Topochemical learning in black carpenter ants (Camponotus pennsylvanicus)

Following chemical trails to food sources has been well documented in ants, but extra social chemical learning in these organisms is virtually uninvestigated. The "topochemical sense" hypothesis, presented a century ago, proposes that foraging ants navigate using local 'chemical emanations'. This hypothesis is supported by the results of our study in which black carpenter ants, Camponotus pennsylvanicus, on their way to and from a food source, learned to identify a place on their route by recognizing preexisting chemicals of plant substrates. They associated this learned chemical stimulus with the decision to climb vertically in order to find food.