Risks and underling mechanisms of sulfoxaflor exposure in honey bees (Apis mellifera): Physiology and behavior...

As the most widely used pesticides, the adverse effects of neonicotinoid insecticides to honeybees have been proven. This study assessed the exposure risks of Sulfoxaflor (Sul), an alternative of traditional neonicotinoids, to honey bee (Apis mellifera) workers and clarified its mechanism through gut microbiota and metabolomics analysis. The results revealed a high acute toxicity of Sul to bees with a 48-LD₅₀ of 239 ng/bee via oral exposure. Chronic exposure to sublethal concentrations of Sul (1, 10, and 100 μg/L) over 10 days significantly decreased the sucrose responsiveness, olfactory sensitivity, and CO₂ respiration rates of honeybees. Furthermore, sublethal exposure to Sul elicited distinct immunomodulatory, detoxification, and antioxidation responses in the midgut, as well as metabolic dysregulation. However, no substantial alterations in gut microbial composition or α/β diversity was identified. These findings suggest that sublethal concentrations of Sul do not affect bee survival in a short time, however, they do induce multifaceted sublethal effects and disrupt intestinal physiology and metabolic homeostasis. Consequently, these effects pose ecological risks to honey bees. It is imperative that future research should comprehensively consider various exposure risks of insecticides, prioritize the identification of novel biomarkers to delineate their adverse mechanisms in organisms, particularly pollinating insects.