How do ants differ from other social insects?


Bees, wasps, and ants belong to the order Hymenoptera. Bees feed on flowers; wasps hunt other insects; ants "feed on a whole variety of things," from flowers to dead animals, says University of Georgia entomologist Ken Ross. Morphology also differs: worker bees and wasps with different jobs are all the same size, but the sizes of worker ants vary according to their role in the colony.

What are some differences among ants?

With more than 11,000 known species, no two are alike. "There is unbelievable variation in the way they can make a living," says Ross. Slave-maker ants raid other colonies and take their workers as prisoners. Leaf-cutter ants chew leaves into mulch, which grows an edible fungus. A worker caste of honey-pot ants called repletes swell into tiny balls to store food collected by foragers. Army ants move in columns, eating...

How do ants communicate?

Ants use antennae to smell pheromone signals from their cohorts. "Ants have, by far, the most advanced form of chemical communication found in any organism," says Harvard's Edward O. Wilson. Ants distinguish alien species from their own, and can differentiate between workers from their colony and those from another colony of their species.

How do ants and their colonies differ in size?

Wilson says that 1015 ants are alive at any one time and range in size from about 5 mm to 25 mm, like Australia's bull ants. The smallest colonies live inside acorns and have only tens or hundreds of workers, but species like the African driver ants can have as many as 20 million workers in a single nomadic colony.

What is known about their social behavior?

Entomologists are examining "the genetics of social behavior," says Ross. In 2002, his research group identified a single gene in the South American fire ant that controls behaviors necessary for forming colonies.1 Wilson says that instead of acting to serve their individual interests, ants act for the best of the colony.

- Maria W. Anderson

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