Validation of the doubly labeled water method under low and high humidity to estimate metabolic rate and water flux in a tropical snake (Boiga irregularis)

• Published in: Journal of applied physiology (1985) Vol. 95; no. 1; pp. 184 - 191
• Main Authors: Anderson, Nancy L, Hetherington, Thomas E, Williams, Joseph B
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Physiological Soc 01.07.2003; American Physiological Society
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Animals; Autoecology; Biological and medical sciences; Body Water - metabolism; Body Weight - physiology; Calorimetry, Indirect; Carbon Dioxide - metabolism; Dehydration - metabolism; Deuterium; Environment; Fundamental and applied biological sciences. Psychology; Humidity; Isotope Labeling; Kinetics; Metabolism; Metabolism - physiology; Oxygen Radioisotopes; Reptilia. Amphibia; Respiratory system; Snakes; Snakes - metabolism; Temperature; Vertebrata; Water; Water Loss, Insensible - physiology; Water; Validation; Carbon dioxide; Double labelling; total evaporative water loss; Environmental factor; Boiga irregularis; Evaporation; Metabolism; Ophidia; Vertebrata; carbon dioxide production; Humidity; Reptilia; Skin; Gas exchange; Measurement method; Respiration
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00692.2002

Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, Ohio 43210 Submitted 29 July 2002 ; accepted in final form 26 March 2003 This study uses indirect calorimetry to assess the effects of humidity on the accuracy of the doubly labeled water (DLW) technique to predict metabolic rate and water flux in brown treesnakes ( Boiga irregularis ). The DLW technique accurately predicted total water efflux in brown treesnakes under low-humidity conditions and found that the total number of water molecules exchanged with the environment under humid conditions was not significantly different than maximum net total evaporative water loss under low humidity conditions plus fecal water loss. Because of changes of total body water of >12%, the DLW technique overestimated metabolic rate by a factor of 2.2 under low-humidity conditions. Under high-humidity conditions, the DLW technique overestimated metabolic rate in brown treesnakes by a factor of 4.6. Researchers using the DLW technique in humid or moist environments should be cautious because this study indicates that DLW estimates of metabolic rate may be inflated when large amounts of water vapor are exchanged through the skin or respiratory passages. total evaporative water loss; carbon dioxide production Address for reprint requests and other correspondence: N. L. Anderson, Lindsay Wildlife Museum, 1931 First Ave., Walnut Creek, CA 94597 (E-mail: nanderson{at}wildlife-museum.org ).