Shifts from cooperative to individual-based predation defense determine microbial predator-prey dynamics

This research explores the dynamics of a microbial predator-prey system (bacterivorous flagellates *Poteriospumella lacustris* feeding on *Pseudomonas putida*) over five weeks. A consistent succession of bacterial defenses was observed across all replicates. Initially, a highly effective cooperative defense based on toxic metabolites nearly eliminated predators. However, this was superseded by an individual-based defense emerging through de novo mutations. Experiments and mathematical modeling demonstrate this shift is driven by maximizing individual, not population, benefits, highlighting the role of rapid evolution in breaking down social cooperation.

Magali de la Cruz Barron, Ellen van Velzen, Uli Klümper, Markus Weiter, Thomas U. Berendonk, David Kneis