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Biodiversity Blog


All things creepy: parasitism pt 5, crypt keepers

Euderus set
The crypt keeper (Photo from paper by Scott P. Egan, Kelly L. Weinersmith, Sean Liu, Ryan D. Ridenbaugh, Y. Miles Zhang, Andrew A. Forbes. Creative Commons.)

Talk about a nightmare of a roommate.

Imagine yourself to be a larvae of gall wasp, the species Bassettia pallida more specifically. You are inside the gall of an oak tree, a gall that formed as a reaction to your mother laying an egg in the stem of the host tree. This little smooth gall, also known as a “crypt,” has kept you safe from the elements and any enemies, so you think. There is something else in the gall with you, or even inside you. The crypt keeper.

The crypt keeper (Euderus set) is a tiny chalcid wasp from the Eulophidae family. Like your own wasp mother, the female crypt keeper also laid her egg, but inside the gall you call home. Your wasp “roommate” has taken it upon itself to manipulate you to speed up your development without killing you. Not yet.

With adulthood suddenly arriving months earlier than normal, it’s time for you to leave your gall and greet the bright world. To do that, you begin to chew away at the gall interior when suddenly, you stop. Your head is caught. The crypt-keeper is to blame. It has been controlling you this whole time after all. Now firmly in the driver’s seat, it makes its way through you, into your head and chews it way out. So much for seeing that bright new world.

This is a rather interesting example of a parasitoid parasitizing a parasite. Try to say that five times in a row.

The crypt keeper is one of the few parasitoids that isn’t terribly choosy when finding a host, parasitizing wasps from five different genuses. However, it is picky on which gall it will oviposit (lay eggs). Mama wasp chooses small, smooth, non-woody galls that aren’t covered with spines or other growth. Since energy conservation is such a big part of survival, it’s thought that the crypt keeper takes advantage of the host doing all the hard work of chewing an exit, so all it has to do is eat its way out to freedom. Crypt keepers that have to make their way out on their own are three times more likely to die inside the gall.

The wasp was described in 2017, and named after Set, the Ancient Egyptian God of evil and chaos. Sounds like a pretty fitting name.

Read our other Parasitism Halloween Blogs

Part 1: mermithids and earwigs

Part 2: the corpse lily

Part 3: the tongue biters

Part 4: mite pockets


Frederick, Eva. “‘Crypt keeper’ wasp brainwashes far more victims than thought.” Science. September 24, 2019.

Klein, JoAnna. “There are Parasitic Wasps, and Then There’s the Crypt-Keeper.” New York Times, September 27, 2019.

Weinersmith, Kelly L et al. “Tales from the crypt: a parasitoid manipulates the behaviour of its parasite host.Proceedings. Biological sciences vol. 284,1847 (2017): 20162365. doi:10.1098/rspb.2016.2365

Wessel, Lindzi. “Crypt keeper wasp is a parasite of a parasite.” Science. January 24, 2017.

All things creepy: parasitism pt 4, mite pockets
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