Army Ants

army ants in the Amazon

Common Name: Army Ants

Order Name: Hymenoptera

Family Name: Formicidae

Army ant is a name that people use for ants that move in a line killing every insect and small animal in their path. People use other names for these ants, including Driver Ants, Legionary Ants, and even Visiting Ants.

Scientists describe army ants as ants that have two characteristics: migration or nomadic lifestyle and group predation. There are actually several different species of ants that behave this way. Some live in Africa and some live in South and Central America.

Army ants live in temporary nests. They seldom make underground burrows like other ants. The temporary nests, or bivouacs, are places where the ants rest between their hunting raids. The bivouac might be inside a hollow log, or it might be out in the open.

The ants often make the bivouac hanging from a tree limb. Thousands of workers will link their legs and their mandibles (jaws) and make an enclosed hammock for the queen. Sometimes the workers enclose the immature ants inside the hammock as well.

The army ants stay in the bivouac for a few weeks. Once queen comes out of the resting place and the colony starts to migrate.

Some species of army ants migrate in line. Other species migrate in a fan-shaped wave of ants. Many thousand ants move at once. The soldier ants march at the side of the column to defend the queen.

During the march, some of the workers carry the immature ants. Other workers gather all the food that they can find. As they go, the workers kill every insect, spider, snake, and lizard in their path. Birds and animals hear the ants marching and try to get out of the way.

As they march, the ants can climb trees or shrubs. They have been known to go through houses during the march. The residents of the houses scramble to safety when the column of ants comes in. The people remove their poultry and livestock to a place of safety.

If there is a benefit for the people, it is that when they return home, there are no roaches or other insect pests in their houses! The ants eat everything that does not run or fly away.

Scientists are studying these ants to find out what causes them to migrate as they do. Scientists once thought that the army ants migrated when there was no food left in the area. Now some scientists think that the timing of the migration might be linked with the development of the eggs and the immature ants in the colony. They suspect that there is a connection between the queen’s egg production and the colony’s movements.