98th ESA Annual Meeting (August 4 -- 9, 2013)

August 03 - 09, 2013

OOS 9

Sex-Structured Population Dynamics: Theoretical and Empirical Approaches

As is well known, most theory in population dynamics considers only a single sex, usually females. This simplification is justified on the grounds that reproduction is seldom limited by the availability of males, and hence that a model in terms of female abundance will successfully capture the dynamics of the entire population. However, failures of this assumption are probably more common than realized. They may reflect different life histories of males and females, differential mortality, sex-specific interactions with mutualists or antagonists, and density effects, among other phenomena. Conservation biologists consider manipulations of the sex ratio to make reintroductions more successful, and managers of some kinds of insect pests use sterile male releases to interfere with mating as a way to make pests less successful. All of these circumstances suggest a need for two-sex models, which are different in important ways from other classes of models. In this session, the speakers will present recent work that addresses the effects that sex-structure (e.g., sex-ratios, mating systems, sex-bias in vital rates, etc.) can have on population dynamics. Talks will proceed from a consideration of the costs of having two sexes; to the mechanisms of the pair-formation process in two-sex models; to questions about the evolution of sex based differences in dispersal and skewed sex ratios; and to the implication of population sex structure for spread of biological invasions, conservation and management. The session will be structured to highlight recent theoretical advances in the ecology and evolution of sex-structured populations, and provide empirical case studies that connect two-sex theory to data.