An invading lizard species from Cuba might have caused local Florida species to evolve significantly over only 15 years.
Once the invasive species hit the scene, the native lizards moved to higher perches, causing their feet to evolve through the generations to grip thinner, smoother branches, the University of Texas at Austin reported. The lizards' toe pads became larger and developed more sticky scales.
"We did predict that we'd see a change, but the degree and quickness with which they evolved was surprising," said Yoel Stuart, a postdoctoral researcher in the Department of Integrative Biology at The University of Texas at Austin and lead author of the study appearing in the Oct. 24 edition of the journal Science.
The rapid evolution is comparable to a scenario in which the average height of humans increased by seven inches over only 20 generations.
The native lizards studied, known as Carolina anoles or green anoles, are developing at such a rapid pace to compete with the invasive brown anole, which was first spotted in Florida in the 1950s.
The finding is one of very few examples of a phenomenon known as "character displacement," in which competing species evolve to fit different ecological niches; another example of this are Darwin's Galapagos finches, which evolved shaped beaks to take advantage of different food sources. The same developments are believed to be occurring in the green and brown anoles.
"So it may be that if you're a hatchling, you need to move up into the trees quickly or you'll get eaten," Stuart said. "Maybe if you have bigger toe pads, you'll do that better than if you don't."
Stuart's co-authors are Todd Campbell at the University of Tampa; Paul Hohenlohe of the University of Idaho; Robert Reynolds of the University of Massachusetts, Boston; Liam Revell at the University of Massachusetts, Boston; and Jonathan Losos at Harvard University.
