Coevolution with a seed bank

Dormancy is as an adaptation to living in fluctuating environments. It can also influence species interactions, for example, by providing organisms with a refuge from predators and parasites. Here we test the hypothesis that dormancy generates a seed bank of protected individuals that can modify antagonistic coevolutionary dynamics. We experimentally evolved a spore-forming bacterial host along with a phage parasite that can infect active but not dormant cells. Seed banks buffered population dynamics against phage infection and retained phenotypic diversity that was otherwise lost to directional selection. By storing genetic diversity, seed banks also altered the distribution of host alleles, which contributed to dampened coevolutionary dynamics. Our findings demonstrate that dormancy generates a seed bank that can modify the eco-evolutionary outcomes of host-parasite systems.