Spatio-temporal dynamics of honey bee–pathogen networks: Implications for colony health and productivity

Pollinator declines threaten biodiversity and food security, with honey bees ( Apis mellifera ) suffering widespread losses due to multiple interacting stressors. Pathogens —including Varroa destructor , associated viruses, and Vairimorpha ( Nosema ) ceranae — form complex antagonistic communities within honey bee colonies, yet the structure of these interactions remains poorly understood. Evaluating spatial and temporal variation in host-pathogen networks is essential for predicting colony performance. This study aimed to (1) characterize the individual-based network of honey bee colonies and their pathogens, and (2) assess how network structure relates to colony population dynamics and productivity. To do so we sampled ∼400 honey bee colonies in the region of Extremadura (SW Spain), encompassing both spatial and temporal variability at smaller (apiary, season) and larger (locality, year) scales. We measured variables related to population dynamics (adult bees, brood) and colony productivity (pollen, honey), as well as loads of four of the most important pathogens of honey bees, V. destructor , N. ceranae , DWV and CBPV, in order to relate interactions with pathogens with colony performance. Host–pathogen interactions showed strong spatial and temporal structuring, with colonies dominated by a single pathogen in specific locations and in specific times. This generated distinct network modules differing in infection levels, population dynamics, and productivity. Colony declines were mainly driven by overall pathogen load and V. destructor interaction frequency, although some low-performing modules were unrelated to pathogen infection, suggesting additional environmental stressors. These findings indicate that 1) targeted management of the most vulnerable network modules could be more efficient than broad sanitation strategies, and 2) network modularity may prevent pathogen spread, so avoiding connecting modules may ease management strategies.