A Test of DNA Barcoding (a.k.a. DNA Taxonomy) based on near complete species level sampling of Australian diving beetles
Zusammenfassung der Projektergebnisse
Demand for scientific biodiversity data is increasing, but taxonomic expertise is limited or not available. DNA sequencing is a potential a remedy to overcome the “taxonomic impediment”. Mitochondrial DNA is most commonly used, for example for species identification, a technique coined “DNA barcoding”. The project presents the first arthropod study based on a near-complete species level sampling of a focal group, here from the entire Australian region. We ask how reliably mitochondrial DNA [= mtDNA] data capture the species diversity when many sister species pairs are included (phylogenetic subsampling). Then, we contrast phylogenetic subsampling with the hithero more commonly applied regional subsampling, where sister species are not necessarily captured. Our study organisms are Australian diving beetles (Dytiscidae), for which we command extensive taxonomic expertise and which we collected across this entire zoogeographical region. We have collected, sequenced (cytochrome c oxidase 1) and morphologically sorted around 80% of the species of the Australian diving beetle fauna comprising near-complete species level coverage of several endemic radiations. The analyses so far revealed clear mtDNA clustering for most recognized species, and we identified more than 30 new species, some of them cryptic which are described in several taxonomic revisions. However, this work also reveals that some, if not all radiations contain recent bursts of diversification where up to 5 distinct morphospecies per radiation do group in one mixed haplotype cluster. Here, we suggest to present state-of-the art taxonomic revisions of poorly known Australian genera to translate the outcomes of the mtDNA sequencing campaign into a formal classification, thus providing scientific names for all the species recognized now, and to evaluate nDNA [nuclear encoded DNA] markers in cases where mtDNA failed to retrieve morphospecies. We sequenced 800 bp from the 3’ end of cox1 for 1141 individuals of 260 Australian species (78% species coverage). For the highly endemic genera of the tribe Hydroporini (10 genera, 150 species), we cover 125 species (83%). We use clustering with thresholds of 1–10% and GMYC [= generalized mixed Yule-coalescent] analysis for species richness estimation. Performance metrics were taxonomic accuracy and agreement of the morphological and molecular species richness estimation. Clustering (at 3%) and GMYC reliably estimate species diversity for single or multiple geographic regions, and for larger clades, error <10%, thus outperforming parataxonomy. The error was higher for individual or genera, up to 45% where very recent species form paraphyletic clusters. Taxonomic accuracy is always much lower, with an error >20%, but taxonomic accuracy is highly idiosyncratic on genus level (error 0–70%). We suggest that cox1 sequence data are a powerful tool in large scale species richness estimation, with great potential for ecology, ß-diversity studies and conservation priority setting. After this project, Australian diving beetle taxonomy will be clarified on the highest level possible, with extensive DNA, tissue and voucher collections created and deposited in major museums.
Projektbezogene Publikationen (Auswahl)
- (2009): Darwins Traum und die Evolution australischer Schwimmkäfer – Vortrag zum Entomologentag der Münchner Entomologischen Gesellschaft am 13. März 2009.- Nachrichtenblatt bayerischer Entomologen 58 (3/4): 97-10
Hendrich, L.
- (2009): Kakadudessus tomweiri, a new genus and species of diving beetle from tropical northern Australia, based on molecular, phylogenetic and morphological data (Coleoptera, Dytiscidae, Bidessini).- Zootaxa 2134: 49-59
Hendrich, L. & M. Balke
- (2009): New Guinea highland origin of a widespread arthropod supertramp.- Proceedings of the Royal Society London (Ser. B) 276: 2359-2367
Balke, M., Ribera, I., Hendrich, L., Miller, M., Sagata, K., Posman, A., Vogler, A.P. & Meier, R.
- (2009): Taxonomic revision of the Australian predaceous water beetle genus Carabhydrus WATTS, 1978 (Coleoptera: Dytiscidae, Hydroporinae).- Zootaxa 2048: 1-30
Hendrich, L. & C.H.S. Watts
- (2009): The epigean Australasian species of Neobidessodes gen.n. diving beetles–a revision integrating morphology, cybertaxonomy, DNA taxonomy and phylogeny (Coleoptera: Dytiscidae, Bidessini).-Zootaxa 2288: 1-41
Hendrich, L., Hawlitschek, O. & Balke, M.
- (2010): Dytiscidae: Annotated checklist of the Bidessini, Hydrovatini, Hyphydrini, Laccophilinae and Dytiscinae (Coleoptera), pp. 171-194.- In: Jäch, M. A. & Balke, M. (eds.): Water Beetles of New Caledonia (part 1).- Monographs on Coleoptera 3: IV+449 pp.
Hendrich, L., Balke, M. & G. Wewalka
- (2010): Dytiscidae: Hydroporini (Coleoptera), pp. 149-162.- In: Jäch, M. A. & Balke, M. (eds.): Water Beetles of New Caledonia (part 1).- Monographs on Coleoptera 3: IV+449 pp.
Hendrich, L., Balke, M. & G. Wewalka
- (2010): Dytiscidae: Taxonomic revision of New Caledonian Copelatini (Coleoptera: Dytiscidae), pp. 45-128.- In: Jäch, M. A. & Balke, M. (eds.): Water Beetles of New Caledonia (part 1).- Monographs on Coleoptera 3: IV+449 pp.
Wewalka, G., Balke, M. & L. Hendrich
