WHY DO CHRYSALIS HANG ON LEAVES?
I found this out the hard way after drastic pruning of my curry plant to save it. Flowers started to blossom on my curry plant, lots of butterflies visited it. Soon after, caterpillars started to appear and chomped on the leaves.
I decided to keep a few for my 2.5 year old daughter Faith. Her first pet. They were easy to keep, she would feed them with leaves, I would remove their droppings periodically and they would be as happy as clams. These caterpillars have voracious appetites. Leaves seem to just melt away when their heads touch them.
If you were to disturb the caterpillar it may extend a thin red forked extension and exude a pungent smell. Seen from afar, the markings of the caterpillar and the thin red forked extension makes it look like a green tree snake.
The caterpillars grew to a size of about 1.5" & about 0.3" before they slowed down in their eating. They would then climb to the top of the box, stuck themselves there and become chrysalis.
When metamorphosis completed in about 10 days time, the chrysalis became more and more transparent until you can almost see the insect inside. The species that I had was a Black Swallowtail butterfly.
What struck me as odd was that during caterpillar stage the head of the caterpillar (the chomping end) became the tail of the butterfly.
So why do the caterpillars instinctively know to climb up and hang.
THE ANSWER:
Here's where I discovered the hard way through my ignorance. If it were hanging, it won't encounter the following problems.
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Weak covering During the early stages of metamorphosis, the outer covering was not stiff enough to support the weight of the chrysalis. When the unfortunate chrysalis was lying sideways, the section that it was resting on, flattened. You can see two horn cone-like structures on the right side of the chrysalis in the picture. Beneath it were the eyes of the insect. This was apparent when the chrysalis became transparent just before the butterfly emerged. They remind me of the crumple zones in cars to absorb head on collisions. |
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Insect
attack I placed four chrysalis in a clean box. A few days later, there were some tiny insects crawling in the box. Soon after a yellow maggot emerged from a chrysalis. That maggot ran around the box very quickly and after a few hours, turned into a black pill seen on the extreme right. Few days later, another yellow maggot appeared from another chrysalis. Curious to see what was inside the black pill, I cut one up expecting to see an empty shell. Instead it was filled with some kind of yellow sticky liquid. I think I cut whatever creature into two! I put the remnants into the pot of the curry plant. Despite waiting for weeks to see what would happen to the remaining black pill, nothing changed. I put it back into the pot of the curry plant. Ants came so I think it must have contained some organic matter. The brown chrysalis seen 2nd from the left in the picture didn't make it. Something went wrong during metamorphosis. It remained in that state for weeks and began to smell. I fed it to my curry plant. |
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Sticky liquids and heavy body When the butterfly emerged, lots of sticky liquids were expelled at the same time. These caused the soft wings of the butterfly to stick to the bottom of the container. The compacted wings needed unobstructed space to unfurl. The force to unfurl the wings comes from liquids being pumped through tiny tubes in the wings. It was just enough to expand an unobstructed wing and the weight of the insect resting on it was too much for the hydraulics to work properly. By the time I noticed it, the wings had hardened in its deformed shape. It was so pitiful seeing the butterfly trying to flap its crumpled wings. |
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SUCCESS!
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 For the subsequent chrysalis, I hung them on a thread in the centre of a large container. This gave the wings plenty of room to expand. Just in case the butterfly were to fall down from its perch (which this one did), I lined the bottom of the container with tissue paper to absorb any liquids. That way should the butterfly fall, their wings won't stick to the bottom of the container and it is easy to provide something for the butterfly to climb up.
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This is the empty chrysalis on the right with
the dried out caterpillar head is still attached to it. The two
"horns" at the bottom was where the butterfly head was. The 7" diameter x 12" tall plastic container that I used contained yummy popcorn. |
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Some photo highlights
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2. Chrysalis on the 10th day. The covering was nearly transparent and the insect could be seen inside, facing down.
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3. The butterfly crawling out of the chrysalis. From the first break out to climbing out, it took less than 10 seconds. Lots of liquid were expelled as well. Notice the swollen abdomen which contains liquid to pump out the wings. This was the most difficult stage to observe because it happened so quickly. |
4. The wings are limp and soft at this stage. From time to time, excess liquid was passed out of its abdomen.
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5. The fully expanded wings. The abdomen was not as swollen as in picture 3. |
6. I hung the butterfly outside on my curry plant for better air circulation to dry out the wings. When the wings were stiff enough, the butterfly opened it flat to increase the surface area and help it dry faster. |
7. After a few hours the butterfly flew off when I approached it. It was the most beautiful sight to see it flapping its wings. This is what was left of the fond memories. |
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AFTER THOUGHTS
I missed 6 emerges before I finally got to witness the butterfly breaking through its chrysalis. Each time it happened whilst I was sleeping or doing something else so I asked God for the opportunity to witness the butterfly crawling out of the chrysalis.
I thought it was mighty generous of God to grant such a frivolous request of mine. Here is a God who's so busy with so many other things and yet cares enough to satisfy my curiosity to witness his wonderful transformational work, metamorphosis.
What's the hurry to get out of the chrysalis?
I asked this question as I kept missing the part where the butterfly crawls out of the chrysalis.
When the butterfly is ready to come out of the chyrsalis, it is filled with some liquid that softens the covering. It then uses it legs/head and pushes against the chrysalis. This causes the covering to split open. From then onwards, the clock starts ticking. The liquid when exposed to air dries up, hardens and becomes like glue.
If the butterfly cannot clear the chrysalis fast enough, it will get trap inside. Once trap, more appendages would get stuck inside.
This happened to the chrysalis which was deformed (see the picture in the section "Weak covering"). The deformed section was flat and the wing got stuck on it. I saw the butterfly pushed and rested intermittently. After 8 hours I realised something was wrong and tried to help it out by carefully peeling off the chrysalis covering. As I did it, I found that the covering was stuck to the body and I applied a little water to soften the "glue". It was a very delicate operation as its fragile legs, antenna, probosis were all stuck to the chrysalis covering. When I finally got the covering off, I was not able to do a 100% job and found one leg had broken off and was stuck to the covering. It struggled to get on its feet to unfurl its wings. Despite waiting for an hour, its wings couldn't open as they had already hardened whilst it was trap inside the chrysalis. The butterfly helplessly tried to flap its unfurled wings. It was a pitiful sight.
Instinctively, the insect knows that it had to get out of the chrysalis as fast as it could or face certain death.
leewm at Apr 04 starhub dot net dot sg
