X-Ray Reveals How Insects Breathe

AP Wire Service

WASHINGTON – Bugs don’t have lungs, so how do they breathe? Maybe more efficiently than people, according to the first close-up view of insects forcing air in and out of tiny oxygen pipes.

It took one of the world’s strongest X-ray beams — a view hundreds of times more detailed than today’s most sophisticated medical scans can provide — for scientists at The Field Museum in Chicago and Argonne National Laboratory to videotape how beetles, crickets and ants breathe.

“They are really pumping some gas,” said lead researcher Mark Westneat, the museum’s associate curator of zoology.

While resting, the insects exchanged up to half the air inside their main oxygen tubes every second — equivalent to how hard a person breathes while doing moderate exercise, the researchers report in Friday’s edition of the journal Science.

These tubes, called tracheae, connect to tiny air holes in the insect’s outer coating. For decades, scientists thought air just passively oozed into those holes. Then researchers spotted some tiny air sacs near insects’ wings, legs and abdomens that they might use to help pump air inside.

But the rest of the insect body is rigid, so no one thought much more air pumping could go on. Instead, Westneat discovered insects somehow squeeze the air tubes throughout their bodies to suck air in and out, much as lungs do.

“It’s an important discovery,” said insect researcher Robert Dudley of the University of California, Berkeley — and equally important is the technology that allowed it.

The machine is called a synchrotron, a large particle accelerator that generates the world’s most intense X-rays. There are only a few in existence, and they’ve largely been used in chemistry, Westneat said.

Then Argonne physicist Wah-Keat Lee, hunting new uses, put a dead ant inside his synchrotron and saw spectacularly detailed images of its organs. He teamed with Westneat to put living insects in the machine. They were bombarded with mega doses of radiation, so experiments with more advanced animals aren’t likely.

Still, Westneat said, “What we’ve done with this work is created a window into these tiny little animals that nobody’s ever seen inside before.”

Stay tuned: Future research ranges from how bugs eat to how beetles’ eight-to-10 hearts function.