Resources and conversation on PreK to 2 science
Collards and Caterpillars
Community, assemblage, network,
complex, interdependent, web, and synergism—definitions of an ecosystem
often include these words to highlight
the dynamic interrelated workings of
plants and animals with their physical environment. Young children
don’t understand the complexities
of ecosystems, but they can begin
to understand that only certain food
sources meet the needs of an insect
species, part of the National Science
Education Content Standard C, Life
Science, Characteristics of organisms,
life cycles of organisms, and organisms and environments.
The cabbage white butterfly (Pieris
rapae) is common throughout much
of North America. Food growers
consider it a pest because its larvae eat
leaves of the Cruciferae (also known
as Brassicaceae) family, such as cabbage, broccoli, collards, and kale.
But to the early childhood teacher,
it is a convenient way to teach about
ecosystems. Plant a few flowering
annuals along with a row or pot of
collard greens seedlings, and you will
probably see these white-to-cream
colored butterflies dancing around
the plants within a week. The flat open
leaves of collards make it easier to find
caterpillars and eggs.
Later you may see holes in
the leaves and find bright green
caterpillars on the underside of
the leaves. They are hard to see
because they are almost the same
color as the leaf and have few markings. The larvae hatched from tiny
oval eggs, singly attached to the
leaf by the female butterflies as she
18 Science and Children
laid them. You may find both eggs
and larvae on the plants because
eggs are laid throughout the summer. When venturing outside
with students, even into a
garden, check with parents
for allergies and know the potential stinging or biting organisms in
your area.
Asking questions will focus students’ attention on the interrelatedness aspect of ecosystems: What do
the butterflies eat? What do they drink?
What other living things do they share
food and space with? What do their
babies eat? What eats them? Do their
daily actions affect other living things
as they interact? Look for answers
to these questions by observing the
butterflies through all life stages.
Ask your students, “What do you
see in the collard patch today? Has
anything changed since last time?”
Observations such as, “I touched an
egg on the leaf and it squished,” or
“Two butterflies are going around the
collards,” can be quickly dictated to
an adult to record them in a notebook
or documented with student drawings. Counting visible butterflies,
eggs, larvae, and other animals or the
number of holes in a leaf are ways to
take note of animals in the ecosystem
and to notice any changes. If the
number of caterpillars decreases, is it
because some crawled away or were
they eaten by another animal?
Over several weeks of making observations, students will find out that
the needs of adult insects differ from
the needs of the larvae. To see that the
caterpillars will eat only some kinds of
leaves, bring a few caterpillars into the
classroom in a container. When they
form pupae, the class can observe
this intermediate life stage and the
next—butterflies.
Peggy Ashbrook (scienceissimple @
yahoo.com) is the author of Science
Is Simple: Over 250 Activities for
Preschoolers and teaches preschool
science in Alexandria, Virginia.
Resources
National Research Council (NRC).
1996. National science education
standards. Washington, DC: National Academy Press.
Wright, A.B. 1998. Peterson first guide to
caterpillars of North America. New
York: Houghton Mifflin.
Collards and Caterpillars
Objective:
To notice the interrelatedness of the cabbage white butterfly and the Cruciferae or Brassicaceae family of plants.
Materials:
•An insect field guide
•Cabbage white butterfly (Pieris rapae) caterpillars
•A wide-mouth container to house the caterpillars
•Cloth or paper towels for lid
•Rubber bands
•Plastic cup and lid
•Collard leaves (Brassica oleracea var. acephala)
•Leaves from a plant that is not in the Cruciferae or
Brassicaceae family, such as grass or oak tree leaves
•Cotton balls for water
1. Locate cabbage white butterfly larvae on the leaves
of a brassica plant and observe them eating.
2. Brainstorm with the students about what the
“butterfly babies” will need if they visit the classroom for a few weeks. The discussion usually
reveals that they do not need parental care but
do need food, water, and the “right” temperature.
A few children may mention the need for air.
Discuss that you will be taking the caterpillars
out of their ecosystem and there are most likely
things that you don’t even know about that will
be affected. When deciding how many caterpillars to bring inside, ask, “What would happen if
all the cabbage white caterpillars were removed
from their ecosystem?” Although this species is
far from endangered, it is good to practice having
a minimal impact on any species studied.
3. With the children, set up an insect habitat for a
few cabbage white caterpillars using a clear plastic
pretzel jar or other container. Wash the container
thoroughly. To allow air exchange, cover the
opening with a paper towel or cloth held on with
a rubber band.
4. Set up food for the caterpillars. For convenience,
feed the caterpillars with a bouquet of small collard leaves set in a container with the stems in
water. Have the students carefully wash the collard leaves before putting them in the container.
A clear plastic cup with a carry-out lid works well
because the water level is visible and leaf stems
can be inserted through the opening (but it’s too
small to allow caterpillars to fall into the water).
5. Put additional leaves such as grass or oak tree
leaves in the container to see if the caterpillars
will eat them.
6. Students can sprinkle a few drops of water into
the habitat every day or put in a fresh wet cotton
ball to provide a source of water.
7. Watch the caterpillars move, eat, and excrete.
Record the number of holes in leaves, the number
of leaves consumed, and what kind of leaf is being
eaten. The larvae will pupate and form chrysalides within approximately two weeks. The change
to pupae most likely won’t happen when anyone
is watching. The caterpillar will shed its skin and
the new skin will look different.
8. As butterflies emerge from their chrysalides in about
10 days, release them near the collard patch.
After this introductory activity, children will eagerly find other caterpillars. Remind children not to
pick up caterpillars without asking an adult first, to
protect children and caterpillars. Remind them
that the cabbage white caterpillars did not eat
the “other” leaves, and ask, “What kind of leaf
does this kind of caterpillar eat?” and be ready to
search for the answer using field guides (see Resources
on previous page).
Children can eat caterpillar food, too! They enjoy
washing, cutting, and seasoning the collard leaves,
and eating them after an adult does the cooking.
April/May 2007 19
Teacher’s Picks
What’s happening at http://science.nsta.org/
earlyyearsblog.
How do you entice teachers to use a
school garden program?
Our PreK–4 students helped us plant
a garden plot last spring and will do
the same again this year. Each child
saved a milk carton and washed it
out carefully with the teacher’s help.
Then the teacher cut off the top of
the carton. Every student planted
three radish seeds. Containers
were placed in direct sunlight and
observed daily. Once the plants
sprouted, we transplanted them into
a 5×7 garden plot marked into onefoot squares. Finally, in a few short
days the children harvested radishes.
What a surprise to find such a large
red root vegetable under the ground.
As the radishes grew outside in the
Sun, students saved apple cores,
lettuce leaves, and any other items
from the school cafeteria that would
turn to compost. They placed them
in a pile outside and observed the
compost pile throughout spring
until the end of school. They used
hand lenses to observe pill bugs and
earthworms. They learned that the
fruits and vegetables turned back
to rich soil thanks to all the help of
the pill bugs and earthworms. This
year we will use the compost to
add to our garden before planting.
Mary Leveron
Science Lab Facilitator,
Velasco Elementary
Freeport, Texas
Read more and join the conversation at http://science.nsta.
org/earlyyearsblog.
20 Science and Children
Yvonne Fogelman is currently working on starting
a family science and math program for preschool
through second-grade in Athens, Georgia. She finds
that children enjoy learning about science and believes
that all children benefit from the experience of caring
for a garden. Here are her picks of books to read to
children about gardens and the ecosystems in them.
Yvonne Fogelman
Books
Flower Garden. Eve Bunting. 1994. Harcourt Brace.
A young girl and her father buy flowers at the grocery store to plant into a
windowsill garden as a birthday surprise for her mom. For the many children
who don’t live in houses with yards, this is a good resource to show that even
apartment dwellers can have a garden.
Sunflower House. Eve Bunting. 1996. Harcourt Brace.
A young boy and his father plant a sunflower playhouse for him and his friends
to play in; it lasts for the summer, but then the flowers start to die. At first the
children are sad and try to fix the sunflower playhouse but then realize that
they can take the seeds and plant a new garden next year. As they stuff the
seeds into their pockets, some seeds fall and birds swoop down to eat them.
Use this to illustrate one route seeds travel.
Planting a Rainbow. Lois Ehlert. 1988. Harcourt.
A little girl and her mom plant flowers in a rainbow of colors. The
illustrations show how different bulbs, corms, and rhizomes are
planted at different depths.
Pumpkin Pumpkin. Jeanne Titherington. 1986. Greenwillow.
This is a good resource for explaining to preschoolers how pumpkins grow.
Animals in the ecosystem appear in the illustrations.
Who Eats What? Food Chains and Food Webs. Patricia Lauber. 1995. Harper
Collins Children’s Books.
Have second graders draw their own food chains after reading the descriptions in this book, including one of a leaf-caterpillar-wren-hawk food chain.
Internet
Garden Mosaics Collards Science Page
www.gardenmosaics.cornell.edu/pgs/science/english/collards.aspx
Click on “print version” to print a two-page information sheet all about
collards with activities to try.
KidsGardening.org
www.kidsgardening.com/Dig/digdetail.taf?Type=Art&id=1731
The National Gardening Association’s website features many resources,
such as this article about a first-grade class using the garden as the
context for their writing and reading.