Natures wonders: spider web giant hearing aide (Introduction)

by David Turell , Thursday, March 31, 2022, 15:37 (966 days ago) @ David Turell

Certain spiders found to use it that way:

https://www.the-scientist.com/news-opinion/spider-uses-its-web-like-a-giant-engineered-...

"Bridge spiders “outsource” their hearing by building webs that double as acoustic arrays, allowing them to perceive sounds from great distances.

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"The bridge spider uses its web as an engineered “external ear” up to 10,000 times the size of its body, according to a preprint study posted to bioRxiv on October 18. The discovery, which has not yet been peer reviewed, challenges many assumptions that scientists have held for years about how spiders and potentially other arthropods navigate and interact with the world around them.

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"Spiders—both orb-weavers and others—are perfectly capable of hearing at closer distances without their webs thanks to the tiny hairs and organs on their legs that sense vibrations as air flows past. But the majority of spider biologists assumed that they could only hear sounds in their immediate vicinity, senior study author and Cornell University neurobiologist Ronald Hoy tells The Scientist.

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“'That is one of the hardest parts: showing that they don’t have a little hidden ear on them that’s picking it up,” Miles tells The Scientist. “To do that, we created a sound source in the air that would propagate sound over a very short distance.”

"Once they heard the signal, the spiders responded by crouching, flattening out, or otherwise giving a startled response, the study authors explain. Because the web is so much larger than the spider, the paper suggests this mechanism allows the spider to hear noises it would otherwise miss, such as birds or crickets from over ten meters away.

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"The researchers speculate that spiders may increase their hearing range to help dodge predators or track prey, but the spiders in this experiment primarily responded to the noise stimuli with apparent alarm and confusion." My bold)

Comment: a fascinating finding, but note the bold. Teh researchers aren't sure what it means to the spider. Other studies have shown spiders sense movement in the web of trapped insects.