Beedna: Microfluidics and Metabarcoding Reveal Pollinator Communities From A Single Flower

Biodiversity is being lost at an alarming rate, spanning habitats, ecosystems, and geopolitical boundaries with extinction rates exceeding those of the last five mass extinction events. This modern mass-extinction event has been precipitated by anthropogenic activities, and the impacts have fallen incredibly hard on pollinator species. Consequently, numerous pollinators have been added to the Federal Register as threatened or endangered, signaling the vital importance to pollinators to North American ecosystems and economies. The loss of pollinator biodiversity is of particularly noteworthy, as it reduces plant reproductive success, erodes ecosystem services provided by pollination, and drives staggering economic losses. Rapid, efficient, and accurate assessment of pollinator communities is a conservation imperative to inform adaptive management strategies stanch the loss of this critical component of biodiversity. Here we assess the efficacy of environmental DNA (eDNA) to document pollinator communities. In a controlled greenhouse experiment, we exposed flowers from three species to the Common Eastern Bumble Bee (Bombus impatiens). eDNA was sampled using a variety of methods (swabbing, whole flower preservation, and nectar sampling) and presence of pollinator DNA was assessed via microfluidic metabarcoding. Also, the same data were collected in field settings as described above. Our results reveal that microfluidic metabarcoding of flower-derived eDNA is an effective means of documenting pollinator communities. We also find that sampling and DNA extraction method choice, flower morphology, bioinformatic pipeline choice, and other factors can influence the pollinator community that is detected. Finally, we discuss how emerging eDNA chemistry and technology can be leveraged to improve measuring and monitoring of pollinator biodiversity in the Anthropocene.