Mustard White, Pieris napi

Mustard White

Pieris napi

Above, this species is a plain white butterfly with no dark spots. Below, the summer form is solid white, but the spring form has darked veins beneath and often has a yellowish tinge to the hindwing and forewing tip.

Mainly moist woodlands where a variety of species of mustards, their host plants, occur.

Overwintering Strategy:   Chrysalis

This species has two broods. The first flies in late April through early June, and the second flies through July and early August.

Caterpillar Host Plants:
Rock Cress (Arabis species), Spring Cress (Cardamine species), Toothwort (Cardamine or Dentaria species)

The Mustard White occurs throughout northern Wisconsin, but becomes increasingly less common to the south. The larval stages feed on a variety of plants from the mustard family, but unlike the Cabbage White, which feeds on domesticated plants, the Mustard White feeds mainly on native species.

Overwintering Strategy

Two-way migration: Adult migrates from Wisconsin to Central Mexico
Small migration: Adult migrates from Wisconsin to southern US
Immigrant: Adult migrates into Wisconsin from warmer areas and don't fly south in winter
Adult Butterfly: Hibernates overwinter as an adult butterfly
Eggs: Eggs laid on stems, twigs or foot plants overwinter in diapause
Caterpillar: Caterpillars make nests on the base of plants and hibernate until spring
Chrysalis: Caterpillars shed their last skin, form a chrysalis and enter diapause.

For more information, read: Where Do Butterflies Go In Winter?

Further Information:   

 Design A Butterfly Garden
 Take The Butterfly Quiz
 Monarch Life Cycle
 Butterflies and Moths of North America
 Southern Wisconsin Butterfly Assn (NABA)
 The Butterfly Site

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