Pollination by insects is of great importance for the global food production. There is a specific need for pollination by bees in greenhouses and tunnel cultivations to increase the quantity, quality and market value of the crops. Imported bee colonies from central Europe are used for pollination of Swedish crops and have a great economic importance but are also a threat to wild Swedish bees by posing a risk of pathogen transmission between the bee species. The aim of this study was to investigate how imported bees affect the prevalence of pathogens amongst wild bees.  Analysis was performed on 236 wild bees collected in near proximity to tunnel cultivation, greenhouse cultivation and collected from two control landscapes. The abdomen of the bees was used to extract RNA/DNA for further detection and quantification of ten pathogens using qPCR. The proportion of infected bees within each group was calculated based on the results from the qPCR analysis. A two-proportion z-test was used to determine whether the difference in pathogen prevalence between the four groups was of statistically significant at α = 0.05. The results show that there was no significant difference when comparing the presence of all pathogens between bees in the test groups and the bees in the control groups (p= 0,29- 0,33). However, the prevalence of three viruses was significantly higher among bees collected in the near proximity of a greenhouse compared with bees collected from the near proximity of a tunnel cultivation (p< 0,003). For Slow bee paralysis virus the prevalence was 2,5 times higher and for Deformed wing virus and Black queen cell virus the prevalence was 3,5 and 1,3 times higher among bees collected near a greenhouses compared to near a tunnel cultivation.

Due to recent declines regarding pollinators, The Swedish Civil Contingencies Agency launched a project investigating possible biological threats towards wild bumblebees. This led to an extensive collection of bumblebees from areas in southern Sweden during the summer of 2018. The purpose of this project was to investigate the prevalence of ten bumblebee pathogens and see if there were any difference in prevalence in areas with and areas without commercial bumblebees. This study also aimed to investigate if the prevalence of the pathogens tended to fluctuate during the season. Of the collected bumblebees (Bombus spp) the ones from the late summer season were analyzed in this project, and data from the already analyzed samples from the early summer season was used. To screen the bumblebees for the pathogens a laboratory process was followed with dissections – homogenization – DNA and RNA extractions – conversion of RNA to cDNA and lastly real-time quantitative PCR. The results showed significant differences between areas with and without commercial bumblebees for some pathogens, but the results were only consistent between early and late season for Apicystis bombi and Black queen cell virus. Apicystis bombi had a higher prevalence (2,0 and 3,0 for late and early season) in areas with commercial bumblebees. Black queen cell virus had a higher prevalence (1,3 and 1,6 for late and early season) in areas without commercial bumblebees. For the seasonal fluctuation a significant difference between early and late season could be seen for the pathogens – Crithidia bombi, Apicystis bombi, Locustacarus buchneri and Sphaerularia bombi.