Ayumi Matsuo1, Hiroshi Tomimatsu2, Jun-Ichirou Suzuki3, Tomoyuki Saitoh4, Shozo Shibata5, Akifumi Makita6, Yoshihisa Suyama7. 1. Field Science Center, Graduate School of Agricultural Science, Tohoku University, Osaki, Miyagi 989-6711, Japan Faculty of Bioresource Sciences, Akita Prefectural University, Akita 010-0195, Japan matsuo-a@akita-pu.ac.jp. 2. Department of Biology, Yamagata University, Yamagata 990-8560, Japan. 3. Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan. 4. Tohoku Research Center, Forestry and Forest Products Research Institute, Morioka 020-0123, Japan. 5. Field Science Education and Research Center, Kyoto University, Kyoto 606-8502, Japan. 6. Faculty of Bioresource Sciences, Akita Prefectural University, Akita 010-0195, Japan. 7. Field Science Center, Graduate School of Agricultural Science, Tohoku University, Osaki, Miyagi 989-6711, Japan.