Study of Cocoons and Selection of Earthworms for Vermicomposting

Topics: Composting, Earthworm, Compost Pages: 5 (1362 words) Published: December 15, 2013
Study Of Cocoons.
A pupa is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago.

Pupa of the rose chafer beetle
Characteristics:-
In the life of an insect the pupal stage follows the larval stage and precedes adulthood (imago). It is during the time of pupation that the adult structures of the insect are formed while the larval structures are broken down. Pupae are inactive, and usually sessile (not able to move about). They have a hard protective coating and often use camouflage to evade potential predators. Chrysalis? What is it?

It is a different name give to the inner cocoon of insects especially butterflies. In brief- When the caterpillar is fully grown, it makes a button of silk which it uses to fasten its body to a leaf or a twig. Then the caterpillar's skin comes off for the final time. Under this old skin is a hard skin called a chrysalis.

What is a cocoon?
Moth pupae are usually dark in color and either formed in underground cells, loose in the soil, or their pupa is contained in a protective silk case called a cocoon. It is important to differentiate between pupa and cocoon. The pupa is the stage between the larva and adult stages .A cocoon is a silk case that moths, and sometimes other insects, spin around the pupa. Cocoons may be tough or soft, opaque or translucent, solid or meshlike, of various colors, or composed of multiple layers, depending on the type of insect larva producing it. Many moth caterpillars shed the larval hairs (setae) and incorporate them into the cocoon; if these are urticating hairs then the cocoon is also irritating to the touch. Some larvae attach small twigs, fecal pellets or pieces of vegetation to the outside of their cocoon in an attempt to disguise it from predators. Others spin their cocoon in a concealed location – on the underside of a leaf, in a crevice, down near the base of a tree trunk, suspended from a twig or concealed in the leaf litter. The silk in the cocoon of the silk moth can be unravelled to get silk fibre which makes this moth the most economically important of all Lepidopterans. The moth is the only completely domesticated Lepidopteran and does not exist in the wild. Insects that pupate in a cocoon must escape from it, and they do this either by the pupa cutting its way out, or by secreting fluids that soften the cocoon. Some cocoons are constructed with built-in lines of weakness along which they will tear easily from inside, or with exit holes that only allow a one-way passage out; such features facilitate the escape of the adult insect after it emerges from the pupal skin.

Selection of Earthworms for Vermicomposting...
Vermicompost is the product or process of composting using various worms, usually red wigglers to create a heterogeneous mixture of decomposing vegetable or food waste, bedding materials, and vermicast. Vermicast, also called worm castings, worm humus or worm manure, is the end-product of the breakdown of organic matter by an earthworm. The earthworm species most often used for composting is the Red Wiggler. We will talk briefly about this earthworm below....

Eisenia fetida, known under various common names such as redworm, brandling worm, panfish worm, trout worm, tiger worm, red wiggler worm, red californian earth worm, etc., is a species of earthworm adapted to decaying organic material. These worms thrive in rotting vegetation, compost, and manure; they are epigean. They are rarely found in soil, instead preferring conditions that are inimical to some other worms. In this trait they resemble Lumbricus rubellus. They have groups of bristles (called setae) on each segment that move in and out to grip nearby surfaces as the worms stretch and contract their muscles to push themselves forward or backward. Eisenia fetida worms are used for vermicomposting. They...
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