All photos, background
and buttons are copyrighted by Sue.
I never realized I had Black Swallowtail butterflies in my garden until I discovered the caterpillars on my dill plants. Finally, I saw the butterfly, flying low. It stopped at my dill and deposited a few eggs. Since then I describe this butterfly as a dark shadow that sneaks into my garden. I have planted more dill, some parsley and fennel; all are host plants for the Black Swallowtail. In my garden, dill is their preferred choice. The butterfly enjoys my Butterfly Bush, zinnias and some other flowers. The black wings, dotted with iridescent blue and yellow patches, catch my eye.
Black Swallowtail enjoying nectar from a Butterfly Bush.
The caterpillars are easy to raise. They can be left to fend for themselves. However, the wasps patrol for the caterpillars and eggs. I find the wasps more active when the dill is flowering. Last year I pinched off the flower heads (until I wanted some seed). This encouraged the plant to grow taller and not as many wasps were checking for caterpillars.
Two different instars of the caterpillar. The first looks like bird poop.Both instars hide the caterpillar pretty well on the dill plants.
One of the last instars. As you can see thecaterpillar changes yet into another skin.
The eggs are yellow in color and the size of a pin head. You may look through your dill and not notice anything, but look more carefully and slower. You may find the eggs appear before your eyes. (Photo is enlarged.)
I often grow a pot of three plants of parsley. Then I transfer six to eight caterpillars to these plants. I place an upside-down tomato cage over the pot. Then cover with screening or tulle (bridal veil). Another method is to build a box with screened sides to move the pots into or use PVC pipes to form a box and cover with bridal veil or screening. This protects the caterpillars from their predators. When the caterpillars are large, I place sticks in their enclosure and usually they form their chrysalis on the sticks. The chrysalises' color varies from white to brown to green. This depends upon their surroundings, to blend in or for some other reason. No one seems to know for sure the reason for the different colors.
The first picture is of two caterpillars ready to go into chrysalis form. The second pictureyou will notice a small gap between the stick and the head. First the caterpillar spins a lineof silk to hold the upper body, before it continues on with spinning the chrysalis.
This chrysalis picture was taken in the wild. It was under
a concrete ledge on my house.
It is tricky to predict when this butterfly emerges from its chrysalis for the Black Swallowtail. Another fact is that this butterfly may over-winter. I had chrysalises in late July that did not emerge until the next summer. When over-wintering hand-raised caterpillars, I place the chrysalis in a Tupperware container and wrap them in paper towels. I place a cover on the container and store them in the refrigerator. Then the following year when I am ready, I bring the chrysalises out. The one time I tried this method, it took two weeks for the butterfly to emerge. If one places the chrysalises in a garage for the winter, you may run the risk of a early warming spell that confuses the butterfly into emerging early and the weather was not ready for them. This results in a short life for the butterfly as the weather will not be warm enough. This year I noticed that some of my caterpillars were darker in color as the season progressed. This difference in color is called melanic and is considered normal.
All in all, I find it interesting to sit back and observe, learn and take photos.
A beautiful newly emerged Black Swallowtail butterfly.