小菜蛾及菜蛾绒茧蜂乙酰胆碱酯酶敏感性的相关变化

用生物测定和生化检测的方法，对福州地区小菜蛾Plutella xylostella和菜蛾绒茧蜂Apanteles plutellae的抗药性及两种昆虫乙酰胆碱酯酶对杀虫剂的敏感性进行了田间监测。结果显示，从1998年9月至1999年4月，小菜蛾乙酰胆碱酯酶对6种有机磷和氨基甲酸酯杀虫剂敏感性逐渐恢复，寄生于同一虫源的菜蛾绒茧蜂乙酰胆碱酯酶敏感性的变化也呈明显的相关性，但菜蛾绒茧蜂乙酰胆碱酯酶的敏感性高于其寄主小菜蛾。脱离选择压力后，两种昆虫对杀虫剂的敏感性迅速恢复,乙酰胆碱酯酶的K_i值显著增高。对乙酰胆碱酯酶的K_m、V_max和K_i值测定结果表明，两种昆虫对有机磷和氨基甲酸酯杀虫剂的抗性与乙酰胆碱酯酶对杀虫剂的不敏感性有关。此外还研究了不同发育期小菜蛾乙酰胆碱酯酶活性及其K_i值的变化。探讨了在杀虫剂选择压力下，两种昆虫乙酰胆碱酯酶敏感性的环境适应性变化机制。

Correlated change of acetylcholinesterase sensitivity between Plutella xylostella and its parasitoid Apanteles plutellae

The acetylcholinesterase (AChE) sensitivity and insecticide resistance of Plutella xylostella and its parasitoid, Apanteles plutellae Kurd.collected from Fuzhou, Fujian Province, were detected and monitored by bioassays and biochemical analyses. The results show that the AChE sensitivity of P.xylostella to six kinds of organophosphorus and carbamate insecticides increased gradually from September 1998 to April 1999,and that sensitivity of A.plutellae (collected from the corresponding hosts) showed the same trend. AChE sensitivity was higher in A.plutellae than in P.xylostella . After release from the selective pressure of the insecticides, both P.xylostella and A.plutellae displayed a rapid recovery in susceptibility to these insecticides and a significant increase in the K i value of AChE. Insecticide resistance was associated with insensitivity to AChE in P. xylostella and A. plutellae based on the kinetic parameters, K m , V max and the bimolecular rate constant K i. This paper also profiles the K i activity of AChE at different developmental stages of susceptible and resistant P.xylostella , and discusses the possible mechanism of AChE sensitivity in natural populations of both P.xylostella and A. plutellae .