Lifecycles of Butterflies
Lesson 6
Silk Spinning
In this lesson students continue to observe the caterpillars in their habitat. The focus is to understand silk spinning. This lesson is contingent upon the spinning of silk by the caterpillar, so look for it. The lesson may need to be rearranged with lessons 4 and 5, but should not be skipped.
3. Lesson set up and Management
INQA: Scientific investigations are designed to gain knowledge about the natural world.
INQD: Simple instruments, such as magnifiers, thermometers, and rulers provide more information than scientists can obtain using only their unaided senses.
SYSA: A system is a group of interacting parts that form a whole.
LS1B: Animals have life cycles that include being born, developing into children, adolescents, then adults, reproducing (which begins a new cycle), and eventually dying. The details of the life cycle are different for different animals.
LS3A: There are variations among the same kinds of plants and animals.
LS3B: The offspring of a plant or animal closely resembles its parents, but close inspection reveals differences.
Caterpillars produce a liquid protein that becomes a solid fiber (silk).
Caterpillars use silk to create a shelter.
3. Lesson set up and Management
Materials:
An Activity Sheet 5, A Caterpillar and Its Silk is available to reproduce, but this is a sheet that can be done just as easily on a science notebook page. Be sure, as always, to head and date science notebook pages. Check to be sure there is silk to observe for this lesson.
Procedure:
Distribute caterpillars and hand lenses and allow students to observe. Point out the presence of silk. Give students the opportunity to draw a labeled diagram of what they see and discuss how the caterpillar makes silk and uses it.
If some students don't have silk to observe, allow them to see what's going on in caterpillar cups where it is present.
Be on the lookout for any caterpillars that are forming a "j-shape" as they hang. This is a sign that the caterpillars will soon form chrysalises. It happens very quickly so once the "j-shape" is seen, watch the caterpillars very closely.
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Caterpillars "J-ing" prior to forming a chrysalis. |
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Flight cages need to be assembled to be ready to accommodate the chrysalises as they form. Each chrysalis needs to be transferred.
Background Information: The caterpillar produces liquid protein from spinnerets in the mouth area that becomes solid fiber. It swings its head from side to side to make and attach this silk. This silk gives the caterpillar a place to move and anchor itself at various times. In nature, the silk serves to "knit" a leaf together into a little tent to shelter the caterpillar.
Silk in caterpillar cup.
Writing Support:
No writing support for this lesson.
Reading Support:
In Appendix B on page 101 of the Teacher's Guide (2002 version) there is an interesting article about the production and use of silk from silkworm caterpillars.