Ants on Stilts Help Show Bugs Have "Pedometers"

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In fact, ants often lose leg segments with age, Wittlinger says.

"The desert floor is very hot indeed, up to 70 degrees Celsius [158 degrees Fahrenheit]," he said, "and the tissue thus dies off due to heat stress, desiccates, and just breaks off. You can often see old ants in the desert walking on their last legs, literally."

In fact, the scientists say, it was watching such aged ants that gave them the idea for the experiment.

The study, to be published in tomorrow's issue of the journal Science, found that changing the ants' leg lengths did indeed scramble their internal pedometers.

For the ants on stilts, each step now covered more distance than they were used to. They overshot the nest, running an average of more than 50 percent farther than they should have.

Those with shortened legs undershot by nearly as much.

Interestingly, the ants quickly adjusted to their new leg lengths.

After the initial experiment, the ants were promptly returned to their nest.

The next day the modified ants were allowed to engage in normal foraging, and they returned to the nest as well as the "normal" ants.

(Related wallpaper: Borneo ant on a plant.)

Cool Finding

Robert Johnson, an ecologist who studies ants at Arizona State University, considers the finding "cool."

"It's like riding your bike and [having someone] change the size of the wheels without telling you," he said.

If you then tried to rely on your odometer, you, like the ants, wouldn't wind up where you expected.

How exactly the ants calculate the distance they've traveled remains a mystery, though Wolf's team doubts that the insects have the brainpower to literally count steps.

More likely, the scientists say, they're somehow doing it intuitively.

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