Ecological speciation in anemone-associated snapping shrimps (Alpheus armatus species complex)

Divergent natural selection driven by competition for limited resources can promote speciation, even in the presence of gene flow. Reproductive isolation is more likely to result from divergent selection when the partitioned resource is closely linked to mating. Obligate symbiosis and host fidelity (mating on or near the host) can provide this link, creating ideal conditions for speciation in the absence of physical barriers to dispersal. Symbiotic organisms often experience competition for hosts, and host fidelity ensures that divergent selection for a specific host or host habitat can lead to speciation and strengthen pre-existing reproductive barriers. Here, we present evidence that diversification of a sympatric species complex occurred despite the potential for gene flow and that partitioning of host resources (both by species and by host habitat) has contributed to this diversification. Four species of snapping shrimps (Alpheus armatus, A. immaculatus, A. polystictus and A. roquen...趋异自然选择（divergent natural selection）由有限资源竞争驱动，即便存在基因流（gene flow），仍可推动物种形成（speciation）。当分化的资源与交配行为紧密关联时，趋异选择更易引发生殖隔离（reproductive isolation）。专性共生（obligate symbiosis）与宿主保真度（host fidelity，即于宿主体表或其附近完成交配）可提供此类关联，在不存在扩散物理屏障的情况下为物种形成创造理想条件。共生生物往往会经历宿主资源的竞争，而宿主保真度可确保针对特定宿主或宿主生境的趋异选择能够推动物种形成，并强化既有的生殖隔离屏障。本研究提供证据显示，即便存在基因流潜力，同域物种复合群（sympatric species complex）仍可发生分化，且宿主资源的分化（按宿主物种及宿主生境划分）推动了这一分化过程。本次研究涉及四种枪虾（Alpheus armatus、A. immaculatus、A. polystictus及A. roquen……）