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.

Moving toward stock units identification based on spatial population structure of marine species in the Mediterranean Sea and adjacent waters through multidisciplinary and holistic approaches for the sustainability of fisheries resources

Investigating stock identity of marine species in a multidisciplinary holistic approach can reveal patterns of complex spatial population structure and signatures of potential local adaptation. The population structure of common sole (Solea solea) in the Mediterranean Sea was delineated using genomic and otolith data, including single nucleotide polymorphisms (SNPs) markers and otolith data. SNPs were correlated with environmental and spatial variables to evaluate the impact of these features on the actual genetic population structure. Integrated holistic approach was applied to combine the tracers with different spatio-temporal scales. SNPs data was also used to illustrate the population structure of European hake (Merluccius merluccius) within the Alboran Sea, extending into the neighboring Mediterranean Sea and Atlantic Ocean. The aim was to identify patterns of neutral and potential adaptive genetic variation by applying seascape genomic framework. Results from both genetic and otolith data suggested significant divergence among putative populations of common sole, confirming a clear separation between Western, Adriatic Sea and Eastern Mediterranean Sea. Evidence of fine-scale population structure in the Western Mediterranean Sea was observed at outlier loci level and in the Adriatic. Our study not only indicates that separation among Mediterranean sole population is led primarily by neutral processes, but it also suggests the presence of local adaptation influenced by environmental and spatial factors. The holistic approach by considering the spatio-temporal scales of variation confirmed that the same pattern of separation between these geographical sites is currently occurring and has occurred for many generations. Results showed the occurrence of population structure in Merluccius merluccius by detecting westward–eastward differentiation among populations and distinct subgroups at a fine geographical scale using outlier SNPs. These results enhance the knowledge of the population structure of commercially relevant species to support the application of spatial stock assessment models, including a redefinition of fishery management units.