Ballista Spider: Catapult‑Like Web Captures Aggressive Ants in Australian Rainforest

In the remote rainforests of northern Queensland, researchers have uncovered a tiny arachnid whose hunting technique rivals that of an ancient artillery piece, flinging its prey at extraordinary speeds.

The new species, belonging to the Propostira genus, constructs a cone‑shaped scaffold of silk tension lines that spring to launch the green tree ant—Oecophylla smaragdina—into its larger capture web.

In a 10‑night study conducted with high‑speed and infrared cameras, researchers observed the spider dropping from a tree canopy after dusk and attaching a silk anchor before assembling the trap.

The ant’s bite activates the mechanism, propelling the prey into the main web at acceleration levels the researchers compared to 15 g‑forces experienced by jet pilots.

Unlike most spiders, this creature targets only green tree ants, possibly drawing them out with pheromones and provoking a defensive reaction that releases a single prey into the trap.

The discovery, published in Current Biology, highlights a highly specialised evolutionary strategy that allows the spider to safely capture a defensive species and keep its garden far from the ant colony.