Animals Around Us
Concept: All About Insects
What are insects?
- Insects are a group of small creatures found around us. This group of the animal kingdom comprises the largest variety of creatures.
- Their existence is both useful and harmful for humans.
Example : Cockroach, ant, honey bee, etc.
Characteristics of insects:
- They lack a backbone.
- They have a hard shell-like external structure called an exoskeleton.
- An insect's body can be divided into three parts—head, thorax, and abdomen.
- Insects have antennae that are meant for sensing smell and any movement in the surroundings.
- They have a compound eye.
- Insects have three pairs of legs and two pairs of wings. The end part of the legs is equipped with claws that can hold any surface tight.
- They lack lungs, and they exchange gases through holes on their body called spiracles.
- The sting is a hook-like structure seen at the end of the abdomen. Insects pierce this sting in the body of an intruder when they sense danger. Most insects use this as a defence mechanism. The stings of insects are generally poisonous.
Habitat of insects:
- Insects are adapted to live in every habitat like land, water, forests, mountains, deserts, etc.
- The habitat should provide sufficient food resources and appropriate breeding grounds for the insects.
- Some insects change their habitat based on the phase of their life cycle.
- Land as habitat:
- Many insects are adapted to build mounds on land.
- These mounds are made using mud or soil, water and the saliva secreted by the insects.
- Water as a habitat:
- Some insects live in water during the early stage of their life cycle.
- Tree as a habitat:
- Some insects can drill through the tree trunk and make a shelter for survival.
- Leaves of trees are bent and folded by some insects to make a nest-like structure.
- Hives as a habitat:
- Some animals live in groups. A group of insects is called a colony.
- Animals make unique structures called hives, where many insects live together.
- These hives are made using mud or wax. Hives are used both for storing food and laying eggs.
- Hive-like structures made by wasps are called paper nests.
Example : Ants and termites.
Example : Mosquitoes and dragonflies.
Example : Bark beetles and weaver ants.
Example : Honeybees and wasps.
Lifecycle of insects:
- The life cycle of an insect can be divided into three or four stages.
- Moulting and metamorphosis are prominent phenomena in the lifecycle of an insect.
Let us discuss the life cycle of an insect in brief.
- Egg stage: Insects lay a large number of eggs at a time. These eggs take some time to hatch or mature, which varies from insect to insect.
- Larval stage: Once the eggs are matured, hatchlings come out of them and start feeding. This stage is called the larval stage.
- The larvae of different insects are known by different names.
- The larva shed their skin multiple times by the phenomenon of moulting to grow into a pupa.
- The phenomenon of growing into a pupa and then into an adult is called metamorphosis.
Example : The larva of a silkworm and cockroach is called caterpillar and nymph, respectively.
- The structure in which the pupa grows is called a cocoon.
- On maturation, the adult insects come out of the cocoon.
Lifecycle of ants:
- Ants live in colonies. Their colonies comprise male and female worker ants and a queen ant.
- Male worker ants are smaller in size, whereas female worker ants are larger.
- Their main function is gathering food, repairing the mound, taking care of eggs/larvae, and protecting the colony from intruders.
- The queen ant lays a large number of eggs at a time which hatch to form new ants.
- Ant undergoes three stages of development like other insects, i.e., egg, larval, and pupa.
- The Dung beetles push the dung balls into the soil and help fertilise the soil and clean the surrounding.
- We get honey and wax from the honeybees.
- Honeybees, butterflies, moths, etc., visit different flowers and help in pollination.
- Praying mantis feeds on grasshoppers, crickets and other harmful insects that destroy vegetation.
- The ladybugs prey upon many plant-sucking pests.
- The silk used to make garments is obtained from cocoons of silkworms.
- Larvae of dragonflies control the population of mosquito larvae in water, and adult dragonflies feed on flying insects.
- Insects like locusts damage hectares of agricultural farms in no time.
- Tree borer beetles damage the trees by digging into its trunk.
- Aphids suck the sap (juice) from the plants and reduce the crop yield.
- Bed bugs and mosquitoes bite humans and suck blood, causing many diseases.
- Wasps and hornets feed on useful insects such as honeybees.
- Termites and carpenter ants damage the wood-based items.
- Silverfish (an insect), cockroaches, moths, etc., damage clothes made of silk and wool.
Moulting: The shedding of the exoskeleton so that the insect can grow.
Metamorphosis: The process of changing of an immature form into an adult form through different stages.
Wax: A yellowish sticky substance made by honey bees.
Intruder: In this case, it means an enemy that can harm the insect.
Did You Know?
- Some predatory beetles can dive deep into the water to hunt for food. There the diving beetles can enjoy all their food without any competition.
- Ants can farm and raise other creatures like fungus, aphids and other insects to get benefits from them.