Because insect immune responses are known to vary by age and developmental stage \cite{25730277,18001766,20932328}, we sought to determine if there were any differences in susceptibility to F. tularensis LVS in juvenile and adult cockroaches. Injections in adults were performed using the same method described for the juveniles. Cockroaches cannot be separated by gender as juveniles, but anatomical differences (Figure 1C) make gender determination possible in adults. We, therefore, analyzed survival in adult female and adult male cockroaches separately. We found that although the overall percentages of surviving cockroaches differed slightly between adult female (50 percent survival) and juvenile (30 percent survival) cockroaches, both groups were equally susceptible to F. tularensis LVS infections (juvenile mean time-to-death 4.7 days; adult female mean time-to-death 4.8 days; no statistical difference between groups). By comparison, adult male cockroaches were more sensitive to killing by F. tularensis LVS, with rapid death rates (mean time-to-death 3.8 days) and 100% mortality by day 6 post-infection (p=0.0169 compared with juveniles; p<0.001 compared with adult females; Figure 5). The LD_50 of adult males was determined to be 1.3 x 10^3 CFU, which is a 1.4- and 1.6-log decrease from that of juvenile and adult female cockroaches, respectively (Table 1).