Year: 2012 Page 36 of 47

The Bay Islands proper consist of a crescent of four land-bridge islands lying approximately 50 km off the northern coast of Honduras in the Caribbean Sea. About halfway between those islands and the coast lies a smaller sub-archipelago, known as the Cayos Cochinos (or ‘Hog Islands’), which consist of two larger islands (Cayo Mayor and Cayo Menor) and 13 smaller cays (see the map below). The Cayos Cochinos are famous in the commercial reptile trade for their endemic populations of insular-dwarf ‘pink’ boa constrictors.

The Bay Islands and Cayos Cochinos of Honduras. For scale, Cayo Menor and Cayo Mayor are about 3 km apart. Adapted from Green (2010).

I’ve had the pleasure of conducting herpetological research in the Bay Islands since 2007 thanks to support from a UK-based conservation organization called Operation Wallacea, and a generous team of researchers (Chad Montgomery, Bob Reed, Scott Boback, Steve Green, and Tony Frazier) that have been working on the boa and Ctenosaura populations there for several years, and were nice enough to get me involved. And while the Bay Islands have gained some notoriety for their exotic snakes, another local squamate has gone (almost) entirely unnoticed. I’m alluding to, of course, the anoles. In 2007, when I was helping Chad Montgomery with his Ctenosaura melanosterna project on Cayo Menor, I began to notice just how abundant the anoles on that island were. The little guys seemed to be on almost every tree in the interior of the island. After asking around and doing a few literature searches, I started to realize just how untouched, and potentially interesting, this system really was.

Two anole species occur in the Cayos Cochinos, Anolis lemurinus and Anolis allisoni.

A Changing Climate – The Birth of Biophysical Ecology and Modern Reptile Thermobiology

By Martha Muñoz

On April 15, 2012

In Classics from the Literature

Anolis armouri basking on a rock.

Our era of human-mediated climate change has brought startling new realities that we must face – ocean acidification, desertification, and receding ice caps, among others. For those of us who study lizards, one message is pervasive and clear – many species are being pushed to their thermal limit, and it is likely that many lizards, especially those that prefer cooler temperatures, won’t be able to take the heat. But, how do we know this? One of the main methods used to determine how reptiles will respond to climate change is to compare their preferred temperature (i.e., where lizards would like to keep their body temperature, given the option) to a random sampling of the thermal environment.

From a lizard’s eye view, though, the thermal environment is more complex than just air temperature. Lizards have volume, shape, and color, all of which affect their core temperature. Essentially, the operative temperature (Te) describes a lizard’s thermal environment as the sum total of many different interactions, such as radiation and convection, among others. Because it describes how temperature is shaped by everything except behavior and physiology, the operative temperature essentially describes how a perfect thermoconformer instantaneously perceives the environment. As such, it has been used as the null hypothesis for behavioral thermoregulation – if we can describe the thermal environment by recording Te, then we can use field-measured body temperature to determine the degree to which animals are thermoregulating. Here on the Anole Annals I’ve considered how devices have evolved to capture the operative temperature. The earliest prototype was a water-filled beer can, and we now have copper models painted to match the organism’s reflectance and HOBO devices.

Copper models of Anolis cybotes in the making.

But just where did these devices come from? I’ve been in Terre Haute, Indiana working with Dr. George Bakken at Indiana State University for the past two weeks making copper models of Anolis cybotes for my field research in the Dominican Republic. Dr. Bakken, along with Dr. David Gates, operationalized the term “operative temperature” for the ecological community in a seminal 1975 paper. I sat down with Dr. Bakken for an interview to learn how the intellectual climate promoted this and other important foundational works for biophysical ecology and reptilian thermobiology.

Sighting Of The Gray-Dewlapped Anolis Carolinensis

By Jonathan Losos

On April 14, 2012

In Natural History Observations

The fabled gray dewlapped anole. Photo by Harry Greene

Harry Greene and Jed Sparks lead a two week graduate field trip to Florida. While there, they espied the lizard shown above in the Corkscrew Swamp near Naples, FL. Here’s what Harry had to say: “Jed Sparks, the other instructor, initially said “green” after I’d told him to expect pink, and that was the first of the two we saw–I got only a glimpse of the partly protracted dewlap and no photos of that one. Second animal I got 3-4 images of separate dewlap expansions, and can say that through binos they looked pale green, but when I look at the images I see white scales and gray or green interscalar skin, not sure which! In any case, I can tell you almost exactly where I saw each of them, and they were on the same first half stretch of the ~2 mi boardwalk, in each case in well lit sites on the outer edge of swamp proper.”

Note that Macedonia in his 2003 paper referred to the dewlaps of these species as “greenish-gray.” Gray-dewlapped green anoles are known from southwestern Florida, but have been little studied. The seminal work is Macedonia’s aforementioned study, that concludes:

Sizing Up Green Anole Dewlaps

By Simon Lailvaux

On April 13, 2012

In New Research

Several years ago I was involved in a study showing that the dewlaps of individual male green anoles change size over the course of a breeding season, increasing in area from winter to spring and then shrinking from spring to winter. This result was first noted in the field and verified in the lab, and is not a statistical artefact – individual dewlaps really do change size!

Shortly after that study appeared I found myself in Australia doing postdoc work on crickets. During that time I gained an appreciation for life-history and the battery of approaches, ranging from artificial diets to mating schedule manipulations, which researchers use to expose resource allocation priorities in animals. (On a related note, I also gained an allergy to crickets). When I returned to the lizard world I started thinking about dewlaps and resource allocation, and I wondered if it might be possible to apply some of these life-history techniques to anoles to figure out the mechanisms underlying the incredible growing/shrinking dewlaps.

It turns out that not only is it possible, it’s actually pretty easy, and my research group was recently able to conduct a simple dietary restriction experiment that yielded some unexpected results. We wanted to test whether dewlap size is affected by resource availability,

Is This Anolis Anoriensis?

By Jonathan Losos

On April 12, 2012

In All Posts

asks reader Esteban Dominguez Vargas, who posted the photo on his Flickr page. For more on A. anoriensis, read here.

Water Loving Green Anoles

By Jonathan Losos

On April 11, 2012

In Natural History Observations

Photo by Janson Jones

We’ve previously discussed how green anoles, Anolis carolinensis, are much more terrestrial in areas where A. sagrei doesn’t occur. Janson Jones, who has written on this previously, now adds a new twist–at one sagrei-less site in Georgia, they’re frolicking around in the water lilies and other aquatic vegetation. Read all about it here.

That got me thinking. Maybe this is how the famed “aquatic” anoles evolve? First you hang out on weeds in the water, next you’re jumping in for a dip?

And speaking of anoles, not only do they float, but they can swim, even those that rarely, if ever, enter the water. I’ve inadvertantly put A. sagrei into the ocean a number of times (think lizard noosing malfunction), and they just press their legs against their body and swim by undulating their tail, alligator-style. Green anoles do that, too, and I’ll bet all anoles innately can swim. I wonder what would happen if you put a crown giant in water. Anyone want to try that with their pet in the bathtub? I bet they can swim, too. So, anoles are pre-adapted (exapted, if you will) for becoming adding aquatic habitats to their repertoire.

And that leads me to one more thought in this ramble: Carl Gans published an obscure paper (Locomotor responses of Calotes to water (Agamidae: Sauria). J. Bombay Natural History Society, vol. 74:361-363, 1977) years ago about some Asian agamid lizards (Calotes) that he dropped into a swimming pool. At first they swam as described above, but then started flailing their legs ineffectually. Eventually, their head would drop below the water, they would breathe in some water, sink to the bottom and then start walking around, presumably until they would have drowned if not rescued. Doesn’t seem like they have much of a future in adapting to aquatic habitats. Similarly, if you dunk a baby duck under water (not that I’ve ever done that), they hold their breath, but baby chickens try to breathe, and things don’t go well. Take home lesson: basic motor patterns and behaviors are needed if a species is to have any hope of adapting to a new habitat. If it doesn’t have the necessary prerequisites to survive there, they have no chance of adapting. (This is, more or less, the theme of another Gans paper I stumbled across when looking for the one mentioned above).

Barbados: Caribbean Herpetofauna Island of the Day

By Yoel Stuart

On April 10, 2012

In Natural History Observations

Postage stamp for Anolis extremus, the Barbados Anole

Although advertisements on the Boston MBTA are trying to convince me that one visits Barbados for its white beaches and plush resorts, I know that the herpetofauna is the real draw!

A Giant’s Snack And As A Snack (itself)

By Miguel Landestoy

On April 8, 2012

In Natural History Observations, Notes from the Field

Even with their large size, and one spending quite some time in their territories, it is somewhat difficult to find a Giant Anole during the day in the Dominican Republic. The most widespread and common species (at least in the Dominican side) is A. baleatus, which is not an unusual sighting at the mesic riparian forest of “Gran Cañada” in the botanical garden of Santo Domingo. But even there, observations are limited by spotting an animal right after it moves to hide away from view (squirreling or slowly sliding around tree trunks). The population in this particular locality seems to be stable and not pursued by people, whom locally have the misbelief that they are aggressive and harmful to humans.

Regarding a local species, A. barahonae, possibly the first encounter I had with this species was back in 2003, in the hills above Enriquillo, southwest of Barahona, where through binoculars, I saw at the distance and high in a large tree a White-necked Crow (Corvus leucognaphalus) holding a large, strong, greenish anoline lizard it its beak. Although I couldn’t see many details of the lizard, I think it must have been A. barahonae because it is the only Giant anole known from that locality. The White-necked Crow forages mainly in flocks and in the canopy, so I suppose that they represent a common predator to that anole species.

After that encounter, I have seen just a few more to date: one basking in a large tree in a shade coffee plantation, also in an epiphyte-packed tree in a cloud forest. This time (yesterday), a fellow local biologist and I were exploring some rivers in the Nizaito watershed, also south west of Barahona. Specificly at a tributary stream that pours into Río Paraiso, while taking photos to a basking Ameiva taeniura aside the road, about 11:00 a.m., I heard some noise coming from a nearby cluster of rather young Cecropia trees. Then my attention was caught by a glimpse of the wing beats of a sphinx moth, soon realizing that it already was in the mouth of a Baoruco Giant Anole. The anole kept still while holding its prey, with tail hanging outwards off the leaf where it was perched.

Unfortunately, I didn’t see the action before the attack happened, but as seen in the pictures, the dead leaf of the Cecropia was probably the perch that the moth used for roosting throughout the day. As most moths are nocturnal in habits, it is likely that it was inmobile siting there just relying in its cryptic coloration and pattern. In an earlier post: A. cuvieri On The Prowl, some excellent photographs by fellow naturalist Father Sanchez showed a Puerto Rican Giant Anole (Anolis cuvieri) deliberately moving about at moderate heights and using several kind of perches. I often imagine that all these anoles would take their prey mostly up in the canopy or high in the tree trunk, but these photographs of the A. barahonae eating this moth were taken at a height of 3 meters, atop of a small tree (Piperaceae) almost overlapping with a taller (8 m) Cecropia tree. Previous to when I heard the sounds coming from the attack, I didn’t notice any motion in the area as I was pretty close. The anole may have been stalking or more likely foraging and scanning this (unusual?) substrate in search of random prey.

Shedding Green Anole Photo

By Jonathan Losos

On April 7, 2012

In Anole Art, Literature, and Humor

Shedding green anole is the Photo of the Day at National Geographic.

The Anoles Of Guadeloupe

By Pierre Legreneur

On April 7, 2012

In Natural History Observations, Notes from the Field

Guadeloupe is composed of two islands whose shape is that of a butterfly and that were joined together in 1806 by the wooden Union Bridge and then the Gabarre Bridge in 1929:

Situated to the west, Basse-Terre has an area of 848 km2. This is a volcanic mountain whose summit is the Soufriere, located at 1467m altitude. It is covered with a dense rainforest with many rivers and waterfalls.
Situated to the east, Grande-Terre has an area of 586 km2. The substrate is limestone and consists of a plain bordered by a mangrove forest in the southwest, an irregular succession of hills called “les Grands Fonds” in the center and an arid plateau of rocky coasts in the north.

The species of endemic Anolis of Guadeloupe is called Anolis marmoratus, with reference to the orange marbling on the head of the specimens described by Dumeril and Bibron in 1837. In fact, Anolis marmoratus is a species which has 6 subspecies of Guadeloupe and six others on the islands around (La Désirade, Petite Terre, Marie Galante, Les Saintes, Les ilets Pigeons, Les Ilets Kahouanne, les Ilets Fajous).

Regarding Anolis marmoratus of Guadeloupe, the subspecies are:

Anolis marmoratus marmoratus

Anolis marmoratus marmoratus, which Lazell in 1962, noted as “the most beautiful anole he never saw.” It lives around Capesterre, at the southeast of Basse-terre. Adult male are apple-green, shading to blue on the tail and yellow-green on the limbs. The head, the neck and the orbital area are marbled with orange, the throat fan orange-yellow with yellow scales. Preliminary work we have conducted suggests that it could be classified as a trunk-ground ecomorph.

Anolis marmoratus girafus

Anolis marmoratus girafus that lives along the west coast of Basse-Terre in the driest area of this island.