The spider uses the web to listen better

Spiders don’t just use their webs to catch delicious snacks. Research has now shown that animals also use their spider webs as a sensitive microphone. They can identify sound sources such as predators, perhaps even at great distances.

Anyone who has ever seen the making of a spider web can only admire it. What a delicate construction, and how does the animal actually manage to make the web so regular, with the wires spaced evenly?

So the web is vital to the spider that builds it (not all species do this). He holds his food with it. It is known that the spider reacts instantly when something flies into the web, and it can also be seen in practice.

External microphone

But this web also acts as an external microphone which has now been shown for the first time. Scientists from Binghamton University in the United States, among others, have shown through experiments that spiders rotate, deflate or lie down in response to a sound source in the air. They described their research in an article in the language of PNASwhich was released this week.

Hunting spiders in the nature reserve

The researchers caught spiders in a nature reserve a few kilometers from their university and had them build spiderwebs into wooden frames in their lab. Then they put the spiders in a noise-free room (dead room) for the experiments.

They always placed a sound source at a certain distance from the web and photographed the spider’s reaction. He reacted, for example, by turning his body or extending his legs.

long range sound source

Importantly, they showed that the animal almost always responds to a sound source away from the web. This shows that the spider can perceive the vibrations in the web that are caused by the transmission of sound through the air. This is very different from the fly moving the web through collision.

direction detection

With slight variations in this experiment, it became apparent that spiders could also detect the exact direction of incoming sound. Measurements showed that the sound through the air is almost completely extinguished before it reaches the spider, but it spreads through the webs almost unquenched. So the animal really reacts to the indirect vibrations of its network caused by the external sound.

to vote

And what is very special, it seems that the spider can ‘tun’ its web, in other words making it sensitive to sounds of different frequencies. By shrinking or tightening his body, he changes the tension on the threads. This makes it sensitive to a different frequency. The premise is that the spider “scans” the environment in this way for various sound sources.

Other types of spiders

And so the team at Binghamton University has gotten much wiser regarding the spider’s auditory behavior, but there are still plenty of research questions. For example, researchers are curious about how spiders later use the sound they perceive through their web. In addition, only one species of spider has been studied so far. The team wants to test whether other spider species also use their webs to extend their hearing.

In this video the researchers talk about their work:

Open photo Jonathan Cohen photo

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