Berlin 2012 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 5: Statistical Physics of Biological Systems II (with DY)

BP 5.2: Vortrag

Montag, 26. März 2012, 15:15–15:30, H 1058

Evolution of cooperation in microbial biofilms - A stochastic model for the growth and survival of bacterial mats — •Johannes Knebel, Anna Melbinger, Jonas Cremer, and Erwin Frey — LMU Muenchen, Deutschland

Cooperating microbes are widespread in nature despite running the risk of being exploited by free-riders. This so-called dilemma of cooperation is especially important for microbial biofilms where diverse different strains interact in a complex community. The structure and composition of such a biofilm change over time and thereby influence the evolution of cooperation within the system. In turn, the level of cooperation affects the growth dynamics of the biofilm.

Here, we investigate this coupling for an experimentally well-defined situation in which mutants of the Pseudomonas fluorescens strain form a mat at the liquid-air interface by the production of an extra-cellular matrix [1]. We model the occurrence of cooperation in this bacterial population by taking into account the formation of the mat. The presence of cooperators enhances the growth of the mat, but at the same time cheaters can infiltrate the population and put the viability of the mat at risk. We find that the survival time of the mat crucially depends on its initial dynamics which is subject to demographic fluctuations [2]. More generally, our work provides conceptual insights into the requirements and mechanisms for the evolution of cooperation.

[1] P. Rainey et al., Nature 425, 72 (2003).

[2] A. Melbinger et al., PRL 105, 178101 (2010).