Testing newly developed PCR primers for high-specificity enrichment of bees from terrestrial eDNA

OBJECTIVE: Plant-derived environmental DNA (eDNA) considerably improved our ability to study terrestrial arthropod communities. However, bee pollinators are still underrepresented in eDNA analyses. Here we designed several PCR primers based on previously published primers, to enrich insect eDNA from plant-derived eDNA. We validate the primers with a focus on their utility to reconstruct pollinator communities, particularly bees. We tested our primers using mock communities of different bee species and field collected flower eDNA samples. RESULTS: All our primers are highly promising to enrich insect eDNA from plant material. They recovered all bee species from the mock communities and approximated their relative abundance. Moreover, we found highly diverse insect communities from field-collected samples using the new primers. Interestingly, the original, unmodified primer performed, for the small dataset we analysed, slightly better for recovering bees compared to the ones designed by us especially for bees. Combining all primers seems to be the most effective. Our study highlights the great promise of eDNA metabarcoding for the monitoring of plant associated insects, especially bees. Each of the primer sets tested show similar results in bee and arthropod community diversity making them a good choice for monitoring arthropods and especially bee pollinators.