SerpApi.Org
There are a lot of interesting spider species around the world, but Australia has some real doozies. For instance, the Megamonodontium mccluskyi fossil from Australia is pure nightmare fuel because it's five times the average size of its current-day relatives, while the Australian funnel-web spider is the fastest killing spider in the world with an unexpected death rate. Scientists have recently found a brand new species that uses a remarkable hunting technique: a conical snare trap that acts like a catapult to launch prey into its web.
The new spider species hasn't been officially named yet, so the researchers from Macquarie University are referring to it as the ballista spider. However, they have determined that it's part of the Propostira genus and Theridiidae family. In a paper published in Current Biology, they describe how this new spider uses a spring-like web trap specifically for catching an aggressive species of green tree ant (Oecophylla smaragdina).
About half-an-hour after sunset, the scientist saw the ballista spider emerge from its hiding place to build a fan-shaped web. The process involves repeatedly laying an anchor point and then a tension line until there are about 15 to 60 tension strands. On the surface, the lines were fanned out and into the shape of an upside-down cone. A green tree ant approached the spring tap shortly after and bit the cone, destabilizing it and springing it into action. The tension lines quickly contracted, slinging the ant into the air and toward the spider's core web — more than 12 inches away — in a fraction of a second.
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The ballista spider uses this hunting technique only for certain prey
While the conical trap itself is an unusual hunting technique — much like the spider that dances to lure its prey — it's not the only thing about the ballista spider that's unusual. The ballista spider seemingly specializes in hunting this single prey species. To test the prey exclusivity, the researchers released other species near the cone trap, but none of them reacted to or bit the snare. The scientists think that the spider adds pheromones to lure the green tree ant workers and trigger their aggressiveness so that they attack the trap.
Another oddity about this hunting technique is that the prey triggers the snare. In fact, all other known spiders trigger their own snares when they sense prey. Macquarie University associate professor and lead author Ajay Narendra said in a press release, "This seems to be the only case where a spider's web is designed to catch a single prey species, and where the mechanism is triggered by the prey rather than by the predator."
On top of that, the ballista spider's trap stores elastic energy, which is why it's so powerful. This energy is so significant that it whips the green tree ants into the air at a peak acceleration of 139 g's, which is the equivalent of being in a fatal car wreck. What's even more impressive is that the snare can achieve this speed even though the ants' feet have adhesive pads. In the one case that the trap was triggered without an ant attached, the acceleration reached over 480 g's.
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Read the original article on Sciencing.
