Endosymbiont and Gut Bacterial Communities of the Brown-banded Cockroach,

The brown-banded cockroach () is a widespread nuisance and public health pest. Like the German cockroach (), this species is adapted to the indoor biome and completes the entirety of its life cycle in human-built structures. Recently, understanding the contributions of commensal and symbiotic microbes to the biology of cockroach pests, as well as the applications of targeting these microbes for pest control, have garnered significant scientific interest. However, relative to , the biology of , including its microbial associations, is understudied. Therefore, the goal of the present study was to quantitatively examine and characterize both the endosymbiont and gut bacterial communities of for the first time. To do so, bacterial 16S rRNA gene amplicon sequencing was conducted on DNA extracts from whole adult females and males, early instar nymphs, and late instar nymphs. The results demonstrate that the gut microbiome is dominated by two genera of bacteria known to have beneficial probiotic effects in other organisms, namely and . Furthermore, our data show a significant effect of nymphal development on diversity and variation in the gut microbiome. Lastly, we reveal significant negative correlations between the two intracellular endosymbionts, and , as well as between and the gut microbiome, suggesting that endosymbionts could directly or indirectly influence the composition of other bacterial populations. These findings have implications for understanding the adaptation of to the indoor biome, its divergence from other indoor cockroach pest species such as , the development of novel control approaches that target the microbiome, and fundamental insect-microbe interactions more broadly.