RESUMEN
A revision of mapping of main and alternative banding sequences in chromosome III (EF) has been made for 14 species of the Chironomus plumosus group. In total, new versions of mapping are presented for 18 banding sequences of arm E and 18 banding sequences of arm F. A new way of tracing the origins of banding sequences in chromosome III of the Ch. plumosus group in comparison with basic banding sequences of the genus Chironomus is suggested. The presented data indicate that h'pluE2 in arm E and p'borF2 in arm F are the closest to banding sequences of Ch. piger Strenzke, 1959 and thus should be considered the most ancient among banding sequences of chromosome III in the Ch. plumosus group. Phylogenetic relationships of banding sequences of chromosome III are discussed.
RESUMEN
Cytology and ecology of Chironomus (Chironomus) salinarius Kieffer, 1915 (Diptera, Chironomidae) was examined from material collected in the saline rivers of the Lake Elton basin (Volgograd region, Russia). Larvae of salinarius-type were identified as C. salinarius on the basis of their karyotype. The species is redescribed on the basis of all metamorphic stages. The reared imago and karyotype were obtained from larvae of the same population. The karyotype of C. salinarius, detailed mapping of the 5 chromosome arms A, C, D, E, F and characteristics of chromosome polymorphism are provided. Information on distribution and ecology of C. salinarius from the saline rivers (total mineralization 6.8-31.6 g l-1) of the Lake Elton basin is also given. Chironomus salinarius is a common in the saline rivers and occurs in sediments with high silt content. On the basis of recent samplings C. salinarius appears to be very abundant in saline, mesotrophic as well as in eutrophic rivers. Chironomus salinarius accounted for 49-66% of total abundance of zoobenthos in water with salinity up to 13-31.6 g l-1.
Asunto(s)
Chironomidae/clasificación , Larva/crecimiento & desarrollo , Pupa/crecimiento & desarrollo , Distribución Animal , Estructuras Animales/anatomía & histología , Estructuras Animales/crecimiento & desarrollo , Animales , Tamaño Corporal , Chironomidae/anatomía & histología , Chironomidae/crecimiento & desarrollo , Ecosistema , Femenino , Larva/anatomía & histología , Larva/clasificación , Masculino , Tamaño de los Órganos , Pupa/anatomía & histología , Pupa/clasificación , Federación de RusiaRESUMEN
The identity of Chironomus atrella Townes has been confusing because the name has been used for at least 2 quite different species. This situation is clarified karyosystematically by describing the banding patterns and chromosomal polymorphisms from a number of locations in Canada and the US. Most populations show only moderate levels of polymorphism (average heterozygosity, 0.36), although in some samples from shallow waters, the level of polymorphism is much higher (average heterozygosity, up to 0.92). The banding patterns of the polytene chromosomes are either identical or closely related to those found in Holarctic species with a northern distribution. These patterns and the distribution of inversions in the C. atrella populations are consistent with a progenitor that colonized North America across the Bering Strait and spread down the Rocky Mountain chain; at the same time, new gene combinations developed that allowed it to spread eastward over the majority of the continent.