胺菊酯选育淡色库蚊抗性株的研究

目的：实验室选育淡色库蚊胺菊酯抗性品系。方法：ＬＣ５０测定采用浸液法，选育工作参照ＯｍｅｒＳＭｅｔａｌ方法。结果：１９９６年连续用药筛选６代，抗性倍数在第４代曾达到１４倍，尔后种群数量逐渐衰落，至第６代未能继续传代。１９９７年重新选育，共连续用药筛选８代，前３代抗性水平逐步上升，达１３．０７倍；之后逐代下降，第６代降为４．５７倍，第７代有所回升，第８代又有降低。同时进一步研究抗性种群的吸血率、产卵率、各虫期的存活率等种群生存数据发现，与敏感品系相比抗性种群各值均有所下降，种群适合度有一定程度降低，相对适合度为０．２９。结论：本实验中抗胺菊酯品系抗性上升缓慢，可能是胺菊酯的作用机理及其作为击倒剂的作用特点所致。至于抗性种群有无遗传分化，尚需进一步研究。

Study on Resistant strain of Culex pipiens pallens Selecting with Tetramethrin

Culex pipiens pallens was selected successively for 8 generations with tetramethrin in laboratory.The LC 50 of selected strain increased from 0.140 ppm to 1.829ppm after 3 generations of selection (13.07 folds).Then the LC 50 went down every generation.The LC 50 is only 0.643ppm (4.57 folds) at the 6th generation.After that increase of LC 50 is not steady.Some biological parameters were compared between S strain and R strain,It was found that the rates of bloodfeeding and surviving in larvae and pupae of the 8th generation of R strain declined.Relative fitness by net reproductive rates (R 0) was 0.29.