Functional roles of the gut microbiome of the German cockroach

The German cockroach, Blattella germanica, is a major indoor pest of health concern that harbors a highly complex gut microbiome that includes numerous bacterial taxa as well as fungi, archaea, and protozoa. The gut microbiome is acquired from the environment, as the only vertically transmitted constituent is the fat body endosymbiont, Blattabacterium, and the specific composition can vary drastically based on where the insects mature in the field. Major functional roles for the microbiome, which will be discussed in this presentation, include regulation of behavior, development, insecticide resistance, and protection against infection with human pathogens. Experiments involving the use of gnotobiotic individuals which lack an intact gut microbiome have shown severe developmental delay, underlining the importance of the commensal community for optimal growth and development. Furthermore, individuals experiencing dysbiosis are more susceptible to some insecticides and to colonization by foreign human enteropathogenic bacteria such as E. coli and Salmonella Typhimurium. These findings emphasize the need for more research into the complex interactions between the German cockroach and its gut microbiota while also highlighting the potential promise of targeting the gut microbiome to improve control of cockroaches and their associated adverse effects on health.