- 著者
- Yuki OKADA Takashi YABE Sen-Ichi ODA
- 出版者
- The Herpetological Society of Japan
- 雑誌
- Current Herpetology (ISSN:13455834)
- 巻号頁・発行日
- vol.30, no.1, pp.53-61, 2011 (Released:2011-07-01)
- 参考文献数
- 27
- 被引用文献数
- 3
We investigated sex ratio in seven populations of the Japanese pond turtle, Mauremys japonica, inhabiting ponds in the central region of Aichi Prefecture, Japan. The sex ratio, calculated as a numerical proportion (%) of males to total individuals sexed, was highly variable among the populations, ranging from no more than 20.0% to no less than 92.9%. Since M. japonica shows a temperature-dependent sex determination (TSD) with eggs producing more males under a relatively low incubation temperature and more females under a higher temperature, we hypothesized that the observed remarkable inter-population variation in sex ratio reflects that in the nest temperature. Our field observations indicated that the nesting sites of male-biased populations were largely shaded by wood, thus supposedly under a relatively low ambient temperature, while those of female-biased populations were located in open environments with direct exposure to solar heat. These results offer a circumstantial support to the above hypothesis. Remarkably skewed sex ratios observed in some populations might reflect the effect of substantial habitat fragmentation and severe nesting site limitation caused by recent artificial land development and changes in agricultural land use. If this is actually the case and the effect continues to operate, many of the M. japonica populations may eventually disappear.
- 著者
- Akio Shinohara Shin-ichiro Kawada Masashi Harada Kazuhiro Koyasu Sen-ichi Oda Hitoshi Suzuki
- 出版者
- 日本哺乳類学会
- 雑誌
- Mammal Study (ISSN:13434152)
- 巻号頁・発行日
- vol.33, no.2, pp.77-82, 2008 (Released:2009-07-04)
- 参考文献数
- 39
- 被引用文献数
- 9