Individual-based modelling of microbes

The approach of Individual-based modelling (IbM) is simple: to describe the behaviour of the individual organisms rather than describing the behaviour of a population of individuals directly, because the population level properties emerge from actions and interactions among individuals and with their environment (bottom-up approach). For example, fitness consequences of individual behaviour are emergent properties. While it seems natural to use IbM for birds and other 'macrobes', microbes have no brains and their behaviour should be much simpler as a consequence. Maybe surprisingly, bacteria do show social behaviour such as cooperation and communication and even isogenic individuals can differ drastically in status and behaviour - a key reason to use IbM - due to stochastic gene regulation and differences in their local environment and history. In fact, microbes are increasingly used as model systems for fundamental evolutionary and ecological problems. The talk will discuss some of the issues specific for IbM of microbes such as the tight coupling to physical processes like diffusion, by using an IbM of biofilms (spatially structured surface attached communities) as a paradigmatic example. Applying the model to the 'tragedy of the commons' problem, I will show how altruistic behaviour can evolve in biofilms.

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