Zebra Swallowtail Butterfly

Zebra swallowtail butterfly (Eurytides marcellus), as the name suggests, has black and white stripes on its wings, like a zebra. This butterfly belongs to the Papilionidae family, which has some of the largest butterflies as its members. The members of this family are called swallowtail butterflies, characterized by their large size and colorful wings. Swallowtail butterflies derived their name from the long tails on their hind wings, which resemble the long, pointed tail of a bird called swallow. Zebra swallowtail butterflies are commonly found in southern New England, eastern United States, north-east Mexico, south-east Canada and in the Gulf states. They are also the official state butterfly of Tennessee.

Physical Features
Zebra swallowtail butterflies have triangular wings with black and white stripes. The hind wings, which have sword-like tails also possess two blue markings at the base and a red spot near the body. The margins of the hind wings are scalloped. The wingspan of these butterflies range between 6 to 10 centimeters. There are two seasonal forms of zebra swallowtail butterflies - spring forms and summer forms (adult butterflies emerging from the pupa stage during spring or summer). It is said that spring forms are smaller when compared to the summer forms. The wings of the spring forms have more white color with black stripes. They have small black-colored tails with white tips. Summer forms have more black color in the wings and possess long tails with prominent white color.

Habitat and Food Habits
Zebra swallowtail butterflies are commonly found near pawpaw trees, the leaves of which are food for their larvae. These trees and butterflies are seen in open woodlands near swamps and rivers, grasslands, savannas and southern pine woods.

Adult zebra swallowtail butterflies lack jaws and they sip liquid nectar from flowers, using a straw-like organ called proboscis (coils up after use). Sometimes, they collect pollen from flowers with the help of 'proboscis' and digest it to absorb the proteins. The extra energy and nutrition from these proteins help them to mate and lay eggs for longer periods. Their mating season can extend up to six months. They feed on the nectar and pollen of flowers like blueberry, blackberry, lilac, redbud, verbena and common milkweed.

The caterpillars of this butterfly feed on eggshells, soon after hatching. After that, they proceed to the leaves of the pawpaw plant, which are small trees or shrubs with long, droopy leaves and produce an offensive, kerosene-like odor, when bruised. Some larvae are cannibalistic - they eat other larvae found on the same plant.

Life Cycle and Life Span
Male zebra swallowtail butterflies roam around in search of females for mating. After mating, the female butterflies lay spherical eggs (on each and not in cluster) on the leaves of the pawpaw trees and occasionally on trunks. The eggs are light green in color and turns brownish orange, after three days. The larvae are black in color on hatching, but as they grow stripes are developed. There are two types of stripe patterns in older larvae, which are hairless. The most common form have white and yellow horizontal stripes on green background. They have a band of three colors (yellow, black and bluish-white) between the thorax and abdomen. The second type, which is rarely seen, have white and orange stripes on black background. The distinctive feature of the swallowtail butterflies - the forked gland called osmeterium, located behind the head of the caterpillar, is seen in this species too. This structure, which is usually hidden, can be stuck out to release a bad smell to deter predators. These caterpillars live and pupate underneath the leaves of pawpaw trees.

The pupa is usually green or brown in color, and is small and compact as compared to that of the other swallowtails. They hang with their head upwards and binding to a stem or leaf with the tail. They also have a silk ring around their thorax. The life cycle of this butterfly is around one month. A period of one month is required for the eggs to develop into a full-fledged zebra swallowtail butterfly. Some pupa spend the entire winter in hibernation, before emerging as butterfly. After emerging, there is no growth stage for this butterfly and they will start reproducing. Such a butterfly, after emergence, may live up to six months in their natural habitat.

The next time you see a zebra swallowtail butterfly, you can recognize them by their unique stripes and the long tails.