Anole Annals

The IUCN (International Union for the Conservation of Nature) has a detailed protocol for assessing the conservation status of species. A report on the world’s reptiles was published in 2013. Now, a paper by Johnson and colleagues in Amphibian & Reptile Conservation complains that the IUCN’s methods are not efficient and proposes a simpler, faster method.

Their abstract explains:

“Mesoamerica, the area composed of Mexico and Central America, is the third largest of the world’s biodiversity hotspots. The Central American herpetofauna currently consists of 493 species of amphibians and 559 species of crocodylians, squamates, and turtles. In this paper, we use a revised EVS measure to reexamine the conservation status of the native herpetofauna of this region, utilize the General Lineage Concept of Species to recognize species-level taxa, and employ phylogenetic concepts to determine evolutionary relationships among the taxa. Since the publication of Conservation of Mesoamerican Amphibians and Reptiles , in 2010, 92 species of amphibians and squamates have been described, resurrected, or elevated from subspecies to species level, and one species of anuran has been synonymized. The herpetofaunal diversity of Central America is comparable to that of Mexico, an especially significant finding because the land area of Mexico is 3.75 times larger. The number of amphibian species is 1.3 times greater in Central America, whereas the number of species of turtles, crocodylians, and squamates is 1.5 times greater in Mexico. Endemicity also is significant in Central America (65.6% among amphibians, 46.5% among turtles, crocodylians, and squamates), with a combined average of 55.6%. We regard the IUCN system as expensive, time-consuming, tending to fall behind systematic advances, and over-dependent on the Data Deficient and Least Concern categories. Conversely, the EVS measure is economical, can be applied when species are described, is predictive, simple to calculate, and does not “penalize” poorly known species. Our EVS analysis of amphibians demonstrates that on average salamanders are more susceptible to environmental deterioration, followed by caecilians, and anurans. Among the remainder of the herpetofauna, crocodylians are the most susceptible and snakes the least, with turtles and lizards in between. We compared the EVS results for the Central American herpetofauna with those reported for Mexico; the results from those regions show an increase in numbers and percentages from low through medium to high. Arguably, attempting to conserve biodiversity is one of the most important and intransigent issues facing humanity, a situation partially due to humanity’s lack of appreciation for its most serious concerns, and brought about by its anthropocentric focus.”

But what about anoles, you are no doubt thinking? In Johnson et al.’s EVS classification, all Central American anole species are rated as medium or high vulnerabilty, except the following species that are rated as low vulnerability: Anolis biporcatus, A. crassulus, A. laeviventris, A. lemurinus, A. petersi, A. sericeus, A. tropidonotus, and A. unilobatus.

You gotta’ love the cover of the June issue of Mesoamerican Herpetology. The photo is of Anolis insignis photographed at Sector Pocosol del Bosque Eterno de los Niños, Provincia de Alajuela, Costa Rica by Victor Acosta Chaves.

The issue contains new distribution records in Mexico for A. carolinensis, A. sagrei and A. sericeus.

Photo by Patricia Sander from New Orleans, LA.

We’ve had reports of red-headed and orange-headed A. sagrei previously, but here are some new records. Bob Thomas, Director of the Center for Environmental Communication at Loyola University in New Orleans, sent along photos of red heads from both New Orleans (above) and Mississippi (below). If you click on the links to the previous posts, you’ll see that these have been reported far and wide, but we have no idea whether there is any adaptive significance to this stylish look.

Photo by Brad Glorioso from Hancock Co., MS

Photo by D. Burgess

AA’s man in northern Florida, Joe Burgess, went on a special trip to the Riverside section of Jacksonville to nab these pix for our viewing edification. Thanks, Joe!

Photo by D. Burgess

Note added August 26, 2015: Karen Cusick did some sleuthing and discovered that the mural is located on Lomax Street and was painted by Shaun Thurston, who has done many other murals in the city, but none with an anoline theme.

The caption to this photo, which appeared in the Florida Times-Union: the brown anole has overrun Florida. Sometimes called Cuban anoles, they have become the most abundant vertebrate on Florida land.

The Florida Times-Union from Jacksonville published an article today on Florida invasives that arrived from Cuba. Pasted below is what they have to say about our favorite, the brown or festive anole, Anolis sagrei. You’ll have to go to the paper’s website to read about the Cuban brown (or festive?) snail and the Cuban treefrog:

This little lizard has an aggressive streak.

Related: Warming Cuba relations spurs invasive species debate

Swiftly, quietly, the brown anole has overrun Florida. Sometimes called the Cuban anoles, they have become the most abundant vertebrate on Florida land, with recorded populations exceeding 10,000 per hectare.

But really, this is a tale of two lizards. When the brown anole first started to colonize the Florida mainland in the 1940s, it came across another lizard, small and slender just like itself.

The bright green Carolina anole had been the only anole lizard native to Florida, and it had prospered across the Southeast United States. But, suddenly, it found itself in a turf battle with the invading brown anole.

They were both color-changing lizards, between 5 to 8 inches in length, competing for the same territory and the same food. But the brown anole had the upper hand. Back in Cuba, it shared an island with over 60 other anole lizards. It had to bulk up to face its rivals.

“In some sense, it’s better evolved, better adapted to competing with other anoles, so when it gets to Florida, it’s more aggressive and a little bit heavier,” said Yoel Stuart, a post-doctoral researcher in integrative biology at the University of Texas at Austin.

He told the Times-Union that he has heard many native-born Floridians lament the disappearance of the green Carolina anole in recent years, as the brown ones took over.

But all is not lost for the Carolina anole.

Stuart led a study of Carolina and Cuban anoles, and he found that the little green lizards were evolving rapidly to face down the invading force.

For their study, Stuart and his colleagues “battled weather and salt water and malfunctioning motors and leaky boats,” to reach isolated islands on Florida’s Atlantic coast.

They arrived armed with what Stuart describes as “a little extendable fishing pole with a little lasso at the end of it.” And when they spotted a lizard, they tried to slip the lasso around its neck, to collect measurements.

The Cuban anoles had, as expected, settled all but five of the 30 islands they visited. But how quickly the Carolina anoles were reacting surprised the researchers. They had fled to the canopy where, in the course of just 15 years, they had sprouted vastly bigger feet with stickier scales.

“If human height were evolving as fast as these lizards’ toes, the height of an average American man would increase from about 5-foot-9 inches today to about 6-foot-4 inches within 20 generations,” Stuart said in a news release. That would make the average American the same size as a NBA shooting guard.

That rapid evolution will likely allow the Carolina anole to coexist with the brown anole.

“It’s not going to go anywhere,” Stuart said. “It’s just going to be a little less abundant, a little bit higher up in the trees.”

But Stuart sees the brown anole’s rampant success as a warning, especially as other exotic lizards try to make Florida their home. He points out that South Florida is under siege by tegu and monitor lizards.

“People should realize if they buy a pet and can’t keep it, they shouldn’t just release it,” he said. “You never know which one is going to take off and start breeding in the wild.”

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In a recent paper in Life: the Excitement of Biology, Neftalí Ríos-López and colleagues report an observation of a male Anolis gundlachi catching an eating a coqui frog.  Here’s the short story–read the paper for more details: “…we observed a male Anolis gundlachi (Yellow-Chinned Anole: SVL 57.1 mm; tail length 88.1 mm) that sprinted down a trunk (8.7 cm diameter at breast height) of a Sierra Palm (Arecales: Araceae: Prestoea acuminata var. montana [Graham] An. Hend. and Galeano, 1996), dived into the leaf litter, and caught an adult E. wightmanae by his head (SVL 22.4 mm; this individual was not calling).”

By coincidence, shortly before seeing this article, we were alerted that Carmen Reyes had posted this photo on Facebook. Here’s her report: “We just went to visit a friend and I saw this lizard with something too big for him in his mouth. I took a closer look but not too close so I can have a better look… and voilà, it was a coqui…First we thought that he had a cockroach. I took the picture and as I got closer, he moved and started climbing the wall, but the coqui fell from his mouth… so I hope that the coqui is alive.

Photo by Carmen Reyes

Lausanne, Switzerland was host to this year’s European Society for Evolutionary Biology (ESEB) Conference. Despite the great distance between Europe and the native habitat of anoles, they did feature in several presentations: there was one anole talk and three posters, and many references to Anolis research during other presentations.

The single anole talk presented by Katie Duryea, currently at Lund University was about sexually antagonistic selection on body size in Anolis sagrei. The study, conducted on wild lizards across three years, investigated the relationship between fitness (estimated from the number of offspring surviving in the following year) and body size in males and females separately. The study demonstrated a strong positive relationship between body size and fitness in males across all three years. In contrast, selection on female body size varied across the three years. Her study nicely demonstrated sexually antagonistic selection acting on body size in a wild population.

The three posters spanned a wide range of research questions: invasion biology, transcriptome analysis and local adaptation. The first poster in the program was by Wataru Anzai from the University of Tokyo. He studied morphological and behavioural differences between introduced populations of Anolis carolinensis on two Japanese Islands. Sexual dimorphism in body size, head shape and limb musculature differed between the Islands. In behavioural experiments, he demonstrated that these traits were important during male-male competition.

The second poster was from another Japanese researcher, Hiroshi Akashi from Tohoku University. In this work Hiroshi and colleagues sequenced the transcriptomes of three anole species (A. sagrei, A. homolechis and A. allogus) under different thermal environments (5 days 26⁰C and 33⁰C). The study found that the expression of many genes varied with temperature, but that only one of these differentially expressed genes was shared across species.

The final poster was that of Michael Logan from Stellenbosch University. He presented work on thermal adaptation and gene flow in A. sagrei occupying Islands. He found that lizard thermal performance closely matched their local thermal environment, indicative of local adaptation. Interestingly, gene flow was greatest between islands with similar thermal environments, suggesting that effective migration may be higher between these islands.

Overall ESEB15 showcased a tremendous amount of exciting Evolutionary research and if you want to know more here is a link to ESEB15 webpage and abstract booklet, or you can check out some tweets using #eseb15. Some other exciting news from the conference was that in 2018 Montpellier, France will be host to a joint meeting between ESEB and Society for the Study of Evolution (SSE). The joint meeting will be a great opportunity to exchange ideas and establish networks across the pond. The conference structure will be a hybrid between the Evolution and ESEB formats, which differ quite a bit. At ESEB the program is divided into Symposia that are proposed by participants well in advance. Each symposium has 2-3 invited 30-minute talks and ~ 4-6 15-minute selected talks. The size of the meeting is usually capped at about 1500 and this year they had 8 concurrent sessions. If you do the maths (or math as you say in USA), you will notice that most participants do not get accepted for talks (~1/3) and the bulk of presentations are posters. The 2018 meeting will have approximately 2500 people, ~1000 talks and 14 parallel sessions. It would be great to have a strong anole contingent at the joint meeting in 2018, so keep a look out for the call for symposia and the call for abstracts. Hope to see you all there.

Size dimorphism among Anolis habitat specialists from Butler et al. 2003

In recent years the Anolis community has shown greater interest in understanding the developmental bases of anole diversity. As these data accumulate, we can start to synthetically understand the ecological (ultimate) and developmental (proximate) factors that regulated different aspects of anatomical diversification in anoles. Differences between males and females (i.e., sexual dimorphism) is one area that has received a considerable amount of attention among anole biologists interested in obtaining this integrative understanding of anatomical diversity. Over the last decade a number of papers have been published examining the evolutionary patterns of anatomical differences, ecological correlations, and the developmental/physiological processes underlying dimorphism in anoles.

Variation in body proportion (i.e., shape dimorphism) among Anolis habitat specialists from Butler et al 2003.

Compared to other anoles, crown-giant anoles have relatively low levels of size dimorphism, but vary greatly in body proportion. Males and females tend to vary in relative limb length, head proportions, and in the dimensions of their adhesive toe pads. In a recently published paper Vanhooydonck et al. examine the timing of divergence between male and female A. baracoae. They raised 23 individuals (9 males, 14 females) for 3.5 years, repeatedly measuring three anatomical traits and bite force 11 times over this time period. The authors found that bite force and dewlap size exhibit significant differences in growth between the sexes. Their analysis further suggests that these traits diverge at different times during ontogeny – bite force diverges during juvenile growth while dewlap size does not diverge until sexual maturity – illustrating the independent regulation of dimorphic traits during development. Head length and hindlimb length did not appear to have sexual differences, although it would be interesting to also perform a formal analysis of adult size and shape dimorphism on A. baracoae to see if this species has similar dimorphic trends compared to other crown-giant anoles.

The developmental bases of size dimorphism in A. sagrei from Cox et al. 2009

These results are consistent with other studies that show a mosaic pattern of male and female phenotypic divergence. Using a longitudinal study of male and female A. sagrei, Cox et al. 2009 showed us that body size dimorphism in this species begins early in juvenile life, only three weeks after hatching. Sanger et al. showed that dimorphism in facial length can emerge through two distinct developmental strategies, one early in ontogeny and one at the time of sexual maturity that appears to be clade-specific. Additional research on that compares across traits and among species will further elucidate the number of ways that dimorphism can arise in anoles. Further work that overlays an ecological perspective onto these patterns will also allow a more thorough understanding of whether natural or sexual selection is the primary driver of these differences in timing. As this future work progresses new insights into the evolutionary processes of anatomical diversification are sure to follow.