Blue jewel bee, face

Parasitic Tale: The Jewel Wasp and its ‘Zombie’ Cockroach

The scientific name of the creature is Ampulex compressa. The common name is the Jewel Wasp, or in Bengali, it is known as “Jewel Bolta  (জুয়েল বোলতা).” It is mainly found in the African and Asian tropics. Its length is around one inch or slightly smaller. The exterior of its body has a beautiful coloration. Though it may look like an ordinary wasp, it is far from it. How does a tiny wasp become a master manipulator of another organism?

The fascinating story unfolds as follows: The Jewel Wasp searches for a suitable host, flying around in search of a cockroach. Once it finds one, it stings the cockroach, injecting a venom that paralyzes its front legs. It then guides the helpless cockroach to a burrow, where the wasp lays a single egg on its abdomen and seals it. The venom prevents the cockroach from escaping or defending itself.

A wasp offspring coming out from cockroach body. Source

Afterward, the wasp’s larva hatches from the egg and starts feeding on the living, paralyzed cockroach. Remarkably, the wasp larva avoids critical organs, ensuring the cockroach stays alive as long as possible. As it grows, it devours the non-essential parts of the cockroach, avoiding vital organs until the time is right.

Once the larva is ready to pupate, it delivers the final blow. It carefully eats into the cockroach’s brain, secreting chemicals that manipulate its behavior. This manipulation compels the cockroach to stay close to the wasp’s burrow and protect it as if it were its offspring. The cockroach becomes a “zombie slave,” acting solely to benefit the wasp’s offspring.

The wasp’s larva then pupates within the cockroach’s body, safe and protected, until it eventually emerges as an adult wasp, leaving behind the now-dead cockroach.

The entire process is a testament to the incredible complexity and precision of nature’s adaptations and interactions. It showcases the wasp’s ability to control another creature’s behavior for its benefit, a mesmerizing display of the natural world’s wonders.

Zombie maker and its victim. Source: National Geographic Society.

What advice did the wasp give to the cockroach? Once inside the burrow, the wasp carefully lays its eggs on the cockroach’s abdomen and instructs it to take care of the eggs. The cockroach might say, “Yes, sir!”, follow the command, and protects the wasp eggs. The cockroach keeps the eggs safe until the wasp larva hatches. At this stage, the larva resembles a tiny caterpillar and stays inside the cockroach’s body, feeding on the available nutrients. The cockroach doesn’t show any discomfort or resistance, allowing the larva to provide on it without any trouble.

This phase continues for about a month. As the larva grows more prominent, it constructs a cocoon-like structure around itself. Inside this cocoon, its eyes degenerate, its body undergoes rearrangement, and wings start to form. Despite being gigantic, the wasp remains inactive and unaware of its surroundings. The final moment arrives, and the cocoon rings the farewell bell of the wasp. The fully transformed adult wasp emerges and breaks free from the burrow, leaving behind the lifeless cockroach. The wasp then flies off in search of another cockroach of the opposite gender to begin the extraordinary and terrifying cycle again.

The process you’ve just read is not a fictional tale; it happens every day, not just in this part of the world but throughout the universe. Scientists have observed and marveled at this incredible phenomenon. They have embarked on research and studies to understand how such a miraculous event occurs. Once you grasp the entire story, you might be fascinated by the Jewel Wasp!

Place of two stings, and their function. Source: CBC.

Let’s return to the beginning—when the jewel wasp begins its stinging ritual. However, the wasp doesn’t act hastily; it carefully stings the cockroach with just two stings. Just like you know the back of your hand, the jewel wasp seems to understand the intricacies of the cockroach’s neural system. 

The first sting goes to the WRG (Walking Rhythm Generator) spot in the cockroach. From the name itself, you can guess that connected neurons control their movements, and the wasp receives signals from there, indicating that it’s time to move in that direction. The stings block the neurons’ channels in the roach. Consequently, a neurological imbalance is created; although the cockroach wants to flee, it loses coordination and control over its legs. 

It’s an incredibly intricate pharmacology—a similar method is used to treat river blindness! A particular type of parasitic worm is responsible for this disease, and as a countermeasure, a medicine called Ivermectin is used, which also effectively paralyzes the worm. Scientists discovered this method in the 1970s; interestingly, the jewel wasp has been using this technique for thousands of years!”

Now let’s delve into the story of the second sting. The second sting hits the cockroach’s brain in two places. As you can see in the picture, the first sting occurs at the SEG spot. The wasp encounters some resistance there, and for a moment, venom is discharged. But then it targets the BR spot and delivers another sting, again discharging toxin. This technique is similar to what is done in medical science and is called stereotactic drug delivery. To carry out this intricate and delicate process, the patient (the cockroach) must be placed inside a large metal frame, and the drug’s progress must be continually observed using a computer screen. Scientists believe the wasp’s specific second sting is related to some specialized neurons that can guide it to precisely target the cockroach’s brain and determine the correct route.

By performing such a delicate and subtle operation, the wasp can attack and disable the genuine location of the cockroach’s brain (and inject venom) with precision! Once the wasp accomplishes this, the cockroach relinquishes all control and submits to the wasp’s domination!

The remarkable and intriguing relationship between the wasp and the cockroach remains primarily unknown, even though we have been presented with many wonders. Knowing this, can you not enjoy and marvel at this unique and fascinating interaction?


This article is inspired by Carl Zimmer’s TED Talk titled “Parasite Tales: the jewel wasp’s zombie slave.” Carl Zimmer is a prominent figure in popular science writing, mainly known for his ability to discuss complex scientific topics in an accessible manner. His statement was made ten years ago, in 2013. Since then, science has progressed significantly, and although scientists haven’t entirely unraveled the mystery behind the Jewel Wasp and the cockroach’s parasitic interaction, they have discovered quite a bit about it. Delving deeper into the subject would make the article longer but also risk losing its easy-to-understand appeal. For the curious reader, I have mentioned a few additional sources here:

1. The science writer and researcher Arifat Rahman’s comprehensive scientific article “Prakritir Dushshwapno – Monchoshok” (Nature’s Nightmare – Mind Sucker).

2. The Scientific American article titled “How a Wasp Turns Cockroaches into Zombies.”