The Eastern Black
Swallowtail is a common swallowtail butterfly, often
confused with the Pipevine Swallowtail or female Tiger
Swallowtail.
Both male and female
Eastern Black Swallowtails are bluish-black with yellow
spots on the wings. They also have two orange eyespots with
black dots in the middle.
The male has a yellow
band on the hindwings with a blue cloud under it. The female
has a row of yellow dots above a blue band. It's easiest to
remember that males have more yellow, and females have more
blue.
Eastern Black
Swallowtails take flight in late March and continue until
September. After mating, the female lays small yellow eggs
on a host
plant. A host plant is the plant that the caterpillars eat.
The caterpillars, when they hatch, are brownish-purple and
white. They are small and look like bird droppings. This
probably helps camouflage
them. As the caterpillars get older, they look like the
picture above. They are two inches long, leaf-green with
white, black bands, and yellow spots.
The main host plant for
this butterfly in the wild is Queen Anne's Lace, but they
also eat garden plants in the carrot family, including
carrots, parsley, dill, and fennel.
Once a caterpillar is old
enough, it will form a chrysalis
like the picture to the left, usually brown or
green.
This animal will overwinter
in the chrysalis, meaning it won't hatch into an adult until Spring.
The adult will drink nectar
from many different flowers, including milkweeds, thistles, Red
Clover, and Purple Coneflower.
The Eastern Black Swallowtails
will search open spaces, such as meadows,
gardens, banks of streams and ponds, marshes,
and roadsides in search of nectar and mates. They usually flutter
around, but when they are disturbed they fly straight.
This butterfly is a
mimic,
meaning its pattern copies another animal. Its cousin, the Pipevine
Swallowtail is poisonous
to many predators.
By copying the Pipevine Swallowtail, the Eastern Black Swallowtail
gains protection from predators, even though it is not poisonous.
This animal is most often eaten as a caterpillar.
* Click the link above to see a
time-lapse animation of an Eastern Black Swallowtail caterpillar
changing into a chrysalis. A time-lapse is when a video is "sped up."
The animation you will see actually took 27 minutes to happen, but
the photographer "fast forwards" so you can see what happens in only
a few seconds.
Like all butterflies, the Eastern
Black Swallowtail is a good pollinator.
As it visits plants, looking for nectar, it spreads pollen
from flower to flower so the plants can grow. This is helpful to
people if the plants are desirable, but pesky if the plants are
considered weeds.
Some people consider the
caterpillars of this butterfly to be a pest, since they eat parsley,
carrots, and other garden plants.
Many people enjoy
butterfly-watching and collecting, and the Eastern Black Swallowtail
is considered by most to be a handsome specimen.
