Honey bee plays an important role in pollinating plants. Recently, however, declines in honey bee populations have been reported in many countries, and pesticides have been pointed out as one of the factors contributing to honey bee loss. To determine the effects of pesticides on honey bee behavior, we investigated the homing ability of honey bee exposed to four pesticides (acetamiprid, imidacloprid, fenitrothion, and carbaryl). In addition, the changes in expression levels of genes associated with ‘learning and memory’ (cGMP-dependent protein kinase foraging, Kruppel homolog 1, Adenlyate cyclase 3, Early growth response protein 1, Hormone receptor 38) were examined after pesticide treatment in forager bee. The four pesticides tested in this study generally reduced the homing ability of foragers. In the examination of gene expression, learning and memory-related genes were induced by the exposure to acetamiprid, imidacloprid, and carbaryl, whereas fenitrothion decreased the expression of these genes in honey bee. Although further studies are needed, this suggests that pesticides may have negative effects on honey bee behavior and behavior-related gene expression.

Pesticides are indispensable in contemporary agriculture but are mainly attributed to honey bee population decline. In order to understand the approximate physiological response to pesticides, honey bees were exposed to seven pesticides (Acetamiprid, Imidacloprid, Flupyradifurone, Carbaryl, Fenitrothion, Amitraz, and Bifenthrin), and expression changes of the genes categorized into four physiological functions (insecticide targets, immune-, detoxification-, and reactive oxygen species response-related gene) were analyzed in the head and abdomen of honey bee exposed to pesticides using quantitative PCR. Based on the heat map analysis, immune-related genes seem to be more up-regulated by pesticide exposure in head than abdomen. Among detoxification genes, only cytochrome P450 families were up-regulated in head. Interestingly, regardless of the insecticide target, expressions of Nicotinic acetylcholine receptor beta 1 and Acetylcholinesterase 1 were notably induced by pesticide exposure in head. Heat map analysis expressing the transcription profiles of various genes in the head and abdomen of the honey bee exposed to various pesticides can be used to diagnose pesticide damage in honey bees in the future.