Wu Taoping, Rodrigues Anoushka A, Fayle Tom M, Henry Lee M
School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK.
Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Ceske Budejovice, Czech Republic.
Ecol Lett. 2025 Feb;28(2):e70082. doi: 10.1111/ele.70082.
Facultative symbionts are widespread in arthropods and can provide important services such as protection from natural enemies. Yet what shapes associations with defensive symbionts in nature remains unclear. Two hypotheses suggest that interactions with either antagonists or host plants explain the prevalence of symbionts through shared selective pressures or vectors of symbiont transmission. Here we investigate the factors determining similarities in the Hamiltonella defensa symbiosis shared amongst field-collected aphid species. After accounting for host species relatedness, we find that Hamiltonella's genotype distribution aligns with sharing the same parasitoids, rather than host plants, highlighting parasitoids and hosts as key selective agents shaping the symbiosis across aphid species. Our data indicates parasitoid host specificity drives the prevalence of specific aphid-Hamiltonella associations, suggesting defensive symbioses are maintained by the selective pressure imposed by dominant parasitoids and their aphid hosts. These findings underscore the importance of interactions with natural enemies in explaining patterns of defensive symbiosis in nature.
兼性共生体在节肢动物中广泛存在，能够提供重要的服务，比如抵御天敌。然而，在自然界中，是什么塑造了与防御性共生体的关联仍不清楚。有两种假说认为，与拮抗物或宿主植物的相互作用通过共享的选择压力或共生体传播媒介来解释共生体的普遍存在。在这里，我们研究了决定田间采集的蚜虫物种中汉氏 defensa 共生关系相似性的因素。在考虑宿主物种亲缘关系后，我们发现汉氏菌的基因型分布与共享相同的寄生蜂而非宿主植物一致，这突出了寄生蜂和宿主是塑造蚜虫物种间共生关系的关键选择因子。我们的数据表明，寄生蜂宿主特异性驱动了特定蚜虫 - 汉氏菌关联的普遍存在，这表明防御性共生关系是由优势寄生蜂及其蚜虫宿主施加的选择压力维持的。这些发现强调了与天敌的相互作用在解释自然界中防御性共生模式方面的重要性。
