How do species adapt and survive in habitats with locally varying selection pressures and heterogeneous distribution of resources? Understanding this is essential, as most species live in spatially structured environments and their eco-evolutionary dynamics underpin ecosystems’ resilience, which in turn impacts the integrity of our food and health systems. However, addressing this question mathematically when considering sexually reproducing populations presents several challenges, because of the inherent non-linear and non-local nature of the transmission of traits. This is enhanced especially when the trait underlying adaptation arises from a complex genetic basis involving a large number of genes. In my talk, I will present a few PDE models from my PhD which provide some insights on this topic.