Available mathematical methods for analyzing the demography of plant and animal populations do not include the interactions of the sexes. The tacit assumption is usually made that the population contains sufficient males to fertilize all mature females, so that the dynamics of the population are determined by the abundance of the latter (this assumption is referred to as "female dominance"). This assumption is now known not to be universally true, and recent work has shown that including the sexes in demographic models can produce complicated and heretofore unexpected patterns of dynamics. This research will investigate these patterns, using mathematical methods developed for the study of nonlinear dynamical systems. The models to be studied will include age or size classes of both males and females, and the possibility of competition for mates among individuals of the same sex but different ages. The effects of including different models of the mating process, alternative mating strategies, and the possibility of developmental sex change (a known phenomenon in some groups of plants and animals) will be addressed. The results will have implications for the understanding and management of populations in which the interaction of males and females is an important determinant of population dynamics. They may also be applicable to human demographic analysis.
