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battling ants.

Ant Wars!

I was surprised when I walked down my driveway and found this dark patch of fuzzy litle worm-like creatures. At first I thought I was observing newly hatched caterpillars, but as I looked closer I realized each little caterpillar was actually two ants grapelling head to head. It was an ant war!

These ants were pavement ants (Tetramorium caespitum) . They often build nests under rocks and pavement so they are a common ant to find in your driveway. These ants, although they live all over the eastern United States, are an exotic species introduced from Europe. They feed on a number of different things including aphid honeydew, seeds, and live and dead insects.

Usually we think of ants as ferociously protecting their nests from other species, but in this case two different colonies of the same species are fighting. Ant wars like this one usually result from territory battles. Each ant colony protects an area around the colony that it uses for food foraging. Ants use patrolling workers that release unique colony pheremones to mark their territory. As the population of workers in the colony grows more food than the original area can supply is sometimes needed. If the ants enter an area defended by a different colony battles result.

When two ants from different colonies meet, they will face each other in a posture intended to frighten the other away. They release pheremones that other ants in their colony will recognize and move toward and often a line of ants facing each other forms. If neither ant backs down the the ants fight each other by locking jaws and pushing forward or by flipping their opponents and stinging them. In territorial battles, usually one colony will back down before a majority of worker ants are killed. Ants are social insects where a large number of sterile workers protect one reproductive queen. In small colonies there are few if any specialized "soldier ants" that often occur in larger more complex ant societies so each worker must do a variety of tasks and so is very important to the colony's survival. If too many ants die, there will not be enough food collected and the colony will die. Because of this, ant wars in small colonies like this rarely result in the complete destruction of a colony.

More info on Pavement ants

Here is a link to an ant war experiment by Paul Johnson at the University of New Hampshire that you can try at home or at school!

Contributed by Vicki Medland of the Cofrin Center for Biodiversity

© 2001-2004 The Cofrin Center for Biodiversity and the University of Wisconsin Green Bay, All Rights Reserved
Last updated on April 15, 2014