Pollen microbiomes of solitary bees (Osmia rufa L. syn. O. bicornis) from seed orchards

The red mason ( Osmia rufa L. syn. O . bicornis ) is a solitary bee that is commonly used for pollination of fruit crops. Given the declining numbers of pollinators in various environments, the mason bee has not only become an effective insect as an additional pollinator, but sometimes it becomes the main species that is used to increase the yield of crops. Due to easy rearing and not showing aggressiveness towards people. The individual features of the mason bee have made the interest in this species constantly growing. Currently, the wild bees is more important for the forestry and production the seeds. So far, only the honeybee ( Apis mellifera mellifera ) has been successfully used to work in forest areas, especially with the flowers of Tilia cordata Mill. The rearing of mason bee ( Osmia rufa L.) in forest areas is new. The paper presents information on the microbiome of pollen collected from the brood chambers of the solitary bee Osmia rufa L. in various forest biotopes: Tilia cordata Mill, Quercus petraea Liebl. and Prunus avium L. The presence of five groups of bacteria was found in all analyzed pollens were rich in α-Proteabacteria , Actinobacteria and Firmicutes , while β -Proteobacteria and Bacteroides were present in a lower level. Despite the presence of bacteria in the pollen, no increased bee mortality was observed in any of the bee nests of forest biotopes. It was found that the forest environment does not pose a threat to the development of Osmia rufa L. bees.