Speciation through sexual selection in spatially heterogeneous environments
Speciation in sympatry has received considerable attention because, unlike speciation in allopatry, the lack of population subdivision means that reproductive isolation must be achieved in the presence of persistent gene flow. One mechanism that is thought to be capable of creating reproductive isolation in sympatry is frequency-dependent disruptive selection, i.e., selection against intermediate phenotypes resulting from the frequency-dependent interactions between individuals. The focus of this research project will be to investigate how frequency-dependent mobility, mortality, and fecundity – mechanisms that may induce the spatial self-structuring of populations – influence the long-term evolution of assortative mating in heterogeneous environments and thus potentially lead to adaptive speciation through sexual selection. For this purpose, we will develop and investigate both stochastic individual-based models and deterministic analytical models. We will start by reproducing results already present in the literature, before extending the underlying models to allow for more complex heterogeneous environments. In this manner we hope to achieve a more comprehensive understanding of the relative importance of environmentally imposed and dynamically generated spatial heterogeneity for the emergence and stable persistence of reproductively isolated populations.