European glow-worm
Despite the name, a glow-worm is a beetle, not a worm; only the wingless female glows, and flying males use her light to find her in the dark.
| Where | Grassy banks, hedgerows and old grassland |
|---|---|
| Size | 15 to 25 mm body length |
| When | June to August |
Despite its name, the European glow-worm is a beetle rather than a worm; the male looks like an ordinary brown beetle and can fly, while the wingless female resembles a larger, darker version of her own larva.
Only the female glows, lighting the rear of her body for just a few nights each summer to draw in flying males, and the adults that result live for only two or three weeks.
Traits
Habitat
Grassland
Colour
Brown, Yellow
Active
Night
To people
Its glow is a mating signal, not a warning, and the beetle is harmless, with no bite or sting.
Activity through the year
Often confused with
Much smaller at about 7 to 10 mm, with a female that glows only faintly from underneath when disturbed rather than shining steadily to attract mates, and a flightless male.
Questions
Is the European glow-worm dangerous to people?
Its glow is a mating signal, not a warning, and the beetle is harmless, with no bite or sting.
When can you see the European glow-worm?
The European glow-worm can be seen from June to August, at night.
Plate retouched from a museum specimen photo by Uno Roosileht, Estonian Museum of Natural History, CC BY 4.0, GBIF Licence
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Last updated 2026-09-26. Every entry is checked against published sources.