Chironomisds (Diptera, Chironomidae) of upper part of Cheptsa river on Udmurt Republic territory: an ecological and faunistic review

The characteristic structure of benthic communities and benthic invertebrates drift in the riffle of the upper stream of lowland middle river is described. There are dynamics of changes of qualitative and quantitative parameters of zoobenthos and syrton from July to September. The significance of chironomids in benthic communities structure and syrton of the riffle is assessed. Given the taxonomic list of the chironomids of the upper stream of Cheptsa River, including 90 species and forms of the 4 subfamilies. The most impor-tant forms in the structure of zoobenthos of the riffle were species Thienemannimyia fusciceps and Polypedilum scalaenum. Composed of syrton most abundant chironomid species was forms inhabiting the overlying pool - Cricotopus bicinctus, Thienemanniella majuscula and Tvetenia tshernovskii, as well as the form inhabiting the riffle - Thienemannimyia fusciceps. The decline in the proportion of chi-ronomids of the benthic communities species richness from summer to autumn was accompanied by in-crease of abundance and biomass. The proportions of chironomids in the qualitative and quantitative pa-rameters of syrton decreased from summer to autumn. Migration activity of chironomids were highest in the evening twilight and the first hours of the night (21.00-00.00), but larvae and pupae of most species were observed in the benthic invertebrate's drift during all daily series.