1. Department of Ecology and Evolutionary Biology; Yale University; New Haven Connecticut 06520
2. Current Address: Baker Institute for Animal Health, College of Veterinary Medicine; Cornell University; Ithaca New York 14583
3. Department of Biomedical Engineering; Yale University; New Haven Connecticut 06520
4. Yale Institute for Biospheric Studies; Yale University; New Haven Connecticut 06511
5. Department of Molecular, Cellular, and Developmental Biology; Yale University; New Haven Connecticut 06511