Study finds spiders use electricity to fly
Darwin’s conjecture about static confirmed
published Thursday ended the long-running debate about whether spiders can use the silk they weave as a parachute to fly through the wind or if flight is powered by static electricity reacting with silk.
A study by University of Bristol sensory biophysicist Erica Morley confirmed what Charles Darwin notably observed watching hundred of spiders fly 60 miles across the ocean and land on his ship, the HMS Beagle.
Darwin surmised electrostatic force was involved. Morley and researchers backed this up by demonstrating for the first time in a lab how spiders use electrostatic forces to balloon.
When spiders launch off from the ground and float through the sky, sometimes for thousands of miles, it’s due to a “ballooning process” in which the spider raises its abdomen to the sky, spins 7- to 13-foot-long silk parachutes and flies away. A previous study confirmed that spiders fly by checking the wind and throwing out their silk parachutes at the right time. The study, however, could not account for why the multiple silk threads spiders use to balloon don’t tangle in the wind.
Morley’s research accounts for the lack of tangles and explains why spiders can fly thousands of miles even when it’s not windy. The strands don’t tangle because each is repelling off another in an electrostatic force. The study also concluded that the weather conditions are not the primary driver of when a spider balloons but rather if an electric field is present in the atmosphere.
“It is reasonable to surmise that if e-fields are ecologically relevant, spiders should be able to detect and respond to an e-field by changing their behavior to engage in ballooning,” the study said.
Researchers placed Linyphiid spiders into a box that limited air movement but mirrored electric fields naturally present in atmospheric conditions. When the field was turned on, spiders showed a “significant increase in ballooning.” The change in behavior demonstrated the spiders can detect when electricity is present.
Once the spiders were ballooning in the air, researchers turned the field off. The spiders would rapidly fall out of the air toward the ground, demonstrating spiders need the electricity order to balloon if air flow is limited.
Although wind does play an important role in the ballooning process and the subsequent miles spiders travel, this study shows that ballooning behavior is sparked by electric fields.
A new study says spiders’ ability to fly through the air is a function of how they use electricity.