横断山区昆虫区系初探

1981—1984年,中国科学院青藏高原科学考察队在我国西南部的横断山区进行了大规模的多学科综合考察,收集昆虫标本17万多号.横断山区特殊的自然地理条件孕育着独特的昆虫区系.种类繁庶、成分复杂,特有种,尤其高山特有种相当丰富,物种分化显著,并具有地域上的狭布性,构成本区昆虫区系特征.作者根据古北、东洋、高山特有三种主要成分的分布,试提出古北、东洋两大区系在本区的分异界线.典型东洋区系成分一般限于海拔2,800—3,000m以下地区,约与亚热带常绿阔叶林分布上线一致.

PRIMARY DISCUSSION ON THE FAUNA OF HENGDUAN MOUNTAINS, CHINA

The Hengduan Mountains are situated in the southeastern edge of Qinghai-Xizang Plateau of China. They are famous because of the high mountains and deep valleys placed side by side from north to south and with more cliffed peaks and much more narrowed valleys. In such special geographical conditions there have been developing the specialized insect fauna. The longitudinal mountains are favoured by Palaearctic elements extending to the south, the lower valleys make Oriental components possibly push to the north. The intensified speciation caused by geographical and ecological isolation is the important factor for the composition of the flourished species. Therefore, the converged alpine members and constricted distribution of species constitute the specialized faunistic characteristics. It is somewhat different from the west main part of Qinghai-Xizang Plateau according to its topographical feature and insects fauna. Based on the distribution of the main Palaearctic, Oriental and endemic alpine species, a boundary between the Palaearctic and Oriental regions has been primarily given as in fig. 3. The west and north of this line belong to Palaearctic region, the opposites belong to Oriental. The typical species of Oriental region are mainly distributed below the altitude of 2800-3000 m. The boundary between Palaearctic and Oriental regions somewhat corresponds with the limit of evergreen broad forest distributed in this area.