1. Faculty of Symbiotic and Environmental Sciences, Prefectural University ofKumamoto, Kumamoto 862‐8502, Japan;
2. Department of Plant Ecology, Utrecht University, P.O. Box 80084,3508 TB Utrecht, The Netherlands
3. Graduate School of Science, Osaka City University, Osaka 558‐8585, Japan
4. Faculty of Agriculture, Utsunomiya University, Utsunomiya 321‐8505, Japan;
5. Graduate School of Agriculture, Kyoto University, Kyoto 606‐8542, Japan;
6. Forest Department, 93660 Kuching, Sarawak, Malaysia
7. Department of Organismal and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA