Department of BioSciences, Rice University, Houston, TX, United States.
Department of Biological Sciences, George Washington University, Washington, DC, United States.
J Evol Biol. 2024 Feb 14;37(2):248-255. doi: 10.1093/jeb/voae005.
Ecology and geography can play important roles in the evolution of reproductive isolation across the speciation continuum, but few studies address both at the later stages of speciation. This notable gap in knowledge arises from the fact that traditional ecological speciation studies have predominantly focused on the role of ecology in initiating the speciation process, while many studies exploring the effect of geography (e.g., reinforcement) concentrate on species pairs that lack divergent ecological characteristics. We simultaneously examine the strength of habitat isolation and sexual isolation among three closely related species of Belonocnema gall-forming wasps on two species of live oaks, Quercus virginiana and Q. geminata, that experience divergent selection from their host plants and variable rates of migration due to their geographic context. We find that the strength of both habitat isolation and sexual isolation is lowest among allopatric species pairs with the same host plant association, followed by allopatric species with different host plant associations, and highest between sympatric species with different host-plant associations. This pattern suggests that divergent selection due to different host use interacts with geography in the evolution of habitat isolation and sexual isolation during the later stages of speciation of Belonocnema wasps.
生态学和地理学在物种形成连续体中的生殖隔离进化中可以起到重要作用，但很少有研究在物种形成的后期阶段同时考虑这两个因素。造成这一知识缺口的原因是，传统的生态物种形成研究主要集中在生态学在启动物种形成过程中的作用，而许多探索地理学（例如，强化）影响的研究则集中在缺乏生态特征差异的物种对上。我们同时研究了在两种活栎树（Quercus virginiana 和 Q. geminata）上的三种亲缘关系密切的 Belonocnema 瘿蜂之间的栖息地隔离和性隔离的强度，这两种活栎树因其宿主植物而经历了不同的选择，并且由于其地理背景而具有不同的迁移率。我们发现，具有相同宿主植物组合的同域种对之间的栖息地隔离和性隔离的强度最低，其次是具有不同宿主植物组合的异域种对，而具有不同宿主植物组合的同域种对之间的强度最高。这一模式表明，由于不同的宿主利用而产生的分歧选择与地理学在 Belonocnema 瘿蜂物种形成后期的栖息地隔离和性隔离进化中相互作用。
