BRENDAN BOHANNAN: "Host-Mi­cro­bio­mes as Me­ta­com­mu­nities"

Background: Humans and other animals are chimeric creatures, covered inside and out withmicroorganisms. These microbes are collectively known as an individual’s ‘microbiome’,and variation in microbiome composition across individuals has been linked to variation inhost health and well-being.

There is growing evidence that dispersal among microbiomes isan important driver of this variation. To better understand how dispersal interacts with otherfactors to determine the composition of host-microbiomes, metacommunity theory hasrecently been applied to host-microbiomes. Metacommunity theory posits that the dynamicswithin any local group of interacting species (a community) are governed both by processesthat occur within the community and by the process of dispersal which links communitiestogether. The relative strengths of dispersal and within-community dynamics create differentpatterns of diversity and species composition across space and time.{reference: Miller et al. 2018 TREE}.

Summary: In my talk, I will present evidence for the hypothesis that host-microbiomes act asmetacommunities. I will then discuss examples of the ecological implications of thishypothesis. I will focus on the role of the environment external to hosts (the “matrix” inmetacommunity theory) as a mediator of dispersal, and how it can shape the ecological traitsof host-associated microorganisms. I will end with a discussion of the evolutionaryimplications of host-microbiomes as metacommunities, including recent theory regarding theconditions necessary for coevolution and how dispersal among host-microbiomes may allow“collective inheritance” of microbiome traits. {reference: Miller & Bohannan 2019 Frontiers in Ecology and Evolution}.