WASHINGTON -- Experiments on ladybugs, crickets and ants have for the first time shown how insects breathe -- without lungs, but in some ways similar to humans' pulmonary system, according to research published Thursday.

Insects have a system of internal tubes called tracheae that exchange oxygen through a slow, passive mechanism, and using rapid compression and expansion of the head and thorax, according to the latest edition of the journal****Science.***** Although not all insects studied by the Field Museum of Chicago have this mechanism, butterflies, cockroaches, beetles and dragonflies are among those that also do, mirroring the human respiratory system.

"The discovery of this fundamental aspect of respiratory biology for insects could revolutionize the field of insect physiology," said Mark Westneat, associate curator of zoology at the Field Museum, and a lead author in the study.

Until now, no one had managed to see insects breathing.

Researchers overcame this obstacle by using a synchrotron -- or particle accelerator -- which produces one of the most powerful X-ray beams in the world, used to take X-ray videos of live animals.

In insects that apparently use the system, at least half of the air in the main tracheal airways was replaced each second -- equivalent to that of a person undergoing moderate physical activity.

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