A DNA Barcode Inventory of Austrian Dragonfly and Damselfly (Insecta: Odonata) Species

Dragonflies and damselflies are important indicator species for quality and health of (semi-)aquatic habitats. Hitherto, 78 species of Odonata have been reported for Austria. Ecological data, Red List assessments, and a dragonfly association index exist, but population- and species-level genetic data are largely lacking. In this study, we establish a comprehensive reference DNA barcode library for Austrian dragonflies and damselflies based on the standard barcoding marker <i>COI</i>. Because of the increasing significance of environmental DNA (eDNA) analyses, we also sequenced a segment of the mitochondrial <i>16S</i> rRNA gene, a marker often used in eDNA metabarcoding approaches. In total, we provide 786 new <i>COI</i> barcode sequences and 867 new <i>16S</i> sequences for future applications. Sequencing success was >90 percent for both markers. Identification success was similar for both markers and exceeded 90 percent. Difficulties were only encountered in the genera <i>Anax</i> Leach, 1815, <i>Chalcolestes</i> Kennedy, 1920, <i>Coenagrion</i> Kirby, 1890 and <i>Somatochlora</i> Selys, 1871, with low interspecific genetic distances and, consequently, BIN (barcode index number) sharing. In <i>Anax</i>, however, individual sequences clustered together in species-specific groups in the <i>COI</i> tree. Irrespective of these challenges, the results suggest that both markers perform well within most odonate families in terms of sequencing success and species identification and can be used for reliably delimiting Austrian species, monitoring, and eDNA approaches.