Why so little bigger spiders male spiders?

Spiders cling to elastic silk thread, taking advantage of the wind to overcome the distance to feed. And that's why the male spider is always smaller than the female spider to take on the role of a 'bridgeman', says BMC Evolutionary Biology .

Biologist Guadalupe Corcobad, Spain's National Research Council and colleagues studied the behavior of spiders in lab wind blowers. She said: 'Among the species that is bridging is the main way that the smaller males are, the better' bridges' and the greater the chance of having sex. They always won the race to be picky by the girls. Reducing the size, that is the pressure of natural selection '.

The "bridging" behavior of spiders makes males always "smaller" than females.

Researchers tracked 204 male spiders of 13 different species of spiders. They found that the female spiders did not ask the boys to be small because they understood the 'good-looking' athletic boys and had the advantage in producing healthy children. But the boys were clumsy, moving hard, not reaching the place where they were dating. Life after life, small spiders always dominate, making a 'big husband and wife' characteristic of spiders.

Corcobado emphasized that the 'bridging hypothesis' to explain the difference in size between males and females is entirely in line with other theories. But previous research suggests that the birth of children is the main motivation to make the difference between the two varieties. However, this hypothesis alone does not explain why in this species, males are always larger than females, in the other, males are smaller.

It was not until Darwin's time that people could explain why male animals were usually bigger, but the 'bridging' hypothesis found the opposite reason for spiders, why he was often so small on the side. next to you.