Small White (Pieris rapae) in Ireland

Bánóg bheag in Gaeilge. The Small White, Pieris rapae, is the commonest garden white in Ireland, present in every county and often the butterfly Irish gardeners meet first over the vegetable bed.

Identify it in four steps

1. Upperside white with a dusky forewing tip, more diffuse and greyer than the crisp black tip of the Large White.
2. Females show two black forewing spots on the upperside; males show one; both sexes have a single spot on the hindwing costa.
3. Underside hindwing pale creamy-yellow with a light greyish dusting, without the green vein tracing of the Green-veined White.
4. Wingspan 38 to 50 mm; flight is a low, quick jinking pattern across cabbage rows and garden borders.

Habitat in Ireland

The Small White is a species of gardens, allotments, farmland margins, and set-aside. Larvae feed on cultivated and wild Brassicaceae, including cabbage, kale, Wild Radish (Raphanus raphanistrum), and Garlic Mustard, and are often the caterpillar Irish gardeners find grazing brassica leaves in July and August.

Two broods a year in Ireland in most years, with a strong second brood in July and August that overlaps with Large White numbers. The species overwinters as a pupa attached to a wall, fence, or foodplant stem.

Where to see it

• any Irish urban garden with a Brassica bed: the species is a reliable garden visitor from April to October.
• Phoenix Park allotments, Dublin: vegetable plots and set-aside verges hold high summer densities.
• farmland margins across the eastern arable belt: field-edge Wild Radish supports the species between cabbage crops.

Related species

• Large White (Pieris brassicae)
• Green-veined White (Pieris napi)
• Orange Tip (Anthocharis cardamines)