吡虫啉大田使用剂量对意大利蜜蜂工蜂学习和记忆的影响

Effects of field realistic doses of imidacloprid on learning and memory of Apis mellifera ligustica(Hymenoptera:Apidae) workers

【目的】吡虫啉(imidaclorprid)是新烟碱类农药中使用最为广泛的农药种类,作用于蜜蜂脑部的烟碱型乙酰胆碱受体,此外,吡虫啉对蜜蜂生长发育有一定影响。本研究旨在明确吡虫啉大田使用剂量对蜜蜂学习、记忆行为的影响,为探明部分地区蜂群大面积死亡原因提供佐证,也可为该药田间安全使用提供参考。【方法】用油漆笔标记刚出房的1日龄意大利蜜蜂Apis mellifera ligustica工蜂,置于蜂群中8 d后取出,在室内恒温恒湿箱(30±1℃,相对湿度为40%±10%,黑暗)中笼养9 d(每盒50头),处理组自由采集含0.01 ng/μL吡虫啉的30%(w/v)糖水,对照组自由采集含0.01 ng/μL丙酮的30%(w/v)糖水。使用自制的蜜蜂气味学习设备,在3次配对的柠檬气味刺激和糖水刺激训练基础上,对18日龄蜜蜂进行气味联想性学习和记忆实验。【结果】处理组和对照组蜜蜂在为期9 d的饲喂过程中的死亡率无显著差异(P>0.05)。在3次气味联想性学习实验中,与对照组相比,处理组蜜蜂在第2和第3次实验中学习能力显著降低(P<0.01),而在第1次实验中无差异[喙伸反应率(PER)%=0];24 h后,处理组蜜蜂的喙伸反应率与对照组无显著差异(P>0.05)。【结论】结果表明,0.01 ng/μL吡虫啉不会导致蜜蜂急性死亡;在此剂量吡虫啉作用下,蜜蜂的24 h长期记忆虽不受影响,但学习能力显著受到抑制,进而可能对蜜蜂的采集行为等产生不利影响。

[ Aim ] Imidaclorprid is the most widely used pesticide among neonicotinoid pesticides and acts on the brain＇ s nicotinic acetylcholine receptor of honey bees. In addition, imidaclorprid interferes with the growth and development of honey bees. This study aims to clarify the effects of imidacloprid at field realistic doses on learning and memory of honey bees, so as to provide evidence for the prediction of the widespread death of colonies in some areas and reference for the safe use of neonicotinoid pesticide in the field. [ Methods ] Newly emerged 1-day-old bees （Apis mellifera ligustica） were marked by paint marker. They were kept in the colony for 8 d, and then were reared within boxes （50 individuals/box） in an incubator with constant temperature and humidity （30±1℃, relative humidity 40%±10%, dark） for 9 d. Meanwhile, the treatment group fed 30% （w/v） syrup containing 0.01 ng/μL of imidacloprid ad libitum, while the control group fed 30% （w/v） syrup containing 0.01 ng/μL of acetone ad libitum. Following being trained with three paired stimulations （lemon odor paired with sucrose stimulation ） performed using a customized device, the 18-day-old bees were used for the olfactory associative learning and memory experiments. [ Results ] There was no significant difference in the mortality between the treatment group and the control group during the 9-day feeding period （P 〉 0.05 ）. In the three olfactory associative learning experiments, the learning ability of bees of the treatment group in the 2nd and 3rd experiments was significantly reduced （ P 〈 0.01 ） compared with the control group, but there was no difference in the 1 st experiment [ proboscis extension response （PER） % = 0 ]. After 24 h, the proboscis extension reflex rate was not significantly different between the treatment and control groups （P 〉 0.05 ）. [ Conclusion ] The results demonstrate that 0.01 ng/μL imidacloprid does not cause acute death of honey bees. This dose of imidacloprid does not affect the 24 h long-term memory of honey bees, but impairs learning ability of honey bees significantly and may even adversely affect the foraging behavior of honey bees.