Incompatibility and host plant differences among populations of Tetranychus kanzawai Kishida (Acari: Tetranychidae)

Reproductive incompatibility is known to occur in Tetranychus kanzawai. K strain females were found to be incompatible with T strain males, i.e., a cross between K strain females and T strain males resulted in only male progeny, whereas the reciprocal cross resulted in a higher egg hatchability but in a reduced sex ratio. To determine whether T. kanzawai populations collected from different localities belonged to either the T strain or the K strain, 74 local populations were tested. Of these populations, eleven belonged to the IC strain and the others belonged to the T strain. Wolbachia infection occurred in local populations belonging to both the T and K strains. As all of the infected populations harbored a Wolbachia strain which does not influence compatibility of the host, Wolbachia is not responsible far the incompatibility between the T and K strains. Host plant specificity varied among local populations. Some populations successfully matured on tea, some attained maturity on hydrangea, and some were unable to develop on either tea or hydrangea. Thus, a! wide range of genetic divergence was observed in T. kanzawai.