Wednesday, October 24, 2007


The caterpillars have made lots of changes these past few days. As of right now we have 3 chrysalids (plural of chrysalis), 3 J's, 1 large caterpillar getting ready to be a J, 1 large one still eating, and 4 babies! Whew!

Two days ago, our first 2 caterpillars climbed to the top of their cage to start their transformation. The first thing we noticed, was that they got shorter and fatter. They'd been about 1.75 inches, and they "shortened up" to 1 inch! Then, or maybe while this was happening, they each spun a silk pad which they would later hang from with their last pair of prolegs. (Caterpillars have 6 "true" legs which they'll keep as butterflies and 10 prolegs which will disappear during metamorphosis.)

By yesterday morning, both of these caterpillars were hanging in the J-shape as seen on the left. (The one on the left isn't one of the original 2.) We missed the molting of the first caterpillar, but we actually got to watch the second one molt! I got a poor video of it, but it is still neat. I took this through the side of the plastic cage. We have 3 more who should molt this evening, and I'm hoping to watch and video it!

Too bad videos on blogs are so small - I can watch this full screen. Anyway, they one wiggling around & around & around is the one molting. He's working his exoskeleton off (It's dark near the top of him.) He did this for about 20 minutes, I'd guess. Usually, the skin will finall drop off. This one didn't - it's still sitting on top of his chrysalis, perhaps because we interrupted him.

Now, we will wait about 9 - 14 days to watch the butterflies emerge! The chrysalids should darken as they become transparent about a day before it emerges, so hopefull we'll get to see that, too!
I'm finding the following information from Wikipedia very helpful:
The Monarch goes through four radically different stages:

1. The eggs are laid by the females during spring and summer breeding months.
2. The eggs hatch, revealing worm-like larva, the
caterpillars. The caterpillars consume their egg cases, then feed on milkweed, and sequester substances called cardenolides, a type of cardiac glycosides. During the caterpillar stage, Monarchs store energy in the form of fat and nutrients to carry them through the non-feeding pupa stage.
3. In the pupa or chrysalis stage, the caterpillar spins a silk pad on a twig, leaf, etc. and hangs from this pad by its last pair of prolegs. It hangs upside down in the shape of a 'J', and then molts, leaving itself encased in an articulated green exoskeleton. At this point, hormonal changes occur, leading to the development of a butterfly. The chrysalis darkens (actually becomes transparent) a day before it emerges, and its orange and black wings can be seen.
4. The mature butterfly emerges after about two pupal weeks and hangs from the split chrysalis for several hours until its wings are dry (often in the morning). Meanwhile fluids are pumped into the crinkled wings until they become full and stiff. Some of this orangy fluid drips from the wings. Finally (usually in the afternoon) the monarch spreads its wings, quivers them to be sure they are stiff, and then flies in a circle and away, to feed on a variety of flowers, including milkweed flowers, red clover, and goldenrod.


Robin said...

What a great post, Dana! I can't wait to see the culmination of the whole process. It was weird, but cool to watch the little guy wiggling around. I've never seen anything like that.

live4evermom said...

So cool!

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