The Evolution meetings are now ended, but the fond memories linger on. Such as Yoel Stuart reporting the results of his study of character displacement in Mosquito Lagoon, Florida. Dredge spoil islands were created about 50 years ago when the area was dredged, producing big piles of sand which were subsequently colonized by plants and, eventually, green anoles. Within the last 10 years, many islands were invaded by brown anoles, but some remained sagrei free. Yoel set out to compare the green anoles on islands with and without brown anoles.

First, though, he demonstrated the islands with and without brown anoles didn’t differ consistently in any environmental parameter. Thus, nature has set up a very good experiment.

Yoel found that green anoles perch higher in the presence of brown anoles, presumably a result of interspecific interactions. Moreover, on brown anole islands, green anoles have better developed toepads. A common garden experiment reveals that these differences are  not the result of plasticity. Hence, morphological differences have evolved in a very short time as a result of a habitat shift caused by the presence of another species–an excellent example or rapid evolutionary change and character displacement in action.

Jonathan Losos
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