Meeting Abstract
The gut of insects is host to bacteria, archaea, fungi, protozoans and viruses, and together they affect host physiology. Most studies have focused on the bacterial microbiota, but little is known about the other members of the gut flora. The gut microbiota of Drosophila melanogaster is relatively simple, and its bacteria and yeast species have been characterized, thus making it a useful system for understanding the role of yeasts in insect physiology. Yeasts are usually regarded as a food source; however, here we show that the effect of yeasts on D. melanogaster development is not solely explained by the nutritional content of the yeast. To investigate the effect of yeast on Drosophila development time, we started by rearing the flies either as axenic (free of microbes), or gnotobiotic (with a known yeast species in their gut), and recorded the pupation and eclosion times. We used two species of yeast, Saccharomyces cerevisiae, which is commonly used in lab settings and Lachancea kluyveri, which can be recovered from the gut of some wild caught Drosophila species. Both yeasts reduce development time equally, and the biggest effect is observed when the yeast is alive (gnotobiotic flies). While heat-killed yeast and nutritional supplements reduce the development time in axenic flies, they do not replicate the effect of live yeasts.
