Effect of sublethal doses of imidacloprid on Acetylcholinesterase activity in Apis mellifera
Author of the article:JIN San-Xing** MENG Li-Feng DIAO Qing-Yun***
Author's Workplace：Key Laboratory of Pollinating Insect Biology of Ministry of Agriculture, Institute of Apicultural Research, Chinese Academy of Agricultural Science, Beijing 100093, China
Key Words：imidacloprid, honeybee, acetylcholinesterase, sub lethal effect
Abstract：[Objectives] To determine the median lethal concentration of imidacloprid and explore the sublethal effect of imidacloprid on acetylcholinesterase (AChE) in Apis mellifera. [Methods] The toxicity of imidacloprid was determined by feeding trials, topical application and the residual film method. AChE activity and the relative expression of acetylcholinesterase mRNA genes (Ace1 and Ace2) in the head of A. mellifera were measured after exposure to different concentrations of imidacloprid after different periods of time. [Results] LC50 values determined by the three methods were 7.15 mg/L、0.078 ng/bee and 51 ng/cm2, respectively. Imidacloprid inhibited AChE activity within 24 h. The enzymatic activity of AChE was volatile with increasing pesticide concentration, fluctuating with the dose and period of imidacloprid exposure. mRNA expression of the Ace1 and Ace2 genes was induced within 24 h, but not after 1 h, 2 h and 16 h exposure. [Conclusion] The results show that the effect of imidacloprid on AChE depends on both the period of exposure and dosage. The AChE activity in the heads of honeybees may be inhibited by sub lethal doses of imidacloprid, but the induced mRNA expression patterns of Ace1 and Ace2 was inconsistent with AChE activity.