title: Resource abundance and the critical transition to cooperation.
abstract: Cooperation is abundant in nature, occurring at all levels of biological complexity. Yet cooperation is continually threatened by subversion from noncooperating cheaters. Previous studies have shown that cooperation can nevertheless be maintained when the benefits that cooperation provides to relatives outweigh the associated costs. These fitness costs and benefits are not fixed properties, but can be affected by the environment in which populations reside. Here, we describe how one environmental factor, resource abundance, decisively affects the evolution of cooperative public goods production in two independent evolving systems. In the Avida digital evolution platform, populations evolved in environments with different levels of a required resource, whereas populations of Vibrio cholerae evolved in the presence of different nutrient concentrations. In both systems, cooperators and cheaters co-existed stably in resource-rich environments, whereas cheaters dominated in resource-poor environments. These two outcomes were separated by a sharp transition that occurred at a critical level of resource. These results offer new insights into how the environment affects the evolution of cooperation and highlight the challenges that populations of cooperators face when they experience environmental change.
authors.affiliation: Department of Computer Science and Engineering, Michigan State University, East Lansing, MI, USA.|BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI, USA.
authors.forename: B D
authors.initials: BD
authors.lastname: Connelly
authors.affiliation: BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI, USA.|Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA.
authors.forename: E L
authors.initials: EL
authors.lastname: Bruger
authors.affiliation: Department of Computer Science and Engineering, Michigan State University, East Lansing, MI, USA.|BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI, USA.
authors.forename: P K
authors.initials: PK
authors.lastname: McKinley
authors.affiliation: BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI, USA.|Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA.
authors.forename: C M
authors.initials: CM
authors.lastname: Waters
mesh_terms: D005075:Biological Evolution; D003299:Cooperative Behavior; D004777:Environment; D008962:Models, Theoretical
keywords: 
  Vibrio cholerae
  ; Avida; biofilms; cooperation; digital evolution; experimental evolution; public goods