Due to the female preference, males have evolved to compete with each other for mating rights.

Among some spiders, the threat of sexual cannibalism is so serious that males have evolved elaborate courtship behaviors.

Because the biggest male usually rules the harem, males in both species have evolved to be huge relative to their female mates.

Thus, in manakins, the males have evolved adaptations to suit the females' attraction towards sound.

In other species males have evolved special weapons with which they fight over females.

The rich male has since evolved into businessmen from influential families.

As a result, only males of this species will evolve specialized mechanisms to aid in detection of the female signal.

This leads males to evolve aggressive mating behaviors which can help them acquire mates.

While some males have evolved different types of modifications to aid in grasping, others just grab females and attempt to force copulation.

In response, however, males have counter evolved, also changing the shape of their abdomens to those that would facilitate forceful mating.