Cooperative foraging in the ant Temnothorax rugatulus: Recruitment, advantages of group size, and collective decision-making

Ants in the genus temnothorax have become one of the leading model systems for the study of collective decision-making. The challenges most often presented to these ants are house-hunting dilemmas. Scout ants recruit other nest-mates to a new home through the use of tandem runs and active transport. The strength of this recruitment has been compared to that of honeybee waggle-dancing in terms of its 'linearity'. In contrast, pheromone trail-laying ants such as Lasius niger show non-linear recruitment. More ants laying a trail, make the trail more appealing to future foragers. Temnothorax ants share another quality with honeybees--namely, they utilize the same recruitment technique to lead others to prospective homes and to food. In the case of honeybees it is the famous waggle-dance. In the case of temnothorax it is the tandem run. In fact, these ants tandem run more strongly in a foraging context than in house-hunting. Given their durability, experimental tractability, and replicability - temnothorax ants have allowed us to investigate some basic questions in collective foraging which may shed light on such issues as the advantages of group size and the importance of linearity versus non-linearity in collective decision making.