Tuesday April 23, 2019
Home Lead Story Electric Fiel...

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.

0
//
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)

Next Story

Researchers Develop, New Adhesive Patch That Can Minimize Heart Attack Damage

For the research, published in Nature Biomedical Engineering, the team tested the patch with rats and showed that the patch could be effective in reducing post-heart attack damage. 

0
Heart
The researchers said the patch, which costs "less than a penny", has been optimised using a computer model of the heart to perfectly match the material's mechanical properties. Pixabay

Researchers have developed a new adhesive patch that could reduce the stretching of cardiac muscle following a heart attack.

Developed by a team of researchers from Brown University, US; Fudan University, China and Soochow University, China, the patch is made from a water-based hydrogel material and can be placed directly on the heart to prevent left ventricular remodelling — a stretching of the heart muscle.

A heart attack puts the cardiac muscle at a risk of stretching out that can reduce the functioning of the heart’s main pumping chamber.

ecg
The researchers say the initial results are promising for eventual use in human clinical trials. Pixabay

“Part of the reason that it’s hard for the heart to recover after a heart attack is that it has to keep pumping,” said co-author Huajian Gao, a professor at Brown University.

“The idea here is to provide mechanical support for damaged tissue, which hopefully gives it a chance to heal,” he added.

The researchers said the patch, which costs “less than a penny”, has been optimised using a computer model of the heart to perfectly match the material’s mechanical properties.

“If the material is too hard or stiff, then you could confine the movement of the heart so that it can’t expand to the volume it needs to,” Gao said.

“But if the material is too soft, then it won’t provide enough support. So we needed some mechanical principles to guide us,” he pointed out.

For the research, published in Nature Biomedical Engineering, the team tested the patch with rats and showed that the patch could be effective in reducing post-heart attack damage.

heart
A heart attack puts the cardiac muscle at a risk of stretching out that can reduce the functioning of the heart’s main pumping chamber. Pixabay

“The patch provided nearly optimal mechanical supports after myocardial infarction (i.e. massive death of cardiomyocytes),” said co-author Ning Sun, a cardiology researcher at Fudan University.

“[It] maintained a better cardiac output and thus greatly reduced the overload of those remaining cardiomyocytes and adverse cardiac remodelling.”

Also Read: China’s Political System Helps It To Take A Lead in Artificial Intelligence

The researchers say the initial results are promising for eventual use in human clinical trials.

“It remains to be seen if it will work in humans, but it’s very promising,” Gao said. (IANS)