1. Biodiversity division, National Institute for Environmental Studies, Tsukuba, Ibaraki 305–8506, Japan
2. The Yaeyama Mainichi Shimbun, Ishigaki, Okinawa 907–0004, Japan
3. Spotter Ishigaki Nature Guide Service, Ishigaki, Okinawa 907–0004, Japan
4. Department of Natural History Science, Graduate School of Science, Hokkaido University, Sapporo 060–0810, Japan