[Odonata-l] Oxygen and insect gigantism

[Roy J. Beckemeyer]

An interesting paper on this subject was published last year in PNAS.  It is available in pdf form at: 
http://www.pnas.org/content/104/32/13198.full.pdf+html
Kaiser et al found evidence supporting oxygen limitation as a factor in insect gigantism because of increases of tracheal investment with size observed in extant beetles.  Cross-sectional area of the tracheae in the legs increased with mass to the 1.07 power while cross sectional area of the leg varied with mass to the 0.77 power - i.e. tracheal area would become limited by size limits of the leg structure as the beetles got bigger.
Anyway, I believe folks who have commented on this thread thus far might like to read the paper.  PNAS papers are pretty much all available for free at their web site.


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