Effects of Increasing Levels of Anthropization and Land Use on Nosema spp. Spore Loads

The honeybee is one of the most important pollinating insects, but its survival is threatened by biotic (lack of floral resources or emerging pests) and abiotic (urbanisation) factors. In addition, high population density in hives could negatively impact bee health. Aims: Investigate the presence of Nosema spp. as a function of apiary size, beekeeping practices, proximity between apiaries, and land use. Materials: Bee samples were collected from several apiaries in Cluj County and subjected to microscopic analysis to assess the level of infestation according to the O.I.E. manual. Land use was assessed using the Corinne Land Cover package, thus analysing the different types of environments the bees have access to, based on their flight range. Results: Based on microscopic analysis of Nosema spores, differences in the level of infestation were observed between apiaries. This high variability may be related to beekeeping practices as well as environmental stressors, and differences in infestation levels between apiaries suggest the need for preventive measures to control the spread of nosemosis. Another notable element is the level of infestation in hives with overlapping flight areas, which can be explained by many factors, including natural, human and colony factors.