Army ant, also called the legionary ant, is an insect that travels in large groups to hunt for prey. Army ants conduct raids with groups of 100,000 to 20 million individuals. Working together, the ants overwhelm and consume nearly any insect or other small animal in their path. There are more than 300 species (kinds) of army ants. They are found in most warm areas of the world, but especially in tropical Central and South America. Army ants of Africa and Asia are often called driver ants.
Army ants have long legs compared with most other ants. They are blind, relying on scent and touch. They range in color from a deep golden to dull brown to black. Army ant groups are called colonies. Each colony usually consists of one queen, a large number of workers, and a group of developing young. Army ants vary in size from 1/10 to 1 1/5 inches (3 to 30 millimeters) long. They have long, curving jaws called mandibles. Workers have a venomous sting.
Army ants conduct their raids on the ground and in trees at heights of up to 65 feet (20 meters). Raids typically begin at dawn, when workers move into the surrounding area in columns or swarms. These ants work together to overcome obstacles. For instance, they might cross a gap between trees by hooking their bodies together, forming a living “bridge” of ants. Army ants seize other ants, beetles, centipedes, grasshoppers, roaches, scorpions, spiders, tarantulas, snakes, lizards, and ground-nesting birds. They are not a threat to large animals or to people. Army ants consume so much prey that they must frequently move to a new area to find food.
Army ants typically alternate between nomadic and stationary periods. Unlike most ants, they do not build permanent nests. Instead, they form temporary nests called bivouacs. The colony remains in one location for two to three weeks while the queen lays 100,000 eggs or more. After the eggs hatch, the colony has many hungry larvae (young) to feed. The colony then becomes nomadic, moving to a different location nearly every night. Workers carry the queen and the larvae. Each morning, the colony sends out workers to hunt for food for the young. In time, the larvae mature into pupae, which do not require food (see Ant (Reproduction)). The colony then returns to a stationary lifestyle while the pupae develop into adults. The queen lays another batch of eggs, and the cycle begins again.
See also Ant (Army ants).
