Morphometric analysis of the larval branchial chamber in the dragonfly Aeshna cyanea Müller (Insecta, Odonata, Anisoptera)
✍ Scribed by Stefan Kohnert; Steven F. Perry; Anke Schmitz
- Book ID
- 102370197
- Publisher
- John Wiley and Sons
- Year
- 2004
- Tongue
- English
- Weight
- 492 KB
- Volume
- 261
- Category
- Article
- ISSN
- 0362-2525
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✦ Synopsis
Abstract
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.