1. Department of Integrative Biology, Oregon State University, Corvallis, OR 97331, USA
2. Department of Biology, University of North Carolina at Chapel Hill, NC 27599, USA
3. Concord Field Station, Department of Organismic and Evolutionary Biology, Harvard University, Old Causeway Road, Bedford, MA 01730, USA
4. Field Research Station at Fort Missoula, Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
5. Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK