With the aim of fertilizing, sperm uses violence and chemical warfare.

2010/10/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Biologia

In insects, the sperm of the different males fight each other to fertilize as many eggs as possible

Two studies published in the journal Science show that in some insects the sperm must fight strongly against the sperm of other males to reach the egg.

One of the investigations has taken place at the Sirakusa University in the United States. The male fruit flies have been genetically modified so that the sperm of each one is of a different fluorescent color. Thanks to this they have seen how they compete for the best position within the female.

Thus, they have shown that the female keeps the sperm of the first male in three organ deposits, but releases part of the sperm before crossing it with another male. When the sperm of the second male reaches the place where the first is found, he competes against him and tries to mate it through the movement. This would explain why males put three times more sperm than females.

In the other research, biologists at the University of Copenhagen have shown that sperm from an ant and a male bee is harmful to sperm from another male. According to them, sperm proteins attack the sperm in competition, as the immune system cells act against strangers.