CHRONIC, SUB-LETHAL IMIDACLOPRID EXPOSURE ALTERS LEARNING ACQUISITION AND BRAIN STRUCTURE IN A HONEY BEE MODEL

Honey bees (Apis mellifera) are key pollinators that have been affected by agricultural chemical agents such as the neonicotinoid insecticide imidacloprid. Alterations in sucrose responsiveness, locomotion, and learning due to sublethal exposure to imidacloprid have been suggested by previous research. These changes are hypothesized to be a result of alterations in the honey bee brain resulting from the neurotoxic effects of imidacloprid. Honey bee learning can be studied using the proboscis extension reflex (PER) assay. In this Pavlovian training model, the natural response of honey bees to extend their proboscis upon presentation of a sugar reward is associated with a novel odor. Imidacloprid has been suggested to alter the cognition of honey bees due to a decreased ability to make associations of olfactory and visual cues. In addition, immunohistochemical methods can investigate the changes to honey bee brain structures, linking brain structure to behavioral changes. In this study, we expose honey bees to imidacloprid at field-relevant doses for 1 week before conducting PER assays to measure associative learning as well as processing matched bee brains using immunohistochemical methods to observe structural changes in the primary brain region necessary for associative learning acquisition in insects, the mushroom body.

For more information:  ktjahaj@eckerd.edu