Learning, memory, and sensory perception are impaired by exposure to the organophosphate, ethion, and the insect growth regulator, hexaflumuron, in honey bees (Apis mellifera L.)

Insecticides are a major tool for controlling pest species. Their widespread use results in damage to non-targeted insects, with honey bees particularly at risk. During foraging, honey bees learn and remember floral characteristics that are associated with food. As insect pollinators, honey bees inadvertently contact chemicals which can have multiple negative impacts. The toxicity of two insecticides from different classes, ethion (47.79 mg a.i. L-1) and hexaflumuron (500 mg a.i.L-1), on learning, memory, and sensory perception were evaluated. We found that oral exposure to ethion had adverse effects on learned proboscis extension toward reward-associated odors and colors. In addition, we showed reduced sucrose consumption and sucrose responsiveness after exposure. Hexaflumuron also impaired olfactory learning and memory and decreased responsiveness to sucrose and water. Exposure to sub-lethal concentration of the cholinergic organophosphate insecticide, ethion (47.79 mg a.i. L-1), and the field-recommended concentration of hexaflumuron (500 mg a.i.L-1), significantly impaired behavior involved in foraging. Our results suggest that several behavioral characteristics of honey bees be evaluated when testing an insecticide rather than relying on just one behavioral measure.