All About Insects | Science Olympiad for Class 3 PDF Download

What Is an Insect?

Insects are tiny animals that live all around us. There are more types of insects than any other kind of animal. Some insects are good for people, while others can be bothersome. Examples of insects include cockroaches, ants, and honey bees.

Special Features of Insects

We all know insects can buzz around, but why? Well, insects have special features that other animals don't, which helps them zip through the air and walk on walls.

• Backbone: Insects do not have a backbone.
• Exoskeleton: They have a tough outer shell called an exoskeleton.
• Body Parts: An insect's body has three parts: the head, the thorax, and the abdomen.
  
• Antennae: They have antennae on their head to smell and sense movement around them.
• Eyes: Insects have special eyes called compound eyes.
• Legs and Wings: Insects have six legs and usually two pairs of wings. The tips of their legs have claws to grab tightly onto surfaces.
• Breathing: Instead of lungs, insects breathe through tiny holes on their bodies called spiracles.
• Sting: Some insects have a sting at the end of their abdomen. They use this to protect themselves by poking it into threats. The sting can be poisonous.

Clear all your Class 3 doubts with EduRev Join for Free

Join for Free

Different Homes of Insects

Can you list insects that live in water during the early stages of their life?

Mosquitoes and dragonflies live in water during the early stages of their life.

• Insect Habitat: Insects can live in many places like land, water, forests, mountains, and deserts. They need enough food and a good place to have their babies. Some insects even move to different places as they grow up.
• Terrestrial Habitat: On land, many insects build homes called mounds out of mud, soil, water, and their own spit. Examples: Ants and termites.
• Aquatic Habitat: Some insects spend the early part of their life in water. Examples: Mosquitoes and dragonflies.
• Tree as a Habitat: Some insects make their homes by drilling into tree trunks or bending tree leaves into nest shapes. Examples: Bark beetles and weaver ants.
• Hives as a Habitat: Insects like to live together in groups called colonies. They build special homes called hives out of mud or wax to store food and lay eggs. Wasps make a kind of hive called a paper nest. Examples: Honeybees and wasps.

Life Cycle of Insects

• Egg Stage: Insects lay lots of eggs at once. These eggs need some time to hatch, and the time it takes can be different for each type of insect.
• Larval Stage: After the eggs hatch, the young insects, called larvae, start to eat. Different insects have different names for their larvae, like caterpillars for silkworms and nymphs for cockroaches. During this stage, larvae shed their skin many times through a process called moulting to grow into the next stage.
• Pupa Stage: This is a quiet stage where the insect, now a pupa, wraps itself in a covering made from its own spit and keeps growing inside this shelter, known as a cocoon. Eventually, adult insects emerge from the cocoon.

For Example: Life Cycle of Ants

• Colony Structure: Ants live together in big groups called colonies. These colonies have male and female worker ants and one queen ant. Male workers are smaller, and female workers are larger.
• Roles of Worker Ants: The main job of worker ants is to find food, fix their home called a mound, take care of the eggs and young ants (larvae), and keep the colony safe from enemies.
• Queen Ant's Role: The queen ant's main job is to lay eggs. She lays many eggs at once, which will grow into new ants.
• Stages of Development: Just like other insects, ants go through three main growth stages: egg, larval, and pupa.

Download the notes All About Insects

Download as PDF

Download as PDF

Useful Insects

• Dung Beetles: Dung beetles roll dung into balls and push them into the soil. This helps fertilize the soil and keeps the surroundings clean.
• Honeybees: We get honey and wax from honeybees. They also visit various flowers, helping with pollination along with butterflies and moths.
• Praying Mantis: This insect eats harmful bugs like grasshoppers and crickets, which can destroy plants.
• Ladybugs: Ladybugs help gardens by eating pests that suck on plants.
• Silkworms: The silk we use to make clothes comes from the cocoons of silkworms.
• Dragonflies: Dragonfly larvae help by eating mosquito larvae in water, and adult dragonflies eat other flying insects.

Harmful Insects

• Locusts: Locusts can quickly destroy large areas of farmland by eating crops.
• Tree Borer Beetles: These beetles harm trees by burrowing into their trunks.
• Aphids: Aphids harm plants by sucking the sap out of them, which can decrease the amount of crops a plant produces.
• Bed Bugs and Mosquitoes: These insects bite people and drink their blood, which can spread diseases.
• Wasps and Hornets: They can be harmful because they eat beneficial insects like honeybees.
• Termites and Carpenter Ants: These insects damage wooden items like furniture.
• Silverfish, Cockroaches, Moths: These insects can ruin clothing made from materials like silk and wool.

Take a Practice Test Test yourself on topics from Class 3 exam

Practice Now

Practice Now

How Do Insects Help Us?

Insects are our tiny companions. They are incredibly beneficial to us in several ways:

• Insects Control Pests: Many insects eat other harmful insects, keeping their populations under control and protecting our crops.
• Pollination: Insects like bees, butterflies, and moths visit flowers and help in the pollination process, which is essential for the growth of fruits and seeds.
• Soil Health: Insects like earthworms and beetles help improve soil health by breaking down organic matter and aerating the soil.
• Indicators of Environmental Health: The presence and diversity of insects can tell us a lot about the health of our environment.
• Inspiration: Insects amaze us with their intricate behaviors, colors, and the vital roles they play in various ecosystems.