a1 Department of Ecology and Evolutionary Biology, Dartmouth College, 54 College St., Hanover, NH 03755, USA
a2 Department of Biology, Truman State University, 100 E. Normal St., Kirksville, MO 63501, USA
a3 Department of Biology, Dickinson College, 105 Dana Hall, Carlisle, PA 17013, USA
a4 U.S. Geological Survey, Fort Collins Science Center, 2150 Centre Ave, Bldg C, Fort Collins, CO 80526, USA
a5 Department of Biology, University of Texas at Arlington, 501 S. Nedderman Drive, Arlington, TX 76010, USA
Studies of recently isolated populations are useful because observed differences can often be attributed to current environmental variation. Two populations of the lizard Anolis lemurinus have been isolated on the islands of Cayo Menor and Cayo Mayor in the Cayos Cochinos Archipelago of Honduras for less than 15 000 y. We measured 12 morphometric and 10 habitat-use variables on 220 lizards across these islands in 2 y, 2008 and 2009. The goals of our study were (1) to explore patterns of sexual dimorphism, and (2) to test the hypothesis that differences in environment among islands may have driven divergence in morphology and habitat use despite genetic homogeneity among populations. Although we found no differences among sexes in habitat use, males had narrower pelvic girdles and longer toe pads on both islands. Between islands, males differed in morphology, but neither males nor females differed in habitat use. Our data suggest that either recent selection has operated differentially on males despite low genetic differentiation, or that they display phenotypic plasticity in response to environmental variation. We suggest that patterns may be driven by variation in intrapopulation density or differences in predator diversity among islands.
(Accepted December 12 2011)