Abstract
Over the last decade, many studies have demonstrated that the gut microbiota strongly affects essential traits associated with fitness, such as immunity or growth. For example, axenic Drosophila larvae (without any microbiota) cannot develop and die at an early developmental stage. Studies has also shown that the gut microbial community is shaped by the host. However, the relative role of the host life stage, fruit substrate, and host genotype on the composition of the bacterial and fungal gut communities has been less studied. Here we study how these three factors affect the bacterial and yeast communities composition of Drosophila suzukii, an exotic invasive fruit pest that infests multiple host plants. To test for the potential effects of the host life stage, fruit substrate and host genotype on the gut bacterial and yeast communities of D. suzukii, we used a metabarcoding approach by sequencing 16S and ITS markers. We artificially infested fresh fruits (strawberry, cherry and blackberry) with lab-reared flies (two different genotypes). We extracted larvae from host fruits and transfer them to a pasteurized medium until they pupate. We sampled individuals at each developmental stages (larva, pupa, adult) and fruits before and after infestation. Our first results indicate that the yeast community is strongly structured among life stages (i.e. larvae, pupae, adults) and among fruit varieties (i.e. strawberry, cherry, blackberry), but not among host genotypes. On the contrary, the bacterial community is shaped mostly by life stages. These preliminary results indicate that metamorphosis plays a crucial role in shaping the gut microbial community. We will discuss how different transmission patterns between bacteria and yeast communities may affect the fitness of insect hosts.