Department of Biology, Queen's University, Kingston, Canada.
Department of Mathematics and Statistics, Queen's University, Kingston, Canada.
Pest Manag Sci. 2023 Jul;79(7):2581-2590. doi: 10.1002/ps.7439. Epub 2023 Mar 21.
Tebufenozide is widely used to control populations of the smaller tea tortrix, Adoxophyes honmai. However, A. honmai has evolved resistance such that straightforward pesticide application is an untenable long-term approach for population control. Evaluating the fitness cost of resistance is key to devising a management strategy that slows the evolution of resistance.
We used three approaches to assess the life-history cost of tebufenozide resistance with two strains of A. honmai: a tebufenozide-resistant strain recently collected from the field in Japan and a susceptible strain that has been maintained in the laboratory for decades. First, we found that the resistant strain with standing genetic variation did not decline in resistance in the absence of insecticide over four generations. Second, we found that genetic lines that spanned a range of resistance profiles did not show a negative correlation between their LD , the dosage at which 50 % of individuals died, and life-history traits that are correlates of fitness. Third, we found that the resistant strain did not manifest life-history costs under food limitation. Our crossing experiments indicate that the allele at an ecdysone receptor locus known to confer resistance explained much of the variance in resistance profiles across genetic lines.
Our results indicate that the point mutation in the ecdysone receptor, which is widespread in tea plantations in Japan, does not carry a fitness cost in the tested laboratory conditions. The absence of a cost of resistance and the mode of inheritance have implications for which strategies may be effective in future resistance management efforts. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
噻嗪酮被广泛用于控制小卷叶蛾，茶尺蠖的种群。然而，茶尺蠖已经进化出了抗药性，因此，直接使用农药来控制种群是一种不可持续的长期方法。评估抗性的适合度成本对于制定减缓抗性进化的管理策略至关重要。
我们使用三种方法评估了噻嗪酮抗性对两种茶尺蠖种群的生活史成本：一种是最近从日本田间采集的噻嗪酮抗性品系，另一种是实验室饲养了几十年的敏感品系。首先，我们发现具有遗传变异的抗性品系在没有杀虫剂的情况下，经过四代后，其抗性并没有下降。其次，我们发现遗传系跨越了一系列抗性谱，其 LD（50%个体死亡的剂量）与与适合度相关的生活史特征之间没有负相关关系。第三，我们发现，在食物限制的情况下，抗性品系没有表现出生活史成本。我们的杂交实验表明，在已知赋予抗性的蜕皮激素受体基因座的等位基因解释了遗传系之间抗性谱的大部分方差。
我们的结果表明，在日本茶园广泛存在的蜕皮激素受体点突变在测试的实验室条件下没有适合度成本。抗性没有成本，且遗传方式对未来抗性管理策略的有效性有影响。
