Scientists Crack The Mystery Of How Spiders Fly On Windless Days — Hint: It Involves Electricity

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Spiders are surprisingly good aviators, and that’s been known for quite some time now. In fact, as the Inquisitr recently reported, German scientists have written a study detailing how crab spiders have learned to harness the power of the wind and use it to deploy giant silk parachutes that carry them for hundreds of miles into the air.

This behavior is described as ballooning and helps spiders not only move around from place to place but also evade predators, fly the nest as hatchlings to avoid getting eaten by siblings, and even find a mate.

But the curious thing about ballooning spiders — as if paragliding arachnids weren’t enough of an oddity — is that they have been shown to take off when the wind is a mere small breeze or even when it’s lacking altogether.

At the same time, there’s also the mystery of how heavier arachnids, such as the crab spiders themselves, are able to lift off into the air on just a handful of silk strands.

As it turns out, their secret is atmospheric electricity, reports the University of Bristol in the U.K.

According to a new study published by the British researchers in the journal Current Biology, spiders are able to detect the Earth’s electric fields and use natural electrostatic forces in the atmosphere to navigate the skies.

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These forces are similar to the electrostatic energy that makes your hair lift up when you rub a balloon on your sweater and then touch it on your head, notes Science Alert.

Navigating The Sky

“When one thinks of airborne organisms, spiders do not usually come to mind. However, these wingless arthropods have been found four kilometers [2.5 miles] up in the sky, dispersing hundreds of kilometers,” Erica Morley and Daniel Robert, both from the University of Bristol, write in their paper.

The researchers believe that the arachnid aviators are pulling this off thanks to their trichobothria, sensory hairs that move in response to electric fields. The spiders are thought to use these specialized hairs to detect the Atmospheric Potential Gradient, an electrical circuit that exists between our planet and its upper atmosphere.

Morley, who is an expert in sensory biophysics, explains what led her to this conclusion.

“Many spiders balloon using multiple strands of silk that splay out in a fan-like shape, which suggests that there must be a repelling electrostatic force involved.”

To test out their theory, the pair conducted a lab experiment on several Linyphiid spiders (pictured above), in which they exposed the arachnids to electric fields similar to those found in nature.

The scientists observed that, when they switched on the e-field in the lab, the spiders assumed a tiptoe stance, moving upwards to prepare for liftoff. Similarly, when the researchers switched off the electric field, the arachnids resumed their normal position, moving downwards.

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“Previously, drag forces from wind or thermals were thought responsible for this mode of dispersal, but we show that electric fields, at strengths found in the atmosphere, can trigger ballooning and provide lift in the absence of any air movement,” said Morley.

This proves that aviator spiders don’t need wind to become airborne; all it takes is a little electricity to turn on their flight engines and activate their Spidey senses.