Bacillus subtilis swarms rapidly over the surface of a synthetic mediumcreating remarkable hyperbranched dendritic communities. Models to reproduce such effectshave been proposed under the form of parabolic Partial Differential Equations representingthe dynamics of the active cells (both motile and multiplying), the passive cells(non-motile and non-growing) and nutrient concentration. We test the numerical behavior ofsuch models and compare them to relevant experimental data together with a criticalanalysis of the validity of the models based on recent observations of the swarmingbacteria which show that nutrients are not limitating but distinct subpopulations growingat different rates are likely present.
