In the Gutianshan National Nature Reserve in eastern China, researchers have discovered a new species of wasp that has a unique nest building technique.
The Deuteragenia ossarium, or the "bone-house wasp," is a cavity-nesting wasp, which means that they build their nests in either self-made holes or pre-existing tunnels. They typically consist of several brood cells (each cell contains a single wasp larva) separated by walls made plants, resin and soil. What was startling with the nests collected in China was the foremost cell was actually filled with the corpses of dead ants.
The researchers believe that the ants are being utilized because of the smell that they emit. The species of ant that was most common was the Pachycondyla astuta, an aggressive ant species with a mean sting. The thought is that predators know to steer clear of this ant, so by filling the chamber at the front of the nest the wasp larva will be masked and left alone.
The researchers say they didn't observe the the ants being killed but they are believed to have been hunted, not scavenged.
(H/T Live Science)