Nosema ceranae changes semen characteristics and damages sperm DNA in honeybee drones

Abstract

In this study, we aimed to determine how infection with Nosema ceranae spores affected semen volume, sperm concentration, and fragmentation of sperm DNA in honeybees. A total of 120 one-dayold drones were marked with queen bee marking numbers, and equally divided into two groups. Drones in the infected group were individually fed with honey syrup containing 200 000 N. ceranae spores per 1 µL, while those in the uninfected (control) group were fed honey syrup without spores. The groups were then placed in two separate colonies. Fourteen days later, ejaculate was collected from the drones and was analyzed for semen volume, sperm concentration per 1 µL semen, and sperm DNA fragmentation. Compared to uninfected controls, the N. ceranae spore-infected drones showed significantly decreased semen volume and sperm concentration, as well as a higher percentage of sperm DNA fragmentation.

Keywords

• Nosema ceranae
• Apis mellifera
• sperm
• drone
• DNA fragmentation
• chromatin dispersion