Natalia V. Golub
Zoological institute, Russian Academy of Sciences, Universitetskaya nab., 1, St. Petersburg, 199034, Russia
Spermatogenesis including meiotic and sperm formation patterns was studied in nine species of Psocoptera based on AgNOR and C-banding techniques.
AgNOR procedure permitted revealing that very species had one nucleolus connected with an autosomal bivalent. Psocoptera were shown to share the NOR location pattern with Psylloidea and Heteroptera, but not with Aphidoidea, which are characterized by NORs located in sex-chromsomes.
In Psococerastis gibbosus (Sulz.) the largest block of C-heterochromatin was observed in X-chromosome, whereas small blocks – in six of eight autosomal bivalents, two bivalents showing no blocks. In this C-heterochromatin distribution pattern Psocoptera are similar to other Paraneoptera, in which as a rule only specialized chromosomes, including sex-chromosomes display the greatest heterochromatin amount.
Using AgNOR procedure the early spermatids were found to have a pair of centriolar adjuncts in all studied species. C-banding revealed one filament, however, also two adjuncts in Metylophorus nebulosus. Within Paraneoptera, Psocoptera are shown to be similar to Anoplura as regards the paired centriolar adjuncts.