This system is much more efficient than the system that vertebrates evolved. Insects deliver much greater volumes of oxygen, in proportion to their size, than do mammals. They also deliver oxygen directly to the tissues, while vertebrates dissolve oxygen in blood, transport it to tissues, and then reconvert the oxygen to usable form.
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Because insects take in oxygen through spiracles which they open and close as needed, and because they can take in a large store of oxygen, they can live a long time without breathing by closing their spiracles and curbing their activity.
“Insects are able to survive hypoxic environments,?explained Kirkton, the symposium chairman. “They can shut down and survive for hours or days. They have a low metabolic rate and can close their spiracles. If you compare Lance Armstrong, the bee and the hummingbird, the bee is the champion of oxygen delivery,?he said. But at the same time, insects can survive low levels of oxygen for a comparatively long time.
Researchers have been interested in the insect tracheal respiratory system since 1911 when August Krogh researched moths and grasshoppers. Krogh’s interest in oxygen delivery led him later to study blood perfusion in mammalian capillaries, for which he was awarded the Nobel Prize in 1920. But the advent of synchrotron x-rays, an advanced form of x-ray scan, has recently allowed scientists to learn much more about how insects breathe. The new imaging technology allows scientists to observe the respiration of live bugs.
This advance in technology also comes at a time when physiologists are learning more about the genes that control breathing. When physiologists gather at the symposium, they will assess these new developments and consider a roadmap for future research, said Kirkton.
The symposium, which is also sponsored by the London-based Journal of Physiology, will feature the following s
Source:American Physiological Society