Non-destructive collection and metabarcoding of arthropod environmental DNA remained on a terrestrial plant

For the conservation and community ecology of arthropods and pest controls on terrestrial plants, survey of arthropods is a crucial step. However, efficient surveys are hindered by challenges in collecting small arthropods, and identifying the species. Environmental DNA (eDNA)-based techniques, such as eDNA metabarcording, help overcome these difficulties in aquatic systems. To apply eDNA metabarcording to terrestrial arthropods, we developed a non-destructive eDNA collection method. In this method, termed "plant flow collection," we spray distilled or tap water, or use rainfall, which eventually flows over the surface of the plant, and is collected in a container that is set at the plant base. DNA is extracted from the filtered water samples and a DNA barcode region, such as cytochrome c oxidase subunit I (COI) gene, of the extracted DNA is amplified and sequenced using a high-throughput sequencer. We identified more than 38 taxonomic groups of arthropods at the family level, of which 7 were visually observed or artificially introduced species, whereas the other 31 groups of arthropods, including 18 species, were not observed in the visual survey. Put together, these results show that the developed method is effective for detecting the presence of arthropods in plants.