Data from: Unshared on the top: strong segregation of pathogen communities between western honey bees and wild bees in a retreating glacier foreland

Shared flowers can facilitate pathogen transmission between managed honey bees and wild bees, yet this process remains poorly understood in ecosystems undergoing rapid environmental change. Using a glacier foreland in Switzerland, we present the first study on how glacier retreat stages and bee life-history traits influence pathogen occurrence across honey bees and wild bees. We screened the deformed wing (DWV), acute bee paralysis (ABPV), chronic bee paralysis (CBPV) viruses, the microsporidium Nosema ceranae, and the trypanosomatid Lotmaria passim. While all screened pathogens were detected in honey bees, only N. ceranae and DWV occurred in wild bees, though DWV strains differed between hosts (A in wild bees, B in honey bees). This clear segregation of pathogen communities between honey bees and wild is likely explained by the different floral resources used between the two bee groups, overall forming a moderately specialised and not nested network with honey bees especially targeting few plant species rarely visited by wild bees. Sociality and nesting habits did not explain pathogen loads, whereas glacier retreat stage significantly influenced DWV abundance, with higher loads in older successional stages. This case study provides a fascinating example of how the use of floral resources by honey bees and wild bees, alongside the landscape changes induced by glacier retreat, can greatly influence pathogen transmission dynamics.