January 26, 2017
by Brett Smith
Researchers have found a new wasp species with a life cycle so unpleasant; they named it after Set, the Egyptian god of evil and mayhem.
Indigenous to the southeastern United States, the wasp, which scientists nicknamed the crypt-keeper, lays its egg within the small, wooden compartments a different wasp species, the gall wasp (Bassettia pallida), builds inside live sand oak trees.
As soon as the egg hatches, the E. set larva digs into the other wasp and takes control of its brain, compelling it to tunnel out of the tree, a task the crypt-keeper has a hard time doing by itself.
In a final cruel twist, the E. set larva then causes its host to punch out a hole not quite big enough for it to escape. After the bigger wasp is stuck in the hole it’s burrowed, the crypt-keeper eats its host from within, finally erupting from the host’s head and out into the world.
The wasp and its insidious behavior was detailed in two recently published papers: one in the journal ZooKeys and the other in the Proceedings of the Royal Society B.
How to study such an insidious creature
To see how effective E. set could tunnel on its own, study researchers taped slender strips of bark over the dead heads of the host wasp and waited. The trials revealed the crypt-keeper was around three times more prone to perish in the crypt if it had to burrow through both the head and the bark. The experiment revealed just how much the crypt-keeper needs a host.