Mustard White, Pieris napi

Mustard White

Pieris napi

Description:
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.

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

Overwintering Strategy:   Chrysalis

Flight:   
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)

Notes:   
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
 WisconsinButterflies.org
 Southern Wisconsin Butterfly Assn (NABA)
 The Butterfly Site

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