As dominant predators of arthropod communities in natural and agricultural ecosystems, spiders

15 Noninvasive genetic approaches enable biomonitoring without the need to directly observe or 16 disturb target organisms. Environmental DNA (eDNA) methods have recently extended this 17 approach by assaying genetic material within bulk environmental samples without a priori 18 knowledge about the presence of target biological material. This paper describes a novel and 19 promising source of noninvasive spider DNA and insect eDNA from spider webs. Using black 20 widow spiders (Latrodectus spp.) fed with house crickets (Acheta domesticus), we successfully 21 extracted and amplified mitochondrial DNA sequences of both spider and prey from spider web. 22 Detectability of spider DNA did not differ between assays with amplicon sizes from 135 to 497 23 . CC-BY-NC-ND 4.0 International license peer-reviewed) is the author/funder. It is made available under a The copyright holder for this preprint (which was not . http://dx.doi.org/10.1101/011775 doi: bioRxiv preprint first posted online Nov. 25, 2014;