North American Range
The white band is a recessive trait. It could potentially occur in any population. Both forms interbreed where their ranges overlap producing intergrades with partial bands. The Red-spotted Purple has a more southern range, and is a Batesian mimic of the Pipevine Swallowtail. Males perch 3 feet or more above the ground on trees and tall bushes and rarely patrol for females. Eggs are laid singly on tips of hostplant leaves; caterpillars eat leaves. Third instar larvae overwinter.
Upperside is blue to blue-green with much iridescence on the outer part of the hindwing. Underside is dark brown. Forewing has 2 red-orange bars near the base of the leading edge; hindwing has 3 red-orange spots near the base and a submarginal row of red-orange spots. The two forms hybridize where their ranges overlap, creating various intermediate forms which may be found in or near the overlap zone.
Flight periods of both forms overlap. Both appear to have a smaller second generation in August. White Admiral can be incredibly abundant in late June and early July. Extreme dates: Red-spotted Purple – 17 May 2003 in Weybridge (D. Peterson) and 25 August 2002 in Chester (M. Reiter). White Admiral – 24 May 2004 in Pownal (K. Hemeon) and 1 October 2002 in South Burlington.
Distribution and Habitat
Red-spotted Purples were found primarily in southern half of Vermont. Hostplants are the leaves of many species of deciduous trees and shrubs. Adults feed from sap flows, rotting fruit, carrion, dung, and occasionally nectar from small white flowers. White Admirals also sip aphid honeydew.