I’m excited to share an update on my foray into urban ecology and evolution research as an undergraduate! I’ve been working in the Revell Lab at the University of Massachusetts Boston since my freshman year. I’ve reported here before about some of my experiences in the field working on urban anoles. Over the past couple of years I’ve worked with Kristin Winchell (now at Washington University) and Kevin Aviles-Rodriguez (UMass Boston) on my independent research on lizard claw morphology. On the condition of accepting a small undergraduate research grant that went towards defraying the cost of field equipment, I was asked to create and present a digital poster at the annual College of Science and Math Showcase. Here’s a summary of the results to date and my experience presenting at this undergraduate symposium.
The Research
The story I’m telling is about how Anole lizard claws change due to the differences in habitat of the city and the forest. First, we asked if there is a difference between surface roughness of the habitat. Next, we asked if the claw shape varied depending on whether the lizard was caught in the forest or the city.
The idea behind the project is simple: if urban lizards are climbing different types of structures than forest lizards, then we expect there to be differences in traits relevant to climbing. Previous research has shown differences in toepad morphology between forest and urban populations of the lizard Anolis cristatellus. We wondered if and how claw morphology might also differ considering claws are likely to be less effective on the smooth and hard surfaces common to urban environments such as metal and painted concrete.
I started this research with Kristin in the Bahamas in 2018, catching and imaging hundreds of claws from Anolis sagrei from a forest and urban population in Nassau. I then went back to Puerto Rico with Kevin where I did the same for Anolis cristatellus in an urban and forest population from Arecibo. For both, we also took macro photos of the surfaces the lizards were perched on to get an idea of how the roughness of surfaces differed between habitat types.
Over the past few months, I traced each of the several hundred claw images to apply semi-landmarks in TPSdig, then used a geometric morphometric approach to quantify how claw shape differs between urban and forest populations (similar to the approach used by Yuan et al. 2019). I also calculated surface roughness values from the macro images using ImageJ.
So far we have analyzed the data for A. cristatellus only, but we have already found some interesting results! To start, we found that the forest had significantly rougher surfaces than the city. This makes sense because surfaces in the forest are rough such as trees, bark, and woody vines, but surfaces in the city are smooth, like glass, metal, and concrete. With regard to claw shape, we found that the rear claw was significantly different in shape between the two habitats – urban claws tend to be shorter in length and taller at the base.
The Poster Presentation
Once I collected all the data, which took over ten weeks (analyzing one hundred surface images and four hundred Anolis claw images is no joke), creating this poster was an insanely fun task. I enjoyed compiling the photos, wrangling the data into graphs, and telling a fun story about science.
However, the best part about poster sessions is actually presenting! It was super nerve-wracking because although I do participate in public outreach and other forms of scientific communication, I was nervous to talk about my own research. That being said, it was fun to get the word out about urban research. I can safely say that all of the other posters were mainly about proteins and pathways in drosophila or mice and none of the posters were about adaptation to urbanization.
Because of the relative scarcity of urban ecology topics, I got a lot of interesting questions about this emerging field. Many visitors were surprised to learn that people actually want to study animals that live in the city and why they are successful. Visitors were also drawn by the pictures of cool lizards and wanted to know more about herpetology, one of my life’s passions.
All in all, the presentation was a roaring success. It was a great experience to practice science communication, talk about my research interests, and get the word out about urban ecology and evolution! And of course I was thankful to my lab members who stopped by for some photo ops!
What’s next? In addition to incorporating the A. sagrei claws into the analysis, we now also have claw images from an urban and forest population of two species from Kingston, Jamaica (Anolis grahami and Anolis lineatopus) and will soon have images for Anolis cybotes from Santo Domingo in the Dominican Republic! Stay tuned to hear more about this research as I work my way through these data!
- Recap: The Finer Points of Urban Adaptation - January 29, 2021
- Video Recommendation: The City Animal Tier List! - March 10, 2020
- Urban Observation of the Week: A Catalogue of Urban Animals in Gamboa, Panama - September 4, 2019
This is a fascinating and much needed research agenda. Thanks for sharing it so that even a layperson can understand it!