On the cytology of two species of Necrobia (Oliv.) (Coleoptera: Cleridae)

Abstract

The karyology of Necrobia ruficollis F. and Necrobia rufipes De Geer was investigated. The male karyotype of the species is 18♀:8+Xyp. Details of structure and behaviour of chromosomes during cell division are presented. Variations in the morphology of chromosomes in Necrobia species and trends in the evolution of karyotypes in the Cleridae are discussed.Key words: Cleridae, karyotype, sex chromosome mechanism, polyphaga, pericentric inversion.

Astylus variegatus (Coleoptera, Melyridae): Cytogenetic study of a population exposed to agrochemical products

“…Chromosome evolution involving diploid number reduction is evident not only in A. variegatus, but also in all previously studied species of the superfamily Cleroidea (Smith and Virkki, 1978;Yadav and Dange, 1989). The karyotype with 2n = 16+Xy p of A. variegatus is shared with all 12 related species of the family Cleridae, but it is the first time that it is reported among Melyridae.…”

“…In species of Cleroidea, it was only reported in Enoclerus sp. and Necrobia ruficolis (Virkki, 1963;Yadav and Dange, 1989). In Coleoptera, biquiasmatic bivalents seem to be more frequent in species which present chromosome differentiation through fusions, such as representatives of the family Elateridae (Smith, 1956a;Agarwal, 1962;Kacker, 1963;Ferreira et al, 1984;Yadav and Vyas, 1994).…”

“…The chromosome morphology has been reported for six Cleridae species: Enoclerus sp., Necrobia ruficollis, Necrobia rufipes, Priocera spinosa, Thanasimus formicarius, and Trichodes apiarius. All these species presented exclusively meta/submetacentric chromosomes (Virkki, 1960(Virkki, , 1963Smith and Virkki, 1978;Yadav and Dange, 1989). In contrast, the three studied species of the family Melyridae, which includes A. variegatus, presented different karyotypes: Endeodes collaris showed 2n = 18+X0, Collops sp.…”

“…This superfamily comprises around 10.000 species included in eight families (Lawrence and Newton, 1995;Costa, 2003). Cytogenetic data, however, are restricted to 15 Cleroidea species of two families, Cleridae and Melyridae (Smith and Virkki, 1978;Yadav and Dange, 1989).…”

Cytogenetic analysis of Astylus antis (Perty, 1830) (Coleoptera, Melyridae): Karyotype, heterochromatin and location of ribosomal genes

“…The 12 species of Cleridae, distributed among five genera ( Enoclerus , Priocera , Thanasimus , Trichodes and Necrobia ), exhibit karyotype uniformity, i.e. , 2n = 18, the basal sex determination system for Coleoptera, Xyp, and meta/submetacentric morphology for all chromosomes ( Smith, 1953 ; Virkki, 1963 ; Smith and Virkki, 1978 ; Yadav and Dange, 1989 ; Schneider et al , 2007a ). However, the four species belonging to the family Melyridae display differences both in their chromosome number and their sex determination system ( Smith and Virkki, 1978 ).…”