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Morphometric analysis of the larval branchial chamber in the dragonfly Aeshna cyanea Müller (Insecta, Odonata, Anisoptera)
Author(s) -
Kohnert Stefan,
Perry Steven F.,
Schmitz Anke
Publication year - 2004
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.10230
Subject(s) - gill , biology , anisoptera , odonata , dragonfly , larva , anatomy , cuticle (hair) , zoology , ecology , fish <actinopterygii> , fishery
The aquatic larvae of anisopteran dragonflies possess tracheal gills located in the rectum. Using stereological methods, we estimated the morphometric diffusing capacity for oxygen (D MO2 ) across the gill epithelium, i.e., from rectal water to the gill tracheoles, in the larvae of Aeshna cyanea . A 271‐mg larva has a total branchial surface area of ∼12 cm 2 . Tracheoles make up 6% of the epithelial volume of the gills; the harmonic mean thickness of the water–tracheolar diffusion barrier is 0.27 μm and consists mainly of cuticle. The calculated D MO2 is 23.0 μl min ‐1 g ‐1 kPa ‐1 , which, using published values for oxygen consumption in a similar species, would result in a mean driving pressure of 0.2 kPa at rest and 1.3 kPa during activity. Since these driving pressures are similar to those reported for other arthropods, we conclude that the D MO2 of the gill is not rate‐limiting for aerobic metabolism in Aeshna cyanea larvae. J Morphol. 261:81–91, 2004. © 2004 Wiley‐Liss, Inc.