Insect is a small, air-breathing animal characterized by a segmented body with three main parts-head, thorax, and abdomen. In their adult forms. Insects typically have three pairs of legs, one pair of antennae, and in most instances, two pairs of wings.
For sheer variety and abundance, insects rank among the most successful animals on Earth. About one million species of insects have been identified so far, which about half of all the animals is known to science. Insects live in almost every habitat on land. For example, distant relatives of crickets called rock crawlers survive in the peaks of the Himalayas by producing a kind of antifreeze that prevents their body fluids from freezing solid. At the other extreme are worker ants that forage for food in the Sahara Desert at temperatures above 47 degree centigrade. Insects consume an enormous variety of food. In the wild, many eat leaves, wood, nectar, or other small animals, but indoors some survive on a diet of wool clothes, glue, and even soap. As a group, insects have only one important limitation: although many species live in fresh water-particularly when they are young-only a few can survive in the salty water of the oceans.
Insects are often regarded as pests because some bite, sting spread diseases, or compete with humans for crop plants. Nevertheless, without insects to pollinate flowers, the human race would soon run out of food because many of the crop plants that we rely on would not be able to reproduce. Insects themselves are valued as food in most of the world, except among Western societies. They help to recycle organic matter by feeding on wastes and on dead plants and animals. In addition, insects are of aesthetic importance-some insects, such as dragonflies, beetles, and butterflies, are widely though to be among the most beautiful of all animals.
Insects are invertebrates, animals without backbones. They belong to a category of invertebrates called arthropods, which all have jointed legs, segmented bodies, and a hard outer covering called an exoskeleton. Two other well-known groups and arthropods are crustaceans which include crayfish and crabs, and arachnids, which include spiders, ticks, mites, and scorpions. Many types of arthropods are commonly called bugs, but not every “bug” is an insect. Spiders, for example, are not insects, because they have eight legs and only two main body segments.
Regardless of their size, all adult insects have a similar body plan, which includes an exoskeleton, a head, a thorax, and an abdomen. The exoskeleton protects the insect, gives the body its form, and anchors its muscles. The head holds most of an insect’s sensory organs, as well as its brain and month. The thorax, the body segment to which wings and legs are attached, is the insect’s centre of locomotion. An insect’s large, elongated abdomen is where food is processed and where the reproductive organs are located.
Like other animals, insects absorb nutrients from food, expel waste produce via an excretory system, and take in oxygen from the air. Insect blood circulates nutrients and removes wastes from the body, but unlike most animals, insect blood plays little or no part in carrying oxygen through the body. Lacking the oxygen-carrying portion called hemoglobin that gives the blood of humans and many other animals its red color, insect blood is usually colorless or a watery green Insects have a well-developed nervous system, based on a double cord of nerves that stretches the length of the body. An insect’s brain collects information from its numerous sense organs, but unlike a human brain, it is not in sole charge of movement. This is controlled by a series of nerve bundles called ganglia, one for each body segment, connected by the nerve cord. Even if the brain is out of action, these ganglia continue to work.
In our environment insects are mostly important because they all helps for the balance condition of the ecosystem and maintain environment in good condition , now days many species of insects are in endanger condition because peoples did not understand important and role of insects in our environment. There for we all should have comment sense that is “we should protect all kinds of insects”. In poor country peoples are not understanding why we should safe insects so in that type of country we should provide education about insects, this earth is for all kinds of living things so don’t be selfish be good and make best.
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