1. Tallgrass Prairie Center 2412 West 27th Street Cedar Falls IA 50614‐0294 U.S.A.
2. Department of Biology University of Northern Iowa Cedar Falls IA 50614‐0421 U.S.A.
3. Division of Biology Kansas State University Manhattan KS 66506 U.S.A.
4. Department of Biology University of New Brunswick Fredericton NB E3B 5A3 Canada