Laboratoire d'Ecologie Alpine, UMR CNRS 5553, Université Joseph Fourier, BP 53, 38041, Grenoble Cedex 09, France.
Ecotoxicology. 2011 Aug;20(6):1184-94. doi: 10.1007/s10646-011-0663-8. Epub 2011 Apr 3.
Sustainable insect vector disease control strategies involve delaying the evolution of resistance to insecticides in natural populations. The evolutionary dynamics of resistance in the field is highly dependent on the fitness cost of resistance alleles. To successfully manage resistance evolution in target species, it is not only important to find evidence of fitness cost in resistant insects, but also to determine at which stage of the insect's life it is expressed. Here, we show that resistance costs to the bacterio-insecticide Bacillus thuringiensis subsp. israelensis (Bti) are expressed at all the life-stages of the dengue vector Aedes aegypti, including egg survival, larval development time, and female fecundity. We show that the storage of eggs for 4 months is long enough to counter-select resistance alleles. This suggests that Bti resistance is not likely to evolve in temperate climates where most mosquito species overwinter as eggs. In tropical regions with a rapid turn-over of generations, resistance alleles are likely to be counter-selected in only few generations without treatment through fitness costs expressed in terms of larval development time and female fecundity. We discuss the implications of our findings in terms of sustainable management strategies in light of the challenge of preserving the long-term efficiency of this environmentally safe anti-mosquito bio-insecticide.
可持续的昆虫病媒控制策略涉及延缓自然种群中对杀虫剂的抗性进化。抗性在田间的进化动态高度依赖于抗性等位基因的适应度代价。为了成功管理目标物种的抗性进化，不仅要找到抗性昆虫适应度代价的证据，还要确定它在昆虫生命的哪个阶段表达。在这里，我们表明，对苏云金芽孢杆菌亚种以色列变种（Bti）的细菌杀虫剂的抗性代价在登革热病媒埃及伊蚊的所有生命阶段都有表现，包括卵的存活率、幼虫发育时间和雌性生殖力。我们表明，将卵储存 4 个月足以对抗选择抗性等位基因。这表明，在大多数蚊种以卵越冬的温带气候中，Bti 抗性不太可能进化。在世代更替迅速的热带地区，通过幼虫发育时间和雌性生殖力表达的适应度代价，在没有处理的情况下，抗性等位基因可能在少数几代中就被对抗选择。我们根据保护这种环境安全的抗蚊生物杀虫剂长期有效性的挑战，讨论了我们的发现对可持续管理策略的影响。
