Ants are deaf.

Workers of a number of ant species produce vibrational signals, a phenomenon called ‘‘stridulation,’’ with a specialized organ located on their gasters. Even though stridulation can be heard by humans as faint air-borne sound, it has repeatedly been shown that ants are insensitive to the air-borne components of such signals. Instead, they are highly responsive to their substrate-borne components. Contrary to this view, it has recently been claimed that fire ants can hear stridulatory signals produced by nest mates as near-field sound, and that there is no evidence of signal transmission through the substrate in ants. In the present letter, this view is challenged by calculating the amplitude of the near-field particle oscillation around a stridulating ant, and by comparing it with the sensitivity threshold of the ant sensory receptors. The amplitude is shown to be at least 50 times lower than the sensitivity threshold, a fact that precludes the perception of the signals with the stiff antennal sensilla ~and Johnston organ! so far described for ants. Finally, published data and our own findings on vibrational communication in ants are summarized, clearly showing that they are highly responsive to the substrate-borne components of stridulatory signals, and insensitive to near-field sound. © 2001 Acoustical Society of America. @DOI: 10.1121/1.1370085#