Meiosis and reproductive strategy in the parthenogenetic gall wasp Diplolepis rosae (L.) (Hymenoptera, Cynipidae)

Abstract

With refined cytological techniques the meiotic process in the female of the parthenogenetic gall wasp Diplolepis rosae is reexamined. Oogenesis is normal and 2n = 18 is restored in the unfertilized egg by the fusion of the division products of the haploid female pronucleus. In the presence of 15 nurse cells, pachytene in the female is followed by a diffuse stage in which the bivalents become extended into Feulgen‐(Giemsa) positive lateral loops. The parthenogenetic system could be classified as obligate homozygous automictic deuterotoky. Spermatogenesis in the rare males is briefly discussed. There are indications that the males are cytologically diploid but functionally haploid due to heterochromatization of a whole genome. © 1980 Mendelian Society of Lund