Abstract
In three species of rice grasshoppers, Oxya japonica (Thunberg), O. chinensis formosana Shiraki and O. yezoensis Shiraki (Orthoptera: Catantopidae), most unfertilized eggs begin developing, but the viability of unfertilized eggs is much lower than that of fertilized eggs. The hatchability of unfertilized eggs is 17.8% in O. japonica, 10.4% in O. chinensis formosana and 5.4% in O. yezoensis. The number of larvae developing to the adult stage is 9.7% in O. japonica, 6.3% in O. chinensis formosana and 1.4% in O. yezoensis. Thus, the rate of embryonic development, hatchability and adult emergence in parthenogenesis is highest in O. japonica, and lowest in O. yezoensis. All larvae and adults produced by parthenogenesis are female. The number of chromosomes in parthenogenetic embryos of all the three species is 24 and diploid.
