To the beat of their own drum: The role of vibratory communication in western carpenter ants

When threatened, many social insects produce alarm signals to alert and recruit nest mates. Ants commonly communicate distress using both pheromonal and vibratory signals. Functions of alarm pheromones in ants have been intensely studied but the role of vibratory communication signals is largely unknown. Distressed Camponotus carpenter ants both secrete alarm pheromone and drum body parts against the substrate, thereby generating substrate-borne vibrations. We have previously shown that the alarm pheromone of Western carpenter ants, Camponotus modoc, elicits attraction of nest mates. Here, we tested the hypotheses (1) that the vibratory drumming signal increases nest mate alertness, and (2) that vibratory and pheromonal signals in combination elicit the strongest and fastest recruitment responses from nest mates. To test these hypotheses, we video-recorded the behavior of groups of ants on wood veneer in response to (i) Laser-guided play-back recordings of vibratory signals, (ii) synthetic alarm pheromone, or (iii) both. Data collection and analyses were still under way by the due date for abstract submission