Tiny “Crypt-Keeper” Wasps Made into Zombies by Tinier Wasps
As much as I’d love to put a rusty machete right through a zombie’s stinking, half-decomposed skull, there have so far been no confirmed cases of the dead rising again to eat our brains. To catch a glimpse of what real-life zombies are like, one has to begrudgingly look to the insect world. There are scores of examples of parasites or insects turning other insects into veritable “zombies” which live on in a state of catatonic near-death. In North Carolina last year, honeybees were discovered to have been infected by the tiny parasitic fly Apocephalus borealis, which infests live bees and causes them to behave erratically and abandon their hives. In Japan, caterpillars of the Japanese oakblue butterfly are known to secrete chemicals which turn everyday ants into zombie-like bodyguards.
The latest example of zombified insects comes from Texas, where biologists from Rice University have discovered a previously unknown form of double zombification, otherwise known as hypermanipulation. In this case, an already parasitic wasp is made into a zombie by yet another parasitic wasps. It’s wasps all the way down.
The host, the “crypt gall wasp Bassettia pallida, is already technically a parasite since it deposits its larvae into crypt-like holes bored into the tissues of trees. After the larvae are resting comfortably in their tiny “crypts,” the tinier Euderus set wasps come along and lay eggs in the soft, squishy larvae. Once the larvae mature into wasps and poke their heads out of their holes, the E. set wasps then explode from the heads and fly away to repeat the process.
According to the researchers’ published study of the wasps, this could be among the first observed cases of so-called hypermanipulation, a relatively unknown phenomenon that has only recently been discovered:
The observation that the manipulation appears to be fairly widespread may lead one to wonder—are also the manipulators manipulated? That is, how common is hypermanipulation? […] Overall, examples of hypermanipulators are rare, but are important to identify and study as any ecological impacts associated with parasite manipulation of host phenotype may be modified in the presence of a hypermanipulator.
The mechanism by which E. set is able to manipulate its host wasps is still unknown. The researchers believe there could be millions of other undiscovered parasitic wasps in the wild. It makes one wonder: just how many insects we see every day are actually the zombified slaves of other insects? Nature is terrifyingly weird sometimes.