Lighton 9603873 Insects are among the most important animal on Earth, yet we know very little about their oxygen uptake and carbon dioxide release mechanisms (external respiration or `breathing'). Many insects breathe discontinuously, in discrete events or "bursts" spaced several to tens of minutes apart. The detailed nature of this pattern which is called a Discontinuous Gas-exchange Cycle or DGC is being explored in my laboratory, using several diverse ant species, other insects, and tracheate arachnids as model organisms. For a small animal in an arid environment, breathing as model organisms. For a small animal in an arid environment, breathing can be a major avenue of water loss yet must continue if the animal is to live. We are investigating the internal physical and chemical factors which control the timing of the DGC; how the DGC functions in conserving water reserves; and the environmental factors driving the evolution and maintenance of the DGC. The result will be the first in-depth, comprehensive and quantitative account of discontinuous external respiration phenomena; including their control, implications for body water conservation, and independent evolution in several very different tracheate arthropods. Our findings may also increase our understanding of potential physiological targets for the control of medically and economically important arthropods.
