The Sunday night poster session at JMIH 2011 had a few more anole offerings. Melissa Moody from Iowa State reported on a laboratory experiment on the developmental and fitness consequences of varying Anolis sagrei egg incubation temperature and humidity. Anolis sagrei eggs seem relatively robust to the variation experienced during this experiment. Paul Cupp of Eastern Kentucky University asked whether ground skinks (Scincella lateralis) and green anoles (Anolis carolinensis) could detect chemical deposits from the Eastern Milk Snakes (Lampropeltis triangulum); he found evidence that the skinks could detect these deposits while the anoles could not. Finally, Mingna Zhuang discussed comparative gliding performance of Anolis carolinensis and Anolis sagrei. She found that A. carolinensis is a considerably better glider, perhaps due to the fact that it has a flatter gliding posture than A. sagrei.
Tag: Anolis sagrei Page 4 of 5
Not an anole, but plays one on TV. Photo from Dust Tracks on the Web (http://dusttracks.com/)
Janson Jones is at it again. Having just driven about as cross-continent as you can get, from Alaska to the Florida Keys, he is now waxing eloquent on the lizards of that delightful island string. Today’s post is about introduced green iguanas, which apparently are everywhere and spreading, but yesterday he posted twice, on brown anoles (A. sagrei) and bark anoles (A. distichus) , with some keen observations on interactions between the two. Most notably, he’s noticed on multiple occasions that the larger browns chase off the the daintier barks.
postscript: Just as I hit the “post” button, Jones put up another of his own, with further observations on bark anoles and outlining what would make an excellent Ph.D. dissertation project. Plus, this intriguing observation:
“…the iPad of anoles in the Florida Keys. They’re right on the edge, living in the third space, transitory ground between the browns on the ground and the greens in the trees. They’re not iPhones, but they’re not desktops either. Right in the middle — and perhaps drawing business from both sides?”
Bark anole, A. distichus, from Dust Tracks on the Web
Anolis cristatellus in Miami. Photo by Melissa Losos
In his spare time, photographer and film-maker extraordinaire Neil Losin doubles as a graduate student studying the ecological interactions between introduced trunk-ground anoles A. sagrei and A. cristatellus in Miami. He’s just begun his third field season, and you can read all about it here.
Anolis sagrei from near one of Dan Warner's field sites. Photo by Aaron Reedy.
American Society of Naturalists’ Young Investigator Award winner Dan Warner presented a marvelous synthesis of studies of how external influences affect phenotype and survival in eggs and offspring of lizards and turtles. Among other things, he has demonstrated
that some types of plasticity are adaptive: in temperature sensitive sex determining lizards, males are produced at temperatures at which the fitness of male offspring is greater than that of females, and vice-versa.
Staniel Cay is one of the quaint Caribbean backwaters, populated by yachtsmen, expats, scalawags, locals and…scientists. For more than 30 years, Tom Schoener, David Spiller and associates have worked here, producing a series of textbook studies on food web ecology (most recently here).
Having finished our work in Marsh Harbour, we have relocated to Staniel, marking a return for me after a 19 year absence. As our plane wended its way down the Exuma
- Headin’ south down the Exumas.
chain, the memories of my previous visits and their results came flooding back. While a graduate student in the 80’s, I read Schoener and Schoener’s 1983 Nature paper reporting the results of introductions of brown anoles (A. sagrei) to very small islands (approx. the size of a baseball diamond) around Staniel Cay. S&S, noting that islands of this size do not normally harbor anoles, decided to introduce lizards to watch the populations wither away, and thus learn something about the process of extinction. But to their surprise, the populations did not go quietly into the night. Instead, they thrived and some downright exploded in numbers, one island going from 10 introduced lizards to 98 the next year.
“Are you sure you don’t want to take a lizard pole?” – “No way, we’re on vacation, not field work”.
teasing me
But once arrived on the lovely Yucatan Peninsula in Mexico I just couldn’t get any of the anoles perching on about every single palm tree to dewlap for me. I’d speculate about their dewlap colours – they did look like A. sagrei, but how could I be sure without flipping out their dewlap? And if I did, would it be red or orange, and how broad would the yellow margin be?
It was as if they were mocking me with their presence, knowing that I was pole-less. On the next trip to the local supermarket, however, I saw and immediately grabbed a small package that read: “Fish pen, as seen on TV.” It was a tiny telescopic fishing pole, complete with hooks, reel and line, that can clip to your shirt like a pen. For MXP 200 (ca. $20), I just had to buy it. Although I wouldn’t recommend to hunt any large or skittish lizards with it (it’s a short pole), it proved to be quite effective to satisfy any spontaneous dewlap-flipping cravings during vacation.
The knight anole, Anolis equestris, gets around more than you might think. Photo by Neil Losin.
A new, two-volume set on the conservation of Caribbean herps has just been published. More on that in a minute, but let’s cut to the important stuff. There’s a great summary of the record of anole introductions (discussed previously a number of times on Anole Annals, such as here, here, here and here) in an article by Bob Powell and others. Here’s what they have to say about anoles:
“Anoles (family Polychrotidae). Anoles are highly diverse (Losos, 2009), quite adaptable, and often function as human commensals. Many species in the region exploit buildings, ornamental plants, and the night-light niche (e.g., Henderson and Powell, 2001, 2009; Perry et al., 2008; Powell and Henderson, 2008). Some are colorful and available in the pet trade (e.g., Kraus, 2009), but nearly all introductions within our region were inadvertent and attributable to stowaways in cargo such as building materials and ornamental plants.
Anolis cristatellus is native to the Puerto Rico Bank and was the only anole that made the list of most successful colonizing species (Bomford et al., 2009).
- The Lizard Keeper’s Handbook. p 101
In his book, The Lizard Keeper’s Handbook (1997. Advanced Vivarium Stystems, Inc.), Philippe de Vosjoli explains at length how to select prey items of appropriate sizes to feed to pet lizards. I agree 100% with what he wrote. However, I must say that not all lizards apply these rules under natural conditions (I guess they were absent from class on the day that lesson was taught). Here are some photographs I took of brown anoles and Swinhoe’s tree lizards in my study area that preyed on prey items that most certainly did not fall within the ideal prey size categories.
1. An Anolis sagrei male with a large caterpillar.
2. An Anolis sagrei female with the remains of a grasshopper that she had had in her mouth when we captured her.
3. A Japalura swinhonis female that rushed in to grab a beetle grub that was exposed when we accidentally knocked over a dead betelnut palm (Areca catecha) in our study area.
4. A Japalura swinhonis male that captured an adult Clanis bilineata in the secondary forest in our study area.
And I believe that anyone who works with the brown anole (Anolis sagrei) would agree with me that these lizards can do some truly amazing things, as can be seen from the photos above. One of the most mind-boggling things I have found in the stomach contents of some of these lizards are centipedes. On one occasion I found a 43 mm long Chinese red-headed centipede (Scolopendra subspinipes mutilans) in the stomach of a brown anole male (SVL = 54 mm). Not only was the prey almost as long as the body length of the predator, but centipedes are venomous. It takes guts to take on such a meal!
From Dust Tracks on the Web
In a recent post, AA mentioned Janson Jones’ (Dust Tracks on the Web) report on catching a magnificent knight anole. Turns out that Jones is not only a kindred spirit, but a keen observer and an excellent photographer. Over the course of the last few days, he has posted a series of stories of observations of Florida anoles that are worth checking out.
Just a few comments. In “Clash of the Anole Titans” (photo above), he tells of a territorial battle between two male green anoles. Ultimately, the fight concludes when one male loses his grip and falls to the ground. Those who study the functional capabilities of anoles are always surprised at the great sticking ability of the anole toepad, much greater than is needed to support the lizard’s body weight (anoles can hang from a single toe!). Perhaps this ability has evolved, not for every day living, but for exceptional circumstances, such as prolonged, hand-to-hand combat or hanging on to a mini-van.
- 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.