Transfection of Wolbachia in Lepidoptera:: the feminizer of the adzuki bean borer Ostrinia scapulalis causes male killing in the Mediterranean flour moth Ephestia kuehniella

Two species of Lepidoptera, Ostrinia scapulalis and Ephestia kuehniella, harbour Wolbachia, which are maternally transmitted intracellular bacteria that often cause reproductive abnormalities in arthropods. While the infection in O. scapulalis causes conversion of genetic males into functional females (feminization), that in E. kuehniella induces cytoplasmic incompatibility In the present study we investigated the relative importance or host and Wolbachia factors in the differential expression of reproductive alterations in these insects. We transferred the Wolbachia harboured by O. scapulalis to E. kuehniella in which the original infection had been cured by tetracycline treatment. The transfected strain of E. kuehniella expressed a maternally inherited, female-biased ses ratio. Unexpectedly two lines: of evidence suggested that the srs ratio distortion was due to malt, killing. First, higher mortality of young larvae was observes. Second, the removal of the transferred Wolbachia resulted in the recovery of a 1:1 sex ratio, whereas the removal of a feminizer should result in a male-biased sex ratio among offspring. To, the authors' knowledge, this is the first report that a single Wolbachia strain call cause two distinct sexual abnormalities in different hosts. Our observations highlighted the importance of host-Wolbachia interactions in determining the phenotype of reproductive alterations.