title: Stochastic assembly produces heterogeneous communities in the Caenorhabditis elegans intestine.
abstract: Host-associated bacterial communities vary extensively between individuals, but it can be very difficult to determine the sources of this heterogeneity. Here, we demonstrate that stochastic bacterial community assembly in the Caenorhabditis elegans intestine is sufficient to produce strong interworm heterogeneity in community composition. When worms are fed with two neutrally competing, fluorescently labeled bacterial strains, we observe stochastically driven bimodality in community composition, in which approximately half of the worms are dominated by each bacterial strain. A simple model incorporating stochastic colonization suggests that heterogeneity between worms is driven by the low rate at which bacteria successfully establish new intestinal colonies. We can increase this rate experimentally by feeding worms at high bacterial density; in these conditions, the bimodality disappears. These results demonstrate that demographic noise is a potentially important driver of diversity in bacterial community formation and suggest a role for C. elegans as a model system for ecology of host-associated communities.
authors.affiliation: Physics of Livings Systems, Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America.
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Vega
authors.affiliation: Physics of Livings Systems, Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America.
authors.forename: Jeff
authors.initials: J
authors.lastname: Gore
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000382:microbiology*; D015169:Colony Count, Microbial; D004926:Escherichia coli / Q000502:physiology*; D007422:Intestines / Q000382:microbiology*; D008954:Models, Biological; D013045:Species Specificity; D013269:Stochastic Processes