Animals Around Us

Types of Insects for Class 3 Science

Insects are the animals with a pair of antennae and two pairs of thin wings. Different insects show variations in their appearance. In this concept, the students will learn about insect habitat, their lifecycle and importance in nature.

After reading the concept, students will be able to:

• State the characteristics of insects.
• Differentiate between useful insects and harmful insects.
• Mention the stages in lifecycle of an insect.
• Give examples for different insect habitats.
• Enlist the insects based on terrestrial habitat and aquatic habitat.

Each concept is explained to class 3 students using descriptions, illustrations, and concept maps. After you go through a concept, assess your learning by solving the two printable worksheets given at the end of the page. This will provide you interesting information about insects. Download the worksheets and check your answers with the worksheet solutions for the concept Types of Insects provided in PDF format.

What Is an Insect?

• 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.

Examples:

   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.

Insect Habitat:

• 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.

Terrestrial 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.
Examples:
   Ants and termites.

Aquatic Habitat:
• Some insects live in water during the early stage of their life cycle.
Examples:
   Mosquitoes and dragonflies.

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.
Examples:
   Bark beetles and weaver ants.

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.
Examples:
   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.

1. 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.
2. 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.

Example:

   The larva of a silkworm and cockroach is called caterpillar and nymph, respectively.
• 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.
3. Pupa Stage: It is called the dormant stage. The pupa covers itself in a covering made of its own saliva and keeps growing.
• 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.

Useful Insects:

• 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.

Harmful 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.

New Words:

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.