Sunday, December 13, 2009
Every day I find a new "favorite" photo in Gay's collection. As I continued working with more butterflies and caterpillars-- sorting and selecting the images I began to wonder "what exactly happens inside the chrysalis?". Ah, you are in for a treat, the answer is incredible.
My image of frivolous beings is gone. I am slack-jawed with what I learn about butterflies (Lepidoptera). In the previous post I was musing about what it might feel like to emerge from the chrysalis state and find yourself transformed into a butterfly (the imago). It is a vulnerable state. They have to dry out, pump up and harden their wings and establish circulation, make a proboscis (the tube they use like a straw to feed with), and not get eaten.
The process of transformation is simply amazing-- science fiction couldn't do better. A caterpillars and butterfly have all the same parts but these parts are formed for completely different life stages and purposes. As one biologist said "Caterpillars are all about eating, and butterflies are all about sex"
The caterpillar molts and then instead of creating new skin it makes a chrysalis. It then digests itself. It melts-- all of it, heart, nervous system, mouth....a partial death.
Most of the body breaks down into the "imaginal cells", which are undifferentiated -- like stem cells, they can become any type of cell. The chrysalis is a thimble-sized bag of fluid like a culture media. From this soup, in a matter of weeks or so, it varies with season and species, the imaginal cells put themselves back together into a new shape.
For a nice verbal and audio description of the process go to:
This process is hormonally regulated, of course....It is impossible for me to imagine what the caterpillar thinks is going to happen as it heads off to make the chrysalis. But, I suppose granting too much psychology to zoology should be done with caution.