Long-term patterns of phenotypic change are the cumulative results of tens of thousands to millions of years of evolution. Yet, empirical and theoretical studies of phenotypic selection are largely based on contemporary populations. The challenges in studying phenotypic evolution, in particular trait–fitness associations in the deep past, are barriers to linking micro- and macroevolution. Here, we capitalize on the unique opportunity offered by a marine colonial organism commonly preserved in the fossil record to investigate trait–fitness associations over 2 Myr. We use the density of female polymorphs in colonies of Antartothoa tongima as a proxy for fecundity, a fitness component, and investigate multivariate signals of trait–fitness associations in six time intervals on the backdrop of Pleistocene climatic shifts. We detect negative trait–fitness associations for feeding polymorph (autozooid) sizes, positive associations for autozooid shape but no particular relationship between fecundity and brood chamber size. In addition, we demonstrate that long-term trait patterns are explained by palaeoclimate (as approximated by ∂18O), and to a lesser extent by ecological interactions (i.e. overgrowth competition and substrate crowding). Our analyses show that macroevolutionary outcomes of trait evolution are not a simple scaling-up from the trait–fitness associations.

中文翻译：

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性状-适应度关联无法预测 200 万年间的物种内表型进化

表型变化的长期模式是数万至数百万年进化的累积结果。然而，表型选择的经验和理论研究主要基于当代人群。研究表型进化的挑战，特别是过去的特征-适应度关联，是将微观进化和宏观进化联系起来的障碍。在这里，我们利用通常保存在化石记录中的海洋殖民生物提供的独特机会来调查超过 2 Myr 的性状-适应性关联。我们使用 Antartothoa tongima 群落中雌性多态性的密度作为繁殖力的代理，这是一个适合度的组成部分，并在更新世气候变化的背景下，在六个时间间隔内研究性状-适合度关联的多变量信号。我们检测到喂养多形性（自体动物）大小的负性状-适应性关联，自体动物形状的正关联，但繁殖力和育雏室大小之间没有特殊关系。此外，我们证明了长期性状模式可以通过古气候（由∂18O 近似）来解释，并在较小程度上通过生态相互作用（即过度生长竞争和基质拥挤）来解释。我们的分析表明，特征进化的宏观进化结果并不是特征-适应度关联的简单放大。并在较小程度上通过生态相互作用（即过度生长竞争和基质拥挤）。我们的分析表明，特征进化的宏观进化结果并不是特征-适应度关联的简单放大。并在较小程度上通过生态相互作用（即过度生长竞争和基质拥挤）。我们的分析表明，特征进化的宏观进化结果并不是特征-适应度关联的简单放大。