PLoS Biol. 6, e2005710 (2018).
The microbes that live in the Drosophila gut are known to influence aspects of its physiology, but the relationship was thought to be transitory—the bacteria had to be constantly re-ingested. But a new study suggests there might be some stable symbionts after all.
The researchers first tested for overall community stability in lab-reared and wild-caught flies. Flies spent either 10 days with the same food source (to encourage re-ingestion of bacteria) or were transferred twice per day to clean vials with fresh food (to avoid it). Lab flies needed re-ingestion to maintain the overall concentration of gut bacteria, but wild flies…not so much. But the composition of that wild community in the latter protocol was in flux. By Day 10, the wild fly’s bacterial diversity was reduced to just a few species, which could then stably exist in germ-free lab flies too.