Green Anoles in Florida Evolved to Better Compete with Invasive Brown Anoles
October 24, 2014
How do reptiles evolve when another species invades their space? In the case of the Carolina anole (Anolis carolinensis) in Florida, its feet evolved to better climb higher in trees to avoid the invasive brown anole (Anolis sagrei).
Researchers with the University of Texas at Austin studied the evolution of the Carolina anole as it had to deal with the brown anole, a Cuban and Bahaman native that arrived in Florida in the 1950s. The scientists found that in as little as 15 years, the green anole’s feet have evolved to enable them to climb higher in trees and more easily latch onto thinner tree branches.
Credit: Todd Campbell and Adam Algar
Green anoles in Florida evolved to climb higher in an effort to avoid brown anoles.
The scientists say after the green anole made contact with the brown anole more than 50 years ago, the green anole began to perch higher into the trees in which it lived and foraged. After successive generations, the feet evolved to better grip the smoother and thinner branches located at the tops of the trees. Over the course of just 15 years and 20 generations, the lizard’s toe pads became larger and the scales on their feet became more sticky. This enabled the lizard to better avoid the brown anole.
CREDIT: TODD CAMPBELL AND ADAM ALGAR
Over the course of just 15 years and 20 generations, the lizard’s toe pads became larger and the scales on their feet became more sticky.
“We did predict that we'd see a change, but the degree and quickness with which they evolved was surprising," Yoel Stuart, a postdoctoral researcher in the College of Natural Sciences at The University of Texas at Austin and co-author of the study said in a statement released by the university.
The researchers attribute this change to character displacement, a term that evolutionary biologists use to describe when one species competes with a similar species and one or both evolve to take advantage of a new or different ecological niche.
The researchers believe that the green anole adapted as the brown anole competes for the same food, and both lizard species are known to eat the young of the other lizard.
The invasive brown anole first arrived from Cuba and has spread throughout the southeastern United States and has gone as far west as Hawaii and on three islands in Japan.
The study, appears in the October 24 edition of the journal Science.
John B. Virata keeps a ball python, two corn snakes, a king snake, and two leopard geckos. His first snake, a California kingsnake, was purchased at the Pet Place in Westminster, CA for $5. His first pet reptile was a green anole that arrived in a small box via mail order. Follow him on Twitter @johnvirata