No evidence of genetic differentiation between anoles with different dewlap color patterns

Color variation across and within populations can play an important role in speciation and our understanding of the maintenance of genetic variation. Trait polymorphisms may be important in reproductive isolation and speciation. Conversely, if 2 morphs exist within a species, then the classical question of how the polymorphism is maintained in the face of drift and selection becomes relevant. In Anolis lizards, variations in dewlap size and color are often used as diagnostic markers of species and considered important traits in population divergence and speciation. The aim of this study was to describe dewlap color pattern variation in Anolis apletophallus and estimate gene flow between populations that have different dewlap color patterns. We confirmed that 2 dewlap morphs exist, a "solid" morph that has an orange dewlap and a "basal" morph that has a white dewlap with an orange basal spot. Throughout most of A. apletophallus' range, the morphs have nonoverlapping distributions, except for one area where both morphs occur in equal frequencies. Analysis of reflectance spectra demonstrated that the color of the dewlap margin differed between morphs but that dewlap color and pattern did not differ across populations within morphs. Using 8 microsatellite markers, we found little genetic differentiation between populations or individuals with different dewlap morphs. In contrast, the small amount of genetic structure that does exist is due to current day geographic barriers. Therefore, dewlap color variation in A. apletophallus appears to be a polymorphism rather than an indicator of 2 fully or partially reproductively isolated populations.