Watching
butterflies grow through the four stages of their lives - from egg
to caterpillar to chrysalis and finally to winged adult - can be
fascinating. We can enjoy viewing the process ourselves by raising
butterflies in simple homemade cages, and witness their famed metamorphosis
within our own homes.
Female Monarch butterflies
migrate incredible distances, laying eggs along the way. Because
milkweed leaves are the only food that their young eat, this is
the place to look for eggs. Usually only one egg is deposited under
a leaf, and each is as small as a pinhead, so a magnifying glass
is essential for finding them. Magnified eggs are greenish white,
cone-shaped and ribbed. Once you've found one, cut the leaf surrounding
it (at least one inch) and bring it indoors.
This
leaf should be kept fresh on a moist paper towel (without chemical
additives) on a plate or tinfoil tray. Within four days (typically)
after the egg was laid, the baby caterpillar will begin eating its
way out. The "eggshell" provides it with its first meal.
Then it moves on to nibbling small holes in the leaf. Keep it supplied
with fresh milkweed leaves over the next few days, as it will devote
all its time to eating and sleeping - doubling its size in the process.
After about a week in the tray or plate, the caterpillar will be
big enough for a rearing cage where it can move about.
A jumbo-sized glass jar provides suitable
housing. Containers can also be created with screening held in a
cylindrical shape by jar lids and taped, or a half-gallon milk carton
covered (to preserve moisture) in plastic. A small jar of water
should be placed inside and tightly covered with a plastic bag so
the caterpillar doesn't fall in and drown. Poke a stem of milkweed
leaves through the bag. Habitats like these can support up to three
growing caterpillars.
Milkweed leaves should be changed
every day. Caterpillars at this stage are hoarding nourishment for
their pupal stage when they won't eat at all. Their droppings -
which resemble peppercorns - can be cleaned up when their leaves
are changed. When they begin molting - shedding their skin - a twig
should be placed in the container, filling all the available space.
Full-grown
caterpillars are typically about two inches long. Having attained
this size, they begin searching for a place to transform into pupal
form. A caterpillar in captivity will attach itself to the top of
the provided twig with a line of silk spun from its mouth. Slwoly,
it loosens its grip on the twig until it's hanging freely. After
a day and a night of this, it's ready for its final molt. Caterpillars
emerge from this last shedding looking like little green blobs.
Their new skin quickly grows harder and smooth. Towards the end
of its development, you will be able to see the growing butterfly
beneath the transparent membrane. A caterpillar's chrysalis will
typically hang for nine to fifteen days.
Then
comes the dramatic moment when the butterfly stirs and the shell
begins to crack at the seams. Finally it tumbles out in a kind of
gymnastic flip, still clinging to the now-empty chrysalis shell.
A butterfly's wings expand to full size within eight minutes, but
they have to dry before it can fly.
At
this point, having witnessed its miraculous transformation, we should
release our butterfly into the outdoors so it can search for food
and begin to play its part in perpetuating this beautiful cycle.
This time I had 44 caterpillars. They stripped all the leaves from the milkweed
and some have developed it\'s chrysalis, but
some are alive and looking for
more leaves to eat and grow. Do I just have to let them die - or is there something I can feed them? Help!