A newly found spider species in the tropical rainforests of Australia has surprised scientists with a unique hunting method that propels prey into the air using a spring-loaded silk mechanism.
Published in the journal Current Biology this week, a study details how the small arachnid constructs a cone-shaped snare to launch green tree ants into its web, earning it the moniker “ballista spider,” inspired by ancient Roman artillery.
Ajay Narendra, a biology professor at Macquarie University in Australia and a lead researcher on the study, described the behavior as “absolutely breathtaking” after witnessing it firsthand.
The spider, belonging to the Propostira genus, is yet to be formally named. Researcher Greg Anderson first spotted the spider in 2022 when he observed a green tree ant being flung into a web in a remote rainforest in Queensland.
This sighting led a team from Macquarie University to investigate further in 2023, capturing the spiders’ hunting strategy on high-speed cameras over ten days. The spiders, measuring three to five millimeters, are nocturnal creatures that hide under leaves during the day and construct intricate traps at night.
Using silk tension lines, the spiders create a cone-shaped structure that launches ants when triggered. The ants are attracted to the trap within minutes, suggesting the silk may contain pheromones specific to green tree ants.
Narendra believes this method evolved as a way to hunt green tree ants without direct confrontation due to their collective strength. Further research will focus on identifying the pheromones involved in this specialized hunting behavior.
The launch mechanism is swift, subjecting the ants to significant G-forces, surpassing those experienced by jet pilots. Unlike the slingshot spider, which uses a similar tactic, the ballista spider conserves energy in its silk trap to propel prey with force while maintaining a safe distance.
Saad Bhamla, an associate professor at the University of Colorado-Boulder, suggests the ants’ vigilance may explain their attraction to the spiders’ traps. The discovery highlights the ongoing exploration of nature’s wonders and the mysteries yet to be uncovered in the natural world.