Black Swallowtail Butterflies

This "event" actually has four pages, which depicts the birth of a butterfly from start to finish. We are honored to have been able to observe this miracle in action.

Be sure to click the links at the bottom of each page. The second page shows the chrysalis (cocoon) emerging from the caterpillar. The third page shows the butterfly emerging from the chrysalis and has pictures of a male Black Swallowtail. The fourth page shows pictures of a female Black Swallowtail.

About butterflies:

  • The egg - depending on the species, the adult female butterfly may lay from dozens to hundreds of tiny eggs. She may drop them near plants that will be food for the caterpillar, or she may lay them on the undersides of leaves that the caterpillars will eat. Some eggs hatch in a few days (like the eggs of the Swallowtail), but other types of butterflies lay eggs in the fall. These eggs stay on the plants until the spring.
  • The caterpillar - it begins to eat as soon as it hatches. Often it eats its own eggshell, then begins eating part of the plants surrounding it. They eat so much that they may increase their birth weight by 3,000 times before they are full-grown. As they grow they shed their skins, sometimes as many as five times.
  • The chrysalis (KRIS-e-lis) - when the caterpillar has eaten and stored enough food to keep it alive during its next life stage, it begins to change. It usually finds a high, safe place and puts out a sticky liquid. It hangs from this sticky spot as it forms the next stage, the chrysalis, which is kind of a shell around itself - which it creates from parts of its own body. Inside the chrysalis the caterpillar's body is being completely remade and rearranged. It is making new eyes, new legs, and wings. The digestive tract is about the only thing that stays the same. Depending on the species, it may be in this form for days or months. 
  • The butterfly - when it is ready, the chrysalis splits open and a butterfly comes out. It will hang there until its wings dry and harden. It then spreads its wings and flies away. Some butterflies live for only one to two weeks. Others may live for more than a year.

(Click on all of the small thumbnail pictures that follow to enlarge them.)

In early June I saw a black swallowtail butterfly on the dill. The next day we found lots of tiny caterpillars on it. We brought in three (we thought) but within a few days four more hatched out. (Of a total of about 25 on the dill outside, none are left. Wasps got them.)

At first I had our caterpillars in a large glass bowl. I put a couple of small containers of water in the bottom and cut paper plates to cover the smaller containers of water. I punched holes in the paper plates so I could stick the stalks of dill sprigs down in the water to keep them fresh. (In the top right picture you see two of our "big guys" and one of the little ones.)

All the caterpillars do is eat, poop, and rest, and they grow visibly larger each day. The bowl was going to become too crowded when all those caterpillars grew up, plus we needed a top for them to "hang" on when the time came. So Harry made a "bug box" of hardware cloth (a small screen wire).  We are excited "parents!"

One time I saw one of the four smaller caterpillars lying on his side and I saw a little “ooze” beside him. I thought he was dying. I kept watching, and over a period of about half an hour I discovered he was just emerging from the old skin. After that, he was perky again and ate ravenously. 

An interesting thing that I haven't seen mentioned anywhere else: when the caterpillar feels threatened, little orange extensions that look like feelers emerge from his head and they emit an unpleasant odor.

Monday 6/17/02  – evening – one of the three larger caterpillars did a massive “poop,”  got very restless, and traveled all over the wire of the bug box. Finally he settled down, hanging from the wire on the top. Then he spun his girdle, which is a tiny thread that anchors him to the surface from just below his head – from the area of what I would call his “shoulders.” The second of the larger caterpillars soon followed the same procedure. They still had all pairs of feet attached to the wire (see the picture beneath the bug box), but gradually over a period of a couple of hours they relaxed and were attached only by the back pair of feet and the girdle. A few times they did some fairly violent twitching and we thought maybe the chrysalis would pop out then. But then they settled down and were perfectly still. They had shrunk to about 1/2 of their original size.

The last picture:  Now he has relaxed and let go with all but his back feet. He seems to be in a state of suspended animation.


All images are copyright of Dottie Atwater
Please request permission to use these images
for anything other than personal use.

Please go to the NEXT PAGE to see the chrysalis emerge from the caterpillar.
(That's the cocoon that the butterfly grows in.)

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