Environmental agents in Lake Łuknajno (Poland) affecting the genome of Chironomus melanotus Keyl, 1961 (Diptera, Chironomidae) — a new species of Polish fauna

Chironomus melanotus Keyl, a new species of Polish fauna, is described on the basis of cytogenetic characteristics. It belongs to the cytocomplex thummi with the chromosome set 2n = 8, chromosome arm combinations AB CD EF G and species-specific karyotype markers.

Two types (somatic and inherited) of structural chromosome rearrangements in salivary gland chromosomes were identified in the species and somatic rearrangements (heterozygous inversions, deficiencies, deletions — Somatic index — 0.54) were observed for the first time in this species. In addition to those in the mosaic state, some genome alterations — trisomy and “B” chromosome, as well as larval malformations (10.27%) were detected for a first time. The malformations and somatic structural and genome aberrations may have been caused by different stress agents in the environment. Thus, we suggest that the high spectrum of somatic rearrangements observed in C. melanotus may indicate the existence of pollution (elevated Cd and Pb concentrations) in Lake Łuknajno (the study area) and perhaps trace metals and different chemicals produced by the Chara species.