Chapter 9 - Role of the Microbiota During Development of the Arthropod Vector Immune System

Abstract

Arthropod disease vectors and the bacterial microbes they carry exhibit varying levels of coevolutionary integration, and these associations reflect distinct host–microbe physiological codependences. The mosquito microbiota, which is largely transient and environmentally acquired during larval and adult stages, facilitates host maturation and modulates vector competency during adulthood. Unlike mosquitoes, tsetse flies are obligate blood feeders and thus house a steadfast population of vertically transmitted obligate, commensal, and parasitic bacterial symbionts. Tsetse that undergo development in the absence of their indigenous microbiota are severely immunocompromised during adulthood. Specifically, these “aposymbiotic” flies lack a functional cellular immune system and fail to produce a structurally robust peritrophic matrix midgut barrier. Thus, aposymbiotic tsetse adults are unusually susceptible to systemic infection with normally nonpathogenic Escherichia coli and midgut infection with parasitic trypanosomes. Further studies related to deciphering molecular mechanisms that underlie microbiota-modulated maturation of the arthropod disease vector immune system can lead to the development of novel pathogen transmission blocking control strategies.