SOCIAL ANIMALS

Social animals are those in which individuals of the same species live together cooperatively in organized communities known as societies or colonies.

A colony is a group of individuals belonging to the same species and organized in a cooperative manner. Examples of social animals are termites, bees or wasps, ants, wolves, foxes and baboons.

 

Social Insects

Social insects are speicalised group of insects of the same species which live together co-operatively in organized community known as colonies. Popular examples of social insects are termites, bees and ants.

 

Characteristics or Features of Social Insects

1. They live together in colonies.
2. They show or display division of labour.
3. They show distinct castes.
4. Members communicate with one another within the colonies.

 

Termites

Habitat: Termites are usually found living together in large communities in nests which may be tunnels in dead wood, chambers under the ground or anthills (termitaria).

Castes: All the various individuals in a termite colony are grouped into three castes as follows:

• the reproductives.
• the soldiers.
• the workers.

 

A) The reproductives: There are three types of reproductives. These are:

1. king.
2. queen.
3. winged reproductives.

 

1) The King

Features of the King

• The king is a reproductive male individual.
• It has no wing
• It is smaller than the queen.

 

Function: The function of the king is to mate or fertilise the queen.

 

2) The Queen

Features of the Queen

• The queen is a reproductive female individual.
• It has a small head and a small thorax.
• The abdomen is large and swollen with eggs.
• There is only one queen at a time in a colony.
• The queen is the largest of all the castes.

 

Functions: The function of the queen is to lay eggs.

 

3) The Winged Reproductives 

Features of the winged reproductives

• They have wings.
• The are fertile.
• They can reproduce.
• They are potential kings and queens of new colonies.

 

Function: They can become new queens or kings in a new colony after a nuptial or wedding flight.

 

B) Soldiers

Features of Soldiers

1. They are sterile.
2. They do not have wings
3. They have big head equipped with strong maxillae and mandibles.
4. They are blind.
5. There are two types of soldiers. These are the mandibulate soldiers which have strong mandibles for attacking intruders and ten nasute soldiers which have projected mouthparts which can be used to inject poison into any intruder.

 

Function of solders (termites): Soldiers defend the colony against enemies.

 

C) Workers

Feature of Workers

1. They are wingless.
2. They are blind.
3. They are sterile.
4. They form the majority in the colony.
5. They posses well developed mouthparts.

 

Functions of Workers (termites)

1. They build and repair the termite nest.
2. They provide food for members of the colony.
3. They take away the eggs laid by the queen, put them in the chambers and look after them.
4. They look after the nymphs (baby termites).
5. They fed the nymphs and the queen.
6. They cultivate fungus garden, that is, the growth of fungus to digest the wood on which it grows to a state the termite can use. The termite eats both the fungus and partly the digested wood.

 

Life History of the Termite

The termite exhibits incomplete metamorphosis,

i.e, eggs -> nymphs -> adult.

The king fertilises the queen that lays numerous eggs. The workers take care of the eggs till they hatch into young termites called nymphs. The nymphs develop into soldiers or reproductives. The nymphs which fail to develop become the workers.

When the winged reproductives are matured, they swarm out from the existing colony to build new ones. This flight is called the nuptial or wedding flight. After flying for some times, they fall to the ground, lose their wings, pair up, mate and reproduce in a hole they have dug. Inside the hole, the female lays eggs and becomes the queen of the new colony while the male becomes the kings. The laid eggs later hatch into winged reproductives, soldiers and workers.

 

Behavioural Adaptation of Termite for survival

1. The pattern of movement in a group or cluster enable them to ward off their enemies.
2. The ability to feed on dead wood and living plants provide them with a wide variety of diet.
3. Their burrowing activities into the soil or heart of wood or their ability to build tunnels offer them protection against enemies and adverse weather conditions.
4. The selective feeding of nymphs by workers, determines the caste a young one will eventually belong to.
5. Tunnelling or inter-connectivity tunnels provide aeration within the anthill.
6. The habit of feeding on dead members helps to keep the colony clean and healthy.
7. Nuptial or wedding flights lead to the formation of new colonies.
8. Their ability to communicate enhances coordination.
9. Production of many young ones ensure survival.

 

Economic Importance of Termites

1. The clay obtained from anthill is used to build the surface of tennis court.
2. Termites help in loosening and aerating the soil through the tunnels they build.
3. Termites destroy wood and furniture by their feeding habits.
4. They produce a good source of protein and fats.
5. Their activities during the breaking down of wood help to add humus in the soil.

 

Honey Bees

Habitat: Honey bees are also social insects that live in large communities in hives which is made up of chambers. Each chamber is called a cell.

 

Castes of Honey Bees

There are three castes in a bee colony. These castes are

• drone.
• queen.
• worker.

 

A) Drone of the Honey Bee

Features of the Drone

1. The drone has wings.
2. It is the male.
3. The abdomen is shorter than that of the queen.
4. It is bigger than the workers.

 

Function: One drone mates with the queen during the nuptial flight after which the drone dies.

 

B) Queen of the Honey Bee

Features of the Queen

1. The queen has wings.
2. It is a fertile female.
3. It is attended to by workers.
4. It is much bigger than the workers.
5. It is fed with royal jelly.

 

Function: The queen lays eggs.

 

C) Workers of Honey Bee

Features of the workers

1. It is smaller than the queen or drone.
2. It is a sterile female.
3. It possesses eyes and a sting.
4. It has modified mouthparts used for collecting nectar and for building the hive.
5. The legs are also modified for collecting pollen grains from flowers.

 

The functions of the worker change with age. For example, while a young worker bee performs household chores, the adult workers bee forages for food outside.

The functions of workers are:

1. They clean the cells.
2. They feed older larvae with honey.
3. They clean the nest.
4. They ventilate the hive.
5. They secrete wax and build the hive with it.
6. They collect pollen and nectar.
7. They guard the hive.
8. They process honey and pollen.
9. They feed the larvae with royal jelly.

As soon as a worker bee locates a food source, it performs a special dance called ‘tail waggling‘ dance which indicates to other workers the direction and distance of the food source.

 

Economic Importance of Honey bees

Honey bees perform two beneficial roles to man.

These are:

1. They help to pollinate flowers.
2. They are source of honey.