Parthenogenesis-inducing microorganisms in Aphytis (Hymenoptera: Aphelinidae).

Production of males in uniparental lines of two species in the parasitic wasp genus Aphytis was induced by rifampicin, and male sexual functioning was determined. Wolbachia-specific 16S rDNA primers were used in a PCR in order to: (1) assess correlation between thelytokous reproduction and the presence of Wolbachia; (2) detect the loss of Wolbachia DNA in uniparental A. lingnanensis following antibiotic treatments, with or without the presence of a host; and (3) clone and sequence part of the Wolbachia 16S rDNA from the uniparental Aphytis species for phylogenetic studies. Males produced viable sperm that was transferred to the female spermatheca following mating. However, sperm failure to effect egg fertilization resulted in all-male progeny. Wolbachia were found in the two uniparental (A. lingnanensis and A. diaspidis) but not in the two biparental (A. lingnanensis and A. melinus) Aphytis lines tested. They can be detected in wasps up to 7 days following antibiotic treatments, regardless of the presence of host. The 16S rDNA for the symbionts in the two Aphytis species is virtually identical, and is most closely related to the Wolbachia found in Muscidifurax uniraptor (Pteromalidae).