Density-dependent feedback and higher-order interactions enable coexistence in phage-bacteria community dynamics.

Area of Science:

• Microbiology
• Ecology
• Systems Biology

Background:

• Phage-bacteria communities are vital in various ecosystems.
• Coexistence is often explained by pairwise coevolutionary dynamics.
• Higher-order interactions remain understudied as a stabilization mechanism.

Purpose of the Study:

• To investigate the role of higher-order interactions in stabilizing phage-bacteria communities.
• To explore how these interactions affect community dynamics beyond pairwise models.
• To determine if phage-bacteria coexistence is more common than previously thought.

Main Methods:

• In vitro experiments with a synthetic marine phage-bacteria community (5 bacteria, 5 phages).
• Bayesian inference for reconstructing phage production.
• Mathematical modeling to forecast community dynamics.
• Experimental validation of infection attenuation at high viral densities.

Main Results:

• All bacterial strains persisted in the community, contrary to pairwise model predictions.
• Higher-order interactions were identified as an ecological stabilization mechanism.
• Phage traits, like burst size, varied depending on whether they infected single or multiple bacterial strains.
• Community-level trait inference differed from pairwise inference, highlighting the impact of complex interactions.

Conclusions:

• Higher-order interactions are crucial for stabilizing phage-bacteria communities.
• Ecological feedback mechanisms beyond pairwise interactions promote complex coexistence.
• Current pairwise models may underestimate the stability and prevalence of phage-bacteria communities in nature.