14 Swarming in Pseudomonas aeruginosa is a quorum-dependant motility over semi-solid 15 surfaces. On soft agar, P. aeruginosa exhibits a dendritic swarm pattern, with multiple levels 16 of branching. Swarm patterns vary considerably depending upon the experimental design. In 17 the present study, we show that the swarm pattern is plastic and media dependent. We define 18 several quantifiable, macroscale features of the swarm to study the plasticity observed across 19 media. Further, through a targeted screen of 113 genes encoding two-component system 20 (TCS) components, we show that 44 TCS genes regulate PA14 swarming in a contextual 21 fashion. However, only four TCS genes are essential for swarming. Many swarming-defective 22 TCS mutants are highly efficient in biofilm formation indicating an antagonistic relationship 23 between swarming and biofilm states in P. aeruginosa. 24 25