Anolis garmani. Photo by Janson Jones.
Over on phostracks.com: Florida Wildlife, Ecology and More, Janson Jones reports on a very successful trip to Miami that yielded many anoles, most notably the Jamaican crown-giant, Anolis garmani and the Cuban knight anole, Anolis equestris.
Photo by Janson Jones.
Photo by Janson Jones
Janson Jones is at it again. Actually, he’s been at it for a year, but somehow that slipped below our radar. The former purveyor of Dust Tracks on the Web has a new venue, phosTracks.com: florida wildlife, ecology and more.
Like it’s predecessor, phosTracks is full of keen natural history, engagingly presented and complemented by gorgeous photography. And better yet, anoles are one of Jones’ two favorite animals, neck-and-neck (hard as it may be to believe) with watersnakes.
Check out some of Jones’ recent musings on:
Photo by Janson Jones
Photo by Janson Jones
Photo by Janson Jones
and more! Stay on these pages for some of his giant anole goodness coming up soon!
Photo by James Stroud
At JMIH 2016, I chatted with Johanna Wegener, a graduate student at the University of Rhode Island in Jason Kolbe’s lab, about her poster detailing her work identifying hybridization between Anolis carolinensis and A. porcatus in southern Florida.
Interspecific hybridization in anoles is thought to be fairly rare, with the best-known example being hybridization between Anolis carolinensis (native to the southeastern U.S.) and A. porcatus (native to Cuba) in southern Florida. I was surprised to learn how little we know about this rumored hybrid zone.
A. porcatus was likely introduced into Florida within the last few decades, but the striking morphological similarities between A. carolinesis and A. porcatus make anecdotal reports of hybridization hard to confirm. Wegener conducted the first genetic analyses of hybridization between A. carolinesis and A. porcatus. She genotyped 18 nuclear microsatellites from green anoles in Florida (Palm Beach and South Miami) and western Cuba and conducted a STRUCTURE analysis and found support for three genetic clusters consisting of Cuban A. porcatus, and two Floridian groups (one from Palm Beach and one from South Miami). With the addition of the mitochondrial ND2 marker, she found that the South Miami population had both A. carolinensis and A. porcatus haplotypes. Interestingly, there appeared to be very few recent hybrids; instead, the hybrid group appeared distinct from either parent group, suggesting that hybridization has been occurring for several generations.
In addition, Wegener looked at the variation in A. porcatus and A. carolinensis markers in each hybrid individual and found examples of some parent markers being retained at high proportions in the hybrids, possibly suggesting the retention of beneficial parent alleles in the hybrids.
Given that this study was only conducted at two sites in Florida, the exciting next step of this study is to better quantify the genetic makeup of hybrids across southern Florida and map out the hybrid zone.
Figure1. Saddled anole on a fallen tree trunk, Guana Island of the British Virgin Islands.
De Gao and Gad Perry have recently detected the small island effect (SIE) and nestedness patterns of Anolis Lizards of the West Indies. We applied regression-based analyses, including linear regression and piecewise regressions with two (two-slope function and left-horizontal with one threshold function) and three (three-slope function and left-horizontal with two thresholds function) segments, to detect the SIE and then used the Akaike’s information criterion (AIC) as a criterion to select the best model. We used the NODF (a nestedness metric based on overlap and decreasing fill) to quantify nestedness and employed two null models to determine significance. Moreover, a random sampling effort was made to infer about the degree of nestedness at portions of the entire community.
Figure 2. SAR
Figure 3. Nestedness
We found piecewise regression with three segments performed best, suggesting the species–area relationships (SARs) possess three different patterns that resulted from two area thresholds: a first one, delimiting the SIE, and a second one, delimiting evolutionary processes. Moreover, the traditional two-segment piecewise regression method may cause poor estimations for both slope and threshold value of the SIE. Thereby, we suggest previous SIE detection works that conducted by two-segment piecewise regression method, ignoring the possibility of three segments, need to be reanalyzed. Anti-nestedness occurred in the entire system, whereas high degree of nestedness could still occur in portions within the region. So, nestedness may still be applicable to conservation planning at portions even if it is anti-nested at the regional scale.
Curly tail with brown anole tail visible from its mouth
Kayaking to cays
I was recently in Abaco, Bahamas with Losos lab post-doc Oriol LaPiedra and Ph.D. candidate Darío Fernández-Bellon from University College Cork, Ireland, to carry out some behavioral studies of Anolis sagrei on the island and its surrounding small cays. We kayaked (a highly recommended transportation mean for its lesser-impact on the marine ecosystem, not having to rely on the tide schedule, while allowing you to see rays and sharks and sea turtles!) our way out to islands that are known to have A. sagrei naturally existing alone, or with one of their natural predators, Leiocephalus carinatus.
Curly-tailed lizards are known to prey on A. sagrei and can have significant impact on anole behavior and adaptation. Twice I observed Leiocephalus capturing and consuming A. sagrei, one of which was an adult male and the other an adult female. We have also noticed that the A. sagrei on these island tend to perch higher and are seldomly seen on rocks or leveled ground compared to those on islands without curly tails, so this behavior could be an effect of Leiocephalus being present.
A female red-winged blackbird with a A. sagrei in its beak
On a different island where Leiocephalus were absent, A. sagrei are still under predation pressure, this time by red-winged blackbirds nesting on the island. We observed a female blackbird with an A. sagrei in its beak waiting for us to leave the island so that it can feed its chicks. This observation suggests that A. sagrei on islands without Leiocephalus might still be under predation pressure by other species that might not be present on the island at all times. Also, predation pressure exerted by an aerial predator differs from that by a terrestrial predator or if both predators are present, so this might be a factor in morphological or behavioral changes in these lizards on these islands.
Anolis sagrei on one of the small cays
Other interesting observations include A. sagrei density on islands seems to be unintuitive. Some small islands with fewer perches hosted many more adult males and females than large islands did. Sizes of individuals also seem to vary greatly between different islands: small cay A. sagrei seem to be, on average, larger than those on mainland Abaco. Personally, I am unable to note major differences between islands which might have resulted in these observations. I’m excited to see if the data we’ve collected will give more insight into these observations as well as other behavioral results that will come from this study!
One of the few known Anolis roosevelti specimens.
Anole stalwart Greg Mayer gave a wonderful talk discussing the distribution and morphology of the large and maybe-extinct Anolis roosevelti. A. roosevelti, commonly known as the Culebra Island giant anole, was first described in 1931 by Chapman Grant, a US Army Major and practising herpetologist, from a single adult male specimen collected on Culebra. Although Reinhardt and Lutken, in 1863, had already provided an accurate description of A. roosevelti, but under an alternative name of A. velifer.
Reinhardt and Lutken’s specimens were collected from Vieques, Tortola, and St. John, although Greg having the opportunity to study them meant tracking them down to natural history collections in both Copenhagen and Stockholm. In total, this entire species is known from eight specimens, only six of which are still in existence (Greg had the opportunity to study all six, meaning he’s now seen more roosevelti than any other anolologist?). Greg explains that roosevelti based on the limited information provided by Dimas Villanueva, who collected the holotype, and his own investigations, roosevelti can be classified as a “crown-giant” ecomorph. This means that the eastern islands of the Puerto Rico bank had a series of four ecomorphs, with roosevelti being what Ernest Williams termed a climatic vicariant of cuvieri, occuring in (and presumably being adapted to) the more xerophytic forests of the eastern bank islands.
The known distribution of Anolis roosevelti.
Greg went on to describe the morphological features which distinguish A. roosevelti from a A. cuivieri, an ecologically and morphologically similar species from neighbouring Puerto Rico. Roosevelti is a larger, brownish gray rather than green as is seen in cuvieri (although check out these gray cuvieri preveiously mentioned on AA). Roosevelti generally has larger head scales, and a more elongate and deeply grooved head – these differences are confirmed in the ANCOVA analyses below.
So, what chances are there of seeing roosevelti in the wild? Low, probably. No specimens have been collected since 1932, and several researchers, including Greg, have recently scoured both Vieques, St. John and Tortola but with no success. By far the most extensive searches have been conducted by Ava Gaa, who exhaustively searched Culebra (totalling 1500 hours of looking!) as well as short visits to Vieques and St. John all with no success. Tantalising reports of potential candidates turned out to be juvenile green iguanas. Greg concludes by recommending that the long-protected and relatively poorly explored eastern half of Vieques may hold the secret to if any populations remain.
Travis Hagey presented some new results from his ongoing research on the evolution of functional traits in lizards. Travis normally works on geckos, but frequently includes Anolis species in his studies. Last year at Evolution, Travis told us about toepad evolution by comparing gecko toepads to those of anoles and skinks. Along the same vein, this year at JMIH Travis talked about patterns of limb-length across different lizard groups.
Travis started with anoles as an example of morphology being correlated with habitat use. As we all know, anole limb length is associated with structural habitat. Lizards like Anolis occultus (a twig anole) use thin perches and have very short legs. Other species that perch on broader substrates tend to have longer legs. Travis is interested in finding out if this pattern holds for other groups of lizards.
He started by comparing anoles to geckos to see if relative limb length differed between the groups. He accumulated an impressive database of hindlimb lengths from many gecko and 
anole species and when he looked at the relationship between hindlimb length and body size (SVL), he found that for a given body size anoles tended to have longer limbs than equivalently sized geckos. He then added in data for a number of species from Liolaemus, Tropidurus, and Phrynosomatidae. Interestingly, he found that these other groups all clustered with the anoles. This suggests that there are possibly two relationships between limb-length and body size across lizards.
Travis ended by commenting on how this might relate to habitat use. He analyzed hindlimb length by perch diameter for anoles (red line) and geckos (black line). Geckos, it turns out, have a different relationship between perch use and limb length than anoles: geckos with shorter limbs tend to use broader diameter perches! Travis is still working on this research and is looking for data on limb length for many groups. If you have hindlimb length data from lizards you should email Travis to help out!
The gold dust day gecko was introduced to Hawaii in the 1980s. It is ecologically similar to the green anole, which was introduced to Hawaii in the 1950s.
Hawaii has no native herpetofauna, aside from sea turtles. Human-mediated introductions between the 1950s and 1980s have created an interesting new guild of arboreal and diurnal lizards: the green anole (Anoles carolinensis), the gold dust day gecko (Phelsuma laticauda) and the brown anole (A. sagrei ).
Amber Wright next to her poster on Saturday
Phelsuma laticauda belongs to a genus that is endemic to Madagascar with almost 50 species, that are known for their incredible color patterns. Anolis carolinensis and P. laticauda are thought to be ecologically similar and thus potential competitors.
Amber Wright’s research investigates whether and how the three species partition their habitat when they occur in sympatry and how that might affect species abundance. Using field observations and morphological data, she found that the three species overlap in body size and habitat use, which suggests that they are potential competitors for food resources and perch sites.
Enclosure experiment.
Preliminary data show that abundance decreases when ecologically similar species are present.
In a pilot study, Amber used seven 10x10m plots to simulate different community scenarios: only one species, two species and all three species. Anolis carolinensis and A. sagrei seem to be interacting similarly to populations outside of Hawaii: coexistence with reduced densities and increased perch heights of A. carolinensis. When all three species were present, P. laticauda perched higher than usual, presumably to avoid competition with A. carolinensis. Future work will focus on long term effects of species composition on resource partitioning and abundance of each species.
Kevin Aviles-Rodriguez, from the Revell lab at U. Mass. Boston, gave the second urban anole-themed talk of the meeting. Kevin presented his Master’s thesis work that he conducted with the Kolbe lab at U. Rhode Island in a talk titled, “Structural habitat alterations caused by urbanization influence escape behavior of a common lizard.”
Urban habitats are drastically modified and present novel resources and threats for animals that persist and utilize these spaces. Structurally, urban habitats have different types of surfaces that are smoother, broader in diameter, and often more vertically oriented (90° angle). Urban habitats also present abundant and novel food resources in terms of human food and insects attracted to lights and garbage. But with the abundance of food and novel niche space also comes an abundance of novel predators such as cats and dogs kept as pets.
Kevin wanted to know how Anolis cristatellus from San Juan, Puerto Rico and South Miami behaved in urban habitats compared to forest habitats when perceiving a predation threat. Although there are obvious costs of not escaping a predator successfully, there are also costs of fleeing when not necessary in terms of lost feeding opportunities and disrupted social interactions (mating, territory defense). Kevin wanted to know if the urban environment influenced escape behavior decisions. Specifically, he had two objectives: (1) To quantify escape behavior (squirreling, jumping, or sprinting) and how this relates to different types of perches found in urban areas. (2) To measure flight-initiation distance (FID), or how close one can approach an animal before it flees, to see if there are differences between forest lizards and urban lizards.
Kevin found that as perch diameter increases, the probability that a lizard will squirrel around a perch or sprint up the perch increased and the probability of jumping decreased. Interestingly, when he also looked at perch use, he found that the majority of lizards were using perches of thinner diameter where the probability of jumping was highest. Urban lizards also tended to use more isolated perches, which he defined as the number of nearby potential perches within 1 meter. When nearby perch density was lower, lizards tended to jump less – perhaps not all that surprising since they have fewer places to jump to. Kevin also found that escape strategy differed based on the type of perch used. In urban habitats, on trees and on metal posts lizards squirreled more frequently than they did in forest habitats. Interestingly, on cement walls (e.g. buildings) lizards did not jump at all and mainly sprinted to escape. 
Kevin offered a few possible explanations for this trend. For one, building perches tend to be more isolated than trees and so it may simply be that lizards on these substrates have nowhere to jump to. A second possibility is that the lizards have trouble jumping from these perches since they are more vertical than the optimal angle for jumping (39-42°, Toro et al. 2003).
In his final analysis, Kevin found that flight initiation distance (how close you can get to the animal before it flees) was very short for animals perched on urban trees and metal posts. In fact, he commented that on some occasions he was able to get close enough to touch the lizard before it fled! This difference was significantly shorter than for animals perched on trees in the forest and for animals perched on painted concrete walls in the city.
Reptiles are often thought of as solitary and not social animals. However, all of us who study anoles know that Anolis are anything but solitary animals. Spend a few minutes observing an anole and you might see it dewlapping, doing push-ups, tail wagging, and fighting with other males or even other anoles species. James Stroud, a Ph.D. candidate from the Feeley lab @ Florida International University, presented on Saturday about the exploratory results of a new research method he and Robert Heathcote have started to construct social networks of A. sagrei and A. cristatellus in Miami, Florida. A. sagrei and A. cristatellus are similar in morphology and ecology and they wanted to learn how patterns of social interactions between these two species allow them to coexist outside of their native range.
Individual social behavior manifests itself collectively at the population level and interactions between populations (within and between species) might act as a basis for evolutionary processes. James and Robert tagged both male and female anoles in their study to track and recapture the animals in the future for a long term study. They measured the distance between every two anoles observed and inferred the strength of interaction as stronger if the anoles were closer to each other. Both species show a great web of interactions both within and between species. Some individuals are also much more “bold,” interacting with many males and females of either species, while others show fewer social interactions. These preliminary data are exciting since so little is known about Anolis social behavior. James also mentioned that they will be including additional data such as the types of interactions that will add great complexity and insight to this story.
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