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The Zombie Wasp: Morphology of Ampulex compressa, the Emerald Cockroach Wasp (Emerald Jewel Wasp)

Updated: May 9, 2023



Physical Features | Habitat and Distribution | Reproductive Habits

| Life Cycle |


The world of insects is full of surprises and wonders, and the Emerald Cockroach Wasp is no exception. Ampulex compressa, also known as the Emerald Jewel Wasp or the Emerald Cockroach Wasp, is a fascinating creature with an unusual method of reproduction. These wasps are known for their ability to control and manipulate the behaviour of Periplaneta americana, a behaviour that has earned them the nickname "zombie wasps" in the animal kingdom. In this article, we will delve into the morphology of the Emerald Jewel Wasp and explore the fascinating ways in which this creature interacts with its environment.


A. compressa can be classified as follows:

Order- Hymenoptera

Family- Ampulicidae

Genus- Ampulex

Species- compressa


Physical Appearance

This insect is a real gem, with a stunning emerald green coloration that catches the eye. Its long and slender body measures around 22-30 mm in length, and its wingspan can reach up to 50 mm. The cockroach wasp's long antennae are just as impressive, often as long as its body, and used to detect potential cockroach hosts. Their wingspan is about 40-50 mm, and their wings are transparent with slight iridescence. The wasp's eyes are large and black. They have two pairs of wings and three pairs of legs.



But don't let its beauty fool you, the Emerald Cockroach Wasp is a skilled hunter with a powerful venomous sting. The wasp's stinger is used to inject venom into the cockroach host, paralyzing it and altering its behaviour. To look at, the wasp has metallic green-blue-orange-black colours out of which the last two legs have striking orange femur. Its body is slender, antennae are coiled at the tip, and legs and wings are easy to observe when the wasp is in resting position.



Habitat and Distribution

The Emerald Cockroach Wasp is native to Southeast Asia, particularly in countries like Thailand, China, and Indonesia. The ones in the pictures were discovered in India. It can be found in a variety of habitats, including forests, fields, and gardens. These wasps prefer warm and humid climates and are the most active during the day.

But what is its social structure like? Unlike other wasps that live in colonies, the Emerald Jewel Wasp is a solitary insect. However, its reproductive habits reveal a fascinating complexity.


Reproductive Habits

The reproductive habits of the Emerald Cockroach Wasp are among the most fascinating and unique in the animal kingdom. The female wasp will seek out a cockroach host, lay a single egg on its underside, and then leave. The sting is used to momentarily paralyze Periplaneta americana to deliver a GABA rich venom twice-first in the prothorax (to paralyse front legs for one to two minutes) and second in the suboesophageal ganglion (which renders the cockroach able to walk, but not run away).


The venom has two main objectives:

  • It makes the cockroach submissive to the wasp, which will drag the cockroach, from its antennae, into its burrow and lay one or two eggs inside the living cockroach's mesothoracic leg. Later the female seals the burrow with surrounding debris.

  • It alters the behaviour of the cockroach. An aftereffect of venom injected in the sub-oesophageal ganglion is that the cockroach religiously grooms itself to ensure that the wasp progeny has a clean environment to grow devoid of growth of microbes.



When the egg hatches (after approximately three days), the larva first feeds off the haemolymph and organs inside the thoracic and abdominal cavity of the living cockroach and completes its life cycle as an endoparasitoid! Yes, you read that right, the larva will literally eat the cockroach from the inside out, keeping it alive until the wasp is ready to emerge as an adult. The adult wasp then develops after two moults and emerges from the now dead cockroach host. The newly emerged wasp will then seek out a mate and begin the cycle anew.


So why does this wasp go to such lengths to manipulate the behavior of cockroaches? It's all about ensuring the survival of its young. The wasp provides a secure and abundant food source for its developing offspring by using the cockroach as a host.

Life Cycle

The life cycle of the Emerald Jewel Wasp consists of four stages: egg, larva, pupa, and adult. After the wasp has laid its egg on the cockroach host, the egg will hatch into a larva. The larva will burrow into the cockroach's body and begin to consume its internal organs. The wasp larva will then spin a cocoon around itself and continue to develop inside the cockroach's body.

The cocooned larva will then pupate and eventually emerge from the cockroach's body as an adult wasp, having consumed the host from the inside out. Talk about a gruesome life cycle! The entire life cycle of the Emerald Jewel Wasp takes around 30 days, depending on the temperature and humidity.



In conclusion, the Emerald Cockroach Wasp is an insect that is both beautiful and gruesome, with behaviors that are sure to capture your imagination. It's their ability to turn a cockroach into a zombie host for their young, which is a testament to their complexity and adaptability.

So the next time you see an emerald green wasp with long antennae, remember that there's more to it than meets the eye.


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