Neonicotinoid pesticides affect how Asian honeybees learn to sniff out flowers, suggests a study in Scientific Reports this week. Impairing this behaviour may reduce feeding, which could have negative impacts on bee colony health.
Research has indicated that sub-lethal doses of neonicotinoid pesticides may disrupt bee health and foraging abilities, which could have knock-on effects for the key pollination services that they provide. Studies have shown that, in the European honeybee (Apis mellifera), sub-lethal doses of neonicotinoids can impair olfactory learning ? the process that allows bees to associate floral odours with nectar rewards, thereby facilitating foraging and pollination. Ken Tan and colleagues observe similar effects in the Asian honeybee species, Apis cerana, an important pollinator of agricultural and native Asian plants.
Adult bees exposed to imidacloprid, a neonicotinoid pesticide that is widely used throughout China, displayed reduced longer-term olfactory learning acquisition compared with bees that had not been exposed. In addition, A. cerana larvae exposed to sub-lethal doses of imidacloprid exhibited poorer short-term learning acquisition as adult bees compared with control bees. The results suggest that effects may be more serious for bees exposed as adults, although the reasons for the differences are unclear and warrant further study.