The Corn Ear Worm Project:
An Experiment in Factors Influencing the Rate of Metamorphosis
developed by Maya Merritt
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State Objectives |
Competency Goal 1: The
learner will develop abilities necessary to do and understand scientific
inquiry. |
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Time Required |
two 50 minute class periods. Day 1 – set up experiment Day 2 – analyze data and discuss * a
short amount of time will be needed to record insect growth every other
day. In total, expect that 1-2 months
may pass until metamorphosis is complete. |
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Note to Teachers |
The variable in this
experiment is temperature. Other
variables, such as light vs. dark, may also be tested. |
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Resource for Live Arthropods |
Corn Ear |
Observation: The following experiment is based on observations that the rate of insect metamorphosis can be affected by outside environmental factors.
Hypothesis: Corn Ear Worms developing in a 30ºC incubator will complete metamorphosis faster than those developing at 25ºC.
Experimentation Procedure:
Materials:
10 cups filled with food supply and one corn ear worm
thermometer
incubator
ruler
dissecting scope useful, but not necessary
1. Label the cups from 1 – 10.
2. Place cups 6 – 10 into a closed drawer at 25ºC. The reason for this is that the drawer is dark, as is the incubator. This will limit the variable to that of temperature only.
3. Place cups 1-5 into a closed incubator at 30ºC.
4. All cups should be placed so that the food supply is at the top. This helps with water conservation.
5. Make observations every other day looking for evidence of growth including size and/or apparent pupation. A dissecting scope may help in this.
6. Keep an eye on the moisture level as the treatments in the incubator are susceptible to drying out.
Data Collection: Examine the caterpillars every other day for a period of approximately 3 weeks or until all have entered the pupal stage. Record the length of each caterpillar in millimeters. Have students develop a data table to record these measurements.