Phylogenetic context determines the role of competition in adaptive radiation

Understanding ecological mechanisms regulating the evolution of biodiversity is of much interest to ecologists and evolutionary biologists. Adaptive radiation constitutes an important evolutionary process that generates biodiversity. Competition has long been thought to influence adaptive radiation, but the directionality of its effect and associated mechanisms remain ambiguous. Here, we report a rigorous experimental test of the role of competition on adaptive radiation using the rapidly evolving bacterium Pseudomonas fluorescens SBW25 interacting with multiple bacterial species that differed in their phylogenetic distance to the diversifying bacterium. We showed that the inhibitive effect of competitors on the adaptive radiation of P. fluorescens decreased as their phylogenetic distance increased. To explain this phylogenetic dependency of adaptive radiation, we linked the phylogenetic distance between P. fluorescens and its competitors to their niche and competitive fitness differenc...

阐明调控生物多样性演化的生态机制，始终是生态学家与进化生物学家极为关注的研究课题。适应辐射（Adaptive radiation）是产生生物多样性的重要进化过程。长期以来，学界认为竞争作用会影响适应辐射，但其效应的方向性与关联机制仍模糊不清。本研究以快速演化的荧光假单胞菌SBW25（Pseudomonas fluorescens SBW25）为研究对象，使其与多种和该发生适应性辐射的细菌的系统发育距离各不相同的细菌物种相互作用，针对竞争作用在适应辐射中所扮演的角色开展了严谨的实验检验。研究结果表明，竞争者对荧光假单胞菌SBW25适应辐射的抑制效应，会随着二者间系统发育距离的增加而减弱。为解释适应辐射的这一系统发育依赖性，我们将荧光假单胞菌与其竞争者之间的系统发育距离，与二者的生态位（niche）和竞争适合度（competitive fitness）差异建立了关联……