Figure 4: Coefficient of variation of both subpopulations increases as the environment deteriorates due to increasing dilution factor.

The coefficient of variation (CV) measured for both producer (green) and freeloader (red) populations as a function of dilution factor. Populations were grown from the same initial density of producers and freeloaders, and the coefficient of variation across the 20 replicates for each dilution factor was measured on the final day of the experiment (day 9). Inset figures represent the time series of the producer density (measured in 10⁶ cells ml⁻¹) of each replicate at a low dilution factor (left panel) and a high dilution factor (right panel). Similar results were found for the freeloader populations. Error bars are standard errors obtained by bootstrapping with 100 resamplings.