Trophic hierarchies illuminated via amino acid isotopic analysis

Shawn A Steffan; Yoshito Chikaraishi; David R Horton; Naohiko Ohkouchi; Merritt E Singleton; Eugene Miliczky; David B Hogg; Vincent P Jones

doi:10.1371/journal.pone.0076152

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Trophic hierarchies illuminated via amino acid isotopic analysis

Journal article

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Trophic hierarchies illuminated via amino acid isotopic analysis

Shawn A Steffan, Yoshito Chikaraishi, David R Horton, Naohiko Ohkouchi, Merritt E Singleton, Eugene Miliczky, David B Hogg and Vincent P Jones

PloS one, Vol.8(9), pp.e76152-e76152

2013

DOI: https://doi.org/10.1371/journal.pone.0076152

Handle:

https://hdl.handle.net/2376/106229

PMCID: PMC3783375

PMID: 24086703

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Abstract

Nitrogen Isotopes - analysis

Vaccinium macrocarpon - chemistry

Gas Chromatography-Mass Spectrometry

Species Specificity

Amino Acids - chemistry

Arthropods - chemistry

Amino Acids - isolation & purification

Phaseolus - chemistry

Avena - chemistry

Food Chain

Animals

Analysis of Variance

Larva - chemistry

Food web ecologists have long sought to characterize the trophic niches of animals using stable isotopic analysis. However, distilling trophic position from isotopic composition has been difficult, largely because of the variability associated with trophic discrimination factors (inter-trophic isotopic fractionation and routing). We circumvented much of this variability using compound-specific isotopic analysis (CSIA). We examined the (15)N signatures of amino acids extracted from organisms reared in pure culture at four discrete trophic levels, across two model communities. We calculated the degree of enrichment at each trophic level and found there was a consistent trophic discrimination factor (~7.6‰). The constancy of the CSIA-derived discrimination factor permitted unprecedented accuracy in the measurement of animal trophic position. Conversely, trophic position estimates generated via bulk-(15)N analysis significantly underestimated trophic position, particularly among higher-order consumers. We then examined the trophic hierarchy of a free-roaming arthropod community, revealing the highest trophic position (5.07) and longest food chain ever reported using CSIA. High accuracy in trophic position estimation brings trophic function into sharper focus, providing greater resolution to the analysis of food webs.

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Title: Trophic hierarchies illuminated via amino acid isotopic analysis
Creators: Shawn A Steffan - USDA-ARS, Madison, Wisconsin, United States of America ; Department of Entomology, University of Wisconsin, Madison, Wisconsin, United States of America
Yoshito Chikaraishi
David R Horton
Naohiko Ohkouchi
Merritt E Singleton
Eugene Miliczky
David B Hogg
Vincent P Jones
Publication Details: PloS one, Vol.8(9), pp.e76152-e76152
Academic Unit: WSU Wenatchee Tree Fruit REC
Publisher: United States
Identifiers: 99900546882101842
Language: English
Resource Type: Journal article