Achiasmatic male meiosis in Cimex sp (Heteroptera, Cimicidae)

Chromosomes and their behaviour in spermatogenesis in Cimex species (Heteroptera, Cimicidae) from a bat species Myotis emarginatus were studied by using both a conventional staining method and sequence-specific fluorochromes CMA(3) and DAPI. Spermatogonial metaphase revealed 28 auto-somes, one large Y chromosome and four small X chromosomes. The Y was almost fully C-band positive as well as most telomeres of autosomes. The same regions appeared to be CMA(3) and DAPI positive, indicating that in heterochromatin GC-rich clusters are dispersed within AT-rich repeats. In meiosis homologous chromosomes in bivalents are physically associated with one or seldom two sites or collochores, i.e. meiosis is achiasmatic. In MI cells chromosomes in bivalents were aligned in parallel, but at early AI bivalents open out and chromosomes move to the poles one telomere foremost. Meiosis is post-reductional for the sex chromosomes.