高温对抗性和敏感小菜蛾生命表参数及后代杀虫剂敏感性的影响

Effects of high temperature on life table parameters and the susceptibility to avermectin of progenies in insecticide-resistant and susceptible Plutella xylostella L. (Lepidoptera:Yponomeutidae)

为研究高温对抗性和敏感小菜蛾Plutella xylostella生物学适合度及抗药性进化的影响,本研究测定了温度对杀虫剂抗性和敏感小菜蛾实验种群生命表参数及后代对阿维菌素敏感性的影响。结果表明:与25℃相比,33.5℃条件下抗性和敏感种群的平均世代历期(D)、净生殖率(R0)、内禀增长率(rm)、周限增长率(λ)值、总产卵量、雌蛾平均寿命、日产卵量和孵化率均显著下降。在25℃下,抗性和敏感种群的rm,λ,D和日产卵量无显著差异,但抗性种群的R0略低于敏感种群(为敏感种群的87%)。在33.5℃下,抗性种群的rm和R0显著低于敏感种群(分别为敏感种群的75%和64%),抗性种群雌成虫寿命、总产卵量和孵化率显著也低于敏感种群。抗性种群在33.5℃下饲养1代后,后代对阿维菌素的抗性水平大幅下降,而相同处理下敏感种群对阿维菌素的抗性水平没有显著下降。上述结果表明,无论在常温还是高温条件下,抗性种群生物学适合度均低于敏感种群,尤其是高温下抗性种群适合度远低于敏感种群。抗性种群经高温饲养1代后对阿维菌素的抗性水平大幅下降可能与高温下抗性种群适合度显著较低有关。

To investigate the effects of high temperature on biological fitness and evolution of insecticide resistance, the life-table parameters and susceptibility to avermectin in the progenies of insecticide-resistant and -susceptible populations of Plutella xylostella were studied. The results showed that both resistant and susceptible populations displayed significantly lower developmental duration （D）, net reproduction rate （R0）, innate rate of increase （rm）, finite rate of increase （λ）, total fecundity number, average longevity of female adult, daily fecundity number and hatchability at 33.5℃ as compared to those at 25℃. There were no significant differences in rm, λ, D and daily fecundity number between the resistant population and the susceptible population, although R0 of the resistant population was slightly lower than that of the susceptible population at 25℃ （87% of the susceptible population）. However, compared to the susceptible population, the resistant population had significantly lower R0 （75% of the susceptible population）, rm （64% of the susceptible population）, average longevity of female, total fecundity number and hatchability at 33.5℃. The avermevtin resistance declined greatly in the progenies of resistant population after the insects were reared at 33.5℃ for one generation. However, no great decrease of avermectin resistance was found in the progenies of susceptible population under the same treatment condition. The results suggest that the biological fitness of resistant population was eventually lower than that of susceptible population at both high and normal temperatures. In particular, the fitness of resistant population was far lower than that of the susceptible population under high temperature condition. Significantly lower biological fitness of the resistant population under heat stress might result in the sharp decline of avermectin resistance in the progenies of the resistant population when the insects were reared at 33.5℃ for one generation.