Data from: Trait evolution in adaptive radiations: modeling and measuring interspecific competition on phylogenies

The incorporation of ecological processes into models of trait evolution is important for understanding past drivers of evolutionary change. Species interactions have long been thought to be key drivers of trait evolution. However, models for comparative data that account for interactions between species are lacking. One of the challenges is that such models are intractable and difficult to express analytically. Here we present phylogenetic models of trait evolution that include interspecific competition among chosen species. Competition is modeled as a tendency of sympatric species to evolve toward difference from one another, producing trait overdispersion and high phylogenetic signal. The model predicts elevated trait variance across species and a slowdown in evolutionary rate both across the clade and within each branch. The model also predicts a reduction in correlation between otherwise correlated traits. We use an approximate Bayesian computation approach to estimate model parameters. We find reasonable power to detect competition in sufficiently large (20+ species) trees compared with Brownian trait evolution and with Ornstein-Uhlenbeck and early burst models. We apply the model to examine the evolution of bill morphology of Darwin’s finches and find evidence that competition affects the evolution of bill length.将生态过程整合至性状进化模型之中，对于解析进化变化的既往驱动机制具有重要意义。长期以来，物种间相互作用被视作性状进化的关键驱动因素，但目前仍缺乏能够考量物种间相互作用的比较数据模型。此类模型面临的核心挑战之一，在于其解析复杂度极高且难以通过解析形式进行表述。本研究提出一类包含选定物种种间竞争关系的性状进化系统发育模型（phylogenetic models）：该模型将竞争定义为同域物种朝彼此性状分化方向演化的趋势，由此可产生性状过分散现象与较高的系统发育信号。模型预测，在整个类群及各进化分支内部，物种间的性状方差将升高，进化速率则会出现减缓；此外，模型还预测，原本存在相关性的性状之间的相关程度会有所降低。我们采用近似贝叶斯计算（approximate Bayesian computation）方法对模型参数进行估计。相较于布朗运动性状进化模型、奥恩斯坦-乌伦贝克（Ornstein-Uhlenbeck）模型与早期爆发模型，当系统发育树包含足够多的物种（20种及以上）时，本模型能够有效检测到竞争信号。我们将该模型应用于达尔文雀（Darwin’s finches）的喙形态进化分析，发现了竞争影响喙长进化的相关证据。