DNA metabarcoding, an efficient way to detect non-native cerambycid beetles in trapping collections?

Abstract

Individual sorting and identification of thousands of insects collected in mass trapping biosurveillance programs is a labor intensive and time-consuming process. Metabarcoding, which allows for the simultaneous identification of multiple individuals in a single mixed sample, has the potential to expedite this process. However, detecting all the species present in a bulk sample can be challenging, especially when under-represented non-native specimens were intercepted. In this study, we quantified the effectiveness of metabarcoding at detecting exotic species within six different mock communities including or not native and non-native species of European xylophagous cerambycid beetles. Although we did not observe significant differences in the total number of species detected between MinION, Illumina, and IonTorrent sequencing technologies, a greater number of individuals was detected and identified to species using MinION, including the detection of three non-native cerambycids. The three sequencing technologies also showed similar results in detecting and identifying closely related species and species at low abundance. The capture method appears to greatly influence sample preservation and detection. Indeed, individuals captured in traps containing monopropylene and water had both lower DNA concentration leading to lower species detection rates compared to individuals killed using just an insecticide without any collection medium.