1. Department of Botany, University of Toronto, Toronto, Ontario, M5S 3B2, Canada
2. Smithsonian Tropical Research Institute, PO Box 2027, Balboa, Republic of Panama
3. Section of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA
4. Department of Zoology, University of Otago, PO Box 56, Dunedin, New Zealand