The impact of symbiotic population crash (or reduction) on microbiome structure and composition

To examine how the sterilization techniques affect the structure, composition and diversity of gut bacterial communities, we used antibiotics and eggs disinfection approaches to generate aposymbiotic and axenic flies, respectively. Fruit flies often bear complex communities which are greatly reduced by such treatments. Here, we examine the effect of these procedures on the structure of the remaining bacterial communities of Bactrocera dorsalis. The antibiotics (Norfloxacin and Ceftazedime) were administered to 1 day old adult flies through sugar meal for seven days, and eggs were surface sterilized and dechorionated to produce axenic lines. The flies were starved from protein before they were offered full diets for their maintenance. Antibiotic treatments and eggs disinfection resulted in significant reduction of the vast majority of gut bacteria, especially Proteobacteria, Firmicutes and Bacteroidetes. However, Actinobacteria, Cyanobacteria and Acidobacteria which were in minority in symbiotic flies increased in size after treatments. These results suggest that alterations of gut bacteria through the sterilization techniques used here are suitable for generating aposymbiotic and axenic flies for functional study of gut bacteria in fruit fly.