Female butterflies lay many eggs during their short life
to insure that even a small number of these eggs will
survive. Caterpillars (butterfly larva) hatch from eggs. The
eggs are usually laid in a protected location on or near the
plants that the soon-to-be caterpillar will eat. Most eggs are
attached to the plant with a fast-drying glue-like chemical
that the female butterfly secretes along with the egg.
Some species lay one egg at a time, others lay eggs in
small clusters, while others lays hundreds at a time.
Eggs are usually laid on the under surface of a leaf or
somewhere near the host plant. For example, the Monarch
butterfly lays its eggs on the bottom of the milkweed plant
which its caterpillar will eat. Other locations are flower
heads, and crevices in tree bark. A few (like ghost moths)
lay thousands of eggs while they fly; the larva of these
species usually eat grass.
Butterfly eggs come in many shapes and colors. The
shapes include spherical, oval, and pod-shaped; the colors
include white, green, and yellow. The eggs have a thin,
tough shell with raised ribs or pits (reticulations). At the top
of each egg is a micropyle, a small pit that marks where the
sperm entered the egg. While the egg is developing, air and
water enter the egg through the micropyle.
There is a yolk inside each egg that nourished the
developing larva. When it is time to hatch, the larva gnaws
open the egg shell with its jaws. After hatching, most
caterpillars finish eating their egg case as their first meal.
After this, the plant upon which the egg was laid will be
A caterpillar is the larval stage of butterflies and moths.
The caterpillar hatches from a tiny egg and will eventually
pupate and turn into an adult butterfly or moth.
This larval stage usually lasts from two weeks to about
a month. This is the main feeding stage of the butterfly.
Caterpillars eat almost constantly and grow very quickly, at
an astonishing rate.
The pupa is the stage in a butterfly's (or moth's) life
when it is encased in a chrysalis and undergoing
metamorphosis. It does not eat during this stage.
The pupa stage lasts from a few days to many months
(some butterflies overwinter in the pupa stage, and the
adult emerges in the spring).
The pupa of a butterfly is called a chrysalis (derived
from the Greek word for gold). The chrysalis of many
butterflies (like the Nymphalidae and Satyridae families)
are suspended from a silk pad and abdominal hooks.
Others (like like swallowtails and sulphurs) also have a silk
girdle supporting their mid-section. About a day before the
adult butterfly emerges, the chrysalis of many species
(including the monarch) becomes transparent.
An adult butterfly emerges full-grown from the
chrysalis, often losing reddish meconium fluid as it leaves.
When the adult emerges, its wings are wrinkled, wet and
deflated, but the abdomen is distended with fluid. The
butterfly pumps some of this fluid into the wings through
veins to inflate them. The butterfly then rests and then lets
the wings dry out. The primary purpose of the adult stage is
to mate and reproduce.
Adults can only eat liquid food through their straw-like
proboscis. Most butterflies only sip flower nectar, liquids
from rotting fruit, mushy bird dung, and mineral-rich water
from puddles (this activity is called puddling). Some
butterflies (like the Zebra Longwing) sip pollen. The
Harvester Butterfly sips the body fluids from woolly aphids
using its proboscis. A few butterflies sip rotting flesh. A rare
few lepidoptera (like the great silkmoth) cannot eat at all;
they die in about a week, after mating and reproducing.