Few years back, computer scientists have been fascinated the way in which a colony of ants can solve complex problems; in particular, how it finds the shortest route to a food source.
Each insect in a colony seemed to have its own agenda, and yet the group as a whole appeared to be highly organized. This organization was not achieved under supervision, but through interaction among individuals. This was most apparent in the way in which ants travel to and from a food source. Ants form and maintain a line to their food source by laying a trail of pheromone, i.e. a chemical to which other members of the same species are very sensitive. They deposit a certain amount of pheromone while walking, and each ant prefers to follow a direction rich in pheromone.
This enables the ant colony to quickly find the shortest route. The first ants to returns should normally be those on the shortests route, so this will be the first to be doubly marked by pheromone (once in each direction).
Studying this uncanny skill has enabled researchers to create software agents capable of solving complex IT problems, such as rerouting traffic in a busy communications network.
Reference: http://answersingenesis.org/creation/v24/i1/ants.asp
