Spider webs as eDNA tool for biodiversity assessment of life's domains

The concept of environmental DNA (eDNA) utilizes nucleic acids of organisms directly from the environment. Recent breakthrough studies have successfully detected a wide spectrum of prokaryotic and eukaryotic eDNA from a variety of environments, ranging from ancient to modern, and from terrestrial to aquatic. These numerous sources promise to establish eDNA as a tool for diverse scientific settings. Here, we propose and establish spider webs as a source of eDNA with far reaching implications. First, we conducted a field study to track specific arthropod targets from different spider webs. We then employed high-throughput amplicon sequencing of taxonomic barcodes to investigate the utility of spider web eDNA for biodiversity monitoring of animals, fungi and bacteria. Our results show that genetic remains on spider webs allow the detection of even the smallest target organisms. We also demonstrate that eDNA from spider webs is useful in research of community compositions in different domains of life, with potentially highly detailed temporal and spatial information.