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Sticker of Saint John's wort beetle
Bug card No. 3726 of 4,939

Saint John's wort beetle

Chrysolina hyperici
Eats: PlantsBeetlesGardens and meadows6 legs

The Saint John's wort beetle is a little leaf beetle that loves one plant above all: Saint John's wort. It eats the leaves of this plant and lays its eggs on it too. People even use it to stop the plant from spreading too much.

Lives in
Europe and Asia, and taken by people to other places such as North America
Top speed
about 0.5 km/h (0.31 mph)
On foot, estimate
Can it hurt you?
Harmless
Harmless. It cannot bite or sting.
What does it eat?
It eats the leaves of Saint John's wort. Its larvae eat the leaves too.
For real!Photo of Saint John's wort beetle
Picture by Francisco Welter-Schultes. CC0, via Wikimedia Commons.

How fast is it?

cool stuff

Fun facts

1

One female can lay up to 2,000 eggs.

2

Its larvae come out to eat at night and hide during the day.

3

When the larvae are big enough, they crawl into the soil to turn into beetles. Two weeks later the new beetles come out.

4

People in some countries brought it in on purpose, to eat Saint John's wort that was growing where it was not wanted.

you asked

Most asked questions about Saint John's wort beetle

?What does the Saint John's wort beetle eat?

The leaves of Saint John's wort and some of its close plant cousins.

?Why do people release Saint John's wort beetles?

To control Saint John's wort in places where the plant spreads too much.

For bug experts

Scientific name
Chrysolina hyperici
Named by
Forster, 1771
Group
Beetles
Family
Chrysomelidae
Classification
Insecta > Coleoptera > Chrysomelidae
Lives on
Europe, Asia, North America
Also known as
Lesser St. John's wort beetle, St. Johnswort beetle, Klamathweed beetle

Where the facts come from

  1. Chrysolina hyperici (Wikipedia, CC BY-SA 4.0): what it looks like, where it lives, what it eats, sizes and fun facts, retold in simple words.
  2. Picture by Francisco Welter-Schultes. CC0, Wikimedia Commons. The sticker of this bug is drawn from this picture.

If we got something wrong, sorry, we are bug fans, not a science journal. Tell us at [email protected] and we will fix it.

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