UC San Diego

Much attention on honey bee declines has focused on the sublethal effects the pesticide, imidacloprid, has on honey bee behavior. How it affects individual foragers and their preference for nectar or their ability to navigate to communicated food sources is unknown. We use the proboscis extension reflex (PER) assay to test an individual's response threshold. Bees treated with the pesticide have higher response thresholds and respond less often to high concentrations of sucrose than control bees. Preliminary trials also show negative effects of a forager's ability to communicate to other nest mates for sweet sugar resources. In a separate experiment, using tunnels to provide optic flow, preliminary data suggest that bees treated with sublethal doses of imidacloprid travel shorter distances than control bees to a trained location. The increased preference for sweeter sucrose concentrations, reduced communication performance, and navigational inefficiency may contribute to a colony's decline