Where do you work and what do you do?  

I live and work in Toronto, Canada where I’m an Assistant Professor of Ecology and Evolutionary Biology at the University of Toronto. At the university I teach classes in macroevolution and herpetology, and I lead a research lab focused on the ecology and evolution of Anolis lizards. The central aim of our work is to understand how historical and ecological factors interact to produce large-scale patterns of biodiversity. My group’s research involves a combination of laboratory work, computer work, and fieldwork, and one of the perks of my job is that it frequently takes me to the many diverse and interesting places where anoles live in the wild. 

What aspects of anole biology do you study, and what have you learned? 

One of the central aims of my research has been to investigate how ecological factors – such as competition between species – shape evolution over very long time periods (millions of years – i.e., over macroevolutionary timescales). To answer these questions, I first reconstruct the evolutionary relationships of anoles by analyzing their DNA, resulting in a phylogeny, or evolutionary tree. I then use this phylogeny to examine the history of past evolutionary changes for the group, and to ask questions about the causes of such changes. 

Applying such techniques, I’ve learned that the rate of trait evolution can be higher when anoles speciate and adapt in the absence of ecological competitors, slowing down as competing species eventually accumulate. Using similar approaches, I found evidence that while the ecological niches of anoles can evolve quite rapidly when opportunity knocks, they can also remain stable for many millions of years following an initial burst of diversification and adaptive evolution. 

Recently, my lab has also begun to study how anoles are responding to global change wrought by humans (e.g., due to the conversion of forest habitat to pasture or agriculture). One interesting recent discovery is that anole communities respond differently to deforestation in lowland versus highland environments on Hispaniola. In the lowlands, deforestation results in reduced abundances of anoles, but causes little change in what species occur at a site. In the highlands, however, deforestation has little effect on anoles abundances, but results in a complete turnover in the species that occupy the site. Specifically, the forest-specialist highland anole species disappear with the forests they require, and are replaced by heat-loving opportunists from the lowlands, which thrive in the new, and relatively warm, pasture habitats. These results suggest that the response of anole communities to deforestation depends on climate and altitude, and that accounting for these factors will be key to predicting future biodiversity change. 

How and why did you start studying anoles? 

I love working on anoles, but that was not always the case! When I started grad school, I wasn’t keen on working with anoles precisely because they were such a well-studied group. My (somewhat naïve) impression was that all the interesting stuff had already been figured out, and that my efforts would be better spent working on a less well-known group (e.g., African chameleons, or Asian skinks). Indeed I began my grad studies by collecting preliminary data on such groups, with somewhat mixed success. At the same time, I began working on anoles “on the side,” participating in a project investigating patterns of evolution in mainland versus island radiations of anoles. Slowly I began investing more in this work, and of course encountered new, unanswered questions that led to yet more work. Before I knew it, I was working on anoles a LOT, and to my surprise I (1) was really enjoying it, and (2) was making real progress answering the sorts of questions that had always interested me. It was an organic process, but before long these ideas coalesced into a PhD thesis project on rates and patterns of macroevolution in anoles. What I learned along the way is that there are always more scientific questions to ask – contrary to my initial intuition, all that previous research on anoles in fact made it possible to ask deeper and more exciting questions by studying the group. 

What do you love most about studying anoles? 

The pragmatic part of my answer is that I love their replication. Anoles are an unusually excellent study group because when they do something (e.g., evolve to live in shallow caves, or to live in grass tussocks, or to use freshwater streams, or even to have a fleshy horn mounted on their snout), they typically do it multiple times. This replication allows us to make comparisons that can help us tease out the most important mechanisms behind macroevolutionary change (e.g., via statistical analysis). Anoles have diversified throughout the New World tropics both in continental settings and on the islands of the West Indies, and this means that they’ve evolved for millions of years in similar (and different) ecological settings many times independently. Anoles are effectively a “natural experiment” for macroevolution, and they provide us a rare opportunity to investigate how repeatable macroevolution can be, and to identify the factors that influence it the most. 

The other part of my answer is that anoles always have something new to teach us. Even for species I feel like I know very well, I’m constantly learning something unexpected about them – both during my own fieldwork, and also from creative published work by others. The pace of discovery is rapid in anoles, and that makes working on the group a lot of fun. 

What is your favorite anole species? 

This is an impossible question. I’ve listed a provisional “top 10” below, from the top of my head. Any of these could change at any point, especially if I get the chance to see Anolis megalopithecus or any member of the Chamaeleolis clade in the wild!  

A. fowleri – A beautiful, mysterious, and rare Hispaniolan montane anole. Finding one of these for the first time about a decade ago was a personal triumph. 

A. landestoyi – I had wanted to describe a new species since I was a kid. I had the opportunity to do that with this species, which my good friend Miguel Landestoy discovered in the Bahoruco mountains in the western Dominican Republic. What makes this anole particularly interesting is that, despite being discovered in the 21st century on a relatively well-studied Caribbean island, it is totally unlike any other Hispaniolan anole. Instead, it’s very similar to Cuban anoles in the Chamaeleolis clade, and this similarity may represent yet another example of among-island convergence for Greater Antillean anoles. 

A. reconditus – Another poorly-known montane endemic, this time from Jamaica. They’re quite colorful, and males are big! I was able to observe several deep in elfin montane forest in the Blue Mountains in 2018, and I was impressed by how bold and inquisitive they were (one traversed several tree trunks to dewlap at me from close range). 

A. purpuronectes – A recently described species from Mexico. This is a strikingly beautiful semi-aquatic anole from Oaxaca and Veracruz. I was along on the trip led by Levi Gray and Steve Poe where this species was first recognized as new.  

A. distichus – Most of my favorite anoles are either rare or are unique for some reason. But I also have come to appreciate the more common anoles, and distichus is among the commonest you’ll ever find. In recent fieldwork with my lab I’ve come to appreciate the resilience of this species – I’ve always thought of it as thriving in forest edges and other disturbed habitats, but unlike many such species, it’s even more abundant in the forest interior. 

A. gorgonae – An entirely cobalt blue anole (dorsally, anyway) found only on the Colombian island of Gorgona. Enough said. 

A. proboscis – A twig-ecomorph-like Ecuadorian anole with a scaly sword sticking out of its face! 

A. alvarezdeltoroi – This is what you get when you try to make a spider from an anole. It’s a cave-dweller from Mexico and it has an absolutely stunning red dewlap. 

A. eugenegrahami – An all-black semi-aquatic anole found only near the town of Plaisance in northern Haiti. Perhaps the most poorly studied of the semi-aquatic anoles, and certainly the most endangered. 

A. sheplani – A tiny Hispaniolan twig anole with extremely short limbs. I love twig anoles. 

Where can people learn more about you and follow you online?

www.mahlerlab.com 

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