title: Computation of mutual fitness by competing bacteria.
abstract: Competing populations in shared spaces with nonrenewable resources do not necessarily wage a battle for dominance at the cost of extinction of the less-fit strain if there are fitness advantages to the presence of the other strain. We report on the use of nanofabricated habitat landscapes to study the population dynamics of competing wild type and a growth advantage in stationary phase (GASP) mutant strains of Escherichia coli in a sealed and heterogeneous nutrient environment. Although GASP mutants are competitors with wild-type bacteria, we find that the 2 strains cooperate to maximize fitness (long-term total productivity) via spatial segregation: despite their very close genomic kinship, wild-type populations associate with wild-type populations and GASP populations with GASP populations. Thus, wild-type and GASP strains avoid each other locally, yet fitness is enhanced for both strains globally. This computation of fitness enhancement emerges from the local interaction among cells but maximizes global densities. At present we do not understand how fluctuations in both spatial and temporal dimensions lead to the emergent computation and how multilevel aggregates produce this collective adaptation.
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands. j.e.keymervergara@tudelft.nl
authors.forename: Juan E
authors.initials: JE
authors.lastname: Keymer
authors.forename: Peter
authors.initials: P
authors.lastname: Galajda
authors.forename: Guillaume
authors.initials: G
authors.lastname: Lambert
authors.forename: David
authors.initials: D
authors.lastname: Liao
authors.forename: Robert H
authors.initials: RH
authors.lastname: Austin
mesh_terms: D000222:Adaptation, Physiological; D002450:Cell Communication; D017753:Ecosystem; D004926:Escherichia coli / Q000502:physiology*; D011157:Population Dynamics; D013045:Species Specificity