Common Insect in Bangladesh

Insects:

(Class Insecta) are a major group of arthropods and the most diverse group of animals on the Earth, with over a million described species—more than all other animal groups combined.^[1] Insects may be found in nearly all environments on the planet, although only a small number of species occur in the oceans where crustaceans tend to predominate instead. There are approximately 5,000 dragonfly species, 2,000 praying mantis, 20,000 grasshopper, 170,000 butterfly and moth, 120,000 fly, 82,000 true bug, 360,000 beetle, and 110,000 bee, wasp and ant species described to date. Estimates of the total number of current species, including those not yet known to science, range from two million to fifty million, with newer studies favouring a lower figure of about six to ten million.^[1][2][3] Adult modern insects range in size from a 0.139 millimetre Mymarid wasp (Dicopomorpha echmepterygis) to a 55.5 centimetre long Stick insect (Phobaeticus serratipes).^[4] The heaviest documented insect is a Giant Weta (at 70 grams), but other possible candidates include the Goliath beetles Goliathus goliatus, Goliathus regius and Cerambycid beetles such as Titanus giganteus, though no one is certain which is truly the heaviest..Arthropods are characterised by having the following features:a hard external skeleton (called a exoskeleton)a segmented bodyat least three pairs of jointed legsThe Arthropoda is divided into a number of classes.

These include the :

Crustacea (crabs, crayfish, prawns),

Arachnida (spiders, mites, scorpions),

Myriapoda (millipedes & centipedes),

Insecta (insects)

The insects have proved to be the most successful arthropods. There are far more species in the class Insecta than in any other group of animals. These amazingly diverse animals have conquered all the environments on earth except for the frozen polar environments at the highest altitudes and in the immediate vicinity of active volcanoes.

Insects play a very important role in the web of life, in every environment. Some of their jobs include pollinating flowering plants, being a source of food for insectivorous animals and assisting in the decomposition of plants and animals.