Eco-evolutionary feedbacks can rescue cooperation in microbial populations.

Area of Science:

• Microbial Ecology
• Evolutionary Biology
• Systems Biology

Background:

• Cooperative bacterial populations producing public goods are vulnerable to invasion by non-contributing 'cheaters'.
• Maintaining cooperation often focuses on preventing cheater invasion, overlooking potential benefits of invasion.
• The interplay between ecological factors and evolutionary dynamics in microbial communities remains an active area of research.

Purpose of the Study:

• To investigate the unexplored prospect of cheater invasions leading to the persistence of cooperation.
• To demonstrate how ecological factors can influence evolutionary outcomes in microbial systems.
• To explore the mechanisms by which cooperation can be rescued despite the presence of cheaters.

Main Methods:

• Theoretical modeling of bacterial population dynamics.
• Experimental validation using a synthetic bacterial community.
• Engineering a system where a public good is essential for survival under lethal stress.
• Characterization of experimental systems, including lag phase effects and spontaneous mutations.

Main Results:

• Cheater invasion can induce demographic collapse, which paradoxically rescues cooperation.
• Spatial constraints and the essentiality of the shared resource are key factors enabling cooperation rescue.
• Experimental results confirmed theoretical predictions, showcasing eco-evolutionary feedbacks.
• Identified additional factors like lag phase duration and spontaneous mutants influencing community dynamics.

Conclusions:

• Eco-evolutionary feedbacks can generate unanticipated dynamics in microbial communities.
• Demographic collapse induced by cheaters can be a mechanism for rescuing cooperation.
• Understanding these feedbacks is fundamental for the adaptive change of ecosystems at all scales.
• The study highlights the intricate relationship between ecology and evolution in shaping microbial communities.