@article{silverman_taylor_2024, title={Prey detection by a stepwise visual template matching mechanism}, volume={11}, ISSN={["2054-5703"]}, url={https://doi.org/10.1098/rsos.241042}, DOI={10.1098/rsos.241042}, number={11}, journal={ROYAL SOCIETY OPEN SCIENCE}, author={Silverman, Jules and Taylor, Brad W.}, year={2024}, month={Nov} }
 @article{mcpherson_wada-katsumata_hatano_silverman_schal_2022, title={Nutritional condition affects tergal gland secretion and courtship success of male cockroaches}, volume={17}, ISSN={["1932-6203"]}, url={https://doi.org/10.1371/journal.pone.0271344}, DOI={10.1371/journal.pone.0271344}, abstractNote={An integral part of the courtship sequence of the German cockroach (Blattella germanica) involves the male raising his wings to expose tergal glands on his dorsum. When a female cockroach feeds on the secretion of these glands, she is optimally positioned for mating. Core chemical components have been identified, but the effect of male diet on the quality of the tergal gland secretion remains unexplored. After validating the pivotal role of tergal feeding in mating, we starved or fed reproductively mature males for one week. We then paired each male with a sexually receptive female and observed their interactions through an infrared-sensitive camera. While starvation had no effect on male courtship behavior, it did influence the duration of female tergal feeding and mating outcomes. Females fed longer on the gland secretion of fed males, and fed males experienced greater mating success than starved males (73.9% vs. 48.3%, respectively). These results suggest that the quality of the tergal gland secretions, and by association mating success, are dependent on the nutritional condition of the male.}, number={8}, journal={PLOS ONE}, author={McPherson, Samantha and Wada-Katsumata, Ayako and Hatano, Eduardo and Silverman, Jules and Schal, Coby}, editor={Borges, Renee M.Editor}, year={2022} }
 @article{wada-katsumata_hatano_mcpherson_silverman_schal_2022, title={Rapid evolution of an adaptive taste polymorphism disrupts courtship behavior}, volume={5}, ISSN={["2399-3642"]}, url={https://doi.org/10.1038/s42003-022-03415-8}, DOI={10.1038/s42003-022-03415-8}, abstractNote={AbstractThe evolution of adaptive behavior often requires changes in sensory systems. However, rapid adaptive changes in sensory traits can adversely affect other fitness-related behaviors. In the German cockroach, a gustatory polymorphism, ‘glucose-aversion (GA)’, supports greater survivorship under selection with glucose-containing insecticide baits and promotes the evolution of behavioral resistance. Yet, sugars are prominent components of the male’s nuptial gift and play an essential role in courtship. Behavioral and chemical analyses revealed that the saliva of GA females rapidly degrades nuptial gift sugars into glucose, and the inversion of a tasty nuptial gift to an aversive stimulus often causes GA females to reject courting males. Thus, the rapid emergence of an adaptive change in the gustatory system supports foraging, but it interferes with courtship. The trade-off between natural and sexual selection under human-imposed selection can lead to directional selection on courtship behavior that favors the GA genotype.}, number={1}, journal={COMMUNICATIONS BIOLOGY}, author={Wada-Katsumata, Ayako and Hatano, Eduardo and McPherson, Samantha and Silverman, Jules and Schal, Coby}, year={2022}, month={May} }
 @article{mcpherson_wada-katsumata_hatano_silverman_schal_2021, title={Comparison of Diet Preferences of Laboratory-Reared and Apartment-Collected German Cockroaches}, volume={114}, ISSN={["1938-291X"]}, url={https://doi.org/10.1093/jee/toab139}, DOI={10.1093/jee/toab139}, abstractNote={AbstractThe German cockroach, Blattella germanica (L.) (Blattodea: Ectobiidae), is a common pest of human-built structures worldwide. German cockroaches are generalist omnivores able to survive on a wide variety of foods. A number of studies have concluded that laboratory-reared B. germanica self-select diets with an approximate 1P:3C (protein-to-carbohydrate) ratio. We predicted that field-collected insects would exhibit more variable dietary preferences, related to the wide-ranging quality, quantity, and patchiness of foods available to them. We compared diet self-selection of B. germanica within apartments and in the laboratory by offering them a choice of two complementary diets with 1P:1C and 1P:11C ratios. We observed high variation in the population-level self-selection of these diets among individual apartment sites as well as among various life stages tested in laboratory-based assays. Significant differences between populations in various apartments as well as between populations maintained in the laboratory suggested that factors beyond temporary food scarcity influence diet choice. Nevertheless, we found significant correlations between the amounts of diets ingested by cockroaches in apartments and cockroaches from the same populations assayed in the laboratory, as well as between males, females, and nymphs from these populations. These findings suggest that females, males, and nymphs within apartments adapt to the local conditions and convergently prefer similar amounts of food of similar dietary protein content.}, number={5}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, publisher={Oxford University Press (OUP)}, author={McPherson, Samantha and Wada-Katsumata, Ayako and Hatano, Eduardo and Silverman, Jules and Schal, Coby}, editor={Appel, ArthurEditor}, year={2021}, month={Oct}, pages={2189–2197} }
 @article{wada-katsumata_robertson_silverman_schal_2018, title={Changes in the Peripheral Chemosensory System Drive Adaptive Shifts in Food Preferences in Insects}, volume={12}, ISSN={1662-5102}, url={http://dx.doi.org/10.3389/fncel.2018.00281}, DOI={10.3389/fncel.2018.00281}, abstractNote={A key challenge in understanding the evolution of animal behaviors is to identify cellular and molecular mechanisms that underlie the evolution of adaptive traits and behaviors in polymorphic populations under local selection pressures. Despite recent advances in fish, mice, and insects, there are still only a few compelling examples of major genes and cellular mechanisms associated with complex behavioral changes. Shifts in food or host preferences in insects, accompanied by changes in the peripheral chemosensory system, offer some of the best examples of adaptive behavioral evolution. A remarkable example is the German cockroach, Blattella germanica, a major indoor pest with a highly diverse omnivorous diet. Strong and persistent selection pressure with toxic-baits has induced rapid evolution of behavioral resistance in multiple cockroach populations. While typical cockroaches detect and accept the sugar glucose as a feeding-stimulant, behaviorally resistant cockroaches avoid eating glucose-containing toxic baits by sensing glucose as a deterrent. We review the peripheral gustatory neural mechanisms of glucose-aversion and discuss how the rapid emergence of taste polymorphisms can impede pest control efforts and affect foraging and mate-choice in adapted cockroach populations.}, journal={Frontiers in Cellular Neuroscience}, publisher={Frontiers Media SA}, author={Wada-Katsumata, Ayako and Robertson, Hugh M. and Silverman, Jules and Schal, Coby}, year={2018}, month={Aug} }
 @article{jensen_silverman_2018, title={Frequently mated males have higher protein preference in German cockroaches}, volume={29}, ISSN={["1465-7279"]}, DOI={10.1093/beheco/ary104}, abstractNote={Protein is an abundant nutrient in sperm, and males therefore expend protein every time they mate. In addition, many males provide the female with a nitrogen-rich nuptial gift during mating, which often increases female fertility by supplementing her pool of limiting nutrients. However, it is unknown whether males compensate for the nitrogen cost of mating by increasing their preference for protein, which would facilitate the production of new sperm and nuptial gift material. Using artificial diets, we investigated whether male German cockroaches (Blattella germanica) would compensate for nitrogen expenses of mating by increasing protein preference when given the opportunity to self-select their diet from complementary foods differing only in protein and carbohydrate content. We distributed adult males across 4 mating regimes differing in the frequency of mating opportunities with receptive females and measured protein and carbohydrate consumption as well as reproductive output over the lifespan of each male. Receptive females were either never available (no mating opportunity), or they were available overnight at a frequency of each 28 days (rare mating opportunities), each 14 days (occasional mating opportunities), or each 7 days (frequent mating opportunities). Males selected highly carbohydrate-biased diets. However, males that mated more frequently had higher consumption and reproduction and self-selected higher lifetime protein to carbohydrate ratios. Our study demonstrates that male German cockroaches actively select a more protein-biased diet that compensates for their nutritional requirements following mating. The study shows that male mating significantly affects foraging decisions for specific nutrients to compensate for the expenses of mating.}, number={6}, journal={BEHAVIORAL ECOLOGY}, author={Jensen, Kim and Silverman, Jules}, year={2018}, pages={1453–1461} }
 @article{silverman_buczkowski_2016, title={Behaviours mediating ant invasions}, journal={Biological Invasions and Animal Behaviour}, author={Silverman, J. and Buczkowski, G.}, year={2016}, pages={221–244} }
 @article{ko_schal_silverman_2016, title={Diet quality affects bait performance in German cockroaches (Dictyoptera: Blattellidae)}, volume={72}, ISSN={1526-498X}, url={http://dx.doi.org/10.1002/ps.4295}, DOI={10.1002/ps.4295}, abstractNote={AbstractBACKGROUNDBait formulations are widely used to control German cockroach (Blattella germanica) populations. To perform optimally, these formulations must compete favorably with non‐toxic alternative foods present within the insect's habitat. We hypothesized that the nutritional history of cockroaches and their acceptance or avoidance of glucose would affect their food preference and thus bait efficacy. To test this hypothesis, we conducted a controlled laboratory experiment, first providing glucose‐accepting and glucose‐averse cockroaches nutritionally defined diets and then offering them identical diets containing the insecticide hydramethylnon as a bait proxy to evaluate the effect of diets of differing macronutrient composition on bait performance.RESULTSThe interaction between diet composition and bait composition affected the survival of adult males as well as first‐instar nymphs exposed to excretions produced by these males. Survival analyses indicated different responses of glucose‐averse and glucose‐accepting insects, but generally any combination of diet and bait that resulted in high diet intake and low bait intake reduced secondary kill.CONCLUSIONSThis study represents a comprehensive examination of the effect of alternative foods on bait efficacy. We suggest that disparities between the nutritional quality of baits and the foods that are naturally available could profoundly impact the management of German cockroach infestations. © 2016 Society of Chemical Industry}, number={10}, journal={Pest Management Science}, publisher={Wiley}, author={Ko, Alexander E and Schal, Coby and Silverman, Jules}, year={2016}, month={May}, pages={1826–1836} }
 @article{ko_jensen_schal_silverman_2016, title={Effects of foraging distance on macronutrient balancing and performance in the German cockroach Blattella germanica}, volume={220}, ISSN={0022-0949 1477-9145}, url={http://dx.doi.org/10.1242/jeb.146829}, DOI={10.1242/jeb.146829}, abstractNote={The German cockroach (Blattella germanica L.) is an excellent model omnivore for studying the effect of foraging effort on nutrient balancing behavior and physiology, and its consequences for performance. We investigated the effect of foraging distance on individual German cockroaches by providing two foods differing in protein-to-carbohydrate ratio at opposite ends of long containers or adjacent to each other in short containers. Each food was nutritionally imbalanced, but the two foods were nutritionally complementary, allowing optimal foraging by selective feeding from both foods. We measured nutrient-specific consumption in fifth instar nymphs and newly eclosed females foraging at the two distances, hypothesizing that individuals foraging over longer distance would select more carbohydrate-biased diets to compensate for the energetic cost of locomotion. We then determined dry mass growth and lipid accumulation in the nymphs as well as mass gain and the length of basal oocytes in the adult females as an estimate of sexual maturation. Nymphs foraging over longer distance accumulated less lipid relative to total dry mass growth, but contrary to our predictions their protein intake was higher and they accumulated more structural mass. In concordance, adult females foraging over longer distance gained more body mass and matured their oocytes faster. Our results show a positive effect of foraging distance on fitness-related parameters at two life stages, in both cases involving increased consumption of specific nutrients corresponding to requirements at the respective life stage.}, number={2}, journal={The Journal of Experimental Biology}, publisher={The Company of Biologists}, author={Ko, Alexander E. and Jensen, Kim and Schal, Coby and Silverman, Jules}, year={2016}, month={Nov}, pages={304–311} }
 @article{jensen_ko_schal_silverman_2016, title={Insecticide resistance and nutrition interactively shape life-history parameters in German cockroaches}, volume={6}, ISSN={2045-2322}, url={http://dx.doi.org/10.1038/srep28731}, DOI={10.1038/srep28731}, abstractNote={AbstractFitness-related costs of evolving insecticide resistance have been reported in a number of insect species, but the interplay between evolutionary adaptation to insecticide pressure and variable environmental conditions has received little attention. We provisioned nymphs from three German cockroach (Blattella germanica L.) populations, which differed in insecticide resistance, with either nutritionally rich or poor (diluted) diet throughout their development. One population was an insecticide-susceptible laboratory strain; the other two populations originated from a field-collected indoxacarb-resistant population, which upon collection was maintained either with or without further selection with indoxacarb. We then measured development time, survival to the adult stage, adult body size, and results of a challenge with indoxacarb. Our results show that indoxacarb resistance and poor nutritional condition increased development time and lowered adult body size, with reinforcing interactions. We also found lower survival to the adult stage in the indoxacarb-selected population, which was exacerbated by poor nutrition. In addition, nutrition imparted a highly significant effect on indoxacarb susceptibility. This study exemplifies how poor nutritional condition can aggravate the life-history costs of resistance and elevate the detrimental effects of insecticide exposure, demonstrating how environmental conditions and resistance may interactively impact individual fitness and insecticide efficacy.}, number={1}, journal={Scientific Reports}, publisher={Springer Science and Business Media LLC}, author={Jensen, Kim and Ko, Alexander E. and Schal, Coby and Silverman, Jules}, year={2016}, month={Jun} }
 @article{jensen_schal_silverman_2015, title={Adaptive contraction of diet breadth affects sexual maturation and specific nutrient consumption in an extreme generalist omnivore}, volume={28}, ISSN={1010-061X}, url={http://dx.doi.org/10.1111/jeb.12617}, DOI={10.1111/jeb.12617}, abstractNote={AbstractAnimals balance their intake of specific nutrients, but little is known about how they do so when foraging in an environment with toxic resources and whether toxic foods promote adaptations that affect life history traits. In German cockroach (Blattella germanica) populations, glucose aversion has evolved in response to glucose‐containing insecticidal baits. We restricted newly eclosed glucose‐averse (GA) and wild‐type (WT) female cockroaches to nutritionally defined diets varying in protein‐to‐carbohydrate (P : C) ratio (3 : 1, 1 : 1, or 1 : 3) or gave them free choice of the 3 : 1 and 1 : 3 diets, with either glucose or fructose as the sole carbohydrate source. We measured consumption of each diet over 6 days and then dissected the females to measure the length of basal oocytes in their ovaries. Our results showed significantly lower consumption by GA compared to WT cockroaches when restricted to glucose‐containing diets, but also lower fructose intake by GA compared to WT cockroaches when restricted to high fructose diets or given choice of fructose‐containing diets. Protein intake was regulated tightly regardless of carbohydrate intake, except by GA cockroaches restricted to glucose‐containing diets. Oocyte growth was completely suppressed in GA females restricted to glucose‐containing diets, but also significantly slower in GA than in WT females restricted to fructose‐containing diets. Our findings suggest that GA cockroaches have adapted to reduced diet breadth through endocrine adjustments which reduce requirements for energetic fuels. Our study illustrates how an evolutionary change in the chemosensory system may affect the evolution of other traits that govern animal life histories.}, number={4}, journal={Journal of Evolutionary Biology}, publisher={Wiley}, author={Jensen, K. and Schal, C. and Silverman, J.}, year={2015}, month={Mar}, pages={906–916} }
 @article{ko_bieman_schal_silverman_2016, title={Insecticide resistance and diminished secondary kill performance of bait formulations against German cockroaches (Dictyoptera: Blattellidae)}, volume={72}, ISSN={1526-498X}, url={http://dx.doi.org/10.1002/ps.4211}, DOI={10.1002/ps.4211}, abstractNote={AbstractBACKGROUNDBait formulations are considered to be the most effective method for reducing German cockroach (Blattella germanica) infestations. An important property of some bait formulations is secondary kill, whereby active ingredient (AI) is translocated in insect‐produced residues throughout the cockroach population, especially affecting relatively sedentary early‐instar nymphs.RESULTSB. germanica was collected from a location where baits containing hydramethylnon, fipronil or indoxacarb had become ineffective, and these AIs were topically applied to adult males. Results revealed the first evidence for hydramethylnon resistance, moderate resistance to fipronil and extremely high resistance to indoxacarb. Insecticide residues excreted by field‐collected males that had ingested commercial baits effectively killed nymphs of an insecticide‐susceptible laboratory strain of B. germanica but failed to kill most nymphs of the field‐collected strain.CONCLUSIONSWe report three novel findings: (1) the first evidence for hydramethylnon resistance in any insect; (2) extremely high levels of indoxacarb resistance in a field population; (3) reduced secondary mortality in an insecticide‐resistant field‐collected strain of B. germanica. We suggest that, while secondary mortality is considered to be advantageous in cockroach interventions, the ingestion of sublethal doses of AI by nymphs may select for high insecticide resistance by increasing the frequency of AI resistance alleles within the population. © 2015 Society of Chemical Industry}, number={9}, journal={Pest Management Science}, publisher={Wiley}, author={Ko, Alexander E and Bieman, Donald N and Schal, Coby and Silverman, Jules}, year={2016}, month={Jan}, pages={1778–1784} }
 @article{shik_kay_silverman_2014, title={Aphid honeydew provides a nutritionally balanced resource for incipient Argentine ant mutualists}, volume={95}, ISSN={["1095-8282"]}, DOI={10.1016/j.anbehav.2014.06.008}, abstractNote={Food-for-protection mutualisms can provide resources that subsidize ecological dominance, although their stability often depends on the nutritional match between the traded food and traits to which it is allocated. A well-studied food-for-protection mutualism is the protection by Argentine ants, Linepithema humile, of hemipteran mutualists in return for honeydew, which is generally assumed to be a nutritionally imbalanced food, high in carbohydrates and low in protein. We tested an alternative hypothesis, that the nutritional value of honeydew depends on the composition of life history traits related to survival (worker maintenance) and colony growth (brood production). Using a factorial design, we manipulated ant colony access to aphids, baseline levels of nutritional deprivation, and, by adding or subtracting queens, the ability to invest in growth. We found that aphid access primarily benefited colonies on high-protein, low-carbohydrate diets, suggesting colony nutritional state influences the value of aphid associations. Unexpectedly, we found that worker survival and brood production were positively correlated across treatments, and both decreased with the ants' percentage of nitrogen mass, a proxy for body protein. Moreover, the workers' percentage of fat mass was generally lower in brood-producing colonies, particularly in high-protein treatments, suggesting strong competition among investments for limited carbohydrates. These results suggest that carbohydrate access generally constrains Argentine ant life history and clarifies the links between the nutritional composition of food rewards and the stability of ecologically important mutualisms.}, journal={ANIMAL BEHAVIOUR}, author={Shik, Jonathan Z. and Kay, Adam D. and Silverman, Jules}, year={2014}, month={Sep}, pages={33–39} }
 @article{shik_schal_silverman_2014, title={Diet specialization in an extreme omnivore: nutritional regulation in glucose-averse German cockroaches}, volume={27}, ISSN={1010-061X}, url={http://dx.doi.org/10.1111/jeb.12458}, DOI={10.1111/jeb.12458}, abstractNote={AbstractOrganisms have diverse adaptations for balancing dietary nutrients, but often face trade‐offs between ingesting nutrients and toxins in food. While extremely omnivorous cockroaches would seem excluded from such dietary trade‐offs, German cockroaches (Blattella germanica) in multiple populations have rapidly evolved a unique dietary specialization – an aversion to glucose, the phagostimulant in toxic baits used for pest control. We used factorial feeding experiments within the geometric framework to test whether glucose‐averse (GA) cockroaches with limited access to this critical metabolic fuel have compensatory behavioural and physiological strategies for meeting nutritional requirements. GA cockroaches had severely constrained intake, fat and N mass, and performance on glucose‐based diets relative to wild‐type (WT) cockroaches and did not appear to exhibit digestive strategies for retaining undereaten nutrients. However, a GA × WT ‘hybrid’ had lower glucose aversion than GA and greater access to macronutrients within glucose‐based diets – while still having lower intake and survival than WT. Given these intermediate foraging constraints, hybrids may be a reservoir for this maladaptive trait in the absence of positive selection and may account for the rapid evolution of this trait following bait application.}, number={10}, journal={Journal of Evolutionary Biology}, publisher={Wiley}, author={Shik, J. Z. and Schal, C. and Silverman, J.}, year={2014}, month={Jul}, pages={2096–2105} }
 @article{wada-katsumata_silverman_schal_2013, title={Changes in Taste Neurons Support the Emergence of an Adaptive Behavior in Cockroaches}, volume={340}, ISSN={0036-8075 1095-9203}, url={http://dx.doi.org/10.1126/science.1234854}, DOI={10.1126/science.1234854}, abstractNote={Sugar Aversion
          
            Several populations of the German cockroach have become averse to the glucose used as bait in toxic traps, which has severely reduced the traps' effectiveness.
            
              Wada-Katsumata
              et al.
            
            (p.
            972
            ) show that this aversion is a result of changes in the peripheral gustatory system, whereby glucose, as well as “sweet” receptors, stimulated an aversive bitter compound receptor.
          }, number={6135}, journal={Science}, publisher={American Association for the Advancement of Science (AAAS)}, author={Wada-Katsumata, A. and Silverman, J. and Schal, C.}, year={2013}, month={May}, pages={972–975} }
 @article{bednar_shik_silverman_2013, title={Prey handling performance facilitates competitive dominance of an invasive over native keystone ant}, volume={24}, ISSN={["1465-7279"]}, DOI={10.1093/beheco/art069}, abstractNote={Studies of species coexistence in ant communities often suggest that competitive interactions are mediated by behavioral trade-offs between resource discovery and dominance. However, these studies have always measured foraging at artificial, static baits that omit traits of living prey items and potential coevolutionary predator–prey relationships. In a series of lab experiments, we compare the ability of ants to harvest live termites (Reticulitermes virginicus) in nests varying in defensive ability. Moreover, we compare foraging performance of 2 co-occurring ant species—the North American native Aphaenogaster rudis and the invasive Pachycondyla chinensis—differing in their evolutionary experience hunting R. virginicus. Our results show how the invasive P. chinensis may displace the native keystone A. rudis by directly killing A. rudis workers and reducing termite prey available for A. rudis. Specifically, P. chinensis is more sensitive to novel termite prey than the native A. rudis and then destroys termite colonies—even if they are highly defended by soldiers or nest architecture. Our results further show how whole colony behavioral dominance by P. chinensis is mediated by behavioral interactions among individual workers. More generally, our experimental approach using live prey to study interspecific competition can integrate evolutionary dynamics into studies of proximate behavioral factors governing species coexistence.}, number={6}, journal={BEHAVIORAL ECOLOGY}, author={Bednar, David M. and Shik, Jonathan Z. and Silverman, Jules}, year={2013}, pages={1312–1319} }
 @article{rice_silverman_2013, title={Propagule Pressure and Climate Contribute to the Displacement of Linepithema humile by Pachycondyla chinensis}, volume={8}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0056281}, abstractNote={Identifying mechanisms governing the establishment and spread of invasive species is a fundamental challenge in invasion biology. Because species invasions are frequently observed only after the species presents an environmental threat, research identifying the contributing agents to dispersal and subsequent spread are confined to retrograde observations. Here, we use a combination of seasonal surveys and experimental approaches to test the relative importance of behavioral and abiotic factors in determining the local co-occurrence of two invasive ant species, the established Argentine ant (Linepithema humile Mayr) and the newly invasive Asian needle ant (Pachycondyla chinensis Emery). We show that the broader climatic envelope of P. chinensis enables it to establish earlier in the year than L. humile. We also demonstrate that increased P. chinensis propagule pressure during periods of L. humile scarcity contributes to successful P. chinensis early season establishment. Furthermore, we show that, although L. humile is the numerically superior and behaviorally dominant species at baits, P. chinensis is currently displacing L. humile across the invaded landscape. By identifying the features promoting the displacement of one invasive ant by another we can better understand both early determinants in the invasion process and factors limiting colony expansion and survival.}, number={2}, journal={PLOS ONE}, author={Rice, Eleanor Spicer and Silverman, Jules}, year={2013}, month={Feb} }
 @article{rice_silverman_2013, title={Submissive behaviour and habituation facilitate entry into habitat occupied by an invasive ant}, volume={86}, ISSN={["0003-3472"]}, DOI={10.1016/j.anbehav.2013.06.006}, abstractNote={An essential challenge in invasion ecology is discerning the role that behavioural adaptations play in competition among species. When evaluating the impacts of invasive species, the mechanisms underlying coexistence among organisms and the displacement of organisms within a community mosaic are often ignored, yet these interactions are necessary for fully understanding these impacts. Here, we examine behavioural mechanisms underlying the coexistence and subsequent displacement of an established global invader, the Argentine ant, Linepithema humile Mayr, by the newly invasive Asian needle ant, Pachycondyla chinensis Emery. In individual and group assays, we show that the numerically and behaviourally dominant Argentine ant is less aggressive towards P. chinensis workers from adjacent versus distant nests. Moreover, we show that P. chinensis displays submissive behaviour through recurrent contact with L. humile, which may contribute to the reported displacement of L. humile in the field. Understanding the factors that drive the coexistence of these two ants may help explain how small populations of a behaviourally submissive exotic species become established.}, number={3}, journal={ANIMAL BEHAVIOUR}, author={Rice, Eleanor Spicer and Silverman, Jules}, year={2013}, month={Sep}, pages={497–506} }
 @article{rice_shik_silverman_2012, title={Effect of Scattered and Discrete Hydramethylnon Bait Placement on the Asian Needle Ant}, volume={105}, ISSN={["1938-291X"]}, DOI={10.1603/ec12207}, abstractNote={ABSTRACT 
 The Asian needle ant (Pachycondyla chinensis Emery) is invading natural and disturbed habitats across the eastern United States. While recent studies document the impact of P. chinensis on native ecosystems and human health, effective control measures remain unknown. Thus, we evaluated the field performance of a hydramethylnon granular bait, Maxforce Complete Granular Insect Bait, dispersed in clumps or scattered against P. chinensis. We also measured the effect of this bait on P. chinensis outside of the treatment zone. Surprisingly, unlike reports for other ant species, we achieved nearly complete P. chinensis population reductions 1 d after treatments were applied. Significant ant reductions were achieved until the end of our study at 28 d. No difference was recorded between clumped and scattered application methods. We found no overall difference in ant reductions from the edge out to 5 m beyond the treatment zone. Other local ant species appeared to be unaffected by the bait and foraging activity increased slightly after P. chinensis removal from treated areas. We suggest that Maxforce Complete Granular Insect Bait can be effective in an Asian needle ant treatment program.}, number={5}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Rice, Eleanor Spicer and Shik, Jonathan Z. and Silverman, Jules}, year={2012}, month={Oct}, pages={1751–1757} }
 @article{vasquez_vargo_silverman_2012, title={Fusion Between Southeastern United States Argentine Ant Colonies and Its Effect on Colony Size and Productivity}, volume={105}, ISSN={["1938-2901"]}, DOI={10.1603/an11114}, abstractNote={Abstract
               The ecological success of invasive ants has been linked to their ability to form expansive supercolonies. In the Argentine ant, Linepithema humile (Mayr), increased productivity and competitive ability of introduced supercolonies in several places, e.g., California and southern Europe, has been linked to high population densities that could have been attained via fusion of nonaggressive and genetically similar nests. Recently, we have found that introduced L. humile colonies in the southeastern United States, which have higher levels of intraspecific aggression and genetic diversity than those in California and southern Europe, sometimes also fuse; yet it is unclear what the longer term consequences of such colony fusion might be. In this study, we examined whether fusion of these southeastern United States L. humile colonies results in larger colonies by recording colony size and productivity in pairs that fused and in pairs that did not fuse. After 6 mo, colonies that fused produced 47% more workers and had twice as many queens as colony pairs that did not fuse. Also, fused colonies had an overall per capita colony productivity (number of brood and workers produced per queen and per worker) comparable to that of nonfused pairs and unpaired controls. Furthermore, all queens contributed to worker pupae production in fused colonies. Thus, fusion of initially aggressive southeastern United States L. humile colonies results in colonies with higher worker number without decreasing per capita productivity. Moreover, offspring contribution by all queens in fused colonies may alter colony genotypic composition resulting in reduced intraspecific aggression that in turn promotes further fusion. This process may be relevant to the establishment of incipient colonies in areas where multiple introductions have occurred.}, number={2}, journal={ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA}, author={Vasquez, Gissella M. and Vargo, Edward L. and Silverman, Jules}, year={2012}, month={Mar}, pages={268–274} }
 @article{shik_silverman_2013, title={Towards a nutritional ecology of invasive establishment: aphid mutualists provide better fuel for incipient Argentine ant colonies than insect prey}, volume={15}, ISSN={["1573-1464"]}, DOI={10.1007/s10530-012-0330-x}, number={4}, journal={BIOLOGICAL INVASIONS}, author={Shik, Jonathan Z. and Silverman, Jules}, year={2013}, month={Apr}, pages={829–836} }
 @article{wada-katsumata_silverman_schal_2011, title={Differential Inputs from Chemosensory Appendages Mediate Feeding Responses to Glucose in Wild-Type and Glucose-Averse German Cockroaches, Blattella germanica}, volume={36}, ISSN={1464-3553 0379-864X}, url={http://dx.doi.org/10.1093/chemse/bjr023}, DOI={10.1093/chemse/bjr023}, abstractNote={Glucose is a universal phagostimulant in many animal species, including the cockroach Blattella germanica. However, some natural populations of B. germanica have been found that are behaviorally deterred from eating glucose. In dose-response studies, glucose was a powerful phagostimulant for wild-type cockroaches, but it strongly deterred feeding in a glucose-averse strain. Both strains, however, exhibited identical dose-response curves to other phagostimulants and deterrents. As a lead to electrophysiological and molecular genetics studies to investigate the mechanisms that underlie glucose-aversion, we used 2 assay paradigms to delineate which chemosensory appendages on the head contribute to the reception of various phagostimulatory and deterrent chemicals. Both simultaneous dual stimulation of the antenna and mouthparts of the insects and 2-choice preference tests in surgically manipulated insects showed that the glucose-averse behavior could be elicited through the gustatory systems of the antennae and mouthparts. The paraglossae alone were sufficient for maximum sensitivity to both phagostimulants and deterrents, including glucose as a deterrent in the glucose-averse strain. In addition to the paraglossae, the labial palps were more important than the maxillary palps in the reception of deterrents (caffeine in both strains and glucose in the glucose-averse strain). The maxillary palps, on the other hand, played a more important role in the reception of phagostimulants (fructose in both strains and glucose in the wild-type strain). Our results suggest that distinct inputs from the chemosensory system mediate opposite feeding responses to glucose in the wild-type and glucose-averse strains.}, number={7}, journal={Chemical Senses}, publisher={Oxford University Press (OUP)}, author={Wada-Katsumata, Ayako and Silverman, Jules and Schal, Coby}, year={2011}, month={Apr}, pages={589–600} }
 @article{guenard_silverman_2011, title={Tandem carrying, a new foraging strategy in ants: description, function, and adaptive significance relative to other described foraging strategies}, volume={98}, DOI={10.1007/s00114-011-0814-z}, abstractNote={An important aspect of social insect biology lies in the expression of collective foraging strategies developed to exploit food. In ants, four main types of foraging strategies are typically recognized based on the intensity of recruitment and the importance of chemical communication. Here, we describe a new type of foraging strategy, "tandem carrying", which is also one of the most simple recruitment strategies, observed in the Ponerinae species Pachycondyla chinensis. Within this strategy, workers are directly carried individually and then released on the food resource by a successful scout. We demonstrate that this recruitment is context dependent and based on the type of food discovered and can be quickly adjusted as food quality changes. We did not detect trail marking by tandem-carrying workers. We conclude by discussing the importance of tandem carrying in an evolutionary context relative to other modes of recruitment in foraging and nest emigration.}, number={8}, journal={Naturwissenschaften (Berlin, Germany)}, author={Guenard, B. and Silverman, J.}, year={2011}, pages={651–659} }
 @article{brightwell_silverman_2011, title={The Argentine Ant Persists Through Unfavorable Winters Via a Mutualism Facilitated By a Native Tree}, volume={40}, ISSN={["1938-2936"]}, DOI={10.1603/en11038}, abstractNote={ABSTRACT 
 Mutualisms and facilitations can fundamentally change the relationship between an organism's realized and fundamental niche. Invasive species may prove particularly suitable models for investigating this relationship as many are dependent on finding new partners for successful establishment. We conducted field-based experiments testing whether a native tree facilitates the successful survival of the invasive Argentine ant, Linepithema humile (Mayr), through unfavorable winter conditions in the southeastern United States. We found Argentine ant nests aggregated around the native loblolly pine, Pinus taeda L., during the winter months. The bark of this tree absorbed enough radiant solar energy to reach temperatures suitable for Argentine ant foraging even when ambient temperatures should have curtailed all foraging. Conversely, foraging ceased when the trunk was shaded. The sun-warmed bark of this tree gave the Argentine ant access to a stable honeydew resource. Argentine ants were not found on or near deciduous trees even though bark temperatures were warm enough to permit Argentine ant foraging on cold winter days. Augmenting deciduous trees with sucrose water through the winter months lead to Argentine ant nests remaining at their base and Argentine ants foraging on the tree. The Argentine ant requires both foraging opportunity and a reliable winter food source to survive through unfavorable winter conditions in the southeastern United States. The loblolly pine provided both of these requirements extending the realized niche of Argentine ants beyond its fundamental niche.}, number={5}, journal={ENVIRONMENTAL ENTOMOLOGY}, author={Brightwell, Robert J. and Silverman, Jules}, year={2011}, month={Oct}, pages={1019–1026} }
 @article{bednar_silverman_2011, title={Use of termites, Reticulitermes virginicus, as a springboard in the invasive success of a predatory ant, Pachycondyla (=Brachyponera) chinensis}, volume={58}, ISSN={["1420-9098"]}, DOI={10.1007/s00040-011-0163-0}, number={4}, journal={INSECTES SOCIAUX}, author={Bednar, D. M. and Silverman, J.}, year={2011}, month={Nov}, pages={459–467} }
 @article{rowles_silverman_2010, title={Argentine Ant Invasion Associated With Lob lolly Pines in the Southeastern United States: Minimal Impacts But Seasonally Sustained}, volume={39}, ISSN={["1938-2936"]}, DOI={10.1603/en10004}, abstractNote={ABSTRACT Invasive ants are notorious for directly displacing native ant species. Although such impacts are associated with Argentine ant invasions (Linepithema humile) worldwide, impacts within natural habitat are less widely reported, particularly those affecting arboreal ant communities. Argentine ants were detected in North Carolina mixed pine-hardwood forest for the first time but were localized on and around loblolly pines (Pinus taeda), probably because of association with honeydew-producing Hemiptera. We explored the potential impacts of L. humile on arboreal and ground-foraging native ant species by comparing interspersed loblolly pines invaded and uninvaded by Argentine ants. Impacts on native ants were assessed monthly over 1 yr by counting ants in foraging trails on pine trunks and in surrounding plots using a concentric arrangement of pitfall traps at 1, 2, and 3 m from the base of each tree. Of floristics and habitat variables, higher soil moisture in invaded plots was the only difference between plot types, increasing confidence that any ant community differences were caused by Argentine ants. Overall patterns of impact were weak. Composition differed significantly between Argentine ant invaded and uninvaded trunks and pitfalls but was driven only by the presence of Argentine ants rather than any resulting compositional change in native ant species. Native ant abundance and richness were similarly unaffected by L. humile. However, the abundance of individual ant species was more variable. Although numbers of the arboreal Crematogaster ashmeadi (Myrmicinae) declined on and around invaded pines, epigeic Aphaenogaster rudis (Myrmicinae) remained the most abundant species in all plots. Argentine ant densities peaked in late summer and fall, therefore overlapping with most native ants. Unexpected was their continued presence during even the coldest months. We provide evidence that Argentine ants can invade and persist in native North Carolina forests, probably mediated by pine-associated resources. However, their localized distribution and minimal impact on the native ant fauna relative to previously described invasions requires further resolution.}, number={4}, journal={ENVIRONMENTAL ENTOMOLOGY}, author={Rowles, Alexei D. and Silverman, Jules}, year={2010}, month={Aug}, pages={1141–1150} }
 @article{brightwell_bambara_silverman_2010, title={Combined Effect of Hemipteran Control and Liquid Bait on Argentine Ant Populations}, volume={103}, ISSN={["1938-291X"]}, DOI={10.1603/ec10150}, abstractNote={ABSTRACT 
 The invasive Argentine ant, Linepithema humile (Mayr), has become a worldwide problem capable of inflicting significant ecological and economic injury on urban, agricultural, and natural environments. The mobility of this pest ant has long been noted, rapidly moving nests to new food resources and then away as resources are depleted. This ant, like many pest ant species, has a special affinity for honeydew excreted by phloem-feeding Hemiptera. We investigated the effect of various hemipteran control strategies on terrapin scale densities and measured their indirect effect on local Argentine ant densities and foraging effort. We then determined whether this indirect treatment strategy improved the performance of an ant bait. We predicted that Argentine ants would move nests away from trees treated for Hemiptera and then move nests back when a liquid bait was offered, followed by a decline in ant numbers due to intake of the toxicant. A horticultural oil spray and soil application of the systemic insecticide, imidacloprid, had no effect on terrapin scale numbers. However, trunk-injected dicrotophos caused a reduction in scale and a decline in local Argentine ant nest density and canopy foraging effort. We also recorded a reduction in local Argentine ant ground foraging when large amounts of liquid bait were applied, and we found no evidence that combining dicrotophos with liquid ant bait performed better than each treatment alone. We suggest that a strategy of combined hemipteran control plus application of liquid ant bait can reduce local Argentine ant densities, when both components of this system are highly efficacious.}, number={5}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Brightwell, R. J. and Bambara, S. B. and Silverman, J.}, year={2010}, month={Oct}, pages={1790–1796} }
 @article{powell_silverman_2010, title={Impact of Linepithema humile and Tapinoma sessile (Hymenoptera: Formicidae) on three natural enemies of Aphis gossypii (Hemiptera: Aphididae)}, volume={54}, ISSN={["1049-9644"]}, DOI={10.1016/j.biocontrol.2010.05.013}, abstractNote={Ants frequently protect honeydew-excreting hemipterans from their natural enemies in exchange for food, and these interactions can have a negative impact on biological control. Invasive ant species, such as the Argentine ant, Linepithema humile (Mayr), enter into mutualisms with some hemipteran species and are generally regarded as more aggressive than native ants. Consequently, they may be more effective at protecting honeydew-producing hemipterans from natural enemy attack. We compared changes in populations of Aphis gossypii (Glover) tended by equal numbers of invasive L. humile, and the North America native Tapinoma sessile (Say), when exposed to the natural enemies Chrysoperla carnea (Stephens), Hippodamia convergens (Guer.) and Aphidius colemani (Viereck). While more L. humile than T. sessile workers foraged on plants with A. gossypii, both ants were equally effective at protecting A. gossypii from their natural enemies when aphid populations were relatively low. Using larger starting populations, A. gossypii were less negatively impacted by C. carnea or H. convergens when tended by L. humile than T. sessile. In a field experiment, the number of Aphis gossypii on plants with L. humile or T. sessile were greater than on plants without ants. We conclude that due to its higher foraging tempo L. humile may more effectively patrol plant surfaces supporting honeydew-producing hemipterans than T. sessile, which may, in part, underlie the success of this invasive ant.}, number={3}, journal={BIOLOGICAL CONTROL}, author={Powell, Bradford E. and Silverman, Jules}, year={2010}, month={Sep}, pages={285–291} }
 @article{menke_booth_dunn_schal_vargo_silverman_2010, title={Is It Easy to Be Urban? Convergent Success in Urban Habitats among Lineages of a Widespread Native Ant}, volume={5}, ISSN={1932-6203}, url={http://dx.doi.org/10.1371/journal.pone.0009194}, DOI={10.1371/journal.pone.0009194}, abstractNote={The most rapidly expanding habitat globally is the urban habitat, yet the origin and life histories of the populations of native species that inhabit this habitat remain poorly understood. We use DNA barcoding of the COI gene in the widespread native pest ant Tapinoma sessile to test two hypotheses regarding the origin of urban populations and traits associated with their success. First, we determine if urban samples of T. sessile have a single origin from natural populations by looking at patterns of haplotype clustering from across their range. Second, we examine whether polygynous colony structure – a trait associated with invasion success – is correlated with urban environments, by studying the lineage dependence of colony structure. Our phylogenetic analysis of 49 samples identified four well supported geographic clades. Within clades, Kimura-2 parameter pairwise genetic distances revealed <2.3% variation; however, between clade genetic distances were 7.5–10.0%, suggesting the possibility of the presence of cryptic species. Our results indicate that T. sessile has successfully colonized urban environments multiple times. Additionally, polygynous colony structure is a highly plastic trait across habitat, clade, and haplotype. In short, T. sessile has colonized urban habitats repeatedly and appears to do so using life history strategies already present in more natural populations. Whether similar results hold for other species found in urban habitats has scarcely begun to be considered.}, number={2}, journal={PLoS ONE}, publisher={Public Library of Science (PLoS)}, author={Menke, Sean B. and Booth, Warren and Dunn, Robert R. and Schal, Coby and Vargo, Edward L. and Silverman, Jules}, editor={Moreau, Corrie S.Editor}, year={2010}, month={Feb}, pages={e9194} }
 @article{brightwell_labadie_silverman_2010, title={Northward Expansion of the Invasive Linepithema humile (Hymenoptera: Formicidae) in the Eastern United States is Constrained by Winter Soil Temperatures}, volume={39}, ISSN={["0046-225X"]}, DOI={10.1603/en09345}, abstractNote={ARSTRACT 
 The invasive Argentine ant, Linepithema humile (Mayr) (Hymenoptera: Formicidae) has been evident in the North Carolina Piedmont, United States for 90 yr but has failed to spread further north. We investigated the mechanisms preventing this expansion. The Argentine ant ceases foraging at temperatures below 5°C and we hypothesized that winter soil temperatures at higher latitudes restricted foraging long enough to cause colony starvation. We tested if the Argentine ant could successfully feed at temperatures below 5°C and found that colonies would starve. We subjected Argentine ant nests to a range of sub- and above-freezing temperatures and measured worker mortality at various time intervals. We found that Argentine ant colonies will collapse after 8.5 d at 5°C Argentine ants can escape ambient cold temperatures by moving nests into the soil column. We tested how deeply into the soil Argentine ant queens and workers need to move to survive winter in North Carolina. Soil temperatures in the North Carolina Piedmont do not fall below 5°C for longer than nine consecutive days; therefore, Argentine ant colonies need only to retreat a few centimeters into the soil column to escape unsuitable temperatures. Winter soil temperature data from four climate stations situated from latitudes 35°, the current Eastern United States latitudinal limit for Argentine ant population expansion, to 39° were searched for periods where soil temperatures would have led to colony extirpation. North of their current distributions, extended periods of soil temperatures below 5°C regularly occur, preventing Argentine ant colonies from persisting.}, number={5}, journal={ENVIRONMENTAL ENTOMOLOGY}, author={Brightwell, R. J. and Labadie, P. E. and Silverman, J.}, year={2010}, month={Oct}, pages={1659–1665} }
 @article{powell_silverman_2010, title={Population growth of Aphis gossypii and Myzus persicae (Hemiptera: Aphididae) in the presence of Linepithema humile and Tapinoma sessile (Hymenoptera: Formicidae)}, volume={39}, number={5}, journal={Environmental Entomology}, author={Powell, B. E. and Silverman, J.}, year={2010}, pages={1492–1499} }
 @article{menke_guenard_sexton_weiser_dunn_silverman_2011, title={Urban areas may serve as habitat and corridors for dry-adapted, heat tolerant species; an example from ants}, volume={14}, ISSN={["1573-1642"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-79955054212&partnerID=MN8TOARS}, DOI={10.1007/s11252-010-0150-7}, number={2}, journal={URBAN ECOSYSTEMS}, author={Menke, Sean B. and Guenard, Benoit and Sexton, Joseph O. and Weiser, Michael D. and Dunn, Robert R. and Silverman, Jules}, year={2011}, month={Jun}, pages={135–163} }
 @article{rowles_silverman_2009, title={Carbohydrate supply limits invasion of natural communities by Argentine ants}, volume={161}, ISSN={["1432-1939"]}, DOI={10.1007/s00442-009-1368-z}, abstractNote={The ability of species to invade new habitats is often limited by various biotic and physical factors or interactions between the two. Invasive ants, frequently associated with human activities, flourish in disturbed urban and agricultural environments. However, their ability to invade and establish in natural habitats is more variable. This is particularly so for the invasive Argentine ant (Linepithema humile). While biotic resistance and low soil moisture limits their invasion of natural habitats in some instances, the effect of food availability has been poorly explored. We conducted field experiments to determine if resource availability limits the spread and persistence of Argentine ants in remnant natural forest in North Carolina. Replicated transects paired with and without sucrose solution feeding stations were run from invaded urban edges into forest remnants and compared over time using baits and direct counts at feeding stations. Repeated under different timing regimes in 2006 and 2007, access to sucrose increased local Argentine ant abundances (1.6-2.5 fold) and facilitated their progression into the forest up to 73 +/- 21% of 50-m transects. Resource removal caused an expected decrease in Argentine ant densities in 2006, in conjunction with their retreat to the urban/forest boundary. However, in 2007, Argentine ant numbers unexpectedly continued to increase in the absence of sugar stations, possibly through access to alternative resources or conditions not available the previous year such as honeydew-excreting Hemiptera. Our results showed that supplementing carbohydrate supply facilitates invasion of natural habitat by Argentine ants. This is particularly evident where Argentine ants continued to thrive following sugar station removal.}, number={1}, journal={OECOLOGIA}, author={Rowles, Alexei D. and Silverman, Jules}, year={2009}, month={Aug}, pages={161–171} }
 @article{vasquez_schal_silverman_2009, title={Colony Fusion in Argentine Ants is Guided by Worker and Queen Cuticular Hydrocarbon Profile Similarity}, volume={35}, ISSN={["1573-1561"]}, DOI={10.1007/s10886-009-9656-y}, abstractNote={Introduced populations of the Argentine ant, Linepithema humile, have experienced moderate to severe losses of genetic diversity, which may have affected nestmate recognition to various degrees. We hypothesized that cuticular hydrocarbons (CHC) serve as nestmate recognition cues, and facilitate colony fusion of unrelated L. humile colonies that share similar CHC profiles. In this study, we paired six southeastern U.S. L. humile colonies in a 6-month laboratory fusion assay, and determined if worker and queen CHC profile similarity between colonies was associated with colony fusion and intercolony genetic similarity. We also compared worker and queen CHC profiles between fused colony pairs and unpaired controls to determine if worker and queen chemical profiles changed after fusion. We found that colony fusion correlated with the CHC similarity of workers and queens, with the frequency of fusion increasing with greater CHC profile similarity between colonies. Worker and queen CHC profile similarity between colonies also was associated with genetic similarity between colonies. Queen CHC profiles in fused colonies appeared to be a mix of the two colony phenotypes. In contrast, when only one of the paired colonies survived, the CHC profile of the surviving queens did not diverge from that of the colony of origin. Similarly, workers in non-fused colonies maintained their colony-specific CHC, whereas in fused colonies the worker CHC profiles were intermediate between those of the two colonies. These results suggest a role for CHC in regulating interactions among mutually aggressive L. humile colonies, and demonstrate that colony fusion correlates with both genetic and CHC similarities. Further, changes in worker and queen chemical profiles in fused colonies suggest that CHC plasticity may sustain the cohesion of unrelated L. humile colonies that had fused.}, number={8}, journal={JOURNAL OF CHEMICAL ECOLOGY}, author={Vasquez, Gissella M. and Schal, Coby and Silverman, Jules}, year={2009}, month={Aug}, pages={922–932} }
 @article{brightwell_silverman_2009, title={Effects of Honeydew-Producing Hemipteran Denial on Local Argentine Ant Distribution and Boric Acid Bait Performance}, volume={102}, ISSN={["1938-291X"]}, DOI={10.1603/029.102.0340}, abstractNote={ABSTRACT 
 The Argentine ant is well known for its affinity for honeydew and is often associated with hemipteran outbreaks in agricultural and urban environments. It has been suggested that Argentine ants may be controlled by restricting access to honeydew, thereby forcing the ants to move or by encouraging increased liquid toxicant intake. We tested this possible control strategy by restricting Argentine ant access to the honeydew-producing terrapin scale within the canopy of red maple trees and monitoring ant numbers with pitfall traps and nest counts in the mulch around the tree base. Argentine ant nest numbers fell dramatically in the mulch around ant-excluded trees; however, there was no reduction in Argentine ant numbers caught in pitfalls around trees with or without canopy access. We added 0.5% boric acid bait stations at the base of the red maples and monitored bait consumption. Pitfall and nest counts were not affected by the addition of boric acid, although bait consumption was lower around ant-excluded trees, suggesting that restricting access to honeydew-producing Hemiptera did not enhance bait performance. We attribute this result to the increased distance Argentine ant workers had to trail from nest to bait station when not tending nearby terrapin scale. We suggest an alternative management strategy concentrating direct insecticidal control of Argentine ants around a few host plants infested with honeydew-producing Hemiptera by controlling Hemiptera in nearby host plants.}, number={3}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Brightwell, R. J. and Silverman, J.}, year={2009}, month={Jun}, pages={1170–1174} }
 @article{brightwell_silverman_2010, title={Invasive Argentine ants reduce fitness of red maple via a mutualism with an endemic coccid}, volume={12}, ISSN={["1573-1464"]}, DOI={10.1007/s10530-009-9607-0}, number={7}, journal={BIOLOGICAL INVASIONS}, author={Brightwell, Robert John and Silverman, Jules}, year={2010}, month={Jul}, pages={2051–2057} }
 @article{vasquez_schal_silverman_2008, title={Cuticular hydrocarbons as queen adoption cues in the invasive Argentine ant}, volume={211}, ISSN={["1477-9145"]}, DOI={10.1242/jeb.017301}, abstractNote={SUMMARYIn social insects, individuals typically recognize and behave aggressively towards alien conspecifics, thereby maintaining colony integrity. This is presumably achieved via a nestmate recognition system in which cuticular compounds, usually cuticular hydrocarbons (CHC), of genetic and/or environmental origin serve as recognition cues. Most invasive populations of the Argentine ant, Linepithema humile (Mayr), display minimal nestmate–non-nestmate discrimination, resulting in low levels of intraspecific aggression allowing free movement of workers and queens among nests. However, invasive L. humile in the southeastern United States show relatively high levels of intraspecific aggression, and selectively adopt non-nestmate queens. Using behavioral assays and gas chromatography, we found an association between non-nestmate queen adoption and similarity of the CHC profiles of adopted and host colony queens. Also, nestmate and non-nestmate queen CHC profiles became more similar after adoption by queenless colonies. Furthermore, queens treated with non-nestmate queen CHC had distinct CHC profiles and were generally attacked by nestmate workers. We suggest that in L. humile, CHC are used as queen recognition cues, and that queen recognition errors are more likely to occur when the CHC profiles of non-nestmate and host colony queens are similar. Our findings provide further evidence for the complex and dynamic nature of L. humile nestmate discrimination, which may in part underlie the success of introduced populations of this invasive ant.}, number={8}, journal={JOURNAL OF EXPERIMENTAL BIOLOGY}, author={Vasquez, Gissella M. and Schal, Coby and Silverman, Jules}, year={2008}, month={Apr}, pages={1249–1256} }
 @article{brightwell_silverman_2007, title={Argentine ant foraging activity and interspecific competition in complete vs. queenless and broodless colonies}, volume={54}, ISSN={["1420-9098"]}, DOI={10.1007/s00040-007-0950-9}, number={4}, journal={INSECTES SOCIAUX}, author={Brightwell, R. J. and Silverman, J.}, year={2007}, pages={329–333} }
 @article{vasquez_silverman_2008, title={Intraspecific aggression and colony fusion in the Argentine ant}, volume={75}, ISSN={["1095-8282"]}, DOI={10.1016/j.anbehav.2007.06.019}, abstractNote={Unicolonial ants possess an unusual social system characterized by the absence of internest aggression resulting in expansive networks where individuals move freely among distant nests. The Argentine ant, Linepithema humile (Mayr), can form geographically vast and numerically large unicolonial populations, or supercolonies, a trait that has been linked to its ecological success in the introduced range, and is one of the few invasive ants in which native and introduced populations have been examined to elucidate the origins and maintenance of unicoloniality. Supercolony formation may result from mixing of genetically homogenous and nonaggressive colonies, or initially aggressive colonies harbouring the most common recognition alleles. In this study, we examined interactions between mutually aggressive L. humile colonies in the absence of barriers limiting intercolony encounters to determine whether aggressive interactions result in either colony elimination or fusion into new nonaggressive colonies. By pairing experimental laboratory and field colonies displaying varying levels of intraspecific aggression, we determined that pairs that did not fuse had higher numbers of workers fighting and killed than colony pairs that fused and that genetic and cuticular hydrocarbon similarity between colony pairs was correlated with both levels of intraspecific aggression and colony fusion. We suggest that selective fusion of initially aggressive colonies sharing certain recognition cues may be a proximate mechanism shaping L. humile social structure, leading ultimately to extreme unicoloniality in introduced populations when ecological conditions are favourable.}, journal={ANIMAL BEHAVIOUR}, author={Vasquez, Gissella M. and Silverman, Jules}, year={2008}, month={Feb}, pages={583–593} }
 @article{vasquez_silverman_2008, title={Queen acceptance and the complexity of nestmate discrimination in the Argentine ant}, volume={62}, ISSN={["1432-0762"]}, DOI={10.1007/s00265-007-0478-z}, number={4}, journal={BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY}, author={Vasquez, Gissella M. and Silverman, Jules}, year={2008}, month={Feb}, pages={537–548} }
 @article{silverman_brightwell_2008, title={The Argentine ant: Challenges in managing an invasive unicolonial pest}, volume={53}, ISSN={["1545-4487"]}, DOI={10.1146/annurev.ento.53.103106.093450}, abstractNote={ The Argentine ant, Linepithema humile, has invaded urban, agricultural, and natural habitats worldwide, causing economic damage and disrupting ecosystem processes. Introduced populations of L. humile and those of many other invasive ants tend to be unicolonial, forming expansive, multiqueened supercolonies that dominate native ant communities and challenge control practices in managed habitats. Argentine ant management typically entails the application of residual insecticide liquids, granules, or baits to only a portion of the colony, resulting in fairly rapid reinfestation. We suggest that prevailing control methodologies are incomplete and not compatible with the behavior, nesting habits, and population structure of this ant, and therefore, more aggressive management strategies are required. Successful eradication efforts against other invasive unicolonial ant species can provide useful insights for local-scale L. humile eradication. }, journal={ANNUAL REVIEW OF ENTOMOLOGY}, author={Silverman, Jules and Brightwell, Robert John}, year={2008}, pages={231–252} }
 @article{buczkowski_silverman_2006, title={Geographical variation in Argentine ant aggression behaviour mediated by environmentally derived nestmate recognition cues}, volume={71}, ISSN={["0003-3472"]}, DOI={10.1016/j.anbehav.2005.04.012}, abstractNote={Social insects use a complex of recognition cues when discriminating nestmates from non-nestmate conspecifics. In the Argentine ant, Linepithema humile, recognition cues can be derived from exogenous sources, and L. humile acquires prey-derived hydrocarbons that are used in nestmate discrimination. We studied Argentine ant population-level distinctions in response to external recognition cues. Ants belonging to a California population were strongly affected by the imposition of prey-derived hydrocarbons, with spatially isolated colony fragments that had been fed different cockroach prey (Blattella germanica or Supella longipalpa) showing high and injurious intracolony aggression when reunited. In contrast, colonies of Argentine ants from the southeastern U.S. showed only moderate and noninjurious aggression when subjected to the same treatment. Field-collected colonies of L. humile had hydrocarbons in the range of those provided by S. longipalpa, and colonies from the southeastern U.S. had significantly higher initial levels of Supella-shared hydrocarbons. When fed cockroaches, Argentine ants from both regions acquired additional amounts of Supella- and Blattella-specific hydrocarbons, with a significant increase in levels of Blattella-specific hydrocarbons. Therefore, diet partitioning produced a greater change in the proportion of prey hydrocarbons in the California than in the southeastern U.S. populations, which may be responsible for the altered behaviour observed in the California population. Identifying factors underlying geographical variation in cue expression and/or perception may bring us closer to elucidating the selective forces driving nestmate recognition systems.}, journal={ANIMAL BEHAVIOUR}, author={Buczkowski, G and Silverman, J}, year={2006}, month={Feb}, pages={327–335} }
 @article{silverman_sorenson_waldvogel_2006, title={Trap-mulching Argentine ants}, volume={99}, DOI={10.1093/jee/99.5.1757}, number={5}, journal={Journal of Economic Entomology}, author={Silverman, J. and Sorenson, C. E. and Waldvogel, M. G.}, year={2006}, pages={1757–1760} }
 @article{buczkowski_silverman_2005, title={Context-dependent nestmate discrimination and the effect of action thresholds on exogenous cue recognition in the Argentine ant}, volume={69}, ISSN={["1095-8282"]}, DOI={10.1016/j.anbehav.2004.06.027}, abstractNote={The optimal acceptance threshold model predicts that kin/nestmate discrimination is context dependent and that, in a fluctuating environment, the action component of nestmate discrimination is plastic, rather than static. We examined changes in intraspecific aggression among colonies of Argentine ants, Linepithema humile, in various discrimination contexts, and found that aggression occurred at higher rates when either nestmates or familiar territory indicated nest proximity, but not when social context was absent, thereby providing additional support for the optimal acceptance threshold model. Context-dependent aggression in the Argentine ant appears to result from a shift in acceptance threshold in response to fitness costs associated with accepting nonkin. The change in the action component of Argentine ant nestmate discrimination was explained to some degree by the hypothesis that the presence of nestmates indicates nest proximity and denotes a fitness payoff for active defence (nest indicator hypothesis) and by the hypothesis that nestmates share the cost of nest defence in groups, but not singly (cost minimizer hypothesis). Isolated nest referents (familiar territory, conspecific brood, or single familiar nestmates), however, had no effect on aggression thresholds. We provide mixed support for the hypothesis that workers from genetically less diverse colonies attack workers from more diverse colonies. We found that, in the context of nest defence, genetically more diverse colonies initiated attacks on colonies with lower genetic diversity. Therefore, the role of asymmetrical aggression in reducing genetic diversity within introduced populations of L. humile remains unknown and other extrinsic factors such as nest status and/or colony size may affect the outcome of aggressive interactions in the field. Finally, our finding that colonies reared under uniform conditions showed diminished intraspecific aggression only when assayed in a social and/or ecological context underscores the importance of using appropriate aggression assays for testing patterns of intercolony aggression in L. humile, and that the use of different rearing regimes, source colonies and collection times may produce contradictory results.}, journal={ANIMAL BEHAVIOUR}, author={Buczkowski, G and Silverman, J}, year={2005}, month={Mar}, pages={741–749} }
 @article{buczkowski_kumar_suib_silverman_2005, title={Diet-related modification of cuticular hydrocarbon profiles of the Argentine ant, Linepithema humile, diminishes intercolony aggression}, volume={31}, ISSN={["1573-1561"]}, DOI={10.1007/s10886-005-3547-7}, abstractNote={Territorial boundaries between conspecific social insect colonies are maintained through a highly developed nestmate recognition system modulated by heritable and, in some instances, nonheritable cues. Argentine ants, Linepithema humile, use both genetic and environmentally derived cues to discriminate nestmates from nonnestmates. We explored the possibility that intraspecific aggression in the Argentine ant might diminish when colonies shared a common diet. After segregating recently field-collected colony pairs into high or moderate aggression categories, we examined the effect of one of three diets: two hydrocarbon-rich insect prey, Blattella germanica and Supella longipalpa, and an artificial (insect-free) diet, on the magnitude of aggression loss. Aggression diminished between colony pairs that were initially moderately aggressive. However, initially highly aggressive colony pairs maintained high levels of injurious aggression throughout the study, independent of diet type. Each diet altered the cuticular hydrocarbon profile by contributing unique, diet-specific cues. We suggest that acquisition of common exogenous nestmate recognition cues from shared food sources may diminish aggression and promote fusion in neighboring colonies of the Argentine ant.}, number={4}, journal={JOURNAL OF CHEMICAL ECOLOGY}, author={Buczkowski, G and Kumar, R and Suib, SL and Silverman, J}, year={2005}, month={Apr}, pages={829–843} }
 @article{alder_silverman_2005, title={Effects of interspecific competition between two urban ant species, Linepithema humile and Monomorium minimum, on toxic bait performance}, volume={98}, ISSN={["1938-291X"]}, DOI={10.1093/jee/98.2.493}, abstractNote={We evaluated the effects of interspecific competition on ant bait performance with two urban pest ants, the Argentine ant, Linepithema humile (Mayr), and the little black ant, Monomorium minimum (Buckley). In a laboratory study, the impact of a solid sulfluramid bait on M. minimum was diminished when L. humile were present, whereas the presence of M. minimum reduced the performance of a liquid fipronil bait against L. humile. Argentine ants were not adversely affected by sulfluramid bait at any time, whereas M. minimum was unaffected by fipronil bait until 14 d of exposure. In field studies measuring diel foraging activity, M. minimum seemed to delay L. humile foraging to food stations by approximately 30 min during summer 2001. However, L. humile subsequently recruited to food stations in very high numbers, thereby displacing M. minimum. L. humile visited food stations over an entire 24-h period, whereas M. minimum was only observed visiting food stations during daylight hours. Adjusting the timing of bait placement in the field may minimize any negative effects of interspecific competition between these two species on toxic bait performance.}, number={2}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Alder, P and Silverman, J}, year={2005}, month={Apr}, pages={493–501} }
 @article{alder_silverman_2004, title={A  comparison of monitoring methods used to detect changes in Argentine ant (Hymenoptera: Formicidae) populations}, volume={21}, number={3}, journal={Journal of Agricultural and Urban Entomology}, author={Alder, P. and Silverman, J.}, year={2004}, pages={142–149} }
 @article{buczkowski_vargo_silverman_2004, title={The diminutive supercolony: the Argentine ants of the southeastern United States}, volume={13}, ISSN={["1365-294X"]}, DOI={10.1111/j.1365-294X.2004.02261.x}, abstractNote={AbstractNative to Argentina and Brazil, the Argentine ant (Linepithema humile) is an invasive species that has become established on six continents and many oceanic islands. In several parts of its introduced range, including the western United States, southern Europe and Chile, the Argentine ant is unicolonial, forming extensive supercolonies. We examined population genetic structure and intercolony aggression in two regions of the introduced range of this species in the United States: California and the southeastern United States. Our results show that the southeastern L. humile population has high genotypic variability and strong intercolony aggression relative to the California population. In the California population, intercolony aggression was absent and 23 alleles were found across seven polymorphic microsatellite loci. However, in the Southeast, aggression between colonies was high and 47 alleles were present across the same seven loci in an equal number of colonies. We suggest that distinctly different colonization patterns for California and the Southeast may be responsible for the striking disparity in the genetic diversity of introduced populations. Southeastern colonies may have descended from multiple, independent introductions from the native range, undergoing a bottleneck at each introduction. In contrast, the California supercolony may have originated from one or more colonies inhabiting the southeastern United States, thus experiencing a double bottleneck. The differences in present‐day distribution patterns between California and the Southeast may be due to the combined effect of two factors: lower winter temperatures in the Southeast and/or competition with another successful and widely distributed ant invader, the fire ant Solenopsis invicta.}, number={8}, journal={MOLECULAR ECOLOGY}, author={Buczkowski, G and Vargo, EL and Silverman, J}, year={2004}, month={Aug}, pages={2235–2242} }
 @article{meissner_silverman_2003, title={Effect of aromatic cedar mulch on Argentine ant (Hymenoptera : Formicidae) foraging activity and nest establishment}, volume={96}, ISSN={["1938-291X"]}, DOI={10.1603/0022-0493-96.3.850}, abstractNote={Abstract In the laboratory, Argentine ant, Linepithema humile (Mayr), mortality was positively correlated to the length of an aromatic cedar mulch section that had to be crossed before food could be reached. When ants could access food without crossing the mulch, mortality was not correlated to mulch section length. In the field, Argentine ants showed a tendency to avoid aromatic cedar mulch as a nesting substrate. In plant beds alongside buildings the number of ant nests (pockets containing brood) found was not significantly different between aromatic cedar and cypress mulch. However, when pine straw mulch around oak trees was replaced with aromatic cedar or cypress mulch, a similar number of ant nests was found in the cypress mulch as in the original pine straw, whereas numbers in aromatic cedar mulch were significantly lower. Also, fewer ants were trailing on the trees surrounded by aromatic cedar mulch compared with cypress mulch or the original pine straw. The number of ants attracted to apple jelly baits placed alongside the buildings did not differ between mulch types; neither did the number of ant trails crossing the mulch beds around the buildings. We suggest that aromatic cedar mulch may help control Argentine ants and reduce insecticide input when applied in combination with conventional control methods.}, number={3}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Meissner, HE and Silverman, J}, year={2003}, month={Jun}, pages={850–855} }
 @article{roulston_buczkowski_silverman_2003, title={Nestmate discrimination in ants: effect of bioassay on aggressive behavior}, volume={50}, ISSN={["1420-9098"]}, DOI={10.1007/s00040-003-0624-1}, number={2}, journal={INSECTES SOCIAUX}, author={Roulston, TH and Buczkowski, G and Silverman, J}, year={2003}, pages={151–159} }
 @article{silverman_roulston_2003, title={Retrieval of granular bait by the Argentine ant (Hymenoptera : Formicidae): Effect of clumped versus scattered dispersion patterns}, volume={96}, ISSN={["1938-291X"]}, DOI={10.1603/0022-0493-96.3.871}, abstractNote={Abstract Argentine ants, Linepithema humile (Mayr), use mass recruitment foraging, with clumped prey items being retrieved more efficiently than dispersed prey. However, in prior field experiments, granular baits, whether dispensed in containers or broadly scattered, had a similar impact on Argentine ant populations. In laboratory experiments, granular insecticide bait was encountered faster by Argentine ant workers and more granules were initially returned to the colony when the granules were scattered versus clumped. After 2 h, granules from both dispersion patterns were retrieved equally. Our results suggest that Argentine ant colonies adjust their foraging patterns to resources of different quality (prey versus bait). Also, foraging activity patterns for bait in the laboratory are consistent with prior field results demonstrating no efficacy advantages to discrete granular bait placements.}, number={3}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Silverman, J and Roulston, TH}, year={2003}, month={Jun}, pages={871–874} }
 @article{roulston_silverman_2002, title={The effect of food size and dispersion pattern on retrieval rate by the Argentine ant, Linepithema humile (Hymenoptera : formicidae)}, volume={15}, ISSN={["1572-8889"]}, DOI={10.1023/A:1020791705673}, number={5}, journal={JOURNAL OF INSECT BEHAVIOR}, author={Roulston, TH and Silverman, J}, year={2002}, month={Sep}, pages={633–648} }
 @article{silverman_roulston_2001, title={Acceptance and intake of gel and liquid sucrose compositions by the argentine ant (Hymenoptera : Formicidae)}, volume={94}, ISSN={["1938-291X"]}, DOI={10.1603/0022-0493-94.2.511}, abstractNote={Abstract Liquids and gels are common delivery forms used in commercial ant baits, but the relative effectiveness of each is unknown. We compared the feeding responses of the Argentine ant, Linepithema humile (Mayr), to liquid and gel compositions of sucrose. In choice assays, more workers were counted on gel than liquid; however, substantially more liquid was consumed. Because workers could stand on the gel, more workers could feed simultaneously on the gel. The feeding bouts of individual workers, however, were much less efficient at extracting sucrose in gel form. Workers fed eightfold longer on the gel, yet removed fivefold less sucrose than workers feeding on liquid. This potential bias should be considered during attraction and palatability studies that use physically different bait compositions. When the toxicant fipronil was added to the compositions, a greater proportion of the colony died after workers had fed on liquid than gel baits. This finding suggests that liquid formulations may provide more effective control of Argentine ants due to the greater speed and abundance in which it is ingested.}, number={2}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Silverman, J and Roulston, TH}, year={2001}, month={Apr}, pages={511–515} }
 @article{silverman_liang_2001, title={Colony disassociation following diet partitioning in a unicolonial ant}, volume={88}, DOI={10.1007/s001140000198}, abstractNote={Discriminating nestmates from alien conspecifics via chemical cues is recognized as a critical element in maintaining the integrity of insect societies. We determined, in laboratory experiments, that nestmate recognition in an introduced population of the Argentine ant, Linepithema humile, is modified by hydrocarbons acquired from insect prey, and that workers from spatially isolated colony fragments, each provided with prey that possessed distinct cuticular hydrocarbons, displayed aggressive behavior towards their former nestmates. Isolation for 28 days or more between colony fragments fed different prey was sufficient to prevent re-establishment of inter-nest communication for at least an additional 28 days through the introduction of a bridge between the nests. Ants possessed intrinsic cuticular hydrocarbons plus only those hydrocarbons from the prey they received during the isolation period. Colony fragments which were isolated for less than 28 days reunited with workers possessing both prey hydrocarbons. Therefore, L. humile nestmate recognition may be dynamic, being in part dependent on the spatio-temporal distribution of prey, along with physical factors permitting or restricting access of subcolony units to those prey.}, number={2}, journal={Naturwissenschaften (Berlin, Germany)}, author={Silverman, J. and Liang, D.}, year={2001}, pages={73–77} }
 @article{meissner_silverman_2001, title={Effects of aromatic cedar mulch on the Argentine ant and the odorous house ant (Hymenoptera : Formicidae)}, volume={94}, ISSN={["1938-291X"]}, DOI={10.1603/0022-0493-94.6.1526}, abstractNote={Abstract In laboratory studies, the Argentine ant, Linepithema humile (Mayr), and the odorous house ant, Tapinoma sessile (Say), avoided aromatic cedar mulch as a nesting substrate. Both ant species were killed when confined with fresh aromatic cedar mulch in sealed containers. However, when confined with cedar mulch that had been aged outdoors for up to 140 d, mortality of L. humile was complete regardless of mulch age, whereas T. sessile mortality declined significantly over the mulch-aging period. Argentine ant susceptibility to aromatic cedar mulch was also greater than that of the odorous house ant when colonies were restricted to mulch in open trays. In addition, commercial aromatic cedar oil was lethal to both ant species. Our results suggest that aromatic cedar mulch may serve as an effective component of a comprehensive urban ant management program.}, number={6}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Meissner, HE and Silverman, J}, year={2001}, month={Dec}, pages={1526–1531} }
 @article{liang_blomquist_silverman_2001, title={Hydrocarbon-released nestmate aggression in the Argentine ant, Linepithema humile, following encounters with insect prey}, volume={129}, ISSN={["1879-1107"]}, DOI={10.1016/S1096-4959(01)00404-3}, abstractNote={Argentine ants, Linepithema humile, were attacked by their nestmates following contact with a particular prey item, the brown-banded cockroach, Supella longipalpa. Contact with prey, as brief as 2 min, provoked nestmate aggression. Argentine ants contaminated with hydrocarbons extracted from S. longipalpa also released nestmate aggression behavior similar to that released by the whole prey item, confirming the involvement of hydrocarbons. In contrast to S. longipalpa, little or no nestmate aggression was induced by other ant prey from diverse taxa. A comparison of prey hydrocarbon profiles revealed that all hydrocarbons of S. longipalpa were very long chain components with 33 or more carbons, while other prey had either less, or none, of the very long chain hydrocarbons of 33 carbons or greater. We identified the hydrocarbons of S. longipalpa and some new groups of long chain hydrocarbons of L. humile. The majority of S. longipalpa hydrocarbons were 35 and 37 carbons in length with one to three methyl branches, and closely resembled two previously unidentified groups of compounds from L. humile of similar chain length. The hydrocarbons of S. longipalpa and L. humile were compared and their role in the Argentine ant nestmate recognition is discussed.}, number={4}, journal={COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY}, author={Liang, D and Blomquist, GJ and Silverman, J}, year={2001}, month={Jul}, pages={871–882} }
 @article{liang_silverman_2000, title={"You are what you eat": Diet modifies cuticular hydrocarbons and nestmate recognition in the Argentine ant, Linepithema humile}, volume={87}, ISSN={["1432-1904"]}, DOI={10.1007/s001140050752}, abstractNote={Nestmate recognition plays a key role in the behavior and evolution of social insects. We demonstrated that hydrocarbons are the chemical cues used in Argentine ant, Linepithema humile, nestmate recognition, and that these hydrocarbons can be acquired from insect prey. Consequently, Argentine ant cuticular hydrocarbon patterns reveal the same hydrocarbons present in their diet. Diet alters both the recognition cues present on the cuticular surface and the response of nestmates to this new colony odor, resulting in aggression between former nestmates reared on different insect prey.}, number={9}, journal={NATURWISSENSCHAFTEN}, author={Liang, D and Silverman, J}, year={2000}, month={Sep}, pages={412–416} }
 @article{silverman_nsimba_2000, title={Soil-free collection of Argentine ants (Hymenoptera : Formicidae) based on food-directed brood and queen movement}, volume={83}, ISSN={["1938-5102"]}, DOI={10.2307/3496222}, abstractNote={The movement of Argentine ant, Linepithema humile (Mayr), colonies was studied in the laboratory. Workers transported brood from the main colony to satellite nests within 2 h. Queens also moved into the satellite nests. Up to 70% of the brood were moved out of the main colony by 48 h. Although most of the brood and queens migrated to a satellite nest 60 cm from the main nest, a substantial number of brood and queens moved 12.2 m to a nest 60 cm from a food source. We subsequently employed these findings to induce a portion of a field colony of L. humile to enter artificial colony dishes within the laboratory. Workers, brood, and queens were collected continuously and effortlessly using this technique.}, number={1}, journal={FLORIDA ENTOMOLOGIST}, author={Silverman, J and Nsimba, B}, year={2000}, month={Mar}, pages={10–16} }
 @article{silverman_liang_1999, title={Effect of fipronil on bait formulation-based aversion in the German cockroach (Dictyoptera : Blattellidae)}, volume={92}, ISSN={["1938-291X"]}, DOI={10.1093/jee/92.4.886}, abstractNote={We examined the effects of 3 active ingredients in baits containing glucose on a behaviorally resistant (glucose-averse, T-164) strain of Blattella germanica L. Baits with glucose and hydramethylnon or chlorpyrifos killed few T-164 individuals; however, fipronil—glucose baits killed 60% of the cockroaches by day 14. Although ingestion levels were low, fipronil—glucose baits were consumed more than hydramethylnon or chlorpyrifos glucose baits by T-164 cockroaches. Fipronil bait was 17 and 29 times more toxic to the T-164 strain than hydramethylnon and chlorpyrifos, respectively. Despite aversion to a key bait component, low-level bait consumption of a highly active toxicant such as fipronil may to some degree override bait inert-based behavioral resistance mech- anisms.}, number={4}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Silverman, J and Liang, DS}, year={1999}, month={Aug}, pages={886–889} }