Health Status of Honeybee Colonies Differing in Genetic Intra-Colonial Diversity

Two different levels of diversity within a colony were compared for the prevalence of pathogens and diseases. Lower genetic diversity was obtained in the colonies in which the queens were inseminated with semen collected from drones originating from a single colony, while greater was obtained in the colonies with queens inseminated with semen from drones of thirty different colonies. Bees were tested for Varroa destructor infestation, microsporidia Vairimorpha spp. infection, acute bee paralysis virus (ABPV) and deformed wing virus (DWV). Colonies with a greater genetic diversity of workers in colonies were more infested with Varroa mites than genetically uniform colonies. Varroa infestation was not found to be associated directly with the weakening of bee colonies after winter. The two experimental groups had a similar number of colonies infected with Vairimorpha, and viruses. Intensity of Varroa infestation and Vairimorpha infection did not significantly affect the overwintering of bee colonies. Colonies in which DWV was detected significantly weakened during overwintering.