Department of Entomology, University of Minnesota, St. Paul, MN, United States of America.
PLoS One. 2022 Jul 21;17(7):e0271417. doi: 10.1371/journal.pone.0271417. eCollection 2022.
Although insecticide formulations and spray rates are optimized to achieve lethal exposure, there are many factors in agricultural settings that can reduce the effective exposure of insect pests. These include weather patterns, timing of application, chemical degradation/volatilization, plant structural complexity, and resistant populations. While sub-lethal exposure to insecticides can still have negative impacts on pest populations, they can also lead to stimulatory, or hormetic, responses that can increase the fitness of surviving insects. Sub-lethal concentrations may also produce increased tolerance in the offspring of surviving adults through transgenerational effects. Sub-lethal effects are pertinent for the invasive fruit pest, spotted-wing Drosophila, Drosophila suzukii (Matsumura), because its small size, diurnal movement patterns, and utilization of hosts with complex plant structures, such as caneberries and blueberries, make effective insecticide applications tenuous. In this study, we measured spotted-wing Drosophila survivorship, reproductive performance, and offspring tolerance in flies exposed to sub-lethal concentrations of three commonly-used insecticides (zeta-cypermethrin, spinetoram, and pyrethrin). We found some evidence for hormesis, with survival effects being sex- and concentration-dependent for all insecticides. Males were far more susceptible to insecticides than females, which in some cases exhibited higher eclosion success and reproductive rates when exposed to sub-lethal doses. We did not observe significant transgenerational effects at sub-lethal concentrations, despite trends of increased offspring viability for zeta-cypermethrin and spinetoram. More research, however, is needed to fully understand the role that sub-lethal effects may play in pest population dynamics, insecticide efficacy, and the development of genetic resistance.
尽管杀虫剂配方和喷雾率经过优化以实现致死暴露，但农业环境中有许多因素会降低害虫的有效暴露。这些因素包括天气模式、施药时间、化学降解/挥发、植物结构复杂性和抗药性种群。虽然亚致死接触杀虫剂仍然会对害虫种群产生负面影响，但它们也可能导致刺激或适应反应，从而提高幸存昆虫的适应性。亚致死浓度还可能通过跨代效应在幸存成虫的后代中产生增加的耐受性。亚致死效应与入侵性果实害虫斑点翅果蝇 Drosophila suzukii (Matsumura) 有关，因为其体型小、昼夜活动模式以及利用具有复杂植物结构的宿主（如醋栗和蓝莓），使得有效施药变得困难。在这项研究中，我们测量了暴露于三种常用杀虫剂（zeta-氯菊酯、spinetoram 和除虫菊素）的亚致死浓度下斑点翅果蝇的存活率、繁殖性能和后代耐受性。我们发现了一些适应现象的证据，所有杀虫剂的生存效应都与性别和浓度有关。雄性比雌性更容易受到杀虫剂的影响，在某些情况下，暴露于亚致死剂量下，雄性的羽化成功率和繁殖率更高。我们没有观察到亚致死浓度下的显著跨代效应，尽管 zeta-氯菊酯和 spinetoram 的后代活力有增加的趋势。然而，需要更多的研究来充分了解亚致死效应在害虫种群动态、杀虫剂功效和遗传抗性发展中可能发挥的作用。
