Video Spiders can detect the Earth’s electric field, and use it to lift off and fly through the air, according to new research.
The creepy creatures raise their legs and point their bulbous bodies to the sky before shooting lines of silk, using the material to float away in a gentle breeze. The process known as ballooning can carry them huge distances, hundreds of kilometers away, and they have even been recorded landing on ships sailing in the middle of the ocean.
Here's a quick video that show the creatures ballooning away.
It was previously thought that the pull of the wind drags the spiders away, however researchers at the University of Bristol, in England, believe that’s not the only force in play.
“We find that the presence of a vertical [electric field] elicits ballooning behavior and takeoff in spiders,” Erica Morley, a postdoctoral senior research associate in sensory biophysics, and Daniel Robert, a professor of bionanoscience, wrote in a paper published in Cell on Thursday.
The secret to airborne arachnids is down to a set of hairs known as trichobothria that cover their eight legs. Trichobothria can sense the Earth’s electric field and the difference in electric potential between the Earth’s positively charged atmosphere and negatively charged surface.
It's raining arachnids
Thunderstorms flood the skies with electrical charge to create an atmospheric potential gradient. On a clear day it can reach 100V per meter, on a stormy day this can rise to 10 kilovolts.
Spiders use this to their advantage. The silk threads spun from their bodies and accumulates a net negative charge that repels the negative charge on Earth’s surface to propel into the air.
The researchers placed Erigone spiders, a species native to North America with black shiny bodies and orange legs, into a box wedged in between two metal plates connected to a power supply.
When the plates were electrically charged, the spiders started to poke their legs into the air and stuck out their abdomens, a stance known as tiptoeing. It is observed before ballooning. When the power was turned off, the creepy crawlies stopped tiptoeing.
“The next step will involve looking to see whether other animals also detect and use electric fields in ballooning. We also hope to carry out further investigations into the physical properties of ballooning silk and carry out ballooning studies in the field,” said Morley. Spider mites and caterpillars are also known to use ballooning as a mode of travel. ®