Signalling and the evolution of cooperative foraging in dynamic environments

• Published in: PLoS computational biology 2011-09, Vol.7 (9), p.e1002194-e1002194
• Main Authors: Torney, Colin J, Berdahl, Andrew, Couzin, Iain D
• Format: Article
• Language: English
• Subjects: Animal behavior; Animal Communication; Animals; Appetitive Behavior; Biological Evolution; Biology; Computer Simulation; Cooperative Behavior; Evolution; Feeding Behavior; Food supply; Foraging; Genotype & phenotype; Information sharing; Mathematics; Models, Biological; Recruitment; Social interaction; Studies; Swallows; Turbulence models
• ISSN: 1553-7358; 1553-734X; 1553-7358
• DOI: 10.1371/journal.pcbi.1002194

Understanding cooperation in animal social groups remains a significant challenge for evolutionary theory. Observed behaviours that benefit others but incur some cost appear incompatible with classical notions of natural selection; however, these behaviours may be explained by concepts such as inclusive fitness, reciprocity, intra-specific mutualism or manipulation. In this work, we examine a seemingly altruistic behaviour, the active recruitment of conspecifics to a food resource through signalling. Here collective, cooperative behaviour may provide highly nonlinear benefits to individuals, since group functionality has the potential to be far greater than the sum of the component parts, for example by enabling the effective tracking of a dynamic resource. We show that due to this effect, signalling to others is an evolutionarily stable strategy under certain environmental conditions, even when there is a cost associated to this behaviour. While exploitation is possible, in the limiting case of a sparse, ephemeral but locally abundant nutrient source, a given environmental profile will support a fixed number of signalling individuals. Through a quantitative analysis, this effective carrying capacity for cooperation is related to the characteristic length and time scales of the resource field.