Crypt-Keeper Wasp, Euderus Set, Is A Newly Discovered Parasite That Kills Its Host By Eating Its Head — From The Inside Out

So far as parasites go, Euderus set is the sort of stuff nightmares, or scary movies, are made of. The newly discovered wasp was named after Set, the Egyptian god of evil and chaos.

In Egyptian lore, Set trapped his brother Osiris in a crypt, killed him and then cut the body into numerous little pieces. E. set — nicknamed the crypt-keeper wasp by researchers from Rice University, Houston, who discovered it — does not kill its brother but its host in a similar manner.

The host is also a wasp, Bassettia pallida or the gall wasp, which matures inside “crypts” in branches of trees. Once matured, B. pallida would tunnel its way through the bark and making a small hole in it, leave its crypt behind.

But if a female E. set gets to the crypt, it lays an egg in it, which manipulates (how this manipulation works is not yet understood) B. pallida to make an emergence hole smaller than it would normally. And when B. pallida tries to leave the crypt, it gets stuck in the hole. At that point, the baby E. set which has since hatched from the egg starts to eat through its host’s body, and eventually through its head, and flies away into the world outside.

“It could be the parasitoid cues hosts to excavate early, but makes them do it less well than usual. They only go part way and then they get stuck. That’s what I love about parasite manipulation of host behavior. So many of the stories that have been uncovered are just as cool as the coolest science fiction movie,” Kelly Weinersmith, an evolutionary biologist at Rice who studies parasites, said in a statement, which also made a reference to the film “Alien.”

E. set, a tiny iridescent wasp, was described in a paper earlier this month. Titled “Description of a new species of Euderus Haliday from the southeastern United States (Hymenoptera, Chalcidoidea, Eulophidae): the crypt-keeper wasp,” it was published in the journal ZooKeys, and its team of authors was led by Weinersmith and Scott Egan, who is also an evolutionary biologist at Rice.

Its behavior was described by the researchers in another paper published Wednesday. “Tales from the crypt: a parasitoid manipulates the behaviour of its parasite host” appeared in the journal Proceeding of the Royal Society B.