FIG. 2.

Effects of different rearing regimens on rates of mortality of third-instar M. sexta larvae exposed to B. thuringiensis HD73 Cry⁻ spores and an otherwise sublethal Cry1Ac concentration. ▪, nonsterile without antibiotic exposure; ○, aseptic with antibiotic exposure during the first instar only; •, aseptic with continuous antibiotic exposure prior to bioassay. Error bars indicate 95% confidence intervals of the means of data from two repetitions. Results for Cry1Ac alone (□) and for B. thuringiensis HD73 Cry⁻ spores alone (▾) were combined, as there were no significant differences in mortality rates between larvae from all three rearing regimens.