氯化锂对意大利蜜蜂基于伸吻反应行为的影响

Effects of lithium chloride on Apis mellifera ligustica(Hymenoptera:Apidae) based on proboscis extension response behavior

【目的】本研究旨在明确25mmol·L^-1氯化锂对蜜蜂蔗糖敏感性、学习和记忆行为的影响,为氯化锂作为杀螨剂应用于蜂业提供参考依据。【方法】利用50%(w/v)糖水溶液在巢门口引蜂,抓取采集糖水的蜜蜂视为采集蜂,随机分为6组对照和处理。鉴于蜜蜂对笼养环境的适应期,室内恒温恒湿箱【(30±1)℃,相对湿度为40%±10%,黑暗】中饲喂30%糖水笼养24 h(每盒50头)后,处理组和对照组分别自由采集含25 mmol·L^-1氯化锂的30%(w/v)糖水和30%(w/v)糖水24 h,6组中的3组用来测试对6种不同浓度糖水的敏感性(0.1%、0.3%、1%、3%、10%、30%),余下3组蜜蜂用来进行气味联想性学习实验;将收集的采集蜂不进行实验室笼养,随机分为对照和处理(35头/组),接受气味联想性学习训练,然后对蜜蜂个体饲喂10μL 30%(w/v)糖水和含25 mmol·L^-1氯化锂的30%(w/v)糖水,2 h后测试蜜蜂记忆。【结果】对照组和处理组在氯化锂处理24 h内死亡率无显著差异(P>0.05);糖水敏感性测试实验中,处理组对低浓度糖水(0.1%-3%)的喙伸反应率高于对照组(0.3%:P<0.05;1%:P<0.01;3%:P<0.001),处理组的蔗糖响应分数(SRS)极显著高于对照组(P<0.01);气味联想性学习实验中,两组的喙伸反应率随训练次数的增加而呈上升趋势,虽然在第二次学习中,对照组的喙伸反应率显著性高于处理组(P<0.05),但两组的学习能力随训练次数增加差异减小,最终趋于一致;2 h记忆行为实验中,处理组的喙伸反应率显著高于对照组(P<0.05)。【结论】结果表明,25 mmol·L^-1氯化锂对蜜蜂无急性致死作用;蜜蜂接触此剂量氯化锂24 h后,蜜蜂对低浓度糖水的敏感性增强,蜜蜂最终学习行为不受影响,但蜜蜂的2 h短期记忆受到积极影响,进而可能利于提高蜜蜂采集行为。

[Objectives] Ziegelmann et al.found that 25 mmol·L^-1 lithium chloride had an effective mite removal rate as high as 96%and suggested that lithium chloride was a highly efficient substance for mite removal.This study aims to investigate the effects of 25 mmol·L^-1 lithium chloride on the sucrose sensitivity,learning and memory of honeybees,and provide a reference for the application of lithium chloride as an acaricide for honeybees.[Methods]We used 50%(w/v)sugar water to draw honeybees to the hive entrance.Honeybees foraging for sugar water were caught and considered to be foragers.We randomly divided these honeybees into five treatment groups and one control.In view of the acclimation period of honeybees to a cage environment,control and treatment groups were both fed 30%(w/v)sugar water ad libitum in an incubator at constant temperature and humidity[(30±1)℃,relative humidity 40%±10%,dark]for 24 h(50 bees per box),then fed 30%(w/v)sugar water ad libitum and 30%(w/v)sugar water containing 25 mmol·L^-1 lithium chloride ad libitum for 24 h,respectively.Three of the six groups were used to test sensitivity to six different sugar water concentrations(0.1%,0.3%,1%,3%,10% and 30%),the remaining three groups were used for olfactory-associative learning experiments.Captured foragers were not kept in cages in the laboratory.We randomly divided these bees into control and treatment groups(35 bees per group),both of which received odor-associative learning training.After this bees in both groups were fed 10μL 30%(w/v)sugar water and 10μL 30%(w/v)sugar water containing 25 mM lithium chloride.We tested bees’memory after 2 h,with three replicates.[Results]There was no significant difference in mortality between control and treatment groups within 24 h of lithium chloride treatment(P>0.05).In the sugar water sensitivity test,the proboscis extension response rate for low concentration sugar water(0.1%-3%)was higher in the treatment group than in the control group(0.3%:P<0.05;1%:P<0.01;3%:P<0.001).The sucrose response scores(SRS)of the treatment group were also significantly higher than those of the control group(P<0.01).In the olfactory associative learning experiment,the proboscis extension response rate of the two groups increased with training time.The proboscis extension response rate of the control group was significantly higher than that of treatment group(P<0.05)in the second learning test,but the difference in learning ability between the two groups decreased with training frequency,eventually becoming similar.In the 2 h memory experiment,the proboscis extension response rate of the treatment group was significantly higher than that of the control group(P<0.05).[Conclusion]25 mmol·L^-1 lithium chloride has no acute lethal effect on honeybees.Exposing honeybees to this concentration of lithium chloride for 24 h enhanced their sensitivity to low concentrations of sugar water.Exposure to 25 mmol·L^-1 lithium chloride did not affect the learning behavior of honeybees,but did affect their 2 h short-term memory,which may improve their foraging behavior.