Environmental DNA metabarcoding from flowers reveals arthropod pollinators, plant pests, parasites, and potential predator–prey interactions while revealing more arthropod diversity than camera traps

Abstract

Abstract Arthropods can strongly impact ecosystems through pollination, herbivory, predation, and parasitism. As such, characterizing arthropod biodiversity is vital to understanding ecosystem health, functions, and services. Emerging environmental DNA (eDNA) methods targeting trace arthropod eDNA left behind on flowers have the potential to track arthropod biodiversity and interactions. The goal of this study was to determine the extent to which eDNA metabarcoding can identify plant‐arthropod and arthropod‐arthropod interactions and assess eDNA metabarcoding compared to conventional sampling. We deployed camera traps to document arthropod activity on specific flowers, sampled eDNA from those same flowers, then performed a metabarcoding analysis that targets a partial fragment of the cytochrome c oxidase subunit I gene (COI) to determine all arthropod eDNA present. We found that our eDNA metabarcoding analysis detected small arthropod pollinators, plant pests, and parasites, and shed light on potential predator–prey interactions while detecting 55 species compared to just 21 species from conventional camera trapping. The camera trapping survey, however, detected larger, more conspicuous nectarivores more successfully. We also explored the ecology of residual arthropod eDNA, finding that rainfall had a significant negative effect on the ability to detect residual arthropod eDNA. Preliminary evidence also indicates flower species may impact the amount of arthropod eDNA that can be detected. We found that eDNA metabarcoding can provide clues to potential predator–prey interactions on flowers and highlights the potential insights that can be gained from future eDNA metabarcoding studies. We show that eDNA metabarcoding is a valuable tool for not only detecting pollinator communities but for revealing potential interactions among plants, pollinators, pests, parasites, and predators. Future research should focus on how to improve the detection of large pollinators/nectivores and studying the ecology of residual arthropod eDNA to further explore this method's utility.