Development of silver stained structures during spermatogenesis in different genera of Formicidae

Abstract

Development of silver stained structures during the spermatogenesis of Tapinoma nigerrium, Pheidole pallidula, Tetramorium caespitum, Tetramorium semilaeve, Lasius niger and Plagiolepis schmitzii are studied. Nucleolar masses are only observed in early prophase. Obvious NORs are present in metaphase in all genera and species studied. However, there are no nucleolar Ag precipitates after metaphase. A resumption of silver stainability occurs in round spermatids. The majority of these genera present differential activity between the existing NORs. In T. nigerrimum there is primary or secondary NOR activity in all chromosomes of the complement, although there are interpopulation differences in relation to the NOR activity. In the remaining genera only certain chromosomes present NOR activity. Interpopulation genetic differences and environmental factors can cause differential activity of secondary NORs as observed in Tapinoma nigerrimum.

Supernumerary chromosome segments in different genera of formicidae

“…Silver staining showed the existence of a prio mary NOR in chromosome 6 and another in the segment carrier chromosome 8 as in the standard males ( Fig. These two techniques were also used in the previous studies of the NOR activity in standard males (Palomeque et al, 1990a). The same results have been obtained using the techniques described by Howell and Black (1980) and Rufas et al, (1982).…”

“…We have studied eleven different species of ant in previous papers (Palomeque et al, 1987(Palomeque et al, , 1988(Palomeque et al, , 1990(Palomeque et al, , 1990aPalomeque, Chica & Diaz de la Guardia, 1990b) and here. We have found five cases of chromosomal polymorphisms by supernumerary segments, a type of polymorphism not hitherto described in ants.…”

“…In T. nigerrimum there is primary or secondary NOR activity in all chromosomes of the complement, although there are interpopulation differences in relation to the NOR activity (Palomeque et al, 1990a). Two primary active nucleolar organizer regions (NORs) located in chromosomes 6 and 8 are usually observed.…”

Spermatogenesis in the parasitoid Diachasmimorpha longicaudata (Hymenoptera: Braconidae)

“…Gametes are therefore produced by normal meiosis in females, and by an altered meiosis, similar to mitosis, in males (Patterson and Porter ; Dreyfus and Breuer ; Crozier ; Palomeque et al . ).…”