Sunday, 4 July 2010
History of Butterflies
Butterfly Life History
The life of butterfly is called its life history or metamorphosis. Characteristically, butterflies undergo major developmental changes at their growth time. Such as 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 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.
The American Painted Lady and the Painted Lady (Vanessa cardui) do not overwinter in Minnesota but migrate from the south in the spring. Painted ladies are attracted to open areas with low vegetation and a variety of flowers. The larvae feed on everlastings (Anaphalis spp. ) as well asthistles. The adults prefer pussytoes (Antennaria spp.) and other composites, such as black-eyed Susan and sunflowers.
Monarch (Danaus plexippus) migrates south for the winter. Thenoverwintering in the highlands of Mexico, the overwintering generation flies north to the latitude of Texas and lays eggs. These eggs hatch and the larvae feed. The pupae turn into adult monarchs in 10 to 14 days, and it's this generation that arrives in Minnesota in May and June. During the summer, the migrant adults lay eggs that produce the generation of monarchs that return to Mexico in the fall
Some butterflies have one generation a year. The pupa overwinters and the butterfly emerges in the spring. Only a few, such as Mourning Cloaks (Nymphalis antiopa) over winter as adults. Mourning Cloaks are the first butterflies seen in the spring, feeding on nectar from shrubs such as Amelanchier. Their caterpillars feed on a variety of common trees, such as willows, poplars and elm. They overwinter in barns, tree holes or other protected areas.
At the time of 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. 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 has no longer mouthparts fitted fro chewing leaves; they are now tube like and are used only for siphoning nectar from flowers. There is no growth at the time of adult stage. Thus the life of a butterfly has four stages, egg, larva, pupa and adult and is said to have a complete life history or metamorphosis.
Labels:
Characteristics,
growth,
hairy car,
metamorphosis
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