Evolution of parthenogenesis in the otiorhynchus scaber complex

Abstract

A new approach for estimating genetic identity values was applied to a data set on allozyme variation in the weevil, Otiorhynchus scaber (Coleoptera: Curculionidae). This species complex contains sexuals and different races of polyploid asexuals. The results were used to reanalyse the phylogenetic relationship among races and to discuss the monophyletic versus the polyphyletic origin of parthenogenesis. A polyphyletic origin of parthenogenesis was suggested based on the assumption of hybridization between related species, and the extinction of an ancestral species. The genetic diversity among the different races was compared. A decreased number of new mutations with increased ploidy level was found among current populations. This correlation was explained by a lower evolutionary rate in polyploid asexual races than in diploid sexual races. © 1992 The Genetical Society of Great Britain.