January 27th, 2003

A Breath of Fresh Air for Insect Physiology

A surprising insect breathing mechanism similar to the way lungs work in vertebrates has been discovered by scientists from The Field Museum in Chicago and Argonne National Laboratory, using brilliant x-ray beams from the Advanced Photon Source (APS).

The results of the research were published in the Friday, January 24, 2003, issue of Science.

X-ray of air-filled pipes in the head of a beetle

Click on a link below to see frames from an x-ray video of the air-filled pipes in the head of a beetle, showing the trachea expanding with inhalation and contracting with exhalation. (Courtesy of Mark W. Westneat [The Field Museum, Chicago] and Wah-Keat Lee [Argonne National Laboratory].

Windows (AVI) Video (1.13Mb)
Quicktime (MOV) Video (11.6Mb)

High-resolution x-ray videos of living insects were obtained using 15-25-keV synchrotron x-rays from the APS. The high brightness and excellent focus of the x-ray source allows for real-time, phase-enhanced imaging in which edge enhancement of the images enables clear visualization of a living insect's anatomy and permits direct observation of changes in the volume of the insect tracheal system. X-ray videos were recorded for the anterior thorax and head regions of a variety of insects, including ground beetles (Platynus decentis), carpenter ants (Camponotus pennsylvanicus), and house crickets (Achaeta domesticus) in either top or side view.

Many species exhibited rapid cycles of tracheal compression and expansion in the head and thorax. Body movements and fluid circulation cannot account for these cycles, demonstrating a previously unknown mechanism of respiration in insects analogous to the inflation and deflation of vertebrate lungs.

Further development of the x-ray imaging technique used in this study could potentially lead to an increased understanding of the basic principles of mammalian, fish, or insect physiology. Because many of these functions have their counterparts in human physiology, this new knowledge could have important implications for human health care.

This result produced extensive media coverage, including front page stories in the Washington Post, the Chicago Tribune, prominent placement in the Chicago Sun-Times, the Sydney Morning Herald, and Der Spiegel, and an extensive array of other newspapers running the wire-service reports from UPI and AP. Worldwide Internet coverage included CNN, MSNBC, BBC, Scientific American online, Nature UK, and The Environmental News Network.

This research is supported by U.S. Department of Energy (DOE) Office of Science Contract No. W-31-109-Eng-38 and by grants ONR N000149910184 and NSF DEB- 9815614. Argonne National Laboratory is operated by The University of Chicago for the U. S. DOE. The Advanced Photon Source is funded by the U.S. DOE, Office of Science, Office of Basic Energy Sciences.

See: "Tracheal respiration in insects visualized with synchrotron x-ray imaging," M. W. Westneat,[*1] O. Betz,[1,2] R.W. Blob,[1,3] K. Fezzaa,[4] W. J. Cooper,[1,5] and W.-K. Lee[4], Science 299, 5606, pp. 558-560 (2003).

[1] Department of Zoology, Field Museum of Natural History, Chicago, IL 60605.
[2] Department of Zoology, University of Kiel, Germany
[3] Department of Biological Sciences, Clemson University, Clemson, SC 29634
[4] Experimental Facilities Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL.
[5] Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637.
*To whom correspondence should be addressed. Email: mwestneat@fieldmuseum.org