八ケ岳におけるノミの生態学的研究 : (II)低山帯の小哺乳類に見出されたノミについて

抄録

The results are given of a survey of the fleas from the small mammals living in the mountain zone of the Yatsugatake range, Nagano Prefecture, Japan, carried out during the period between November, 1965 and October, 1966. The 391 catches of small mammals comprised 60.4 percent of Apodemus argenteus, 11.8 percent of Clethrionomys andersoni, 8.4 percent of Dymecodon pilirostris and 5 other species which included the mouse, voles and insectivores (Table 1). This species composition was considered as characteristic of the transition zone between the mountain and subalpine forest zones of Central Honshu. Fourteen species of fleas were recorded from the hosts mentioned above (Table 2). A few fleas obtained in small number could not be clarified as to their seasonal occurrence or true hosts. Among others, the seasonal occurrence of P. nippon differed from that observed in the subalpine forest zone (cf. UCHIKAWA, 1967) ; and N. sasai and C. c. congeneroides seemed to occur throughout the year. Some fleas exhibited more remarkable limitations in the vertical distribution than their host species. Taking into account the informations on the range of each flea, interpretations of the host relationships of the fleas were made. In the relationships between the fleas of a common genus, a tendency of the isolation in ranges of two or more species was observed as well as the differences in the host preferences and seasonal occurrences.