Aug 28

The Killer Brain Surgeon: Emerald Cockroach Wasp

From a piece of rotting wood in a forest in North America comes a cockroach. It’s an ancient yet typically loathsome insect that likes to invade our homes, eat our food and spread disease. Today, however, it’s minding its own business – it’s on the lookout for some food, preferably some decaying organic matter. As it scurries about, it doesn’t notice the small, glittering, emerald-green wasp that lands nearby. Suddenly, the wasp – a female – pounces and grabs hold of the cockroach, injecting it on its underside with venom. The cockroach’s fate has now been sealed; though it may yet live for several more days, it is destined to die a grisly death.

The emerald cockroach wasp, to give this attacker a name, has only delivered a small dosage of venom; just enough to temporarily paralyse the cockroach’s front pair of legs so that it cannot run away. Now, whilst the cockroach is incapable of resisting, the wasp administers its second, much more vital, sting. With the skill and precision of a trained brain surgeon, she carefully inserts her stinger into the cockroach’s head and delivers another dose of venom to a very specific region of the cockroach’s brain.

Zombie Cockroach

The paralysis from the first sting soon wears off but the cockroach doesn’t try to escape. If anything, it stands there quite contentedly and grooms itself. This is because the venom from the second sting has affected the cockroach’s escape reflex, so even if it wanted to fight back or try to escape, it is now unable to. Bear in mind that the cockroach is, by this point, in no way paralysed. It is just completely and utterly relaxed, becoming more lethargic and apathetic as time goes on.

Unbeknownst to the cockroach, it has become the sole item on the wasp grub’s menu. The female digs a separate burrow for every one of her eggs and provisions each with a juicy cockroach. A dead cockroach, however, would have putrefied and decayed by the time the larva would have hatched, so the female must store the cockroach whilst it is still alive.


Photo: Jen R

The wasp is too small to carry the cockroach back to her burrow so she instead must ‘walk’ it back as if it were a pet. Indeed, the cockroach is now so docile that she can use the cockroach’s antennae as a leash to direct it. Once back at her lair, the emerald cockroach wasp lays a single egg on her captor and then seals the entrance to the tunnel. This is not to prevent the cockroach from escaping – it has no urge to – but rather to protect the cockroach and the wasp egg from predators outside.

The wasp larva that hatches from the egg will discover it has a nice supply of living food directly beneath it. Even as the larva tucks into its meal, the cockroach does not attempt to dislodge it. Soon, the larva enters the cockroach’s body and starts to consume its internal organs, eating them in an order that guarantees the cockroach will stay alive until the larva is ready to enter its pupal stage. All the while, the poor cockroach sits tight and occasionally grooms itself. Eventually, as the voracious feeding of the wasp takes its toll, the cockroach dies.

The wasp, meanwhile, spins a cocoon for itself within its dead host. Four weeks later, the adult emerges from the lifeless and dried husk of the cockroach and digs its way out of the tunnel to enter adult life. Its sole purpose now? To kill a great many cockroaches. In the most sadistic way possible.


  1. That is so cool – but also really really creepy. Someone should make a bad sci-fi movie about those wasps attacking humans!

    1. I’m sure the people who made Mega Piranha and Sharknado will get round to it eventually

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