Sunday, April 19, 2009

Metamorphosis: the Final Chapter

You may remember that we nurtured some Eastern Black Swallowtail caterpillars last fall (click on the "butterflies" label to see those posts). A few weeks after they formed chrysalises, two of the four butterflies emerged. The remaining two entered our indoor winter (the basement fridge) to wait for spring--most EBS's do overwinter in nature.

When warm weather arrived, we took the jar out of the fridge and set it in the kitchen. It usually takes 2-4 weeks for an EBS to emerge. The chrysalises start out bright green , although some turn brown (probably in response to attaching to rough vs. smooth wood). One of ours was still green, while the other had darkened to almost black, usually signifying a dead butterfly.

Well, on Easter Sunday morning, I noticed that the green chrysalis was now semi-transparent! I've seen pictures of Monarch chrysalises going from opaque to see-through, but have never noticed this change in our years of hosting EBS's.

The first two photos below show green chrysalises in the fall. Third is a picture of Easter's chrysalis. Can you see the spots inside?
What an exciting image for Easter! That body, encased as though in a tomb, transformed and reentering the world.

Every now and then the chrysalis would move, jerking from side to side. Len managed to catch some of the action on camera. The frame wiggles a bit (he was holding the stick in one hand and the camera in the other), but it's still very cool:

We didn't want to miss the butterfly's entrance and so took the jar in the car on our way to the bluebells. As we drove home it emerged, although even Marianna (who had the jar on her lap) missed the actual moment!

The butterfly's wings were wrinkled. It took a while to pump them up with fluid and get ready to fly; at one point it fell to the bottom of the jar. I "rescued" it using a trick learned from a book: I offered it the bristles of a soft paintbrush as a way back to the branch.

Here's a picture of the butterfly readying its wings. Notice the spots on its body and then look again (below) at the transparent chrysalis. Wow! Updated to add: Yes, the blackened chrysalis held a dead butterfly (we opened it). It had darkened in the fall (at about the same time the other two completed their cycles), so we weren't surprised to see a dried out body this week.


Anne said...

Loved the video!! Thanks for the great science lesson. Just wish we had the bluebells to visit.....

Happy Easter season!

Mom/Mimi said...

WOW! Truly awesome. Thanks for educating me. What a great project you have undertaken.
BTY, was the other butterfly indeed dead?
Love to you all,