Effects of the gut parasite Nosema ceranae on honey bee physiology and behavior.

The common and widespread parasite Nosema ceranae is considered a major threat to the Western honey bee at both the individual and colony levels. Several studies demonstrated that infection by this parasite may affect physiology, behavior, and survival of honey bees. N. ceranae infection impairs midgut integrity and alters the energy demand in honey bees. The infection can also significantly suppress the bee immune response and modify pheromone production in worker and queen honey bees leading to precocious foraging. However, the presence of N. ceranae is not systematically associated with colony weakening and honey bee mortality. This variability depends upon parasite or host genetics, nutrition, climate or interactions with other stressors such as environmental contaminants or other parasites.