by Patricia Dung, Specialist, LAUSD and the Los Angeles Educational Partnership

Conduct an experiment with your students using the Painted Lady butterfly chrysalides. You will need this data sheet.

Materials:

• 6 larvae each in its own food container. Note: Although butterfly larvae may be gathered, it is probably more convenient to order them from a biological supply company such as Insect Lore; Carolina Biological; or Bioquip.

• Heat or light source

Have your students use either of the two following variables in your experiment with the chrysalis stage of the butterflies: Dark vs. Light or Heat vs. Cold. As soon as each larva enter s the chrysalis stage, place the container in the conditions described below. Number the lid of the food container from 1-6.

Procedure for Dark vs. Light:

• Keep 2 of the chrysalides under constant light, but not so close that they will be excessively heated.
• Keep 2 others in a constantly dark environment, such as inside a shoebox or cupboard.
• Keep the CONTROL pair on a counter or table in the room, exposed to the natural light of day and night.

Procedure for Cold vs. Heat:

• Keep 2 of the chrysalides in the refrigerator (should be about 40 degrees)
• Keep 2 others in a heated area, such as a brooder box for hatching eggs, under your water heater, under a heat lamp, or some other constantly warm area.
• Keep the CONTROL pair at room temperature.

Have your students formulate a hypothesis about what they think will occur as a result of the experiment. Have students work in groups to observe one of the chrysalides daily until the adult butterfly emerges. Each group records its data daily on a copy of the chart below.

Discuss with your class:

1. Did the six chrysalides vary in the time they spent in the chrysalis stage?

2. If so, from which chrysalis did the adult emerge first? In what condition was the chrysalis placed?

3. From which chrysalis did the adult emerge last? In what condition was the chrysalis placed?

4. Do you think Light vs. Dark or Cold vs. Heat affected the time the butterfly spent in the chrysalis stage? What is your evidence?

5. Which condition was the most normal of the three? This condition is called the control. It is used to compare the other conditions.

6. Was there a condition or variable that you found it hard to keep the same all the time? What was it? Why was it hard to keep this the same? Do you think this affected the results of your experiment? Why or why not?

7. If you were to do the experiment again, what would you do differently?