Stabilization of Microbial Communities by Responsive Phenotypic Switching

TL;DR

This paper investigates how responsive phenotypic switching in microbes, influenced by environmental cues, can stabilize microbial communities and promote coexistence beyond stochastic switching effects.

Contribution

It demonstrates that responsive switching, driven by environmental factors, uniquely stabilizes microbial communities and extends classical stability results to include such mechanisms.

Findings

Responsive switching differs from stochastic switching in community stability.

Responsive switching can stabilize coexistence even when stochastic switching cannot.

Theoretical and numerical analysis extend classical competition stability results.

Abstract

Clonal microbes can switch between different phenotypes and recent theoretical work has shown that stochastic switching between these subpopulations can stabilize microbial communities. This phenotypic switching need not be stochastic, however, but could also be in response to environmental factors, both biotic and abiotic. Here, motivated by the bacterial persistence phenotype, we explore the ecological effects of such responsive switching by analyzing phenotypic switching in response to competing species. We show that the stability of microbial communities with responsive switching differs generically from that of communities with stochastic switching only. To understand the mechanisms by which responsive switching stabilizes coexistence, we go on to analyze simple two-species models. Combining exact results and numerical simulations, we extend the classical stability results for the competition of two species without phenotypic variation to the case in which one species switches, stochastically and responsively, between two phenotypes. In particular, we show that responsive switching can stabilize coexistence even when stochastic switching on its own does not affect the stability of the community.