YouTube / BBC
YouTube / BBC

The Hermit Crab of Spiders

YouTube / BBC
YouTube / BBC

The Olios coenobitus spider lives in Madagascar, and it's basically the hermit crab of spiders: It hangs out in empty snail shells. In this video from the BBC's Madagascar, Sir David Attenborough narrates video of O. coenobitus spiders hoisting shells into plants using strands of silk, then hiding in them. Wow:

(Via The Kid Should See This.)

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Michael Hutchinson
Spiders Can Fly Through the Air Using the Earth's Electric Field
A spider exhibiting ballooning behavior.
A spider exhibiting ballooning behavior.
Michael Hutchinson

Every so often, otherwise Earth-bound spiders take to the air. Ballooning spiders can travel hundreds of miles through the air (and, horrifyingly, rain down on unsuspecting towns). The common explanation for this phenomenon is that the spiders surf the wind on strands of silk, but there may be other forces at work, according to a new study spotted by The Atlantic.

In the research, published in Current Biology, University of Bristol scientists argue that Earth's atmospheric electricity allows spiders to become airborne even on windless days. To test their hypothesis, the researchers exposed spiders in the lab to electric fields similar to those naturally found in the atmosphere.

When the electric field was turned on, the spiders began to exhibit behavior associated with ballooning—they "tiptoed" on the ends of their legs, raised their abdomens, and released silk. Spiders only exhibit this behavior when ballooning. And when they did become airborne, the spiders’ altitude could be controlled by turning the electric field on and off. When the electric field was on, they rose through the air, but when it was off, they drifted downward.

This provides a potential explanation for why spiders take to the skies on certain days but not others, and how they can fly in calm, windless weather— something scientists have puzzled over since the early 19th century. (Even Darwin was flummoxed, calling it "inexplicable," The Atlantic notes.) However, the researchers note that these electric fields might not be totally necessary for ballooning—wind alone might work perfectly fine on some days, too. But understanding more about when and how spiders become airborne could help us predict when there will be large masses of arachnids flying through the skies (and hide).

[h/t The Atlantic]

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iStock
How Spiders Surf the Wind For Miles on Strands of Silk
iStock
iStock

Spiders may very well be hairy and scary, but at least they can’t fly … right? Well, that depends on your definition of flight. As The New York Times reports, new aeronautical research is shedding light on the little-understood phenomenon of “ballooning,” which lets spiders span great distances—even oceans—by riding the wind like paragliders.

Moonsung Cho, an aeronautical engineer, started researching “spider flight” after witnessing a spider being carried by the wind in Denmark. Scientists have long known that spiders sometimes use flight to evade threats or seek food and mates in other locations, but prior to this study, the physics of how it actually works remained fuzzy.

Cho and his colleagues brought crab spiders back to the laboratory and used a wind tunnel to observe their response in a controlled setting. They discovered that a spider will use its leg as an anemometer, lifting one limb to test the strength of the wind. (Their idea of perfect flying weather is a light breeze of about 7 mph.)

Then, the spider lifts up its abdomen, shoots strands of silk skyward, and lets itself be carried off into the sunset. These strands of silk are far thinner than a strand of human hair and can measure up to 6 feet long. As Live Science puts it, a strand of silk contorts when it’s caught in the wind, thus “catching air like an open parachute.” This lets spiders surf the air current, at least for a few miles.

Instances of “spider flight” have been witnessed all over the world. Residents of one Australian town reported seeing a “tunnel of webs” in the sky back in 2015. Spiders sometimes migrate en masse, and although they use the wind to move about, they can’t control where they end up. Some have even landed on islands in the middle of the ocean.

Check out this video from The New York Times to learn more ballooning.

[h/t The New York Times]

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