The wasp known as Euderus set, or E. set, deposits an egg in the developing gall wasp’s woody haven. The young E. set eventually chews its way to freedom — through its host’s head.
Rice researchers nicknamed it the “crypt-keeper” wasp and said it’s a rare example of hypermanipulation, in which a parasite is manipulated by another parasite.
E – Gory – Emergence – Papers – Rice
E. set and its gory emergence are described in two papers led by Rice evolutionary biologists Kelly Weinersmith and Scott Egan.
The first paper, in the open-access journal ZooKeys this month, describes the new wasp species in detail. The second, released in the Proceedings of the Royal Society B, details the species’ ghoulish strategy.
Discoverers – Wasp – Set – God – Chaos
The discoverers named their wasp for Set, the Egyptian god of evil and chaos who trapped his brother Osiris in a crypt, killed him and then cut him into little pieces.
The tiny, iridescent parasite hijacks its host, Bassettia pallida, which would normally mature inside the crypt (aka the gall) and tunnel its way out to freedom in the spring. A female E. set deposits an egg into the crypt, where it manipulates the growing gall wasp, typically making its emergence hole too small.
Wasp – Head – Lodges – Hole – E
When the wasp tries to escape, its head lodges in the hole. E. set can then consume the gall wasp’s internal organs and emerge, “Alien”-like, from its head case.
“It could be the parasitoid cues hosts to excavate early, but makes them do it less well than usual,” said Weinersmith, who studies parasites. “They only go part way and then they get stuck.
Manipulation – Host – Behavior – Stories – Coolest
“That’s what I love about parasite manipulation of host behavior,” she said. “So many of the stories that have been uncovered are just as cool as the coolest science fiction movie.”