Pulling Ant Castles From the Ground

What's truly amazing is each ant has its own chores to do, and it does so without supervision.

"There's no boss in the ant world," Tschinkel says.

The most basic division of labor is based on age. The younger ants take care of the newly hatched ants. Middle aged ants do most of the nesting chores. And only the oldest ants venture out of the safety of the nest to forage for food.

"They are only foraging toward the end of their lives," he says. "That makes sense because foraging is by far the most dangerous activity.

"It's the opposite of what we do. We take our youngest men, the ones with the highest reproductive future, and send them off to war. Ants don't do that."

The foraging process involves the area of science that got Tschinkel into ants in the first place — chemical communication.

When a foraging ant finds a food source, it literally leaves a chemical trail for other members of the nest to follow when they head out to harvest the new resource. Nearly all species of ants have that capability, but it developed in different ways.

"We know that because different ants use different glands" to produce the chemicals, Tschinkel says.

Chemical Communication

Some excrete chemicals, leaving an odor for their colleagues to follow, and some apparently have sneaker feet, "literally leaving a footprint trail" that other ants can follow, he says.

"There's dozens of variations on this basic theme," but nearly all ants have figured out a way to communicate chemically with their co-workers, he added.

Some ants are even more resourceful. There's a symbiotic relationship between aphids and ants. As any gardener knows, aphids dine on plants, but plant tissue contains much less nitrogen than animals need.

"It's mostly sugar," Tschinkel says. So aphids excrete the excess sugar in order to concentrate the nitrogen. The excreted sugar, called "honeydew," is prized by a wide range of insects, including ants.

As a result, some ants become aphid ranchers, herding and tending their flocks of aphids so they can have a steady supply of honeydew. The ants, in turn, protect the aphids from parasites.

"Some are so dependent on each other that the ants actually take the aphids underground in the winter," assuring their survival, Tschinkel says.

Once underground, they enter a castle that is so intricate and so functional that it is a marvel to behold.

Lee Dye’s column appears weekly on ABCNEWS.com. A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.

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