There is increasing demand for sustainable pest management to reduce harmful effects of pesticides on the environment and human health. For pest aphids, biological control with parasitoid wasps provides a welcome alternative, particularly in greenhouses. However, aphids are frequently infected with the heritable bacterial endosymbiont Hamiltonella defensa, which increases resistance to parasitoids and thereby hampers biological control. Using the black bean aphid (Aphis fabae) and its main parasitoid Lysiphlebus fabarum, we tested whether prior adaptation of parasitoids can improve the control of symbiont‐protected pests. We had parasitoid lines adapted to two different strains of H. defensa by experimental evolution, as well as parasitoids evolved on H. defensa‐free aphids. We compared their ability to control caged aphid populations comprising 60% unprotected and 40% H. defensa‐protected aphids, with both H. defensa strains present in the populations. Parasitoids that were not adapted to H. defensa had virtually no effect on aphid population dynamics compared to parasitoid‐free controls, but one of the adapted lines and a mixture of both adapted lines controlled aphids successfully, strongly benefitting plant growth. Selection by parasitoids altered aphid population composition in a very specific manner. Aphid populations became dominated by H. defensa‐protected aphids in the presence of parasitoids, and each adapted parasitoid line selected for the H. defensa strain it was not adapted to. This study shows, for the first time, that prior adaptation of parasitoids improves biological control of symbiont‐protected pests, but the high specificity of parasitoid counter‐resistance may represent a challenge for its implementation.

中文翻译：

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寄生蜂的预先适应改善了对共生体保护害虫的生物控制。


人们对可持续害虫管理的需求不断增加，以减少农药对环境和人类健康的有害影响。对于害虫蚜虫，用寄生黄蜂进行生物防治提供了一种受欢迎的替代方案，特别是在温室中。然而，蚜虫经常感染可遗传的细菌内共生菌防御汉密尔顿氏菌，这会增加对寄生蜂的抵抗力，从而阻碍生物防治。利用黑豆蚜虫 ( Aphis fabae ) 及其主要寄生蜂Lysiphlebus fabarum ，我们测试了寄生蜂的预先适应是否可以改善对共生保护害虫的控制。我们通过实验进化获得了适应两种不同H. defensa品系的寄生蜂品系，以及在不含H. defensa 的蚜虫上进化出的寄生蜂。我们比较了它们控制笼养蚜虫种群的能力，其中包括 60% 未受保护的蚜虫和 40% H. defensa保护的蚜虫，两种H. defensa菌株都存在于种群中。与无寄生蜂的对照相比，不适应H. defensa的寄生蜂对蚜虫种群动态几乎没有影响，但其中一种适应品系和两种适应品系的混合物成功地控制了蚜虫，极大地有利于植物生长。寄生蜂的选择以一种非常特殊的方式改变了蚜虫种群的组成。在存在拟寄生物的情况下，蚜虫种群以受H. defensa保护的蚜虫为主，并且每个适应的拟寄生物系都选择了它不适应的H. defensa品系。 这项研究首次表明，寄生蜂的预先适应可以改善对共生保护害虫的生物防治，但寄生蜂反抗性的高度特异性可能对其实施构成挑战。