Chemical communication during tandem running inPachycondyla obscuricornis (Hymenoptera: Formicidae).

Communication during tandem running inPachycondyla obscuricornis is chemically mediated by a pheromone produced in the pygidial gland, which is composed of a cluster of gland cells and an associated reservoir located beween the 6th and 7th tergites of the gaster. The secretion of the gland appears to be transferred to the hindlegs of a tandem pair leader by a series of self-grooming behaviors that occur prior to the formation of a tandem pair. During tandem running, the antennae of the following ant are kept in close contact with the leader's hindlegs and therefore with the chemical signal that provides a communicative bond between individuals.