The distribution and activity rhythm of the important blood-sucking insects (Diptera) along the Qinghai-Tibet railway line from Gerrmu to Tanggula Mountain

The distribution and activity rhythm of the important blood-sucking insects (Diptera) along the railway line from Gerrmu to Tanggula Mountain was studied with person-trapping, tent-trapping, livestock-trapping, lamp-trapping and net method. The results indicate that there are 4 families, 8 genera, and 52 species of blood-sucking insects (Diptera) were observed in this survey. Among them, 3 genera and 9 species of Culicidae, 2 genera and 24 species of Ceratapogonidae, 4 genera and 10 species Of Tabanidae, 1 genus and 9 species of Simuliidae; Dominant species are L. (H. tuotuoheensis in Tuotuohe, L. (H. tuotuoheensis and Hy. zaitzevi in Nachitai, C. modertus, A. flavidorsalis, L. (H.) geermuensis, Hy. zaitzevi, S. (W.) equinum, and S. (W.) wushiense in Gerrmu. As altitude is different, the composition of population of blood-sucking Diptera is also different, divergence of distribution is obvious and a dramatic disparity showed in density index of these species. The composition of species is the unique distribution characteristics of plateau, I with the increase of altitude, its’ quantity increases progressively and the species involved changes from complex to simplicity. The composition I density, flight time, rhythm of seeking food of the blood sucking Diptera insects varied with geographical sites and altitudes. Most of them act diurnally, few nocturnal species were observed. Culex and Culicoides mainly act in dawn and nightfall, while Aedes, Leptoconops, gadflies and blackflies mainly act from 10 a.m. to 6 p.m. In Gerrmu, mosquitoes, midges, gadflies and black flies mainly appeared from April to October, the appearance peak of midges is May, June of mosquitoes, July of gadflies and blackflies. The observations provide with basis to control mosquitoes, midges, gadflies and blackflies reasonable in the areas.