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Goblin-faced spiders have excellent hearing – no ears required



Anyone who names the goblin-faced spider is clearly impressed with its giant eyes, monster-like spheres that can detect prey in the dark.

As it turns out, this nocturnal spider is notable for a completely different meaning: Hearing. A new study says a spider can hear a surprising variety of sounds from a distance of more than 6 meters, thanks to its sensory organs – on its legs.

Native to the southeastern United States, the face spider loves its prey by dangling from a vegetation cover and then flipped backwards to capture its prey in the air in a sticky net.

Curious about how the spiders can achieve such agility, Jay Stafstrom, a postdoctoral researcher in neurobiology at Cornell University, previously performed an experiment in which he covered spider eye with a piece of silicone. Interestingly, blindfolded predators are still able to catch flying insects, suggesting they are indeed hearing their exploits.

In the common sense, spiders have no ears. But there is growing evidence that some species of spiders ̵

1; such as jumping spiders, fishing spiders, and now love-faced spiders – can hear through nerve-based receptors on their legs. The receptors function like the ears, capturing sound waves and transmitting impulses to the brain. Spiders’ ability to sense the vibrations of tiptoeing prey on spider webs is well known, but it is not considered hearing. (Read how jumping spiders can see the moon.)

The impressive thing about the goblin face spider is how good they can listen, says Stafstrom, whose study is published today in the journal Current biology. Unlike some species (such as jumping spiders) that cannot hear high-frequency sounds, goblins can detect both the low-frequency sounds of insect flapping and the high-frequency chirping of birds. , their primary predator, Stafstrom discovered.

Sen Sivalinghem, a sensory biologist at the University of Toronto who was not involved in the study, said exploring advanced hearing ability in such a simple organism could help scientists learn more about how sense development consciousness.

“Understanding how sensory information is processed in the brains of relatively less complex animals with fewer neurons – and how this affects behavior and decision-making,” he said. of the organism – will provide insight into the processes and mechanisms of all brains ”. “Including ours.”

Sense

According to the study, the goblin spiders create a sticky web of silk, then stalk the flying insects in a “ballistic, head-on” twist.

In their new laboratory experiment, Stafström and colleagues inserted microscopic electrodes into the spider’s brain and also into the spider’s legs, which can respond to sounds up to an hour after being affected. cut out. Scientists suspect that the ankle organs, located near the end of each spider’s leg and responsible for sensing the vibrations, are also what they use to hear. (Find out how some spiders have brains in their legs.)

The scientists then played sounds of various pitches from a distance of about 6 feet. Electrode measurements showed that the spider’s brain and cervical organs became active when exposed to low and high frequency sounds. When scientists disabled the spider’s tarsal organ, the spider did not respond strongly to the sound, indicating that these organs act like eardrums.

To confirm the lab findings, the team also tested spiders in their natural habitat in Gainesville, Florida, playing the same sounds at a distance of 6 feet at night.

The results are the same: Spiders spread their nets when they hear low frequencies, they mimic insect wings, and stay still when listening to high frequency sounds, which indicates predators are nearby. These responses reinforce their findings that spiders actually hear, not just respond to, vibrations in the web, the study authors said.

“One of the really interesting aspects of this research is the combination of behavioral experiments with neurophysiology work,” says Sivalinghem. (See 10 stunning photos that will make you fall in love with spiders.)

He added: “It is well known that it is difficult to record brain activity in spiders, which means” we know very little about how to process sensory information and what information is important to spiders. But studies like this are filling the void.

Technology improvements

“This discovery could lead to even better sound detection technology, such as ultra-sensitive microphones,” Stafstrom said.

Because goblins have “evolved to be really good at this really bizarre behavior,” he said, “we can mimic that in some form.”

For example, he envisions a spider-like microphone or smart speaker with eight “pins,” each with a sensor, so “you can have a really good calculation of where the sound is coming from. bar, the rate at which it is emitted and where it is coming from. ”Such a device can be useful for detecting a particular voice through a variety of other verbal conversations, he said.

“We think there is an information goldmine hidden in these spiders.”


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