|
Butterfly Life History
The life story of a butterfly is called its life history or metamorphosis.
Characteristically, butterflies undergo major developmental changes during
their growth. For example, the butterfly lays eggs which hatch into creeping
forms with chewing mouth parts. These are called caterpillars or larvae.
Incidentally, the word caterpillar is derived from two latin words, catta
pilosa, meaning ‘hairy car’ which is quite descriptive of
some kinds. But butterfly larvae are not hairy. During this stage, the
butterfly feeds and grows. As a matter of fact, it is only during the
larval stage, that actual growth occurs, and a caterpillar’s only
aim in life is to feed and store up food. As it increases in size, however,
the number of cells in the body does not increase; they merely become
larger. When full grown, the caterpillar sheds its skin and transforms
into a pupa. This is called chrysalis in the case of butterfly. When this
transformation occurs, the larval cells begin to die and clusters of adult
cells, which have so far been quiescent, are stimulated into growth cells,
which have so far been quiescent, are stimulated into growth by hormones
or chemical regulators secreted by glands in the head and thorax.
During the pupal stage, the larval tissues are torn down and slowly rebuilt
into organs more fitted for aerial life. When the chrysalis is mature,
the wings and legs of the future butterfly can be seen through its transparent
skin. The developed butterfly crawls out by splitting open the chrysalis.
At first, its wings are mere fluid filled sacs, but these rapidly expand
and harden, and the adult winged butterfly is then ready fro flight. It
no longer has mouthparts fitted fro chewing leaves; they are now tube
like and are used only for siphoning nectar from flowers. There is no
growth during the adult stage. Thus the life history of a butterfly has
four stages, egg, larva, pupa and adult and is said to have a complete
life history or metamorphosis.
Diagram showing the life cycle of a butterfly :- Butterfly
Life Cycle
|