1. Department of Biological Sciences The University of Alabama Tuscaloosa Alabama 35487 USA
2. School of Biology and Ecology University of Maine Orono Maine 04469 USA
3. Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor Michigan 48109 USA
4. Departamento de Genética, Evolução e Bioagentes Universidade Estadual de Campinas Campinas SP 13082‐862 Brazil