Effects of sublethal doses of insecticides on the olfactory sensitivity of the honeybee（Apis mellifera ligustica）

Key Words：Apis mellifera ligustica, deltamethrin, imidacloprid, proboscis extension reflex (PER), olfactory sensation, sublethal dose

Abstract：       Previous studies have shown that observations of the proboscis extension reflex (PER) are of interest for assessing the behavioral effects of insecticides on the honeybee.In the present study, the effects of sublethal doses (LD₅₀/100—LD₅₀/10) of deltamethrin and imidacloprid on the olfactory sensitivity of honeybees (Apis mellifera ligustica L.) were determined under controlled laboratory conditions using a conditioned PER assay.After oral consumption, deltamethrin reduced both sensitivity to antennal stimulation by sucrose solutions and the waterinduced proboscis extension reflex at doses of 5 ng/bee and 10 ng/bee.Unlike deltamethrin, imidacloprid had no effect in olfactory sensitivity assays but increased the waterinduced proboscis extension reflex.