Monarch Butterfly


The Monarch Butterfly is the only butterfly that migrates!  As the weather gets colder, monarchs begin their annual migration.  Tens of millions of these butterflies spend the winter in a mountain forest in Central Mexico.  Monarchs sometimes cover whole trees of eucalyptus and pine groves.  In the spring they will make the long journey back north, and lay eggs along the way.  When these eggs hatch into caterpillars, the whole cycle starts over again.
Monarch Butterfly Egg…….so small…..the size of a period

Monarchs live for about 9 months, but they don’t always look like butterflies.  The monarch begins its life as an egg.  The eggs, which are laid on MILKWEED leaves, hatch into caterpillars.  The baby caterpillars eat the milkweed and grow very quickly.  The milkweed contains a poison that the monarchs use as a defense.  While the poison doesn’t hurt the monarchs, it makes them taste bad to birds and other predators.  Predators soon learn to avoid the bright colors of the monarch caterpillars and butterflies.

Metamorphosis is the series of developmental stages insects go through to become adults.  Butterflies and moths have four stages of life:  egg, larva (the caterpillar stage), pupa (the chrysalis phase) and adult.  It takes a monarch butterfly just 30 to 40 days to complete its life cycle, with warmer temperatures generally being responsible for faster development.

MONARCH FEMALES lay their EGGS on milkweed, the only plant monarch caterpillars can eat.  The eggs are laid singly and generally on the undersides of leaves.  The eggs are very small (about the size of the periods at the end of the sentences on this page) and are whitish in color.  Three to six days after the eggs are deposited, they will hatch.

Immediately after hatching, the CATERPILLAR is so small it can barely be seen.  It grows very fast though, feeding on nothing but milkweed leaves.  In just 9 to 14 days it is about 2” long and is now full grown.  A caterpillar has eight pair of legs.  The first three pair of legs will later become the butterfly’s legs.
A MONARCH CATERPILLAR SHEDS IT”S SKIN five times during the larval stage.  Similar to the way a snake sheds its skin when its body has outgrown the skin, a caterpillar does the same.  A new, larger skin is always waiting under the one that is shed.

When the caterpillar is full grown it usually leaves the milkweed plant.  It crawls (sometimes 30 or 40 feet from the milkweed) until it finds a safe place to pupate.  The caterpillar makes a silk-like mat and then attaches its last pair of legs to the mat.  The caterpillar allows itself to drop and then hangs there, upside down in a J-shape, for about one full day.

CHRYSALIS:  The caterpillar’s skin is shed for the last time as it passes from the larval stage to the pupa (chrysalis) stage of metamorphosis.  Under the caterpillars skin this time is a jade green casing which is called a chrysalis.  Inside the chrysalis, which is only about an inch long, the caterpillar will miraculously transform into a beautiful butterfly.
Chrysalis…….the unbelievable change from caterpillar to butterfly……wow!

Immediately after the skin is shed, the chrysalis is very soft.  Within an hour though, it hardens to become a protective shell for the developing butterfly.  Dramatic changes occur inside the chrysalis.  The mouth parts must go from being those required for chewing (milkweed leaves) to what a butterfly will need: a straw-like tongue used for sipping nectar from flowers.  WOW!!!……the CREEPY, CRAWLING CATERPILLAR WILL BECOME ONE OF THE MOST BEAUTIFUL FLYING INSECTS ON EARTH!!!!   The MONARCH BUTTERFLY!

In just 9 to 14 days the transformation is complete.  The chrysalis suddenly cracks open and out comes the monarch butterfly.  Its wings are tiny, crumpled and wet.  The butterfly clings to its empty chrysalis shell as hemolymph , the blood-like substance of insects, is pumped through its body.  As the hemolymph fills the monarchs body and wings, they enlarge.  About one hour after emerging, the monarch’s wings are full sized, dry and ready for flying!

This Milkweed is the variety most commonly seen along roadsides, waste places and old fields throughout New England.  Monarch Butterflies lay their eggs on this wild Common Milkweed and other cultivated varieties.






Reference Materials

Monarch Butterflies (Children)
“A New Tree Book”
-Emilie V. Lepthien
Childrens Press – Chicago

Discover Butterflies (Children)
Activity Book
Callaway Gardens
Pine Mtn, Georgia 31822

Butterflies & Moths (Children)
Usborne First Nature
EDC Publishing
Tulsa, Oklahoma

The Butterfly Book
“An Easy Guide to Butterfly Gdns”
D & L Stokes and E. Williams
Little Brown, Boston, MA

The Butterfly Garden
Turning Your Garden, Window
Box or Backyard into a Beautiful Home
For Butterflies, 1985
M Tekulsky
The Harvard Common Press, Boston, MA