Insects are the largest group of animals on earth. They constitute about 80% of the animal population.
They are robust in living and are widely distributed in the environment.
Man has conquered every other animal except these insects.
Some of the insects are useful to man, while few of them are harmful.
But most of them are neutral and involved in the natural ecosystem. They serve the purpose of pollination, act as food to birds and other animals.
Insects are of different types, and we may confuse with worms. We can classify them based o their morphology, habitats, and other characters.
A typical insect has 6 legs (appendages) and wings to fly. But insects differ from each other based on a few characters.
Types of insects
1. Based on food habits
a. Carnivorous insects: These insects rely on other animal tissue to feed on. They do not cherish a vegetarian diet. Ex: Housefly, the mosquito.
b. Herbivorous insects: They live exclusively on plant material like flower nectar, seeds, leaves, etc. Butterfly, dragonfly.
2. Classification based on presence of wings:
a. Wingless insects: These insects lack wings in their entire life cycle. Ex: Apterygota, Scorpion, spiders, etc.
b. Winged insects: These insects have wings. They are called true insects. In general, most insects have wings like butterflies, house fly, etc.
3. Types of insects based on the method of Living
a. Free-living: These insects search for their own food. They mostly consume dead material or plant material. Ex: cockroaches.
Ex: Head louse, bed mites, etc.
4. Types based on the living habitat:
Insects differ in their place of abode. Few live on trees, while others on land and some of them on water or in water. Based on this, we have aquatic and terrestrial insects.
a. Aquatic insects: These insects live on the water. They can even dive into the depths of water and hunt the prey. They have special organs ad methods of respiration. They have gills, respiratory tubes, etc.
b. Terrestrial insects: These are the insects that survive only on land. They may even make holes and deep dwellings inside the earth for survival. Ex: Ants, cockroaches, etc.
Based on social behavior: Insects though being very tiny, have good communication among themselves. Most of the insects live alone, i.e., on their own. But some of them live in groups or colonies. So based on this socializing behavior, we can classify them as
Individual/reclusive: These insects live individually and not in groups. They satisfy their own needs and do not support others. Ex: Housefly, mosquito, etc.
Social insects: These insects live in groups or colonies in a burrow or beehive. They share their work and
also responsibilities towards the colony. They search for food and together work to collect and accumulate food. They even form specific directions or paths to collect food, as seen in ants and honey bees. They communicate with each other regarding the availability and direction of food.
There is a queen ant with the ability to fly. Male sterile ants also with the ability to fly, and sterile female ants which act as workers. Female queen ant lays eggs. The worker ants or bees work to save, nourish, and protect the queen and offspring. Even there will be fights between colonies, and large worker ants die to save their colony.
Reptiles like snakes try to invade their ant-hill (formicary) for shelter. In such cases, ants attack them and may even kill them to save their nest.