Pattern Formation and Emergence of Collective Behavior in Bacterial Growth

Collective surface migration of bacterial cells on a growth medium can lead to interesting spatiotemporal patterns and dynamical behaviors. Studying the rich behavior of these swarming colonies can provide insight in how the multicellular organisms were originally formed. Bacterial swarming is an example of emergent behavior as a result of interplay between the collective interactions of a population of bacterial cells, colony growth, and hydrodynamic motions. Several models have been proposed to describe bacterial swarming some of which can qualitatively reproduce a variety of colony shapes observed in experiments. In this paper, some experimental work along with a theoretical model for the mechanism of pattern formation in bacterial swarming that captures some qualitative and quantitative aspects of this phenomenon is reviewed.