Mating, births, and transitions: a flexible two-sex matrix model for evolutionary demography

Area of Science:

• Population Dynamics
• Mathematical Biology
• Evolutionary Ecology

Background:

• Single-sex demographic models fail to account for sex-specific differences in demographics and mate availability.
• Understanding the interplay between sex-specific traits and population dynamics is crucial for accurate ecological and evolutionary modeling.

Purpose of the Study:

• To develop a novel mathematical framework for two-sex demographic models.
• To extend the birth-matrix mating-rule approach for incorporating complex mating dynamics.
• To analyze the impact of mating strategies and sex-biased harvesting on population dynamics and evolution.

Main Methods:

• Developed a continuous-time matrix model incorporating nonlinear mating, offspring production, and demographic transitions.
• The model allows for age- or stage-structured life histories and flexible mating functions.
• Applied the model to investigate sex-biased harvesting effects under various mating strategies (monogamy, polygamy).

Main Results:

• The nonlinear model converges to exponential population growth with a stable equilibrium composition.
• Mating strategies significantly influence population responses to sex-biased harvesting.
• Demographic complexity and inter-sexual interactions can alter evolutionary trajectories of sex-related traits.

Conclusions:

• The presented two-sex demographic model provides a robust framework for studying complex population dynamics.
• Incorporating sex-specific factors and mating behaviors is essential for predicting population persistence and evolutionary outcomes.
• This approach offers new insights into the evolutionary consequences of ecological pressures on sexually reproducing populations.