On the evolution of parthenogenesis. II. Inbreeding and the cost of meiosis.
Quantitative models of genetic change were analyzed to study the effect of inbreeding on the conditions for the evolution of parthenogenesis. Inbreeding does not greatly change the cost of meiosis in diploids and actually increases it is haplodiploids. Inbreeding increases parent-offspring relatedness and the reproductive value of females. These direct effects act antagonistically on the cost of meiosis: higher relatedness between parents and biparentally-derived offspring promotes biparental reproduction, and high reproductive value of females promotes thelytoky. In diploids the two effects cancel one another, while in haplodiploids the latter predominates. A high proportion of haplodiploid species that undergo close inbreeding have thelytokous relatives. Apart from its effect on the sex ratio, inbreeding directly promotes parthenogenesis in haplodiploids. -from Author