Swarming motility

This multicellular behavior has been mostly observed in controlled laboratory conditions and relies on two critical elements: 1) the nutrient composition and 2) viscosity of culture medium (i.e. % agar). One particular feature of this type of motility is the formation of dendritic fractal-like patterns formed by migrating swarms moving away from an initial location. Although the majority of species can produce tendrils when swarming, some species like Proteus mirabilis do form concentric circles motif instead of dendritic patterns.

Biosurfactant, quorum sensing and swarming

In some species, swarming motility requires the self-production of biosurfactant to occur. Biosurfactant synthesis is usually under the control of an intercellular communication system called quorum sensing. Biosurfactant molecules are thought to act by lowering surface tension, thus permitting bacteria to move across a surface.