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The Effect of Temperature on a Developing Chrysalis

Humboldt Jr. High School
St. Paul, MN

Abstract

In this experiment we tested to see if putting chrysalises in different temperatures affects the size of the adult butterfly. We put chrysalises in the refrigerator, the greenhouse and our classroom until they emerged into adults. We found that the chrysalises that developed in the greenhouse were the largest butterflies and the ones that developed in the refrigerator never emerged. The experiment would have been more accurate if the same person took all the measurements and if we started with eggs instead of chrysalises. We learned that chrysalises don't emerge in very cool temperatures and we learned that the warmer the temperature, the faster the chrysalis develops.

Problem

How does the temperature affect the size of the adult monarch butterfly (during chrysalis development)?

Hypothesis

I think the larvae will get bigger in the heat.

Justification

I think they will get bigger in the heat because the heat will speed them up and make them grow larger.

Materials

  1. cups
  2. 3 boxes
  3. string
  4. rulers
  5. sticks
  6. 3 cloth covers
  7. thermometer
  8. fridge
  9. greenhouse/heat lamps
  10. chrysalises
  11. pencils
  12. balance
  13. data recording sheet

Method

  1. Gather 18 chrysalises
  2. Measure chrysalises with a string. Wrap string around chrysalis and mark it, then measure the mark on the string with a ruler.
  3. Record age of the chrysalis and date.
  4. Make cages and gather a popsicle stick, string, and paper cup.
  5. Make containers
  6. Tie chrysalis to the string, then attach the string to the popsicle stick and stick to the cup.
  7. Place chrysalises in 3 different boxes covered with black plastic.
  8. Store these boxes at 3 different temperatures: room, fridge, and greenhouse.

Daily Upkeep

Make observations and take temperatures for two weeks. Record this in the data table.

Once They Emerge

Measure wing span.

Results

The temperature in the greenhouse (hot) was 27 °C. The average wingspan for the hot temperature was 4.5 cm. The room temperature was 21 °C and the average wingspan in this temperature was 4.1 cm. The average chrysalis size in hot was 2.5 cm, while the average chrysalis size for room temp was 3 cm. The refrigerator temperature was 16 °C and we found that no butterflies emerged from these chrysalises.

(Photo: Humboldt Jr. High School)

Analysis

From the results I can see that the wing span of the monarch butterflies in the hot are larger than the ones in room temperature. The size of the chrysalis in the hot is smaller than those in room temperature, however. It is strange that in the hot they have smaller chrysalises, yet their wing spans are larger than those in room temperature.

*Some of the chrysalises kept in the hot temperature were weird, they were brown. The cold ones did not emerge.

*If I were to repeat this experiment, I would do more chrysalises and have their exact ages.

Conclusion

I wanted to see if the temperature would affect the size of monarch butterflies. The wingspans of the butterflies that emerged from chrysalises kept in the hot temperature were larger than those from chrysalises kept in room temperature. Yes, my results support my hypothesis. Two additional things that I learned from this experiment were how to care for larvae and how to measure them.

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