Available methods for the sampling of nectar, pollen, and flowers of different plant species

Background: The new draft EFSA guidance document introduces additional assessment factors for pollinators other than honey bees. However, there are no standard test protocols available. Therefore, the only way for risk assessment refinements, are a more precise estimate of the potential exposure in nectar and pollen. The aim of the paper is to present available sampling methods of nectar and pollen but also tries to refine methodology for sampling of nectar and pollen mentioned in the guidance document.
Results: Nectar can be collected by hand from a wide variety of crop plants. This can be done with the help of capillaries as well as with centrifugation. Pollen can be collected with manual sampling or the help of a suction pump. Bees and bumble bees can be used for both matrices with many plants. Solitary bees are able to collect pollen. More detailed results are presented for oil seed rape and Phacelia.
Conclusion: Nectar and pollen can be collected from flowering crop plants visited by pollinators in amounts that are high enough to allow residue analysis. However, the minimum number of bees needed to collect the amount is not 20 but much higher, depending on the species of plant sampled. At least 200 honey bees should be collected for each matrix.