Black Swallowtail

In order to attract Black Swallowtails to your backyard you need to have their host plant in your garden. They love flowers such as milkweed, pentas, coneflowers, or zinnias.

Female butterflies lay eggs on specific host plants. Eggs are yellowish-white and laid singly on carrots, parsley, dill, fennel and Queen Anne's Lace.

There are 2 or 3 generations each summer....the second one emerging around mid-June and another in August or September.

They feed on plants that have toxic compounds in them and they store these toxins as they grow. When they are older and have stored enough of the toxins to be bad-tasting, they become more brightly colored, which warns potential predators of their bad taste.

There are five instars. After hatching, they are less than half an inch in length, barely visible at first glance. They are blackish-brown, with orange spikes and a central band of white, resembling bird droppings as they grow - a great defense against would-be predators. A horn-like projection called an osmetrium is another form of defense that appears from the head when disturbed, along with a foul odor emission.

By the fourth instar, spikes vanish and black and pale green stripes take their place. Fully grown, the caterpillar reaches about 2 inches in length and can make a dent in any garden with its voracious appetite.

Just before pupating, the caterpillar wanders from its food source to find a place to suspend its chrysalis. After clearing its intestine a final time, the caterpillar finds a suitable location and slowly attaches its head and last pair of legs with spun silk. After a final molt, the caterpillar transforms into either a brown or green chrysalis, blending with its surroundings.

The Swallowtail can spend as little as five days in the chrysalis, or as much as three or four months if it overwinters as a pupa. As emergence approaches, the chrysalis becomes more transparent, making the wings of the butterfly visible. When it emerges, the new butterfly will need to stay suspended upside down for a time as it pumps blood from its body into wrinkled wings not yet prepared for flight. This generally takes 1-2 hours,

They are mostly black with males having a band of yellow at the edge of its wings, while females bear a row of yellow spots instead. Both have a blue area between the bands on the hinds wings, though on females, this is more pronounced. Deep orange eye spots grace the tail end of both sexes, no doubt a hoax for predators. Native to North America, they are found in most states . The black swallowtail is the state butterfly of Oklahoma.