Diet Quality Modulates Mortality and Vitellogenin Expression in Honey Bees Under Pesticide Stress

Adequate nutrition is essential for honey bees to withstand environmental stressors, though the efficacy of artificial diets remains largely unknown. This study examines whether balanced nutrition, particularly artificial substitutes, can mitigate the harmful effects of prevalent hive contaminants, specifically the pesticides fluvalinate and chlorpyrifos. Bees were fed a poor carbohydrate diet, pollen, or a substitute, with or without the pesticide mixture, and their lifespan, midgut proteolytic activity, detoxification, and antioxidant responses were measured. Results showed protein-rich diets, pollen, and the substitute significantly mitigated the toxicity effects on lifespan, with mortality rates comparable to normal conditions. In contrast, bees on carbohydrates experienced significantly higher mortality under pesticide stress. At the molecular level, toxicity neither affected midgut proteolytic activity nor induced transcription of detoxification enzymes (CYP9Q2 and CYP9Q3) or antioxidant enzymes (catalase). However, vitellogenin expression reflected mortality patterns, being repressed under carbohydrates while remaining stable under rich diets despite chemical toxicity. This suggests the protective effect of a rich diet may involve vitellogenin, reducing oxidative stress and supporting immunity and longevity. These findings underscore the importance of high-quality nutrition in boosting stress tolerance and support alternative feeding strategies in colony management when pollen quality is poor or during shortages.