Saturday, June 11, 2011
Shedding and Pupating
When a caterpillar is ready to shed, it will often wander a short distance from the milkweed plant, and just sit there for a day. You may think it's dead, but it's not. Be careful not to disturb it -- even though it's not moving, it's alive!
After the caterpillar has shed its skin four times (when it's called a "fifth instar"), it keeps growing until it's ready to pupate. It will probably crawl off somewhere, and then sit still, just like the other times when it sheds its skin.
As it hangs, it will gradually bunch up, and get shorter and fatter, until it sheds its skin one last time -- but now, instead of coming out from its skin as a larger caterpillar, it comes out as a pupa!
The pupa is this smooth, green capsule. It has a few shiny dots on it, and if you look carefully, you can see the tracings of what look like a butterfly wing inside. We'll watch carefully over the next ten or so days, and see what happens with this pupa!