The new species, Deuteragenia ossarium, is named after graveyard ossuaries where thousands of bones are collected.
Female wasps pounce on spider prey and sting; her venom attacks the nervous system of the spider and paralyzes it. Then she drags the body of her immobilized victim back to her nest, a tunnel in the ground or a tubular hole in wood.
A single egg is laid on the spider, and the wasp walls it up alive in a tomb of spit and soil. When the egg hatches, the wasp larva eats the (still living) spider.
They sting like crazy as well; one sting and the person drops everything and screams. And keeps screaming. The recommended advice is to “lay down and scream” so as to avoid further injury by stumbling or tripping.
This particular species has an even more creative reproductive strategy (you knew it wasn’t going to end with just that, didn’t you?):
When the experimenters reared out the larval wasps from these nests, they were a species that had never been described before. The barricade of dead ant bodies radically reduced the rate of parasitism.
Why entomb bodies of ants? “Anting” is a well known behavior for several animals, including many bird species.
It’s thought the defensive chemicals of ants act as a repellant to parasites and predators. You aren’t wearing the skin of your enemy, you’re wearing the smell of your enemy.
Top image of the related “tarantula hawk” of Ecuador via Wikimedia Commons.