Data from: Cryptic individual scaling relationships and the evolution of morphological scaling

Morphological scaling relationships between organ and body size—also known as allometries—describe the shape of a species, and the evolution of such scaling relationships is central to the generation of morphological diversity. Despite extensive modeling and empirical tests, however, the modes of selection that generate changes in scaling remain largely unknown. Here, we mathematically model the evolution of the group-level scaling as an emergent property of individual-level variation in the developmental mechanisms that regulate trait and body size. We show that these mechanisms generate a “cryptic individual scaling relationship” unique to each genotype in a population, which determines body and trait size expressed by each individual, depending on developmental nutrition. We find that populations may have identical population-level allometries but very different underlying patterns of cryptic individual scaling relationships. Consequently, two populations with apparently the same morphological scaling relationship may respond very differently to the same form of selection. By focusing on the developmental mechanisms that regulate trait size and the patterns of cryptic individual scaling relationships they produce, our approach reveals the forms of selection that should be most effective in altering morphological scaling, and directs researcher attention on the actual, hitherto overlooked, targets of selection.

器官与体型间的形态缩放关系——亦称为异速生长（allometries）——刻画了物种的形态特征，而此类缩放关系的演化是形态多样性产生的核心驱动因素。尽管已有大量建模与实证检验工作，但催生缩放关系变化的自然选择模式仍在很大程度上未被探明。在此，我们将类群层面的缩放关系演化，建模为调控性状与体型发育的个体层面发育机制变异的涌现属性。我们发现，此类发育机制会生成一种“隐秘个体缩放关系”，该关系为种群内每个基因型所独有，其决定了每个个体在不同发育营养条件下所表现出的体型与性状大小。我们的研究显示，不同种群可能拥有完全一致的类群水平异速生长关系，但其底层的隐秘个体缩放关系模式却存在显著差异。因此，即便两个种群的形态缩放关系表面上完全相同，它们对同一类型的自然选择也会产生截然不同的响应。通过聚焦于调控性状大小的发育机制及其所催生的隐秘个体缩放关系模式，我们的研究方法揭示了在改变形态缩放方面最为有效的选择类型，并将研究者的注意力引向此前被忽视的真正选择靶点。