1. Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
2. Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
3. Department of Life Sciences, Scarborough Campus, University of Toronto, Scarborough, Ontario M1C 1A4, Canada
4. Department of Forest Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
5. Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada