Chironomus plumosus (Linnaeus)

Michailova, Paraskeva, 2024, Markers in the polytene chromosomes of freshwater Chironomus Meigen (Diptera, Chironomidae) species, Zootaxa 5453 (4), pp. 511-537 : 523

Chironomus plumosus (Linnaeus)

The chromosome set is 2n = 8. Two chromosomes AB and CD are metacentric, EF—submetacentric and G chromosome is telocentric. The centromere regions of all chromosomes are distinct ( Fig. 11 ). The arm A is with inverted sequences (A2.2). The species has four BRs—three in chromosome G and one in chromosome arm B. The homologues of chromosome G are unpaired. The NOR of chromosome G is near to the centromere region. Between the BR, located near to the NOR and the other BR there is a narrowing of the chromosome and many dark and light bands ( Fig. 11 )—markers of the species. The species is highly polymorphous, characterized by the presence of a polymorphous system of inversions which involved the transition of a standard homozygous type of the karyotype through heterozygotization into another homozygous type ( Michailova 2014). This author reported for an additional B chromosome in Bulgarian populations ( Fig. 11 ). Four hundred and two individuals were studied.

Collection sites: Sofia: Pancharevo Lake , Russe —fish pool Mechka, Burgas — Atanasovsko Lake, Durankulak Lake , Balchik—temporary water basin.

Figures

FIGURE 11. Polytene chromosomes of Chironomus plumosus. The numbers on the chromosome arms indicate the “basic”sequences.The large arrows show the localization of the centromere region. The small arrow on chromosome G indicates the marker sequences required for species identification. BR—Balbiani Ring, NOR—Nuclear Organizer Region. A, B, C, D, E, F, G—arms of the chromosomes. Scale bar, 10µm.