Year: 2013 Page 30 of 37

Anolis fuscoauratus. Photo by Roberto Langstroth

AA reader Roberto Langstroth writes:

Perhaps Anole Annals readers would enjoy these shots of a displaying A. fuscoauratus on the Nassau Plateau of Suriname. The second photo shows some interesting behavior, e.g., the tail curling and the tongue protrusion. There were two individuals involved in vigorous displays…as the third blurry “artistic shot” shows… They were on a vertical trunk of a large tree about 6 meters above ground on a steep slope on the plateau in March 2010.

More On Anole Tail Regeneration

By Jonathan Losos

On March 9, 2013

In Natural History Observations

From Daffodil’s Photo Blog

We’ve had a series of posts on rates of tail regeneration. Daffodil’s Photo Blog, which often features anoles, has just presented a photo tryptych illustrating tail regrowth in green anoles.

Diet Overlap Between Brown Anoles And A Native Lizard In Taiwan

By Jonathan Losos

On March 8, 2013

In New Research

Large prey taken by brown anoles (top two photos) and Swinhoe’s tree lizard (bottom two).

Starting in the 1970s, Caribbean anoles became a model system for studying community ecology, especially interspecific competition. Such studies generally focused only on anole species. Though seemingly chauvinistic, this anolocentrism is reasonable in many localities, where resource competition probably is primarily between anole species (although there was a boisterous debate in the 1980s on the extent to which anoles and insectivorous birds might compete).

However, this is not always the case. In Central and South America, for example, the much greater non-anole saurifauna than on Caribbean islands makes it likely that anoles may experience much greater resource competition with non-anole lizards, as well as other taxa. And the same may be true for anoles introduced to far-flung regions.

Take, for example, the brown anole in Taiwan, which occurs with the native Swinhoe’s tree lizard. Like brown anoles, the agamid is found on the ground and low on tree trunks, and thus might be considered a trunk-ground anole. Being only slightly larger than brown anoles, the tree lizard probably eats much the same food. Gerrut Norval posted a while back on the amazingly large prey that brown anoles and tree lizards eat in Taiwan, and now he and colleagues have published a paper documenting the extensive diet overlap between the species (Gerrut previously provided a post on the background to this study, including some interesting information and photographs on the research methods). Very likely they are strong competitors, although Norval et al. argue that the size discrepancy means that the effect is asymmetric. However, at least in some areas, brown anoles have much higher densities, meaning that their aggregate effect on tree lizards may be just as great as the reverse.

Brown anoles are most dense in hot, open areas, whereas the tree lizards reign supreme in shaded habitats, suggesting that environmental effects mediate the outcome of interspecific interactions between the two species. In addition, this difference indicates that reforestation efforts would be a good conservation move to stem the effect of the brown anole invasion.

Did the Adaptive Radiation of Anoles Happen in Stages?

By Travis Ingram

On March 7, 2013

In New Research

Do events unfold in a predictable sequence when organisms undergo adaptive radiation? Anoles have diversified in many ecologically important characteristics as they have radiated both in the Caribbean and on the mainland. As one of our best-understood cases of extraordinary evolutionary diversification, they make a great system in which to ask how ecological diversity builds up during adaptive radiation.

The idea that anoles radiated in stages dates to at least 1972, when Ernest Williams derived some hypotheses from his observations of Puerto Rican Anolis in particular, drawing upon earlier work by Stanley Rand and Rodolfo Ruibal. Williams noticed that the most closely related species on Puerto Rico tend to belong to the same ecomorph class and occupy similar structural habitats (e.g. branches, trunks or twigs), but occur in different thermal habitats (e.g. closed forests or hot open areas). He proposed that anoles on Puerto Rico diversified first in structural habitat, and later in thermal habitat, a pattern that might scale up to the entire adaptive radiation of Anolis. While this idea has been discussed many times, and helped to inspire more general hypotheses about stages of radiation (e.g. Streelman and Danly 2003), until now it had not been tested using modern analytic techniques that incorporate phylogenetic information for many species.

Figure 11 from Williams (1972), modified to show only the 8 species in the main Puerto Rico radiation.

The Passing Of A Legendary Herpetologist

By Rich Glor

On March 6, 2013

In Anoles and Anolologists in the News

Two days ago, Hobart Smith died at the age of 100. Hobart was among the most prolific herpetologists of all time, with more than 1,500 publications to his name. Included among his publications are several classic monographs such as the Handbook of Lizards (1946) and the Checklist and Key to Amphibians of Mexico (1948). Hobart is the namesake for numerous species of reptiles and amphibians, including Anolis hobartsmithi, an endangered species endemic to the highlands of Chiapas, Mexico. May he rest in peace.

The Dream Of Curt Connors Could Become Real Thanks To A Mexican God

By Ramon E. Martinez-Grimaldo

On March 6, 2013

In Anole Art, Literature, and Humor, New Research

I read a recent news about “The secret to running repairs” and I remembered an older AA post about a hypothetical genetic biologist who researched the ability of certain reptiles to regrow missing limbs, partially to find a way to regrow his own missing arm.

Today, his noble research could be real thanks to a Mexican god. Yeah, the Axolotl, who according to the Aztec myth is a god transformed on a neotenic salamander with the hope that their ability to regenerate body parts will one day help people with amputations.

The Axolotl has become the amphibian prefered by many scientists around the world thanks to its capacity to regenerate both their hurt limbs as well as its jaw, skin, organs and even parts of the brain and the spinal cord. And to top things off, it doesn’t get cancer.

Scientists believe that it will only take a decade or two before the dream of Curt Connors could became a reality: the human limbs could regenerate like the axolotl.

I’m very excited for this news that I believe I forgot the anoles for a little moment.

Jumping Anole Video Goes Viral

By Jonathan Losos

On March 5, 2013

In Anole Videos

httpv://www.youtube.com/watch?v=_bsusAavtOo&feature=youtu.be

Who wouldn’t want to see a lizard do a face plant? Apparently tens of thousands couldn’t pass this one up. It’s all part of Chi-Yun Kuo’s research in the Duncan Irschick Lab; Chi-Yun provided a first-hand account of the research when the paper was published last year.

Editor’s Correction: Chi-Yun’s paper is fabulous, but this video actually comes from Casey Gilman’s also wonderful research. See her original paper in the lab that produced this video and the recent field follow-up.

Flexible Perches… Who Cares?

By Casey Gilman

On March 4, 2013

In New Research

httpv://www.youtube.com/watch?v=5Yk4szOOaFg

I had spent a summer in Florida watching green and brown anoles jump around on trunks and branches, and I was amazed by how well they appeared to navigate their habitat, despite the variable flexibility and complexity of the habitat. Many anole species jump. They jump to move around their habitat, to forage, to fight, to chase (or be chased by) potential mates, and to avoid predators. If you have observed anoles jumping in the wild, you might notice that some species jump a lot, and they jump to and from a lot of different types of structures (the ground, trunks, branches, leaves). While the diameter of different types of structures has been shown to affect running speed and surefootedness, it has also been shown to have little impact on jumping, at least in the lab. But what about the flexibility (compliance) of the structures they are jumping to and from? Will a narrow branch in the wild affect jumping performance, not because of its diameter, but because narrow branches tend to be flexible? What about other flexible structures in nature, such as leaves, which tend to be wide and highly flexible? And, are anoles choosy about where, and from what, they jump?

It turns out, when it comes to jumping, perch flexibility is quite important.

With the help of my advisor, an engineer, and a generous collaborator who gave me guidance and let me use his specially-designed anole jumping tank, we conducted a lab study to to determine if and how perch flexibility affects jump performance in green anoles. We found that the more flexible a perch was, the more it negatively affected jump distance and jump speed. We also observed that the recoiling perches whacked the anoles in the tail as they were jumping, which caused many anoles to do an impressive faceplant (this part of the story has received a bit of notoriety, both in the Annals (twice) and elsewhere). So, increased perch flexibility decreases jumping performance in the lab. But what does this mean for those anoles I’ve seen jumping from leaves and twigs in their natural habitat?

Male green anole perched on a flexible palm leaflet

To answer this question, I headed back down to Florida and spent a little over a month filming green anole jumping behavior. The green anoles I observed in the wild appeared to be extremely choosy about which structures they jump from. While I found them basking and foraging on a range of perches, from stiff trunks to highly flexible leaves, the lizards would generally jump from the sturdiest perches in the habitat. If they were on a thin and flexible palm leaflet, they would move closer to the base of the leaflet to a stiffer spot before jumping. And when they did jump from highly flexible perches, they jumped to another perch that was just a short distance away. The longest jumps we observed were from the most sturdy (and low-lying) perches.

The green anoles I observed appeared to be so good at choosing perches to jump from, that over the course of my study I only noted two failed jumps from flexible perches. In one instance, a male was perching near the end of a leaflet, then moved to a sturdier part of the leaflet to jump onto a perch above him. Although this part of the leaflet was sturdy, it was not sturdy enough. The force of the jump pushed the jump perch down away from him, and he was unable to jump high enough to reach his intended perch. Luckily, he was able to catch onto another leaflet before he hit the ground. In the other instance, another male attempted a jump to a far perch and landed on the ground instead, then quickly climbed back up the palm. However, because I documented undisturbed behavior, many of the jumps I witnessed were sub-maximal. The lizards were jumping as far as they needed to at the time to get to another perch, but were not attempting to flee and therefore may not have been jumping as far as they might otherwise been able to. I wonder how my observations of how choosy they are with jump perches would change if they were in situations where they needed to escape quickly.

Anole Consumption By West Indian Snakes

By Jonathan Losos

On March 3, 2013

In Natural History Observations

Caicos Dwarf Boa (Tropidophis greenway) eating an Anolis scriptus. Photo by Matthew Niemiller.

Neotropical snake and Caribbean expert Bob Henderson writes: “In going over some prey data for a chapter on diet and foraging in species of Corallus and the dramatic dichotomy between West Indian and mainland Corallus, I came up with some numbers you might find interesting.

I recovered 970 vertebrate prey items from West Indian snakes. Of those, 559 (57.6%) were anoles. The next closest prey genus was Eleutherodactylus (129; 13.3%).

Among ground dwelling or largely ground-dwelling species (tropes, colubrids, dipsadids), anoles accounted for 54.1% of their prey. Among arboreal snakes (Corallus, Hispaniolan Epicrates, and Uromacer), anoles accounted for 64.1%.

I suspect there are very few West Indian macrostomatan snakes that do not include anoles in their diets at some time during their lives.”

Amazing Green Anole Battle In Hawaii

By Jonathan Losos

On March 2, 2013

In Natural History Observations

Don McLeish has photo-documented an amazing battle between two green anoles in his backyard. The fight went on for at least an hour, and when he checked in on the lizards at night, one was still breathing hard hours later. Check out the photos!