Digest: Natural selection fluctuates at an extremely fine spatial scale inside a wild population of snapdragon plants.

Marrot et al. used snapdragon plants on a small island to experimentally investigate how spatial structure influences the evolution of biological communities. Using a spline-based fitness function, they studied the varying relationships between traits under selection and driving environmental factors in snapdragons. The authors found that environmental heterogeneity, even on a small spatial scale, may provide several fitness optima on the fitness landscape, paving the way for coexistence of diverse phenotypes. In the absence of sufficient gene flow, this could also lead to microgeographic adaptations.