Hubei Engineering Technology for Pest Forewarning and Management, College of Agriculture, Yangtze University, Jingzhou, China.
The Ministry of Agriculture and Rural Affairs Key Laboratory of Integrated Pest Management of Tropical Crops, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, China.
Pest Manag Sci. 2022 Jun;78(6):2129-2140. doi: 10.1002/ps.6839. Epub 2022 Mar 1.
Species displacement by the outcome of interspecific competition is of particular importance to pest management. Over the past decade, spinetoram has been extensively applied in control of the two closely related thrips Megalurothrips usitatus and Frankliniella intonsa worldwide, while whether its resistance is implicated in mediating interspecific interplay of the two thrips remains elusive to date.
Field population dynamics (from 2017 to 2019) demonstrated a trend toward displacement of F. intonsa by M. usitatus on cowpea crops, supporting an existing interspecific competition. Following exposure to spinetoram, M. usitatus became the predominate species, which suggests the use of spinetoram appears to be responsible for mediating interspecific interactions of the two thrips. Further annual and seasonal analysis (from 2016 to 2020) of field-evolved resistance dynamics revealed that M. usitatus developed remarkably higher resistance to spinetoram compared to that of F. intonsa, implying a close relationship between evolution of spinetoram resistance and their competitive interactions. After 12 generations of laboratory selection, resistance to spinetoram in M. usitatus and F. intonsa increased up to 64.50-fold and 28.33-fold, and the average realized heritability (h ) of resistance was calculated as 0.2550 and 0.1602, respectively. Interestingly, two-sex life table analysis showed that the spinetoram-resistant strain of F. intonsa exhibited existing fitness costs, but not the M. usitatus. These indicate that a rapid development of spinetoram resistance and the lack of associated fitness costs may be the mechanism underlying recent dominance of M. usitatus over F. intonsa.
Collectively, our results uncover the involvement of insecticide resistance in conferring displacement mechanism behind interspecific competition, providing a framework for understanding the significance of the evolutionary relationships among insects under ongoing changing environments. These findings also can be invaluable in proposing the most appropriate strategies for sustainable thrips control programs. © 2022 Society of Chemical Industry.
种间竞争的结果导致物种替代对害虫管理尤为重要。在过去的十年中，螺虫乙酯已被广泛用于控制两种密切相关的蓟马——烟蓟马和美洲斑潜蝇——在世界各地，但其抗性是否涉及到两种蓟马的种间相互作用仍不得而知。
田间种群动态（2017 年至 2019 年）表明，在豇豆作物上，美洲斑潜蝇替代了烟蓟马，这支持了现有的种间竞争。在接触螺虫乙酯后，烟蓟马成为优势种，这表明螺虫乙酯的使用似乎负责调节两种蓟马的种间相互作用。进一步对田间进化抗性动态的年度和季节性分析（2016 年至 2020 年）表明，与美洲斑潜蝇相比，烟蓟马对螺虫乙酯的抗性发展得更高，这意味着螺虫乙酯抗性的进化与其竞争相互作用之间存在密切关系。经过 12 代的实验室选择，烟蓟马和美洲斑潜蝇对螺虫乙酯的抗性分别增加了 64.50 倍和 28.33 倍，抗性的平均实现遗传力（h）分别计算为 0.2550 和 0.1602。有趣的是，两性生命表分析表明，对螺虫乙酯具有抗性的美洲斑潜蝇品系表现出存在的适合度代价，但烟蓟马没有。这表明螺虫乙酯抗性的快速发展和缺乏相关的适合度代价可能是烟蓟马近期对美洲斑潜蝇优势的机制。
总之，我们的研究结果揭示了杀虫剂抗性在种间竞争背后的替代机制中的作用，为理解在不断变化的环境下昆虫之间进化关系的重要性提供了一个框架。这些发现对于提出最适当的可持续蓟马控制方案也具有重要意义。©2022 化学工业协会。
