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ARS Home » Southeast Area » Baton Rouge, Louisiana » Honey Bee Lab » Research » Publications at this Location » Publication #399663
Research Project: Using Genetics to Improve the Breeding and Health of Honey Bees

Location: Honey Bee Breeding, Genetics, and Physiology Research

Title: Transcriptomic analysis of the honey bee (Apis mellifera) queen brain reveals that gene expression is affected by pesticide exposure during development

Author
item DICKEY, MYRA - Texas A&M University
item Walsh, Elizabeth
item SHEPHERD, TONYA - Texas A&M University
item MEDINA, RAUL - Texas A&M University
item TARONE, AARON - Texas A&M University
item RANGEL, JULIANA - Texas A&M University

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/12/2023
Publication Date: 4/27/2023
Citation: Dickey, M., Walsh, E.M., Shepherd, T.F., Medina, R.F., Tarone, A., Rangel, J. 2023. Transcriptomic analysis of the honey bee (Apis mellifera) queen brain reveals that gene expression is affected by pesticide exposure during development. PLOS ONE. 18(4):e0284929. https://doi.org/10.1371/journal.pone.0284929.
DOI: https://doi.org/10.1371/journal.pone.0284929

Interpretive Summary: Honey bee queens are exposed to pesticides before they reach adulthood through contact with beeswax during development (i.e., during egg, larvae, and pupal stages). We examined if field-relevant levels and combinations of pesticide exposure changed the way genes in the honey bee queen are expressed. Differences in gene expression can indicate larger differences in organism health and lifespan. We found that there are changes in genetic expression based on the rearing environment that the queens matured in. In particular, queens reared in an environment with the pesticide amitraz have different gene expression in their brains than queens reared in pesticide-free beeswax.

Technical Abstract: Honey bees (Apis mellifera) play a pivotal role in agricultural production worldwide, primarily through the provision of pollination services. But despite their importance, honey bee health continues to be threatened by many factors, including parasitization by the mite Varroa destructor, poor queen quality, and pesticide exposure. Accumulation of pesticides in the hive’s comb matrix over time inevitably leads to the exposure of developing brood, including queens, to wax contaminated with several compounds. Here, we characterized the brain transcriptome of queens that were reared in wax contaminated with pesticides commonly found in commercial beekeeping operations including either (a) a combination of 204,000 ppb of tau-fluvalinate and 91,900 ppb of coumaphos (“FC” group), (b) a combination of 9,800 ppb of chlorpyrifos and 53,700 ppb of chlorothalonil (“CC” group), or (c) 43,000 ppb of Amitraz (“A” group). Control queens were reared in pesticide-free wax. Adult queens were allowed to mate naturally before being dissected. RNA isolated from brain tissue from three individuals per treatment group was sequenced using three technical replicates per queen. Using a cutoff log2 fold-change value of 1.5, we identified 247 differentially expressed genes (DEGs) in the FC group, 244 in the CC treatment group, and 668 in the A group, when comparing each group to the control. This is the first study to examine the sublethal effects of pesticides commonly used found in wax (particularly amitraz) on the queen’s brain transcriptome. Future studies should further explore the sublethal effects of pesticide exposure on the overall health of honey bee queens.