Male Carolina anole (left); male brown anole (right)WIKIMEDIA, R. COLIN BLENIS (L), HANS HILLEWAERT (R)For most of its existence, the Carolina anole (Anolis carolinensis) was the only lizard in the southwestern U.S. It could perch where it wanted, eat what it liked. But in the 1970s, aided by human pet trade, the brown anole (Anolis sagrei)—native to Cuba and the Bahamas—came marching in. In experiments on islands off the coast of Florida, scientists studying the effects of the species mixing witnessed evolution in action: the Carolina anole started perching higher up in trees, and its toe pads changed to enable better grip—all in a matter of 15 years, or about 20 lizard generations.
In a paper published in Science today (October 23), Yoel Stuart of the University of Texas at Austin, Todd Campbell from the University of Tampa, Florida, and their colleagues discuss what happened when the two species converged upon the same habitats.
“It’s a cool paper and I am excited by it,” said Daniel Simberloff, a professor of ecology at the University of Tennessee, Knoxville, who was not involved in the study. “It confirms a couple of theories that I’ve been interested in: rapid evolution and character displacement.”
When closely related species compete, they may evolve to become different from one another. Called “character displacement,” this process can result in evolutionary changes that reduce further interactions between the species. A. carolinensis and A. sagrei have similar ...
