Butterfly Egg

Butterfly eggs consist of a hard-ridged outer layer of shell, called
the chorion. This is lined with a thin coating of wax which prevents the
egg from drying out before the larva has had time to fully develop. Each
egg contains a number of tiny funnel-shaped openings at one end, called
micropyles; the purpose of these holes is to allow sperm to enter and
fertilize the egg. Butterfly and moth eggs vary greatly in size between
species, but they are all either spherical or ovate.
The egg is the fertilized ovum of the female. The eggs are commonly yellow
or green in color and may darken just before hatching. The shape of the
egg may be spherical or oval and flattened. The chorion ( egg –
shell ) is often beautifully reticulated / sculptured with ribs or pits.
The egg is slightly depressed at the top and a small opening or micro
Pyle is situated in it. Through the micro Pyle, the sperm enters the egg
for fertilization and after the eggs are laid, air and moisture for the
developing embryo pass through the micro Pyle only . egg yolk provides
the food for the developing embryo.
Eggs are always laid on or in the immediate vicinity of plants or any
other food resource suitable for larval feeding. They are laid singly
or in clusters, mostly on the upper surface of leaves or any part of the
plant and a few species of butterflies scatter their eggs at random as
they fly over vegetation. Frequently, eggs are laid on the undersurface
of the leaf to protect them from rain, direct sunlight and to some extend
predators. The female usually glues the eggs to the surface of the leaf
or any substrate with a viscous secretion from her body. Female butterflies
select the food plants for egg laying both by chemical and visual cues.
Species of danaidae scratch the leaf to confirm the identity before laying
eggs. Females avoid plants that already have eggs laid on them. Thus ensures
that food is there for her eggs only.
The fully formed embryo of the developing larva can be seen through the
transparent chorion, just before hatching. The young larva gnaws its way
through the shell and after hatching, it eats the shell as it contains
nutrients essential for the larva. After eating the shell, the larvae
will start devouring the food plant. Generally the egg period lasts for
3 – 4 days.
when the egg hatches the Butterfly
Larvae comes out
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