Ants typically use trail pheromones to coordinate roles like nest defense and foraging. Ants can produce a trail of defensive secretions that trigger an alarm response within their nestmates. In regards to foraging, an ant can communicate the quality of a food source to its colony; the more rewarding a food source is, the higher the concentration of the trail produced. Additionally, some species, like Lasius niger ants, can "eavesdrop" on the trails produced by another species in order to procure food.
Myrmicine ants produce their trail pheromones through their poison glands. The major component in the trail pheromones secreted by Pristomyrex pungens is 6-n-pentyl-2-pyrone; several monoterpenes were also found in the secretion, but they provided only marginal effects when combined with the former. The major components found in the secretions of Aphaenogaster rudis include anabaseine, anabasine, and 2,3'-bipyridyl, though the third contributes less than the other two. When secreted, this trail pheromone does not recruit ants directly from their nest; instead, worker ants may stumble upon to the trail unintentionally and follow it thereafter to the food source.