Propaganda substances in the cuckoo antLeptothorax kutteri and the slave-makerHarpagoxenus sublaevis

This paper reports the first discovery of "propaganda substances" in a workerless inquiline ant, the European myrmicineLeptothorax kutteri Buschinger. These substances are used by the parasite queen as a chemical weapon for defense against hostile workers of the host speciesL. acervorum. The substances also have an unusual behavioral effect: they cause host workers to attack each other, and they therefore appear to override nestmate recognition in host colonies. Laboratory experiments show that the source of these substances is the Dufour's gland of theL. kutteri queen. Our experiments also confirm the hypothesis that the closely related slave-making antHarpagoxenus sublaevis uses its Dufour's gland secretions as a chemical weapon during slave raids and colony foundation. The behavioral effect of these slave-maker secretions is identical to that ofL. kutteri queens.