I’ve just arrived in Limon, a port town on the Caribbean coast of Costa Rica, to track the spread of the introduced species A. cristatellus. Several realizations occurred to me as we wended our way down the mostly beautiful road from San Jose. First, I realized that not only have I seen cristatellus in its native range of Puerto Rico and the Virgin Islands, but I’ve also seen introduced populations in Miami and the Dominican Republic, as well as here. This species gets around!
Second, I remembered that this is a return to Limon, which I first visited 25 years ago on the second night of my graduate OTS course. And the next morning, I remember walking in the square across from our hotel and seeing cristatellus, a fond reminder of my undergraduate days when I had conducted my honor’s thesis project on anole behavior. I was then at the end of my second year in graduate school, still floundering with regard to what I would do for my thesis, as just before I had left for the course, my most recent idea, studying geographic variation in diet and foraging behavior of collared lizards, had gone up in flames as a result of desert drought in southern California. This was about the 12th failed thesis idea of mine, and I was considering panicking. Little did I know that the anoles I glimpsed on this eight-week course would get my wheels turning and that the idea for my Ph.D. thesis would come to me in one of those lightbulb moments while at the La Selva Field Station.
But I digress. I’m here to see how far cristatellus has spread. This species has been here since at least 1970—how and why it was introduced, I have no idea. I’d like to see if it has spread much up and down the coast, as well as inland, and am wondering whether it is escaping human habitations and entering natural environments. If it is, then it will be interesting to see how it interacts with the native anole fauna. There aren’t many anoles like cristatellus here. Most of the species found near the ground—cristatellus is a trunk-ground anole—are relatively slight in build, and one might think that cristatellus would have them for lunch—literally. This is a stocky, muscular, aggressive species, and the possibility exists that it could have strong effects on the native anole fauna. But the first step is getting an idea how far it has expanded its range.
My friend Greg Mayer reported at the anole symposium in 2009 on cristatellus in Coahuita, a bit south of here on the coast. You can see his Anolis Newsletter contribution here. First stop will be to head down there to poke around. On the drive in, we found cristatellus at Turrialba, about 90 km west and at ca. 700 m elevation, confirming reports summarized by Mayer; this is probably the furthest inland and highest elevation from which the species is currently known here. Several other stops failed to find cristatellus (though I did find a lovely biporcatus in a roadside bar’s garden). We’ll check again at sites en route on the way back. More as the story develops!