Study of microbial composition of different types of pollen

Bee-collected pollen is an essential protein source for honey bees and bumblebees colonies. Its quality directly affects bee health. Furthermore, bee-collected pollen used by people as a vitamin and energy supplement. We estimated the quality of pollen samples using bumblebee micro-colonies and high-throughput sequencing for the presence of microorganisms. We demonstrated that samples of bee-collected pollen have different quality, as assayed from their effect on the development of bumblebee micro-colonies. Seventeen percent of the tested samples were of low-quality and could not be used in the bumblebee colony production. We selected a most “positive” and “negative” samples and analyzed it on microorganisms and pathogens. High-throughput sequencing revealed that the most common microorganisms in the bee-collected pollen were Acinetobacter spp. and bacteria of the genera Lactobacillus and Lactococcus. No pathogenic bacteria infectious for honey bees or bumblebees have been identified in the analyzed pollen samples. Among potentially deleterious microorganisms were bacteria from Enterobacteriaceae family. Nosema apis and Nosema ceranae were detected in 4 samples and Ascosphaera sp. in 6 samples. The CBPV, IAPV, DWV, SBV, and KBV viruses were identified in the pollen samples. We failed to find the dependence between the presence of these microorganisms or viruses and the impact of the samples on the bumblebee development. It is possible that factors affecting pollen quality are the absence of certain biologically active compounds or the presence of pesticides.