Data from: Seminal fluid of honeybees contains multiple mechanisms to combat infections of the sexually transmitted pathogen Nosema apis

The societies of ants, bees and wasps are genetically closed systems where
queens only mate during a brief mating episode prior to their eusocial
life and males therefore provide queens with a lifetime supply of
high-quality sperm. These ejaculates also contain a number of defence
proteins that have been detected in the seminal fluid but their function
and efficiency have never been investigated in great detail. Here, we used
the honeybee Apis mellifera and quantified whether seminal fluid is able
to combat infections of the fungal pathogen Nosema apis, a widespread
honeybee parasite that is also sexually transmitted. We provide the first
empirical evidence that seminal fluid has a remarkable antimicrobial
activity against N. apis spores and that antimicrobial seminal fluid
components kill spores in multiple ways. The protein fraction of seminal
fluid induces extracellular spore germination, which disrupts the life
cycle of N. apis, whereas the non-protein fraction of seminal fluid
induces a direct viability loss of intact spores. We conclude that males
provide their ejaculates with efficient antimicrobial molecules that are
able to kill N. apis spores and thereby reduce the risk of disease
transmission during mating. Our findings could be of broader significance
to master honeybee diseases in managed honeybee stock in the future.