Network of recruitment communication among colony members. Each node represents an ant and each line represents the recruitment of one ant by another.
The choice of a nest site depends heavily on information sharing among the scout ants who organize the colony’s move. These ants use a behavior called tandem running to recruit fellow scouts to candidate sites. Scouts fully commit to a site only when its population reaches a minimum value, or quorum. By using this rule they combine their own direct evaluation of the site with an indirect cue about the judgments of other ants. This balancing of personal and social information is a general feature of collective decision-making, and quorums may offer a widespread mechanism for balancing the advantages of shared decision-making with the dangers of “groupthink”. We have adopted a network approach to information sharing among scouts, giving us a synoptic view of how recruitment communication spreads information through the colony. The results suggest the importance of heterogeneity among scouts, with some consistently playing an outsize role. This contrasts with earlier views that all scouts are much the same.