Polymorphism, parallel evolution, and purpose of dewlap hue in Lesser Antillean Dactyloa anoles

Against a background of conservative dewlap hue among Lesser Antillean Dactyloa anoles, within-population polymorphism is present in a Martinique habitat where UV/grey dewlaps are markedly different to the widespread yellow/orange dewlaps. Moreover, parallel evolution on Martinique and St. Vincent of 1) UV/grey dewlaps in similar habitats, and 2) small but consistent differences between dewlap hue in xeric versus montane habitats, imply natural selection. Anole dewlaps are widely thought to have a role in species recognition and potentially act as a pre-mating isolating mechanism, and this is compatible with the degree of genetic isolation in an “ecological speciation” paradigm, but not in an “allopatric speciation” paradigm.