View Program - 2022 Population, Evolutionary, and Quantitative Genetics Conference

In a microbial biofilm, cells form into an aggregate, producing community goods and providing a variety of benefits to member cells. Cells in a biofilm must solve a coordination problem, in that key nutrients can become locally scarce depending on the feeding behavior of nearby cells. One way Bacillus subtilis biofilms solve this problem is through electrical signaling that regulates feeding. At the individual level, signaling is costly, but a network of signallers that can traverse the biofilm is important for biofilm survival. In this work, we consider signaling from a social evolution perspective, building on previous findings that the proportion of signallers in biofilms seems to hover near a quantity that can be predicted with percolation theory. Here, we extend previous work by considering the direction of biofilm growth and signaling. Individual B. subtilis cells have a long and a short axis, and the biofilms grow in rows, such that there is high relatedness along one axis and low relatedness on the other. Using theory and simulations, we explore how this structure may increase the efficacy of signaling and the resilience of the system to cheater cells.

An agent-based model of signaling in Bacillus subtilis biofilms