Economic importance of Insects.

Economic importance of the insects.

Most people think that the insects are a pestiferous creature and should be destroyed at all cost.But few people knew that exact nature of damage they do. Unfortunately, beneficial acts performed by insects are far outweighed by the tremendous amount of damage done by them.

[I] Injurious insect.

1. Pests of plants,fruits and stored grains.
2. Household pests.
3. Injuries to domestic animals.
4. Disease carrier.
5. Poisonous insects.

1. Pests of plants, fruits and stored grains.

Insect attacks leave, streams, buds, flowers, seeds, fruits, woods, roots, vegetables, wool, feathers, cigars, tools, stored products, and even minerals. Chewing insects like the cabbageworm, hoppers and potato beetles, chewing and swallowed the external part of the plants. Grass and leaves are devoured and even branches are broken by weight.Grasshopper and locusts have invaded the green crops since times immemorial.Locusts, on the war-path, sometimes move on in arms extending for many kilometres. Bark beetles destroy timber in the forest, while the termites damage timber after it leaves the forest.Boll weevils destroy cotton before the harvest. Caterpillars and Japanese beetles strip the foliage from the millions of shady trees every year.

2. Household pests.

Several insects are unwanted guests in the house. Mostly annoying, sometimes they become destructive. Ants, crickets, cockroaches, weevils, fruit flies, and silver flies and feather may be damaged by cloth moths and carpet beetles.

3. Injuries to domestic animals.

They are seriously injured by insects.Most of them live more or less as parasites either externally , such as fleas, lice, bugs, mosquitoes etc.The bird-louse feeding upon the feathers of chickens, cause irritation and loss of flesh. The blood-sucking horn fly is a serious pest of cattle. The grubs of ox warble-fly cut holes in the skin of cattle, thus causing of hiding and flesh. The larvae of the horse botfly sometimes cause serious disturbances in the stomach.

4. Disease carrier.

Many insects play a great role in spreading serious disease on man and domestic animals. They often act as a vector for transmitting various disease producing organisms either by infecting them in bloodstream.eg. malaria, or by contaminating the food such as bacteria.The various species of the genus Anopheles of mosquitoes have been found to convey one or more other parasites protozoa causing human malaria.Certain Culicine mosquitoes spread the nematode worm, Filaria Bancroft, which cause filariasis in man. Similarly, yellow fever is spread by a mosquito Stegomyia ; surra disease among horses, camels, etc of tropical countries by Tabanus fly; African sleeping sickness by Teresa fly; typhoid, diarrhoea, cholera, etc by the common house fly.

5. Poisonous insects.

Many insects and larvae produce poisonous secretions, which are injected into the body of the man and other animals either through a bite or sting. Irritation of skin pain and swelling may results. The common examples of poisonous insects are honey-bee, wasps, hornets, fire ants, bedbugs, mosquitoes and few other larvae.

[II] Productive insects.

Human beings are greatly indebted to certain which supply them with useful products. Many commercial products by insects are indispensable to modern man.Some of them are.

1. Honey.

Honey is produced by the honey bee which serves as human food and medicine.

2. Beeswax.

Wax produces by honeybees is used in polishes, churches, and modelling and to wax the thread. A few scale insects also produce wax.

3. Raw silk.

Silk produced by silkworm and the other insects supply the raw silk in the Orient and Europe. A cocoon yields about 100 feet of fibres, and about 25,000 cocoons and unwind to spin one pound of silk threads. The number of silkworms employed in service of man can be imagined by the fact that nearly 40 million kg silk are used in the world every year.

4. Lac.

The shellac of commerce is obtained from waxy secretions of lac insects or scale insects of India, the female of which secretes lac. It is useful as a foundation of lacquers and shellacs.

5. Dyes.

The dyes known as tannin, cochineal and crimson are derived from the dried bodies of certain scale insects living on cacti. Cochineal is no longer of value since synthetic aniline dyes have largely taken its place.

6. Medical products.

Certain medical products like Cantheridine are also derived from blister beetles.

[III] Helpful insects.

1. Pollinators of flowers.
2. Insects as a food.
3. Insects as medicine.
4. Insects in fine arts.
5. Biology control.

1. Pollinators of flowers.

‘Insect friends’ of man renders him the greatest service in pollination of flowers. Plants depend on upon certain insects for cross-pollination or cross-fertilization which is very necessary for their fertility and the vigour.Various insects and flowers are mutually dependent since many insects feed upon their nectar and pollen grains. Chief pollinating insects are bees, wasps, beetles, ants, flies, etc.

2. Scavengers.

Insects feed upon waste materials such as dead bodies and debris plants and animals, thus preventing decay and obnoxious odours. Some of the common examples of the scavengers are termites, housefly, cockroaches, dung-beetles, many larvae, silverfish.

3. Insects as food.

Insects provide an abduent food supply for animals like frogs, lizards, snacks, fishes, bluebirds , meadow, and house sparrows depend chiefly on insects. Man consumes many insects and their larvae eggs, etc. with their food and fruits. Termites from favourable food in tropics. Green grounds locusts in mortars and made flour of them. American Indians used to dry or smoke larger caterpillars and preserve them for later use.

4. Insects as medicine.

Cochineal insects contain carminic acid, concern, myricetin, fat and fatty acids amino acids are used in the treatment of a whooping cough, neuralgia. Blowfly larvae are used in treatment decay of tissues.Cantheridin oil, made of blister beetles, serves as hair restore.The body extracts of the cocoons of silk moth, Bombyx mori is used for checking profuse mensuration and the treating leucorrhoea and chronic diarrhoea. Bee venom has been used with some degree of success in the treatment of some forms of arthritis. Bee-venom has also been used in the preparation of anti-venom to counteract snake bite.Beeswax is used as a base for ointment.

5. Insects as fine arts.

Insects produce noises in various ways. Whether their sound can be called musical is disputable. In japan, cicadas and crickets are placed in small cages, like birds, in the houses. Tokyo, about 50 markets were dealing with them prior to the war. Japanese celebrate an annual function, the “festival of the singing insects.” Beautiful coloured elytra and wings of some Coleoptera and Lepidoptery are used in crafts by Indians of America, In embroidery, pottery, baskets, metals, alloys, etc. by Red Indians of America, and ear-rings by Jivaros of Equador.

Reference.

Aggarwal Sarita. A Text Book of Biology, New Delhi.: Madhuban Educational Books, 2011.

Bhamrah, H.S., and Kavita, Juneja. A Text Book of Invertebrates, New Delhi: Anmol Publications Pvt Ltd, 2011.

Jordan E.L. and P. S., Verma. Invertebrate Zoology, New Delhi,: S. Chand and Company Pvt. Ltd., 2011.

Kotpal, R. L., Modern Text Book of Zoology: Invertebrates, New Delhi, India: Rastogi Publications,2011.