Trait evolution, resource specialization and vulnerability to plant extinctions among Antillean hummingbirds

Species traits are thought to predict feeding specialisation and the vulnerability of a species to extinctions of interaction partners, but the context in which a species evolved and currently inhabits may also matter. Notably, the predictive power of traits may require that traits evolved to fit interaction partners. Furthermore, local abiotic and biotic conditions may be important. On islands, for instance, specialised and vulnerable species are predicted to be found mainly in mountains, whereas species in lowlands should be generalized and less vulnerable. We evaluated these predictions for hummingbirds and their nectar-food plants on Antillean islands. Our results suggest that the rates of hummingbird trait divergence were higher among ancestral mainland forms before the colonization of the Antilles. In correspondence with the limited trait evolution that occurred within the Antilles, local abiotic and biotic conditions – not species traits – correlate with hummingbird resource spec...物种性状（species traits）被认为可预测其取食特化程度，以及该物种在交互伙伴灭绝时的脆弱性，但物种演化所处的背景与当前栖息环境同样具有影响。值得注意的是，性状的预测能力可能依赖于其为适配交互伙伴而演化的前提。此外，局域非生物与生物条件同样至关重要。例如在岛屿环境中，特化且脆弱的物种预计主要分布于山地，而低地物种则应呈现泛化特化的特征且脆弱性更低。我们以安的列斯群岛（Antillean Islands）上的蜂鸟及其蜜源植物为研究对象，对上述预测进行了验证。研究结果显示，在殖民安的列斯群岛之前，大陆起源的祖先蜂鸟类群的性状分化速率更高。与安的列斯群岛内部发生的有限性状演化相一致，局域非生物与生物条件——而非物种性状——与蜂鸟的资源特化程度呈显著相关……