Fig. 4: Importance of disentangling factors driving pattern formation.

Pattern formation of two cross-feeding amino acid auxotrophic strains, simulated using the gro toolbox¹⁵⁴. One of the two strains is non-motile (blue), while the other is motile (orange) with motility increasing with amino acid concentration. The interaction strength is tuned by setting the amino acid concentrations in the media, with higher concentrations reducing the metabolic dependency between the two strains. In the simulations, each microcolony is initialized by two cells from each type. a The amino acid concentration in the media influences intermixing non-monotonically. To better understand the pattern formation in this mixed colony, we consider the self-patterns formed by each strain individually in varying media compositions. These can be visualized using differential color labeling where half the founder cells of each species are colored in gray. b Amino acid concentrations do not substantially affect the patterns for the blue species. c Amino acid concentrations increase intermixing in the orange species as its motility increases at higher amino acid concentrations. The parameters used in the simulations are listed in Supplementary Note 1.