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Tales from the anthill

Insect ecology

Lesson Plan

March 15, 2002 Posted: 11:52 AM EST (1652 GMT)
Leaf-cutter ants  

By Michael McManus
CNN Student News

WASHINGTON (CNN) -- "There is very little humans have invented that ants or other insects hadn't already thought of millions of years before humans were around."

It's the first thing out of Dr. Ted Schultz's mouth as he introduces himself.

Schultz has decided to dedicate his life to understanding the complex behavior of ants. You're probably thinking, "Complex behavior? Ants?" Schultz has some great tales from the anthill that just might change your mind.

Insect ecology is the study of how insects interact with their environments and with other organisms in their environments.

Schultz studies fungus-growing ants, which depend entirely on a species of fungi in order to survive. "If their crops fail, the entire colony dies, they have no other way of existing. Practicing this agriculture is the only thing they know."

CNN Student News' Michael McManus looks into insect ecology

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Like humans, fungus-growing ants are true farmers and the survival of the colony depends on the food they grow. Anywhere from a few hundred to over five million ants can inhabit any given colony at one time, and every single one has a job to do.

The gardens consist of a special fungus the ants eat. Certain ants within the colony weed the garden, some dispose of waste, some excavate new underground chambers, and still others forage outside the nest for new compost on which their gardens grow.

Just as humans protect their homes and families, the largest and strongest "soldier" ants attack intruders, including army ants, anteaters, and even human scientists.

Schultz describes the reaction to an intruder. "One or more worker ants will react by releasing alarm pheromones. Soldier ants within the colony will start moving toward the source of this pheromone, and attack anything that's not supposed to be there."

A pheromone is an airborne molecule -- an odor -- and a soldier ant's reaction to "smelling" this alarm signal is rapid and deadly.

Soldier ants arrive almost immediately and begin biting intruders in order to protect the colony. The nest is the ants' home and the colony is their family, and they make that very clear.

Although ants can be savage in their response to enemies, they can be gentle to their friends. This is especially true when it comes to caring for their pets. That's right, ants have pets.

Some ants care for aphids, a kind of insect that feeds on plants. Ants tend to these slow-moving creatures by protecting them from parasites and predators.

Dr. Ted Schultz  

Then, the ants "milk" these so-called pets for honeydew, a sweet liquid produced by the aphids just for the ants.

Both creatures need something from the other, and the exchange of services works out well. The ants provide protection; the aphids return the favor with nutrition for the ants.

Looking through the clear plastic into Schultz's laboratory "ant farm" of fungus-growing ants, you can't take your eyes off the city within. The garden looks like a coral reef, a fluffy, white, spongy mass interlaced with tunnels and passages.

It's fascinating to watch the efficiency with which the ants work. Each ant has a particular job that helps the whole colony survive. Cooperation is key to the ants' survival.

Michael McManus is an anchor for CNN Student News.

• U.S. imports fire ant enemies
November 30, 1999

• Dr. Ted Schultz: Research Entomologist
• Department of Entomology, Smithsonian National Museum of Natural History
• Department of Entomology: Ant Database
• The Ant Colony Cycle

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Updated September 21, 2002

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