| Co-Investigator(Kenkyū-buntansha) |
WATANABE Yasuaki Laboratory of Entomology, Tokyo University of Agriculture, 農学部・昆虫学研究室, 助教授 (70078096)
NISHIKAWA Yoshiaki Biological Laboratory, Chtemon-Gakuin University, 生物学研究室, 教授 (90079385)
ISHIKAWA Kazuo Biological Laboratory, Matsuyama Shinonome Junior College, 生物学研究室, 教授 (30071682)
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| Research Abstract |
1. The upper hypogean fauna was examined throughout the Japanese Islands with the exception of the Ryukyus and the northern part of Hokkaido. It was found that the specialized fauna exists at least as far north as the Oshima Peninsula of southwestern Hokkaido and as far south as the southern central part of Kyushu. However, the eyeless animals extant in the upper hypogean zone of Hokkaido are not the same as the true cave animals but are essentially identical with endogean forms (Ueno,1987). A similar result was obtained in the northernmost part of Honshu. This accords well with the result of cave investigations, which seems to indicate that true terrestrial cavernicoles exist only in a limited part of the temperate zone.
2. The so-called troglobionts are widely distributed in the upper hypogean zone of the three southern main islands of Japan, with the exception of pure granitic terrains and alluvial plains. The mode of their differentiation is the same as that already known about cave inhabitants. It was surmised that reproductie isolation between them had been completed by the existence of such barriers as pure granitic zones, impenetrable layers, high phreatic levels, and so on.
3. It was proved that endemic species of terrestrial troglobionts could have become differentiated in very young isolated lands formed after the Last Interglacial Age (Ueno, 1988; Nishikawa, 1987). These are the sure proof that the so-called troglobionts are much more recent than they were formerly believed.
4. A review was published on the process of development of biospeological studies, concluding that the upper hypogean zone must be the native habitats of most terrestrial troglobionts (Ueno, 1987).
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