Adaptive and non-adaptive convergent evolution in feather reflectance of California Channel Islands songbirds.

ABSTRACT: Convergent evolution is widely regarded as a signature of adaptation. However, testing the adaptive consequences of convergent phenotypes is challenging, making it difficult to exclude non-adaptive explanations for convergence. Here, we combined feather reflectance spectra and phenotypic trajectory analyses with visual and thermoregulatory modelling to test the adaptive significance of dark plumage in songbirds of the California Channel Islands. By evolving dark dorsal plumage, island birds are generally less conspicuous to visual-hunting raptors in the island environment than mainland birds. Dark dorsal plumage also reduces the energetic demands associated with maintaining homeothermy in the cool island climate. We also found an unexpected pattern of convergence, wherein the most divergen

SUBMITTER: Porter CK 

PROVIDER: S-EPMC10646447 | biostudies-literature | 2023 Nov

REPOSITORIES: biostudies-literature