Head to head
Common Blue vs Holly Blue
Common Blue
VS Holly Blue
The common blue and holly blue are two familiar small blue butterflies of Europe, one of flowery grassland and the other of gardens and hedgerows.
| Common Blue | Holly Blue | |
|---|---|---|
| Scientific name | Polyommatus icarus | Celastrina argiolus |
| Colour | Males are bright violet-blue above, while females are mostly brown with orange spots and often a dusting of blue | A pale silvery blue |
| Underside | A grey-brown underside patterned with black-ringed spots and a row of orange spots along the edge | A pale silvery-blue underside spotted with tiny black dots and no orange markings |
| Caterpillar food | Bird's-foot trefoil and other legumes | Holly buds and berries in spring, and ivy in summer |
| Broods and winter | Often two or three broods in a year | Two broods a year, overwintering as a chrysalis |
| Habitat | Flower-rich grassland, dunes, and waste ground | Hedgerows, gardens, and woodland edges |
| Behaviour | Ants guard the caterpillars in return for their sweet secretions | Often flutters high around shrubs, hedges, and trees rather than low over grass |
| Conservation status | Least Concern, with a stable population | Least Concern, with a stable population |
Common Blue vs Holly Blue: common questions
Which blue butterfly has ant bodyguards?
The common blue, whose caterpillars produce sweet secretions that attract ants, which guard them from predators.
Why is it called the holly blue?
The spring brood lays its eggs on holly, while the summer brood lays on ivy.
Where do the common blue and holly blue live?
The common blue lives in flowery grassland across Europe, North Africa, and temperate Asia, while the holly blue lives in hedgerows, gardens, and woodland edges across the same region.