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.
You gotta’ love the cover of the June issue of Mesoamerican Herpetology. The photo is of Anolis insignis photographed at Sector Pocosol del Bosque Eterno de los Niños, Provincia de Alajuela, Costa Rica by Victor Acosta Chaves.
The issue contains new distribution records in Mexico for A. carolinensis, A. sagrei and A. sericeus.
Photo by Patricia Sander from New Orleans, LA.
We’ve had reports of red-headed and orange-headed A. sagrei previously, but here are some new records. Bob Thomas, Director of the Center for Environmental Communication at Loyola University in New Orleans, sent along photos of red heads from both New Orleans (above) and Mississippi (below). If you click on the links to the previous posts, you’ll see that these have been reported far and wide, but we have no idea whether there is any adaptive significance to this stylish look.
Photo by Brad Glorioso from Hancock Co., MS
Photo by D. Burgess
AA’s man in northern Florida, Joe Burgess, went on a special trip to the Riverside section of Jacksonville to nab these pix for our viewing edification. Thanks, Joe!
Photo by D. Burgess
Note added August 26, 2015: Karen Cusick did some sleuthing and discovered that the mural is located on Lomax Street and was painted by Shaun Thurston, who has done many other murals in the city, but none with an anoline theme.
The caption to this photo, which appeared in the Florida Times-Union: the brown anole has overrun Florida. Sometimes called Cuban anoles, they have become the most abundant vertebrate on Florida land.
The Florida Times-Union from Jacksonville published an article today on Florida invasives that arrived from Cuba. Pasted below is what they have to say about our favorite, the brown or festive anole, Anolis sagrei. You’ll have to go to the paper’s website to read about the Cuban brown (or festive?) snail and the Cuban treefrog:
This little lizard has an aggressive streak.
Related: Warming Cuba relations spurs invasive species debate
Swiftly, quietly, the brown anole has overrun Florida. Sometimes called the Cuban anoles, they have become the most abundant vertebrate on Florida land, with recorded populations exceeding 10,000 per hectare.
But really, this is a tale of two lizards. When the brown anole first started to colonize the Florida mainland in the 1940s, it came across another lizard, small and slender just like itself.
The bright green Carolina anole had been the only anole lizard native to Florida, and it had prospered across the Southeast United States. But, suddenly, it found itself in a turf battle with the invading brown anole.
They were both color-changing lizards, between 5 to 8 inches in length, competing for the same territory and the same food. But the brown anole had the upper hand. Back in Cuba, it shared an island with over 60 other anole lizards. It had to bulk up to face its rivals.
“In some sense, it’s better evolved, better adapted to competing with other anoles, so when it gets to Florida, it’s more aggressive and a little bit heavier,” said Yoel Stuart, a post-doctoral researcher in integrative biology at the University of Texas at Austin.
He told the Times-Union that he has heard many native-born Floridians lament the disappearance of the green Carolina anole in recent years, as the brown ones took over.
But all is not lost for the Carolina anole.
Stuart led a study of Carolina and Cuban anoles, and he found that the little green lizards were evolving rapidly to face down the invading force.
For their study, Stuart and his colleagues “battled weather and salt water and malfunctioning motors and leaky boats,” to reach isolated islands on Florida’s Atlantic coast.
They arrived armed with what Stuart describes as “a little extendable fishing pole with a little lasso at the end of it.” And when they spotted a lizard, they tried to slip the lasso around its neck, to collect measurements.
The Cuban anoles had, as expected, settled all but five of the 30 islands they visited. But how quickly the Carolina anoles were reacting surprised the researchers. They had fled to the canopy where, in the course of just 15 years, they had sprouted vastly bigger feet with stickier scales.
“If human height were evolving as fast as these lizards’ toes, the height of an average American man would increase from about 5-foot-9 inches today to about 6-foot-4 inches within 20 generations,” Stuart said in a news release. That would make the average American the same size as a NBA shooting guard.
That rapid evolution will likely allow the Carolina anole to coexist with the brown anole.
“It’s not going to go anywhere,” Stuart said. “It’s just going to be a little less abundant, a little bit higher up in the trees.”
But Stuart sees the brown anole’s rampant success as a warning, especially as other exotic lizards try to make Florida their home. He points out that South Florida is under siege by tegu and monitor lizards.
“People should realize if they buy a pet and can’t keep it, they shouldn’t just release it,” he said. “You never know which one is going to take off and start breeding in the wild.”
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In a recent paper in Life: the Excitement of Biology, Neftalí Ríos-López and colleagues report an observation of a male Anolis gundlachi catching an eating a coqui frog. Here’s the short story–read the paper for more details: “…we observed a male Anolis gundlachi (Yellow-Chinned Anole: SVL 57.1 mm; tail length 88.1 mm) that sprinted down a trunk (8.7 cm diameter at breast height) of a Sierra Palm (Arecales: Araceae: Prestoea acuminata var. montana [Graham] An. Hend. and Galeano, 1996), dived into the leaf litter, and caught an adult E. wightmanae by his head (SVL 22.4 mm; this individual was not calling).”
By coincidence, shortly before seeing this article, we were alerted that Carmen Reyes had posted this photo on Facebook. Here’s her report: “We just went to visit a friend and I saw this lizard with something too big for him in his mouth. I took a closer look but not too close so I can have a better look… and voilà, it was a coqui…First we thought that he had a cockroach. I took the picture and as I got closer, he moved and started climbing the wall, but the coqui fell from his mouth… so I hope that the coqui is alive.
Photo by Carmen Reyes
The gray-dewlapped green anole. Photo by Harry W. Greene
Everyone knows that Florida green anoles have pink dewlaps. However, one population in western Florida has a grayish-green dewlap (see above). Several years ago, AA had two posts on these lizards (1,2). The significance of the gray dewlap remains to be determined. Is this population on the way to becoming a new species?
In a recent paper in Herpetologica, Macedonia and colleagues analyzed the display behavior of the gray-dewlapped population. They found that the gray-dewlappers’ display does differ, though not greatly, from a nearby pink-dewlapped population. However, when they compared their data to yet another pink-dewlapped population, they found that there was greater variation in the displays of the two pink populations than between the gray and pink populations. Thus, it doesn’t seem that the gray-dewlapped population’s behavior is particularly distinctive. What’s up with the gray dewlaps remains to be determined.
Here’s the paper’s abstract:
Green Anoles (Anolis carolinensis) are comprised of red-dewlapped (RD) forms that are found throughout the southeastern USA and a gray-dewlapped (GD) form that is restricted to southwest Florida. Prior research has shown that RD A. carolinensis produce headbob displays of three distinct types that differ primarily in their temporal patterns. Based on known morphological, physiological, and genetic differences between GD and RDpopulations, we hypothesized that these populations also would differ in headbob display structure. To test this hypothesis we quantified 440 displays from 39 males (24 GD and 15 RD) and assigned displays to type using numerical decision criteria. Although comparison of the same display types between GD and RD males revealed differences in the durations of several homologous display units (i.e., bobs or interbob pauses), only one unit differed following statistical correction for multiple comparisons. By taking into account all display variation in both populations simultaneously, however, discriminant function analysis correctly assigned display units with high accuracy to population and display type. Nevertheless, differences in unit durations often were greater between two RD populations occurring within Florida than they were between our GD and RD study populations. Thus, despite our demonstration of differences in the display temporal structure between GD and RD forms of A. carolinensis, these differences appear to be no greater in magnitude than those observed between RD populations.
Photo by Karen Cusick
Karen Cusick recounts this scary encounter on Daffodil’s Photo Blog. The green turned around, to face its impending doom head on.
Photo by Karen Cusick
And then….
In a recent paper in Life: the Excitement of Biology, Ríos-López et al. report observations of predation on a variety of Puerto Rican lizards. Iguanas and Ameiva suffer much of the brunt of predation (including a beagle with a juvenile iguana in its mouth), but reports include A. cristatellus eating both A. pulchellus and A. stratulus (which was subsequently regurgitated–perhaps because it was too large?–and immediately devoured by an Ameiva that ran up to the fallen carcass). In addition, a tody (above) brought an anole back to its nest.
Leo Fleishman and colleagues have just published a cool paper in Functional Ecology, “Why do Anolis dewlaps glow? An analysis of a translucent visual signal.” Co-author Manuel Leal provides the back-story on how the paper–which he refers to as “experimental natural history”–came to be in his lab’s blog, Chipojo lab.
And the New Scientist provides a nice summary of the article in its post: ”
Luminous lizard lotharios ahoy! In the dark undergrowth of the forest, it’s not easy to be seen. Male Anolis lizards use colourful throat fans, called dewlaps, to woo females as well as ward off rivals and predators. But one species has a neat trick to make itself stand out even more – it uses an optical illusion to make its dewlap appear to glow.
The dewlaps are translucent, which means they can transmit as well as reflect light. However, because most objects in the lizards’ environment – such as rocks and tree trunks – simply reflect light, our eyes “expect” them all to appear relatively dull. By transmitting light from the background, the dewlap tricks our eyes – and the eyes of other lizards – into thinking it is actually a light source, says Leo J. Fleishman of Union College in Schenectady, New York, who has studied the lizards for years.
Fleishman’s team was curious to find out why the trick evolved – was the glowing dewlap a way to increase contrast with darker backgrounds or a way to make its colour clearer?
To explore the issue, Fleishman’s team examined the photoreceptors in the lizard’s eyes to work out how they would view the dewlaps. They found that the glow did not create more contrast with the background, which naturally contains other bright spots – where a patch of sunlight passes through the vegetation, for instance. But the glow did significantly reduce the visual overlap, as the lizard’s eyes would experience it, between the throat fans and the colours of natural backgrounds.
The glowing dewlap may be more common than we think. Only a few of some 400 species of Anolis lizards are known to carry the trait, but Fleishman has seen photos suggesting other species’ dewlaps might glow too.
“My guess is that the phenomenon will turn out to be widespread once people start looking, but very few people have looked,” he says.
Here’s the paper’s summary:
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