Sublethal Effects Of Dinotefuran Enantiosmers On Honeybees Apis Mellifera L.

Honeybees Apis mellifera L.also known as the western bee,which is belonging to the yellow bee species and it is a strong group of honeybees.There are so many bee farmers raising Apis mellifera L.in our countries.Nowadays,many studies were conducted about the toxicity of neonicotinoid insecticides on honeybees.But the third generation of new nicotinic insecticides dinotefuran which have two enantiomers,were rarely studied about its acute toxicity and sublethal effects on honeybees.Therefore,this study determined the acute toxicity and sublethal effects of dinotefuran on Apis mellifera L.and described the difference of the toxicities of dinotefuran two enantiomers on Apis mellifera L.and the safety of the neonicotinoid insecticides on bees.This study is aimed to evaluate safety of pesticide dinotefuran and reduce the potential risk and provide the theoretical basis of the social economic insect honeybee.The main results of this study are as follows:1.The raceme and two enantiomers of dinotefuran have high acute oral toxicity on honeybee,R-dinotefuran have higher acute oral toxicity than rac-dinotefuran,and rac-dinotefuran have higer acute oral toxicity than S-dinotefuran.So R-dinotefuran have higher risk than S-dinotefuran.2.The study of the difference of the sublethal doses of two enantiosmers dinotefuran of the effect on honeybee biochemical indexes.At the concentrations of LC5 or LC20,dinotefuran could promote the activity of carboxylesterase and glutathione S-transferase,the overall of them were as follows:rac-dinotefuran>S-dinotefuran>R-dinotefuran and S-dinotefuran>R-dinotefuran>rac-dinotefuran.But for actylcholin esterase,dinotefuran could inhibite the activity of it,the overall of inhibiting effect of dinotefuran was S-dinotefuran>R-dinotefuran>rac-dinotefuran.The overall of inhibiting effect of dinotefuran on honeybee polyphenol oxidase was rac-dinotefuran>S-dinotefuran>R-dinotefuran.3.The study of the difference of the sublethal doses of two enantiosmers dinotefuran of the effects on honeybee sensitivity of sucrose.At the concentrations of LC5 LC20 or LC30,the inhibition of dinotefuran on honeybee of different doses of sucrose solutions(10%?30%?50%,w/v)responsibility was R-dinotefuran>S-dinotefuran>rac-dinotefuran.4.The study of the difference of the sublethal doses of two enantiosmers dinotefuran of the effects on honeybee learning and memory ability.At the concentrations of LC5 or LC20,the inhibition of dinotefuran on honeybee learning and memory ability was rac-dinotefuran>R-dinotefuran>S-dinotefuran.5.The study of the difference of the sublethal doses of two enantiosmers dinotefuran of the effects on honeybee brain octopamine content.At the concentrations of LC5 or LC20,the concentration of octopamine on honeybee brain was rac-dinotefuran>R-dinotefuran>S-dinotefuran.This study described the significant difference of the toxicities of dinotefuran two enantiomers on honeybees.Oral exposure to sublethal doses of S-dinotefuran had higher negative impact on honeybee learning and memory ability than exposure to R-dinotefuran.