The refuse dump provides information that influences the foraging preferences of leaf‐cutting ants

Abstract

The ability to respond to local stimuli individually and propagate information among colony members has allowed social organisms to generate collective responses. Leaf‐cutting ants are an excellent model to study this because, apart from exchanging information among groups assigned to different tasks (foragers, gardeners, and midden workers—ants working in refuse dumps), they also do so with their symbiotic fungus. Here, we tested the role of refuse dumps as an information centre influencing the foraging decisions of Acromyrmex lobicornis under field conditions. To simulate the presence of discarded resources, oat flakes were added to the refuse dumps of treated colonies, while the refuse dumps of controls remained untreated. After 24 h and for 6 weeks, we offered new clean oat flakes on the foraging trails simultaneously with cornflakes, another palatable resource that was never experienced by the ants on the dump. Although the oat flakes were suitable for the ants and harmless to the fungus, the acceptance index—a ratio of oat flakes foraged to total oat and cornflakes offered—decreased by 55% 24 h after the ants interacted with oat flakes in the refuse dump. After 6 weeks, the acceptance index recovered to levels that did not differ from initial values. Therefore, ants might use waste to obtain information about the suitability of resources found in foraging trails. We explore potential mechanisms underlying the transmission of information from refuse dumps to foraging trails, shedding light on the intricate dynamics of collective decision‐making in social insect colonies.