Karyotypes and COI Gene Sequences of Chironomus agilis2, Ch. balatonicus, and Camptochironomus tentans (Diptera, Chironomidae) from Kurchatskoe Lake, Tyumen Region, Russia

Abstract

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.

Karyotypes and COI Gene Sequences of Chironomus annularius Sensu Lato (Diptera, Chironomidae) from Russia, Mongolia, and Armenia

“…The results showed that the studied taxon is the species complex. Usually, species and larval forms are confined to the type of water bodies or specific environmental conditions [43][44][45]. In reviewing the literature, Spies and Saether [1] found that larvae of C. annularius sensu lato are found in water bodies of various types, including small freshwater bodies, the profundal zone of lakes, and saline waters such as the Baltic Sea littoral, and are widely spread geographically; it could be that different species were identified as C. "annularius".…”

“…It is known that Chironomus has high variability at the chromosomal and biochemical levels of organization, allowing it to inhabit various types of water bodies [8,43,[46][47][48]. The cytogenetic distances between two distant reservoirs (for example lakes with similar conditions) can be minimal, and vice versa, the distances between two neighboring reservoirs (for example a lake and a river) can be very large, with karyoforms even arising [43][44][45].…”

Aquatic Biodiversity: Evolution, Taxonomy and Conservation

“…Four papers are about the taxonomy, phylogeny and phylogeography of invertebrates. Bolshakov et al [3] presented the results of the identification of the cryptic Chironomus species based on an integrative approach that included morphological, cytogenetic, and molecular genetic methods in highly mineralized Kurchatskoe Lake (Russia, West Siberia). In general, three Chironomus species were revealed.…”

The first record of Chironomus nuditarsis Keyl, 1961 from Sevan Lake (Armenia) confirmed by morphology, karyotype and COI gene sequence

“… markosjani Shilova, 1983 ( Shilova 1983 ), which is probably a sibling species to Ch. annularius Meigen, 1818 ( Bolshakov et al 2023 ), inhabiting depths of 10–20 m; Ch. piger Strenzke, 1959 and Ch.…”

“…Unfortunately, we did not have the opportunity to collect more samples of this species. We regularly suggest to use a comprehensive approach to the species identification of the genus Chironomus , which includes morphology, cytogenetics and molecular genetics ( Bolshakov and Movergoz 2022 ; Bolshakov et al 2022a , 2022b ). In this study, we have decided to use a single Chironomus larva to obtain a complex of scientific data.…”