Give keys to understanding the large sperm of vinegar flies

2016/05/30 Etxebeste Aduriz, Egoitz - Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Eboluzioa

A group of researchers explains how male vinegar flies have come to develop giant sperm. Vinegar fly sperm (Drosophila melanogaster) can reach 5.8 cm in length, 20 times more than body length, and a thousand times more than human sperm. And it is a rare phenomenon, since in most animals sexual selection has caused the opposite: produce small and many sperm, and not few and large.

In a recent paper published in the journal Nature, researchers have found that stronger and healthier males produce more and more sperm; and that sperm length has evolved with the length of the seminal receptacle of females. That is, throughout evolution it has tended to increase the seminal receptacles of females, thus choosing larger sperm and therefore the best males. At the same time, the male with the highest sperm has been more likely to transmit their genes.