Monitoring the birds and the bees: Environmental DNA metabarcoding of flowers detects plant–animal interactions

Animal pollinators are vital for the reproduction of ~90% of flowering plants. However, many of these pollinating species are experiencing declines globally, making effective pollinator monitoring methods more important than ever before. Pollinators can leave DNA on the flowers they visit, and metabarcoding of these environmental DNA (eDNA) traces provides an opportunity to detect the presence of flower visitors. Our study, collecting flowers from seven plant species with diverse floral morphologies, for eDNA metabarcoding analysis, illustrated the value of this novel survey tool. eDNA metabarcoding using three assays, including one developed in this study to target common bush birds, recorded more animal species visiting flowers than visual surveys conducted concurrently, including birds, bees, and other species. We also recorded the presence of a flower visit from a western pygmy possum; to our knowledge, this is the first eDNA metabarcoding study to simultaneously identify the intera..., Study site
Our site was within the Helena and Aurora Range (Kalamaia name: 'Bungalbin'), in the Goldfields-Esperance region of Western Australia (Fig. 1). We undertook two visits: one in spring time September 2020, when visual pollinator surveys for insect, bird and mammal pollinators were conducted for six focal flowering species – Acacia adinophylla, Eremophila clarkei, Eremophila oppositifolia, Grevillea georgeana, Leucopogon spectabilis and Tetratheca aphylla subsp. aphylla, followed by the collection of flowers for eDNA analysis, and one in autumn May 2021, when the same procedures were repeated for Banksia arborea, which was not flowering on the first visit. These plants represented a range of species with different flower morphologies and different assumed pollinators. Furthermore, many of the plant species sampled are of conservation concern, with little information on pollinating taxa currently available (Fig. 2; supplementary material 5).
Flower sample collection
A total of 17..., ,