E-PoSa: A novel and effective tool for sampling pollen directly from flowers

Pollinator insects are declining worldwide, also due to the alteration of their diet with severe implications on their health status. Pollinators diet relies mainly on flower rewards (i.e. pollen and nectar), and a precise characterization of their chemical composition is crucial in defining pollinators' nutritional ecology. In this context, the pollen represents a challenging source to investigate, especially due to operative challenges during collection operations and to the small amounts produced per flower.Here, we designed and tested a novel, easy-to-assemble tool for pollen sampling: E-PoSa (Electronic Pollen Sampler), based on the use of a portable vacuum cleaner. We compared it with some of the most used sampling methods for pollen (i.e. anthers sieving and sampling of the whole anthers) by looking at the differences in their quantitative recovery and nutritional profile. Its applicability in ecological studies was also corroborated by an assessment of its recovery rate obtained from a panel of wildflower species in an operational environment.The data obtained showed a significantly higher pollen recovery capacity of E-PoSa compared with the conventional sieving approach and the success in retrieving enough pollen to conduct phytochemical analyses from a broad range of flower morphologies in the field. Our results also demonstrated that high purity pollen can be collected with E-PoSa and that the device does not introduce any significant variation in the nutritional analysis compared with the conventional sieving.This new sampling approach represents a cheap and easy-to-assemble tool encouraging its future use not only in the field of pollen nutrition but also in a wide variety of other contexts related to pollination ecology. Acknowledging the potential influences of the sampling techniques and moving towards shared standardized field protocols will advance the comprehension of species interactions and foraging patterns of pollinators and their nutritional needs.