Fear of predators shortens the penis with fish

According to the Austrian biologist Alexander Kotrschal, these are probably less disturbing when flighting, according to the Austrian biologist Alexander Kotrschal about the study in “science preliminary output”.

With colleagues, Kotrschal placed 180 guppies (Poecilia Reticulata) separated into large Polish according to gender. These were modeled on the original habitat, river waters on the Caribbean island of Trinidad. As in real life, there was a predator in every Guppyte pond. This role played so reported Pike Cichlids (Crenicichla Alta).

After about a month and a half, the predatory fish had decimated the guppies to every fifth. The researchers then released the surviving women and men in predatory free basins. These descendants testified there.

Evolutionary effect investigated
In the third generation Guppy, which had grown under such circumstances, it was documented when the females how many younger spring behavior and the physique of descendants measures. Guppys served as a comparison that lived in the same basin behind a transparent wall. So they could see the predator fish, but not to be eaten by him.

The researchers’ findings:

• Guppy woman from the predatory fishing tank hurried with the wars. In general, they no longer put offspring in the waters, but they had more of it and their children were larger.

• After three generations, Guppyma dumplings had shorter cocks and genital organs after three generations. That can make you more agile and simplify its escape.

• The predatory female woman was also generally smaller and had less body weight. They were also faster.

• The man Däbnchen did not do it without strong colors. It brings you an advantage in the opposite sex: “Females usually choose colorful men.”