Eco-evolutionary dynamics in discrete-time population models: insights from theoretical and experimental studies

This paper summarizes results obtained by the authors on models describing the relationship between ecological and microevolutionary processes in populations. The approach jointly considers population size dynamics as well as changes in genetic composition within the framework of discrete-time mathematical models, which naturally describe the dynamics of species with pronounced seasonal reproduction. Integrating these aspects of population biology allows the identification of effects that do not arise when demographic and genetic processes are studied separately. The analysis shows that incorporating population age structure and genetic heterogeneity substantially expands the range of possible dynamical modes. Such models can exhibit alternative stable states and transitions between different dynamical modes, as well as complex forms of temporal variability in both population abundance and genetic structure. These results help explain patterns of genetic differentiation among generations, fecundity polymorphism in certain populations, and changes in the character of population fluctuations—including the disappearance of cyclic dynamics—all observed in nature. Overall, the results demonstrate that the joint consideration of ecological and genetic dynamics produces qualitatively new effects and calls for a reconsideration of views based on the independent study of natural selection and density-dependent population regulation.