Here’s a comforting thought. When you arrive home and open the front door or enter your bedroom, the spiders can hear you.
It has long been known that spiders can hear sounds via leg hairs that bend in response to vibrations arriving through the air or through solid objects such as floors or walls. But until now, we thought they could only hear airborne vibrations a few centimetres or “spider lengths” away at most.
It now seems that this same approach actually lets them hear sounds up to 5 metres away.
Gil Menda at Cornell University in Ithaca, New York, and his colleagues were studying a type of jumping spider,Phidippus audax, that they assumed relied almost completely on sight and vibrations they can feel through other objects, such as leaves or floorboards.
But microelectrodes implanted in the spiders’ brains showed that neurons responded to sounds such as chairs scraping and people clapping even when the noises were made 3 to 5 metres away.
“We were very surprised,” says Menda. “Our studies extended the range of auditory sensitivity to more than 3 metres – over 350 body lengths – for our spiders.”
The team established that the spiders freeze when exposed to low-frequency sounds of about 80 to 400 hertz that resemble a low hum, or buzz. They discovered that this overlaps with the wingbeat frequency of predatory insects such as parasitoid wasps and flies, concluding that the hearing abilities they found in jumping spiders have evolved to help them avoid predators.
This makes it even LESS plausible that they would crawl in your mouth while you are sleeping, or bite you for any reason. You are a mountain that creates wind and thunder, they only want to avoid you.
WELL, to quote my former coworker who is an entomologist:
It’s not technically “hearing” as they have no ears or tympanic membranes but all the hairs sense changes in vibrational patterns. The fact that they can sense this and from such a distance is pretty amazing.
inktober day15: single young mother travels to far off lands, defends family from unscrupulous adventurers.
inspired by a cute wolf spider mom i rescued from my parent’s bathroom a few weeks ago. her babies weren’t as blob as these are but i got very tired in the home stretch of sketching this.
also i think i’m actually getting better with inks which is neato.
