A newly unearthed spider species found in the tropical rainforests of Australia has surprised scientists with its unique hunting method, which involves propelling prey into the air using a spring-loaded silk mechanism. The spider, known as the “ballista spider” due to its catapulting technique, constructs a cone-shaped snare to launch green tree ants into its web.
Ajay Narendra, a biology professor at Macquarie University in Australia and a leading researcher on the study, expressed awe at witnessing the spider’s behavior firsthand. The spider, classified under the genus Propostira and yet to be formally named, was first observed by researcher Greg Anderson in 2022 in a remote rainforest in Queensland’s Cape York Peninsula.
The research team from Macquarie University traveled to northern Queensland in 2023 to study the spider’s hunting strategy. Using high-speed cameras, they spent 10 days documenting the spiders’ hunting techniques. The spiders, measuring three to five millimeters in length, are nocturnal creatures that construct intricate traps under leaves after sunset.
These spiders descend about half a meter to attach silk tension lines to create a cone-shaped structure, which is then wrapped in finer silk. Green tree ants are lured to the trap and get stuck when they bite the silk cone. The tension is released, launching the ant into the air, where it lands in the spider’s main web for consumption.
The research team observed that the green tree ants were attracted to the trap within minutes of the final silk layer being placed, indicating a possible pheromone-based lure specific to these ants. The spiders’ specialized hunting tactic is believed to have evolved as a means to capture green tree ants, known for their collective strength.
Further studies are planned to investigate the spider silk’s pheromones and their role in prey specialization. Saad Bhamla, an associate professor at the University of Colorado-Boulder, suggests that the aggressive nature of green tree ants might explain why they are targeted by the spiders. The launch mechanism of the ballista spider subjects the ants to significant G-forces, surpassing those experienced by jet pilots.
Unlike the slingshot spider, which actively uses its web to launch itself at prey, the ballista spider conserves energy in its silk trap to launch prey with force while remaining at a safe distance. The discovery of this unique hunting behavior showcases the ongoing mysteries of nature and the endless possibilities for new revelations in the field of biology.
