Tuesday, July 29, 2008

Monarch Pupa - Day 2

Our monarch pupa is fully formed and will remain in this state for 10-14 days before the butterfly emerges. The outer surface has hardened and is bright green with gold spots. It is beautiful! I read that at this point, the pupa can be removed and moved to a different location if needed but we will try to keep our milkweed alive long enough so that we can keep the pupa in the same spot.
Interesting facts about the pupa stage:
1. During the pupal stage, a butterfly will make a chyrsalis and a moth will spin a cocoon.
2. What does it look like inside the pupa? Initially, there is a bright green liquid called hemolymph This is the blood of the organism. As the adult develops, the hemolymph no longer flows throughout the pupa. The shape of the wings can be seen when the pupa is still green and when the adult is ready to emerge, the black and orange wings can be seen through the pupa. After the adult emerges, the empty pupa is brittle and opaque.
3. The function of the gold spots isn't clear but is most likely related to distribution or formation of wing coloration. It also might have to do with defense - warning coloration or camouflage. A group of researchers in Germany did a careful study of the properties of these spots. They are not metallic (so they aren't really gold), but the cells reflect light like metals do, giving them the appearance of being metallic.
4. The hard outside layer of the chrysalis is called the cuticle. Apparently there is a way to determine the sex of the pupa from a line that is present on the female cuticle and absent on the male. But it can only be seen with a magnifying glass and I couldn't find any pictures.
5. It is unusual for the caterpillar to pupate on the milkweed plant. Apparently they usually find a different location.
Information comes from www.monarchlab.org
Now we wait and watch!

1 comment:

Anna said...

I could probably come down next week...this is totally mesmerizing.