Background: Caddisflies have significant roles in freshwater ecosystems. Morphological identification is the major impediment in accurate species identification of Hydropsychids. Mitochondrial and nuclear markers are suitable for molecular systematics of these group of arthropods.
Methods: Trichopteran specimens of Lavasan District in northeastern Tehran, Iran were collected in 2012, and described using the morphological and molecular characters of mitochondrial cytochrome c oxidase subunit I (mt-COI) and three expansion fragments of large subunit (LSU) nuclear ribosomal DNA (28S rDNA) D1, D2, and D3. The resemblance of the specimen sequences was obtained by conducting BLAST searches against the GenBank database and by using simple maximum likelihood clustering using COI, D1, D2, D3, and combination of D1-D2-D3 sequence data sets.
Results: Based on morphological traits the specimens were resembled to Hydropsyche sciligra however there were no its counterpart sequences in the GenBank. Due to lack of unique group of data set for each gene fragment, the specimens were associated with different taxa on molecular phylograms. The sequence contents of the COI, D1, D2, D3, and D1-D3 regions clustered H. sciligra with H. brevis, H. angustipennis, H. occidentalis, H. hedini, H. grahami, and H. longifurca/H. naumanni, respectively.
Conclusion: Phylogenies obtained from combination of D1-D3 showed the highest bootstrap values for most of clades suggesting that long LSU-rDNA potentially is more useful for understanding phylogenetic relationships of caddisflies. A large-scale molecular and zoogeographic study on trichopteran species is suggested to revise and to develop the current knowledge of the caddisfly fauna and distributions in the country.
Keywords: COI; Caddisflies; Hydropsyche sciligra; LSU rDNA; Molecular systematics.