Abstract: 【Aim】 The aim of this study is to investigate the species and the distribution of aquatic flies in the camel-living environment in Alashan of Inner Mongolia, Northern China. 【Methods】 Aquatic flies were surveyed by sweeping nets in the camel-living environment from May to September in 2014. The COI gene sequences of blood-feeding spcies identified were sequenced and analyzed. 【Results】 Totally 47 species of 41 genera in 21 families of aquatic dipteran insects were found, among which 16 species are newly recorded in Inner Mongolia, and 12 are blood-feeding species. Among all the sampled species, individuals of the three suborders Nematocera, Aristocera and Brachycera accounted for 49.3%, 43.5% and 7.2% of the total individuals sampled, respectively. The results of molecular analyses showed that the nucleotide sequence identities of the COI sequences of 12 blood-feeding species range from 75.9% to 97.3%, and significant differences exist between different families in the same order as well as between different genera in the same family. 【Conclusion】 This study revealed essentially the species composition of aquatic flies in the camel living area of Alasan in Inner Mongolia, particularly the blood-feeding species, which may serve as the basis for the subsequent identification of the vectors of camel onchocerciasis.

Key words: Aquatic insects, Diptera, species composition, COI sequence, phylogeny, camel