Pheromone

    Formica sanguinea use pheromones for many tasks. One important task is to lay trails of pheromones that other ants of the colony can follow; this use of pheromones is often seen when observing ants of any species. This use results in long lines of ants going to and from the nest, following the same path.
     Another use for Pheromones is to "tag" their "slaves." The formica sanguinea puts pheromones on their captives, so that they can distinguish them from other colony members, and to help keep track of them so they do not escape.
Pheromones are also used for formica sanguinea communication. See communication.