Evolution of Individual Group Size Preference Can Increase Group-Level Selection and Cooperation

Powers, Simon T.; Watson, Richard A.

doi:10.1007/978-3-642-21314-4_7

Cited by 6 publications

(3 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Alternatively, if the population contains a below‐threshold level of Stx‐encoding bacteria, the selfish nonproducers do not benefit from the presence of Stx‐encoding bacteria (Figure ). The negative dependence of cheater survival on cheater population size leads a dynamic equilibrium distribution of selfish and cooperating individuals in a population (Powers, ). Exotoxin‐encoding bacteria and phage are ubiquitously distributed in the environment, but their occurrence is sporadic or episodic and their environmental persistence varies (Casas et al., ; O'Brien et al., ).…”

Section: Discussionmentioning

confidence: 99%

Cheating, facilitation and cooperation regulate the effectiveness of phage‐encoded exotoxins as antipredator molecules

Aijaz

Koudelka

2018

MicrobiologyOpen

View full text Add to dashboard Cite

Temperate phage encoded Shiga toxin (Stx) kills the bacterivorous predator, Tetrahymena thermophila , providing Stx + Escherichia coli with a survival advantage over Stx − cells. Although bacterial death accompanies Stx release, since bacteria grow clonally the fitness benefits of predator killing accrue to the kin of the sacrificed organism, meaning Stx‐mediated protist killing is a form of self‐destructive cooperation. We show here that the fitness benefits of Stx production are not restricted to the kin of the phage‐encoding bacteria. Instead, nearby “free loading” bacteria, irrespective of their genotype, also reap the benefit of Stx‐mediated predator killing. This finding indicates that the phage‐borne Stx exotoxin behaves as a public good. Stx is encoded by a mobile phage. We find that Stx‐encoding phage can use susceptible bacteria in the population as surrogates to enhance toxin and phage production. Moreover, our findings also demonstrate that engulfment and concentration of Stx‐encoding and susceptible Stx − bacteria in the Tetrahymena phagosome enhances the transfer of Stx‐encoding temperate phage from the host to the susceptible bacteria. This transfer increases the population of cooperating bacteria within the community. Since these bacteria now encode Stx, the predation‐stimulated increase in phage transfer increases the population of toxin encoding bacteria in the environment.

show abstract

Section: Discussionmentioning

confidence: 99%

Cheating, facilitation and cooperation regulate the effectiveness of phage‐encoded exotoxins as antipredator molecules

Aijaz

Koudelka

2018

MicrobiologyOpen

View full text Add to dashboard Cite

show abstract

“…This limit of small group sizes coupled with the aggregation and dispersal movement limits the applicability to real world situations. Although the conditions for such altruism to evolve are restrictive, Powers et al [6] have investigated how these conditions can in fact arise by evolution of individual traits that modify aspects of population structure, such as group size.…”

Section: Introductionmentioning

confidence: 99%

Moderate Contact between Sub-populations Promotes Evolved Assortativity Enabling Group Selection

Snowdon

Powers

Watson

2011

Advances in Artificial Life. Darwin Meets Von Neumann

Self Cite

View full text Add to dashboard Cite

Abstract. Group selection is easily observed when spatial group structure is imposed on a population. In fact, spatial structure is just a means of providing assortative interactions such that the benefits of cooperating are delivered to other cooperators more than to selfish individuals. In principle, assortative interactions could be supported by individually adapted traits without physical grouping. But this possibility seems to be ruled-out because any 'marker' that cooperators used for this purpose could be adopted by selfish individuals also. However, here we show that stable assortative marking can evolve when sub-populations at different evolutionarily stable strategies (ESSs) are brought into contact. Interestingly, if they are brought into contact too quickly, individual selection causes loss of behavioural diversity before assortative markers have a chance to evolve. But if they are brought into contact slowly, moderate initial mixing between sub-populations produces a pressure to evolve traits that facilitate assortative interactions. Once assortative interactions have become established, group competition between the two ESSs is facilitated without any spatial group structure. This process thus illustrates conditions where individual selection canalises groups that are initially spatially defined into stable groups that compete without the need for continued spatial separation.

show abstract

“…In contrast, we are interested in scenarios where individually selected traits affect the strength of group selection or create group selection de novo ( 6). For example, related work addresses the evolution of individually specified traits that affect group size ( 7,8), or the evolution of markers that influence behavioural grouping ( 9). Here we address a multi-species scenario where species can evolve symbiotic relationships that allow explicit control over whether they group and who they group with.…”

mentioning

confidence: 99%

Can Selfish Symbioses Effect Higher-Level Selection?

Watson

Palmius

Mills

et al. 2011

Advances in Artificial Life. Darwin Meets Von Neumann

Self Cite

View full text Add to dashboard Cite

Abstract. The role of symbiosis in macro-evolution is poorly understood. On the one hand, symbiosis seems to be a perfectly normal manifestation of individual selection, on the other hand, in some of the major transitions in evolution it seems to be implicated in the creation of new higher-level units of selection. Here we present a model of individual selection for symbiotic relationships where individuals can genetically specify traits which partially control which other species they associate with -i.e. they can evolve species-specific grouping. We find that when the genetic evolution of symbiotic relationships occurs slowly compared to ecological population dynamics, symbioses form which canalise the combinations of species that commonly occur at local ESSs into new units of selection. Thus even though symbioses will only evolve if they are beneficial to the individual, we find that the symbiotic groups that form are selectively significant and result in combinations of species that are more cooperative than would be possible under individual selection. These findings thus provide a systematic mechanism for creating significant higher-level selective units from individual selection, and support the notion of a significant and systematic role of symbiosis in macro-evolution.

show abstract

Evolution of Individual Group Size Preference Can Increase Group-Level Selection and Cooperation

Cited by 6 publications

References 16 publications

Cheating, facilitation and cooperation regulate the effectiveness of phage‐encoded exotoxins as antipredator molecules

Cheating, facilitation and cooperation regulate the effectiveness of phage‐encoded exotoxins as antipredator molecules

Moderate Contact between Sub-populations Promotes Evolved Assortativity Enabling Group Selection

Can Selfish Symbioses Effect Higher-Level Selection?

Contact Info

Product

Resources

About