Tuesday, June 27, 2006

A view of my butterfly garden

As you can see , finally my butterfly garden is taking shape, i'll be posting more photos soon, as the monsoon's have arrived here in kerala, i'm relieved from the duty of watering the plants for the time being.

Saturday, June 10, 2006

Butterfly Pupae


Butterfly Pupa
Butterfly Pupa
When the larva exceeds a minimum weight at a particular time of day it will stop feeding and begin "wandering" in search of a suitable pupation site, usually the underside of a leaf. The larva transforms into a pupa (chrysalis), which then transforms into a butterfly by metamorphosis. To transform from the miniature wings visible on the outside of the pupa into large structures usable for flight, the pupal wings undergo rapid mitosis and absorb a great deal of nutrients. If one wing is surgically removed early on, the other three will grow to a larger size. In the pupa the wing forms a structure that becomes compressed from top to bottom and pleated from proximal to distal ends as it grows, so that it can rapidly be unfolded to its full adult size. Several boundaries seen in the adult color pattern are marked by changes in the expression of particular transcription factors in the early pupa.

Butterfly Pupa
Butterfly Pupa
The pupa of a butterfly is known as chrysalis a term derived from the Greek word khrusos for gold, since a number of butterfly pupae, especially the Nymphalidae have metallic golden markings. The pupal stage is considered as the resting stage. But all transformations for the adult stage are taking place inside the pupa. Hence all the adult organs can be identified in it . but all these structures are firmly glued down to the surface. The abdomen is discernible with 10 segments and at the posterior end, there are generally a number of hooks forming a structure called the cremaster. This is used for the attachment of the pupa to the substrate. Pupa being immobile, is particularly vulnerable to attack by predators. Hence pupation frequently proceeds within a silken cocoon, of hollow of earth or leaf roll as in hesperiidae and some satyridae. The naked pupae are protectively coloured. Such naked puape may hang head – downwards by the cremaster ( tail hooks ) without any other support as in the Danaidae, most of the Satyridae and the Nymphalidae. They may also be attached by the cremaster but supported head- upwards by a silken girdle as in the Lycaenidae, Papilionidae and Pieridae. In both cases, the larva spins a little silken pad into which the hooks of cremaster are firmly embedded. They amy also gain protection by merging into the background and some are able to change their colour to match the surface on which they are resting. Others resemble dead leaves or pieces of twig and the poisonous pupae are usually conspicuous and brightly coloured. Normally the pupae are green or brown.

Adult butterfly emerges from the pupa in about 7 – 15 days. Adults emerge mostly during early morning hours. Adult crawls out by splitting open the pupal case on the back and perch on a suitable place. Immediately after emergence, wings are wrinkled and shriveled and they attain the normal shape soon. The wings get hardened after exposure to the sun. all these actions will be over within an hour. Then the fully opened butterfly will flutter out to find food and mate. At this point, the uric acid accumulated during the pupal period is eliminated in the form of a liquid, meconium, frequently yellow or pink or red. In some parts of the world, numerous drops of meconium sometimes produced following the mass emergence of certain species has given rise to such popular belief as the rain of blood.

Thursday, June 08, 2006

Butterfly Caterpillar


Butterfly Caterpillar
Butterfly Caterpillar
Butterfly Larvae, or caterpillars, are multi-legged eating machines. They consume plant leaves and spend practically all of their time in search of food. Caterpillars mature through a series of stages, called instars. Near the end of each instar the larva undergoes a process called apolysis, in which the cuticle, a mixture of chitin and specialized proteins, is released from the epidermis and the epidermis begins to form a new cuticle beneath. At the end of each instar the larva molts the old cuticle, and the new cuticle rapidly hardens and pigments. Development of butterfly wing patterns begins by the last larval instar. Butterflies belong to the specialized and prolific lineage of holometabolous insects, which means that wings or wing pads are not visible on the outside of the larva, but when larvae are dissected tiny developing "wing disks" can be found on the second and third thoracic segments, in place of the spiracles that are apparent on abdominal segments. Wing disks develop in association with a trachea that runs along the base of the wing, and are surrounded by a thin "peripodial membrane", which is linked to the outer epidermis of the larva by a tiny duct.

Wing disks are very small until the last larval instar, when they increase dramatically in size, are invaded by branching tracheae from the wing base that precede the formation of the wing veins, and begin to express molecular markers in patterns associated with several landmarks of the wing. Near pupation the wings are forced outside the epidermis under pressure from the hemolymph, and although they are initially quite flexible and fragile, by the time the pupa breaks free of the larval cuticle they have adhered tightly to the outer cuticle of the pupa (in obtect pupae). Within hours the wings form a cuticle so hard and well-joined to the body that pupae can be picked up and handled without damage to the wings.
Butterfly Caterpillar
Butterfly Caterpillar
Butterfly larvae ( caterpillars) are quite variable in color and shape. Basically, they have a well – developed head, 3 thoracic and 10 abdominal segments. The head has simple eyes ( ocelli ), a pair of 5 segmented legs or true legs each, which endin a curved claw. The abdomen normally hears 5 pairs of prolegs of false legs on segments 3 to 6 and on 10. the first 4 pairs are called abdominal legs and the last pair the claspers. These prolegs are fleshy, more or less conical, retractile and flattened and have a series of hooks or crochets which help the larva in locomotion. Nine pairs of spiracles or respiratory pores are borne respectively on the prothoracic and irst 8 abdominal segments. The last segment carries a sclerotised plate called surnal plate or button of silk for pupal attachment. The larval skin or cuticle is soft and flexible and may be clothed with spines or setae (bristles) ina few cases.

The larvae mainly feed on leaves of flowering plants. They are very specific in their feeding habits and will usually only feed on a few closely related plant species. Larvae recognize their host plants by certain aromatic vegetable oils, which they contain. It is generally believed that selection may depend upon the detection of chemical attractants in the food species and of repellents in others.

Tuesday, June 06, 2006

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.

Butterfly Eggs
Butterfly Eggs
The egg is the fertilized ovum of the female. Butterfly 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.

Butterfly 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.

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