翼手類における社会構造の類型とその展開

概要

論文の詳細を見る
1. The basic social patterns in the Chiroptera (bradbury, 1977) were reviewed, and only the inadequate or conflicting parts of each of the six categories were pointed out. 2. The basic social unit or central core in all of the social patterns is mother-young pair. Even in the solitary species, females tend to aggregate with each other, and give birth to young at certain breeding areas. 3. Bats showing reproductive periodicity or seasonal monoestry are inclined to form nursery colonies. Such colonies are commonly present in many bats, except for solitary and monogamous species. 4. Among the year-round multi-male/multi-female groups (E type), the bats at higher latitudes form male-free nursery colonies at parturition. This phenomenon suggests that E type may change into C type involving sexual segregation during lactation. 5. In many bats that roost externally on branches, conspicuous aggregation may be formed in order to support the defence against predators. On the other hand, many cave-dwelling bats form huge nursery colonies. The cause of this may be explained that they secure the caves providing shelter and/or serving as roost sites for large groups. 6. In the cave-dwelling bats, the young positively contact with each other and form dense cluster at roost sites. This property may play some part in the transition from loose colony type to dense colony one. 7. The number of females consisting of a harem is usually less than several tens. In the species forming year-round harems, sexual dimorphism is common, and males are typically bigger than females. 8. Seasonally variant social structures in temperate bats may be caused by the torpor in winter, seasonal monoestry, and delayed fertilization or delayed implantation. 9. Cave-dwelling bats form mixed species colonies in the seasons except winter. It is probable that each species composing a dense mixed group is in cooperation with the others as the individuals of the same species do in intraspecific relationship. 10. The evolution accompanied with the progress of flight ability is reflected in the social organiyation. A possible evolutional sequence of social patterns is as follows: solitary, monogamous families, harems, multi-male/multi-female groups, and Seasonally variant social aggregates.
1988-04-15

翼手類における社会構造の類型とその展開

スポンサーリンク

概要

著者

関連論文

スポンサーリンク