干旱区生态环境知识资源中心

To determine the degree of within-population diversity of a parthenogenesis-inducing Wolbachia symbiont in the parasitic wasp Trichogramma kaykai Pinto, Platner & Stouthamer, we established >200 isofemale lines of this (partly) parthenogenetic species from the Californian Mojave Desert. These were screened with Wolbachia-specific polymerase chain reaction primers. An infection rate of 12.4% was found. We then generated 45 DNA sequences for the ftsZ gene and compared these with 19 sequences from other Trichogramma species. We found a single nucleotide position diagnostic for the T. kaykai symbiont. Phylogenetic analyses indicated that this diagnostic position is a derived character and that all the Wolbachia symbionts in T. kaykai are very closely related; this suggests that all of them originate from a single, ancestral infection.