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Lesson 1, Data Collection and Record Keeping.
Measuring Larval Growth and Development |
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Background
Two of the most important scientific skills are making detailed measurements and
keeping careful, organized records of these measurements. As your students rear their
larvae, they will learn a great deal if they practice these skills. We have developed data
sheets and measurement techniques that will help them to do this.
Materials
Monarch Daily Observation sheets
(student handout - 2 pages, 1 per student or student group; data for each larva are kept
on a separate sheet)
Rulers with mm marks clearly visible; clear plastic ones work best
Balance accurate to the nearest mg is highly desirable; you may be able
to borrow one from a high school or other source
All of the materials required to rear larvae
Monarch Class Data Sheet (student
handout page: you can keep a single copy for the entire class, and when it is complete,
copy it for individual students or groups of students)
Optional: large wall calendar or calendar drawn onto butcher paper for
class monarch calendar
Procedure
Tell students they will keep detailed records of the growth and
development of their larvae. Hand out Monarch Daily Observations charts and monarch
eggs or larvae. Do the first observations together. If you do not have an accurate balance
for weighing larvae, just record their lengths.
Have students fill in their Monarch Daily Observations chart
daily or every other day during the larval stage, and every 4-5 days during the pupa
stage. At the end of each stage, fill in the summary section for that stage. To move pupae
so that it is possible to weigh them and to measure adult winglengths, see Rearing and
Observing Techniques in the HOW-TO’s section.
When butterflies emerge, summarize all data on the Class Data
Sheet.
Use the class data to answer questions about monarchs. Students can
think of questions that interest them, or you can use the following list. In many cases
you will need to make a graph to answer the questions. Whether you do this as a class or
as individuals depends on the age and abilities of your students.
- Do large caterpillars produce large butterflies?
- Which are larger, females or males?
- Do males or females emerge sooner from the chrysalis?
- Do larger caterpillars take longer to pupate?
- What was the average length of time in the pupa stage?
- What is the sex ratio of the monarchs our class raised?
- How much growth (either mass or length) occurs in a single day at the
end of the larval period?
- If desired, record life cycle data on a class
calendar. Make a drawing for each monarch every day, so that the calendar shows when they
form a "J", when they pupate, and when the adult butterflies emerge. You could
use a separate calendar for each caterpillar, or show all individuals on one calendar.
Worksheets
The following are examples of the worksheets necessary for this lesson.
You may print them directly from the site. If you experience problems, please
email us at webadmin@monarchlab.org
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ã 2000 Monarchs in
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