[The long-term storage of spermatozoa and its role in vertebrate fertilization]

A hypothesis according to which the prolonged sperm storage in female sex tracts optimizes the fertilization process, permitting to synchronize an encounter of completely formed fertile spermatozoa and ovule under the most favourable for syngamy conditions is proposed. Spermatozoa in the state of "conservation" are the main source of male gametes under internal fertilization. Synchronization in encounter of gametes is achieved by the action on sperm-storage structures of follicular fluids, which brings about evacuation of a portion of sperm-storage structures to be in time with ovulation: yield, reactivation and advancement of sperm to the site of fertilization. The activating agents of follicular fluids act inside the oviduct. The limited number of spermatozoa is sufficient for successful fertilization. Ovule participates actively in the fertilization process.