Evolution 2015 is officially over and we have all sadly left beautiful Guarujá, Brazil. There were a lot of great talks and posters and a great representation of South American students and researchers. For coverage on the conference as a whole, check out #evol2015 on twitter! The herps were few and far between (I only saw 2 in my 16 days in Brazil!) but the posters and talks on herps were numerous. Unfortunately, anoles were poorly represented at Evolution this year with only three anole talks and a couple of others that briefly highlighted anoles. If you weren’t able to make it to Brazil, I’ve got the recap for you here.
Starting off in one of the first sessions was a talk by Travis Hagey titled “Independent Origins, Tempo, and Mode of Adhesive Performance Evolution Across Padded Lizards.” Although his talk was mostly about geckos, he did shine the spotlight on anoles for a few minutes. He focused on the phylogenetic pattern of toepad adhesion in pad-bearing lizards: geckos, skinks, and anoles. Specifically he looked at how clinging ability (measured as angular detachment – check out one of his videos showing this) varied within and among clades. Unsurprisingly, he found that anoles don’t cling nearly as well as geckos. He also demonstrated that gecko toepad diversification best followed a Brownian motion model with weak OU and anole toepad diversification was best fit by a strong Ornstein–Uhlenbeck process. In other words, gecko toepads diversified slowly over a very long period while anoles were quickly drawn towards an optimum over a short time-period. Travis concluded that these patterns explain why there is a large amount of diversity in gecko toepads but not in anole toepads.
Next up was Joel McGlothlin, who also gave a non-anole talk titled “Multiple origins of tetrodotoxin‐resistant sodium channels in squamates.” Joel mostly talked about garter snakes, but did manage to squeeze in anoles a couple of times as he told us about his research on the evolutionary origin of tetrodotoxin resistance. His exciting results will be coming to print soon, so keep an eye out for the full story.
Fernanda de Pinho Werneck gave a lighting talk titled “Cryptic lineages and diversification of an endemic Anole lizard (Squamata, Dactyloidae) of the Cerrado hotspot” that I am sad to have missed. If anyone did catch it, please let us know in the comments.
My talk, “Urban Evolution: Natural selection and genetic basis of phenotypic shifts in urban Anolis cristatellus” was bright and early on Sunday morning. I talked about my ongoing research in Puerto Rico on adaptation to urbanization. I first recapped some key results I discussed last year: that A. cristatellus in urban areas have longer limbs and more lamellae. When I first presented this research at JMIH in 2013, a number of people commented that the morphological shifts I had observed were likely the result of phenotypic plasticity. In answer to this, I brought back male and female lizards from an urban and natural population in Mayagüez, bred them in our animal care facility at U. Mass. Boston, and reared the offspring in identical conditions to one year of age. Two years later and I can now tell you that the differences in lamellae number and limb length do appear to have a genetic basis. I also talked briefly about the mark-recapture selection experiments I have been conducting in Arecibo. Out of three populations sampled to date, we have observed survival rates of approximately 20% over four months. More detailed results from both of these projects will be coming soon!
Lastly, Matthew McElroy also gave a talk on Anolis cristatellus, “Gene flow and the “Bogert effect”: genes move up mountains in the Puerto Rican Crested Anole.” Matt’s talk focused on two questions: Does phylogeographic structure correlate with thermal gradients in Puerto Rico? and How does gene flow move with respect to thermal gradients? When he looked at the phylogeography, he found that there were three populations of A. cristatellus in Puerto Rico and that these correspond to distinct ecological regions in the northeast, northwest, and south (see my photos below of anoles in these unique habitats). Using niche modeling, he determined that there is little niche overlap between the three regions and that the main drivers of environmental differences are related to precipitation and seasonality. Perhaps the coolest part of this story was that when he analyzed migration he found gene flow from the south to both of the north regions, but not in the other direction. These results suggest that locally adapted thermal phenotypes are selected against when lizards cross into the other ecological regions, particularly cold adapted phenotypes attempting to move southward.