Green-veined White (Pieris napi) in Ireland

Bánóg uaine in Gaeilge. The Green-veined White, Pieris napi, is Ireland’s commonest white butterfly and, despite the name, is a wild-flower species, not a cabbage pest.

Identify it in four steps

1. Underside hindwing greenish-grey with dark grey scales aligned along the veins; the diagnostic mark that separates it from Small White.
2. Upperside forewing tip has a diffuse grey-black smudge, not the crisp black wedge of the Small White or the strong black tip of the Large White.
3. Females carry two black spots on the forewing upperside; males have one. Both sexes are pale cream rather than pure white.
4. Wingspan 40 to 50 mm; flight is a steady, low weave through damp meadow and hedge base, unlike the Large White’s stronger direct flight.

Habitat in Ireland

The Green-veined White favours damp meadow, ditch edge, woodland ride, hedgerow, and mature garden. It is more strongly tied to unimproved, flower-rich ground than the Small White and appears in numbers wherever wild crucifers persist.

Larvae feed on native crucifers including Cuckoo Flower (Cardamine pratensis), Garlic Mustard (Alliaria petiolata), and Watercress (Nasturtium officinale). The species is not a garden brassica pest; that habit belongs to Small White and Large White.

Where to see it

• Clara Bog, County Offaly: raised-bog margin ditches and Cuckoo Flower stands hold the species from April.
• Lough Neagh shoreline, County Antrim (Northern Ireland): damp lakeshore meadow and Watercress-fringed drains.
• the Slaney Valley, County Wexford: hedgerow banks and damp grassland along the river corridor.

Related species

• Large White (Pieris brassicae)
• Small White (Pieris rapae)
• Orange Tip (Anthocharis cardamines)