Autotransduction frequencies recorded over time during co-infection of G. mellonella larvae with 8325-SR and (a) 8325-4 SaPI or (b) USA300. At each time point, 20 larvae were sampled and total CFU and triple-resistant colonies were determined from the haemolymph. The calculated autotransduction frequencies are shown for the larvae in which autotransduction was observed. Filled and open symbols represent living and dead larvae, respectively. No autotransduction was observed in the inoculum used for infection; when lysogenic bacteria were substituted with a phage-cured derivative (JH978); when the non-lysogenic strain was substituted with 8325-4 not carrying an antibiotic resistance marker or when larvae were injected with a PBS control (detection limit=2e−9).