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:

http://www.learner.org/jnorth/tm/monarch/ChrysalisDevelopmentLPB.html

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.

2 comments:

Lynne said...

On an undersea expedition once, I heard about a species of fish that lives in harem-like community, one male fish and many females. When the male fish dies, the lead female swims off, to return to the community after a period - as a male! What do these transformations tell us about creation, imagination, sense of humor, possibility? You're right, Sharon, it's better than science fiction, and it's non-fiction. It's our world.

Sharon said...

Oh, nice image Lynne. I wonder how the remaining group of females decide which among them will be the one selected to be the male. Do you think it would be an honor to be selected or the "short straw"? And, then, what does the selected female do when she goes off? What rich possibility for story.

In many species the environmental temperature defines whether most of the hatchlings or newborns will be male or female. In some the development of sexual characteristics develop after birth in response to the environment and "social" need.

Sounds like many species are much less "attached to sex/gender whereas others are driven almost entirely by it. I'd love to see a whole set of vignettes with pictures about different ways that sexuality can be expressed in those that have flexible approaches/means. It makes me think that we have looked at sex as as Yes/No or Male/Female switch and the more we learn the less that is sensible.
Thanks