Description: Wingspan 40-52mm. This is an extremely variable butterfly, but general characteristics should mean most specimens can be identified. Adults have black tips to the forewings. The underside of the hindwing is pale yellow with the veins prominently lined with diffuse green mottling. On some specimens this mottling can be seen from the upperside. Adults of both sexes of the summer brood are darker than their first brood counterparts. Females are more prominently marked and darker than males. Adults have been recorded in all months between March and October. There are two broods each year. The spring brood peaks in late April and early May and the summer brood in late July and early August. The flight period of the two broods overlaps in late June/early July.

World Distribution: This is an extremely widespread butterfly, found throughout Europe, NW Africa, Asia between 40º and 70ºN and N. America. The specific status of some populations are disputed.

Irish Distribution: This is probably the commonest butterfly in N. Ireland. Certainly away from urban areas it is the commonest white in N. Ireland. It is found everywhere in open habitats and open woodlands especially wet grassland up to 300m. It is absent from only the highest ground and most urbanised areas. It is a non-migratory species.

Ecology: Green-veined Whites inhabit loose colonies in grassland and open habitats. The adults stay within habitat but colonies mingle. Males fly within habitat searching for females. There is usually a courtship chase prior to mating. The females lay eggs on the young leaves of the foodplant which is most commonly Cuckoo-flower Cardamine pratensis but other wild crucifers are occasionally used. Adults feed frequently on flowers including Cuckoo-flower, Knapweed Centaurea nigra and Bramble Rubus fruticosus. The pupa is the overwintering stage.

Key Identification Features:

• White wings with black tips to forewings
• Underside of hindwing with green mottling along veins

Distribution Map from NBN: Pieris napi at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Pieris napi at iNaturalist World Species Observations database.