1. Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501, Japan
2. Faculty of Informatics, The University of Fukuchiyama, 3370 Aza-Hori, Fukuchiyama, Kyoto 620-0886, Japan
3. Department of Biology, Waseda University, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480, Japan