Ants are mostly known to communicate via scent and chemical signals called pheromones. The most classic example, for instance, being the usage of such pheromones to leave a trail as they forage. However, ant communication isn’t limited to just scent as they can also pass information through sound, trophallaxis, and touch.
In this article we’ll discuss the different modes of communication that ants use and look into some examples of how they use them.
Ants possess a highly-developed sense of smell. Through their antennae, they can pick up different scents including chemical signals called pheromones to communicate a wide range of information. Again, this includes the ever classic example of the pheromone trails that they use when foraging.
When successful foragers find a food source, they deposit pheromones on their return to the nest to leave a trail which other workers can detect and follow. This trail then becomes reinforced as more and more workers add pheromone to it. In that way, the ants inform each other that the trail is good and that it still leads to food. Should the food run out, the trail eventually decays off as the foragers refrain from reinforcing it on their return, allowing the existing pheromone to evaporate.
Aside from the trails, ants also use chemical signals to identify nest-mates from intruders. Ant bodies are covered by a layer of cuticular hydrocarbons which they can perceive through direct antennal contact or at short distances. Research has found through the study of the workers of the carpenter ant Camponotus herculeanus, that ants use these cuticular hydrocarbons to determine nest-mates and non-nest mates. For example, the presence of additional hydrocarbons or odor cues novel to a colonies own cuticular hydrocarbon profile, elicits an aggressive reaction.
Lastly, ants also use these pheromones to detect and identify dead ants. When ants die, they release a death pheromone called oleic acid which then triggers necrophoric behavior. Fun fact, research has found that even living ants bathed in oleic acid are treated as if they are dead and also trigger necrophoresis.
Ants are mostly believed to be deaf, which is why it’s quite surprising that they make use of sounds to communicate. While they can’t hear air-borne sounds, they’re actually capable of detecting sound through substrate-borne vibrations. And through these vibrations they’re able to send different types of signals depending on how the sound is produced.
Ants produce sounds in two different ways, drumming and stridulation. To drum, ants repeatedly strike the substrate with their bodies. It’s often used by some ant species to send alarm signals whenever there’s a disturbance in the colony nest.
Stridulation on the other hand, is done by rubbing two sections of the gaster together. This produces a chirp-like sound which may be used as an alarm signal, a mating signal, or to simply complement chemical communication.
Trophallaxis is a social-fluid exchange found in social insects like ants. It typically refers to feeding through mouth-to-mouth transfer of food and nutrients. Aside from nutrients however, research has found that ants also use trophallaxis to pass information.
For example, ants use the fluid created by trophallaxis to share information or memories regarding a food source. This information has been shown to affect foraging behavior and have prompted ants to forage for food they would have otherwise avoided.
Trophallaxis has also been shown to affect how ants interact with other animals that they have yet to encounter. In the ant species Tetramorium tsushimae for example, ants that don’t engage in mouth-to-mouth fluid transfer tend to be aggressive towards aphids. However, those that have never tended aphids, but have engaged in trophallaxis with nestmates that have, exhibit reduced aggressiveness towards aphids instead.
Lastly, ants are also known to communicate touch. For example, African weaver ants antennate or touch each other’s antennae during recruitment for food finds or for defense against intruders.
One study has also suggested that ants can even provide directions through antennation. It states that Lasius niger ants returning from a food source can communicate to outgoing foragers directions through physical contact on a trail. A further study that tried to replicate these findings however, failed to find evidence for physical communication of food location once pheromone cues were eliminated from the equation. Which somehow makes sense, as why should ants need to communicate physically when they can provide more accurate information through pheromones?
Nonetheless, the latter study concludes that while it most certainly increases the burden of proof required for claims of physical communication of direction in ants, it doesn’t rule out its possibility. Simply put, we still have much to learn.
Can Ants Hear?
Ants can hear, but not in the same way as us humans. Most scientists agree that ants are deaf to airborne sounds but can instead detect sound through substrate-borne vibrations. That said, a recent study has suggested that ants may be able to hear airborne sounds in the near-field wherein such sounds are amplified, but this study isn’t well supported.
How Do Ants Find Food?
Ants find food by foraging. Ant colonies send out worker ants, which travel long distances and use their keen sense of smell to find food. Once they locate a food source, they then recruit fellow workers through the use of pheromones and other modes of communication.
Summary: How Do Ants Communicate?
Ants mostly communicate through scent and chemical signals called pheromones. They use these pheromones to leave trails when foraging, identifying colony mates, and even identifying the dead.
Aside from that, they may also use sound, trophallaxis, or touch. Despite these three being less developed than chemical communication, each of these function to help ants pass on important information to their nestmates that may very well affect their chances of survival.