That's Cool, We Need That: Spiders That Can Fly With Silk Parachutes

June 15, 2018

This is a gif of a crab spider taking to the skies thanks to a parachute it created out of some 50 - 60 ten-foot long strands of ultra-fine silk -- some strands so fine they're actually thinner than the wavelength of visible light (400 - 700 nanometers). Up, up, and awaaaaay! Thankfully, the crab spiders that utilize this flying technique are tiny (~5 millimeters long), so you don't have to worry about any palm-sized spiders landing on your face. Those will crawl up your leg to get there. Also, in my nightmares spiders fly totally different.

[Technical University of Berlin aerodynamics engineer Moonsung Cho] found that before flying away, the spiders would lay down an anchor silk strand for safety. They would then reach one of their front legs into the air to evaluate how fast the wind was blowing, and from which direction. That's the spider equivalent of licking your finger and sticking it in the air.

If the wind conditions were just right--which, for these crab spiders, meant less than 7.3 miles per hour (3.3 meters per second) with a nice upward draft--they stood up very straight, stuck their butts in the air, and produced 50 to 60 nanoscale silks that lifted them into the skies. On average, those silks were nearly 10 feet long. Once they let go of their anchor strands, they were gone.

I can't imagine the spiders having much control over where they actually land after they take to the skies, but who cares -- wherever you go, there you are. "What does that even mean?" No clue, but I'll be there if you need me. "Where is there?" Happy hour, come buy me a cold one.

Keep going for a gif of a crab spider sticking a leg out to determine if the wind is right for flight.

Thanks to Alexander P, who started talking way more aerodynamics than I felt smart enough to listen to.

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