What chemical signal do ants commonly use to mark trails to food?

Ants commonly use pheromones to mark trails leading to food. A worker lays chemical secretions on the substrate, and nestmates detect and follow the resulting odor trail.

Trail pheromones allow many workers to coordinate without spoken sounds. As more ants follow and reinforce a successful route, the trail can become stronger. It may later fade as the chemicals evaporate or are no longer renewed, helping the colony redirect effort when conditions change.

Ants use many other pheromones for alarm, nestmate recognition, recruitment, and reproduction. The exact chemical differs among species, so there is no single universal ant trail pheromone.

A pheromone is a chemical signal released by one member of a species and detected by others of the same species. It is not the same as a hormone, which acts inside an organism. Ants also communicate through touch, vibration, and limited acoustic signals, but trail marking is most famously chemical.