Nosema ceranae and RNA viruses in European and Africanized honeybee colonies (Apis mellifera) in Uruguay

Nosema ceranae is one of the causative agents of Nosemosis, a severe disease that affects the honeybee Apis mellifera. The aim of the present work was to compare N. ceranae and RNA virus infections in Africanized bees (hybrid of Apis mellifera scutellata and A. m. mellifera) and European (Italian) bees (A. m. ligustica) under field conditions. Africanized and Italian healthy colonies were relocated to an Eucalyptus grandis plantation, a place where colonies inevitably acquire Nosemosis. Fifteen and 30 days after that, all colonies presented N. ceranae spores although Africanized bees were less infected than Italian bees. Sacbrood virus (SBV) and Black queen cell virus (BQCV) were detected in both races of bees, although Africanized bees presented a lower level of BQCV infection than Italian bees. At the end of the flowering period, Africanized colonies had a larger honeybee population and produced more honey than Italian colonies. These results suggest that Africanized bees may be able to limit N. ceranae and BQCV infections within the colony, and that this may allow them to be more productive.