Spotted spiders emitting a

Sound does not make up an important part of the lives of most spiders, because they do not have ears or any other distinctive sound sensing organ. So why do spiders use "sound" to invite their partners and how do they feel the sound?

Spiders emit a "cry" to invite their partners

The howling of wolves is to signal that they are around, or that it is calling their partner. But the newly discovered wolf spider , called Gladicosa gulosa , can sound like a murmur with a very small frequency sound. Scientists do not know whether the object it wants to ' flirt' actually hears the sound coming out.

Female spiders can only sense sound vibrations in their legs, but if they do, females can only sense sounds when both females and males stand on the same surface.

Spiders can emit a "cry" to invite their partners.

Most animals use sound to communicate. In fact, Cornell University has created a digital library of over 200 000 sounds of animals. But for spiders, sound does not make up an important part of their lives. Because spiders don't have ears or any other distinctive sound sensing organ.

This is probably the biggest surprise for Alexander Sweger when he discovers one of the wolf spiders communicating with sound.

Sweger is a behavioral ecologist at the University of Cincinnati in Ohio state. He is currently working on his PhD thesis. In the laboratory, he works around the wolf spiders.

Among these wolf species, there is a species of spider that, during a century known as the loving spider. Biologists suspect that this particular wolf spider can use sound to signal to a partner. But no one has actually confirmed this, Sweger said. So he decided to study.

The sound emitted creates two types of waves. The first is a short wave. It moves surrounding molecules, only detected over a very short distance. This type of wave is followed by a longer wave creating indigenous changes in air pressure, Sweger explained.

Most animals, including humans, can be identified by the second wave of sound waves. But spiders can make sounds that cannot hear sounds according to scientists at the University of Cincinnati. describe their findings in Pittsburgh, PA during the annual meeting of the American Audio Association (ASA-Acoustical Society of America).

How does this spider sound?

At the time of looking for a mate, the male wolf spiders attracted the attention of the spiders by creating "flirtatious" vibrations , Sweger said.

A spectral image of oscillations from the "murmur" created by Gladicosa gulosa male spider.

They produce sounds due to the vibrations of a part of the body, similar to how crickets make a sound, to impress females. Male spiders that do not receive the consent of females may be 'eaten by females' . Successful " courtship " males will be allowed to mate and live with their children.

Spiders that can make a noise 'are creating similar vibrations that may be more or less like the North American spider spiders' , Sweger said. 'They are using the same structure and forming vibrations'.

But scientists show that compared to the vibrating sounds produced by other wolf spiders, the sound is made by the most powerful Gladicosa gulosa .

Besides, Sweger also discovered more, the leaf surfaces can transmit sound produced by spiders better than other materials.

If a person stands a few meters away from where the spiders are inviting their partner, they can hear the sound they emit.

Flirt with sound

So why create sound waves that can be heard when the male just transmits a few vibrations that flirt with the female spiders? This is really a puzzle. And Sweger's experiment can give an answer: this sound is just accidentally created.

The vibrations created by this spider, can only be heard when they are created on the surface of paper or leaves when the extremely loud sound can transmit the message of the male spider to the female spider. long-distance. But female spiders can only 'listen' if it is standing on a surface that can transmit sound, such as leaves.