Parasites contribute to ecologically dependent postmating isolation in the adaptive radiation of three spined stickleback

Spatial variation in parasitic infections is common, and has the potential to drive population divergence and the reproductive isolation of hosts. However, despite support from theory and model laboratory systems, little strong evidence has been forthcoming from the wild. Here, we show that parasites are likely to cause reproductive isolation in the adaptive radiation of three-spined stickleback. Adjacent wild populations on the Scottish island of North Uist differ greatly and consistently in the occurrence of different parasites that have substantial effects on fitness. Laboratory-reared fish are more resistant to experimental infection by parasite species from their own population. Furthermore, hybrid backcrosses between the host populations are more resistant to parasites from the parental population to which they are more closely related. These patterns provide strong evidence that parasites can cause ecological speciation, by contributing to selection against migrants and ecologica...

寄生虫感染的空间分布差异普遍存在，且有可能推动宿主种群分化与生殖隔离。然而，尽管理论研究与实验室模式系统已提供相关佐证，但自然野外环境中鲜有确凿证据问世。本研究证实，寄生虫或可引发三刺棘鱼（three-spined stickleback）适应性辐射过程中的生殖隔离。苏格兰北尤伊斯特岛（North Uist）上的相邻野生种群，在携带对宿主适合度（fitness）具有显著影响的不同寄生虫类群方面，存在显著且稳定的差异。实验室繁育的棘鱼对源自其原生种群的寄生虫的实验感染，展现出更强的抗性。此外，宿主种群间的杂交回交个体，对与其亲缘关系更近的亲本种群的寄生虫，同样表现出更强的抗性。上述模式提供了强有力的证据，表明寄生虫可通过对迁移个体施加选择压、推动生态物种形成（ecological speciation），具体途径包括对迁移个体的选择以及生态...