on examining the "high dose"/refuge strategy that has become the goal of industry and regulatory authorities.}, journal={ANNUAL REVIEW OF ENTOMOLOGY}, author={Gould, F}, year={1998}, pages={701–726} }
 @article{lee_aguda_cohen_gould_dean_1997, title={Determination of binding of Bacillus thuringiensis delta-endotoxin receptors to rice stem borer midguts}, volume={63}, number={4}, journal={Applied and Environmental Microbiology}, author={Lee, M. K. and Aguda, R. M. and Cohen, M. B. and Gould, F. L. and Dean, D. H.}, year={1997}, pages={1453–1459} }
 @article{johnson_gould_kennedy_1997, title={Effect of an entomopathogen on adaptation of Heliothis virescens populations to transgenic host plants}, volume={83}, ISSN={["0013-8703"]}, DOI={10.1046/j.1570-7458.1997.00165.x}, abstractNote={The role of an entomopathogen in evolution of herbivore adaptation to partially resistant host plants was examined using a tritrophic system in the laboratory. We hypothesized that a pathogen should interact with herbivore behavior to accelerate herbivore adaptation to toxic plants: individuals not adapted to toxin tend to move more on toxic plants, and therefore are more likely to encounter a lethal dose of pathogen, further increasing the probability that they will be eliminated by selection. Heliothis virescens (F.) (Noctuidae) was selected for adaptation to transgenic tobacco containing a sublethal concentration of Bacillus thuringiensis Berliner toxin under two treatment regimes: larvae placed on plants treated with infective conidia of the entomopathogenic fungus, Nomuraea rileyi (Farlow) Samson, and larvae placed on plants without fungus. Selection was initiated with a genetically heterogeneous strain created by crossing two laboratory strains of H. virescens, one not adapted to B. thuringiensis toxin, and one highly adapted (>1000-fold) to toxin. This cross was performed four times to create four independent populations. Selection was initiated with F2 offspring from each cross and continued for 8–10 consecutive generations. Adaptation to toxin within each treatment population was quantified every generation by measuring survival and growth of larvae on artificial diet containing a low concentration of B. thuringiensis toxin. In three of four replicates, H. virescens populations exposed to N. rileyi adapted to B. thuringiensis toxin more quickly than populations not exposed. These results supported our hypothesis that the pathogen should accelerate adaptation to toxic plants. However, this hypothesis was contradicted by the result in one replicate, in which the population not exposed to fungus adapted to toxic plants faster. This opposite result could not be explained, but it suggests that there may be substantial variation in herbivore evolution in tritrophic systems. H. virescens populations selected in the presence of fungus and in the absence of fungus did not differ in feeding or in mortality when placed on leaf disks treated with conidia. Thus, populations exposed to N. rileyi on plants for 7–8 generations displayed neither physiological nor behavioral adaptation to N. rileyi.}, number={2}, journal={ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA}, author={Johnson, MT and Gould, F and Kennedy, GG}, year={1997}, month={May}, pages={121–135} }
 @article{johnson_gould_kennedy_1997, title={Effects of natural enemies on relative fitness of Heliothis virescens genotypes adapted and not adapted to resistant host plants}, volume={82}, ISSN={["0013-8703"]}, DOI={10.1046/j.1570-7458.1997.00133.x}, abstractNote={We investigated the potential of two natural enemies of Heliothis virescens (F.) (Noctuidae) to affect its rate of adaptation to tobacco containing Bacillus thuringiensis Berliner toxin. Larval fitness of two laboratory strains of H. virescens, one adapted to B. thuringiensis toxin and one not adapted, was compared on toxic and nontoxic plants, in the presence of the parasitoid Campoletis sonorensis (Cameron) (Ichneumonidae) or the entomopathogenic fungus Nomuraea rileyi (Farlow) Samson. By exposing larvae to plants and enemies for no more than 24 h, we focussed on the behavioral rather than physiological component of their interaction with toxic plants and natural enemies.



Parasitism of H. virescens larvae by C. sonorensis during exposure periods of 1–4 h was lower on toxic plants than nontoxic plants and was lower for nonadapted larvae than for toxin-adapted larvae. Decreased larval feeding damage on toxic versus nontoxic plants, and by nonadapted versus adapted larvae, may explain differences in parasitism, because C. sonorensis locates host larvae using cues from damaged plants. Effects of plant toxicity and larval strain on H. virescens survival were numerically consistent with effects on parasitism, but they were not statistically significant. When mean larval survival is used to estimate fitness of the nonadapted genotype relative to the toxin-adapted genotype, we find that C. sonorensis is expected to delay adaptation to toxic plants.



Percent infection by N. rileyi of H. virescens larvae exposed to fungus-treated plants for 24 h was greater when plants were toxic, and was greater for nonadapted larvae than toxin-adapted larvae. There were corresponding decreases in larval survival on toxic compared to nontoxic plants, and of nonadapted compared to adapted larvae. Interaction of effects of plant line and larval strain on survival was significant in the presence of fungus, but not in the absence of fungus, which indicates that the effect of toxic plants on the relative fitness of toxin-adapted and nonadapted larvae was mediated by fungus. As in the interaction with C. sonorensis, behavior of larvae on plants may explain differences in susceptibility to N. rileyi. Because nonadapted larvae moved more than toxin-adapted larvae on toxic plants, nonadapted larvae may have been more likely to encounter a lethal dose of conidia. In contrast with C. sonorensis, N. rileyi, which decreased the fitness of the nonadapted genotype relative to the adapted genotype, is expected to accelerate adaptation to toxic plants.}, number={2}, journal={ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA}, author={Johnson, MT and Gould, F and Kennedy, GG}, year={1997}, month={Feb}, pages={219–230} }
 @article{hruska_gould_1997, title={Fall armyworm (Lepidoptera: Noctuidae) and Diatraea lineolata (Lepidoptera: Pyralidae): Impact of larval population level and temporal occurrence on maize yield in Nicaragua}, volume={90}, ISSN={["0022-0493"]}, DOI={10.1093/jee/90.2.611}, abstractNote={Four experiments were conducted in Nicaragua over a 3-yr period to determine the effect of whorl-stage infestations of Spodoptera frugiperda (J. E. Smith) and Diatraea lineolata (Walker) on maize grain yields. The experiments separated the effects of period of infestation from level of infestation. Results from all experiments demonstrated that maize is more tolerant of lepidopteran infestation during early growth stages than at later stages. Infestation during mid-through late whorl caused yield losses of 15-73% when 55-100% of the plants were infested with S. frugiperda. D. lineolata infestations were highly correlated with S. frugiperda. D. lineolata infestations were highly correlated with S. frugiperda infestation. Economic injury levels ranged from 23 to 63% of the plants infested with S. frugiperda and D. lineolata over a range of potential yields, using mean yield reduction from the 4 experiments, and an average 75% insecticide effectiveness.}, number={2}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Hruska, AJ and Gould, F}, year={1997}, month={Apr}, pages={611–622} }
 @article{lu_kennedy_gould_1997, title={Genetic variation in larval survival and growth and response to selection by Colorado potato beetle (Coleoptera: Chrysomelidae) on tomato}, volume={26}, ISSN={["1938-2936"]}, DOI={10.1093/ee/26.1.67}, abstractNote={Leptinotarsa decemlineata (Say) originating from potato in Massachusetts (UM strain) differed from those originating from potato in New York (NY strain) in their ability to use tomato, Lycopersicon esculentum Miller, as a host. Larvae from the UM strain had higher survival and weighed more on tomato than larvae from the NY strain. Both strains responded to selection for adaptation to tomato. Larval survival to 4-d and the weight of 4-d-old larvae significantly increased in the NY strain after adults and larvae were maintained on tomato for 3 generations. The UM strain did not respond to selection during 4 generations; but 4-d-old larvae reared on tomato were significantly larger after 12 generations of selection than in the unselected control. In both strains, weights of larvae reared on tomato increased when selection on tomato occurred only during the larval stage. Reciprocal crosses between the selected and unselected strains provided no evidence for sex linkage or cytoplasmic inheritance of the differences in larval survival and larval weight on tomato. Similarly, there was no evidence that the food plant of the mother affected the survival of her offspring on either tomato or potato. However, there was evidence that the choice of food plant made by the mother during larval and adult stages affected the 4-d weight of her offspring on tomato; this effect was observed in the unselected NY strain, but not in a UM strain that had been selected in the larval stage on tomato for 8 generations. Increased adaptation to tomato was not associated with a decrease in adaptation to potato, as measured by weight and survival of 4-d-old larvae.}, number={1}, journal={ENVIRONMENTAL ENTOMOLOGY}, author={Lu, WH and Kennedy, GG and Gould, F}, year={1997}, month={Feb}, pages={67–75} }
 @article{heckel_gahan_gould_daly_trowell_1997, title={Genetics of Heliothis and Helicoverpa resistance to chemical insecticides and to Bacillus thuringiensis}, volume={51}, DOI={10.1002/(sici)1096-9063(199711)51:3<251::aid-ps629>3.3.co;2-e}, number={3}, journal={Pesticide Science}, author={Heckel, D. G. and Gahan, L. J. and Gould, Fred and Daly, J. C. and Trowell, S.}, year={1997}, pages={251–258} }
 @article{rigginbucci_gould_1997, title={Impact of intraplot mixtures of toxic and nontoxic plants on population dynamics of diamondback moth (Lepidoptera: Plutellidae) and its natural enemies}, volume={90}, ISSN={["0022-0493"]}, DOI={10.1093/jee/90.2.241}, abstractNote={Studies were conducted in 1993 and 1994 to investigate the effects of intraplot mixtures of toxic (with Bacillus thuringiensis Berliner) and nontoxic plants on population dynamics of diamondback moth, Plutella xylostella (L.), and its natural enemies. In 1993, diamondback moth densities in all plots (mixed and nonmixed) declined after generation 2, apparently because of poor plant quality. In 1994, mixed plots with 83.3% toxic and 16.7% nontoxic plants caused diamondback moth densities on nontoxic plants to decline after 2 generations, whereas population densities in plots of 100% nontoxic plants continued to rise. Diamondback moth, Plutella xylostella (L.), dynamics in plots with 50% toxic plants were intermediate compared with dynamics in the other treatment plots. Percentage of parasitism by the parasitoid Diadegmo insulare Cresson was not significantly different between mixed and nonmixed plots. Incidence of the 4 most abundant diamondback moth predators was not different in mixed and nonmixed plots, nor was there a difference in numbers of predators on toxic versus nontoxic plants. These data suggest that intrafield mixtures could serve to decrease density of a target pest such as the diamondback moth, while not adversely affecting natural enemies.}, number={2}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={RigginBucci, TM and Gould, F}, year={1997}, month={Apr}, pages={241–251} }
 @article{gould_anderson_jones_sumerford_heckel_lopez_micinski_leonard_laster_1997, title={Initial frequency of alleles for resistance to Bacillus thuringiensis toxins in field populations of Heliothis virescens}, volume={94}, ISSN={["0027-8424"]}, DOI={10.1073/pnas.94.8.3519}, abstractNote={The risk of rapid pest adaptation to an insecticide is highly dependent on the initial frequency of resistance alleles in field populations. Because we have lacked empirical estimates of these frequencies, population-genetic models of resistance evolution have relied on a wide range of theoretical estimates. The recent commercialization of genetically engineered cotton that constitutively produces an insecticidal protein derived from the biocontrol agent, Bacillus thuringiensis (Bt) has raised concern that we lack data needed to quantify the risk of insect pests such as Heliothis virescens rapidly adapting to this ecologically valuable class of toxins. By individually mating over 2,000 male H. virescens moths collected in four states to females of a Bt toxin-resistant laboratory strain, and screening F1 and F2 offspring for tolerance of the toxic protein, we were able to directly estimate the field frequency of alleles for resistance as 1.5 x 10(-3). This high initial frequency underscores the need for caution in deploying transgenic cotton to control insect pests. Our single-pair mating technique greatly increases the efficiency of detecting recessive resistance alleles. Because alleles that decrease target site sensitivity to Bt toxins and other insecticides are often recessive, this technique could be useful in estimating resistance allele frequencies in other insects exposed to transgenic insecticidal crops or conventional insecticides.}, number={8}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Gould, F and Anderson, A and Jones, A and Sumerford, D and Heckel, DG and Lopez, J and Micinski, S and Leonard, R and Laster, M}, year={1997}, month={Apr}, pages={3519–3523} }
 @inbook{gould_1997, title={Integrating pesticidal engineered crops into Mesoamerican agriculture}, ISBN={1885995415}, DOI={10.1016/s0261-2194(97)84561-9}, abstractNote={A major function of a subfamily of NLR (nucleotide-binding domain, leucine-rich repeat containing, or NOD-like receptor) proteins is in inflammasome activation, which has been implicated in a multitude of disease models and human diseases. This work will highlight key progress in understanding the mechanisms that activate the best-studied NLRs (NLRP3, NLRC4, NAIP, and NLRP1) and in uncovering inflammasome NLRs.}, booktitle={Transgenic plants : Bacillus thuringiensis in Mesoamerican agriculture}, publisher={Zamorano, Honduras : Libreri?a Zamorano}, author={Gould, F.}, editor={A. J. Hruska and Pavo?n, M. L.Editors}, year={1997}, pages={6} }
 @article{arpaia_gould_kennedy_1997, title={Potential impact of Coleomegilla maculata predation on adaptation of Leptinotarsa decemlineata to Bt-transgenic potatoes}, volume={82}, ISSN={["0013-8703"]}, DOI={10.1046/j.1570-7458.1997.00117.x}, abstractNote={The relationship between Leptinotarsa decemlineata Say egg density and Coleomegilla maculata DeGeer predatory behavior was investigated at different spatial scales (plant-to-plant and plot-to-plot). Both adult C. maculata location and daily egg consumption rates were monitored over time in greenhouse and field tests. Despite aggregation in areas of highest prey density by C. maculata, egg consumption was inversely related to egg mass density at the smallest and the largest spatial scales tested. The experimental data on predation rates in high and low density field treatments were included in a mathematical model to simulate impact of natural enemies on the rate of L. decemlineata adaptation to Bt-toxin-expressing transgenic potato plants when Bt-expressing plants are mixed at the plot-to-plot level with normal potato plants. Results showed that C. maculata predatory behavior could decrease the rate at which L. decemlineata adapted to Bt-toxins if plot-to-plot mixed-plantings were used.}, number={1}, journal={ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA}, author={Arpaia, S and Gould, F and Kennedy, G}, year={1997}, month={Jan}, pages={91–100} }
 @inbook{gould_1996, title={Deploying pesticidal engineered crops in developing countries}, ISBN={0851989306}, booktitle={Biotechnology and integrated pest management}, publisher={Oxon : CAB International}, author={Gould, F.}, year={1996}, pages={264} }
 @article{gould_kennedy_kopanic_1996, title={Environmental issues associated with enhancing the impact of biological control agents. A student debate}, volume={42}, DOI={10.1093/ae/42.3.160}, abstractNote={One major goal of graduate education is to familiarize students with the concepts, facts, and techniques that are essential to progress in a specific discipline. An additional goal should be to prepare students to use their newly acquired knowledge. One important challenge to scientists working in both basic and applied fields is to use incomplete and often conflicting sets of facts and theories in formulating public policies with broad impacts, or in prioritizing research programs at the level of the individual laboratory or at more general levels.}, number={3}, journal={American Entomologist (Lanham, Md.)}, author={Gould, F. and Kennedy, G. and Kopanic, R.}, year={1996}, pages={160} }
 @article{gould_anderson_reynolds_bumgarner_moar_1995, title={SELECTION AND GENETIC-ANALYSIS OF A HELIOTHIS-VIRESCENS (LEPIDOPTERA, NOCTUIDAE) STRAIN WITH HIGH-LEVELS OF RESISTANCE TO BACILLUS-THURINGIENSIS TOXINS}, volume={88}, ISSN={["0022-0493"]}, DOI={10.1093/jee/88.6.1545}, abstractNote={Heliothis virescens (F.), tobacco budworms eggs were collected from 3 adjacent counties in North Carolina. A laboratory strain (YDK) was established from these eggs using precautions to avoid loss of genetic diversity. A subset of this laboratory strain (YHD2) was selected on artificial diet containing the Bacillus thuringiensis (Berliner) toxin, CryIA(c). In the first 12 episodes of selection only moderate resistance (7- to 8-fold) was found. However, after 19 episodes of selection the strain had developed >500-fold resistance to the CryIA(c) toxin. Further selection lead to higher levels of resistance with the greatest resistance ratio recorded being 10,000-fold. The YHD2 strain was cross-resistant to CryIA(a), CryIA(b) and CryIF. We also found some resistance to CryIB, CryIC and CryIIA, but the level of resistance to these toxins was more moderate. Reciprocal genetic crosses between the resistant and control strains indicated that resistance to CryIA(c) and to CryIA(b) was partially recessive, but that the low level of resistance to CryIIA was more dominant. Progeny from backcrosses of F 1 larvae to the resistant parent were placed on artificial diet containing a concentration of CryIA(b) that had previously been found to slow the growth of F 1 larvae. When these larvae were weighed after 10 d, two clearly demarcated size classes were found in 1 :1 ratios as is expected in backcrosses when a single locus (or a set of tightly linked loci) is coding for a major component of a recessive trait. Adults that developed from the larger size class of larvae were mated and their offspring inherited the ability to grow well on CryIA(b). As expected from the single locus model, one quarter of the offspring from matings of the small backcross larvae grew well on CryIA(b). Results of this selection experiment indicate that the initial frequency of this resistance trait could be approximately 10 -3 , but field tests will be needed to confirm this rough estimate.}, number={6}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={GOULD, F and ANDERSON, A and REYNOLDS, A and BUMGARNER, L and MOAR, W}, year={1995}, month={Dec}, pages={1545–1559} }
 @article{gould_1994, title={POTENTIAL AND PROBLEMS WITH HIGH-DOSE STRATEGIES FOR PESTICIDAL ENGINEERED CROPS}, volume={4}, ISSN={["0958-3157"]}, DOI={10.1080/09583159409355357}, abstractNote={We lack an empirical basis on which to judge the expected durability of crops that express one or more insecticidal proteins and must therefore rely upon theoretical population genetic models in assessing how best to delay pest adaptation to these toxins. A number of studies using such models indicate that expression of toxins at very high levels could slow pest adaptation to a crawl if the ecology and genetics of the pest and cropping system fit specific assumptions. These assumptions relate to: (1) inheritance of resistance factors; (2) ecological costs of resistance factors; (3) behavioral response of larvae and adults to the toxins; (4) plant‐to‐plant movement of larvae; (5) adult dispersal and mating behavior; and (6) distribution of host plants that do and do not produce the toxin(s). This paper includes a discussion of whether the biology of insect pests of a number of cropping systems that are targets for toxin‐expressing plants fit assumptions that are conducive to slowing pest adaptation. Emphas...}, number={4}, journal={BIOCONTROL SCIENCE AND TECHNOLOGY}, author={GOULD, F}, year={1994}, pages={451–461} }
 @misc{gould_1991, title={ARTHROPOD BEHAVIOR AND THE EFFICACY OF PLANT PROTECTANTS}, volume={36}, ISSN={["1545-4487"]}, DOI={10.1146/annurev.en.36.010191.001513}, abstractNote={Analyse des effets des composes protecteurs des plantes sur le comportement des arthropodes. Evaluation des futurs comportements face aux nouveaux moyens de lutte}, journal={ANNUAL REVIEW OF ENTOMOLOGY}, author={GOULD, F}, year={1991}, pages={305–330} }
 @article{gould_anderson_1991, title={EFFECTS OF BACILLUS-THURINGIENSIS AND HD-73 DELTA-ENDOTOXIN ON GROWTH, BEHAVIOR, AND FITNESS OF SUSCEPTIBLE AND TOXIN-ADAPTED STRAINS OF HELIOTHIS-VIRESCENS (LEPIDOPTERA, NOCTUIDAE)}, volume={20}, ISSN={["1938-2936"]}, DOI={10.1093/ee/20.1.30}, abstractNote={A commercial formulation of Bacillus thuringiensis var. kurstaki Berliner (Dipel 2X) and purified HD-73 delta-endotoxin were evaluated for effects on the growth, behavior, and fitness of susceptible and toxin-adapted strains of Heliothis virescens (F.) by incorporation of the materials into artificial diets at varying concentrations. Neonate larvae were placed in experimental arenas where they could choose a diet containing toxin and a control diet, or were placed in arenas where the only diet available contained a toxin. The difference between the strains in growth and survival was much more pronounced when larvae could not choose to feed on the control diet. Both strains avoided moderate and high concentrations of the toxins. At the lowest concentration of HD-73, neither strain avoided the diet that contained the endotoxin. At the two lowest concentrations of Dipel 2X, only the susceptible strain avoided the diet containing Dipel. Data on growth rate, survival, and fecundity of the two strains reared on HD-73 delta-endotoxin were used to set parameters of a Single-locus genetic model to predict the rate at which H. virescens populations would adapt to B. thuringiensis var. kurstaki or its endotoxin when exposed to it in choice and no-choice situations. Results from the model generally predict much more rapid adaptation in no-choice situations.}, number={1}, journal={ENVIRONMENTAL ENTOMOLOGY}, author={GOULD, F and ANDERSON, A}, year={1991}, month={Feb}, pages={30–38} }
 @article{gould_kennedy_johnson_1991, title={EFFECTS OF NATURAL ENEMIES ON THE RATE OF HERBIVORE ADAPTATION TO RESISTANT HOST PLANTS}, volume={58}, ISSN={["1570-7458"]}, DOI={10.1111/j.1570-7458.1991.tb01445.x}, abstractNote={Abstract The potential of natural enemies to influence the rate of herbivore adaptation to resistance factors in plants is examined using conceptual and mathematical models. Results indicate that natural enemies could increase or decrease the rate of herbivore adaptation. The specific behavioral and physiological effects of a resistance factor on the herbivore, as well as the behavior of the natural enemy, and the population dynamics of the natural enemy/herbivore system are important in assessing the extent to which the natural enemies will affect the rate of herbivore adaptation to a resistance factor. Herbivore adaptation to partial resistance in a host-plant is generally expected to be slower than adaptation to high levels of resistance, even in the presence of natural enemies, if genetic variance is not limiting. Résumé Influence des ennemis naturels sur le taux d'adaptation d'herbivores à des plantes-hôtes résistantes Des modèles conceptuels et mathématiques ont servi à examiner l'influence du potentiel d'ennemis naturels sur le taux d'adaptation d'herbivores à des facteurs de résistance des plantes. Les résultats montrent que les ennemis naturels peuvent augmenter ou réduire le taux d'adaptation des herbivores. Les effets spécifiques (comportementaux et physiologiques) d'un facteur de résistance sur l'herbivore, aussi bien que le comportement de l'ennemi naturel et la dynamique de population du système ennemi naturel/herbivore permettent de déterminer le niveau de l'effet des ennemis naturels sur le taux d'adaptation de l'herbivore au facteur de résistance. Une adaptation de l'herbivore à une résistance partielle à une plante est généralement envisagée comme plus lente qu'une adaptation à des hauts niveaux de résistance, même en présence d'ennemis naturels, mais il peut y avoir des exceptions.}, number={1}, journal={ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA}, author={GOULD, F and KENNEDY, GG and JOHNSON, MT}, year={1991}, month={Jan}, pages={1–14} }
 @article{gould_1991, title={The evolutionary potential of crop pests}, volume={79}, number={6}, journal={American Scientist}, author={Gould, F.}, year={1991}, pages={496} }
 @inbook{gould_1990, title={Ecological genetics and integrated pest management}, ISBN={007052923X}, booktitle={Agroecology}, publisher={New York : McGraw Hill}, author={Gould, F.}, editor={C. R. Carroll, J. H. Vandermeer and Rosset, P.Editors}, year={1990}, pages={441} }
 @misc{gould_pour_villani_1987, title={Ecologically improved process of protecting certain crops from damage by soil-inhabiting insect pests and product produced thereby}, volume={4,676,985}, DOI={10.1016/0734-9750(87)90865-2}, number={1987 Jun. 30}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Gould, F. L. and Pour, D. C. and Villani, M. G.}, year={1987} }
 @article{gould_massey_1984, title={CUCURBITACINS AND PREDATION OF THE SPOTTED CUCUMBER BEETLE, DIABROTICA-UNDECIMPUNCTATA-HOWARDI}, volume={36}, ISSN={["0013-8703"]}, DOI={10.1111/j.1570-7458.1984.tb03439.x}, abstractNote={Abstract Two hypotheses about the relationship of diabroticina beetles and plants in the family Cucurbitaceae are tested: (1) evolution of sensory receptors for cucurbitacins by diabroticina beetles was in part due to the predator protection offered by ingestion of these compounds, and (2) commercial varieties of cucurbitacin-producing cucumber offer Diabrotica undecimpunctata howardi Barber chemical protection from some potential sources of natural control Spotted cucumber beetles fed either 'Marketmore 70′ cucumber which contains cucurbitacin-C or 'Marketmore 72′ which totally lacks cucurbitacin were presented to four species of vertebrate predators that commonly occur in the summer and/or winter habitats of D. u. howardi: Bufo americanus, B. fowleri, Peromyscus maniculatus, Colinus virginianus. None of the four species were significantly deterred from preying on beetles that had eaten Marketmore 70 cucumber. These results do not support either of the two hypotheses. The limitations of these negative results as evidence for refutation of the first hypothesis are discussed. RÉSUMÉ Les cucubitacines et la lutte biologique contre Diabrotica undecimpunctata howardi Barber Deux hypothèses concernant les relations entre les Diabroticina et les Cucurbitaceae ont été examinées: (1) l'évolution chez les Diabroticina des récepteurs pour les Cucurbitacines est due en partie à la protection contre les prédateurs apportée par la consommation de ces produits (2) les variétés modernes de concombres produisant de la cucurbitacine fournissent à D. undecimpunctata howardi Barber une protection chimique contre quelques sources potentielles de lutte biologique. Des D. undecimpunctata howardi, ayant consommé soit des concombres 'Marketmore 70′ contenant de la cucurbitacine C, soit des concombres 'Marketmore 72′ qui ont totalement perdu leur cucurbitacine, ont été présentés à quatre espèces de vertébrés prédateurs, qui s'observent fréquemment dans les habitats d'été ou d'hiver de D. undecimpunctata howardi soient Bufo americanus, B. fowleri, Peromyscus maniculatus, Colinus virginianus. Aucune de ces quatre espèces n'est significativement dissuadée d'attaquer les coléoptères qui on consommé les concombres 'Marketmore 70′. Ces résultats n'étayent aucune des deux hypothèses. La discussion porte sur les limites de ces résultats négatifs comme preuve de la réfutation de l'hypothèse 1.}, number={3}, journal={ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA}, author={GOULD, F and MASSEY, A}, year={1984}, pages={273–278} }
 @article{gould_1984, title={Mixed function oxidases and herbivore polyphagy: The devil's advocate position}, volume={9}, DOI={10.1111/j.1365-2311.1984.tb00695.x}, number={1}, journal={Ecological Entomology}, author={Gould, F.}, year={1984}, pages={29} }
 @article{gould_1984, title={Role of behavior in the evolution of insect adaptation to insecticides and resistant host plants}, volume={30}, DOI={10.1093/besa/30.4.34}, abstractNote={A two-locus genetic model was developed for examining factors influencing adaptation by pests to compounds or plants that have both insecticidal and repellent properties. The model allows genetic variation in the pest population for physiological adaptation and behavioral avoidance. The biological assumptions of the model are appropriate for mobile pests such as Heliothis spp. The results of the model suggest that: (1) in many situations, physiological adaptation will evolve more slowly when insecticide formulations with high repellency are used instead of nonrepellent formulations; (2) Crop cultivars with both “antibiotic” and “nonpreference” types of resistance should often be less prone to counter-adaptation by oligophagous and polyphagous pests than cultivars exhibiting only antibiotic resistance; (3) It is reasonable to expect some insect populations to evolve behavioral avoidance of antibiotic crop cultivars and insecticides which were originally not repellent to them; (4) Pest mobility and the spatial patterns of insecticide/repellent use can influence the direction and rate of evolutionary change in the pest. Development of insecticide formulations containing noninsecticidal compounds with repellent properties could lower the rate of pest physiological adaptation to an insecticide. Use of such formulations may, in some cases, induce higher pest damage to untreated crops thus raising problems for producers and regulatory agencies. In special cases, it may be possible to influence the development of resistance by pest or natural enemy species by mass release of strains with appropriate behavioral and physiological characteristics.}, number={4}, journal={Bulletin of the Entomological Society of America}, author={Gould, F.}, year={1984}, pages={34} }
 @article{gould_holtzman_rabb_smith_1980, title={GENETIC-VARIATION IN PREDATORY AND CANNIBALISTIC TENDENCIES OF HELIOTHIS-VIRESCENS (LEPIDOPTERA, NOCTUIDAE) STRAINS}, volume={73}, ISSN={["0013-8746"]}, DOI={10.1093/aesa/73.3.243}, abstractNote={When raised in the laboratory, Heliothis virescens strains differed in their propensity to cannibalize other H. virescens larvae. Propensity to cannibalize was correlated with rate of predation on Spodoptera exigua larvae and ability to compete with aggressive H. zea larvae. Implications of these findings for pest management are discussed.}, number={3}, journal={ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA}, author={GOULD, F and HOLTZMAN, G and RABB, RL and SMITH, M}, year={1980}, pages={243–250} }
 @article{gould_hodgson_1980, title={MIXED-FUNCTION OXIDASE AND GLUTATHIONE TRANSFERASE-ACTIVITY IN LAST INSTAR HELIOTHIS-VIRESCENS LARVAE}, volume={13}, ISSN={["0048-3575"]}, DOI={10.1016/0048-3575(80)90080-2}, abstractNote={Abstract Methyl parathion-resistant and -susceptible strains of Heliothis virescens were assayed for mixed function oxidase and glutathione transferase activity at four time periods within the last instar. No significant differences were found between the mixed function oxidase or glutathione transferase activities of the resistant and susceptible strains. However, significant differences did appear among time periods within the last instar. Larvae assayed during the postfeeding time period (60–80 hr) had the highest mixed function oxidase activity, which was 28 times that of last instar larvae assayed during the first time period (0–19 hr). Glutathione transferase activity appeared to be highest during the 20- to 39-hr and 40- to 59-hr time periods, but the differences among time periods were small. The importance of these findings to studies of insecticide resistance and plant herbivore interactions is discussed.}, number={1}, journal={PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY}, author={GOULD, F and HODGSON, E}, year={1980}, pages={34–40} }