Most social Hymenoptera are characterized by simple haploid sex determination and environment-based caste differentiation. However, recently, reproduction and caste determination systems by genetic factors have been reported in some ants. Particularly the case of the little fire ant Wasmannia auropunctata is remarkable. In this ant, female sexuals are produced by ameiotic parthenogenesis from unfertilized eggs, workers from fertilized eggs, and males from fertilized eggs after the elimination of the maternal genome. They mean a complete separation of male and female gene pools. The special reproductive system will give us new approach to test the theoretical hypotheses of the evolution of sex and sociality. Similar clonal reproductive system was discovered in myrmicine ant Vollenhovia emeryi. This species is queen-polymorphic, long-winged and short-winged queens. The two queen types are adaptation as dispersal and mating strategies. Probably the clonal reproductive system in V. emeryi has evolved associating with the queen polymorphism. In this presentation, we introduce the system of clonal reproduction in this ant, and propose the hypotheses for the evolutionary process and factor of clonal reproduction from the life history data. Additionally we have discussion about the existence of female-male conflict in sexual production in this ant.