Lead researcher Morley pointed out that spiders aren't the only invertebrates to balloon.
However, we don't know at this point which is the dominant factor." They definitely play very important roles. She told VOA, "I think that both the electrical field and the fluid mechanics are important. Mathematician Longhua Zhao from Case Western Reserve University in Cleveland has made computer models of how spiders balloon. Spiders probably use both when taking off and navigating the skies. In nature, it makes sense for spiders to sense both the electrostatic field around them as well as wind conditions. The small hairs along the spiders' legs react not only to physical experiences like a breeze but also to the electric field. So I thought that it's possible that they might be using these same hairs to detect electric fields." "We know that they have very sensitive hairs that are displaced by air movements or even sound.
"As a sensory biologist, I was keen to understand what sensory system they might use to detect electric fields," said Morley. That's kind of what's happening with the spider silk."Ĭlearly the spiders were able to sense the local electrostatic field and respond appropriately by releasing silk, but Morley and Robert wanted to know how. "If you hold the balloon, your hair stands on end. Sheldon compared it to taking a balloon and rubbing it against your clothing. Morley told VOA that spiders only tiptoe right before they release silk draglines to fly away, in a process called ballooning.Īnd when the spiders did balloon and rise into the air, turning off the electric current caused them to drop. When the electric field was on, the spiders lifted their abdomens into the air and started tiptoeing by raising up on the very ends of their legs. The scientists placed spiders in the box and turned on the voltage, watching as the creatures reacted to the electric field. Morley and Robert created a box with a grounded metal plate on the bottom and a plate on the top that they could pass an electrical current through. So we've known for a while that electrostatics probably at least interacting with the spider, with the silk lines themselves, to keep them from getting tangled." Biologist Kimberley Sheldon from the University of Tennessee at Knoxville, who was not involved in the new research, pointed out that "though these spiders will have five or six draglines, those strands of silk do not get entangled. Some observers suggested electrostatic fields might be the reason the multiple draglines some spiders use to float don't get tangled with each other. "There have been several studies looking at how air movement and wind can get spiders airborne, but the electrostatic hypothesis was never tested," Morley told VOA. They thought spiders might sense and use electrostatic fields in the air. He thought the arachnids might be using heat-generated updrafts to take to the sky, but new research shows a totally different cause may be at play.Įrica Morley and Daniel Robert from the University of Bristol in England were interested in exploring a second explanation for the spiders' ability. Charles Darwin remarked on the behavior when tiny spiders landed on the HMS Beagle, trailing lines of silk. Since the 1800s, scientists have marveled at how spiders can take flight using their webbing.
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