Data from: Allometric constraints and the evolution of allometry

Morphological traits often covary within and among species according to simple power laws referred to as allometry. Such allometric relationships may result from common growth regulation, and this has given rise to the hypothesis that allometric exponents may have low evolvability and constrain trait evolution. We formalize hypotheses for how allometry may constrain morphological trait evolution across taxa, and test these using more than three-hundred empirical estimates of static (within-species) allometric relations of animal morphological traits. Although we find evidence for evolutionary changes in allometric parameters on million-year, cross-species time scales, there is limited evidence for microevolutionary changes in allometric slopes. Accordingly, we find that static allometries often predict evolutionary allometries on the subspecies level, but less so across species. Although there is a large body of work on allometry in a broad sense that includes all kinds of morphological trait-size relationships, we found relatively little information about the evolution of allometry in the narrow sense of a power relationship. Despite the many claims of microevolutionary changes of static allometries in the literature, hardly any of these apply to narrow-sense allometry, and we argue that the hypothesis of strongly constrained static allometric slopes remains viable.

形态性状在物种内部及物种间的协同变异，通常遵循被称为异速生长（allometry）的简单幂律规律。此类异速生长关系可能源于共同的生长调控机制，由此催生了“异速生长指数演化灵活性较低，且会约束性状演化”的假说。我们针对异速生长如何在不同类群中约束形态性状演化构建了相关假说，并通过超过300项针对动物形态性状的静态（物种内）异速生长关系的实证估算数据对这些假说进行检验。尽管我们在跨物种的百万年级时间尺度上发现了异速生长参数发生演化改变的证据，但关于异速生长斜率的微演化改变的证据却十分有限。据此我们发现，静态异速生长通常可以预测亚种水平上的演化异速生长，但在跨物种层面的预测效果则相对较差。尽管学界已就广义异速生长（涵盖各类形态性状-体型大小关系）开展了大量研究，但针对狭义幂律形式的异速生长演化的相关信息却相对匮乏。尽管文献中存在诸多关于静态异速生长发生微演化改变的论断，但其中几乎无一涉及狭义异速生长；我们认为，“静态异速生长斜率受到强烈约束”这一假说依然成立。