Like us humans, ants have the ability to hear. They can pick-up and interpret sounds through vibrations which they then use to communicate. But since they don’t have ears, their sense of sound and the way that they process it varies greatly from ours.
In this article we’ll look deeper into how ants perceive sound and how they use sound to communicate.
How Do Ants Hear?
Studies have long revealed that ants are essentially deaf to airborne sounds but extremely sensitive to their substrate-borne components. This means that while ants aren’t capable of hearing sounds like speech or music, they hear sound through vibrations transmitted through solid objects instead.
They do so through the subgenual organ, a major type of chordotonal organ and primary receptor for substrate-borne vibrations that’s located below the knee in the tibia of all their legs.
Can Ants Hear Sounds In The Near-Field?
A relatively recent study claimed that ants mainly communicate through the air and acoustic receptors in their antennae that respond to particle sound velocity. The study argues that while ants are unresponsive to most airborne sounds, they are capable of picking-up such sounds in the near-field wherein they’re enhanced.
However, a follow-up study challenged this claim and found that the amplitude of the near-field particle oscillation around a stridulating ant was fifty times lower than the sensitivity threshold of their antennae and Johnston organ. Suggesting that it’s impossible for ants to detect these signals and that ants are in fact insensitive to sounds even in the near-field.
Either way, further research is needed to fully determine whether or not ants can’t actually hear through the air. After all, if other insects are capable of doing it, why can’t ants?
How Do Ants Use Sound?
Despite their auditory system being relatively underdeveloped, ants make use of sound to communicate in conjunction with their use of pheromones. To do so, they produce sounds in two ways, drumming and stridulation.
Drumming is a form of sound production most commonly found in social insects that live in wooden nests, wherein substrate vibrations are transmitted with high efficiency. It’s used as an alarm signal and is usually produced when there’s a disturbance to the colony nest.
For example, whenever carpenter ants perceive contaminations or signs that their nest has been breached, they start drumming by rocking their bodies violently back and forth to strike the substrate with their mandibles and gaster. This allows them to notify their colony mates which then respond by either becoming immobile or speeding up to move towards the source of the vibration.
Stridulation on the other hand, is considered a more sophisticated sound-producing behavior. To do so, ants move their gaster in such a way that they cause a segment of the gaster with a patch of tiny ridges like a file, to rub a scraper in another segment. This results in a chirp that ants use to convey information.
So far, scientists have discovered three ways that ants use stridulation. They are as follows:
Alarm Signal. Like drumming, ants also use stridulation as an alarm. For instance, ants of the genus Atta have been shown to stridulate when they get buried and trapped so as to notify their nestmates and initiate rescue digging. Similarly, other ants also stridulate when they are pressed beneath an object or restricted to a small space.
Mating Signal. Young queens of Pogonomyrmex ants have shown to use stridulation during mating. Once their spermatheca has been filled, these young queens start stridulating to send out the signal to stop mating. This let’s them inform pursuing males of lost mating chances and at the same time, allows them to escape and start building up their colonies.
Complement to Chemicals. Finally, studies have also discovered that some ant species use stridulation to enhance chemical communication when recruiting nestmates for food finds, new nest sites, or both.
Do Ants Have Ears?
Like many invertebrates, ants don’t have ears. Such is why they can’t detect sound in the same way that we humans do. Instead, they rely on vibrations and detect them with their subgenual organ located near their feet.
How Do Ants Communicate?
Ants mostly communicate using scent and chemical signals called pheromones which they can detect using their highly sensitive antennae. For example, ants may use pheromones to leave a trail when foraging for food, to identify nest mates, and to identify their dead.
Apart from pheromones, ants may also communicate using body language, touch, and as demonstrated in this article, sound.
Can Ants See?
Most ants, apart from the blind subterraneans can see through a visual system composed of compound eyes and ocelli which detects movement, light, and color.
It’s amazing that despite their lack of ears, ants have developed their own system to detect and decode sound. While they can’t detect sound waves from the air, they can hear through their subgenual organs which detect vibrations passing through solids. With that, they’re are capable of using sound to communicate, and they do in fact do so through stridulation and drumming which they use to send out alarm, mating, and recruitment signals.