How Fire Ants Use Pheromones

Like many other insects, fire ants use pheromones for all kinds of communications. Fire ants use pheromones to mark trails to food and back home, to recognize their queen, to recognize other worker ants from their colony, to alarm the other ants of danger or intruders, and to find dead fire ants.

When there are 200,000 ants in a colony, it would be almost to impossible to recognize every other ant, so fire ants depend on odors or pheromones to recognize other ants that belong to the colony. If another fire has the wrong smell, the intruder is attacked and killed. That way the colony is kept safe. Each fire ant colony has its own odor created by the pheromones and each fire ant has absorbed that odor into her exoskeleton (external skeleton).

Once a fire ant dies and begins to decompose, worker ants recognize the ant as being dead because of the change in odors. They carry the dead ant to the graveyard. When scientists put the dead odor on live ants, nest mates try to carry the live ant to the graveyard.