Jordan Bush giving her talk on the interaction between green and brown anoles at SICB 2020

Green and brown anole interacting within Jordan’s enclosures.

As brown anoles (Anolis sagrei) become more and more abundant, many people (trained and citizen scientists alike) are intrigued with exactly how the native green anole (A. carolinensis) will respond. Newspaper articles still report on these interspecific interactions, and some recent research has shown the brown anoles can be quite mean to the native green. Thankfully, it seems that the green anole may simply be moving higher into the canopy and aren’t being merely driven to extinction by the invading brown. However, we do not yet understand the nuances of how green anoles respond when brown anoles first arrive to a new location, and that’s where Jordan Bush, a sixth year PhD student in Dan Simberloff’s lab at the University of Tennessee, Knoxville, comes in.

To understand how green anoles immediately react to the novel presence of brown anoles, Jordan built 5 x 5 x 5m enclosures in which she placed 6 female and 6 male green anoles. These animals then set up territories and became acclimated to their new living space. Jordan quantified baseline behavior and territory sizes (in 3D!!!) for each individual in an enclosure.

Example 3D territories

After 10 days, Jordan introduced brown anoles in these enclosures, either two females and two males or four females and four males to investigate the effects of density, and quantified behavioral and territorial changes in the green anole. Being the careful researcher that she is, she also introduced the same number of green anoles to other enclosures so that she could show that any changes in behavior were not simply due to more animals being present. After 10 days of interacting with the brown anole, Jordan found no change in activity level, home range volume, or perch height, suggesting that, at least within an acute time frame, the green anole can handle its own against the brown anole.