In the dead of night, a predator lays its traps in the rainforests of Queensland, Australia. It spins silky, spring-loaded webs, appears to coat them with a tantalizing, yet enraging scent, and then waits. Its prey comes along.
The victim rushes that way, becomes aggressive and bites the offending web. The trap snaps, and the prey catapults through the air — right to where its hunter has been waiting.
This hunter is a newly discovered spider, and scientists are for now calling it the ballista spider, after a crossbow-like weapon from ancient Rome. Its prey is an ant. And the unusual springy snare.
It is perhaps the first known example of a spider setting a trap whose mechanism is triggered by the prey itself, as described in a study from the journal Current Biology.
The discovery process began several years ago, when Gregory Anderson, an author of the study, happened upon the spider’s cone-shaped webs.
He shared the find with a small group of researchers, who “immediately thought this was absolutely bizarre and needed investigation,” said Ajay Narendra, a sensory biologist at Macquarie University in Australia who was part of that group.
The team trekked into the remote rainforests of the Cape York Peninsula in Australia to watch the spiders with high-speed cameras and infrared lights, and to collect samples of the springy silk. In total, they recorded five of the fast-moving traps on film.
“We spent several nights watching and filming these spiders build their webs and hunt green ants,” Dr. Narendra said. “We had to film at 5,000 frames per second to visualize” the hunting strategy, he added.
(After calculations, they found that the trap launched ants faster than 1,300 meters per second squared. ) We are having trouble retrieving the article content. Please enable JavaScript in your browser settings. Thank you for your patience while we verify access.
If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times. Thank you for your patience while we verify access. Already a subscriber. Log in. Want all of The Times. Subscribe.
