Case study of non-lethal sampling for plant-pollinator networks via barcoding and metabarcoding on bumble bees in Germany

1) Insect decline is threatening ecosystem stability, making information about foraging preferences of pollinators a vital information to acquire. A powerful emerging tool to study pollinator foraging behavior is pollen-metabarcoding. This usually involves lethal sampling of insects. 2) Here, we propose a new, non-lethal way of sampling DNA for the analysis of pollen loads of bumble bees as well as the pollinator. The new methodology does not significantly harm the insect and is easy to implement in a wide range of study designs. The tool is cheap and easy to acquire, can easily be used in the field, and has the potential to become a powerful tool in studying plant-pollinator interactions. 3) To test its feasibility, plant-pollinator networks were analyzed using metabarcoding of the ITS2 region. Plants flowering at the time of collection were also recorded as a reference comparison. 4) Bumble bees with ambiguous morphology were additionally identified based on COI barcoding. 5) With the workflow developed here it is possible to gain knowledge about plants and their pollinators in a non-lethal way without reducing population sizes. This makes this method particularly suitable for endangered and protected species.