At the JMIH in New Orleans this past July, the 100th anniversary celebration of the ASIH was held at the Rock ‘n’ Bowl, where music, food, drink, dancing, and bowling were enjoyed by all. But for those who were alert on their way in, there was an added bonus: anoles! Or, at least, one anole, spotted by Quynh Quach and corralled by Kristin Winchell.
As other attendees file in, Quynh and Kristin spot their quarry in the bushes.
Taking a picture of the crowd filing in, I serendipitously caught our two intrepid anoleers about to make the catch in the bushes to the right of the entrance. Kristin made the grab, and displayed her catch.
Kristin displays the catch.
It was, of course, Anolis sagrei, the invasive Cuban species which has been spreading through the southeastern US for more than 80 years now. He was a nice-sized adult male, typical of the nominate form that occurs through most of the species’ US range. The edificarian habitat– in bushes at the edge of a parking lot next to a building– is also typical of where invasive sagrei can be found.
Adult male Anolis sagrei, New Orleans, Louisiana, 10 July 2016.
An appreciative crowd gathered.
Eager anolologists immortalize the NOLA anole in pixels.
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.
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.
Bright and early this morning, Christopher Peterson kicked off the anole talks of the day on the topic “Intraspecific color and habitat use variation in Anolis conspersus.” Christopher noted that on Grand Cayman there appear to be three color morphs for A. conspersus: brown, blue, and green and asked if color morph was correlated with habitat use. Christopher captured 309 lizards across the island, photographed them for color analysis, and took a large number of habitat measurements plus basic morphology of the lizards (mass, SVL). When analyzing the color data, however, he noticed that the picture was not so clear: many of the lizards had both blue and green coloration. Since these were not discrete groups, instead he analyzed body pattern, which appeared to be more discrete and showed the same geographical variation. In general, lizards on the East of the island were brown and spotted while the lizards on the West of the island were green/blue with vermiculated pattern.
Using a complex logistic regression, Christopher analyzed the discretized character state with his habitat and morphological measurements. Disappointingly, he found no associations between morphology or habitat use with body patterns. He concluded that the variation in pattern and coloration is probably best explained by geographic location alone and that future genetic analyses may help clear up if this is a geographical cline with isolation by distance.
