Detection of Nosema spp. in worker bees, pollen and bee bread during the honey flow season

Anotace: Nosema apis and Nosema ceranae are responsible for nosemosis in the honey bee (Apis mellifera). The aim of the study was to identify Nosema spp. during the honey flow season in bee colonies, for co-infection or no infection with Nosema apis/Nosema ceranae. Hive bees, forager bees, pollen grains brought by them, and bee bread were analysed. In the infected group, 12 of 30 samples of hive bees were infected with Nosema ceranae, 7 were co-infected, 3 were infected with Nosema apis. In samples of forager bees, 21 of 30 were co-infected, 8 were infected with Nosema ceranae. The analysis of pollen demonstrated that only 2 of 30 samples were infected with Nosema ceranae, 3 of 30 samples of bee bread were infected with Nosema ceranae, 3 were co-infected and 1 of 30 were infected with Nosema apis. In the uninfected group, 13 of 30 samples of hive bees were co-infected, 2 were infected with Nosema ceranae. In the forager bees group, 12 of 30 samples were co-infected, 2 were infected with Nosema ceranae. Only 1 pollen sample was infected with Nosema ceranae and 1 was co-infected, 2 of 30 samples of bee bread were co-infected, 2 were infected with Nosema ceranae. The study demonstrated that during the honey flow season, infection by microsporidian species occurs mainly in forager bees. Pollen and bee bread may be a source of spores mainly at the beginning of the honey flow season.