Amwaprin is a honeybee sperm-binding protein that inhibits sperm motility and enhances sperm viability

Abstract

Mated queen honeybees store viable sperm in their spermathecae for egg fertilization throughout their lifetimes, which can span several years. However, the mechanism by which queen honeybees store sperm for extended periods has remained a longstanding question. The molecular basis for the long-term survival of stored sperm in queen honeybees is linked to minimized energy metabolism and reduced production of reactive oxygen species (ROS), but the specific factor responsible for such changes remains unknown. In this study, we present the first evidence of the presence of Amwaprin, a sperm-binding protein, in the seminal and spermathecal fluids of honeybees. We observed that Amwaprin acted as a sperm-binding protein primarily expressed in the testes and spermatheca of honeybees. A lack of binding between Amwaprin and the sperm surface resulted in altered sperm morphology, increased sperm motility, elevated H2O2 production, and decreased sperm viability. Our data demonstrate that Amwaprin inhibits sperm motility and enhances sperm viability. These findings suggest that the reduced sperm motility caused by Amwaprin binding in queen bees’ spermathecae contributes to the long-term survival of stored sperm by minimizing energy metabolism and ROS production.