@article{principato_romero_lee_campbell_choe_schal_devries_2023, title={Histamine excretion in common indoor and hematophagous arthropods}, volume={8}, ISSN={["1938-2928"]}, url={https://doi.org/10.1093/jme/tjad103}, DOI={10.1093/jme/tjad103}, abstractNote={Abstract
               Histamine is a biogenic amine that regulates multiple physiological functions in diverse organisms, specifically playing a central role in the mammalian immune response. The common bed bug, Cimex lectularius L. (Hemiptera: Cimicidae), excretes histamine in large amounts in its feces as a component of its aggregation pheromone, which contaminates homes. The potential health risks associated with the presence of indoor histamine are unclear, but to predict future exposure risks, it is critical that we understand if other arthropods excrete histamine in any discernible phylogenetic pattern. In the present study, we evaluated histamine excretion by various arthropods; specifically those commonly found in large numbers indoors, other hematophagous species, and other species in the order Hemiptera. To evaluate arthropods for histamine excretion, rearing containers for each arthropod were swabbed and/or the harborage substrates were collected. Samples were then analyzed for the presence of histamine using gas chromatography–mass spectrometry. For those arthropods where histamine was present above the method detection limit, total histamine excretion was quantified over a period of 2 wk. Our results indicate that histamine excretion is limited to hematophagous hemipterans (bed bugs, bat bugs, tropical bed bugs, and kissing bugs), suggesting that indoor histamine contamination in the United States can be primarily linked to bed bugs.}, journal={JOURNAL OF MEDICAL ENTOMOLOGY}, author={Principato, Simona and Romero, Alvaro and Lee, Chow-Yang and Campbell, Kathleen and Choe, Dong-Hwan and Schal, Coby and DeVries, Zachary}, editor={Booth, WarrenEditor}, year={2023}, month={Aug} }
 @article{gordon_santangelo_gonzalez-morales_menechella_schal_devries_2023, title={Spatial distribution of histamine in bed bug-infested homes}, volume={880}, ISSN={["1879-1026"]}, DOI={10.1016/j.scitotenv.2023.163180}, abstractNote={Histamine is a component of the bed bug aggregation pheromone. It was recently identified as an environmental contaminant in homes with active bed bug infestations, posing a potential health risk to humans via skin contact or inhalation. It remains unclear how histamine is distributed in homes and if histamine can become airborne. In the present study, histamine levels in household dust were quantified from multiple locations within bed bug infested and uninfested apartments. Bed bug population levels were quantified using both traps and visual counts. The amount of histamine detected varied significantly with respect to sampling location, with the highest concentration of histamine quantified from bedding material. Infestation severity did not have a significant effect on histamine quantified at any location. Our results indicate that the bedroom should be the primary focus of histamine mitigation efforts, although histamine can be found throughout the home. Histamine quantified from homes without active bed bug infestations suggests that histamine from previous infestations can persist following pest eradication. These findings highlight the importance of histamine as a potential insect allergen and will be important for the development of targeted mitigation strategies of bed bug histamine.}, journal={SCIENCE OF THE TOTAL ENVIRONMENT}, author={Gordon, Johnalyn M. and Santangelo, Richard G. and Gonzalez-Morales, Maria A. and Menechella, Mark and Schal, Coby and DeVries, Zachary C.}, year={2023}, month={Jul} }
 @article{gaire_devries_mick_santangelo_bottillo_camera_schal_2021, title={Human skin triglycerides prevent bed bug (Cimex lectularius L.) arrestment}, volume={11}, ISSN={["2045-2322"]}, DOI={10.1038/s41598-021-01981-1}, abstractNote={AbstractBed bugs (Cimex lectularius) have proliferated globally and have become one of the most challenging pests to control indoors. They are nocturnal and use multiple sensory cues to detect and orient towards their human hosts. After feeding, usually on a sleeping human, they return to a shelter on or around the sleeping surface, but not directly on the host. We hypothesized that although human skin odors attract hungry bed bugs, human skin compounds may also prevent arrestment on hosts. We used arrestment assays to test human skin swabs, extracts from human skin swabs, and pure compounds identified from human skin swabs. When given a choice, bed bugs preferred to arrest on substrates not previously conditioned by humans. These responses were consistent among laboratory-reared and apartment-collected bed bugs. The compounds responsible for this behavior were found to be extractable in hexane, and bed bugs responded to such extracts in a dose-dependent manner. Bioassay-guided fractionation paired with thin-layer chromatography, GC–MS, and LC–MS analyses suggested that triglycerides (TAGs), common compounds found on human skin, were preventing arrestment on shelters. Bed bugs universally avoided sheltering in TAG-treated shelters, which was independent of the number of carbons or the number of double bonds in the TAG. These results provide strong evidence that the complex of human skin compounds serve as multifunctional semiochemicals for bed bugs, with some odorants attracting host-seeking stages, and others (TAGs and possibly other compounds) preventing bed bug arrestment. Host chemistry, environmental conditions and the physiological state of bed bugs likely influence the dual nature behavioral responses of bed bugs to human skin compounds.}, number={1}, journal={SCIENTIFIC REPORTS}, author={Gaire, Sudip and DeVries, Zachary C. and Mick, Russell and Santangelo, Richard G. and Bottillo, Grazia and Camera, Emanuela and Schal, Coby}, year={2021}, month={Dec} }
 @article{saveer_devries_santangelo_schal_2021, title={Mating and starvation modulate feeding and host-seeking responses in female bed bugs, Cimex lectularius}, volume={11}, ISSN={["2045-2322"]}, url={https://doi.org/10.1038/s41598-021-81271-y}, DOI={10.1038/s41598-021-81271-y}, abstractNote={AbstractReproductive fitness and survival are enhanced by adaptive behaviors that are modulated by internal physiological states and external social contexts. The common bed bug,Cimex lectularius, is an obligate hematophagous ectoparasite that requires host blood for growth, development, and reproduction. We investigated how mating, starvation and social interactions affect host-seeking, blood feeding, oviposition, and survival of female bed bugs. The percentage of females that fed and the amount of blood they ingested were greater in mated females (90–100%) than in unmated females (48–60%). Mating state also modulated the female’s orientation towards human skin odor in an olfactometer; more mated (69%) than unmated (23%) females responded to human odors. The response rate of unmated females (60%) to skin odor increased with longer starvation period, while the opposite pattern was observed in mated females (20%). Although fecundity after a single blood meal was unaffected by long or short residence and interaction with males, females subjected to frequent copulation attempts had lower survivorship and lifespan than females housed with males for only 24 h. Taken together, these results indicate that by adaptively and coordinately expressing behaviors based on the internal physiological state, females maximize their survival and reproductive fitness.}, number={1}, journal={SCIENTIFIC REPORTS}, author={Saveer, Ahmed M. and DeVries, Zachary C. and Santangelo, Richard G. and Schal, Coby}, year={2021}, month={Jan} }
 @article{gonzalez-morales_devries_sierras_santangelo_kakumanu_schal_2021, title={Resistance to Fipronil in the Common Bed Bug (Hemiptera: Cimicidae)}, volume={58}, ISSN={["1938-2928"]}, url={https://doi.org/10.1093/jme/tjab040}, DOI={10.1093/jme/tjab040}, abstractNote={AbstractCimex lectularius L. populations have been documented worldwide to be resistant to pyrethroids and neonicotinoids, insecticides that have been widely used to control bed bugs. There is an urgent need to discover new active ingredients with different modes of action to control bed bug populations. Fipronil, a phenylpyrazole that targets the GABA receptor, has been shown to be highly effective on bed bugs. However, because fipronil shares the same target site with dieldrin, we investigated the potential of fipronil resistance in bed bugs. Resistance ratios in eight North American populations and one European population ranged from 1.4- to >985-fold, with highly resistant populations on both continents. We evaluated metabolic resistance mechanisms mediated by cytochrome P450s, esterases, carboxylesterases, and glutathione S-transferases using synergists and a combination of synergists. All four detoxification enzyme classes play significant but variable roles in bed bug resistance to fipronil. Suppression of P450s and esterases with synergists eliminated resistance to fipronil in highly resistant bed bugs. Target-site insensitivity was evaluated by sequencing a fragment of the Rdl gene to detect the A302S mutation, known to confer resistance to dieldrin and fipronil in other species. All nine populations were homozygous for the wild-type genotype (susceptible phenotype). Highly resistant populations were also highly resistant to deltamethrin, suggesting that metabolic enzymes that are responsible for pyrethroid detoxification might also metabolize fipronil. It is imperative to understand the origins of fipronil resistance in the development or adoption of new active ingredients and implementation of integrated pest management programs.}, number={4}, journal={JOURNAL OF MEDICAL ENTOMOLOGY}, publisher={Oxford University Press (OUP)}, author={Gonzalez-Morales, Maria A. and DeVries, Zachary and Sierras, Angela and Santangelo, Richard G. and Kakumanu, Madhavi L. and Schal, Coby}, editor={Hribar, LawrenceEditor}, year={2021}, month={Jul}, pages={1798–1807} }
 @article{gaire_schal_mick_devries_2020, title={The Role of Antennae in Heat Detection and Feeding Behavior in the Bed Bug (Hemiptera: Cimicidae)}, volume={113}, ISSN={["1938-291X"]}, url={https://doi.org/10.1093/jee/toaa250}, DOI={10.1093/jee/toaa250}, abstractNote={AbstractThe common bed bug (Cimex lectularius L.) is an obligate hematophagous ectoparasite that has significant impacts on human health and well-being. All life stages of bed bugs (except eggs) feed solely on blood, which is required to molt and reproduce. Bed bugs use multiple cues to locate their hosts, including heat, CO2, and body odors. Of these cues, detection of heat appears limited to a short distance of <3 cm. However, it remains unclear if bed bugs can detect radiant heat, what structure(s) are responsible for heat detection, and if heat detection via the antennae is required for feeding. In this study, bed bug response to radiant heat was evaluated using the two-choice T-maze assay with the heat source either in contact with the surface (i.e., conduction) or not in contact (i.e., radiation) in nonantennectomized bed bugs. Further, we systematically ablated the bed bug’s antennal segments (distal tip, first segment, and all four segments) and assessed their responses to heat and feeding in a unique two-choice T-maze assay and individual feeding assays, respectively. Our two-choice assays with contact to or no contact with the surface indicated that bed bugs cannot detect radiant heat. Later, we found that the distal tip of the terminal antennal segment is responsible for orientation toward a heat source. However, >50% of the bed bugs fed even when the entire antenna was removed, suggesting redundancy in sensory cues that drive feeding. These results will be used to better understand the role heat plays in bed bug host attraction and design of traps.}, number={6}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, publisher={Oxford University Press (OUP)}, author={Gaire, Sudip and Schal, Coby and Mick, Russell and DeVries, Zachary}, editor={Appel, ArthurEditor}, year={2020}, month={Dec}, pages={2858–2863} }
 @article{devries_santangelo_crissman_mick_schal_2019, title={Exposure risks and ineffectiveness of total release foggers (TRFs) used for cockroach control in residential settings}, volume={19}, ISSN={1471-2458}, url={http://dx.doi.org/10.1186/s12889-018-6371-z}, DOI={10.1186/s12889-018-6371-z}, abstractNote={The German cockroach, Blattella germanica, is one of the most challenging pests to eradicate from indoor environments. Professional pest control is often prohibitively expensive, prompting low-income residents to turn to over-the-counter consumer products, including total release foggers (TRFs, "bug bombs"). Despite their widespread use, little is known regarding either the associated pesticide exposure risks or the efficacy of TRFs. Cockroach-infested homes were recruited into the study. Wipe samples were collected from various surfaces before TRFs were discharged, immediately after, and one month later to determine pesticide exposure risks in 20 homes (divided equally among four different TRF products). Simultaneously, cockroach populations were monitored in all homes to assess the efficacy of TRFs. In parallel, 10 homes were treated with gel baits (divided equally between two bait products), to compare TRFs to a more targeted, low-risk, do-it-yourself intervention strategy. TRFs failed to reduce cockroach populations, whereas similarly priced gel baits caused significant declines in the cockroach populations. Use of TRFs resulted in significant pesticide deposits throughout the kitchen. Across all products, pesticides, and horizontal kitchen surfaces, pesticide residues following TRF discharge were 603-times (SEM ±184) higher than baseline, with a median increase of 85 times. The high risks of pesticide exposure associated with TRFs combined with their ineffectiveness in controlling German cockroach infestations call into question their utility in the marketplace, especially because similarly priced and much safer bait products are highly effective in the indoor environment.}, number={1}, journal={BMC Public Health}, publisher={Springer Science and Business Media LLC}, author={DeVries, Zachary C. and Santangelo, Richard G. and Crissman, Jonathan and Mick, Russell and Schal, Coby}, year={2019}, month={Jan} }
 @article{devries_santangelo_crissman_suazo_kakumanu_schal_2019, title={Pervasive Resistance to Pyrethroids in German Cockroaches (Blattodea: Ectobiidae) Related to Lack of Efficacy of Total Release Foggers}, volume={112}, ISSN={0022-0493 1938-291X}, url={http://dx.doi.org/10.1093/jee/toz120}, DOI={10.1093/jee/toz120}, abstractNote={Abstract
               Despite limited efficacy data, do-it-yourself (DIY) insecticide products often promise low-cost alternatives to professional pest control. Total release foggers (TRFs, ‘bug bombs’), which are prominent DIY products, were recently shown to be ineffective at reducing German cockroach (Blattella germanica L.) infestations, in contrast to highly effective baits. However, the reason(s) for TRF failure remain unknown. Therefore, we investigated insecticide resistance of apartment-collected cockroaches from homes where TRFs failed. In topical (direct) application assays, resistance to cypermethrin (a common active ingredient in TRFs) was 202 ± 33 times that of a laboratory insecticide-susceptible population (based on LD50 ratios), while resistance to fipronil, a common bait active ingredient, was considerably lower at 14 ± 2 times that of the laboratory insecticide-susceptible population. The addition of PBO, a P450 inhibitor that synergizes pyrethroids, enhanced the efficacy of cypermethrin, but only at high doses of cypermethrin. Additionally, >96% of screened cockroaches possessed at least one copy of the L993F mutation in the voltage-gated sodium channel, known to confer resistance to pyrethroids (knockdown resistance, kdr). Because TRF treatments killed insecticide-susceptible sentinel cockroaches but failed to kill apartment-collected cockroaches, these results suggest that pyrethroid resistance is a major factor contributing to the failure of TRFs. Multiple mechanisms of resistance, including metabolic detoxification of the pyrethroids and kdr mutations that confer target-site insensitivity, suggest that TRFs would lack efficacy against German cockroaches in residential settings, where high levels of pyrethroid resistance have been documented globally.}, number={5}, journal={Journal of Economic Entomology}, publisher={Oxford University Press (OUP)}, author={DeVries, Zachary C and Santangelo, Richard G and Crissman, Jonathan and Suazo, Alonso and Kakumanu, Madhavi L and Schal, Coby}, editor={Rust, MichaelEditor}, year={2019}, month={May}, pages={2295–2301} }
 @article{devries_saveer_mick_schal_2018, title={Bed Bug (Hemiptera: Cimicidae) Attraction to Human Odors: Validation of a Two-Choice Olfactometer}, volume={56}, ISSN={0022-2585 1938-2928}, url={http://dx.doi.org/10.1093/jme/tjy202}, DOI={10.1093/jme/tjy202}, abstractNote={AbstractBed bugs (Cimex lectularius L.) (Hemiptera: Cimicidae) are obligate hematophagous ectoparasites, and, therefore, must locate suitable hosts to ensure survival and reproduction. Their largely nocturnal activity suggests that chemosensory and thermosensory cues would play critical roles in host location. Yet, the importance of olfaction in host attraction of bed bugs remains unclear. We developed and validated a Y-tube, two-choice olfactometer and tested its suitability for investigating attraction to human odors (from skin swabs). Olfactometer orientation significantly affected the percentage of bed bugs that were activated by human odors, with significantly more bed bugs responding when the olfactometer was oriented vertically (bug introduced at bottom of the olfactometer) compared with all other orientations. Starved (7–10 d) adult males, mated females, and nymphs responded (47–77% moved up the olfactometer and made a choice) when human odors were present in the olfactometer, while starved, unmated females did not respond. Skin swabs from all five human participants elicited high response rates (65–82%), and bed bugs from four different populations responded to skin swabs (40–82% response rate). However, in all assays including those resulting in relatively low response rates, bed bugs exhibited >90% preference for human odors over blank controls. These results provide strong evidence that bed bugs can respond and orient towards human odors, independently of all other host cues. Furthermore, the validated olfactometer should enable rapid and efficient evaluations of bed bug behavioral responses to semiochemicals.}, number={2}, journal={Journal of Medical Entomology}, publisher={Oxford University Press (OUP)}, author={DeVries, Zachary C and Saveer, Ahmed M and Mick, Russell and Schal, Coby}, year={2018}, month={Nov}, pages={362–367} }
 @article{devries_santangelo_barbarin_schal_2018, title={Histamine as an emergent indoor contaminant: Accumulation and persistence in bed bug infested homes}, volume={13}, ISSN={1932-6203}, url={http://dx.doi.org/10.1371/journal.pone.0192462}, DOI={10.1371/journal.pone.0192462}, abstractNote={Histamine is used in bronchial and dermal provocation, but it is rarely considered an environmental risk factor in allergic disease. Because bed bugs defecate large amounts of histamine as a component of their aggregation pheromone, we sought to determine if histamine accumulates in household dust in bed bug infested homes, and the effects of bed bug eradication with spatial heat on histamine levels in dust. We collected dust in homes and analyzed for histamine before, and up to three months after bed bug eradication. Histamine levels in bed bug infested homes were remarkably high (mean = 54.6±18.9 μg/100 mg of sieved household dust) and significantly higher than in control homes not infested with bed bugs (mean < 2.5±1.9 μg/100 mg of sieved household dust). Heat treatments that eradicated the bed bug infestations failed to reduce histamine levels, even three months after treatment. We report a clear association between histamine levels in household dust and bed bug infestations. The high concentrations, persistence, and proximity to humans during sleep suggest that bed bug-produced histamine may represent an emergent contaminant and pose a serious health risk in the indoor environment.}, number={2}, journal={PLOS ONE}, publisher={Public Library of Science (PLoS)}, author={DeVries, Zachary C. and Santangelo, Richard G. and Barbarin, Alexis M. and Schal, Coby}, editor={Benoit, Joshua B.Editor}, year={2018}, month={Feb}, pages={e0192462} }
 @article{devries_mick_balvín_schal_2017, title={Aggregation behavior and reproductive compatibility in the family Cimicidae}, volume={7}, ISSN={2045-2322}, url={http://dx.doi.org/10.1038/s41598-017-12735-3}, DOI={10.1038/s41598-017-12735-3}, abstractNote={AbstractBed bugs (Cimex lectularius) provide a unique opportunity to understand speciation and host-associated divergence in parasites. Recently, two sympatric but genetically distinct lineages ofC. lectulariuswere identified: one associated with humans and one associated with bats. We investigated two mechanisms that could maintain genetic differentiation in the field: reproductive compatibility (via mating crosses) and aggregation fidelity (via two-choice sheltering assays). Effects were assessed at the intra-lineage level (within human-associated bed bugs), inter-lineage level (between human- and bat-associated bed bugs), and inter-species level (betweenC. lectulariusandCimex pipistrelli[bat bug]). Contrary to previous reports, bed bugs were found to be reproductively compatible at both the intra- and inter-lineage levels, but not at the inter-species level (although three hybrids were produced, one of which developed into an adult). Lineage- and species-specific aggregation fidelity was only detected in 8% (4 out of 48) of the aggregation fidelity assays run. These results indicate that under laboratory conditions, host-associated lineages of bed bugs are reproductively compatible, and aggregation pheromones are not capable of preventing gene flow between lineages.}, number={1}, journal={Scientific Reports}, publisher={Springer Science and Business Media LLC}, author={DeVries, Zachary and Mick, Russell and Balvín, Ondřej and Schal, Coby}, year={2017}, month={Oct} }
 @article{campbell_miller_devries_appel_2017, title={Water loss and metabolic activity in bed bug eggs (Cimex lectularius)}, volume={42}, ISSN={["1365-3032"]}, DOI={10.1111/phen.12204}, abstractNote={AbstractFew studies have evaluated water loss and respiratory activity of insect eggs, particularly insects that are known to live within indoor environments. The present study quantifies water loss and respiratory activity for the eggs of a re‐emerging indoor pest of human environments Cimex lectularius (L.). Water loss is measured gravimetrically and calculated as a function of chorion permeability. For these studies, bed bug eggs are placed at 0% relative humidity and repeatedly weighed over 48 h. Temperature effects and bed bug strain differences on the standard metabolic rate (SMR) and respiratory quotient are measured using closed system respirometry. The SMR (; mL g−1 h−1) is measured for two field strain bed bugs and compared with a laboratory strain held at one temperature (25 °C). The standard metabolic rate is measured for Harlan (laboratory) strain bed bug eggs at six different temperatures (15, 20, 25, 30, 35 and 39 °C). Total water loss is not significantly different between all three strains. However, water loss across the chorion (chorion permeability) is significantly different between the Harlan laboratory strain and the two field collected strains. Standard metabolic rates for Harlan (laboratory) strain bed bug eggs increase with temperatures from 15 to 35 °C but decline at 39 °C. Overall, the Harlan bed bug eggs have the largest standard metabolic rates (0.18 ± 0.05 mL g−1 h−1) compared with the Epic Center strain eggs (0.14 ± 0.03 mL g−1 h−1) and Richmond strain eggs (0.16 ± 0.04 mL g−1 h−1), although this difference is not significant.}, number={4}, journal={PHYSIOLOGICAL ENTOMOLOGY}, author={Campbell, Brittany E. and Miller, Dini M. and Devries, Zachary C. and Appel, Arthur G.}, year={2017}, month={Dec}, pages={355–361} }
 @article{balvín_bartonička_pilařová_devries_schal_2016, title={Discrimination between lineage-specific shelters by bat- and human-associated bed bugs does not constitute a stable reproductive barrier}, volume={116}, ISSN={0932-0113 1432-1955}, url={http://dx.doi.org/10.1007/s00436-016-5284-y}, DOI={10.1007/s00436-016-5284-y}, abstractNote={The common bed bug Cimex lectularius, has been recently shown to constitute two host races, which are likely in the course of incipient speciation. The human-associated lineage splits from the ancestral bat-associated species deep in the history of modern humans, likely even prior to the Neolithic Period and establishment of the first permanent human settlements. Hybridization experiments between these two lineages show that post-mating reproductive barriers are incomplete due to local variation. As mating takes place in off-host refugia marked by aggregation semiochemicals, the present investigation tested the hypothesis that bed bugs use these semiochemicals to differentiate between refugia marked by bat- and human-associated bed bugs; this would constitute a pre-copulation isolation mechanism. The preference for lineage-specific odors was tested using artificial shelters conditioned by a group of either male or female bed bugs. Adult males were assayed individually in four-choice assays that included two clean unconditioned control shelters. In most assays, bed bugs preferred to rest in conditioned shelters, with no apparent fidelity to shelters conditioned by their specific lineage. However, 51 % of the bat-associated males preferred unconditioned shelters over female-conditioned shelters of either lineage. Thus, bed bugs show no preferences for lineage-specific shelters, strongly suggesting that semiochemicals associated with shelters alone do not function in reproductive isolation.}, number={1}, journal={Parasitology Research}, publisher={Springer Science and Business Media LLC}, author={Balvín, Ondřej and Bartonička, Tomáš and Pilařová, Kateřina and DeVries, Zachary and Schal, Coby}, year={2016}, month={Nov}, pages={237–242} }
 @article{devries_kells_appel_2016, title={Estimating the critical thermal maximum (CTmax) of bed bugs, Cimex lectularius: Comparing thermolimit respirometry with traditional visual methods}, volume={197}, ISSN={["1531-4332"]}, DOI={10.1016/j.cbpa.2016.03.003}, abstractNote={Evaluating the critical thermal maximum (CTmax) in insects has provided a number of challenges. Visual observations of endpoints (onset of spasms, loss of righting response, etc.) can be difficult to measure consistently, especially with smaller insects. To resolve this problem, Lighton and Turner (2004) developed a new technique: thermolimit respirometry (TLR). TLR combines real time measurements of both metabolism (V·CO2) and activity to provide two independent, objective measures of CTmax. However, several questions still remain regarding the precision of TLR and how accurate it is in relation to traditional methods. Therefore, we evaluated CTmax of bed bugs using both traditional (visual) methods and TLR at three important metabolic periods following feeding (1d, 9d, and 21d). Both methods provided similar estimates of CTmax, although traditional methods produced consistently lower values (0.7-1°C lower than TLR). Despite similar levels of precision, TLR provided a more complete profile of thermal tolerance, describing changes in metabolism and activity leading up to the CTmax, not available through traditional methods. In addition, feeding status had a significant effect on bed bug CTmax, with bed bugs starved 9d (45.19[±0.20]°C) having the greatest thermal tolerance, followed by bed bugs starved 1d (44.64[±0.28]°C), and finally bed bugs starved 21d (44.12[±0.28]°C). Accuracy of traditional visual methods in relation to TLR is highly dependent on the selected endpoint; however, when performed correctly, both methods provide precise, accurate, and reliable estimations of CTmax.}, journal={COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY}, author={DeVries, Zachary C. and Kells, Stephen A. and Appel, Arthur G.}, year={2016}, month={Jul}, pages={52–57} }
 @article{devries_mick_schal_2016, title={Feel the heat: activation, orientation and feeding responses of bed bugs to targets at different temperatures}, volume={219}, ISSN={0022-0949 1477-9145}, url={http://dx.doi.org/10.1242/jeb.143487}, DOI={10.1242/jeb.143487}, abstractNote={Host location in bed bugs is poorly understood. Of the primary host-associated cues known to attract bed bugs – CO2, odors, heat – heat has received little attention as an independent stimulus. We evaluated the effects of target temperatures ranging from 23-48°C on bed bug activation, orientation, and feeding. Activation and orientation responses were assessed using a heated target in a circular arena. All targets heated above ambient temperature activated bed bugs (initiated movement) and elicited oriented movement toward the target, with higher temperatures generally resulting in faster activation and orientation. The distance over which bed bugs could orient toward a heat source was measured using a 2-choice T-maze assay. Positive thermotaxis was limited to distances<3 cm. Bed bug feeding responses on an artificial feeding system increased with feeder temperature up to 38°C and 43°C, and declined precipitously at 48°C. In addition, bed bugs responded to the relative difference between ambient and feeder temperatures. These results highlight the wide range of temperatures which elicit activation, orientation, and feeding responses in bed bugs. In contrast, the ability of bed bugs to correctly orient towards a heated target, independently of other cues, is limited to very short distances (< 3 cm). Finally, bed bug feeding is shown to be relative to ambient temperature, not an absolute response to feeder-blood temperature.}, number={23}, journal={The Journal of Experimental Biology}, publisher={The Company of Biologists}, author={DeVries, Zachary C. and Mick, Russell and Schal, Coby}, year={2016}, month={Sep}, pages={3773–3780} }
 @article{devries_appel_2014, title={Effects of temperature on nutrient self-selection in the silverfish Lepisma saccharina}, volume={39}, ISSN={["1365-3032"]}, DOI={10.1111/phen.12064}, abstractNote={AbstractNutrient self‐selection represents an important behaviour that has been measured across many taxa. Despite the amount of research on this phenomenon, few studies report the evaluation of the effects of environmental variables such as temperature on nutrient selection by animals. In the present study, the nutrient selections of the silverfish Lepisma saccharina L. are measured across a range of temperatures (10, 15, 20, 25, 30 and 35 °C) using feeding arenas with three nutrient choices: carbohydrate (sucrose), protein (casein) and fat (lard). An overall preference for carbohydrates is shown across the range of temperatures, followed by protein, and then fat. However, the proportional consumption of each dietary component changes with temperature; the proportional carbohydrate consumption decreases dramatically with increasing temperature (>94% of the diet at 15 °C but <58% at 30 °C), whereas the proportional protein and lipid consumption increases with increasing temperature up to 30 °C. Changes in nutrient selection with temperature may be related to the dietary requirements of the insect at different temperatures.}, number={3}, journal={PHYSIOLOGICAL ENTOMOLOGY}, author={DeVries, Zachary C. and Appel, Arthur G.}, year={2014}, month={Sep}, pages={217–221} }
 @article{devries_kells_appel_2013, title={Standard metabolic rate of the bed bug, Cimex lectularius: Effects of temperature, mass, and life stage}, volume={59}, ISSN={["1879-1611"]}, DOI={10.1016/j.jinsphys.2013.08.012}, abstractNote={Metabolic rates provide important information about the biology of organisms. For ectothermic species such as insects, factors such as temperature and mass heavily influence metabolism, but these effects differ considerably between species. In this study we examined the standard metabolic rate of the bed bug, Cimex lectularius L. We used closed system respirometry and measured both O2 consumption and CO2 production across a range of temperatures (10, 20, 25, 30, 35 °C) and life stages, while also accounting for activity. Temperature had a stronger effect on the mass specific V̇O2 (ml g−1 h−1) of mated males (Q10 = 3.29), mated females (Q10 = 3.19), unmated males (Q10 = 3.09), and nymphs that hatched (first instars, Q10 = 3.05) than on unmated females (Q10 = 2.77) and nymphs that molted (second through fifth instars, Q10 = 2.78). First instars had significantly lower respiratory quotients (RQ) than all other life stages. RQ of all stages was not affected by temperature. V̇O2 (ml h−1) scaled more with mass than values previously reported for other arthropods or that would be predicted by the 3/4-power law. The results are used to understand the biology and ecology of the bed bug.}, number={11}, journal={JOURNAL OF INSECT PHYSIOLOGY}, author={DeVries, Zachary C. and Kells, Stephen A. and Appel, Arthur G.}, year={2013}, month={Nov}, pages={1133–1139} }