Growth and dynamics of active nematic droplets of <i>Myxococcus xanthus</i> bacteria

Myxococcus xanthus is a rod-shaped soil bacterium that exhibits various forms of emergent collective phenomena using only short-range interactions. When starved, they collectively bead from surfaces to form 3D droplet-like aggregates known as fruiting bodies that are comprised of hundreds of thousands of cells and are crucial for sporulation and survival. The combination of active cellular motility and local nematic interactions generates increased pressures that drive the dewetting process. Unlike passive fluids that form axisymmetric spherical cap-shaped droplets, we find that these aggregates break symmetry and are often elongated in shape with non-uniform contact angles. We characterize the growth and dynamics of these active nematic droplets and make progress towards understanding the role of motility in the formation of stable fruiting bodies through tracking sparsely labelled cells.