1. Department of Biology, Pennsylvania State University, Shenango Campus, Sharon, Pennsylvania 16146, U.S.A.
2. Department of Biology, Whittier College, Whittier, California 90608, U.S.A.
3. University of Oklahoma, Sam Noble Oklahoma Museum of Natural History, Norman, Oklahoma 73072, U.S.A.
4. Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas 66045, U.S.A.