Learning through the waste: olfactory cues from the colony refuse determine plant preferences in foraging leaf-cutting ants

ROCES, FLAVIO; A. ARENAS

Klosterneuburg

Encuentro; IUSSI 2019 - Central European Meeting of the International Union for the Study of Social Insects; 2019

Leaf-cutting ants are polyphagous herbivores that show distinct preferences in the choice of plants for their symbiotic fungus. Foragers are knownto reject previously accepted plants if they prove to be unsuitable for theirfungus once incorporated into the nest, a phenomenon that involves olfactory avoidance learning. Waste particles removed from the garden likelycontain cues originating from both the unsuitable plant and the damagedfungus. We investigated whether Acromyrmex ambiguus leaf-cutting antslearn to avoid unsuitable plants solely through olfactory cues available atthe colony dump. Evidence on the influence of waste?s olfactory cues ondecision making by foragers was obtained by scenting and transferringwaste particles from subcolonies that had been fed either fungicide-treated or untreated leaves. Results from individual binary-choice experiments indicated that foragers learn to avoid plants unsuitable for the fungus by associating plant odours and cues from the damaged fungus thatco-occur in waste particles. It is argued that olfactory cues at the dumpenable foragers to predict the unsuitable effects of plants even if they hadnever been experienced in the fungus garden, and that waste particlesmay contribute to spread information about noxious plants for the funguswithin the colony.