Karyotypes and <i>COI</i> Gene Sequences of <i>Chironomus agilis</i>2, <i>Ch. balatonicus,</i> and <i>Camptochironomus tentans</i> (Diptera, Chironomidae) from Kurchatskoe Lake, Tyumen Region, Russia

Chironomids can inhabit a large variety of water bodies. They contribute to the process of biological purification of water bodies, and they are a high-quality food for commercial fish. Any comprehensive study of biodiversity in water bodies begins with the investigation of chironomids, which are typically variable and difficult to identify through morphology. Similar species are called sibling-species. For precise identification, we used a comprehensive approach, including morphology, cytogenetics, and molecular genetics. In one sample from Kurchatskoe Lake (Tyumen reg.), with mineralized water of 7‰, we found three Chironomus species. Karyological analysis revealed seven banding sequences in Chironomus agilis2, eight in Ch. balatonicus, and seven in Camptochironomus tentans. The combination of balD1.2 was found in all Ch. balatonicus larvae. All the found banding sequences are typical for the studied region, and have previously been recorded in European and Altai populations. All the estimated genetic distances of COI gene sequences in the studied larvae of each species are much lower than the commonly accepted threshold of 3% in species of the genus Chironomus