Housefly (Musca domestica L.) associated microbiota changes continuously throughout the host life cycle

The common housefly (Musca domestica L.) is primarily known for its potential role as a vector of pathogens and as an epidemiological model organism, but only limited knowledge is available about its associated microbiota. The housefly undergoes profound physiological changes during development and in transformation from larvae to pupa to adult, including histolysis of the gut. How this transformation affects the microbiota composition and their metabolic capabilities is currently unknown. The present study applies 16S rRNA gene amplicon sequencing across two generations of houseflies to investigate the evolution of the host-associated microbiota during all stages of housefly life. Specifically, detailed attention was paid to the potential for microbiota transfer between life stages, generations and environment, as well as the metabolic potential of the microbiota during different stages of development. Representatives of Firmicutes were observed as early colonisers during the larval stages, followed by diverse colonisation by organisms from Proteobacteria and Bacteroidetes as the flies matured into adults. A near cyclic development of microbial diversity was observed between first and second sampled generation. Metabolic profiling of the identified microorganisms further suggested that the microbiota mature alongside their host and putative host-microbe relationships are established at different stages of development.