Is qualitative and quantitative metabarcoding of dung fauna biodiversity feasible?
In biodiversity assessments, especially of small‐bodied organisms for which taxonomic expertise is lacking, identification by genetic barcoding may be a cost‐effective and efficient alternative to traditional identification of species by morphology, ecology and behavior. Here we test the feasibility and accuracy of such an approach using dung insects of practical relevance in ecotoxicological assessments of veterinary pharmaceutical residues in the environment. We produced eight known mixtures that varied in absolute and relative composition of small and large‐bodied species to see whether mitochondrial Cytochrome c Oxidase subunit 1 barcoding picks up all species qualitatively and quantitatively. As demonstrated before in other contexts, such metabarcoding of large numbers of dung insect specimens is principally possible using next‐generation‐sequencing. We recovered most species in a sample (low type I error), at minimum permitting analysis of species richness. We obtained even quantitative responses reflecting the body size of the species, although the number of specimens was not well detected. The latter is problematic when calculating diversity indices. Nevertheless, the method yielded too many closely related false positives (type II error), thus generally overestimating species diversity and richness. These errors can be reduced by refining methods and data filtering, however requiring bioinformatics expertise often unavailable where such research is carried out. Identification by barcoding foremost hinges on a good reference database, which does not yet exist for dung organisms but would be worth developing for practical applications. This article is protected by copyright. All rights reserved