Distributed leadership and adaptive decision-making in the ant Tetramorium caespitum.
In the ant species Tetramorium caespitum, communication and foraging patterns rely on group-mass recruitment. Scouts having discovered food recruit nestmates and behave as leaders by guiding groups of recruits to the food location. After a while, a mass recruitment takes place in which foragers follow a chemical trail. Since group recruitment is crucial to the whole foraging process, we investigated whether food characteristics induce a tuning of recruiting stimuli by leaders that act upon the dynamics and size of recruited groups. High sucrose concentration triggers the exit of a higher number of groups that contain twice as many ants and reach the food source twice as fast than towards a weakly concentrated one. Similar trends were found depending on food accessibility: for a cut mealworm, accessibility to haemolymph results in a faster formation of larger groups than for an entire mealworm. These data provide the background for developing a stochastic model accounting for exploitation patterns by group-mass recruiting species. This model demonstrates how the modulations performed by leaders drive the colony to select the most profitable food source among several ones. Our results highlight how a minority of individuals can influence collective decisions in societies based on a distributed leadership.
Collignon
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B
Service d'Ecologie Sociale CP. 231, Université Libre de Bruxelles, Campus Plaine, Boulevard du Triomphe 1050, Brussels, Belgium. bcollign@ulb.ac.be
Detrain
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C
D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D001000:Ants / Q000502:physiology*; D003657:Decision Making; D005247:Feeding Behavior; D008954:Models, Biological; D012919:Social Behavior; D013269:Stochastic Processes