Babin A., Schurr F., Delannoy S., Fach P., Huyen Ton Nu Nguyet M., Bougeard S., de Miranda J., Rundlöf M., Wintermantel D., Albrecht M., Attridge E., Knauer A.
Distribution of infectious and parasitic agents among three sentinel bee species across European agricultural landscapes.
Infectious and parasitic agents (IPAs) and their associated diseases are major environmental stressors
that jeopardize bee health, both alone and in interaction with other stressors. Their impact on
pollinator communities can be assessed by studying multiple sentinel bee species. Here, we analysed
the field exposure of three sentinel managed bee species (Apis mellifera, Bombus terrestris and
Osmia bicornis) to 11 IPAs (six RNA viruses, two bacteria, three microsporidia). The sentinel bees
were deployed at 128 sites in eight European countries adjacent to either oilseed rape fields or apple
orchards during crop bloom. Adult bees of each species were sampled before their placement and
after crop bloom. The IPAs were detected and quantified using a harmonised, high-throughput and
semi-automatized qPCR workflow. We describe differences among bee species in IPA profiles (richness,
diversity, detection frequencies, loads and their change upon field exposure, and exposure risk), with
no clear patterns related to the country or focal crop. Our results suggest that the most frequent IPAs
in adult bees are more appropriate for assessing the bees’ IPA exposure risk. We also report positive
correlations of IPA loads supporting the potential IPA transmission among sentinels, suggesting
careful consideration should be taken when introducing managed pollinators in ecologically sensitive
environments.