When communicating, ants rely on their sense of smell for relaying messages to one another. Ants release chemical signals known as pheromones. Other ants are able to detect these pheromones by using their antennae. Once their antennae receive the pheromones, ants determine which direction the rest of the ant colony is going. Also, ants leave pheromones on the ground if they are foraging for food; this allows other ants to know which trail to follow to find food. Ants also use pheromones for rallying other ants to defend their colony or attack other insects.
Ant colonies have social orders and rely on all members of their colonies for survival. Several classes exist in ant colonies; each class has specialized duties that contribute to the colony as a whole. Some ants are responsible for staying in the nest and feeding larvae, while other ants known as "foragers" seek food for the colony. The sole responsibility of queen ants is mating with males for reproduction. After mating with males, queen ants fly away from the colony and find a location to start a new colony.
Foraging is when forager ants temporarily leave the nest to find food for the colony. Ants use their powerful mandibles to grab food and carry it back to their nest. When ants find food items that are too large for one specimen to carry, they form groups to carry the food. One foraging method unique to some species of ants is tandem running, according to Arizona State University's Pratt Lab Research. Tandem running consists of a veteran forager ant leading a young ant to locations where there is an abundant amount of food. This foraging technique allows older foraging ants to mentor young foragers.
Various species of ants have different methods for building nests. Many ant species, such as fire ants, develop their nests on soil. For these colonies, worker ants burrow holes in soil to develop an underground network of tunnels. After building underground tunnels, these ants create mounds and burrow tunnels within the mounds. The purpose of mounds is collecting warmth from the sun, while underground tunnels offer cool, moist environments. Not all ants build nests on the soil. Carpenter ants create tunnels in trees and wooden structures. Some species are nomadic -- army ants and driver ants -- and do not build permanent nesting structures.