What are Insects?

There are more insects on earth than any other group of animals. Over one million different species have been found so far, but there may be as many as 10 million! Their small size and their ability to fly means that insects are found in a wide range of habitats around the world.

Insect body parts

The body of an insect is divides into three parts. The head houses the brain and supports the eyes, feelers, and mouthparts. All insects have six legs on the thorax and many have wings. The abdomen contains the organs for digestion and reproduction.

Common wasp

This insect buzzes around hunting for food. Its black and yellow stripes are a warning that it has a painful sting. In late spring, large wasps can be seen. These are queens who are looking for suitable nest sites. These can be deserted mammal holes, cracks in walls or holes in trees. The nests are made from chewed up wood and wasp saliva which creates a paper-like material. Wasps have a sting to allow them to capture and immobilise their prey (such as aphids, caterpillars, flies and spiders). They may also sting to defend their nest.

Wings

Most wasps have two pairs of wings–one pair of larger front wings and one pair of smaller hind wings. Most female wasps have a stinger that contains venom. As opposed to bees, most wasps do not have much hair on their bodies. Some wasps can land on water and nest near bodies of water, though most are terrestrial. Some wasps are completely black and some, including hornets and the common yellowjacket, have yellow stripes.

Feelers

All insects have two feelers, or antennae, which they use to touch, smell, and taste their surroundings. Antennae are sometimes modified for other purposes, such as mating, brooding, swimming, and even anchoring the arthropod to a substrate. Larval arthropods have antennae that differ from those of the adult. Many crustaceans, for example, have free-swimming larvae that use their antennae for swimming. Antennae can also locate other group members if the insect lives in a group, like the ant. The common ancestor of all arthropods likely had one pair of uniramous (unbranched) antenna-like structures, followed by one or more pairs of biramous (having two major branches) leg-like structures, as seen in some modern crustaceans and fossil trilobites. Except for the chelicerates and proturans, which have none, all non-crustacean arthropods have a single pair of antennae

Eyes

Their two large compound eyes, which have thousands of tiny lenses, mean that insects are excellent at spotting something moving. In addition to their large compound eyes, wasps have several simple eyes known as ocelli, which are typically arranged in a triangle just forward of the vertex of the head. Wasps possess mandibles adapted for biting and cutting, like those of many other insects, such as grasshoppers, but their other mouthparts are formed into a suctorial proboscis, which enables them to drink nectar.

Legs

Insects have three pairs of jointed legs, which they use for walking and gripping. Some insects are also good jumpers.

Mouthparts

Most insects have biting jaws, or mandibles. Behind the jaws are straw-like tubes, which they use to suck up liquid food, such as nectar.

Useful insects

Although some insects are pests, they are important to a lot of living things, particularly flowering plants. They are the main source of food for many animals, and humans find some insects useful, too.

Silk moths

Silkworms spin a silk cocoon around themselves when they are ready to change into the adult moth. People have used this silk to make cloth for more than 5,000 years.

An adult silkworm has a wingspan of 40 to 50 mm (about 2 inches) and has a thick bristly body (the adult female is larger than the adult male). It typically is blond to light brown in colour, with thin dark bands running across the body. The wings are cream-coloured and have dark veins extending out to the margins. Mouthparts in adults are reduced or absent, so in their brief adulthood of two or three days, they do not eat. They cannot fly, either. Males, however, perform a flutter dance, a mating ritual induced by females’ secretion of a pheromone known as bombykol. Females lay about 300 to 500 eggs, which hatch within roughly 7 to 14 days when kept at temperatures of 24 to 29 °C (about 75 to 85 °F).

Bees

Bees are flying insects closely related to wasps and ants, known for their role in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey and beeswax. Bees are a monophyletic lineage within the super family Apoidea and are presently considered a clade, called Anthophila. There are over 16,000 known species of bees in seven recognized biological families. They are found on every continent except Antarctica, in every habitat on the planet that contains insect-pollinated flowering plants.

Some species including honey bees, bumblebees, and stingless bees live socially in colonies. Bees are adapted for feeding on nectar and pollen, the former primarily as an energy source and the latter primarily for protein and other nutrients. Most pollen is used as food for larvae. Bee pollination is important both ecologically and commercially. The decline in wild bees has increased the value of pollination by commercially managed hives of honey bees.

Edible insects

Insects as food or edible insects are insect species used for human consumption, e.g., whole or as an ingredient in processed food products such as burger patties, pasta, or snacks. The cultural and biological process of eating insects (by humans as well as animals) is described as entomophagy. Insects are high in protein and 27 per cent of people in the world eat them. Crunchy crickets are a popular snack.

 

Picture Credit : Google