What chemical trail do ants commonly lay to guide nestmates to food?

A pheromone trail is the chemical trail ants commonly lay to guide nestmates to food.

A worker ant that discovers a useful food source can deposit a pheromone as it returns to the nest. Other workers detect the chemical with their antennae and follow the route. If the food remains valuable, repeated traffic can reinforce the trail; if it disappears, the signal fades and the route is abandoned.

Different ant species use different chemicals and trail systems. A colony may also use pheromones for alarm, nest recognition, recruitment, and mating. Trail strength can therefore carry practical information about how profitable or urgent a route is.

Pheromone trails are not spoken messages or permanent maps. They are temporary chemical signals whose effects depend on concentration, evaporation, weather, and the behavior of the ants encountering them. Ants can combine this chemical guidance with visual landmarks and the sun’s position.