California gall wasp
The California gall wasp is a small, stout brown wasp about half a centimetre long. It makes oak trees grow big round balls called oak apples on their twigs. Its babies live and grow inside these balls.
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Fun facts
Its oak apples can be from 2 to 14 centimetres across, as big as an orange.
No male California gall wasp has ever been found. The mothers lay eggs without any fathers.
In spring the galls can puff up on the twigs almost overnight.
More than 20 other kinds of insects live in or around its galls, and some birds eat from them too.
Some babies stay in the gall a whole extra year before they come out. Nobody knows why.
Most asked questions about California gall wasp
?What are the big balls on oak trees in California?
They are oak apple galls made by the California gall wasp. Its babies grow inside them.
?How big is a California gall wasp?
The wasp is only about 5 millimetres long, but its galls can be as big as an orange.
For bug experts
- Scientific name
- Andricus quercuscalifornicus
- Group
- Wasps and hornets
- Family
- Cynipidae
- Classification
- Insecta > Hymenoptera > Cynipidae
- Lives on
- North America
Where the facts come from
- Andricus quercuscalifornicus (Wikipedia, CC BY-SA 4.0): what it looks like, where it lives, what it eats, sizes and fun facts, retold in simple words.
- Picture by Fell Wraith. Public domain, Wikimedia Commons. The sticker of this bug is drawn from this picture.
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