Abstract :
In this paper, we propose an alternative to inclusive fitness in kin selection models. The key point is to show that kin selection in family-structured models can be put into a context of fertility selection. First, we extend T. Nagylaki′s (1987, Genetics115, 367-375) result on approximate adaptive topographies in two-sex populations under weak selection by considering sex-differentiated fertilities of matings. The result is that the change in the geometric average and in the arithmetic average of the mean fertilities in male and female offspring is approximately equal to the additive genetic variance in fertility. Then we show that fertility-viability selection models and kin selection models with sex differences are special cases if appropriate fitness parameters are introduced and if genotype frequencies are considered at an appropriate time of the life cycle. Kin selection models with partial adoption of offspring giving rise to frequency-dependent selection are also studied.
