Eastern Black Swallowtail

By Julie Jensen

Black Swallowtail
Black Swallowtail


The Black Swallowtail likes open habitats. It is found in fields, meadows, deserts, marshes, near lakes and streams, farms, lawns, near cities, near roads, and gardens. It is rarely found in forests or woodlands.
Humans have greatly helped the Black Swallowtail. They brought non-native carrot species from Europe to North America. The Black Swallowtail uses these plants as host plants. Before humans cut down forests, Black Swallowtails were rare. They were only found in small prairies, wetlands, and openings in forests.

The Black Swallowtail flies very fast. Its flight is much quicker than other swallowtails. The Black Swallowtail flies closer to the ground than other swallowtails do. In cold weather, they will hold their abdomens above their wings, this keeps them warm. Usually, Black Swallowtails live about 10 to 12 days. Some however, can live up to 35 to 40 days. Some of the food sources for the Black Swallowtail are milkweed, butterfly weed, thistle, purple coneflower, alfalfa, lilac, ironweed and zinnia. Males will also come to damp soil and mud to feed on minerals and moisture. This is called puddling.

Life cycle
The Black Swallowtail goes through complete metamorphosis. The territory is usually on the top of a hill. The male will sit on high branches or other vegetation on the hill. He will defend his territory from other male Black Swallowtails. If other males come too close, he will chase them away. The female will fly to the top of the hill to look for a mate. A successful courtship lasts for about 40 seconds. Females that do not want to mate will try to escape from males by flying high in the air and then quickly flying downward.

Female Black Swallowtails fly close to the ground to look for host plants. Females lay one egg per host plant. The eggs are laid on the leaves and flowers. The egg is yellow. It later forms a red ring around the center, and then a red top. It will turn dark gray just before hatching. It takes about 10 days to hatch. In a lab test, females laid a total of about 200 to 430 eggs. They laid about 35 to 50 each day.


The caterpillar will eat the leaves and flowers of the host plant. The young caterpillar is black and has a white spot in the middle of its body. This spot is called a saddle. It mimics a bird dropping. The older caterpillar is green and has black bands with orange spots in each of the bands. The caterpillar has a special organ called an osmeterium. It is an orange, bad-smelling organ. It is shaped like a snake's tongue. It is kept behind the inside of the hea The caterpillar releases it to scare predators away. The caterpillar will reach a length of 2 in.


The chrysalis hangs upright. There is a silk thread around the upper part of the chrysalis. This thread is called a girdle. The chrysalis is either brown or green. The Black Swallowtail will hibernate as a chrysalis.
Adult butterfly The Black Swallowtail has a wingspan of 2.7 to 4 in. The upper side of the male's wings is black. There are two rows of yellow spots along the edges of both wings. There is a small area of blue on the bottom wing between the two rows of yellow spots. On the bottom edge of the bottom wing, there is a red spot with a small black dot in the center. The upper side of the female's wings is black. There are two rows of light yellow spots along the edges of both wings. These spots are smaller than the male's. There is a large area of blue on the bottom wing between these two rows. The female also has the same red and black spot on the bottom wing as the male. The underside of
the wings is the same in both sexes with the top wing being black with two rows of yellow-orange spots. The bottom wing has two rows of orange spots with a blue area between them.

Report by Julie Jansen, sources: wiki.kidzsearch