Papilio glaucus

Papilio glaucus, the eastern tiger swallowtail, is a species of swallowtail butterfly native to eastern North America. It is one of the most familiar butterflies in the eastern United States, where it is common in many different habitats. It flies from spring to fall, during which it produces two to three broods. Adults feed on the nectar of many species of flowers, mostly from those of the families Apocynaceae, Asteraceae, and Fabaceae. P. glaucus has a wingspan measuring 7.9 to 14 cm (3.1 to 5.5 in). The male is yellow with four black 'tiger stripes' on each forewing. Females may be either yellow or black, making them dimorphic. The yellow morph is similar to the male, but with a conspicuous band of blue spots along the hindwing, while the dark morph is almost completely black. The green eggs are laid singly on plants of the families Magnoliaceae and Rosaceae. Young caterpillars are brown and white; older ones are green with two black, yellow, and blue eyespots on the thorax. The caterpillar will turn brown prior to pupating. It will reach a length of 5.5 centimetres (2.2 in). The chrysalis varies from a whitish color to dark brown. Hibernation occurs in this stage in locations with cold winter months. The wingspan ranges from 7.9 to 14 cm (3.1 to 5.5 in) with females being the larger sex. Southern individuals are larger than northern ones. Males are yellow with four black 'tiger stripes' on each forewing. The outer edge of the forewing is black with a row of yellow spots. The veins are marked with black. The postmedian area of the hindwing is black with yellow spots along the margin. The inner margin of the hindwing has small red and blue spots. The ventral forewing margin has a yellow bar that is broken into spots. This broken bar is present in both sexes, and is used to distinguish P. glaucus from its close relatives. Females are dimorphic. The yellow morph differs from the male in having a blue postmedian area on the dorsal hindwing. In the dark morph, the areas that are normally yellow are replaced with dark gray or black. The bluish postmedian area on the ventral hindwing has one row of orange spots. A shadow of the 'tiger stripes' can be seen on the underside of some dark females. P. glaucus is one of a few species of papilionids known to produce gynandromorphs. Most bilateral gynandromorphs are hybrids of P. glaucus and P. canadensis that are found along hybrid zones. Color mosaics are found in the central part of the species range. The first known drawing of a North America butterfly was of an eastern tiger swallowtail. It was drawn by John White in 1587, during Sir Walter Raleigh's third expedition to Virginia. White named his drawing 'Mamankanois' which is believed to be a Native American word for 'butterfly'. This species was later described by Linnaeus in his 10th edition of Systema Naturae in 1758. Some taxonomists place P. glaucus, along with the other tiger swallowtails, in the genus Pterourus. The eastern tiger swallowtail was formerly considered a single species with a vast range into northern Canada and the eastern United States. In 1991, the subspecies Papilio glaucus canadensis was elevated to species level, thus reducing the range of P. glaucus to south of Canada. In 2002, another closely related species, P. appalachiensis, was described by H. Pavulaan and D. M. Wright from the southern Appalachian Mountains. These two species can be separated from P. glaucus by size; P. canadensis is smaller and P. appalachiensis is larger. These two also have a solid yellow bar along the margin of the ventral forewing. P. canadensis females are not dimorphic, and P. appalachiensis females are rarely black. Similar species for the dark P. glaucus female include the pipevine swallowtail (Battus philenor), the spicebush swallowtail (Papilio troilus), and the female black swallowtail (Papilio polyxenes). B. philenor differs from the dark morph P. glaucus by the row of light-colored spots on each wing margin. P. troilus is more greenish, and has two rows of orange spots on the ventral hindwing. P. polyxenes is smaller, and the ventral hindwing has two rows of yellow-orange spots.