Female Anolis polylepis. Photo from http://www.wildherps.com/species/A.polylepis.html
In many species of anoles, females within a population exhibit sometimes strikingly different back patterns. A recent paper showed that there is interesting variation in the incidence of such variation: mainland and Lesser Antillean anoles exhibit it much more than Greater Antillean anoles, and within regions, some clades are more polymorphic than others. Although closely related species tend to be similar, this trait has been evolutionarily labile, evolving an estimated 28 times.
The occurrence of this variation raises the question: what’s it for? The most detailed study of the question was Schoener and Schoener’s examination of female polymorphism in Anolis sagrei in the Bahamas. By looking both within and between populations, they concluded that this polymorphism was related to crypsis. In particular, females with stripes tend to occur on narrow diameter branches, where the stripes help them blend in. Calsbeek and Cox have more recently examined the same species, finding most recently that different patterns don’t seem to vary in fitness, though they did not examine whether females with different patterns occurred in different parts of the microhabitat.
The only other recent work on this topic was conducted on A. polylepis in Costa Rica by Steffen.