All animals are colonized by microorganisms that play an important but poorly-understood role in sustaining the health and fitness of their animal host. The fruit fly Drosophila melanogaster and related drosophilid flies offer uniquely tractable systems to study how animals interact with their resident microbiota.
We have demonstrated that the microbiota in drosophilid flies is of low diversity, dominated by readily-culturable bacteria. Our experiments using axenic (germ-free) flies and flies bearing specific bacteria have revealed the pervasive effects of the microbiota on nutritional health. Certain bacterial species and bacterial communities promote host growth and development, protect the host against excessive lipid accumulation on high-sugar diets, and provide B vitamins important for host health on low-nutrient diets. Our current research is investigating the identity and metabolic traits of microorganisms that mediate these effects on host metabolism, recognizing that some effects may the product of among-microbe interactions, i.e. community metabolism.
In parallel, we are interrogating the microbiota in natural populations of Drosophila species and the relationship between the taxonomic diversity of the microorganisms and the functional traits of both the microbiota and the host. These analyses provide the mechanistic underpinning to understand how the microbiota influence ecologically-important traits of their insect hosts, including food choice, competitive interactions and susceptibility to pathogens and parasites.
Selected Recent Publications
Bost A, Franzenburg S, Adair KL, Martinson VG, Loeb G and Douglas AE, 2017. How gut transcriptional function of Drosophila melanogaster varies with the presence and composition of the gut microbiota. Molecular Ecology Epub Nov 7
Winans NJ, Walter A, Chouaia B, Chaston JC, Douglas AE and Newell PD, 2017. A genomic investigation of ecological differentiation between free-living and Drosophila-associated bacteria. Molecular Ecology, 26: 4536-4550.
Kim G-H, Huang J-H, McMullen JG, Newell PD and Douglas AE, 2017. Physiological responses of insects to microbial fermentation products: insights from the interactions between Drosophila and acetic acid. Journal of Insect Physiology Epub 15 May
Martinson VG, Douglas AE and Jaenike J, 2017. Community structure of gut microbiota within and among sympatric species of wild Drosophila. Ecology Letters 20: 629-39.
Dobson AD, Chaston JM and Douglas AE 2016. The Drosophila transcriptional network is structured by microbiota. BMC Genomics 17, 975.
Adair KL and Douglas AE 2016. Making a microbiome: The many determinants of host-associated microbial community composition. Current Opinion in Microbiology 35, 23-29.
For financial support of our research on Drosophila and its microbiome, we thank:
NSF BIO 1241099 Animal-microbial interactions as an engine of phylogenetic and functional diversity (with J. Jaenike and G. Loeb, current)