1. Department of Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, CA 93106-9610, USA
2. Department of Zoology, University of British Columbia, Vancouver, BC,Canada V6T 1Z4
3. Biology and Wildlife Department, University of Alaska, Fairbanks, AK 99775, USA
4. Smithsonian Tropical Research Institute, Balboa, Republic of Panama