@article{mcafee_metz_milone_foster_tarpy_2022, title={Drone honey bees are disproportionately sensitive to abiotic stressors despite expressing high levels of stress response proteins}, volume={5}, ISSN={["2399-3642"]}, DOI={10.1038/s42003-022-03092-7}, abstractNote={Drone honey bees (Apis mellifera) are the obligate sexual partners of queens, and the availability of healthy, high-quality drones directly affects a queen's fertility and productivity. Yet, our understanding of how stressors affect adult drone fertility, survival, and physiology is presently limited. Here, we investigated sex biases in susceptibility to abiotic stressors (cold stress, topical imidacloprid exposure, and topical exposure to a realistic cocktail of pesticides). We found that drones (haploid males) were more sensitive to cold and imidacloprid exposure than workers (sterile, diploid females), but the cocktail was not toxic at the concentrations tested. We corroborated this lack of cocktail toxicity with in-hive exposures via pollen feeding. We then used quantitative proteomics to investigate protein expression profiles in the hemolymph of topically exposed workers and drones, and found that 34 proteins were differentially expressed in exposed drones relative to controls, but none were differentially expressed in exposed workers. Contrary to our hypothesis, we show that drones express surprisingly high baseline levels of putative stress response proteins relative to workers. This suggests that drones' stress tolerance systems are fundamentally rewired relative to workers, and susceptibility to stress depends on more than simply gene dose or allelic diversity.}, number={1}, journal={COMMUNICATIONS BIOLOGY}, author={McAfee, Alison and Metz, Bradley N. and Milone, Joseph P. and Foster, Leonard J. and Tarpy, David R.}, year={2022}, month={Feb} }
 @article{milone_chakrabarti_sagili_tarpy_2021, title={Colony-level pesticide exposure affects honey bee (Apis mellifera L.) royal jelly production and nutritional composition}, volume={263}, ISSN={["1879-1298"]}, DOI={10.1016/j.chemosphere.2020.128183}, abstractNote={Honey bees provision glandular secretions in the form of royal jelly as larval nourishment to developing queens. Exposure to chemicals and nutritional conditions can influence queen development and thus impact colony fitness. Previous research reports that royal jelly remains pesticide-free during colony-level exposure and that chemical residues are buffered by the nurse bees. However, the impacts of pesticides can also manifest in quality and quantity of royal jelly produced by nurse bees. Here, we tested how colony exposure to a multi-pesticide pollen treatment influences the amount of royal jelly provisioned per queen and the additional impacts on royal jelly nutritional quality. We observed differences in the metabolome, proteome, and phytosterol compositions of royal jelly synthesized by nurse bees from multi-pesticide exposed colonies, including significant reductions of key nutrients such as 24-methylenecholesterol, major royal jelly proteins, and 10-hydroxy-2-decenoic acid. Additionally, quantity of royal jelly provisioned per queen was lower in colonies exposed to pesticides, but this effect was colony-dependent. Pesticide treatment had a greater impact on royal jelly nutritional composition than the weight of royal jelly provisioned per queen cell. These novel findings highlight the indirect effects of pesticide exposure on queen developmental nutrition and allude to social consequences of nurse bee glandular degeneration.}, journal={CHEMOSPHERE}, author={Milone, Joseph P. and Chakrabarti, Priyadarshini and Sagili, Ramesh R. and Tarpy, David R.}, year={2021}, month={Jan} }
 @article{mcafee_milone_metz_mcdermott_foster_tarpy_2021, title={Honey bee queen health is unaffected by contact exposure to pesticides commonly found in beeswax}, volume={11}, ISSN={["2045-2322"]}, DOI={10.1038/s41598-021-94554-1}, abstractNote={Abstract Honey bee queen health is crucial for colony health and productivity, and pesticides have been previously associated with queen loss and premature supersedure. Prior research has investigated the effects of indirect pesticide exposure on queens via workers, as well as direct effects on queens during development. However, as adults, queens are in constant contact with wax as they walk on comb and lay eggs; therefore, direct pesticide contact with adult queens is a relevant but seldom investigated exposure route. Here, we conducted laboratory and field experiments to investigate the impacts of topical pesticide exposure on adult queens. We tested six pesticides commonly found in wax: coumaphos, tau-fluvalinate, atrazine, 2,4-DMPF, chlorpyriphos, chlorothalonil, and a cocktail of all six, each administered at 1, 4, 8, 16, and 32 times the concentrations typically found in wax. We found no effect of any treatment on queen mass, sperm viability, or fat body protein expression. In a field trial testing queen topical exposure of a pesticide cocktail, we found no impact on egg-laying pattern, queen mass, emergence mass of daughter workers, and no proteins in the spermathecal fluid were differentially expressed. These experiments consistently show that pesticides commonly found in wax have no direct impact on queen performance, reproduction, or quality metrics at the doses tested. We suggest that previously reported associations between high levels of pesticide residues in wax and queen failure are most likely driven by indirect effects of worker exposure (either through wax or other hive products) on queen care or queen perception.}, number={1}, journal={SCIENTIFIC REPORTS}, author={McAfee, Alison and Milone, Joseph P. and Metz, Bradley and McDermott, Erin and Foster, Leonard J. and Tarpy, David R.}, year={2021}, month={Jul} }
 @article{mcafee_milone_chapman_foster_pettis_tarpy_2020, title={Candidate stress biomarkers for queen failure diagnostics}, volume={21}, ISSN={["1471-2164"]}, DOI={10.1186/s12864-020-06992-2}, abstractNote={Abstract Background Queen failure is a persistent problem in beekeeping operations, but in the absence of overt symptoms it is often difficult, if not impossible, to ascertain the root cause. Stressors like heat-shock, cold-shock, and sublethal pesticide exposure can reduce stored sperm viability and lead to cryptic queen failure. Previously, we suggested candidate protein markers indicating heat-shock in queens. Here, we further investigate these heat-shock markers and test new stressors to identify additional candidate protein markers. Results We found that heat-shocking queens for upwards of 1 h at 40 °C was necessary to induce significant changes in the two strongest candidate heat-shock markers, and that relative humidity significantly influenced the degree of activation. In blind heat-shock experiments, we tested the efficiency of these markers at assigning queens to their respective treatment groups and found that one marker was sufficient to correctly assign queens 75% of the time. Finally, we compared cold-shocked queens at 4 °C and pesticide-exposed queens to controls to identify candidate markers for these additional stressors, and compared relative abundances of all markers to queens designated as ‘healthy’ and ‘failing’ by beekeepers. Queens that failed in the field had higher expression of both heat-shock and pesticide protein markers, but not cold-shock markers. Conclusions This work offers some of the first steps towards developing molecular diagnostic tools to aid in determining cryptic causes of queen failure. Further work will be necessary to determine how long after the stress event a marker’s expression remains elevated, and how accurate these markers will be for field diagnoses.}, number={1}, journal={BMC GENOMICS}, author={McAfee, Alison and Milone, Joseph and Chapman, Abigail and Foster, Leonard J. and Pettis, Jeffery S. and Tarpy, David R.}, year={2020}, month={Aug} }
 @article{milone_rinkevich_mcafee_foster_tarpy_2020, title={Differences in larval pesticide tolerance and esterase activity across honey bee (Apis mellifera) stocks}, volume={206}, ISSN={["1090-2414"]}, DOI={10.1016/j.ecoenv.2020.111213}, abstractNote={Honey bee populations in North America are an amalgamation of diverse progenitor ecotypes experiencing varying levels of artificial selection. Genetic differences between populations can result in variable susceptibility towards environmental stressors, and here we compared pesticide tolerances across breeding stocks using a mixture of seven pesticides frequently found in colonies providing pollination services. We administered the pesticide mixture chronically to in vitro reared larvae at four concentrations of increasing Hazard Quotient (HQ, or cumulative toxicity) and measured mortality during larval development. We found that different stocks had significantly different tolerances to our pesticide mixture as indicated by their median lethal toxicity (HQ50). The intensively selected Pol-Line stock exhibited the greatest pesticide sensitivity while Old World (progenitor) and putatively feral stocks were the most pesticide-tolerant. Furthermore, we found that activity of the detoxification enzyme esterase was positively correlated with pesticide tolerance when measured using two different substrate standards, and confirmed that larvae from the Pol-Line stock had generally lower esterase activity. Consistent with an increased pesticide tolerance, the Old World and putatively feral stocks had higher esterase activities. However, esterases and other detoxification enzymes (CYP450s and GSTs) were found in similar abundances across stocks, suggesting that the differences in enzyme activity we observed might arise from stock-specific single nucleotide polymorphisms or post-translational modifications causing qualitative variation in enzyme activity. These results suggest that selective breeding may inadvertently increase honey bees’ sensitivity to pesticides, whereas unselected, putatively feral and Old World stocks have larvae that are more tolerant.}, journal={ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY}, author={Milone, Joseph P. and Rinkevich, Frank D. and McAfee, Alison and Foster, Leonard J. and Tarpy, David R.}, year={2020}, month={Dec} }
 @article{mcafee_chapman_higo_underwood_milone_foster_guarna_tarpy_pettis_2020, title={Vulnerability of honey bee queens to heat-induced loss of fertility}, volume={3}, ISSN={["2398-9629"]}, DOI={10.1038/s41893-020-0493-x}, abstractNote={All species need to reproduce to maintain viable populations, but heat stress kills sperm cells across the animal kingdom and rising frequencies of heat waves are a threat to biodiversity. Honey bees (Apis mellifera) are globally distributed microlivestock; therefore, they could serve as environmental biomonitors for fertility losses. Here, we found that queens have two potential routes of temperature-stress exposure: within colonies and during routine shipping. Our data suggest that temperatures of 15–38 °C are safe for queens at a tolerance threshold of 11.5% loss of sperm viability, which is the viability difference associated with queen failure in the field. Heat shock activates expression of specific stress-response proteins in the spermatheca, which could serve as molecular biomarkers (indicators) for heat stress. This protein fingerprint may eventually enable surveys for the prevalence of heat-induced loss of sperm viability in diverse landscapes as part of a biomonitoring programme. Heat waves can pose a threat to biodiversity as heat stress kills sperm cells across the animal kingdom. Here, honey bee queens are found to be vulnerable to temperature changes and the specific stress-response proteins activated in the spermatheca are discussed as potential indicators of heat stress.}, number={5}, journal={NATURE SUSTAINABILITY}, author={McAfee, Alison and Chapman, Abigail and Higo, Heather and Underwood, Robyn and Milone, Joseph and Foster, Leonard J. and Guarna, M. Marta and Tarpy, David R. and Pettis, Jeffery S.}, year={2020}, month={May}, pages={367–376} }