We all know how ants forage for food. A bunch of workers are sent out randomly, then, upon finding some delicious munchie, each worker lays a chemical trail back to her nest in the hopes that other workers will follow suit. Whether or not nest mates do in fact reinforce a given trail is dictated largely by an emergent, semi-random selection process involving factors like the evaporation rate of trail pheromones, distance of a food source from the nest, and the size of the food source. So, that’s how all ants forage for food. Except it’s NOT!
Of course ants, like any insect group worth it’s salt (i.e. ants), exhibit a diversity of styles for any behavior category, and foraging system is no exception. One variation on the standard collective foraging behavior are ant species that forage individually, with workers bringing whatever food they can carry directly back to the nest. But others, like the focal species in a recent paper in Animal Behaviour, are baller termite specialists that first send out scouts and then initiate mass raids of nearby termite colonies.
And this brings us to the 1% and the 99%. In their study, Erik Frank and Dr. Eduard Linsenmair used field and lab experiments to better understand the decision-making processes in the African termite-hunting ant species Megaponera analis. Frank and Linsenmair found that many predictions derived from central place foraging theory are confirmed in this species, and that hunger drives an increase in the number of scouts and decreased selectivity in raiding decisions. But it is the overall implication of their finds that is perhaps most interesting – assessment of possible termite nest targets and communication of that information is entirely determined by individual scouts, and thus it appears that the roughly 1% of the colony that typically serve as scouts make the decisions for the remaining 99%.
No wonder these ants live far, far way from Zuccotti Park!