title: Evolutionary ecology of microbial wars: within-host competition and (incidental) virulence.
abstract: Invading an occupied niche is a formidable ecological challenge, and one of particular human importance in the context of food-borne microbial pathogens. We discuss distinct categories of invader-triggered environmental change that facilitate invasion by emptying their niche of competitors. Evidence is reviewed that gut bacteria use such strategies to manipulate their environment (via bacteriocins, temperate phage viruses or immuno-manipulation) at the expense of their competitors are reviewed. The possible virulence implications of microbial warfare among multiple co-infecting strains are diverse. Killing competitors can reduce virulence by reducing overall microbial densities, or increase virulence if for example the allelopathic mechanism involves immuno-manipulation. Finally, we place microbial anti-competitor strategies in a social evolution framework, highlighting how costly anti-competitor strategies can be understood as examples of microbial spite. We conclude by discussing other invasive species that have also developed such proactive strategies of invasion.
authors.affiliation: Department of Zoology, University of Oxford South Parks Road, Oxford, UK.
authors.forename: Sam P
authors.initials: SP
authors.lastname: Brown
authors.affiliation: Department of Zoology, University of Oxford South Parks Road, Oxford, UK.
authors.forename: R
authors.initials: R
authors.lastname: Fredrik Inglis
authors.affiliation: University of Paris, Faculty of Medicine INSERM, U571, Paris, France.
authors.forename: François
authors.initials: F
authors.lastname: Taddei
keywords: disease biology; evolutionary theory; microbial biology; social evolution; virulence