Insects squeeze to breathe

Expand and compress: An insect works the air

Scientists have used X-ray video to study how insects breathe.

Unlike humans, which have lungs and blood to push oxygen to vital organs, an insect sends air directly around its body via a set of internal pipes running from holes in its external skeleton.

This is the first time anyone has applied this technology to study living insects

Wah-Keat Lee

Although these tubes have long been known about, the X-ray pictures have revealed impressive new details of their workings.

The researchers were able to see how the pipes - called tracheae - can be squeezed by the insect to maintain a constant and high throughput of air.

Some species

While resting, an insect can exchange up to half the air inside its main tubes every second. This is equivalent to how hard a person would breathe while doing moderate exercise.

This wood beetle was found to use tracheal compression - but not all insects do

The scientists, led by Mark Westneat, from The Field Museum in Chicago, US, said not all insect species they studied where able to use tracheal compression - those that were included some beetles, crickets, ants, butterflies, cockroaches, and dragonflies.

Up until now, it has not been possible to see movement inside living insects.

The research team got around this by using a synchrotron - a large, circular, particle accelerator.

Eating insects

By pushing electrons to near light-speed, the machine is able to generate X-rays that are more than one billion times as intense as a conventional X-ray source.

With this radiation, structures that once baffled researchers can now be probed in detail.

"This is the first time anyone has applied this technology to study living insects," said co-author Wah-Keat Lee, a physicist at the Argonne National Laboratory, the site of the synchrotron.

Westneat added: "What we've done with this work is create a window into these tiny little animals that nobody's ever seen inside before."

The researchers, who report their work in the journal Science, say they plan to investigate how insects eat using the new technique.