Multiple Key Hosts and Network Structure Shape Viral Prevalence Across Multispecies Communities of Bees

Emerging infectious diseases (EIDs) threaten biodiversity, yet identifying key host species in complex ecological communities remains a major challenge. Here, we develop a quantitative framework combining field data, epidemiological modelling, simulations, and Bayesian inference to pinpoint key viral hosts in multispecies bee communities. Using flower-visitor interaction data and molecular virus screening, we estimate species-specific basic reproduction numbers (R0) and assess the role of both key hosts and community metrics in virus transmission and persistence. We show that, while honeybees often act as primary reservoirs for deformed wing virus and black queen cell virus, others, such as the bumblebee Bombus lapidarius, can drive the spread of acute bee paralysis virus. Viral dynamics are primarily explained by exposure to key hosts, while community effects are not as pronounced. Identification of non-honeybee key hosts challenges existing assumptions and highlights drivers of transmission and pathogen persistence in complex host-pathogen networks.