The spiders facing the ogres hang down from their webs, like gymnasts, they flip back to catch insects in the air. A new study found that in order to hear the arrival of prey, spiders use their special organs to “sniff” the flaps of tiny wings.
The organs look like parallel slits cut in the spider’s exoskeleton.Located near the tip of each leg, the size of each slit is between 0.0000003 and 0.000007 inches (10-200 nm) long. These tiny gaps contain nerve cells, which can detect small pressure changes caused by sound waves rippling in the air. The organ then sends this information to the brain.
So equipped to face the ogres spider (SpinosaurusAccording to a new study published in the journal on October 29, you can hear sounds 6.5 feet (2 meters) away and pick up frequencies between 1
Jay Stafstrom, a postdoctoral researcher in sensory biology at Cornell University, said: “This is very strange to us because we don’t have such a sensory system.”
Of course humans will use their Eardrum To detect the sound, but the spider does not have an eardrum. Having said that, Stavstrom and his colleagues suspect that the spider facing the ogre may rely on some form of hearing to block prey in the air, and this new study also supports this doubt.
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The author found that certain sounds made the spider jump. As if prompted, the spider would hear the sound and suddenly perform a half-backflip, as if it was shooting at an incoming bug. According to reports, ogre spiders can be found in forest areas in Australia, Africa and parts of the United States (including Florida). Universe magazine; Little spider, Measure less than an inch (1.5-2.5 cm) long, hiding between palm leaves and other plants, and using its flexible acrobatics to catch moths, Mosquito And flying flies.
Stafstrom told Live Science that in terms of enabling spiders to capture prey in flight, this flip is “fast ballistic, very fast… and they are surprisingly accurate.” “From such a small spider, there are also very small spiders brain, Very impressive. “
Usually, spiders facing ogres are known for their impressive sight rather than hearing. “They have the biggest eye Stafstrom said. These spiders hide among predators throughout the day, pretending to be one with the plants they live on. At night, spiders appeared, and they found crawling insects on the insects with two huge night vision eyes. To catch the creepy reptiles, the spider hangs from a web near the ground, wraps the bugs in a small, stretchable web, and fixes them between the four feet.
Spiders use the same nets to catch flying insects, but they twist their bodies backwards so that the nets aim upward instead of diving towards the ground. However, it was initially unclear whether spiders rely on night vision to target their webs at flying prey.
In a previous study published in Biology Letters in 2016, Stavstrom set out to determine whether spiders facing ogres even needed to catch flying insects with their eyes. He blindfolded the spiders with dental silicone (an opaque plastic) and found that they could no longer catch crawling prey from the ground, but they could still pull insects out of the air. Stafstrom said, obviously, in addition to sight, they also rely on some other sense.
In this new study, Stafstrom and his co-authors played different sounds for the spiders to see if any sounds would trigger their iconic backflip. When exposed to low-frequency sounds between 150 Hz and 750 Hz, the spider tilted back and stretched its web as if it had caught a bug. The author points out that these low-frequency sounds mimic the flapping patterns of various flying insects. The authors found that the absence of any frequency of sound caused the spider to aim forward towards the ground, confirming that the spider uses sight rather than hearing to catch crawling prey.
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Compared with low-frequency sounds, high-frequency tones will not make spiders somersault. However, electrical recordings of spider brain cells show that certain brain cells or neuron groups respond to high frequencies, especially between 1,000 Hz and 10,000 Hz. The sensory organs in the spider’s legs respond to the same range of sounds. The author speculates that because insects in flight do not flap their wings at such a high speed, spiders may also hear the high pitch of prey birds.
Stavstrom said: “This may be an early warning sign. Birds that may kill your life may be nearby.” “We really want to know,’Can these spiders hear it?” bat“” He added, but this study did not include frequencies sufficient to mimic most bat chi.
Stafstrom pointed out that although research on spider hearing is still new, several other spider spiders can also hear sounds.
For example, a jumping spider will sense and respond to sounds 9.8 feet (3 m) away, Previously reported on Live Science. Jumping spiders have pressure-sensitive leg hairs that can respond to the movement of surrounding air particles. The spider facing the ogre also has these special leg hairs, and the legs of the jumping spider also have the same sensory organs as the ogre facing.
Stavstrom said: “We suspect that these two spiders are using these two systems.” But this has not been confirmed.
With the discovery that the spider facing the ogre uses their hearing to catch prey, Stavstrom and his team now want to know how the spider can tell which direction a given sound comes from. They plan to place the spider on the stage and play sounds from all angles to see if the spider has changed its acrobatic habits to aim the web in the corresponding direction.
Originally published in “Life Science”.