Beyond pairwise interactions: multispecies character displacement in Mexican freshwater fish communities

Competition has long been recognized as a central force in shaping evolution, particularly through character displacement. Yet research on character displacement is biased as it has focused almost exclusively on pairs of interacting species, while ignoring multispecies interactions. Communities are seldom so simple that only pairs of species interact, and it is not clear if inferences from pairwise interactions are sufficient to explain patterns of phenotypes in nature. Here we test for character displacement in a natural system of freshwater fishes in western Mexico that contains up to four congeneric species of the genus Poeciliopsis. We analyzed body shape differences between populations with different numbers of competitors while accounting for confounding environmental variables. Surprisingly, we found evidence for convergent character displacement in populations of P. prolifica, P. viriosa and P. latidens. We also found that the convergence in body shape was not
consistently in t...

竞争长期以来被认为是塑造演化的核心驱动力之一，尤其通过性状替换（character displacement）实现。然而，现有关于性状替换的研究存在明显偏倚：绝大多数研究仅聚焦于成对互作的物种，却忽略了多物种间的相互作用。自然群落极少仅存在成对物种间的互作，目前尚不明确从成对互作中得到的推论是否足以解释自然界中的表型格局。本研究针对墨西哥西部的淡水鱼类自然系统开展性状替换检验，该系统中最多包含隶属于新花鳉属（Poeciliopsis）的4个同属物种。我们分析了不同竞争者数量的种群间的体型差异，并控制了混淆性环境变量的影响。令人意外的是，我们在P. prolifica、P. viriosa与P. latidens的种群中发现了趋同性状替换的证据。此外，我们还发现，体型的趋同特征并未始终呈现出……（原文未完结）