New spider species in Australia uses spring-loaded snare to catch specific ant

A spider species discovered in the rainforests of north Queensland builds a spring-loaded silk snare that captures and launches a single species of ant at high speed. The spider, not yet formally named, was first observed by a biomedical scientist who also studies spiders.

A research team from Macquarie University then spent ten days and nights near Cooktown using high-speed and infrared cameras to document the behavior.

Hunting method During daylight the spider rests on the underside of leaves above foraging areas. At night it descends to attach an anchor point and constructs a cone of 15-60 vertical silk lines wrapped in thinner silk. When a green tree ant bites the cone, the structure detaches and springs upward, propelling the ant deeper into the web at accelerations comparable to those in a severe automobile crash.

The spider waits until the ant is entangled before wrapping it further.

Specialized diet Researchers noted that the spider feeds almost exclusively on the green tree ant Oecophylla smaragdina. The ant possesses chemical defenses and recruits large numbers of nestmates when threatened, making it an unusual prey choice. The study authors stated that the snare appears to be the only known spider web designed to catch one prey species and triggered by the prey itself rather than the predator.

They theorize the mechanism allows the spider to remove individual ants from trails and nests without triggering mass attacks.