Using pheromones.
Ants have a unique language that allows them to warn each other of dangers, indicate locations for food searching, motivate gatherings in the anthill, care for the "queen," and feed the young. For ants, "words" are represented by chemical substances known as pheromones.
These substances are produced by exocrine glands, that is, glands of external secretion. During their movements, scout ants leave trails containing pheromones, with a specific concentration of these substances characteristic for each situation. When worker ants encounter such trails, they receive clear instructions on what exactly to do at that moment. Moreover, the scent of pheromones is responded to by ants of a specific species, while other species "speak" in their own distinct language.
Interestingly, even a dead ant continues to emit pheromones. Worker ants care for it as if it were a living being. Even complete immobility does not disturb them. Only after a few days does the smell emanating from the decaying body prompt them to carry it to the "graveyard."
The decomposing substances include certain fatty acids and esters, and if these substances are applied to, for example, a living ant, it will immediately be taken to the graveyard. No matter how many times it returns, it will be removed again at once. This process will continue until the characteristic smell disappears from its body.
