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The use of tunable diode laser absorption spectroscopy for rapid measurements of the δ 13 C of animal breath for physiological and ecological studies
Author(s) -
Engel Sophia,
Lease Hilary M.,
McDowell Nate G.,
Corbett Alyssa H.,
Wolf Blair O.
Publication year - 2009
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.4004
Subject(s) - chemistry , photosynthesis , absorption (acoustics) , crassulacean acid metabolism , herbivore , breath gas analysis , absorption spectroscopy , environmental chemistry , analytical chemistry (journal) , ecology , biochemistry , chromatography , physics , acoustics , biology , quantum mechanics
In this study we introduce the use of tunable diode laser absorption spectroscopy (TDLAS) as a technique for making measurements of the δ 13 C of animal ‘breath’ in near real time. The carbon isotope ratios ( δ 13 C) of breath CO 2 trace the carbon source of the materials being metabolized, which can provide insight into the use of specific food resources, e.g. those derived from plants using C 3 versus C 4 or CAM photosynthetic pathways. For physiological studies, labeled substrates and breath analyses provide direct evidence of specific physiological (e.g. fermentative digestion) or enzymatic (e.g. sucrase activity) processes. Although potentially very informative, this approach has rarely been taken in animal physiological or ecological research. In this study we quantify the utilization of different plant resources (photosynthetic types – C 3 or C 4 ) in arthropod herbivores by measuring the δ 13 C of their ‘breath’ and comparing it with bulk tissue values. We show that breath δ 13 C values are highly correlated with bulk tissues and for insect herbivores reflect their dietary guild, in our case C 3 ‐specialists, C 4 ‐specialists, or generalists. TDLAS has a number of advantages that will make it an important tool for physiologists, ecologists and behaviorists: it is non‐invasive, fast, very sensitive, accurate, works on animals of a wide range of body sizes, per‐sample costs are small, and it is potentially field‐deployable. Copyright © 2009 John Wiley & Sons, Ltd.