QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online November 19, 2004
Journal of Experimental Biology 207, 4463-4471 (2004)
Published by The Company of Biologists 2004
doi: 10.1242/jeb.01284

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lighton, J. R. B. Articles by Holway, D. A. Search for Related Content PubMed PubMed Citation Articles by Lighton, J. R. B. Articles by Holway, D. A.

The hyperoxic switch: assessing respiratory water loss rates in tracheate arthropods with continuous gas exchange

John R. B. Lighton^1,*, Pablo E. Schilman² and David A. Holway²

¹ University of Nevada at Las Vegas, Department of Biology, University of Nevada at Las Vegas, 4505 Maryland Parkway, NV 89154-4004 USA
² Section of Ecology, Behavior and Evolution, Division of Biological Sciences, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0116 USA

^* Author for correspondence (e-mail: john{at}johnlighton.org)

Accepted 13 September 2004

Partitioning the relative contributions of cuticular and respiratory water loss in a tracheate arthropod is relatively easy if it undergoes discontinuous gas exchange cycles or DGCs, leaving its rate of cuticular water loss in primary evidence while its spiracles are closed. Many arthropods are not so obliging and emit CO₂ continuously, making cuticular and respiratory water losses difficult or impossible to partition. We report here that by switching ambient air from 21 to 100% O₂, marked spiracular constriction takes place, causing a transient but substantial – up to 90% – reduction in CO₂ output. A reduction in water loss rate occurs at the same time. Using this approach, we investigated respiratory water loss in Drosophila melanogaster and in two ant species, Forelius mccooki and Pogonomyrmex californicus. Our results – respiratory water loss estimates of 23%, 7.6% and 5.6% of total water loss rates, respectively – are reasonable in light of literature estimates, and suggest that the `hyperoxic switch' may allow straightforward estimation of respiratory water loss rates in arthropods lacking discontinuous gas exchange. In P. californicus, which we were able to measure with and without a DGC, presence or absence of a DGC did not affect respiratory vs total water loss rates.

Key words: Drosophila melanogaster, gas exchange, water loss, cuticular permeability, Pogonomyrmex californicus, Forelius mccooki

This article has been cited by other articles:

				J. R. B. Lighton and R. J. Turner The hygric hypothesis does not hold water: abolition of discontinuous gas exchange cycles does not affect water loss in the ant Camponotus vicinus J. Exp. Biol., February 15, 2008; 211(4): 563 - 567. [Abstract] [Full Text] [PDF]

				C. R. White, T. M. Blackburn, J. S. Terblanche, E. Marais, M. Gibernau, and S. L. Chown Evolutionary responses of discontinuous gas exchange in insects PNAS, May 15, 2007; 104(20): 8357 - 8361. [Abstract] [Full Text] [PDF]

				E. M. Gray and T. J. Bradley Evidence from mosquitoes suggests that cyclic gas exchange and discontinuous gas exchange are two manifestations of a single respiratory pattern J. Exp. Biol., May 1, 2006; 209(9): 1603 - 1611. [Abstract] [Full Text] [PDF]

				J. R. B. Lighton and E. A. Ottesen To DGC or not to DGC: oxygen guarding in the termite Zootermopsis nevadensis (Isoptera: Termopsidae) J. Exp. Biol., December 15, 2005; 208(24): 4671 - 4678. [Abstract] [Full Text] [PDF]