Breathing bugs

Insects have been assumed to breathe through a system of tracheal tubes (considered passive air channels), with gaseous exchange being driven by body movements or hemolymph circulation. However, the exact mechanisms involved in insect respiration are difficult to visualize and have therefore been difficult to characterize. In the January 24 Science, Mark W. Westneat and colleagues at the Field Museum of Natural History, Chicago, USA, show that insects have an active mechanical mechanism of respiration similar to the inflation and deflation of vertebrate lungs (Science, 299:558-560, January 24, 2003).

Westneat et al., used a synchrotron beam to obtain x-ray videos of living, breathing insects. They observed that beetles, crickets, and ants had rapid cycles of tracheal compression and expansion in the head and thorax similar to animal respiratory movements. These movements could not be explained by body movements or hemolymph circulation and suggest a previously unknown active mechanism of respiration.

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