A recently unearthed spider species found in the tropical rainforests of Australia has astounded scientists with its hunting method that propels prey airborne utilizing a spring-loaded silk mechanism.
The spider, belonging to the Propostira genus and yet to be formally classified, constructs a cone-shaped trap to fling green tree ants into its web, earning it the moniker “ballista spider,” inspired by ancient Roman artillery. The groundbreaking study, released in the journal Current Biology this week, unveils the intricate details of this extraordinary predator.
Biologist Ajay Narendra, a key figure in the research team from Macquarie University in Australia, described witnessing the spider’s behavior as “absolutely breathtaking.” The initial discovery was made by researcher Greg Anderson in 2022, prompting an expedition to northern Queensland in 2023 to investigate further.
The tiny spiders, measuring three to five millimeters and exclusively active nocturnally, conceal themselves under leaves during the day. At night, they meticulously craft elaborate traps using silk tension lines, designed to ensnare unsuspecting green tree ants.
Upon biting the cone-shaped trap, the ants become ensnared and trigger the release of stored tension, launching them up to 30 centimeters into the air. The airborne ants land directly in the spider’s main web, where the predator lies in wait.
Notably, the green tree ants are drawn to the trap within minutes of the final silk layer being placed, suggesting the use of pheromones as a lure. This specialized silk appears to exclusively attract green tree ants while disregarding other ant species found in the vicinity.
The research team, led by Narendra, speculates that this evolutionary hunting strategy enables the spiders to target the formidable green tree ants without direct confrontation. Further investigations are planned to analyze the spider silk’s composition and potential pheromones involved in prey attraction.
The launch mechanism, occurring in a mere 42 milliseconds, subjects the ants to approximately 15 times the G-force experienced by jet pilots. This force surpasses that of the slingshot spider, which employs a similar tactic but in a more active manner.
Saad Bhamla, an associate professor at the University of Colorado-Boulder’s BioFrontiers Institute, suggests a simpler explanation for the spiders’ prey targeting abilities, proposing the vigilance and aggressiveness of green tree ants as a key factor.
The ballista spider’s ingenious method of storing energy in its silk trap, akin to a loaded spring, allows it to execute powerful launches while maintaining a safe distance from its prey. The discovery underscores the ongoing marvels awaiting exploration in nature, reinforcing the notion that there is still much to unveil in the world of science and biology.