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Tuesday, March 15, 2011

Spin on Pupation

So on the 12th the mourning cloak (Nymphalis antiopa) caterpillars marched out of their trees and onto my house.  They idled in their selected spots until yesterday when these prepupae assumed the J position.  They have by this time attached themselves to the house by means of a hooked appurtenance at the end of the abdomen that is anchored to a small pad of silk.
J one day before pupation

The first pupations occurred before a reasonable hour this morning; they were there hanging over the front door by the time I emerged for the day.  The shed larval skins, which look like mostly heads, were found on the porch below.

Over the next 10 hours the rest of the Js made the transition to pupae.

I got extremely lucky and noticed one next to the crawl space vent that was in the process of shedding the larval cuticle.  It gyrated convulsively as the skin gathered at the top (actually the pupa's bottom)

and then finally the crumpled old black spiny cuticle fell off.

The pupa moved around a bit for awhile; after about an hour it had compressed and hardened, the color changing and it looked very much like any other mourning cloak pupa I had seen.

1/2 hour after pupal molt

One hour after pupal molt

I noticed one of the Js twitching so I watched for awhile . . . a long while it seemed once the twitching stopped and the hanging continued.  So I entered into a what I thought was a shortish conversation with the old man (could have been an hour or so; he talks a lot) and when I checked back on that J it was already a pupa fairly well cured.  So the actual molt to pupa occurs quickly especially when you are not watching.

J a few minutes before pupation

In all there are seven pupae on the front of the house.  I'm sure there are many more in undisclosed locations.  The thesaurus gives synonyms like change, alteration, modification, evolution for metamorphosis.  The antonyms are stagnation, idleness, sameness.  The caterpillar changes dramatically in form through the process of metamorphosis; the process itself unfolds in predictable steps that don't change generation after generation, for disruption to or deviation from the process is likely to result in death for the individual butterfly.


Christine said...

I am fascinated! Please keep us posted!

daisugi said...

nice post.. i have some pictures of pupation too in my blog,