Tandem calling: a new kind of signal in ant communication.

Leptothorax acervorum, L. muscorum, and L. nylanderi recruit nest mates to a new food source by tandem running, with only one nest mate being recruited at a time. This technique is initiated by a special "tandem calling" behavior; the recruiter slants its gaster upward and discharges poison gland secretions from the extruded sting. Nest mates are attracted, and as soon as one of them touches the calling ant, tandem running starts. Further details of the full recruitment sequence are provided. Evidence is presented to suggest that tandem running is the evolutionary precursor of odor-trail communication and sex attraction within certain phylogenetic lines of myrmicine ants.