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Electric Fields Used By Spiders To Take Flight: Research

Charles Darwin remarked on the behavior when tiny spiders landed on the HMS Beagle, trailing lines of silk.

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A spider sits in her web. Researchers from England think spiders might be sensing and using electrostatic fields to become airborne.
A spider sits in her web. Researchers from England think spiders might be sensing and using electrostatic fields to become airborne. VOA

Since the 1800s, scientists have marveled at how spiders can take flight using their webbing. Charles Darwin remarked on the behavior when tiny spiders landed on the HMS Beagle, trailing lines of silk. 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.

Erica Morley and Daniel Robert from the University of Bristol in England were interested in exploring a second explanation for the spiders’ ability. They thought spiders might sense and use electrostatic fields in the air.

“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.

Some observers suggested electrostatic fields might be the reason the multiple draglines some spiders use to float don’t get tangled with each other. 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. So we’ve known for a while that electrostatics probably [are] at least interacting with the spider, with the silk lines themselves, to keep them from getting tangled.”

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. The scientists placed spiders in the box and turned on the voltage, watching as the creatures reacted to the electric field.

Reaction to current

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. Morley told VOA that spiders only tiptoe right before they release silk draglines to fly away, in a process called ballooning.

And when the spiders did balloon and rise into the air, turning off the electric current caused them to drop.

Sheldon compared it to taking a balloon and rubbing it against your clothing. “If you hold the balloon [near your head], your hair stands on end. That’s kind of what’s happening with the spider silk.”

Spiders Use Electric Fields to Take Flight: Research
Spiders Use Electric Fields to Take Flight: Research. Pixabay

Clearly the spiders were able to sense the local electrostatic field and respond appropriately by releasing silk, but Morley and Robert wanted to know how.

“As a sensory biologist, I was keen to understand what sensory system they might use to detect electric fields,” said Morley. “We know that they have very sensitive hairs that are displaced by air movements or even sound. So I thought that it’s possible that they might be using these same hairs to detect electric fields.”

This was exactly what she observed. The small hairs along the spiders’ legs react not only to physical experiences like a breeze but also to the electric field. In nature, it makes sense for spiders to sense both the electrostatic field around them as well as wind conditions. Spiders probably use both when taking off and navigating the skies.

Mathematician Longhua Zhao from Case Western Reserve University in Cleveland has made computer models of how spiders balloon. She told VOA, “I think that both the electrical field and the fluid mechanics [of air flow] are important. They definitely play very important roles. However, we don’t know at this point which is the dominant factor.”

Also read: Did You Hear about the New Species of Spiders Named After Leonardo DiCaprio, Bernie Sanders and Barrack Obama?

Lead researcher Morley pointed out that spiders aren’t the only invertebrates to balloon. “Caterpillars and spider mites, which are arachnids but not spiders, balloon as well.” Morley hopes to see others follow up her research to see if these other animals respond in a way similar to the spiders. (VOA)

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Flu Could Put You At A High Risk Of Stroke

The reason could be due to inflammation caused by the flu infection.

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In another study, the team from the varsity, found an increased risk of a neck artery tear after having the flu. VOA

Catching flu could put you at increased risk of stroke for up to a year, finds a new study.

Although the researchers are not sure the reason behind the association, the reason could be due to inflammation caused by the flu infection.

The finding adds to previous research which has suggested the flu vaccine can reduce your risk of a stroke.

For the study, the researchers from Columbia University in the US looked at the medical records of 30,912 people with an average age of 72 years who had been admitted to hospital after suffering a stroke.

The findings, which would be presented at the American Stroke Association’s International Stroke Conference 2019 in the US, showed that people had a 40 per cent higher chance of having a stroke if they had been admitted to hospital with flu-like symptoms within the past 15 days.

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For the study, the researchers from Columbia University in the US looked at the medical records of 30,912 people with an average age of 72 years who had been admitted to hospital after suffering a stroke.

“The association occurred within 15 days. That’s important for people to know because if they get the flu, they want to be on the lookout for symptoms of stroke, especially early on after the flu,” Philip B Gorelick, Professor at the Michigan State University in the US was quoted as saying by Daily Mail.

In another study, the team from the varsity, found an increased risk of a neck artery tear after having the flu.

Neck artery tears, formally called a cervical artery dissection, happens when one of the large blood vessels in the neck is damaged, causing blood clots to develop.

It is a leading cause of stroke because it affects the blood supply to the brain, reported Daily Mail.

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Influenza leads to serious and potentially life-threatening complications such as pneumonia, sepsis and heart disease, the study noted. VOA

The study, which will be presented at the same conference, found 1,736 instances of flu-like illness preceding cervical artery dissection.

Also Read: Higher Consumption of Fruits, Vegetables May Lower Death Risk in Dialysis Patients

“Cervical or neck dissections make up about two per cent of all strokes and up to 25 per cent of strokes in persons who are under 45 years of age. So this is specifically important to people who are in that under 45 age group, but not exclusively,” said Gorelick.

Influenza leads to serious and potentially life-threatening complications such as pneumonia, sepsis and heart disease, the study noted. (IANS)