A holistic approach for the investigation of bee health

Despite current evidence is in strong disagreement with an emergency for the conservation of Apis mellifera, great concern is related to profitability of beekeeping operations. A growing involvement of veterinary science in addressing bee health topics will therefore be fundamental to preserve and protect the entire sector. The experiments in this thesis focused on two different and interdependent levels related to bee health: the biochemical level and the parasitological level. At the biochemical level the impact of plant protection products on bee physiology and survival was studied, elucidating synergistic interactions between poor nutrition and pesticide exposure in A. mellifera and between an insecticide and a fungicide in Osmia bicornis. Moreover, an innovative fingerprinting approach on honey bee haemolymph was applied to detect population imbalances in the hive. The control of Varroa infestations was studied both at the biochemical and parasitological level. A panel of biomarkers in honey bee haemolymph was applied to compare different mite control protocols. This resulted in relevant indications for beekeeping operations pursuing the least impact on nutritional status of the colonies. To guide the decision making of beekeepers, a new formic acid evaporator was tested in comparison with a more established one. Considering its widespread distribution in the country, efforts were directed also towards N. ceranae. In particular, the pivotal aspect of diagnosis was studied, proposing a new qPCR method to overcome some limits of the existing ones. In conclusion, this works fills some of the knowledge gaps of the beekeeping sector. However, many of them still need to be addressed and the upcoming menaces of climate change and dispersal of pathogens via globalization should be targeted by research efforts in the near future. Therefore, a multifaceted vision of bee health is of capital importance, aware of the complementarity of reductionist and holistic approaches.