Wolbachia having no effect on reproductive incompatibility in Tetranychus kanzawai KISHIDA (Acari: Tetranychidae)

Unidirectional incompatibility is known in the kanzawa spider mite, Tetranychus kanzawai KISHIDA. Crosses between females from kudzu and males from either tea, pear or hydrangea were incompatible and resulted in no female offspring, while the reciprocal crosses were compatible and produced normal progeny with a female-biased sex ratio. Of these populations, the tea, pear and hydrangea populations were found to be infected with Wolbachia, which has been previously shown to alter reproduction in arthropods. Wolbachia was identified using PCR assays for a 770-bp fragment of the ftsZ gene and an 890-bp fragment of the 16S rDNA. Compatibility between females from the kudzu population and males from either of the antibiotic-treated tea, pear or hydrangea populations was not restored even when the latter were treated with tetracycline and rifampicin. PCR assays did not reveal any Wolbachia DNA in mites that were treated with antibiotics. Therefore, I: kanzawai appears to harbor a neutral strain of Wolbachia which does not cause the incompatibility seen in Drosophila spp.