Movie S4.

A graphical illustration of the sensitivity of the bacterial dynamics in the age-structured spatially implicit model, discussed in Results and Discussion and in SI Appendix, 2.2 Spatially Implicit Model, to varying the three free parameters in the model. The experimentally measured time to collapse of the bacterial population on the R= 2-cm plate, t= 144 h, is plotted as the vertical dashed black line. The parameter c, the saturation rate of the Holling’s type II functional response (SI Appendix, Eq. S.3), is varied over a 15-fold increase, from c= 5×10−10 to c= 7.5×10−9 cells−1. The parameter σ, which controls how the worms’ foraging efficiency changes with plate size (SI Appendix, Eq. S.4), is varied over a 20-fold increase, from σ= 100 to σ= 2,000 cm2. The parameter s, the rate at which bacteria is spread by farmers (SI Appendix, Eq. S.5), is varied over a 300-fold increase, from s= 7×10−11 to s= 2.1×10−8 min−1cm−2.