Today I Discovered The Soul-Sucking Wasp That Makes Zombie Cockroaches

Image: B. Schurian, MfN/ The Soul-Sucking Wasp By Popular Acclaim (2014) PlosOne

This beautiful nightmare is known as Ampulex dementor. Yes, that is a reference to the flying, robed figures from the Harry Potter universe. It's been so named because it paralyses cockroaches by stinging them in the thorax and brain, essentially zombifying them or, more colourfully, removing their soul.

How wonderful.

What it does once the cockroach can no longer resist is truly terrifying.

Ampulex dementor belongs to a group of insects known as the 'cockroach wasps' of the family Ampulicidae. This family of insects preys on cockroaches with precision and skill that surpasses even the most qualified marksman - their stingers are able to pinpoint locations within the cockroaches body that will both paralyse them and, essentially, remove their will to resist.

The wasps themselves look more like winged ants and they spend a lot of their time jumping and hopping around in the soil.

In a somewhat unique approach to taxonomy, the Dementor wasp was named by popular vote. The Museum für Naturkunde, Berlin, displayed the wasp for a period of time in 2012 and allowed museum guests to vote for their preferred name. Four options, with reasoning, were provided for the ballot and eventually Ampulex dementor won out.

It's better than Waspy McWaspFace, that's for sure.

The species is relatively new to scientists and hasn't been studied in the wild or in the lab with great regularity. Indeed, searching for scholarly articles on it returns the one paper that describes its naming process at the Museum für Naturkunde. That's it.

However, our knowledge of the Ampulicidae is largely drawn from laboratory experience with another, similar species of cockroach wasp: The emerald cockroach wasp (Ampulex compressa)

BBC's Micro Monsters filmed the entire process of the emerald cockroach wasp paralysing and larval feeding on a cockroach in the wild. The sequence sees the metallic green wasp treads toward the roach, mount it and sting it in the thorax, paralysing its front legs. Shortly after, a second sting is delivered to the roach's 'brain' - a collection of nerve cells - that delivers a toxic cocktail disabling the roach's will to live.

In this case it isn't the zombie cockroach that lumbers around looking for brains, but the aggressor wasp. Finding and controlling roach brains is key to its survival.

Once the roach is paralysed and lacking the motivation to move, the wasp drags it back to a burrow where it lays an egg on the cockroach's underside.

As the larva develops, it feasts on the paralysed-but-still-alive cockroach, releasing an antibacterial cocktail that prevents the roach from dying from infection. Inside the roach's body, the wasp forms a cocoon and the roach, after being eaten alive, finally dies. Eventually, the emerald cockroach wasp emerges from the cocoon and the roach shell to begin the process anew.

It's truly grim and magnificent. An evolutionary masterpiece.

Unfortunately, the region in which the Ampulex dementor lives is under threat, which means we may be running out of time to learn more about these varied species of killer wasp.

As Carl Zimmer eloquently puts it in one his column at National Geographic in 2015: "It’s entirely possible that A. dementor uses a soul-sucking arsenal that’s significantly different than its cousin species A. compressa. The only way we can enjoy discovering that arsenal is to make sure this species doesn’t vanish first."

While their methods may seem nightmarish, the ways in which they prey on roaches may be beneficial to humans - the antibacterial cocktail and their mind-control methods could, potentially, be useful for us when it comes to preventing diseases or unravelling the mystery of our own minds.


Today I Discovered is a daily dose of facts for Lifehacker readers - the weird, wonderful and sometimes worrying. Most of the time, it's just mind-blowing. Let us know if there's been anything you discovered lately that blew your mind!


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