Lin Yong Wen, Wu Gang, Miyata Tadashi
Key Laboratory of Biopesticide and Chemical Biology, Fujian Agriculture and Forestry University, Ministry of Education, Fuzhou, Fujian 350002, China.
Pest Manag Sci. 2007 Sep;63(9):841-50. doi: 10.1002/ps.1402.
The effects of sublethal dosages of insecticides applied to Plutella xylostella L. (Lepidoptera: Yponomeutidae) and Lipaphis erysimi Kaltenbach (Homoptera: Aphidiidae) on the insecticide susceptibility of the surviving endoparasitoids, Cotesia plutellae Kurdjumov (Hymenoptera: Braconidae) and Diaeretiella rapae (M'Intosh) (Hymenoptera: Aphidiidae), were studied in Shangjie, Minhou, China. The susceptibility to methamidophos and the sensitivity of acetylcholinesterase (AChE) to methamidophos and dichlorvos in the adults of host insects were substantially lower than those in the two parasitoids. The host insects were treated with sublethal dosages of methamidophos in P. xylostella and of methamidophos and avermectin in L. erysimi. The cocoon formation in the two parasitoids decreased significantly, from 35.0% (control) to 13.0% (with methamidophos treatment) for C. plutellae; from 20.6% (control) to 9.0% (with methamidophos treatment) and from 24.3% (control) to 16.7% (with avermectin treatment) for D. rapae. The susceptibility to methamidophos of the resultant emerging adults of the two parasitoids was found to be significantly lower than that of the control when the parasitoids were left in contact with the same dosages of methamidophos. The average AChE activity inhibition by methamidophos and dichlorvos in 34-60 adults of the two parasitoids that emerged from the treatments (15.1% and 31.8% respectively for C. plutellae, and 21.1% and 26.9% for D. rapae) was also significantly lower than those of the controls (55.4% and 48.3% respectively for C. plutellae, and 42.9% and 51.7% for D. rapae). The bimolecular rate constant (k(i)) values of AChE to methamidophos and dichlorvos in the adults of parasitoids without the insecticide treatment were 1.78 and 1.56 times as high as those that emerged from the host insects treated with methamidophos for C. plutellae, and 1.91 and 1.66 times as high as those in the case of D. rapae. It is suggested that there is a difference in AChE sensitivity to insecticides between the resultant emerging parasitoids with and without insecticide pretreatment. Furthermore, the introduction of the insecticides to the host insects could be an important factor in the insecticide resistance development of the endoparasitoids. The natural selectivity would favour the parasitoids that had developed an insensitivity to the insecticide(s).
在中国福建闽侯上街，研究了亚致死剂量的杀虫剂施用于小菜蛾（鳞翅目：菜蛾科）和萝卜蚜（同翅目：蚜科）后，对存活的内寄生蜂——小菜蛾绒茧蜂（膜翅目：茧蜂科）和菜蚜茧蜂（膜翅目：蚜茧蜂科）杀虫剂敏感性的影响。宿主昆虫成虫对甲胺磷的敏感性以及乙酰胆碱酯酶（AChE）对甲胺磷和敌敌畏的敏感度显著低于两种寄生蜂。用亚致死剂量的甲胺磷处理小菜蛾宿主昆虫，用甲胺磷和阿维菌素处理萝卜蚜宿主昆虫。两种寄生蜂的结茧率显著降低，小菜蛾绒茧蜂从35.0%（对照）降至13.0%（甲胺磷处理）；菜蚜茧蜂从20.6%（对照）降至9.0%（甲胺磷处理）以及从24.3%（对照）降至16.7%（阿维菌素处理）。当寄生蜂与相同剂量的甲胺磷接触时，发现两种寄生蜂羽化出的成虫对甲胺磷的敏感性显著低于对照。处理后羽化出的两种寄生蜂34 - 60头成虫中，甲胺磷和敌敌畏对AChE活性的平均抑制率（小菜蛾绒茧蜂分别为15.1%和31.8%，菜蚜茧蜂分别为21.1%和26.9%）也显著低于对照（小菜蛾绒茧蜂分别为55.4%和48.3%，菜蚜茧蜂分别为42.9%和51.7%）。未用杀虫剂处理的寄生蜂成虫中，AChE对甲胺磷和敌敌畏的双分子速率常数（k(i)）值，小菜蛾绒茧蜂是经甲胺磷处理的宿主昆虫羽化出的寄生蜂的1.78倍和1.56倍，菜蚜茧蜂是其1.91倍和1.66倍。这表明经杀虫剂预处理和未经预处理羽化出的寄生蜂之间，AChE对杀虫剂的敏感性存在差异。此外，向宿主昆虫引入杀虫剂可能是内寄生蜂产生抗药性的一个重要因素。自然选择将有利于对杀虫剂产生不敏感性的寄生蜂。
