New York Natural Heritage Program
West Virginia White
Pieris virginiensis W. H. Edwards, 1870
Insects

Identifying Characteristics [-]
The West Virginia white is a small, white butterfly with generally unmarked wings above. The wings are translucent or semi-translucent, the forewing is rounded, the veins on the hindwings are indistinctly lined with brown or gray, and there is a lack of any yellow tinting on the undersides of the wings. Overall size varies from 1.8-2.1 in. (46-54 mm). This species has a low, weak flight. Caterpillars are yellow-green with a green stripe along each side (Opler and Krizek 1984, Opler and Malikul 1992).

Characters Most Useful for Identification [-]
The color and pattern on the upperside and underside of the wings is often the best means of identification for butterflies and serves to distinguish the West Virginia white from the species it may be most easily confused with. Inew New york these generally would not occur together, but Pieris napi is less translucent, brighter and has the wing veins much more strongly darkened.

Best Life Stage for Proper Identification [-]
Adult butterflies are usually more easily identified than their larvae or their pupae; although the identification of caterpillars is now more possible thanks to the completion of several new field guides and other publications including Wagner (2005), Wagner et al. (2001), and Wagner et al. (1997). A pierid larva on Dentaria would probably be this species but see Allen et al. (2005) to rule out the Cabbage White (Pieris rapae).

Behavior [-]
West Virginia white butterflies fly largely within their woodland habitat and are hesitant to cross open fields (Cappuccino and Kareiva 1985) or any unshaded habitat. Within the woods, they fly with a weak flight, low to the ground, on warm, calm, sunny days in early spring. Newly emerged males will seek moist areas near streams or the damp margins of woodland roads (Cappuccino and Kareiva 1985, Opler and Krizek 1984).
West Virginia White Images
click to enlarge
The Best Time to See
Throughout its range the West Virginia white has just one brood (univoltine) which flies in the early spring and the flight season is fairly short in duration. In the northern portion of the range, adult flight dates typically range from late April to mid June (Opler and Krizek 1984). The majority of records for New York reported in recent years are from late April to mid May with a smaller number of records from early April, late May, and rarely, early June (Fiore and Wallstrom 2003, 2004, 2005, New York Natural Heritage Program 2006). The caterpillars complete feeding by early summer and the chrysalis undergoes diapause until the following spring (Opler and Krizek 1984). It is possible, but undocumented, that some chrysilids overwinter more than once before emerging.
J F M A M J J A S O N D
Reproducing Larvae present and active Pupae or prepupae present
The time of year you would expect to find West Virginia White reproducing (blue shading), larvae present and active (green shading) and pupae or prepupae present (orange shading) in New York.
Similar Species
  • Cabbage White (Pieris rapae)
    The cabbage butterfly has one or two black spots on the upperside of the forewing and has uniformly white undersides of the hindwing (with no color along the veins). Their flight is stronger than the flight of the West Virginia White and not as low to the ground (Opler and Malikul 1992). The caterpillar of the cabbage white has a thin line of small broken yellow spots along the side that is lacking in the West Virginia White (Opler and Krizek 1994, Wagner 2005).
  • Eastern Veined White (Pieris oleracea)
    The mustard white or eastern veined white has two generations and the spring individuals have underside wing veins more sharply outlined than West Virginia whites, while the summer flying mustard whites are completely white with no color along the wing veins (Opler and Malikul 1992). The mustard white and West Virginia white are very closely related and the caterpillars are very similar (Opler and Malikul 1992).