Ok, this post has nothing to do with Frank Sinatra other than his nickname. But what about blue eyes in anoles? They seem to pop up all over anole phylogeny. For example, in my recent trip to Puerto Rico, three anoles had cerulean peepers–A. evermanni and A. stratulus, which are closely related, and A. gundlachi, which is more phylogenetically distant. And blue eyes occur in other anoles, such as A. etheridgei from Hispaniola.
The observation raises two questions:
1) Just how phylogenetically widespread is the occurrence of blue eyes in anoles? I know I’ve noted blue-eyedness from time to time, but I haven’t get tracked and can’t remember in which species. I propose the Anole Annals community take it upon itself to compile a list of blue-eyed anoles. If you know of one, please post a comment and, even better, add a photo.
2) Why? I can’t believe there is an adaptive significance to having blue eyes per se. Is it genetically linked to some other adaptive trait? Could sexual selection have a role (though I don’t know of sexual dichromatism in eye color)? Other animals exhibit interspecific variation in eye color and I bet there’s a literature trying to explain it, but I’m not familiar with it. Would make an interesting project!
Some quick googling reminded me of a few other examples, below. Who am I missing? And does anyone have a good photo of blue-eyed etheridgei?