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Year: 2011 Page 39 of 42
Julián Velasco and colleagues recently added a new species to the anoles: Anolis anoriensis from the central Andes of Colombia, described in The Herpetological Journal. This species is placed in the aequatorialis group, and appears to be very similar to Anolis eulaemus, another Dactyloa group anole from the central Andes. Anolis anoriensis joins a host of recently described Andean anoles from this clade (e.g., Ayala-Varela and Velasco 2010; Ayala-Varela and Torres-Carvahal 2010 – see New Anole Literature for full citations) and adds to the incredible diversity of anoles in Colombia, which already boasts more recognized species than any other country. Despite these recent descriptions, the relationships of Andean anoles remain extremely poorly known, as does our understanding of the factors responsible for the generation of such diversity.
Anolis anoriensis (top panels) versus Anolis eulaemus (bottom panels), from Velasco et al. 2010
Since Darwin’s time, biologists have believed that evolution occurs at a very slow, glacial scale. A corollary of this belief is that ecologists need not consider evolution as they work out the intricacies of ecosystem functioning—it occurs much too slowly to be a factor in understanding the day-to-day interactions among species and their environment. In recent years, however, it has become apparent that, when natural selection is strong, evolutionary change can occur very quickly. This raises the possibility that ecological interactions can lead to rapid evolutionary change, which could then quickly have ecological effects. For example, several recent studies have shown that fish species will evolve adaptively in response to competitive and predatory interactions, and that these evolutionary changes affect the ecosystem, changing rates of primary production, decomposition and altering the biotic and abiotic composition of the ecosystem. The study of “eco-evolutionary dynamics” is taking off and was recently reviewed by Tom Schoener in Science. In that review, Schoener referred to ongoing research on Anolis sagrei in the Bahamas as an example of how ecological interactions could lead to evolutionary change that would then feedback and alter ecosystem properties (see above).
Although it was filmed a few years ago, I just recently got around to watching the BBC documentary series Life in Cold Blood written and narrated by Sir David Attenborough. In the third episode of the series “Dragons of the Dry” there is a brief segment on anole display behavior. Attenborough aggravates a male A. sagrei with a mirror and is rewarded with “the full works”: erect dorsal and nuchal crests, tail wags, push-ups and dewlaping.
José Ernesto Pérez Villota, a Colombian student, is looking for information on the population structure of A. aequatorialis, or of any other Colombian anole. He is particularly interested if some populations have sex ratios deviating from 1:1. If you have any such information, contact him at jeperezv@gmail.com.
On sale at a website near you
Recently while trolling the internet looking for Anolis grahami to purchase for a research project, I came upon a website offering “wild collected” A. occultus, the Puerto Rican twig anole, and Cuban “false chameleons,” the anoles in the Chamaeleolis clade. Having worked very hard to get collecting and export permits from the Puerto Rican and Cuban officials, I am extremely dubious that such animals could be legally captured and exported for commercial purposes . Although in some cases commercial export permits can be easier to obtain than research permits, I strongly doubt that this is the case in Puerto Rico and Cuba.
I mentioned this to a friend, who pointed me to another website that had a host of difficult-to-obtain anoles for sale, including the Cuban Crown-Giant anole, A. smallwoodi. All the lizards on this website were captive bred. Almost surely, their ancestors were illegally exported from their countries of origin, but apparently the offspring of such animals can be legally bought and sold, which would seem to be a big loophole in wildlife laws. On the other hand, because Australia does not allow export of reptiles for commercial purposes, all of the bearded dragons in the pet trade would be illegal if this were the case.
In any case, I am bemused, delighted, and concerned by this trade in illicit anoles and their apparently licit offspring. Bemused because we jump through lots of hoops to get the necessary permits, whereas others apparently take a different tack. Delighted because apparently there is a big group of anole lovers out there, keeping and breeding these wonderful animals. And, finally, concerned, both because there’s always the threat that too much collecting could jeopardize rare anole species (although I know of no such cases, it’s certainly possible for some rare species), but also because such illegal trade can cause wildlife officials to clamp down on all exporting of lizards, even for valid scientific research. I experienced this myself years ago, when wildlife officials on St. Lucia were very cold and unfriendly and gave us great difficulty. We learned later that a year before, collectors masquerading as scientists, with faked credentials, had gotten permits to export 20 boas, only to sell them. Somehow, the St. Lucians found out, and we paid the consequence.
Imagine my surprise and delight upon entering the Winkleman Gallery last weekend in downtown New York and immediately setting eyes on this piece of art. The Anola Star is part of a new show, Binocular, by Leslie Thornton. Although this work is the only anole, and the only lizard, in the show, there are several images of snakes, as well as other animals. But the exhibition got even better! I walked into a darkened room to discover that the images also had video counterparts. Here’s a snippet of the anole piece, which ran for approximately four minutes and then repeated. Needless to say, this is my kind of art! The show only runs through Saturday, so run, don’t walk, straight downtown to see it before it closes. You can read more about the show and Thornton here, and you can see a review in the New York Times here.
Little blue heron snacks on A. sagrei. Photo copyright bullfrog101, http://www.flickr.com/photos/43104350@N02/4463474718/sizes/l/in/photostream/
In the West Indies and southeastern U.S., the enormous population size of anole species makes them an important component of the ecosystem. In the rainforest of Puerto Rico, for example, the three most common anole species consume an estimated 450,000 insects per hectare. The flip side of this abundance is that anoles—small, not very fast, presumably tasty—may be an important food source for many other species. Indeed, most West Indian snakes eat anoles and, collectively, anoles constitute more than 50% of the diet of West Indian snakes. Similarly, many types of birds will eat anoles at least occasionally (e.g., 40% of the species at one study site in Grenada were observed eating anoles), and some species eat them in large numbers. In addition to birds and snakes, anoles seem to be eaten by just about any flesh-eating animal (or plant) big enough to do so. Other documented predators include many types of lizards (including many instances of cannibalism), dogs, cats, mongooses, frogs, katydids, tarantulas, spiders, whip scorpions, and centipedes (see Lizards in an Evolutionary Tree for citations and further discussion).
Despite the ecosystem importance of anoles, and particularly of predation on them, there is still a lot we don’t know about who eats anoles, when and how. For this reason, field studies are needed, and everyone should be encouraged to document observations they make. For example, a recent post on the “Anolis Lizard” page on Facebook provided a link to a video of a crab eating an unfortunate A. agassizi (itself a remarkable and little known species from Malpelo Island in the Pacific). I am unaware of any previous evidence of crab predation on anoles, and scavenging can be ruled out because the poor lizard is still alive. This situation may be atypical, though, because Malpelo is essentially one big rock, and thus the anoles are always on the ground.
Anolis sagrei amidst the seaweed. Photo courtesy David Spiller.
Traditionally, ecologists have studied food web interactions within particular habitats with the idea that what happens in Vegas stays in Vegas. The idea is that habitats are discrete entities and most ecological interactions occur among species within that habitat, rather than across habitats. In recent years, however, that view has been challenged by the recognition that organisms and resources can cross habitat boundaries. For example, when bears catch migrating salmon, the fish carcasses wash ashore, and the nutrients released from their decay—as well as from the bears pooping in the woods—can link the productivity of the oceans to the terrestrial realm. Increasingly, such cross-habitat/ecosystem interactions are being seen as having major effects on food web functioning.
In a pair of recent papers, the UC-Davis anole team reports elegant field studies on the role that the brown anole, A. sagrei, plays in mediating these effects.
This photograph was taken by a colleague visiting some of Belize’s offshore islands. I’m pretty sure I recognize this species from my time in mainland Belize, but I thought I’d open it up to the community for additional opinions. What species do you think this is?