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Increasing growth rate slows adaptation when genotypes compete for diffusing resources

Fig 2

Competition localization increases with growth rate or the distances between colonies, and decreases with the resource diffusion constant.

A) Two simulation “maps” with the same founder cell geometry but different growth rates. Circle size is proportional to final biomass of colonies begun with a single founder cell in a spatial environment after resources have been exhausted. The lines designate the Voronoi polygons. The text above each simulation diagram shows ζ on top. On the bottom we show the growth rate (μ1) back-calculated from the scaled model’s ζ when the resource diffusion constant is similar to that of glucose in agar and the simulation area is 2.5cm X 2.5cm. B) A plot of relative biomass (biomass of a focal colony divided by the summed biomass of all colonies) versus relative polygon area (polygon area of a focal colony divided by the total simulation area) for the two simulations shown in A. Each point represents a different colony. The lines are linear least-squares fits, and the slope of each line is our measurement of competition localization. C) Competition localization versus ζ for two different founder densities. Each point is the mean competition localization for a given growth rate and founder density. Vertical error bars are standard deviation of 10 replicates each with different founder locations. Horizontal error bars are standard deviation of ζ due to different mean nearest-neighbor distances across maps (, see Materials and Methods).

Fig 2