The Effects Of Pesticides On Activity Of Detoxification Enzymes In Apis Cerana Cerana

As the typical example of neonicotine and pyrethroid,imidacloprid and fluvalinate affected the recognition behavior,pollination behavior,growth and development. Apis cerana cerana was more sensitive to pesticide than Apis mellifera, while there was little research about Apis cerana cerana toxicological characteristic. The enzymatic activities when the bee fed or contacted with different concentration of imidacloprid and fluvalinate were researched in this article.The honeybee transcriptom expression at 1h、8h and 16 h after feeding LC5 dose of imidacloprid was also demonstrated in the paper.Under laboratory condition, the feeding and residual film method were used to determine the toxicity of imidaclopridand and fluvalinateon to Apis cerana cerana.The value of LC50 was 3.044 ppm and 0.683 ppm, 177.314 ppm and 7.024 ppm separately. With the same concentration, there were significant differences between feeding and residual film methods. The enzymatic activity of P450/CarE/GSTs fluctuated when honeybee were treated with LC5 dose of imidacloprid. P450 and CarE got a peak activity at 4 h(1.44 and 1.27 times as CK), meanwhile GSTs achieved the highest activity at 12 h(1.21 times as CK) with feeding method; P450 and GSTs were inhibited with a nadir activity at 4h and 12h(all 0.59 times as CK), but CarE was induced at 16 h(1.4 times as CK). When honeybee ate LC5 dose of fluvalinate, activity of P450 reduced significantly, then increased, got a peak point at 16 h(1.28 times as CK). The activity of CarE gradually reduced as time extending, which was very low at 24 h(0.78 times as CK). The activity of GSTs which was a little higher than CK, had no significant effect. All the three detoxification enzymes were inhibited after honeybee contacted LC5 dose pesticide with residual film method. P450 got the minimum at 12 h(0.5 times as CK), while CarE and GSTs got the lowest activity at 20 h(0.7 times as CK). With high dose of fluvalinate, contacting had more obvious effect on enzymatic activity than feeding.As a key enzyme in honeybee nervous system, it is crucial to neural information transfer. AChE can be affected by pesticide. The activity of AChE changed in 24 h after LC5 dose of imidacloprid and fluvalinate used. In the feeding method, low dose of imidacloprid reduced AChE, but higher than LC20 dose of imidacloprid had no significant effect on AChE activity. On the contary, high dose of fluvalinate inhibited AChE. In the residual film method, low dose of imidacloprid had no effect on the activity of AChE except LC30 which inhibited AChE. LC10 dose of fluvalinate significantly increased activity of AChE. Then with the dose of fluvalinate increased, the activity decreased gradually.Feeding with LC5 dose of imidacloprid, honeybee had significant changes on the transcriptom expression. With the extension of time, the effect of imidacloprid on honeybee transcriptom expression reduced gradually. This changed genes were mainly enriched in amino acid metabolism, lipid metabolism, nucleic acid metabolism, carbohydrate metabolism, energy metabolism, metabolism of cofactors and vitamin, polysaccharide synthesis and metabolism, immune system, exogenous compounds metabolism, etc. This changed metabolism systems were mainly used to strengthen the metabolism and resistance ability.With the same dose, different pesticide have different effect on the activity of detoxification enzymes. The toxicity of residual film method were higher than feeding method. The reason was that pesticide can be more easy degraded by the detoxification enzyme in midgut when it was eaten by honeybee,This article gives a comprehensive analysis of the effect of pesticide on honeybee from enzymatic activity to transcriptom expression. It lay the foundation for further studying honeybee pesticide metabolism mechanism and clarifying the effect of pesiticide.