Inversion polymorphism of non-biting midges Camptochironomus tentans (Fabricius) 1805 (Diptera, Chironomidae) from populations of the Lower Volga region and Central Caucasus

The karyotype of Camptochironomus tentans (Fabricius), 1805 (Diptera, Chironomidae) from the populations of the Lower Volga region and Central Caucasus (the northern macroslope) has been studied. In the karyotype of C. tentans from Saratov oblast, 14 banding sequences (BS), 13 genotypic combinations, and 14 zygotic combinations were identified. Four new BSs were described: ten B12, ten F4, ten F5, and ten G4, which are distinguished by simple paracentric inversions from those already known for the species. The chromosomal polymorphism belongs to the inversion type; its level in the Saratov population is generally the same as in populations of other parts of the area. The number of heterozygous inversions per specimen was 1.3; the number of heterozygous inversions per arm was 0.86; the percentage of heterozygous larvae was 84.5. The polymorphic arms in C. tentans were A, B, C, and F. Nine previously known BSs were revealed in the karyotype of C. tentans from Central Caucasus, and no new sequences were found. Arm B in C. tentans was polymorphic. The zygotic combinations in all the studied populations were distinct.