College of Veterinary Medicine, Department of Biomedical Sciences, Cornell University, 930 Campus Rd, Ithaca, NY, 14853, USA.
Nat Commun. 2024 May 28;15(1):4208. doi: 10.1038/s41467-024-48324-y.
Birds are represented by 11,000 species and a great variety of body masses. Modular organisation of trait evolution across birds has facilitated simultaneous adaptation of different body regions to divergent ecological requirements. However, the role modularity has played in avian body size evolution, especially small-bodied, rapidly evolving and diverse avian subclades, such as hummingbirds and songbirds, is unknown. Modularity is influenced by the intersection of biomechanical restrictions, adaptation, and developmental controls, making it difficult to uncover the contributions of single factors such as body mass to skeletal organisation. We develop a novel framework to decompose this complexity, assessing factors underlying the modularity of skeletal proportions in fore-limb propelled birds distributed across a range of body masses. We demonstrate that differences in body size across birds triggers a modular reorganisation of flight apparatus proportions consistent with biomechanical expectations. We suggest weakened integration within the wing facilitates radiation in small birds. Our framework is generalisable to other groups and has the capacity to untangle the multi-layered complexity intrinsic to modular evolution.
鸟类由 11000 个物种和各种各样的体重组成。特征进化的模块组织使不同的身体区域能够同时适应不同的生态需求。然而，模块性在鸟类体型进化中的作用，特别是在体型较小、进化迅速和多样化的鸟类亚目中，如蜂鸟和鸣禽，尚不清楚。模块性受到生物力学限制、适应和发育控制的交叉影响，这使得很难揭示单个因素（如体重）对骨骼组织的贡献。我们开发了一种新的框架来分解这种复杂性，评估在一系列体重范围内分布的前肢推进鸟类的骨骼比例模块性的基础因素。我们证明，鸟类之间体型的差异引发了飞行器官比例的模块化重新组织，这与生物力学预期一致。我们认为，在小型鸟类中，翅膀内的整合减弱，从而促进了辐射。我们的框架具有通用性，可以解决模块进化内在的多层次复杂性。
