Must perform a new performance

Because there is a shield to protect the genitalia, the red-rimmed hips can choose the guys they like to mate. In order to be given her privilege, the male must perform complex melodies.

A male red-rimmed pike slams his long legs in the middle to the water while hugging his children.Photo: Newscientist.

The girth ( Gerridae ) is a family of insects capable of moving on water. In the breeding season, males beat their middle legs to the surface of the water to create murmur melodies on the water to attract females. Then they have the right to choose a partner because the children have nothing to protect the genitalia. Therefore, a frame may be mated by many males but cannot resist.

However, individuals of the red-backed crested species that live in mountain streams in Korea, Japan, and China are more fortunate than most of the Gerridae. They have a diaphragm in the genitals, so they have the right to choose a partner. The 'ladies' only open the shield if they are impressed with the male music performance. The more complex the melody, the more likely the male's chance of getting sex is.

Piotr Jablonski, a scientist from the Polish Center for Ecological Studies, and expert Chang Han of Seoul National University (South Korea) followed the confession rituals of the red-backed girth.

They found that, in order to have children for mating, the male red horseshoe must 'perform' three consecutive tunes with their feet for at least 15 minutes. First they had to hug the female from behind and try to put her in a mating position with her front legs. Then they stretch their long legs in the middle and hit the water to create a melody. The male has just beaten his legs and put his genitals into the female shield (the shield only covers part of the genitalia).

Finally, the female will lift the shield if it is satisfied with the performance of the male. By that time the male stopped beating her legs to devote her strength to the rain.

Jablonski and Han assumed that beating their feet on the surface of the water was a necessary action for the mating process in the red-backed species. First, the health of males is assessed through tone quality. Evidence is that children just want to mate with the 'guys' with the most complex melody. The two researchers speculated that even females were able to push the male's sperm out if they found another guy more attractive.

"In the red-rimmed species, it's like taking the initiative in love games. Perhaps the Creator gave them a genital barrier to counter the risk of being attacked by rough males." Tim Birkhead, a researcher from Sheffield University (UK), commented.