Professor of Biology and Director of the Living Earth Collaborative at Washington University in Saint Louis. I've spent my entire professional career studying anoles and have discovered that the more I learn about anoles, the more I realize I don't know.
httpv://www.youtube.com/watch?v=H3KUK0zSnjE&feature=channel&list=UL
For those people who like to watch videos of yule logs burning in a fireplace, the tropical equivalent is this video of Puerto Rican anoles displaying. It features cristatellus, evermanni, pulchellus, krugi, stratulus and gundlachi. A second video on the Fleishman Channel has more displays. And the nice tropical bird soundtrack is very relaxing.
In recent years, a quirky area of research has developed in which researchers measure the length of the second and fourth digits on the hand and foot, calculate the ratio (2d:4d) and then compare this ratio between the sexes. Surprisingly, in many species there are consistent differences between males and females. In mammals, that ratio is smaller for males, whereas in birds, the opposite occurs. But few studies have looked at the other vertebrate classes.
With this in mind, Direnzo and Stynoski recently calculated digit ratios for several common Costa Rica anoles and frogs. The abstract of their paper, published in Anatomical Record last year, tells the story:
“It is now well documented that androgen and estrogen signaling during early development cause a sexual dimorphism in second-to-fourth digit length ratio (2D:4D). It is also well documented that males of mammalian species have a smaller 2D:4D than females. Although there are discrepancies among 2D:4D studies in birds, the consensus is that birds exhibit the opposite pattern with males having a larger 2D:4D than females. The literature currently lacks substantial information regarding the phylogenetic pattern of this trait in amphibians and reptiles. In this study, we examined 2D:4D in two species of frogs (Oophaga pumilio and Craugastor bransfordii) and two species of lizards (Anolis humilis and Anolis limifrons) to determine the existence and the pattern of the sexual dimorphism. Male O. pumilio and C. bransfordii displayed larger 2D:4D than females in at least one of their two forelimbs. Male A. humilis had larger 2D:4D than females in both hindlimbs, but smaller 2D:4D than females in both forelimbs. Male A. limifrons may also have smaller 2D:4D than females in the right forelimb. Finally, digit ratios were sometimes positively related to body length, suggesting allometric growth. Overall, our results support the existence of the 2D:4D sexual dimorphism in amphibians and lizards and add to the knowledge of 2D:4D trait patterning among tetrapods.”
httpv://www.youtube.com/watch?v=sVn-JWEcHAg&feature=player_embedded
We talk a lot about how green anoles and brown anoles interact with each other, and the supposition usually is they are competing for space and/or food. But they can interact in another way, by eating each other! And here’s graphic proof that it happens!
The footage is from the classroom science project run by Aaron Reedy, Dan Warner and Tim Mitchell. We featured their recent paper a few months ago, and you can read all about the project on their website.
Green anoles everywherer in All-America Park. Photo by J. Losos
The International Biogeography Society meeting over, I had part of a day on my hands before leaving Miami. Many opportunities presented themself in the herpetological magnificence that is South Florida, but I couldn’t escape the disappointment in failing to find the Jamaican crown-giant at All-America Park in South Miami two days previous. So into the rental ‘mobile I hopped and quickly traversed the Magic City.
Arriving at the postage-sized park, I immediately ran into South Miami mayor and renowned neuroethologist Philip Stoddard, who happens to live next to the park and keeps an eagle eye on all of its inhabitants. His Honor confirmed that extreme cold of the last several winters had dealt the Jamaican greens a heavy blow, but nonetheless said that he had recently seen several small individuals, indicating that the population was still extant.
A little green like this one was chased by a bark anole. How ignominious! Photo by J. Losos
After accepting a glass of water, I headed into the park on what was a sunny and beautiful day. Anoles (and also peacocks) were extraordinarily abundant, but what caught my attention was the enormous number of green anoles. Those who are concerned that A. carolinensis is disappearing as a result of the introduction of A. sagrei and others need not worry, they’re doing just fine.
Bark and brown anoles were also quite abundant (word has it that Puerto Rican crested anoles are on the move and now are only a few blocks away), and I made several interesting observations,
Holly, the anole chasing, home returning tabby, now a celebrity
Today’s New York Times featured an article on incredible journeys by lost cats, where they cover immense distances to return to their homes. The article is based on a recent story of Holly, who trekked 200 miles from the Daytona Speedway, where she had become separated from her mobile home at an RV park, to her residence in West Palm Beach. This may seem a bit off-topic for Anole Annals and, indeed, it mostly is, but midway through, the article asks how a pampered housecat could be prepared for a life in the Florida wilds, noting ” after all, she spent most of her life as an indoor cat, except for occasionally running outside to chase lizards.” No doubt if she’s chasing lizards around a house in West Palm, those lizards are almost surely brown anoles, with a few green thrown in. Housecat predation on anoles (and other animals, particularly birds) is a serious matter, but at least it leads to the occasional heartwarming story. Incidentally, the article also refers to the KittyCam project we posted on a while back, in which researchers put little video cameras around the neck of housecats to see where they went, and found all kinds of unexpected surprises, including a couple of two-timing housecats with a second home on the side.
An AA reader writes: “Last night I dreamed about you and the anole annals. You had announced that you were seeking discounts at hotel chains for anole workers and said that you’d arranged a 10% discount for anole workers at Best Westerns.”
Is the truth stranger in fiction? Will the discount really be 20%? We’ll soon be producing the Anole Annals subscriber discount cards. Stay tuned for details.
Green anole, emerging on the experimental scene. Photo by Justin Walguarnery.
They really are small. Photo by Justin Walguarnery
In their rate of heating and cooling. A recent paper by Walguarnery et al. reveals that baby green and brown anoles change temperatures at a remarkably rapid rate, much higher than that reported for most other vertebrates and comparable to that of insects. The reason would seem to be obvious: they are small, with a large surface-to-volume ratio, and thus they gain and lose heat rapidly. Moreover, the typical lizard posture, with body resting on the substrate, enhances the rate of conductive transfer of heat.
Brown anoles, too. Photo by Justin Walguarnery
The authors point out that this finding has interesting implications for our understanding of habitat partitioning between species. In particular, if the body temperature of juvenile anoles very rapidly equilibrates with the operative environmental temperature of the exact spot they occupy, then individuals can very precisely regulate their body temperature, whereas the slower change of larger lizards makes it more difficult to finely adjust body temperatures by moving from one spot to another.
As part of the study, the authors also measured the preferred body temperature of lizards in laboratory gradients and found that juvenile green anoles preferred to be 2 degrees warmer than brown anoles. This result is particularly interesting because previous work on adult lizards had found that brown anoles prefer warmer temperatures. Assuming that this is a real effect and not an artifact of differences between the methodologies of the two studies, this finding raises interesting questions: why do temperature preferences change ontogenetically, and what implications do these changing preferences have for patterns of habitat partitioning? From my own personal experience, adult brown anoles usually appear to occur more frequently in hot and exposed positions than green anoles, and it hasn’t been obvious to me that the habitat use of juveniles of the species is any different, but I have to admit I haven’t paid that much attention to the little fellas. Like anole biology more generally, the thermal ecology of juvenile anoles is a little explored and potentially important area for future research.
But enough of my blathering. Let’s hear what the author, Justin Walguarnery, has to say about the paper:
“The study was conducted as part of a series of investigations into how two of the most widespread Anolis species interact early in life. In particular, we were interested in identifying patterns of behavior and physiological ecology present immediately after hatching. Our goal here was to observe species characteristics defining the fundamental niche that might be constrained, modified, or obscured later in life.
Jason Kolbe’s latest field site
Wonderful as the International Biogeography Society meeting was, there were more important fish to fry in Miami, so several of us played hooky to go looking for introduced anoles. First stop was Miami Beach, where we headed to the famed Fountainebleau Hotel, site of an introduction of A. trinitatis from St. Vincent (note to Wikipedia-adept readers; the entry for the hotel is quite informative, but lacks information on the hotel’s pivotal role in enhancing Miami anole diversity). Last year, Joe Burgess reported that the colony was no more, but we wanted to check for ourselves.
Slipping into the pool area at the back of the hotel, we inconspicuously mingled with the beautiful crowd, gazing up the enormous palm trees and into the bushes, pretending to be looking for birds and lost croquet balls. The morning was semi-sunny, but very windy—not ideal anole weather, especially when looking for a species hailing from near the equator. Nonetheless, when the sun peeked out, we did find the Miami big three—carolinensis, distichus and sagrei—but no sign of trinitatis. After an hour, with the security team moving in, we decamped through the back and headed on.
Next stop: the lush and beautiful grounds of the Fairchild Tropical Botanical Garden, its floral magnificence seemingly designed to provide ideal saurian habitat. We first visited the new Wings of the Tropics building, a lovely, enclosed house full of brilliant eye candy in the form of morpho, postman, and other fabulous butterflies. We stopped in there because word on the street is that the building will soon be re-named Toepads of the Tropics because some uninvited guests have taken up residence in the well-vegetated exhibit, enjoying the sun and the abundant insect fare. Sure enough, we spotted both a brown anole and a female red-headed Agama agama.
Floridian red-headed agama. Photo from dust tracks on the web
“Agama”??? you say? That’s right, these lovely African lizards have taken root in a number of places in southern Miami, amongst them the Fairchild. And in a biomically-appropriate way, these East African lizards are most common in the Old World Xeric exhibit in the gardens, hanging out amongst the Malagasy euphorbs and pachypodia, probably imaging that they’ve just slipped across Mozambique Channel. To complete the illusion, they have taken pains to scare away all the anoles from their rocky redoubt, though we did notice one brave male brown anole in the shade of a rock. Agamas may have the same effect on anoles as do curly-tailed lizards, a suggestion made by James Stroud, who was our very capable tour guide to the lizards of Fairchild.
By then, the sun was out in full force and the anole abundance was extraordinary.
AA contributor and anole breeder extraordinaire Veronika Holáňová and colleagues have just described a new species of Chamaeleolis, Anolis sierramaestrae, from–where else?–the Sierra Maestra of eastern Cuba. The species, described in a paper just published in Acta Societatis Zoologicae Bohemicae, differs in a variety of scalation details from the other five species in this group, and the paper includes a very useful pictorial guide to distinguishing among them.
In addition, check out this nifty x-ray.
Who knows how far this fellow’s genes will spread through Asia?
These pages have chronicled the appearance of the brown anole (Anolis sagrei) in farflung places around the globe, including throughout the Caribbean, Hawaii, Costa Rica, and Taiwan, among others. A new paper in Nature in Singapore reports a first: an established population in mainland Asia, in Singapore. The site of the invasion, and apparently for now the only locality for the population, is a new park, Gardens by the Bay. As Wikipedia reports, Gardens by the Bay is “an integral part of a strategy by the Singapore government to transform Singapore from a “Garden City” to a ‘City in a Garden’. The stated aim is to raise the quality of life by enhancing greenery and flora in the city.” Like many invasive anole populations, this one probably was founded by stowaway lizards or eggs transported in potted plants, but this is just conjecture.
As a sidenote, as far as I am aware, this paper is the first to implement the new Nicholson et al. anole classification, explicitly citing the paper as rationale for referring to the species as Norops sagrei.
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