Anole Annals

Anolis nitens (formerly A. chrysolepis). Photo from http://www.sciencephoto.com/images/download_lo_res.html?id=907650178

Today I had a chat with an evolutionary biologist who specializes on the evolution of tropical forests. We were discussing the effect of climate change on the Amazon, and he first made the point that dire warnings about the Amazon are possibly slightly overstated. Yes, the rainforest may be in big trouble, but it’s not as if the trees will fall down and the area turn into barren desert. Rather, there are many dry-adapted tree species in South America, and they will probably take over, replacing wet forest with dry forest. Conversation then turned to what is known as the Pleistocene Refugia Hypothesis (PRH), the idea that during the ice ages, the climate became drier because so much water was locked up in glaciers. As a result, so the theory goes, rainforests were fragmented as the forest was replaced in many places by other habitats. As a result, a formerly widespread species might become isolated into multiple, unconnected populations. The PRH suggests that these isolated populations often evolved into different species, and the famously high species richness of the Amazon may be a result of high rates of speciation resulting from a series of cycles of forest contraction and expansion. The PRH, however, has fallen on hard times for a variety of reasons, and I think it is safe to say that most workers in the field no longer favor it. Nonetheless, my colleague averred that the hypothesis has been too hastily discarded; in his mind, the idea has been caricatured, and more reasonable versions of the idea have merit and deserve more attention.

Core areas of A. chrysolepis distribution in the Amazon. Map H from Vanzolini and Williams (1970)

Of course, this conversation immediately turned my mind to one thought: anoles! In particular, it reminded me of two significant, yet in recent years little read, papers on Amazonian anoles. The first was a 1970 monograph in Arquivos de Zoologia by Paulo Vanzolini, famed Brazilian herpetologist and samba composer, and Ernest Williams on the pan-Amazonian anole then referred to as A. chrysolepis, now known as A. nitens, and soon to be divided into several species (stay tuned to these pages for more on that as the story develops).

Anole Communal Nests

By Jonathan Losos

On April 26, 2011

In New Research

: An egg of Anolis lionotus. Photo courtesy Edgardo Griffith.

One day, years ago, I was collecting data on the behavior of the Jamaican twig anole, A. valencienni. As I was watching a female, to my surprise, she entered a hole in a tree trunk, and then emerged a little while later. To my amazement, I then saw another valencienni do the same thing! Overcome with curiosity, I approached the tree, peered into the hole, and spied to my astonishment a large number of what seemed to be anole eggs. I was not aware that communal nesting—in which multiple females lay their eggs in the same place—is known in a number of anole species, including A. angusticeps, A. bartschi, A. lucius and A. valencienni. The seminal work on the subject is still Rand’s 1967 Herpetologica paper.

A recent paper adds another species to the list of known communal nesters, the first from Central America of which I’m aware.

Top 10 Gear List

By Yoel Stuart

On April 26, 2011

In Research Methods

The Anolis field season, in the Northern Hemisphere at least, lasts from about mid-April to late-August. As winter finally loosens its grip on 2011, anole biologists everywhere are planning trips, breaking out field kits, shaking out field clothes, and gathering replacement equipment in preparation for another exciting season of Anolis field biology. Thus, be sure to stay tuned to this blog throughout the summer for breaking Anolis news.

In light of the upcoming field season, I’ve compiled a Top-10 list of field gear essential, in my opinion, to Anolis field research. And they are:

Now That’s a Schnoz–New Data on Anolis Maynardi

By Jonathan Losos

On April 24, 2011

In New Research

In the pantheon of anoles, Anolis maynardi has a special place as one of the funniest looking species around. To the casual observer it appears that someone has taken an A. carolinensis (to which A. maynardi is closely related), grabbed it by the tip of the snout, and pulled it forward. The purpose of this pincer-like proboscis, much more extreme in males than in females (which are smaller), is unknown. Indeed, until recently, just about everything about the species was unknown.

Anolis maynardi is endemic to the tiny island of Little Cayman. Remarkably, although visible in the distance, the nearby island of Cayman Brac does not harbor the species. At least naturally. In 1987, A. maynardi was reported at the Cayman Brac airport, most likely a beachhead resulting from a stowaway on an island-hopping airplane. Another survey in 1991 still found it only near the airport, and nothing further was known.

Anolis carolinensis Genome Paper Submitted

By Jonathan Losos

On April 23, 2011

In All Posts

The long awaited paper describing the genome sequencing of Anolis carolinensis was submitted for publication on Thursday. Containing seven figures and with 50 authors, the paper is an epic step forward in our understanding of anole genetics. Stay posted for updates as the story develops.

Now There’s a Book Cover!

By Jonathan Losos

On April 22, 2011

In All Posts

From the back cover: “Anolis lizards have been used in the development and testing of fundamental theories in ecology and evolution, and they have served as important models in behavioral ecology.” The cover photo is credited to Dan Warner.

Man Bites Dog

By Yoel Stuart

On April 21, 2011

In Natural History Observations

We’ve had a number of posts here at Anole Annals about lizards falling prey to snakes. Neil Losin, an anole biologist blogging over at Day’s Edge Productions, tells us a different story. Check it out!

Anole and Orchid Evolution–What Do They Have in Common?

By Jonathan Losos

On April 20, 2011

In All Posts

Figure 1 from Pauw (2006)

Anton Pauw of Stellenbosch University in South Africa writes:

“I am reading Lizards in an Evolutionary Tree and find it fascinating to see how many parallels there are with my one of my study systems, oil-secreting orchids. While the anoles have differentiated across a series of niches provided by a plant, the orchids have differentiated across a series of niches provided by an animal. The orchids segregate the body of the shared pollinator among them so that each places its pollen on a unique segment of the oil-collecting bee. Orchid speciation generally involves shifts between bee species (with placement site conserved), but some speciation also occurs through shift in pollen placement site within the bee , so that sister species occupy for example the first and second segment of the front leg respectively. Anyway, I thought that you too might find these parallels interesting, so I have attached two papers on the topic. I like the comparison of your Fig. 3.2 with Fig. 1 in the attached 2006 paper.”

The other paper is here. Incidentally, apparently no one has posted a picture of an anole sitting on an orchid on the internet.

Vine Snake Bites Off More Than It Can Swallow

By Martha Muñoz

On April 18, 2011

In Natural History Observations

Vine snake tries to chow down on male Anolis longitibialis. Photo: M. Muñoz

Snakes are one of the most important predators of anoles. Recently on this blog, a beautiful series of photos were posted, showing an eyelash pit viper make quick work of an ill-fated Anolis limifrons. This makes sense, right? The viper has a quick strike, a potent dose of venom, and the anole is quite small relative to its predator.

What about when the tables are turned, and the lizard seems the better contender? On a trip to the Dominican Republic I came across a vine snake(Uromacer frenatus), fortunately I had my boots to avoid snake bites. It was trying with all its might to make a meal of an enormous male Anolis longitibialis. This feisty male was at least 7 centimeters in body length and my impression is that the lizard put up a good fight. Although it was dead, its nuchal crest was still raised when I came across this grim spectacle. In Jaragua National Park the habitat is composed of big limestone rocks with lots of nooks and crannies. Male A. longitibialis defend these rocks as their territories, and my guess is that when the snake came knocking, this guy stayed and held his ground. How the puny snake managed to capture and subdue the lizard, however, is still a mystery. I came back a few hours later to check on the snake’s progress and, to my surprise, the snake had completely abandoned the project, leaving the lizard to rot on the rock. It’s possible that my photo snapping had put him off his meal, but I think he may have bitten off more than he could swallow. The snake may have won the battle, but he didn’t win the war. Keep reading to see more pictures of this interesting encounter.

Anoles Respond to Robotic Lizards

By Jonathan Losos

On April 17, 2011

In New Research

: Photo from Partan et al. (2011)

For about a decade now, several researchers have used remarkably realistic looking robotic lizards to study lizard behavior. A pioneer in this approach—especially with regard to studying anoles—is Terry Ord, now at the University of New South Wales. You can see videos of his robotic lizards, as well as clips of a variety of anole species displaying, on the Terry Ord Channel on YouTube (or read about his most recent work here). As you’ll see, these robots are very realistic, both in terms of appearance and motion pattern—they bob, pushup, and extend their dewlap just like a real anole. In fact, even when the rubber body of the lizard hasn’t been attached, the underlying struts move in a clearly anole-like fashion. Bottom line, at a distance, I think most humans would be fooled by a displaying robo-anole. And lizards seem to be fooled, too, because they clearly respond by displaying and approaching the robot—check out the videos and/or Ord’s papers. Or read the recent paper by Partan et al., which demonstrates that A. sagrei responds more to a robot giving the typical signature display than to one presening a different display occasionally given by a lizard in the population.

Just like audio playbacks which revolutionized the study of bird vocal communication, robotic lizards provide the opportunity to rigorously examine lizard behavior in a controlled and replicated manner. Many different questions could be examined, but one of particular interest concerns how anoles distinguish conspecifics from heterospecifics. By altering the display pattern—the timing and amplitude of headbobs, pushups, and dewlap extensions—and by altering the color and pattern of the dewlap, researchers have the ability to understand species-recognition. In turn, such an understanding may provide critical insight into how new species arise, because speciation is the result of changes that lead individuals to no longer recognize each other as conspecifics.