Distinct molecular impact patterns of abamectin on Apis mellifera ligustica and Apis cerana cerana

The effects of insecticides on bee health are a topic of intensive research. Although abamectin is toxic to bees, the molecular impact of abamectin needs to be clarified. Here, we found that Apis cerana cerana exhibited a higher mortality rate when exposed to abamectin than Apis mellifera ligustica. In addition, A. cerana cerana had markedly higher numbers of differentially expressed genes (DEGs), differentially expressed proteins (DEPs) and differentially expressed metabolites (DEMs) than A. mellifera ligustica during exposure to abamectin. These results indicate that abamectin exposure exerts stronger effects on A. cerana cerana than on A. mellifera ligustica. In addition, six DEGs, two DEPs and two DEMs overlapped between the two bee species under abamectin exposure; however, some genes or proteins from the zinc finger protein, superoxide dismutase and peroxiredoxin families and the energy metabolism pathway were only unregulated in A. cerana cerana, which indicates a significant difference in the impact of abamectin on the two bee species. Despite these differences, several of the same gene families, such as heat shock proteins, cytochrome P450, odorant-binding proteins and cuticle proteins, and pathways, including the carbohydrate metabolism, immune system, lipid metabolism, amino acid metabolism, sensory system, locomotion and development pathways, were influenced by abamectin exposure in both A. cerana cerana and A. mellifera ligustica. Together, our results indicate that abamectin causes adverse effects on bees and thus poses a risk to bee populations and that abamectin exposure affects A. cerana cerana more strongly than A. mellifera ligustica. These findings improve our understanding of the behavioural and physiological effects of abamectin on bees.