About Ant Trails

Pheromones

• Ants use pheromones to mark out trails from the nest to food sources, or to new nesting sites. A pheromone is defined as a chemical secreted by an animal which is detected by and influences the behavior of other animals. Animals use exocrine glands to create these chemicals, which are then secreted out of the body. Ants release pheromones from the posterior abdomen, which allows them to deposit it behind as they progress to or from a location of interest.

Temporary

• Pheromones secreted by ants are only temporary. The volatile nature of the secreted chemicals means that they are no longer perceptible after only about two minutes of being laid down. Although active trails are constantly refreshed as ants pass over them, the temporary nature has two benefits. One benefit is that the chemical evaporates upwards, onto the receiving antenna of the following ants. Another benefit is that it ensures that the area around the nest will not be covered with old trails leading to exhausted food sources. Using temporary trails eliminates any confusion this may cause.

Broken

• Pheromones are not the only means that ants employ to follow trails left by others. Studies have shown that ants are able to use optical and kinesthetic cues to help them stay on track when pheromone trails have been disturbed. In addition, an ant which loses the trail completely will walk in circles until it either re-engages with the scent, finds another cue, or is found by another ant and shepherded back to the trail.

Creating New

• Studies conducted on Argentine ants -- or Linepithema Humile -- have revealed some interesting traits in their behavior. Scientists allowed the ants to create a pheromone trail and then blocked it with an obstacle, expecting the ants to retrace their steps and attempt to find another food source. Instead, the ants were able to organize into groups to scan the surrounding area for another route to the food source, and then create a new pheromone trail for other ants to follow. This application of autonomous thought within a system has caused scientists and engineers to take note and see if there is anything they can learn from the behavior of ants.