Ballista spider hurls ants into a silk catapult web in Australia

Australian researchers from Macquarie University describe a newly identified spider that uses a spring-loaded, catapult-like silk trap to catch only the aggressive green tree ant (Oecophylla smaragdina). Nicknamed the “ballista,” the spider builds a cone-shaped scaffold of tension lines, then launches a entangled ant into its web at extreme acceleration (about 15 g) when the ant bites the trap. The nocturnal predator hunts on trees in northern Queensland, potentially using pheromones to lure the specific ant while avoiding other prey. The discovery, documented in Current Biology, was made over ten nights with high-speed and infrared cameras by Ajay Narendra and colleagues from Macquarie University.