Automated identification of honey bee pollen loads for field-applied palynological studies

In a changing world, it is crucial to characterise communities and their evolution over time. Because social insect pollinators forage on flowering plants around the colony, the nest potentially contains important information about the pollinated plants such as species identity and plant phenology. In this paper, we introduce new approaches to assess plant composition in a Mediterranean summer plant community from pollen foraged by honeybees. We leveraged the autofluorescence properties of the pollen load to classify plant species, both using a UV/Vis spectrophotometer in the laboratory and a dedicated prototype 'pollen analyser' adapted to field studies. Our results demonstrate that data collected from fluorescent spectra and pollen analyser measurements of pollen load from 14 plant species are specific enough to distinguish plant species. When combined with machine learning techniques, particularly the Support Vector Machine classifier, these approaches provide powerful methods to automatically identify species from fluorescence measurements of pollen load. Overall, our study shows that analysing the autofluorescence of honeybee pollen load enables the precise identification of their floral origins, paving the way for a real-time, spatially distributed observatory of flowering plants to monitor species identity, flowering phenology and long-term ecological dynamics.