The problem of omnivory: A synthesis on omnivory and DNA metabarcoding

A - Papers appearing in refereed journals

Tercel, M. P. T. G., Symondson, W. O. C. and Cuff, J. P. 2021. The problem of omnivory: A synthesis on omnivory and DNA metabarcoding. Molecular Ecology.

AuthorsTercel, M. P. T. G., Symondson, W. O. C. and Cuff, J. P.

Dietary analysis using DNA metabarcoding is a powerful tool that is increasingly being used to further our knowledge of trophic interactions in highly complex food webs but is not without limitations. Omnivores, the most generalist of consumers, pose unique challenges when using such methods. Here, we provide the rationale to understand the problems associated with analysing the complex diets of omnivores. By reviewing existing metabarcoding studies of omnivorous diet, and constructing hypothetical scenarios arising from each, we outline that great caution is required when interpreting sequencing data in such cases. In essence, the problems of accidental consumption and secondary ingestion are significant sources of error when investigating omnivorous diets. The integration of multiple high throughput sequencing markers increases the taxonomic breadth of taxa detected but we reveal how some detections may be misleading. Disentangling which taxa have been deliberately or accidentally consumed by the focal omnivore is challenging and can falsely emphasise those that were not intentionally consumed, obscuring biologically meaningful interactions. Although we suggest ways to disentangle these issues, we urge that the results of such analyses should be interpreted with caution and all possible scenarios for the presence of biota within omnivores given due consideration.

KeywordsDiet analysis ; Trophic interactions; Secondary predation ; Multiple markers ; High‐throughput sequencing ; Generalist
Year of Publication2021
JournalMolecular Ecology
Digital Object Identifier (DOI)
Open accessPublished as ‘gold’ (paid) open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeBB/M009122/1
Publisher's version
Output statusPublished
Publication dates
Online08 Apr 2021
Publication process dates
Accepted27 Mar 2021

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