The Effect of Temperature on Monarch Growth (Athena Meltzer)

Research Question and Hypothesis

Research Question: How does temperature affect the rate of chrysalis development?

Hypothesis: If the temperature of the environment the chrysalis is in stays constant, the butterflies will grow and pupate at a faster rate than those in a fluctuating temperature.

Standards

HS-LS2-6 Evaluate the claims, evidence, and reasoning that the complex interactions in ecosystems maintain relatively consistent numbers and types of organisms in stable conditions, but changing conditions may result in a new ecosystem.

HS-LS2-1 Use mathematical and/or computational representations to support explanations of factors affecting the carrying capacity of ecosystems at different scales.

Experimental Design

Students will observe and record the growth in monarch chrysalis' that pupate in environments with a constant temperature and compare them to monarch caterpillars that pupate in their natural environment and fluctuating temperature. Under normal conditions the pupation time of this species is about 10-14 days. Therefore, the students will conduct this investigation over about a two week period. In the end, students will analyze their data and determine if exposure to a constant temperature would result caterpillars that grow and pupate faster than those in fluctuating temperatures.

Independent variable

The independent variable will be temperature. The monarchs in the natural environment will be exposed to daily temperatures from 60 degrees farienheight at night to about 80 degrees farienheight at night. The test monarchs will be in boxes that are inside the house with the temperature staying constant at 72 degrees

Dependent variables

The dependent variable will be the rate of growth measured in the caterpillars growth from egg to butterfly.

Series

The rate of growth (dependent variable) as a function of the temperature (independent variable) until the time of pupation (10-14 days) (series).

Constants and Controls

Constant: The number of monarch caterpillars in each container. The amount of milkweed available, size of container, amount of light available (this will depend on the time of year).

Control: Our control group will be the monarch's that are raised outside in the natural environment.

Materials

1. Twenty Monarch eggs (can be found on milkweed plants. Note, those from a nursery are often sprayed and the monarchs may be infected with the OE fungus).

2. Enough native milkweed plants to feed 20 caterpillars.

3. 20 16 oz plastic cups labeled 1-20

• Place one egg into each cup with a slightly damp paper town and milkweed (even better if you see the female lay the egg and can note that time the egg was laid.

• Make sure you keep the amount of milkweed the same (weigh the amount placed in container each day)

• make sure cups are deep enough so when butterfly emerges, there is enough room for the butterfly to hang and dry its wings

4. Mesh to cover the top of cup so monarch caterpillar can form chrysalis

5. clear box large enough to fit cups in one layer along the bottom.

6. String

7. Ruler

8. Journal with data table to record data

8. Heating pad with low setting

9. Thermometer to measure inside temperature of containers as well as outside temperatures (my use a phone app for outside temperatures at different times during the night)

Procedures

1. Record the day the egg was laid (if possible). All monarchs in study should begin as eggs.

2. Check eggs each day for any changes.

3. Be sure to make note of the temperatures each hour (use an app for the outside temperatures and keep the inside of your house at a constant temperature).

4. Record the day the each monarch egg hatched.

5. Record the day each monarch formed its chrysalis

12. Observe monarch each day and record any changes

13. Record the day each monarch hatches. As the monarch is drying out its wings, make note of any observations.

13. Two hours after hatching, using your string, measure the length and width of each wing and note if the butterfly is male or female.

14. You may let the butterfly go and then measure the container. Carefully remove the chrysalis and measure that to get the weight of the butterfly.

15. Do this for all 20 butterlfies

16. Make a graph of time it took for egg to form chrysalis and then for monarch to pupate into butterfly.

Sample data and graphs

*Because I have not yet done this with my students, I do not have any sample pictures or graphs. I started this at home but all my monarchs were infected with the OE fungus and had to be destroyed

Analysis & Conclusions

I have done this in a much less controlled environment (like in the pictures above) and found that the monarchs that were raised in a controlled environment, overall were larger than those that were left in their natural environment.

Photos & Movies

Monarch caterpillars forming their chrysalis in their natural

environment.

Enclosure I built to protect the monarch

caterpillars as they fed on milkweed. As

they become ready to form their chrysalis

they will climb to the top of the enclosure and "spit out"

the silk platform and "button" that they hang from.

1. This experiment was done in September of 2012. At the 5th instar stage, Monarch caterpillars were placed in a container and set inside where the temperature was constant.

2. These caterpillars formed their chrysalis on average 3 days earlier than the caterpillars that were left in their natural environment that would cool down at night.

1. 2.

3. The monarch's that were raised in a warmer environment.

3.

References

Growth and Development of Monarch Butterflies