Inhibitory interactions promote frequent bistability among competing bacteria

Area of Science:

• Microbiology
• Ecology
• Systems Biology

Background:

• Understanding microbial community assembly is crucial for ecology and biotechnology.
• Factors like species arrival order, abundance, and interactions significantly influence community structure.
• Invasibility networks offer a minimal framework to study frequency-dependent competition.

Purpose of the Study:

• To investigate how species arrival order, initial abundances, and interactions affect microbial community assembly.
• To construct and analyze an empirical invasibility network for microbial strains.
• To elucidate the role of antibiotic inhibition in microbial community dynamics.

Main Methods:

• Utilized a panel of prolific small-molecule producing microbial strains.
• Experimentation conducted in a habitat simulating feast-and-famine cycles.
• Constructed an empirical invasibility network based on strain interactions and abundance dynamics.

Main Results:

• The most abundant strain frequently excluded other strains, leading to bistability between strain pairs.
• The empirically determined invasibility network was characterized by multiple non-invadable strains, lacking cyclic dominance.
• Antibiotic inhibition played a dual role: aiding high-abundance producers in resisting invasion and hindering low-abundance producers.

Conclusions:

• Microbial community assembly is complex, with initial conditions and interactions shaping outcomes.
• Invasibility networks reveal stable coexistence patterns beyond simple competitive exclusion.
• Antibiotic production is a key mechanism driving bistability and influencing invasion dynamics in microbial communities.