Lesson Summary
Students observe the J-shape that precedes the caterpillar’s transformation into a chrysalis. If possible, students witness the final molt that results in the chrysalis. The teacher assesses student progress in learning caterpillar anatomy and finds out how much students know about butterfly anatomy.
Teacher Background
The chrysalis appears to be lifeless, but it is not completely motionless. It may twitch from time to time. Inside the chrysalis many changes are taking place. The leaf-chewing jaw will become the butterfly’s proboscis. The simple eyes will be replaced by hundreds of lenses in a compound eye. Another name for this third stage is pupa.
The caterpillar does give clues that pupation is about to occur. After they grow in length to about 1 to 1 1/2 inches, the larvae stop eating and crawl to the lid of the cup. They spin a silk button on the lid. They lay head-down from the silk button in a characteristic J-shape. When these events occur, the chrysalis should form in a matter of hours.
Set-up/Management Tips
- Students whose caterpillars have not yet gone into a J-shape at the time of this lesson may observe a partner’s caterpillar or borrow one from the adoption center.
- Assemble the cage and display in the classroom, so it will be ready for chrysalises to be transferred as necessary. You may want to put paper towels or wax paper in the bottom of the cage for easier clean up at the conclusion of the unit.
- After chrysalises form and are dried and hardened, transfer them to the flight cage. This needs to be done within two to three days of them entering this stage. Handle them carefully by holding the tissue paper, not the chrysalis. The silk button attaching the chrysalis to the paper is strong enough to hold it. Attach it or tape it to the cage.
- Instead of taping the chrysalis to the cage, some teachers choose to put small plastic containers in the cage and tape the chrysalises inside the containers. This allows for easier clean up after the butterflies emerge.
Literacy Support
There are currently no VAST Mediagraphies listed for this unit.
Scientific Vocabulary
The following words are key vocabulary words that will be introduced in this lesson and reinforced throughout the unit:
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