X-ray shows how beetles breathe

Sunday, February 2, 2003

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 medical scans can provide -- for scientists at The Field Museum in Chicago and Argonne National Laboratory to videotape how beetles breathe.

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 reported in 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. Instead, scientists discovered insects somehow squeeze the air tubes throughout their bodies to suck air in and out, much as lungs do.

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