Estigmergia

Term introduced by the French zoologist Pierre-Paul Grasse in 1959.
Estigmergia: Greek stigma (mark, sign) + ergon (action, work), the term refers to the notion that an action of a particular agent ceases signals in the environment, and this signal can be perceived by other agents (usually the same species) in order to incite or determine its subsequent actions. In real ants, this signal (or communication) is made by deposition of pheromone in the environment.
The shortest paths emerge from the collective behavior through:
A choice location and probability of each ant on where to move, and most likely paths that have more pheromones.
An indirect way of communication (Estigmergia), when the ants leave a trail of pheromone, modify how the next ants shall go see the local terrain, influencing the choice of the next way forward ants.
When reading / writing the pheromone chemical signal in a local ants are communicating indirectly via the environment