Microbiota-by-environment interactions in Drosophila melanogaster development

Insects are the most diverse group of organisms, filling many different niches. However, insects rarely crawl alone, their evolutionary success is linked to associated microbes, known as microbiota. Microbiota are involved in the metabolism of complex nutrients, but also play a role in detoxification and as defensive symbionts. While some insects receive microbiota from conspecifics, often the parents, others establish microbiota from the environment. The fruit fly Drosophila melanogaster exhibits ecological intermediacy. Adult flies frequently replenish microbiota through ingestion, but offspring are supplied with fecal microbiota, that coat the eggs. Larval development depends on the microbiota in combination with the surrounding substrate. Since D. melanogaster is a fruit generalist in terms of its reproductive niche, a mismatch between the environmental microbiota and the new environment can have negative effects on larval development. We replicated this event in the laboratory to record developmental phenotype, diet and microbiota composition. We find that fruit flies ensure larval development in microbiota-environment mismatched breeding sites through dietary flexibility.