Specific Mechanism of Sperm Storage in Avian Oviducts

Abstract

The capability for sperm storage in the female genital tract is frequently observed in vertebrates as well as in invertebrates. Because of the presence of a system that maintains the ejaculated sperm alive in the female reproductive tract in a variety of animals, including insects, fi sh, amphibians, reptiles, birds, and in mam- mals, this strategy appears to be advantageous for animal reproduction. Although the occurrence and physiological reasons for sperm storage have been reported extensively in many species, the mechanism for sperm storage in the female repro- ductive tract has been poorly understood until recently. In this chapter, we report our recent fi ndings on the mechanism of sperm storage in avian oviducts, especially data obtained from the Japanese quail ( Coturnix japonica ), as an experimental model. Because sperm storage in birds occurs at body temperature (i.e. 41 °C), elu- cidation of the mechanism of sperm maintenance in the avian oviduct may open up new avenues for the development of novel strategies for sperm storage in vitro with- out cryopreservation.