Postcopulatory Sexual Selection

Abstract

Sexual selection is the evolutionary process that increases frequency of genes that provide reproductive advantages to organism. Though earlier it was considered that selection takes place before copulation supporting good genes hypothesis. However, studies provide sufficient evidence that selection is not only limited to pre-copulation. Postcopulatory selection came into light when it was found that females are far away from being monogamous and mate with multiple mates. Promiscuity in females led to evolution of such selection. It is the reproductive tract of female, where competition between sperm of different males takes place. In the present chapter, we discuss about mechanism, types, and consequences of postcopulatory sexual selection. The mechanism of postcopulatory sexual selection either includes male–male competition or cryptic female choice. Sperm competition is widely occurring phenomena in different taxa of insects. Polygamous females can store sperms from different males and then selection occurs by different means, such as sperm displacement, sperm flushing, sperm stratification, etc. Cryptic female choice is the ability of female to bias fertilization success of males. Both kinds of postcopulatory sexual selection create powerful evolutionary forces and have important impact at both molecular and evolutionary levels.