Caterpillars have a chemical called juvenile hormone in their bodies that is made by their brain. Whenever a caterpillar sheds its skin and the juvenile hormone level is high it goes to the next caterpillar stage. When the juvenile hormone level is low the caterpillar wanders to find a site to make a chrysalis (or a cocoon if its a moth), then it becomes a chrysalis and not another caterpillar stage.
How do caterpillars "know" when it is time to turn into a chrysalis?
Did you find the answer to your question?
If not, browse all frequently asked questions.
If your question isn't answered on this site, you can submit a new question to our Lepidopteran expert Dr. Opler, who replies via e-mail at: pauloper(at)comcast.net. Please note: because Dr. Opler has recently "retired", he is frequently in the field working on butterfly research around the world. There will be a 1-2 week minimum delay in answering your questions.
