Packing a Punch

Move over, Spider-Man – slingshot spiders are redefining web-slinging in the natural world.

These pint-sized arachnids, smaller than a grain of rice, use their webs not just as traps but as spring-loaded projectiles to snag prey in mid-flight, according to a new study.

Entomologist Sarah Han of the University of Akron and her colleagues discovered that slingshot spiders – scientifically known as Theridiosoma gemmosum – deploy their webs in response to the sound of insect wings.

“Spiders may be using their webs as greater sensory devices than we previously thought,” Han told NPR. “The web is kind of like the spider’s ear.”

The process is ingenious: The spider spins a web of concentric circles, pulls it into a cone shape using a tension line, and waits at the tip. When an insect flutters nearby, the spider releases the tension line, catapulting the web forward at lightning speed – up to 50 g of acceleration, or about 1 meter per second, the researchers explained in a statement.

To test the spiders’ strategy, the team tethered mosquitoes to paper strips and waved them near the webs. They also used a tuning fork vibrating at the frequency of mosquito wingbeats.

The arachnids consistently launched their webs toward the source of these vibrations, even when the insects didn’t physically touch the web. Han suspects the spiders detect prey through sound-sensitive leg hairs and vibrations transmitted through their silk.

“It’s just like instantaneous practically – a fraction of a fraction of a second,” said Han.

The discovery is not just a marvel of natural engineering but a potential source of inspiration for human technology, according to chemical engineer Symone Alexander, who was not involved in the study.

“These spiders – the geometry of their web is slightly different and it’s tensed in a different way,! Alexander told NPR. “Can we use that as inspiration for building these sensing systems in airplane wings or other materials?”