Fig. 5

Moderate levels of migration help populations survive longer in harsh environments. a Simulated probability distributions of survival times of populations in a harsh environment (10 μg/ml of ampicillin, 16 μg/ml of chloramphenicol) for various migration rates. The distributions were generated from 6000 simulation runs with initial conditions distributed around the three phases of the period-3 oscillations observed in Fig. 4c. Connected patches were initialized in different phases to avoid minimize synchronization. P(τ) is defined as the fraction of initial conditions that survived for τ days. Different colors represent different migration rates, as indicated in the colorbar. The survival time distributions have longer tails at intermediate migration rates. The black vertical line indicates the threshold (10 days) used for calculating the survival probability. This threshold was chosen to match the duration of the experiments. b Simulated probability of survival after 10 days in the harsh environment as a function of the migration rate. c Experimentally measured survival probability after 10 days as a function of the migration rate from 18 replicate pairs (3 biological replicates × 6 technical replicates) of co-cultures. Both b and c exhibit a maximum at intermediate migration rates, demonstrating that moderate amounts of migration help populations to survive longer in harsh environments. The error bars in b and c are standard errors of proportion