| Heavy metals and pesticides are common farmland pollutants.In order to explore the effects of single and combined pollution of heavy metal copper(Cu)and pesticide avermectin(Av)on animals and the detoxification mechanism of animals to toxicant stress,the phytophagous insect Ostrinia furnacalis was used as the research object in this paper.Heavy metal Cu and pesticide Av were added to artificial feed,and normal feed without addition was used as control.The effects of 50 mg/kg Cu,0.039 mg/kg abamectin and their combined stress on the growth and development,adult reproduction behavior and activities of different detoxification enzymes(including glutathione S-transferase GST,acid phosphatase ACP,alkaline phosphatase AKP,carboxylesterase Car E and acetylcholinesterase ACh E)of Ostrinia furnacalis were studied.The specific results are as follows:1.Cu/Av stress has a certain inhibitory effect on the growth and reproduction of Asian corn borer.The post-embryonic development period(larval duration+pupal duration)of male and female O.furnacalis treated with Cu alone was significantly shortened.After Av treatment alone,the post-embryonic development period of male and female was significantly prolonged,which was 67.07% and 67.38% longer than that of CK,respectively.After Cu treatment,the weight of pupae and adults decreased significantly.The body weight of female pupa,male pupa and female adult of O.furnacalis was significantly inhibited by Av treatment alone,which was 26.50%,8.96% and 12.46% lower than that of CK,respectively.Av+Cu treatment inhibited the growth and development of O.furnacalis,mainly reflected in the significant prolongation of post-embryonic development duration,increased larval mortality,and the body weight of male and female pupae and female adults was significantly lower than that of CK and was the lowest.The number of eggs laid by O.furnacalis decreased significantly under each toxicant treatment,but the egg hatching rate was not significantly different.2.The courtship behavior of Asian corn borer was disturbed after Cu/Av stress.The highest courtship percentage and average courtship time of each dark period after Cu treatment decreased with the dark period,while CK increased first and then decreased with the dark period.After Av treatment,the courtship behavior of female adults was promoted,the highest courtship percentage reached 100% in all dark periods except 5th dark period,and the average courtship duration was significantly longer than that of CK except for the third dark period.After Av+Cu treatment,similar to the Av treatment group,the courtship behavior of female adults was stimulated under each dark period.The average courtship duration under each dark period was significantly longer than that of CK and Cu treatment and had no significant difference with the Av treatment group,up to 6.16 h.3.Cu/Av treatment inhibited the orientation behavior of male adults of O.furnacalis.In the experimental combination,after the male or female moths were poisoned,the rate of pheromone source in each group was significantly lower than that in CK.In the experimental combination,both male and female moths were stressed by the agent.After Av+Cu treatment,the pheromone source rate and oviposition amounts of male adults decreased significantly and were the lowest,while Cu and Av single stress had no significant difference with CK,and the two agents had a certain synergistic effect.4.Cu/Av treatment affected the detoxification enzyme activity of male Asian corn borer.The activities of GST,Car E,AKP and ACh E in the 3rd instar larvae of O.furnacalis fed with Cu-containing diet were not significantly different from those of CK.Only ACP specific activity increased significantly.After AV treatment,the activities of GST,Car E,ACP and ACh E were significantly induced,while AKP activity was significantly inhibited.Under the combined stress,the specific activities of GST,Car E and ACP in the 3rd instar larvae were significantly induced,while AKP and ACh E were not significantly different from the control.The two agents had a combined effect: the induction effect on GST was stronger than that of single agent,while the induction or inhibition of Car E,AKP and ACh E was weaker than that of single agent. |
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