Some Cool Anole Photos

Not sure how I came across these on the web, but I found Robert Hoogveld’s flickr page and he kindly allowed me to post these fabulous photos. Some may recall the post on Robert’s article on A. proboscis two years ago. Apparently, he has some more good stuff up his sleeves, or so he tells me.

Photo by Robert Hoogveld

Anolis marmoratus. Photo by Robert Hoogveld

 

Photo by Robert Hoogveld.


 

Anolis (Chamaelinorops) barbouri. Photo by Robert Hoogveld.

 

 

 

 

Photo by Robert Hoogveld

Anolis oculatus. Photo by Robert Hoogveld

Marine Subsidies, Washed-up Seaweed, and Insect Damage To Plants: What’s the Role Of Lizards?

Seaweed washed ashore on a Bahamian island. Photo by Dave Spiller.

Ecologists are increasingly recognizing the myriad connections not only among species within an ecosystem, but between species in different ecosystems. Case in point: seaweed often washes ashore, and it affects leaves on the plants found near the shoreline. How’s that, you might ask? Well, the seaweed decays and releases nutrients that act as fertilizer, increasing the growth of land plants. That’s good for the plants, but it also makes their leaves more tasty, and hence plant-eating insects are attracted and cause more damage to the leaves.

That seems straightforward enough, but then it gets more complicated. As the seaweed decays, it attracts lots of insects. And the insects, in turn, attract lizards. And, in fact, if you happen to be studying this process on small islands in the Bahamas, as Jonah Piovia-Scott and a team from UC-Davis were, then those lizards are our favorites, brown anoles. And if there are more brown anoles around, then they’ll eat more of the herbivorous insects that plague the land plants, and so the washed-up seaweed actually decrease the damage to land plant leaves, thanks to the helpful consumption of the anoles.

Except…maybe the lizards will be so delighted by the seaweed that they’ll spend all of their time there, eating the insects on the seaweed, and thus neglecting the insects on the landplants, so now the effect of seaweed on the land plants becomes negative again.

path diagramSo which is it? That’s what Piovia-Scott et al. set out to discover, and they’ve just reported the results in a paper in Oecologia. And the diagram to the left explains it succinctly. Seaweed increases nitrogen in the leaves, which increases herbivory. Seaweed also increases lizard density, which decreases herbivory, though the negative effect isn’t as great as the positive effect of the nitrogen. Moreover, seaweed also causes lizards to shift their diet, which has a small (and statistically non-significant) positive effect on herbivory because the lizards aren’t eating as many of the land plant herbivores. Bottom line: seaweed increases leaf damage; lizards can’t prevent it, in part because their effects are schizophrenic: more lizards, but eating fewer herbivores.

Interestingly, these results are opposite of what the same team of authors found in a study we discussed two years ago. The difference was that in that study, a big pile of seaweed was laid out at one time and the results were followed over a short period, whereas this study followed natural seaweed deposition and compared sites differing in the amount of seaweed washed ashore, following their sites for a lengthier period of time.

One last point: how did the researchers document that the lizards were switching diet? Not from sitting around and watching the lizards, but by measuring the carbon isotope ratios in their tails. Marine vegetation tends to have higher ratios of Carbon-13 than terrestrial sources, and so insects feeding on plants from different areas will, in turn, have different ratios, which means that, in turn, one can look at the Carbon-13 ratios in lizard tissue and get a sense of from which ecosystem they’re deriving their carbon. And in this case, the more seaweed, the higher the ratio. Pretty nifty!

Attempted Predation Of A “Yelping” Cuban Treefrog By A Knight Anolis

This occurred at 10:20 AM April 12, 2004 in South Miami Florida. I was working in my kitchen at my home in South Miami Florida with my back porch door open, when my attention was captured by a loud “yelp-yelp” sound in repetition. I also noticed that I heard the “distress” call of a cardinal – similar to what I would hear if there was a cat or snake in my backyard. I grabbed my Sony cybershot 3.2MP and ran out my back door. On an adjacent pony tail palm (Nolina recurvate) just below the crown, about 8’ off the ground I saw a large knight anole (Anolis equestris) in a head down position. The anole had in its mouth, the back legs (below the knees) of a Cuban treefrog (Osteopilus sepentrionalis). The frog was making a very loud repetitive “yelp-yelp” sound while trying to climb out/away from the lizard’s mouth using its front legs. There were a pair of cardinals and mockingbirds, and a blue jay that were attracted to the sound. The cardinal was calling, and the mockingbird was approaching and slowly opening and moving its wings in a “swimming fashion,” making it obvious as it walked across the ground. The birds’ focus seemed due to the frog’s call. I have never experienced any reaction of a bird to the many resident Knight anoles in my property or elsewhere. I managed to get a short clip (meaning to take an image) and a captured still is what you see attached. After a few more cycles of yelping, the frog managed to break free from the Anolis’ mouth and hopped away behind my AC unit. Having had some firsthand past experience with Osteopilus’s antipredatory compounds, I wondered if they had the same effect on lizard’s bucccal cavity as they did on this (at the time intoxicated) human. I had heard a very similar call from an unidentified tree frog in Costa Rica 1998. It had been captured by a parrot snake (Leptophis sp.) that fell to the ground in front of a friends horse while we were jungle riding in Guanacaste. To humans, the call does sound very much like a baby, or toddler’s wail. I would be interested in knowing if it serves to attract other predators giving the “crier” a possible distracting means of escape.

Glitter Anole

Woo-hoo! Check out these anole beauties. And the green one actually has a red dewlap and looks passably like Anolis carolinensis. Google “plush anole” or “glitter anole” and you can have your own–for as little as eight buckaroos.

But there’s a backstory. Over the years, two undergraduates who worked in my lab each gave me a plush anole as a thank you present when they graduated. One day I was talking on the phone and idly picked up one of the stuffed fellows. Still attached to it was the information tag. And as I opened the tag, which contained natural history information, reasonably accurate, on A. carolinensis, I was amazed to see this:

No doubt, you can see one cause of my amazement. That’s no Carolina green anole, but rather its ecomorphic döppelgánger from Hispaniola, A. chlorocyanus. And, moreover, that’s not just any photo of a Hispaniolan green–that’s my photo! And, as you might have guessed, used without permission.

Incensed, I looked to the bottom of the tag for the company that makes the toy, Fiesta Toys. I looked them up online and went to their contact page. I filled in the little box on the page, noting that they had used my intellectual property without my permission. I pushed “send,” figuring I’d never get any response, much less satisfaction. Continue reading

How Often Do Lizards Capture Enormous Prey? And How Often Are They Unable To Consume It?

The photograph above from Daffodil’s Photo Blog shows a brown anole that has just caught a roach almost as big as itself. The lizard was actually able to run away with its prey, so we don’t know if it was consumed.

This, in turn, reminds us of a previous post of DFB in which a green anole again caught a really large prey item, in that case a moth, but again the outcome was unknown.

Imagine eating a Big Mac 80% of your body weight. Think how long you could run on that, and you’re warm-blooded–lizards have a much lower metabolic rate. How often do anoles get this bonanza? Certainly, most of their prey items are quite tiny in relative terms. And how often do they catch prey that they ultimately can’t ingest? There  is a lot of data on anole diets in the literature, but no one has every synthesized it to see what general messages can be extracted, what broader questions–such as this one–can be addressed. Would make for an interesting project.

Review Of The Giant Dactyloa Anoles Of Panama With Description Of A New Species

 

Anolis ginaelisae

Anolis ginaelisae

Six large anoles of the Dactyloa clade occur in western Panama. In their explorations, Lotzkat and colleagues have collected all of them, and have just published a paper in Zootaxa reviewing these species. Their phylogenetic analyses based both on DNA and morphological characters confirm the existence of the six taxa, but also find geographically-oriented genetic differentiation in two species. In combination with morphological data, the authors split A. microtus into two species, the new one under the name A. ginaelisae.

The paper includes a nice review of all the species including spiffy color plates (see A. ibanezi below as an example) and natural history notes (short take: they’re all arboreal and almost all individuals have been caught at night). A key is also included.

Anolis ibanezi

Anolis ibanezi

One last note. The derivation of the new specific epithet gianaelisae is touching: “Sebastian Lotzkat dedicates this exceptionally beautiful new species to his even more enchanting fiancée Gina Elisa Moog, who has made more than a third of his life worthwhile by now, in deepest gratitude for that wonderful time and pleasant anticipation of a mutual future.”

Abstract: “Six species of giant alpha anoles of the genus Dactyloa are known to occur in western Panama: Dactyloa casildae, D. frenata, D. ibanezi, D. insignis, D. kunayalae, and D. microtus. Based on own material collected along the highlands in Bocas del Toro, Chiriquí, and Veraguas provinces and the Comarca Ngöbe-Buglé of western Panama, we review their variation in morphological characters and the 16S rRNA mitochondrial gene. Our results support all six nominal taxa, but reveal considerable genetic differentiation between populations of the two highland species, D. casildae and D. microtus, respectively, from different localities. Correlated morphological differences confirm the existence of a cryptic species among populations currently assigned to D. microtus, which we describe as Dactyloa ginaelisae sp. nov. We provide point distribution maps, morphology and color descriptions, photographs in life, conservation status assessments, and an identification key for all seven species.”

Brown Anole – Green Anole Interactions

Periodically, we’ve discussed how green and brown anoles interact now that they’ve been thrown into  sympatry in the southeastern U.S. and elsewhere–do they fight, do they mate, do they just ignore each other? Perhaps, it seems, a little bit of each. In any case, the latest report comes from Janson Jones over at Dust tracks on the web, who presents a nice tryptich of observations and photos on a one-side green-brown interaction in southern Georgia. As always, the photos are sumptuous and the text entertaining.

Frog Eats Anole

Brown anole being eaten by a Cuban Treefrog. Photo by jwood10016.

Surely you remember the heart-warming story–the best post AA has ever had–about Gordon, the green anole that was almost eaten by a Cuban tree frog, but somehow escaped and lived to see many more days (if you haven’t, check it out now!). Well, apparently the story doesn’t always end so happily for anole-kind. Above is a photo from Orlando, Fl, of a brown anole going down the hatch, and there’s no reason to believe that it came back up. There’s a whole series of photos on planetisuzoo.

Research Projects Of Anolis lizards In Cuba

Anolis homolechis

From 2009, we have investigated the evolution and ecology of Anolis lizards in Cuba, collaborating with Habana University and The National Museum and Natural History of Cuba. Prof. Losos asked us to describe our research projects in Cuba for communication among anole biologists. Thus, we would like to inform our ongoing projects on Anolis lizards in Cuba, and we are very grateful if you have any suggestions and comments on our projects. Also, your suggestion of collaborating research projects will be welcome.

1. Searching for the genetic basis determining differences in hindlimb length between the trunk-ground anole A. sagrei and the twig anole A. angusticeps. Similar to Sanger et al. (2012), we have tried to determine the developmental timing for divergence of hindlimb length between twig and trunk-ground anoles. The manuscript on this subject was submitted and is now under review.

2.  The effects of microhabitat use, range expansion and the number of speciation events on local species richness of trunk-ground Anolis lizards in Cuba. We examined the species richness and thermal microhabitat partitioning (considered to be a measure of ecological interaction) of 12 trunk-ground anole species in 11 local assemblages in Cuba, covering nearly the entire geographic range of all these species. Our results suggest that the species composition and richness in local assemblages could be explained by both evolutionary history (the number of speciation events and limits to range expansion) and ecological processes (habitat partitioning). This research is a part of Ph.D. thesis of Antonio Cadiz (Tohoku University and Havana University). The manuscript on this subject was accepted by Ecosphere and will be available soon.

3. We reconstructed a phylogeny using almost all Cuban Anolis lizards and also analyzed the genetic distances between populations within Cuban islands for these species. This project aims not only to construct the comprehensive phylogeny, but to understand ecomorph evolution within Cuban island.

4. Genetic basis for adaptation to different thermal environments. Multiple trunk-ground species can coexist since they inhabit different thermal environments. Anolis sagrei was found in open locations with high levels of light intensity and temperature. In contrast, A. allogus was found in shaded locations within forests with low levels of both light and temperature. Anolis homolechis was typically found at the edges of forests or in open locations in forests with intermediate environmental conditions. We try to examine genetic basis for these different thermal adaptation by using both  a candidate gene approach and whole transcriptome analysis.

5. Other research projects will be started this year, although we do not specify the detailed plan.

In addition to Cuban Anoles, we are investigating the evolution of Anolis carolinensis introduced into the Bonin islands (Ogasawara islands) about 50 years ago (from either Guam, Hawaii or Florida).

Masakado Kawata, Graduate School of Life Sciences, Tohoku University, Sendai, Japan (kawata ‘at’ m.tohoku.ac.jp)

Anole Research In Colombia And Venezuela: Scientist At Work Blog Posts

Earlier this spring, I reported on a trip to Colombia and Venezuela to collect natural history data on several unknown anoles: A. heterodermus, A. onca, A. annectens and A. tigrinus. As part of the Scientist at Work: Notes from the Field blog on the Science webpage of the New York Times, I wrote a series of posts, which have now all been published. If you’re interested, links to them are provided below.

Losos, J.B. March 12, 2013. Quest for a little-known suburban lizard. link to article

Losos, J.B. March 14, 2013. Life of a Lizard Wrangler. link to article

Losos, J.B. March 19, 2013. Lizard Olympics. link to article

Losos, J.B. April 2, 2013. A Beach Vacation, Lizard Style. link to article

Losos, J.B. April 11, 2013. An Embarrassment of Anoles. link to article

Losos, J.B. April 25, 2013. A Night of Saurian Spotlighting. link to article

There Is Always Something New To Learn: Lizard Eggs Can Survive Flooding

A close-up of the hatchling, un-hatched egg, and the remains of the hatched egg, we recently reported on.

A close-up of the hatchling, un-hatched egg, and the remains of the hatched egg, we recently reported on.

It is interesting that even in fairly well-studied species, we can still find new information from chance observations and carefully planned empirical studies. Recent studies have found that brown anole (Anolis sagrei) females favor nest sites that are quite moist. Losos et al. (2003) also found that the eggs of this species can survive being inundated for up to six hours by seawater. Recently we reported on an observation of brown anole eggs that remained viable after being inundated by fresh water due to heavy rains. The difference between the two conditions is, since seawater is more saline than the content of the eggs, it can be expected that the eggs would lose water, while when exposed to excessive fresh water the water gains will exceed losses, and the eggs will swell.

The observations of other researchers and ours suggest that the eggs of A. sagrei are fairly tolerant to a wide variety of environmental conditions and can remain viable when exposed (for a few hours) to excessively wet conditions. Our observations in Taiwan also reveal that unless washed away or damaged, the eggs of A. sagrei can remain viable during the high rainfall (often as a result of typhoons) of this region.

As Aristotle (384 BC – 322 BC) said, “In all things of nature there is something of the marvelous.” And I would like to encourage everyone to look into their chance observations and to describe them, not only in chat forums, but also in journals as natural history notes. That way the information is not only disseminated, but may also be accessible to a greater audience and for generations to come.

Brazilian Samba Giant And Anole Biologist Paulo Vanzolini Passes Away At 89

The doyenne of Brazilian herpetology, Paulo Vanzolini died two days ago at an age of 89. Renowned for his herpetological expertise, Vanzolini was even more famous for his samba compositions. Indeed, his Wikipedia page focuses more on his music career and discography than his zoological contributions, an oversight that perhaps Wikipedia-savvy AA readers can rectify.

 

With regard to anoles, Vanzolini made two important contributions in collaboration with Ernest Williams. The first was their monographic treatment of variation in the mostly-Amazonian Anolis chrysolepis species complex, a group that was recently revised by D’Angiolella et al. This monograph was notable not only for its detailed study of geographic variation, but also for its suggestion that speciation may be prompted by climatic cycles that lead to contraction of populations into isolated, allopatric pockets of suitable habitat. This hypothesis was suggested simultaneously and independently of the same suggestion for Amazonian birds by Haffer and led to the influential and much-debated Pleistocene Refugia hypothesis, discussed previously in AA‘s pages.

Vanzolini and Williams had a follow-up paper that is less well-known, but equally insightful and ahead of its time. In this paper, the authors argued that such refuges might be particularly important foci of adaptive evolution and speciation when they disappear entirely. The argument is that populations might be trapped in refuges and as the habitat continues to deteriorate over time, the populations might have no choice but to adapt or perish. In this way, arguing from the chrysolepis complex as well as from other lizards, dry forest or even grassland species might evolve from wet forest ancestors. This hypothesis could explain the existence of closely-related species occupying very different habitats–the antithesis of what is now known as phylogenetic niche conservatism–and even might explain the parapatric distribution of close relatives if the new species expanded its range (see previous post for more discussion). This idea was published in Papéis Avulsos de Zoologia in 1981 .(download it here) and deserves more attention than it has received.

Evolutionary Diversification Of Caribbean Snakes

The Puerto Rican Racer, Alsophis portoricensis. Photo by Donald Gudehus

Sometimes it’s easy to forget that anoles aren’t the only animals in the Caribbean. But, in fact, there are other types, even of reptiles, and some of them have diversified a fair bit (though none, of course, to the extent of anoles). One such group are the alsophiine snakes, formerly all in the genus Alsophis. This Caribbean radiation of racer-like snakes includes at least 43 species ranging in size from 200-2000 mm in length and occupying a variety of habitats.

burbrink et alRecently, Frank Burbrink and colleagues, in a paper in  the Journal of Biogeography, have re-analyzed DNA data originally presented by Hedges et al. and have investigated rates of species, morphological and ecological diversification. The phylogenetic tree they recover is very similar to the Hedges et al. phylogeny and indicates fairly extensive within-island diversification. Sounds very anole-like, but it turns out that rate of diversification is quite different. Unlike anoles, species diversification and the evolution of morphological variety putter along a fairly constant rate (with a few statistical twists and turns).

Why the difference? Burbrink et al. postulate that the opportunity for diversification has been just as great for alsophiines as for anoles, so why are the evolutionary patterns different? The authors put forward a number of possible explanations, but none is compelling. Of course, although adaptive radiations often exhibit explosive bursts of diversification, there is no necessity for this to occur, and some very diverse groups have radiated at a more sedate pace. Moreover, one might question why alsophiines haven’t diversified even more–sure, they differ in body size and climatic niche, but how different are they otherwise? And how many species can co-occur at a given locality? Is it just lack of time–one of Burbrink et al.’s hypotheses–or is something constraining alsophiine diversification?

More generally, it would be interesting to conduct similar analyses on other Caribbean taxa–not just reptiles, but also amphibians, birds, even insects and plants–to see what generalities, if any, characterize Caribbean evolutionary diversification.

True Facts About Chameleons

Anole researcher Anthony Herrel showed his true colors recently in a seminar when he said that chameleons are cooler than anoles. Be that as it may, this video is a fun demonstration of the amazing traits that make chameleons the second coolest lizards. It’s part of the “True Facts” series of videos, which are quite entertaining–one episode on tarsiers was featured in a recent AA post.

Katydid Eats Anole

princeps eating by conehead katydidHere’s a disturbing photo that came across Facebook the other day. And I always thought these katydids seemed like delightful, gentle forest nymphs. Who knew they could be vicious killers. This comes from The Biodiversity Group’s Facebook page, but I couldn’t locate the image on their website, though I didn’t look that hard. They identify the anole as A. princeps but don’t provide any further information.

More Surprises From Anolis Tigrinus

DSC_0054x

Anolis tigrinus. Photo by J. Losos.

I’ve previously posted on the surprising behavior of the Venezuelan A. tigrinus. We found them in astonishing abundance in the town of Colonia Tovar, in the mountains above Caracas. Despite their twig anole appearance and their twig anole habitat use–on twigs and other narrow surfaces–they don’t behave like twig anoles. Rather, they move rapidly and often, and seem to display a lot as well. Some Caribbean twig anoles move frequently, albeit slowly, and some display a lot, but none zip around like these guys. Moreover, we’ve seen a number of other mainland twig anoles, and they live life in the slow, slow, slow lane. So, our first day of tigrinus-watching was full of surprises. But that night, things got even more surprising, as I recently recounted in my most recent post in the Scientist at Work blog of the New York Times..

The tell-tale banded tail.

The tell-tale banded tail.

Anolis tigrinus sleeping on a stem. Photo by J. Losos.

Anolis tigrinus sleeping on a stem. Photo by J. Losos.

As we walked down to the local brewhaus to grab a pizza, we casually scanned our surroundings. And as we walked by a weed patch, there was the tell-tale white blob hanging on to the end of a grass blade. It could be only one thing–an anole. In the Caribbean, this would be primo grass-bush anole habitat, but there were no grass-bush anoles here. Quick examination confirmed that it was an A. tigrinus. That’s right, a twig anole in the grass. And then as we looked around, there were more and more of them–the lot was silly with twig anoles.

The next two days, I came back during the day to look for twig anoles. Unlike in the woods where we had found them initially, the twig anoles here were hard to find during the day, even though the place was full of them at night. The few I saw were deep in the vegetation–my conclusion is that this guys are moving through the vegetation, navigating along narrow branches, stems, and grass-blades.

Which leads, of course, to the question of why in the Caribbean, grass-bush anoles use low-lying narrow vegetation in grassy, bushy  areas, while twig anoles use narrow twigs and branches up in the trees. Perhaps A. tigrinus  is just being opportunistic, taking advantage of an unoccupied habitat and moving in? Certainly a plausible explanation, but I’ve never, ever heard of a twig anole in the grass in the Caribbean. Has anyone? Not even in Jamaica, where there are no grass-bush anoles.

This in turn reminds me of the trunk-crown anoles, A. allisoni, I observed in the grass in Roatan, Honduras. If nothing else, it’s important to remember that anoles are very behaviorally flexible and adaptable. Even though they’ve specialized to different microhabitats, they aren’t so specialized that they can’t use other microhabitats when they get the chance. Crown-giant anoles on the ground are one example, but that’s another story.

In any case, A. tigrinus is a very interesting anole, and it’s great abundance would make it an excellent choice for behavioral and ecological studies.

DSC_0059x

Sweet dreams, little tiger anole. Photo by J. Losos

Nothing Worse Than Being Stuck In The Rain When A Predator’s Around

Anole perch height depending on whether it was raining and whether curly-tailed lizards (Leiocephalus carinatus) were observed on the plot.

Do you like standing out in the rain, especially when it’s cold? Me, neither. But that’s what the dastardly curly-tailed lizard forces brown anoles to do. Any sensible, semi-arboreal lizard would come down from the heights and seek shelter when it starts to rain, and that’s exactly what brown anoles do. Except when they’re in areas of high curly-tailed lizard activity, in which case they suck up and stay up high, shivering and being pelted by rain drops. That’s what research by Marta Lopez-Darias and colleagues (among which, yours truly) reported in a recent paper in Ecology. As the figure below illustrates, pretty much the only time the brown anoles drop down is when the weather goes to pot and curlies aren’t around: cool, windy, and very humid–in other words, when it’s raining. But if big boys have been cruising around on the ground, the anoles maintain their high perches.

Brown anole perch height as a function of a variety of weather variables and of curly-tailed lizard activity (in this figure, instead of presence/absence as in the figure above, predator activity was measured as the time-standardized number of active curly-tailed lizards observed on the plot).

All kidding aside, it’s not clear why they come down when it’s raining, but presumably there’s a benefit to it. One can only speculate what that is; my first guess: when it’s wet and cold, anoles are less able to notice approaching predators and less able to get away quickly because of their lower body temperature, hence they seek safer environs. Or perhaps there’s simply no potential prey afoot, and thus no reason to hang out in a high vantage point looking for them. Whatever the reason for doing so, it appears to be overruled by the threat of marauding curly tails.

As for details of the study: ten study plots were set up in various parts of Great Abaco. Plots were regularly censused, tabulating the number of curly-tailed lizards observed, the perch position of each anole observed, and a battery of meteorological variables.

There Is More To That Beach Anole

Norops-onca-male

Adult male Anolis onca from Isla de Margarita basking.

Continuing the recent interesting post on the Beach Anole Anolis onca, I decided to write something about my personal experiences with this amazing species and attempt to summarize some of what already exists in the literature. Famous by its lack of expanded, smooth, infradigital lamellae, there is a lot more to these beautiful lizard.

Coastal-thorn-scrubland

Typical habitat of Anolis onca on Isla de Margarita

This “beach” anole is basically endemic to Venezuela (it is also found on a narrow portion of adjacent Colombia). Within Venezuela, Anolis onca has a disjunct distribution (more on that below). It ranges continuously along the coast of the states of Zulia and Falcon in the West. It is also found on the islands of La Tortuga and Margarita, as well as along the coast of the state of Sucre in the East. Another, possibly disjunct population has surprisingly been recorded from dry savannas well inland in the state of Monagas! I have observed A. onca in western Venezuela, but I am most familiar with populations from Isla de Margarita. I have traveled countless times to the island and since I was a kid I always remember being fascinated by these fairly large, active anoles. On Isla de Margarita, A. onca is definitely ubiquitous. It is easily found on thorn scrubland, coastal sand-dune environments, and beaches. It is also common around human habitation.  I have always observed this anole in sites with constant and strong wind currents. Several authors have suggested that the windy conditions present in the habitats preferred by this lizard may have prevented it from being strictly arboreal like other anoles (Williams, 1974; Miyata, 1975; Kiester, 1977).

onca-dewlap

These guys have a really large, beautiful dewlap

Whatever the case, it is definitely more terrestrial than other anoles (even species that are commonly found on the ground, e.g. Anolis planiceps) and I have observed it numerous occasions on open ground. However, it often climbs up to about 1.5 m on shrubs, cacti, vines or rocks. Around human habitation it also perches on unfinished walls of buildings, cobble and fence posts (same places frequented by the larger Tropidurus hispidus on the island). I also have observed A. onca on open sand banks of beaches in close proximity to salt water (Ugueto and Rivas, 2010). Williams (1974) also mentioned finding this species near the seashore. Interestingly, light colored specimens are very well camouflaged amidst the sandy soil. I have noticed that when A. onca perches on low shrubbery it often just exposes its head above the leaves. I do not recall seeing such behavior in other anole species.

Most individuals remain motionless when first spotted. If you get too close for comfort, lizards invariably run towards and hide within nearby bushes, clumps of herbaceous vegetation or thorny shrubs. Occasionally they may hide beneath rocks or boulders. Collins (1971) reported that some specimens escape into Ocypode crab holes after lizards were pursued for long time, but I have never observed this behavior. Various types of small arthropods like grasshoppers, robber flies, beetles and spiders have been reported as prey (Roze, 1964; Kiester, 1977; Ugueto and Rivas, 2010). Kiester (1977) reported that the analysis of 38 stomachs revealed that a particular species of chrysomelid beetle constituted a large portion of the diet in western Venezuelan lizards. Saurophagy has also been reported in this species; Miyata (1975) and Kiester (1977) recorded a large individual preying on a female Cnemidophorus lizard in northwestern Venezuela. I observed this species preying on small flies that passed near the lizard on a beach on Isla de Margarita. Kiester (1977), however described a very interesting mode of predation in which the lizard stalked fast moving robber flies in a cat-like fashion using the irregularities of the terrain as cover and dashing towards prey when at close range. What is known about the reproduction of this species is fragmentary at best, but it appears it could be seasonal on northwestern Venezuela. Kiester (1977) reported females laid eggs after the rainy season so that hatchlings come out during January, February and probably March.

Anolis-onca-map

Distribution of Anolis onca and the closely allied Anolis annectens in Venezuela. Notice the disjunct distribution of onca.

As I mentioned earlier, the distribution of A. onca in Venezuela is disjunct and the western and eastern population are separated by a long stretch of apparently suitable habitat. Continue reading

World Turned Upside Down

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Knight anoleYour intrepid correspond is currently in West Palm Beach, Florida, about to embark on a meandering trip north in quest of yellow-dewlapped brown anoles and other anole curiosities (speaking of which, anyone know a good site to find A. sagrei with a lot of yellow in their dewlaps? Like half or more?). In any case, today’s curiosity occurred as I was walking through a large condo development. Out of the corner of my eye, I saw something double surprising. The first surprise was that it was a knight anole–I wasn’t aware that they had spread so far from Miami, although a subsequent google search revealed that, in fact, they are not only known from West Palm, but also from considerably further to the north (see map above).

The second surprise was where the lizard was. It was on the ground. Well, from the corner of my eye, it seemed like it had hopped from the ground, but when I actually turned to look, it was on a tree trunk, about 10 cm off the ground. Still, quite low, not where you expect to find a crown-giant. Sean Giery coincidentally wrote a post about female knight anoles laying their eggs in holes on the ground, so that’s a possible explanation, though this was a little knight, more of a knightlet, at ca. 130 mm svl.

IMG_2120xIMG_2119xExcited by the spotting of such a noble beast, I forsook the brown anoles and began looking for the big greens. And they were remarkably abundant! In about an hour of meandering, I found 13! Some were high up in the tree, right where they should be (you can see the silhouette of one in the photo to the left), but others were much lower (photo on right), and one was on a shuffleboard court (below)! In addition, as I posted recently, evidence of terrestrial habitat use was also found post-mortem by the discovery of a two-dimensional equestris on the one-lane road running through the complex.

Site of the terrestrial knight anole spotting. A careful look will reveal that Anolis equestris isn't the only terrestrial lizard in this habitat.

Site of the terrestrial knight anole spotting. A careful look will reveal that Anolis equestris isn’t the only terrestrial lizard in this habitat.

IMG_2101Why is it that these lizards are on the ground? Well, for one thing, this is not a forest, but a condo subdivsion. There are plenty of trees, but most have been planted and they are spaced out. Many of the knight anoles I found were in trees there were completely isolated, such as the one in the photo on the left.  In other words, to get from one tree to another, or to colonize a tree in the first place, the big lizards have to move on the ground. There’s been very little work on knight anole ecology and habitat use–it would be really interesting to see how often they move from one isolated tree to another.

IMG_2117But these low-riding knights (in the Jansonian sense) are only half of the reason that I’ve titled this post “World Turned Upside Down.” Continue reading