Fig. 4: Retention of susceptible hosts with a seed bank.

We quantified susceptibility by challenging clones of Bacillus subtilis against the ancestral phage. In both the + seed bank and - seed bank treatments, we performed this assay on clones (n = 22) that were isolated from each focal population contained in a flask (Fig. 1) just prior to serial transfer (). In addition, we revived clones (n = 22) from the external seed bank (Fig. 1) at each time point and challenged those against the ancestral phage (). The expected percentage of susceptible clones () is based on losses to dilution caused by serial transfer of clones originating from the pre-infection external seed bank (see Supplementary Information). Data represented as mean ± SEM of the replicate populations (n = 3).