How Nested Infection Networks in Host-Phage Communities Come To Be

TL;DR

This paper demonstrates conditions under which nested bacteria-phage infection networks in a chemostat community are permanent and shows how such networks can develop through successive stable subcommunities.

Contribution

It establishes sufficient conditions for the permanence of nested infection networks and describes a process for their emergence via community succession.

Findings

Nested infection networks are permanent under specific competitive and infectivity conditions.

A nested bacteria-phage community can develop through successive stable subcommunities.

Provides theoretical framework confirming earlier hypotheses on network permanence.

Abstract

We show that a chemostat community of bacteria and bacteriophage in which bacteria compete for a single nutrient and for which the bipartite infection network is perfectly nested is permanent, a.k.a. uniformly persistent, provided that bacteria that are superior competitors for nutrient devote the least to defence against infection and the virus that are the most efficient at infecting host have the smallest host range. This confirms earlier work of Jover et al \cite{Jover} who raised the issue of whether nested infection networks are permanent. In addition, we provide sufficient conditions that a bacteria-phage community of arbitrary size with nested infection network can arise through a succession of permanent subcommunties each with a nested infection network by the successive addition of one new population.