Wednesday, October 14, 2015

Baby Bugs : Just emerged from the eggs.

Animals have two ways to make sure that they leave offspring in the world, so that their genes survive. One is to have few children and care for each one intensely. The other is to have huge numbers of offspring, so that even though many die enough survives. That is what insects do. Most of those eggs, or the larvae they give birth to, will die in one way or another, so there have to be many of them.

In most insects, life begins as an independent egg. This type is reproduction is known as ovipary. Each egg is manufactured within the female's genital system and is eventually released from her body through an ovipositor, a tube-like, saw-like, or blade-like component of her external genitalia. The egg-laying process is known as oviposition. Each insect species produces eggs that are genetically unique and often physically distinctive as well - spherical, oval, conical, sausage-shaped, barrel-shaped, or torpedo-shaped. Yet regardless of size or shape, each egg is composed of only a single living cell.

In most insects the egg is covered by a protective "shell" of protein secreted before oviposition by accessory glands in the female's reproductive system. This eggshell, called the chorion, is often sculptured with microscopic grooves or ridges that may be visible only under the high magnification of an electron microscope. The chorion is perforated by microscopic pores that allow respiratory exchange of oxygen and carbon dioxide with relatively little loss of water. The micropyle, a special opening near the anterior end of the chorion, serves as a gateway for entry of sperm during fertilization.

A female receives sperm from her male partner during the act of mating. She can store that sperm for long periods of time in a special part of her reproductive system, the spermatheca. As a developing egg moves past the opening to the spermatheca, a few sperm are released onto its surface. The sperm swim toward the micropyle - the first one to reach its destination enters and injects its nucleus into the egg. The sperm nucleus quickly fuses with the egg nucleus to form a one-celled embryo. This event is known as fertilization. After the egg is fertilized, it undergoes a period of rapid growth and development known as embryogenesis, literally the "embryo's beginning".

Many insects pass the winter in the egg stage. Insect eggs are ideally suited for withstanding the hardships of winter. The eggs have shells that are thick and watertight. In many cases the eggs are covered with hairs, silk, or frothy materials produced by the female before she died. These provide an extra degree of protection by insulating the eggs. Most butterfly or moth caterpillars eat their eggshell just after the hatching as they get maximum proteins out of eggshell. But these “Baby Bugs” just crawling here without eating the eggshell.

Yuwaraj Gurjar.

Caterpillar : Greedy eating machines.

Butterflies and moths undergo major developmental changes during their growth. The moth lay eggs, which hatch into creeping forms with chewing mouthparts. These are called as caterpillars or larvae. Incidentally, the word caterpillar is derived from two Latin words, catta pilosa, meaning hairy cat, which is quite descriptive of some kinds. During this stage the moth feeds and grows. 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.

The caterpillar eats through the top of the egg, creative a hole through which it emerges. After hatching, it often eats the eggshell as its first food and this gives it invaluable nutrients. Since this is the only growing stage in a moth’s life, it has to consume as much food and store as much energy as possible. Its jaws works like scissors very rapidly and efficiently and it finishes leaf after leaf on branch after branch. The caterpillar grows rapidly so periodically it has to molt. A moth caterpillar casts off its outer skin layers five times in its life.

Although most caterpillars feed on leaves, there are strict preferences for specific host plants. These strict preferences are dictated by the chemical composition of the plant parts that the caterpillar eats. Therefore, the caterpillar feeding on a particular plant species or set of species will not eat leaves of other species. Some caterpillars may prefer slightly mature leaves, some may refuse to eat anything other than tender ones; most prefer to tender leaves but otherwise eat whichever are available on the plants where their mothers as eggs place them.

The coloring is usually such that the larvae are well camouflaged, and can thus avoid or fool predators. Sometimes there are scary looking eye designs or bristles to frighten the enemy.

When the larva is ready to pupate, it attaches itself to a spot with silk pad and cremaster. After a period of rest, it starts wriggling and makes undulating movements from tail up, until the skin bursts near the head. The skin is then pushed upwards till it gets collected near the tail. The pupa then draws it tail out and by means of some minute hooks in the cremaster, fixes it to a surface again after casting off the old skin. The pupa hang there for some days and then the adult will emerges out of that pupa for a new flying life.

Yuwaraj Gurjar.