Interactive effects of diet quality, pesticide exposure, and virus infection in honey bees

Honey bees maintained in agricultural landscapes frequently experience the adverse effects of sublethal pesticide exposure, virus infection, and poor forage, but the interactions between these factors remain complex and highly variable. To better understand these stressor dynamics, I performed a series of high-throughput bioassays measuring the survivorship of adult honey bee workers when exposed to different combinations of diet types, pesticides (chlorpyrifos, thiamethoxam, and lambda-cyhalothrin), and virus (Israeli acute paralysis virus) infection. Our results showed that diet type can significantly influence survivorship response, but is dependent on pesticide identity and presence of virus. Pollen consumption can improve survival when bees are exposed to viruses and field-relevant pesticide doses and can even be involved with inducing hormetic responses to chlorpyrifos ingestion, but these effects are not universal across all pesticides. Eventual examinations of viral titers and immune gene expression should provide better insight regarding which aspect of the honey bees’ physiology these stressors are affecting, thereby improving understanding of basic bee biology, and helping to inform bee health management decisions.