Male will compete for the most "charming" female, so the most "charming" female get the "strongest" male. Usually being "charming" mean better productivity and "better" genetics. So male take the strategy of spreading the sperm to as many female as they can. While female take the strategy of obtaining the sperm from the strongest male they can. The above strategy depends on the different physiology of female and male.
male spread their sperm to as many female as they can because male do not get pregnant; female try to choose the "right" male because they invest a lot for pregnancy.