Acoustic communication by ants

Effective communication is essential in highly organized ant societies. Currently myrmecologists believe that pheromones play the central role in ant communication and that relatively little is accomplished with sound. However many ant species make sounds by stridulating, i.e., running a scraper over ridges on their abdomen. Hence, it seems likely that ants communicate using a combination of pheromones and sound. Because ants appear insensitive to airborne sound, myrmecologists have concluded that stridulatory signals are transmitted through the substrate. However, this conclusion is untenable for a number of reasons. How then can ants transmit signals through the air when apparently they are insensitive to airborne sound? The answer lies in the fact that ants are much smaller than the wavelength of the sound they generate, so there is a relatively significant near field surrounding a stridulating ant. The near field is characterized by a major increase in the particle velocity of sound, which can be detected by hair‐like sensilla on the apical segments of the ants’ antennae. By sensing the relative difference in particle sound velocity between the antennae, an ant can detect stridulation signals from a nearby ant, yet appear deaf to extraneous airborne sound.