In nature, bacterial collectives typically consist of multiple species, which are interacting both biochemically and physically. Nonetheless, past studies on the physical properties of swarming bacteria were focused on axenic (single-species) populations. In bacterial swarming, intricate interactions between the individuals lead to clusters, rapid jets, and vortices that depend on cell characteristics such as speed and length. In this work, we show the first results of rapidly swarming mixed-species populations of Bacillus subtilis and Serratia marcescens, two model swarm species that are known to swarm well in axenic situations. In mixed liquid cultures, both species have higher reproduction rates. We show that the mixed population swarms together well and that the fraction between the species determines all dynamical scales - from the microscopic (e.g., speed distribution), mesoscopic (vortex size), and macroscopic (colony structure and size). Understanding mixed-species swarms is essential for a comprehensive understanding of the bacterial swarming phenomenon and its biological and evolutionary implications.
|Journal||Physical Review E|
|State||Published - Jun 2022|
Bibliographical noteFunding Information:
We thank Rasika M. Harshey and Daniel B. Kearns for sending the strains and Avigdor Eldar for creating the fluorescent variants. We thank Zeev Ronen for useful discussions. Partial support from the Deutsche Forschungsgemeinschaft (German Research Foundation) Grants No. HE5995/3-1 and No. BA1222/7-1 is thankfully acknowledged.
© 2022 American Physical Society.