Crown of Thorns Wasp: Essential Facts and Intriguing Insights

The Crown of Thorns Wasp, also known as Acanthaster planci, is a fascinating marine creature that has captured the attention of both biologists and casual observers alike. Named for its star-shaped body covered in venomous spines, this wasp plays a significant role in the life cycle of coral reefs.

Reaching sexual maturity at the end of their second year, female Crown of Thorns wasps can produce an impressive 60 million eggs per spawning, making them prolific reproducers. Their reproduction process involves the simultaneous release of eggs and sperm into the water, resulting in an abundance of free-swimming larvae that will eventually settle onto a reef.

As a predator, the Crown of Thorns Wasp primarily feeds on coral polyps, providing a natural balance within reef ecosystems. However, in some situations, their population can explode, leading to widespread destruction of coral reefs. This boom-and-bust cycle can have significant consequences for the health and diversity of these important marine habitats.

Crown of Thorns Wasp Overview


The Crown of Thorns Wasp is an insect belonging to the family Stephanidae. They are easily identified by their distinct features, including:

  • A long, slender body
  • Prominent spines on their thorax resembling a “crown of thorns”
  • Ant-like appearance


Crown of Thorns Wasps are found in various environments, mostly in:

  • Tropical and subtropical regions
  • Forested areas

They thrive in locations with an abundance of dead or decaying wood, which serves as a breeding ground for their larvae.


Crown of Thorns Wasps vary in size depending on the species, with lengths ranging from roughly 3/16 inches for smaller species, like Callirhytis gall wasps, up to 1 1/2 inches for larger species, such as wood wasps in the family Siricidae12.

Wasp Species Size Range
Callirhytis gall wasps1 ~3/16 inches
Wood wasps (Siricidae) 2 1/2-1 1/2 inches


Crown of Thorns Wasps are widely distributed across the globe, with species present in various regions, including:

  • Central and South America
  • Africa
  • Southeast Asia
  • Oceania

Overall, these wasps are a fascinating group of insects with striking features and a wide distribution across different habitats.

Lifecycle and Behavior

Ovipositor and Stinger

  • Ovipositor: The Crown of Thorns wasp, also known as Megischus bicolor, is a parasitoid wasp belonging to the Hymenoptera order. Females possess a long, needle-like ovipositor, which they use for laying eggs.
  • Stinger: Males of this species do not have an ovipositor, and neither sex possesses a stinger.


  • Adults: Both adult males and females feed on nectar from flowers as their primary food source.
  • Parasitism: Female Crown of Thorns wasps use their ovipositor to lay eggs inside or on the bodies of other insects, such as spiders. The larvae feed on the host, ultimately contributing to its death.


The lifecycle of Crown of Thorns wasps mainly revolves around their parasitic behavior:

  1. Egg-laying: Females lay their eggs in or on host organisms using their ovipositor.
  2. Larval development: The wasp larvae develop within the host, feeding on its tissues.
  3. Adult emergence: The fully-grown larva leaves the host, pupates, and eventually emerges as an adult wasp.

Season: The exact seasonality of Megischus bicolor is not well-documented due to its rare occurrence in the entomology field.

Features Male Female
Ovipositor Not present Long, needle-like
Stinger Not present Not present
Primary food source Nectar from flowers Nectar from flowers
Role in parasitism None Lay eggs in/on host organisms

Interaction with Crown of Thorns Plant

Euphorbia Milii

Euphorbia milii, also known as the Crown of Thorns plant, is a popular houseplant and garden feature. It has spines that may cause discomfort or injury to curious children and pets. Some key characteristics include:

  • Bright flowers
  • Low water requirements
  • High light conditions
  • Well-drained soil necessary
  • Toxic sap

This plant can be harmful to pets and children, so it’s essential to keep it out of their reach.

Succulents and Cactus Care

Crown of Thorns is a succulent, so its care is similar to that of cacti. Here are some care tips:

  • Watering: Allow the soil to dry out between waterings
  • Light: Place in bright, indirect sunlight
  • Soil: Use well-draining soil to avoid root rot
  • Fertilizer: Apply a balanced fertilizer during the growing season
  • Pruning: Remove dead or damaged growth regularly

When comparing Crown of Thorns plants to other succulents and cacti, consider the following:

Feature Crown of Thorns Other Succulents & Cacti
Light Requirement Bright Varies
Watering Moderate Varies
Soil Type Well-draining Well-draining
Pruning Yes Varies

Crown of Thorns plants are an attractive and unique addition to your indoor or outdoor garden. However, be cautious of its potential hazards when growing it around children or pets.

Precautions and Safety

Sharp Thorns

Crown of Thorns Wasp plants have sharp thorns on their stems and branches that can easily pierce your skin, so it’s important to wear gloves and long sleeves when handling them. If you’re growing them in a container, choose one that is shallow and wide, to minimize the risk of injury when watering or repotting.

For example, while handling the plant:

  • Wear thick gloves
  • Use long-handled tools
  • Avoid placing the plant in high-traffic areas

Irritate the Skin

The sap of the Crown of Thorns Wasp plant can cause skin irritation if it comes into contact with your skin. Be cautious when handling the plant, and wash your hands thoroughly if you do come into contact with the sap.

To minimize skin exposure:

  • Wear gloves and long sleeves
  • Immediately wash exposed skin with soap and water

Care Tips for Crown of Thorns Wasp Plants

These plants are quite hardy and can be grown both indoors and outdoors, but there are a few factors to consider when caring for them:

  • Soil: Crown of Thorns Wasp plants prefer well-draining soil with a pH range of 6 to 7.
  • Water: Allow the soil to dry out between waterings, and avoid letting the plant sit in standing water.
  • Light: They need at least 6 hours of bright, indirect sunlight daily.
  • Fertilize: Feed your plant with a diluted liquid fertilizer every 4-6 weeks during the growing season (spring and summer).
Indoor Care Outdoor Care
Place near a bright window Plant in a sunny spot
Keep away from drafts Protect from frost
Use a well-draining container Amend soil with organic matter

Remember to always take precautions with the sharp thorns and sap when handling your Crown of Thorns Wasp plant.


  1. 2

  2. 2

Reader Emails

Over the years, our website, has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Probably Crown of Thorns Wasp


Some sort of Sabre Wasp?
Location: Austin, Texas
November 20, 2010 11:53 pm
Found this little guy on my back porch in November in good old Austin Texas. Might have had wings, if it did, then they were straight with it’s back. It was about 2 inches long, and though it is hard to see, the tip of it’s tail (?) is white. Just wanted to know if you guys knew what it was and if it stings (so I can tell my children not to try and catch it). The picture attached is the same bug, just two pictures taken with a bad camera haha.
We did not kill this bug.
Thanks so much.
Signature: Have fun, Amelia B.

Crown of Thorns Wasp

Dear Amelia,
Sabre Wasp is a name used for Ichneumons in the U.K., though that name is not often used in North America.  Your wasp is a Stephanid Wasp in the family Stephanidae based on our research on BugGuide which indicates:  “Odd little wasps, resemble ichneumons.
”  BugGuide also notes that they are “Parasitoids of wood boring beetles and wasps.”  We do not believe they sting.  Like other parasitic hymenopterans with long ovipositors, though the organ resembles a stinger, it is quite specific to its function of laying eggs on or near the host.  We believe your individual is most likely the Crown of Thorns Wasp, Megischus bicolor, though your photos do not contain enough detail to be certain.  According to BugGuide:  “The ‘crown-of-thorns’ on the head is thought to help the adult emerge from its pupation site.


  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

Leave a Comment