WASHINGTON: Exposing insects to X-ray beams a billion times more powerful than the ones that doctors use, researchers have at last settled one of the longest-running — if lesser-known — controversies in science: Bugs, it turns out, do breathe.

The discovery may seem small, and by some measures it is. The pulsing, lung-like structures that scientists were able to observe with startling clarity on high-definition X-ray videos are typically smaller than the comma in this sentence.

Among biologists, however, the evidence that insects actively inhale and exhale is nothing less than historic, closing the books on a debate that dates back to Aristotle, who grudgingly conceded that insects are alive but scoffed at the idea that they can breathe.

“We could watch the tracheal tubes in the head and thorax, which are not squishy parts of the body, really squeezing and releasing,” said Mark Westneat of Chicago’s Field Museum of Natural History, who led the study — the first to use a high- energy synchrotron beam to create a movie of a biological process. “They’re not lungs, but they’re lung-like.”

The discovery, Westneat said, could lead to new insecticides, including perhaps some that kill insects by asphyxiating them, and the X-ray technology might eventually be adapted for medical imaging in people.

Until recent decades, entomologists hewed largely to Aristotle’s view, believing that air simply drifted into and out of tiny holes in insects’ bodies. More recently it became clear that insects actively pump air through these holes by moving their bodies in particular ways.

But only now, with the creation of the first laser-like videos of living, breathing insects, is it clear that insects — like people — use muscles specifically to inhale and exhale, even when the animals are outwardly still.

Indeed, scientists said, there’s even emerging evidence that insect breathing is synchronized with the pulsing of the creatures’ circulatory systems, a level of physiological sophistication hardly anyone had imagined before.

“It looks like there’s a very complicated neurological system to keep all this coordinated,” said Thomas Miller, an insect physiologist at the University of California, Riverside. “The insect body is starting to look more and more like the vertebrate body all the time in terms of what really drives things.”

Scientists have long known that insects have holes in their bodies that lead into sinus-like pouches or tubes, bringing oxygen from the outside air to the fluids and tissues inside a bug’s body and allowing carbon dioxide to find its way back into the atmosphere. Also clear was that some insects can expand and contract their abdomens to force extra doses of air through those holes — in effect, pant.

In recent years, evidence had suggested that insects might be capable of more than that, but it’s not easy to document insect inhalation. And the one scientist who’s been the most vociferous advocate for bug breath — Karel Slama of the Czech Academy of Sciences in Prague — is such an outspoken and flamboyant character (some scientists have gone so far as to call him a “pest”) that his work has largely been ignored by other experts.

What did it take to prove that Slama was right? Nothing less than an enormous particle accelerator called a synchrotron — a circular tunnel more than a half mile around through which electrons are sent hurtling at nearly the speed of light. The synchrotron that Westneat used, part of the Energy Department’s Argonne National Laboratory in Illinois, is the most powerful X- ray machine in the Western Hemisphere. It can generate high- intensity, nearly coherent X-rays that can show structures 100 times smaller and considerably less dense than those typically visualized by medical X-rays.

The project started one day when Argonne scientist Wah-Keat Lee and a postdoctoral student got tired of using the beam to look at tiny cracks in pieces of aluminium, and decided to take aim at the head of a dead ant they found in the lab. “We looked at its head, and it was quite astounding,” Lee said. “I thought, ‘Somebody’s got to be able to do something good with this.’ “

He contacted Westneat, who jumped at the opportunity. Before long the team was taping grasshoppers, beetles, dragonflies, silverfish, flies and ants to microscope slides and creating highly detailed videos of their respiratory organs.

“We used one of the biggest scientific tools in the world to look at one of the smallest animals on Earth,” Westneat said.

A preliminary analysis of the work, published in Friday’s issue of the journal Science, suggests that insects’ muscles squeeze out about 50 per cent of the gas in their air tubes every second or so — roughly equivalent to what a person does while walking fast or going on a small jog. That’s probably a bit faster than the normal resting rate, Westneat said, given that the bugs in the experiment were probably in a panic while taped to a slide.

“We think the rates we’re seeing are similar to those in insects during exercise or flight, because they’re under some degree of stress,” he said.

It appears that insects contract their muscles to exhale, and inhalation happens effortlessly in a rebound effect. That’s the opposite of how breathing works in people, where diaphragm muscles do their work during inhalation.

“Insects never cease to amaze with their capacity to do a lot with the little that they have,” said May Berenbaum, an entomologist at the University of Illinois in Urbana-Champaign. “We were clearly mistaken to underestimate the capacity of their tracheal respiratory system.”

Now Westneat and Lee are trying to learn how insects chew their food by focusing on insect mouth parts that until now have been impossible to watch in real time. —Dawn/LAT-WP News Service (c) The Washington Post