Clay Models and eDNA are Useful Tools for Identifying Predators of Salamanders

Abstract

Clay models are a popular technique for studying predation in nature due to their ease of deployment and minimal disruption of natural processes, but a drawback is the ambiguity of identifying predators based on bite marks. However, it is possible to amplify and sequence environmental DNA (eDNA) from these bite marks and to identify the predators responsible for attacking models. In this study, we sought to test the effectiveness of using eDNA from clay models as a means of identifying predators. We deployed in the field molded clay models that resemble Plethodon ventralis (Southern Zigzag Salamander). We then extracted eDNA from visible bite marks, amplified and sequenced the 12S rRNA mitochondrial locus on an Illumina MiSeq, and used BLAST to determine the identity of representative sequences. We identified likely predators as Procyon lotor (American Raccoon), Didelphis virginiana (Virginia Opossum), Turdus migratorius (American Robin), and Tamias striatus (Eastern Chipmunk). We believe that this technique is helpful for adding a layer of specificity to predation studies using clay models, albeit with a few potential pitfalls that we discuss.