Specialists v. Generalists: from cooperative games to risk of infection

Abstract: Why be a generalist when you can be outperformed by specialists on any given task? Why be a specialist when generalists can tap more resources and better manage risk? These questions arise across multiple fields, and here I take an eco-evolutionary approach to data from the ‘ubiquitous’ opportunistic bacterial pathogen Pseudomonas aeruginosa. I begin with a focus on social behaviors, and ask whether ‘cheat’ lineages can persist on an evolutionary timescale, through specialization on social exploitation. A simple theory model identifies conditions favoring ‘professional cheats’, while data provides partial support. I then conduct a broader comparative genomic survey of niche specialization across P. aeruginosa strains, with data suggesting widespread cryptic convergent specialization on diverse human and environmental niches. Our analyses underline that strains of a ‘generalist’ pathogen species can differ widely in their functional attributes, and provide a path towards defining strain-,  host- and environment-dependent risks of infection. 

Eli Mehlferber, Iris Irby & Sam P Brown