Reduced parasite burden in feral honeybee colonies

Parasites are the main threat for managed honeybee ( Apis mellifera ) colonies. It is unknown whether feral colonies that escaped from apiaries benefit from parasite-reducing mechanisms like swarming or suffer from high parasite pressure due to the lack of disease management. We compared the occurrence of 18 microparasites among managed (N=74) and feral (N=64) colony samples from Germany using qPCR. We distinguished five colony types representing differences in colony age and management histories, two variables potentially modulating parasite prevalence. The number of parasite taxa was lower in feral colonies (mean: 5.4) than in managed colonies (mean: 6.1). Parasite community compositions also differed, with Trypanosomatidae, Chronic bee paralysis virus, and Deformed wing viruses A and B being less prevalent and abundant in feral colonies. Parasite burden was lowest in newly founded feral colonies, intermediate in overwintered feral colonies and managed nucleus colonies, and highest in overwintered managed colonies and hived swarms. Our study confirms the hypothesis that swarming temporally reduces parasite pressure in feral honeybee colonies. Furthermore, differences in the environment between wild nests and hives at apiaries must be involved in explaining the observed differences. We conclude that feral honeybees are unlikely to contribute significantly to the spread of bee diseases. ### Competing Interest Statement The authors have declared no competing interest.