How do Ants Talk to Each Other? What do They Say?

8 novembre 2024

Ants are one of the most social and successful groups of organisms on Earth, with colonies that can range from a few dozen individuals to millions. Despite their small size, ants are capable of highly sophisticated communication, using a variety of systems to coordinate tasks, defend the colony, and share information. Much of their communication happens invisibly, through the use of chemical signals, touch, and even sound. In this article, we’ll first explore how ants communicate, focusing on the specific organs and mechanisms that facilitate this communication, and then take a closer look at the messages ants are sending to each other.

Summary

1. How Do Ants Talk to Each Other?

Ants have unique ways of “talking” without words. They use smells, sounds, and touch:

Smell: Ants leave scent trails called pheromones to show other ants where food or the nest is.
Sound: By rubbing their bodies, ants make quiet sounds that other ants can feel as vibrations, letting them know if there’s danger or if they need help.
Touch: Ants use their antennae to greet each other and share information, like a special handshake.

2. What Are Ants Telling Each Other?

Ants communicate important messages to keep their colony safe and organized:

Finding the Way: Pheromone trails guide other ants to food or back home.
Danger: An alarm pheromone warns others of a threat.
Territory: Special scents mark areas as the colony’s home.
Help Wanted: Signals call for extra ants to help with big tasks.
Identity: Each ant has a unique colony smell, helping them know who’s part of their group.
Sharing: Ants tap each other to ask for food or assistance.

How Do Ants Communicate?

Ants communicate using a combination of chemical signals, sounds, and physical touch. These methods of communication allow ants to live and work together in complex colonies. Unlike humans, who primarily use vocal language and visual cues, ants rely heavily on pheromones—chemical substances produced by specific glands. These chemical signals enable ants to convey various messages, from marking food trails to signaling danger or recruitment for a specific task.

Acorn ant workers in a hollow stick

Communication in ants is not just a simple exchange of signals but a highly organized system that ensures the colony functions smoothly. For ants to communicate effectively, they have evolved specialized organs and systems to produce and detect pheromones, as well as other forms of communication.

Chemical Communication: The Role of Pheromones

Chemical communication is the most important form of interaction between ants, and it is facilitated by a variety of specialized glands and sensory organs. At the core of ant communication are pheromones, chemical signals that ants produce and release into their environment. Pheromones are detected by antennal sensilla, tiny hair-like structures located on the antennae that are capable of sensing specific chemical compounds.

The Antennae: The Sensory Organs

The antennae of ants are their primary sensory organs. Each ant has a pair of antennae, and these organs are covered with thousands of sensory hairs (or sensilla) that can detect chemicals in the environment. These sensilla are highly specialized to sense different types of stimuli, including pheromones. They are also sensitive to other environmental factors such as humidity, temperature, and touch.

Diacamma ant often use antennae to solicit trophallaxis to share food, courtesy of Taku Shimada

Ants use their antennae not only for detecting pheromones but also for tactile communication. When ants encounter each other, they often tap their antennae together in a process called antennal drumming, which allows them to exchange additional chemical and tactile signals.

Pheromone-Producing Glands

The pheromone-producing glands are responsible for creating the chemical signals ants use to communicate. Ants possess a variety of glands, each serving a distinct function in the communication process.

Diagram and location of various pheromone-producing glands in ants

- Dufour’s Gland: This gland is one of the most important for communication, especially for marking trails and territories. It produces pheromones used in foraging and marking new territories, as well as in certain defensive behaviors. The chemicals produced by the Dufour’s gland are released in droplets that ants deposit onto surfaces, which other ants can later detect with their antennae.
- Poison Gland: Located in the abdomen, this gland produces toxic substances used for defense, but it also plays a key role in producing pheromones for alarm signals. When an ant is injured or feels threatened, it releases alarm pheromones from its poison gland, triggering an immediate response from other ants.
- Gaster and Pygidial Gland: The pygidial gland is involved in alarm communication, especially in response to threats. Ants can also use their gaster (the abdominal region) to produce specific pheromones when marking nest entrances or defending their territory.

Communication through Sound

While chemical communication is the primary method, ants also use sound as a form of communication, although less frequently. Sound communication in ants is mainly used within the nest and during aggressive encounters. Ants produce sound through stridulation, which involves rubbing certain body parts together to create vibrations or noise.

Stridulation: Rubbing Body Parts Together

Stridulation is an important form of communication for ants, especially in species like harvester ants and army ants. This type of sound is produced when certain body parts are rubbed together, similar to the way crickets might chirp. For example, some ants have specialized structures called stridulatory organs on their thorax, which produce a buzzing or chirping sound when scraped against other body parts.

Listen to Bullet Ants (Paraponera clavata) "Stridulate"

Stridulation is often used as an alarm signal or during territorial disputes. When two colonies come into contact, stridulation can be heard as a form of aggressive behavior, signaling an impending fight. The sound may also serve to alert other colony members to an intruder or danger, prompting them to join the confrontation.

Vibrational Signals

Some ants also communicate using vibrations. These are often subtle and occur within the nest, where ants may tap or vibrate the ground to send signals to other members of the colony. This form of communication is most commonly used by species that have a dense social structure, like leafcutter ants, where rapid and coordinated responses to signals are critical.

Here is a carpenter ant colony producing vibrations by hitting their heads against the wall loudly enough to be heard by ear.

Communication through Vision and Touch

Although ants have relatively poor vision compared to other animals, they still use vision and touch as additional forms of communication, particularly for short-range interactions and when they need to exchange immediate information.

Vision

Ants rely on compound eyes, which are made up of many individual lenses called ommatidia. These eyes allow ants to detect movement and light, but their resolution is not as sharp as that of animals with more developed vision. As a result, ants do not rely on visual cues for long-distance communication but use their eyes mainly for orientation and detecting movement in the immediate surroundings.

The ability to detect light and motion is essential for tasks like navigating back to the nest, identifying potential threats, or recognizing landmarks.

Touch: Antennae and Tactile Interaction

Touch is perhaps the most fundamental form of communication in ants. They use their antennae for tactile interactions with one another, constantly touching and tapping to exchange chemical signals. This direct contact helps ants recognize one another, solicit assistance, or guide others to a food source or a nest entrance.

Tandem running is when one ant leads another (for example, to a food source, by touch)

Tandem running is an example of touch-based communication. When a forager finds a food source, it will return to the nest and lead another ant to the resource by physically guiding it with its antennae. This behavior ensures that ants can efficiently transport resources and share information about food sources.

What Are The Ants Telling Each Other?

Now that we’ve explored the organs and mechanisms used by ants to communicate, let’s dive into the specific messages ants send to each other. Ants convey a wide range of information, from marking trails to identifying threats and recruiting help for a task.

Trail Pheromones

One of the most well-known forms of communication in ants is the use of trail pheromones to guide foraging and other colony activities. When an ant finds food, it leaves behind a trail of pheromones that other ants follow to the food source. This is a highly effective way for ants to coordinate large-scale foraging expeditions.

Army ant columns navigate and coordinate by using trail pheromones

The strength of the trail varies based on the distance to the food and the quantity available. The more ants follow the trail, the stronger it becomes, creating a feedback loop that ensures efficient use of the colony’s resources. In some species, such as army ants, the ants will lay a trail to form a foraging column, maximizing the chances of finding food quickly and efficiently.

Alarm Pheromones

When an ant is in danger or encounters a threat, it releases alarm pheromones. These chemicals trigger a fight-or-flight response in other ants, often leading to a rapid assembly of worker ants to defend the colony. Alarm pheromones serve as an early warning system, alerting ants to dangers like predators or intruders.

An Army Ant Soldier (Eciton sp) Releases Alarm Pheromones to Request Backup

Alarm pheromones also help ants organize defensive behaviors, such as swarming an attacker or retreating to the nest. The intensity of the alarm signal determines the urgency of the response.

Territories and Home Range

Ants are territorial creatures, and they use pheromones to mark their territory and define their home range. Territorial pheromones are deposited around the nest entrance and along the edges of the colony’s territory to signal to other colonies that the area is already claimed.

Pavement Ants (Tetramorium sp) have large wars every spring to determine territorial conflicts

These markers help prevent conflicts between colonies and direct ants to forage in safe, designated areas. In some species, such as weaver ants, workers deposit pheromones to define the boundaries of their territory and prevent encroachment from other ant colonies.

Recruitment

Ants also recruit others to help with tasks like foraging, defense, and nest-building. When an ant finds a food source or encounters a need for help, it releases pheromones that guide other workers to the site. The more ants that reinforce the pheromone trail, the stronger the recruitment signal becomes.

Identity (Cuticular Hydrocarbons)

Ants use cuticular hydrocarbons to communicate their identity and distinguish nestmates from outsiders. These chemicals are present on the surface of an ant’s exoskeleton and act as a colony-specific signature. When ants from different colonies encounter one another, they may engage in aggressive behavior if the chemical signals do not match.

Ants use cuticular hydrocarbons to identify friend and foe

This system helps prevent intruders from entering the nest and ensures the colony’s social order is maintained.

Soliciting Food or Assistance

Lastly, ants use chemical signals to solicit food or assistance. Ants may exchange food through trophallaxis—the regurgitation of liquid food from one ant to another. This not only provides nourishment but also helps distribute important information, such as the discovery of a new food source or changes in the nest environment.

Ants may also solicit help by tapping their antennae or releasing specific pheromones, signaling the need for assistance in tasks such as defending the nest or moving heavy objects.

The Complex Language of Ants

Ants have developed a highly sophisticated system of communication, utilizing chemical signals, sound, touch, and even visual cues to interact with one another. Through the use of specialized glands and sensory organs, ants are able to convey a wide range of messages, from marking trails to signaling danger or coordinating group activities.

This complex system of communication allows ants to function as a highly organized superorganism, working together to ensure the survival and success of the colony. Whether through pheromones, sound, or touch, ants demonstrate the power of cooperative communication in the animal kingdom, and their ability to communicate effectively is one of the reasons why ants are among the most successful creatures on Earth.

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