Diverse modes of eco-evolutionary dynamics in communities of antibiotic-producing microorganisms

Whether and how toxin-mediated interactions contribute to diversity generation and maintenance has been a long-standing puzzle. A recent theoretical work has demonstrated that the interplay between antibiotic production and degradation can robustly maintain coexistence of several microbial strains with different antibiotic production and resistance capabilities. The questions, however, remain whether evolution can spontaneously arrive at such communities and whether this mechanism works when biologically realistic features are incorporated. Here I perform multi-scale eco-evolutionary simulations, in which microorganisms compete for a single resource in a two-dimensional environment and evolve their investment in reproduction, antibiotic production and degradation with respect to multiple antibiotics. I show that the dynamics can readily reach long-persistent diverse communities belonging to three different eco-evolutionary classes. First, the dynamics could settle into evolutionary stable states, which were in fact more diverse than those predicted by minimal models. Second, the eco-evolutionary dynamics could exhibit intermittency with prolonged periods of apparent community stability. Finally, communities could persist despite being ecologically unstable through stabilizing loss-of-function mutations. These findings demonstrate that the interplay between toxin production and degradation is a viable mechanism for explaining diversity, and they expand our understanding of the different possible types of eco-evolutionary dynamics in microbial communities.