Fauna Composition And Distribution Pattern Of The Darkling Beetles Of The Hengduan Mountains Region (coleoptera: Tenebrionoidea)

The Hengduan Mountains Region is situated in the east of Xizang, west of Sichuan and northwest of Yunnan provinces in China. Most part of this region is characterized by a series of parallel high mountains and deep gorges from north to south. The special physical conditions impregnate the rich flora and fauna with active species differentiation. The taxonomy of darkling beetles fauna of this Region is inadequate. Based on the date from literatures and the results of identifying specimens deposited in Hebei University Museum and other research institutes and collected by author and his colleagues from the field, we systematically summarize the fauna composition and distribution pattern of tenebrionids in this Region. The dissertation contains 110 thousand words. The main research results are listed as follows:1. 383 species and subspecies lying in 62 genera, 24 tribes, 6 subfamilies are recorded. The diagnosis of family, subfamilies, tribes and genera are given, as well as the cited literatures, distribution, information of material examined for each species. The keys to subfamilies, tribes, genera and species are provided.2. Total number of tenebrionids of this Region accounted for 22.5 % of China, accounting for 75.1 % of Qinghai-Xizang Plateau. The subfamily Tenebrioninae has the most abundant species, followed by the subfamily Lagriinae. The tribe Blaptini contains the most abundant genera, followed by the tribes Statirina and Cnodalonini. The genus Laena contains the most abundant species, followed by the genera Asidoblaps and Agnaptoria. The arboreal darkling beetles diversity is richer than soil darkling beetles.3. In the zoogeographical regions of China, Southwest China region type shows the highest proportion, Tibet-Qinghai and Central China region types separately take the second and the third place; The Hengduan Mountains Region Shares more species with Taiwan than Hainan. In the zoogeographical regions of the world, Oriental region species are dominant, Palaearctic region species are followed. The darkling beetles fauna of this Region closely connects with the fauna of its surrounding areas, it is the closest to the fauna of Central China and South China regions; it shows a closer relationship with the fauna of the Indo-China peninsula than with the fauna of Indian peninsula.4. The darkling beetles fauna of this Region composed of 4 faunal elements, Oriental elements are dominant, Palaearctic ones next and Eurytopic ones last. The endemic elements, which including 214 species, possessing 55.9 %, are remarkably abundant. The basic characteristics of the fauna as follows: the dominant position of Oriental elements, the abundant blending of Palaearctic and Oriental elements, rich in endemic species, alpine species and stenotopic species, the active zone of species differentiation.5. The results of modern distribution pattern analysis shows that the darkling beetles fauna mainly distribute in area from southwest to northeast of this region. Typical Oriental elements distribute in the eastern and southwestern parts of the gorges of this Region, some groups may advance to the north through deep gorges; Typical Palaearctic elements distribute in the western and northern parts of the high plateau of this Region, some groups may spread further to the south, but always confined to the high altitude mountains; The Palaearctic and Oriental faunas overlapped with each other.6. After studying the vertical distribution pattern of the richness on darkling beetles, the analysis revealed the following results: The species richness gradually increased and then decreased with the rise of altitude, the subtropical evergreen broad-leaved forest zone has the most abundant species; The Oriental and Eurytopic species richness separately gradually decreased with the rise of altitude, the valley bottom shrubby zone and the evergreen broad-leaved forest zone have the most abundant Oriental species; The Palaearctic species richness gradually increased and then decreased with the rise of altitude, the subalpine dark coniferous forest zone has the most abundant species. The mountain broad-leaved and coniferous forest zone is the transition zone between the Oriental and Palaearctic species. The endemic species mainly distribute in the evergreen broad-leaved forest zone, the broad-leaved and coniferous forest zone and the dark coniferous forest zone, the last one has the most abundant species.7. The faunal origin of darkling beetles of this Region includes the following 3 aspects: 1) Evolution on the basis of palaeo-fauna; 2) The Oriental elements advance to the north through deep gorges; 3) The Palaearctic elements from the north disperse to the Hengduan Mountains Region. The Cangshan Mountains in Dali district, the Gaoligong Mountains in Nujiang district, the Yulongshan Mountains in Lijiang district, the Habashan and Xushan Mountains in Zhongdian county, the Baimaxueshan and Meilixueshan Mountains in Deqen county, the Daxueshan Mountains in Kangding county, the Qionglaishan Mountains in Lixian county are the active zones of species differentiation.