Why both sexes of the species don't show equal level of Competition?

Question

In most species, it is seen that either males or females have evolved to be aggressive towards approaching members of the same species of the same sex and maintaining strict territorial boundaries. The logical explanation is that such behavior is advantageous in the evolutionary context. If you increase competition, then the chance of genes suited to the environment getting passed on increases. Obviously, if one male wards of another male from his territory then the genes possessed by him are positively selected for. In such a scenario, why haven't both the sexes developed a similar level of aggressive competition (Wouldn't this also increase the chance of genes that are suited to the environment getting passed on?)

Answer 1

One explanation for why it is generally the male which shows aggression towards other males is that he needs to actively avoid copulation by other males for his genes to be past on. In most species a female could mate with multiple partners and her genes would be past down regardless of which males sperm ends up fertilizing her eggs. The male is different because he must copulate with the female and than ensure that no other males copulate in order to ensure that his sperm fertilizes her eggs and his genes get passed on. Therefore, it is beneficial for males to be aggressive towards other males while females are not aggressive to other females.