Dietary lipids shape honey bee (Apis mellifera) feeding and resilience to pesticide stress

Abstract

Pesticides are important for crop production but can have negative impacts on beneficial insects such as pollinators. In insects, physiological lipid stores may serve to sequester pesticides, while pesticide metabolism and detoxification often involve fatty acid pathways. Previous studies in Apis mellifera found that honey bees fed pollen with a specific protein-to-lipid ratio had improved survival when exposed to an insecticide. Here, we comprehensively investigate whether and how the type of dietary fat influences survival, energy reserves, and enzymatic biomarkers, following exposure to an organophosphate insecticide, chlorpyrifos. Newly emerged bees were fed protein-based diets enriched with either saturated (SFA), monounsaturated (MUFA), or polyunsaturated fatty acids (PUFA) for 5 days and then exposed orally to chlorpyrifos (at LC₅₀). Bees fed MUFA and PUFA diets consumed significantly more food than those fed SFA-supplemented diet, indicating a clear preference for unsaturated fats. However, under chlorpyrifos exposure, only PUFA-fed bees exhibited significantly higher survival rates, and also maintained greater lipid reserves and acetylcholine esterase activity compared to SFA- and MUFA-fed groups. These results suggest that PUFA-enriched diets may mitigate pesticide toxicity by preserving neural enzyme function and energy homeostasis. No significant changes in glutathione-S-transferase activity were observed across treatments, suggesting limited dietary modulation of this detoxification pathway. Collectively, our findings demonstrate that dietary fatty acid composition influences honey bee physiological resilience to chlorpyrifos and highlight the potential for PUFA-based nutritional interventions or the design of pollinator habitats, to improve resilience to pesticides.