在无杀虫剂压力下淡色库蚊的抗性稳定性研究(英文)

本文对淡色库蚊（Ｃｕｌｅｘ ｐｉｐｉｅｎｓ ｐａｌｌｅｎｓ Ｃｏｑｕｉｌｌｅｔｔ）的毒死蜱抗性品系、抗一敏杂交品系及抗性酯酶Ｂ_２纯合品系在无杀虫剂压力选择下的抗性水平变化进行了研究。结果表明，在毒死蜱抗性品系中，抗性水平逐代下降，ＬＣ_（５０）从Ｆ_０代的０．２０９９ｍｇ／Ｌ快速降至Ｆ_８代的０．０２６２ｍｇ／Ｌ，然后继续缓慢地降至Ｆ_（１６）代的０．０２０７ｍｇ／Ｌ。从毒死蜱抗性品系中的这种抗性水平下降，可以推断该品系中并不是纯的高抗性酯酶基因扩增个体，在传代中抗性个体的比例由于其生物学方面的不适应性而逐步减少。本研究中的抗性品系与敏感品系的杂交群体的抗性变化趋势也证实了这种推理。在纯的抗性酯酶Ｂ_２基因扩增品系中，抗性水平则在后代中基本上保持稳定，并且所有的个体抗性水平和酯酶活力水平更趋集中。本文进一步对蚊虫抗性的演替进行了讨论。

STABILITY OF ORGANOPHOSPHATE RESISTANCE IN CULEX PIPIENS PALLENS COQUILLETT UNDER RELAXATION OF INSECITICDE SELECTION

The stability of resistance in the organophosphate resistant strain of Culex pipiens pallens with amplification of single gene coding for esterase B_2 was determined under relaxation of insecticide selection. Insecticide resistance and amplification of esterase were both lost when strains were not homozygous for the presence of amplified gene, probably due to biological disadvantage of the esterase gene. LC_(50) and LC_(95) of chlorpyrifos for this strain were 0. 2099 mg/L and 0.9036 mg/L in the F_(0), generation respectively, but 0.0207 mg/L and 2. 8027 mg/L respectively in the P_(16) generation. In the homozygous strain, insecticide resistance was still stable and amplification of esterase remained after 16 generations under relaxation of insecticide selection, which indicated that copy of esterase gene was not lost in the offspring of this strain. The evolution of insecticide resistance in mosquitoes is discussed.