Sexual dimorphism–differences between the sexes–have been greatly studied in anoles, and so has dewlap color and patterning. But little research has been directed to the phenomenon of sexual differences in dewlap color or pattern. Such differences are relatively rare in Caribbean islands, but much more common in mainland species. Why does this occur? Nobody knows. In fact, what female anoles use their dewlaps for has been little studied (another phenomenon, fodder for a future post, is differences in the size of the dewlap between the sexes, which can be quite substantial).
In any case, here’s a sampling of dimorphic dewlaps.
Anolis fitchi (female and male), and Anolis orcesi (female and male)
Anolis lyra, female on left (photos courtesy Fernando Ayala).
Anolis fowleri, as documented by Dan Scantlebury here.
And a recent post has just discussed this phenomenon in Venezuelan anoles, such as this one.