SOCIAL BEHAVIOUR:

Social behavior is defined as interactions among individuals, normally

within the same species, that are usually beneficial to one or more of the
individuals.

Social behavior evolved because it was beneficial to those who engaged

in it, which means that these individuals were more likely to survive and
reproduce.

Social behavior serves many purposes and is exhibited by an

extraordinary wide variety of animals, including invertebrates, fish, birds,
and mammals. Thus, social behavior is not only displayed by animals
possessing well-developed brains and nervous systems.

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BENEFITS OF SOCIAL BEHAVIOR:

Social behavior seems to provide many benefits to those who practice

it.

1. Many animals are more successful in finding food if they search as a

group.

2. If more individuals are cooperating in the search, there is a greater chance

one of them will find the clump of food.

3. In some cases, foraging in a group makes it easier to capture a prey.

4. Dolphins are known to surround a school of fish and to take turns darting
into the center to eat the fish that are trapped in the middle.

5. Many carnivores will band together when they try to capture large prey.
For examples, wolves will hunt together when hunting moose, and lions
will hunt together when hunting large prey such as wildebeests.
6. Many animals live in social groups partly for protection.

7. Some animals form social groups to make travel easier.

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SOCIAL BEHAVIOUR IN INSECTS:

Social Organization is most developed in insects. Insects are eusocial (i.e.,

have true societies) and their eusociality is exhibited in terms of their following
attributes:

1. COOPERATION: Members of same species show great cooperation.

2. DIVISION OF LABOR: There is distinct division of labor in some

colonial insects. A group of individuals of the same colony become only
workers and others only reproduce.

3. OVERLAPPING OF GENERATIONS: At any stage, at least two

generations overlap in a colony of insects.

Social Behaviour in Insects refers to the complex and coordinated interactions

among members of the same species, often leading to the formation of organized
communities or colonies. This behavior is particularly well-developed in a group of
insects known as eusocial insects, which include ants, bees, wasps, and termites.

Here’s an overview of key aspects of social behavior in insects:

1. Eusociality

Eusociality is the highest level of social organization and is characterized by:

 Cooperative brood care (individuals care for offspring that are not their own)
 Reproductive division of labor (castes: queens, workers, and sometimes
soldiers)

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  Overlapping generations (parents and offspring live together)

2. Caste System

Most social insects have a caste system:

 Queen – the reproductive female.

 Workers – sterile females who perform tasks like foraging, cleaning, and
nursing.
 Drones (in bees) – males whose main role is mating.
 Soldiers (in some ants and termites) – specialized for defense.

3. Nest Building

Social insects construct intricate nests or hives:

 Termites build mounds with ventilation systems.

 Bees make wax hives.
 Ants build underground colonies with complex tunnels.

4. Communication

Communication is essential for colony function:

 Pheromones – chemical signals used to mark trails, signal danger, or regulate

reproduction.
 Tactile signals – like antennae tapping.
 Auditory signals – e.g., termites use vibrations.
 Dance language – honeybees use the waggle dance to indicate food source
location.

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5. Division of Labor

Tasks are divided based on caste, age, or need:

 Foraging, caring for young, nest maintenance, and defense are distributed
among individuals

6. Altruism and Kin Selection

Many behaviors seem altruistic (e.g., sterile workers caring for the queen’s
offspring), but they can be explained by kin selection – promoting the survival of
shared genes.

7. Colony Life Cycle

Colonies go through stages:

 Founding – a queen starts a new colony.

 Growth – workers take over duties.
 Reproduction – the colony produces new queens and males.
 Dispersal – reproductive individuals leave to form new colonies.

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INSECT SOCIETY:

A social insect has unique features. Although an insect society has thousands
of members, but they all constitute one family. Majority of the members are
busy in activities that will end into the production of more individuals by the
queen. These individuals are moulded into different casts by the "feeding
action". Insect societies are termed eusocial for the following reasons:

1. They are essentially permanent.

2. They show mutual cooperation among inmates.

3. They contain offspring usually produced by a single female called as

queen.

4. They exhibit the overlapping of generations; queen survives over her

offspring generations.

5. They include members which are so attached to one another that their
existence depends upon the survival of entire colony.

These features are followed by only two groups of insects namely:

1. Order Isoptera: Ex: Termites

2. Order Hymenoptera: Ex: Honey bees, wasps and ants.

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INSECT SOCIETY: An Overview

Insect societies are some of the most complex and organized systems found in
nature. They’re especially prominent in species like ants, bees, wasps, and termites—
collectively known as eusocial insects.

Key Features of Insect Societies:

1. Division of Labor
o Roles are often divided among castes: queens, workers, drones/soldiers.
o Workers handle foraging, nursing, defending the colony, etc.
2. Cooperative Brood Care
o Members care for offspring that aren't their own.
3. Overlapping Generations
o Multiple generations live together, allowing older individuals to help
rear the young.
4. Communication Systems
o Pheromones, vibrations, and dances (like the honeybee’s waggle dance)
are used to coordinate activity.
5. Colony Organization
o Colonies can function like a single "superorganism"—individuals
sacrifice their own reproductive opportunities for the good of the group.

Examples:

 Ant Colonies: Massive underground networks with specialized roles.

 Bee Hives: Complex wax structures with a queen, drones, and workers.
 Termite Mounds: Architecturally intricate with climate control systems.

Evolutionary Benefit:

Eusocial behavior increases the survival rate of the colony as a whole, even if
individual members sacrifice their own direct reproductive success.

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 I. SOCIAL ORGANISATION IN HONEY BEES:

The social organization of the honey-bees is established by the living of all

individuals within the colony and they show the mutual cooperation among the
members of the colony, and exhibit the overlapping generations.

At least there is a division of labour among the different types of honey-bees

in the colony or hive. The different forms or types of insects having a
particular function live in the colony, called the castes.

CASTE SYSTEM:

Thousands of bees (50,000 to 1,00,000 or more) which live in a hive are of three
different forms:

(1) Workers (infertile females)

(2) Drones (males)

(3) Queens (fertile females)

The phenomenon of existence of several morphological forms with

separate functions in a species is known as polymorphism. So, honey-bees are
well known as social and polymorphic insects.

Both queen and workers are female and diploid. Drones are males and
haploid. A strong or healthy colony is called when the maximum number of
workers is found in the colony.

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The social organization in honey bees is a classic example of eusociality, one of the
most complex forms of animal social structure. Here's an overview of how honey bee
society is organized:

I. SOCIAL ORGANIZATION IN HONEY BEES

Honey bees (genus Apis) live in well-structured colonies that display a high level of
organization and division of labor. Each colony functions like a superorganism, with
different members performing specific roles for the survival and efficiency of the
whole.

1. Caste System

The bee society is divided into three main castes:

 Queen Bee
o Only one queen per hive.
o Sole fertile female responsible for laying eggs (up to 2,000 per day).
o Develops from a fertilized egg but is fed royal jelly throughout her
development.
o Releases pheromones to maintain social harmony and suppress worker
fertility.
 Worker Bees
o Infertile females, making up the majority of the hive population.
o Perform all tasks needed to maintain the colony:
 Nursing larvae
 Cleaning cells
 Foraging for nectar and pollen
 Producing honey and wax
 Guarding the hive
o Roles change with age (age polyethism).

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  Drone Bees
o Male bees whose sole role is to mate with a virgin queen.
o Arise from unfertilized eggs (haploid).
o Do not collect food or perform any work in the hive.
o Die shortly after mating or are expelled from the hive in winter.

2. Division of Labor (Age Polyethism in Workers)

Worker bees take on different roles as they age:

Age (Days) Role

1–3 Cell cleaning
3–10 Feeding larvae (nurse)
10–16 Wax production, building
16–20 Guarding the hive
20+ Foraging (nectar/pollen)

3. Communication

 Waggle Dance: Forager bees perform this dance to communicate the direction
and distance of food sources.
 Pheromones: Used extensively to signal alarm, mating readiness, queen
presence, and hive cohesion.

4. Nest and Hive Structure

 Constructed from wax secreted by worker bees.

 Includes:
o Brood cells (for larvae and pupae)
o Honey cells (for food storage)
o Drone and queen cells (for reproduction)

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5. Reproduction and Swarming

 Swarming is the natural method of colony reproduction.

 The old queen leaves with part of the colony to form a new hive.

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QUEEN BEE:

Generally, a single matured queen is present in each hive. The size of the
queen is nearly 2.5 times longer than that of a worker bee. It is characterized by
the long tapering abdomen, well-proportioned body, short and golden coloured
wings and colour of the legs. They are 2.8 times heavier than the worker bees.

• The function of the queen is reproduction and lays about 1000- 2000 eggs
every day depending upon seasonal variation and seasonal factors.

• The eggs may be either fertilized or unfertilized.

• Depending on the type of food supplied to the newly developed larvae by

the nursing workers the eggs may develop either queen or workers.

• The drones or males are produced by the laying of unfertilized eggs (i.e.
parthenogenetically).

• The queen deposits each egg in a cell prepared by the worker bees. After
three days the eggs hatch into small larvae.

• The larva which is fed with a special food called ‘royal jelly’ develops
into queen.

• The royal jelly is a high protein substance produced by the

hypopharyngeal glands of the workers.

• The larva which is selected to become queen is taken before the third day
of development in a special chamber, called queen’s chamber.

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• The queen lives five to eight years on average and her fertility decreases
with the increase of age.

• The queen secretes a kind of chemical substance with hormonal

properties from the mandibular glands, called pheromone or queen
substance which inhibits the growth of ovaries of workers and
control the activities of all bees within the hive.

• She can attract the workers towards the queen and stimulates the workers
to build wax cells for worker bees and drones but prevents in the building
of queen cells.

• When the queen becomes matured, she leaves the hive with some drones
and takes several nuptial flights and mates with a drone.

• The queen after copulation returns in her old hive and is looked after by
nurse workers, known as her retinue.

• With the increase of the age, the egg laying capacity of the queen loses,
the workers choose a three-day old egg. This egg after hatching into larva
is fed with royal jelly and it develops a new queen in about 16 days. At
that time the old queen leaves the hive along with some workers to
establish a new colony.

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DRONES:

• The drones are the male members of the bee colony and are haploid each
genetically.

• The drones take 24 days to develop from the egg to adult.

• They have no food (pollen and nectar) collecting organs.

• So, the drones are totally dependent on worker bees for food.

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 • The main function is to fertilize the queens.

WORKERS:

• The size of worker bee is small but they constitute the majority in a hive.

• They are produced by the fertilized eggs laid by the queen.

• It takes 20 days from egg to adult and life span is about 6 weeks.

Functions of workers:

• All the time in their lives is spent for the maintenance of the hives and
caring for their members.

• Workers are involved in hive construction, clean the cells of the hives
collect the nectar, pollen and water and store within the cell properly.

• They repair the cracks in the walls of the comb.

• The workers also maintain the optimum temperature within the hive by
fanning during summer.

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NUPTIAL FLIGHT AND COPULATION:

• About a week after emergence from her chamber, the new queen flies in
air with many drones.

• The copulation takes place in the air with a drone and the queen receives
the spermatophores from the drone.

• After copulation, the drone dies immediately.

• The flight of one queen with several drones in air for copulation is called
nuptial flight.

Nuptial Flight and Copulation

Nuptial flight is a mating behavior observed in many social insects, especially ants,
termites, and bees. It involves reproductive individuals (often called alates — winged
males and females) leaving their colonies to mate in the air.

Nuptial Flight:

 Timing: Often triggered by environmental cues like temperature, humidity,

and time of year (e.g., after rain).
 Purpose: To allow genetic mixing between colonies and the establishment of
new colonies.
 Process:
o Winged males and virgin queens swarm out of their nests.
o They gather in the air in large numbers, sometimes across species.
o Mating occurs mid-air or shortly after landing.

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Copulation:

 Mating Behavior:
o Males typically die soon after mating.
o Queens store the sperm in a specialized organ called the spermatheca
for use over their lifetime.
 Post-Copulation:
o Females shed their wings.
o Fertilized queens seek a suitable place to start a new colony.
o She uses stored sperm to fertilize eggs for years, sometimes decades.

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HIVE OR COMB:

The worker bees construct hive with the help of wax secreted from the wax
secreting glands of the abdomen. There are 5 types of cells in the hive. They are;
1. Queen cells: These are a very few in number in a hive. They are larger
than the other cells and vase-shaped, and are situated at the margin of the
comb. These cells are used for queen rearing.

2. Drone cells: There are about 200 drone cells in each hive and are smaller
than the queen cells. The drones are reared in these cells.

3. Worker cells: Majority number of cells is worker cells and each cell is
about 5 mm across. The workers are reared in these cells.

4. Brood cells: The larvae of the honey bee are reared in these cells.

5. Storage cells: These cells are meant for the storage of honey and pollen.

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 AI. SOCIAL ORGANISATION IN TERMITES:

The Termites are commonly known as white ants. They belong to Class-
Insecta, Order- Isoptera and are widely distributed in tropical, subtropical and
temperate regions of the world. These are small, hemimetabolous, soft bodied,
cellulose eating, nocturnal, social and polymorphic insects having two pairs
of similar wings. Ecologically, termites are good decomposers of dead wood
and vegetable products and aid in agriculture by enriching the soil with their
faecal matter and by making the soil permeable to air and moisture, like
earthworms.

These are very significant pests damaging wooden structures. They live
together in very large colonies or communities. There are more than 1,700
species of termites and a few hundreds to as many as 70 lakhs individuals
of same species form a colony. The colonies are matriarch. A colony’s
population is initiated and maintained by a queen that may live for as many as
50 years in some species. All members of a colony are the offspring of a single
female and hence all have similar genotype. The colony reaches its maximum
size in approximately 4 to 5 years.

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COLONY STRUCTURE AND POLYMORPHISM IN TERMITES:

A termite community includes two forms:

(i) Reproductive form or Fertile Caste,

(ii)Sterile form or Caste.

1) REPRODUCTIVE OR FERTILE CASTES:

There are three types of reproductive castes which are fertile males and females.
These are as follows:

a) MACROPTEROUS FORMS OR WINGED FORMS OR FIRST

REPRODUCTIVE CASTE:

These are sexually perfect males and females. They are ancestors of the
community from which other forms have been derived.

• They have two pairs of large, equal-sized wings which project beyond the
abdomen at rest.

• Body is chitinised and dark brown.

• Compound eyes are well developed and there is a pair of ocelli.

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 • Brain and sex organs are larger than in others.

• Males and females leave the nest at maturity, lead a brief aerial life, shed
their wings at the basal sutures, then they come together in pairs and mate.

• After that they find a proper place for a new nest. Each pair is a dealated
King and Queen or Primary Royal Pair.

• They have stumps of shed wings and they are monogamous. The king
and queen are permanently associated.

• The queen becomes large by growth of its abdomen.

• The head and thorax resemble a normal termite but her abdomen is
hugely distended, bulbous, long and white.

• She produces up to 2,000 eggs per day. A royal couple can live up to 50
years in some species.

b) BRACHYPTEROUS FORMS OR SHORT WINGED FORMS OR

SECOND REPRODUCTIVE CASTE:

These are sexually mature males and females but they are nymphal in
appearance.

• Body is less chitinised, pale coloured and have short wing buds only.

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 • The brain and sex organs are smaller in size and compound eyes are not
dark.

• They do not leave the nest.

• If the primary king or queen dies, its place is taken by brachypterous

individuals forming several substitute or complemental king or queen,
which are polygamous.

• Such queens produce fewer eggs.

c) APTEROUS OR WINGLESS FORMS OR THIRD REPRODUCTIVE

CASTE:

These are rare, found in lower termites only.

• They have both males and females.

• These look like nymphal workers.

• They have no wings, cuticle is colourless, compound eyes are vestigial

and ocelli are absent.

• They are known as Ergatoid Kings and Queens.

• They may be several in the colony.

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 2) STERILE FORMS OR CASTES:

There are two types of wingless (apterous) , sterile castes. These are male and
females in which sex organs are rudimentary and non- functional. These are of
two types:

a) STERILE WORKERS:

• These are the smallest in size, look like nymphs, their body is pale
coloured and their integument is less chitinised.

• Compound eyes and ocelli are absent and the head is wide, pointing
downwards.

• The number of workers in a community is very large, about 60,000 to

2,00,000.

• They mature within a year and live from 3 to 5 years.

• With the exception of reproduction and defence, they perform all the
duties of the colony.

• Their main duties are looking after the eggs and the young, finding food,
planting and cultivating fungi, making nests and feeding the queen and
soldiers.

• They also lick and groom each other.

• They have gnawing habit.

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 • The workers destroy crops, wood and human belongings and cause
tremendous loss to man.

• They are xylophagous, feeding on wood.

• They can digest cellulose with the help of intestinal symbiotic flagellates

–Trichonympha, which are passed on from generation to generation.

b) STERILE SOLDIERS:

• These are apterous males and females with no sex organs.

• They are less numerous in the colony than workers.

• A soldier has a large, dark coloured, chitinous head and big mandibles.

• The colour of the body is pale.

• They must be fed by the workers because they cannot feed themselves.

Soldiers are of two types:

(i) Mandibulate soldiers – have large powerful mandibles but no frontal

rostrum.

(ii) Nasute soldiers – have small mandibles and median frontal rostrum on the
head.

• They defend the community.

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 • The mandibulate soldiers with their mandibles and nasute soldiers by
exuding a viscid repellent fluid through the frontal rostrum.

• At times they plug the opening of the burrow with their heads.

TERMITE NEST OR TERMITARIUM:

• The worker termites construct elaborate nests, the termitaria, for

protection, storage of food and maintenance of broods.

• The termite nests vary from simple cavities in soil or wood to vast
subterranean complex or elaborate structures that project well above the
ground, known as mounds.

• The mounds can be up to 6 meters high and are made of excavated mud
wood and excreta mixed with saliva.

• Their walls become hard as rocks.

• The mounds and termitaria have a maze of passages, chambers and

special cells for storing food or cultivating fungus gardens.

• There are special chambers for the royal couple.

• The termitaria are provided with very elaborate ventilation system and
design that provides for maintenance of constant temperature, canopies
that deflect rainwater and other structural adaptations. Termites are best
known nest building insects.

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OTHER CHARACTERISTICS OF TERMITES:

Various castes of termites work in cooperation and with mutual benefit and live
in an integrated manner in the colony. Parental care is well marked in termites –

• The eggs and nymphs develop in fungal chambers or nurseries.

• The queen is fed by workers on saliva and fungal hyphae .

• The workers tend and feed the nymphs on fungus and vegetable matter
which are partly pre-digested by the workers. Thus, symbiotic flagellates
are transferred to nymphs by trophallaxis.

• For progressive provisioning of food for the king, queen and nymphs,
some worker termites cultivate fungus gardens in chambers located near
the centre of the nest.

• These are made of a reddish brown, spongy comb produced by the

workers from vegetable matter and excreta. On the comb fungal hyphae
grow producing white patches.

• Exchange of food between one insect and the other takes place by
mouth- Trophallaxis.

Physical Characteristics

 Soft-bodied and usually pale in color (white to light brown).

 Straight antennae (unlike ants, which have elbowed antennae).


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 

 Wings (in reproductive forms): Two pairs of equal-sized wings during the
swarming stage.
 Mandibles (jaws): Used for chewing wood and other plant material.

Behavioral Characteristics

 Social insects: Live in colonies with a caste system (workers, soldiers,

reproductives).
 Cooperation: Work together to build nests, care for young, and forage for
food.
 Communication: Use pheromones and vibrations to relay information.

Feeding Habits

 Primarily feed on cellulose, found in wood, paper, plants, etc.

 Rely on gut symbionts (protozoa or bacteria) to digest cellulose.

Environmental Preferences

 Prefer moist, dark environments.

 Sensitive to light and dry air—most species build underground or hidden
nests.
 Some species build mud tubes to travel safely in open areas.

Nest Building

 Some species build mounds, others live in wood or underground.

 Nests are climate-controlled and can house thousands to millions of
individuals.

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Reproductive Traits

 A colony starts with a king and queen (primary reproductives).

 Swarming occurs during warm, humid seasons for reproduction.
 Capable of asexual reproduction in some species (queen cloning herself).

Defense Mechanisms

 Soldier termites defend the colony using strong mandibles or chemical

sprays.
 Some can block tunnels with their heads or excrete sticky substances.

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COMMUNICATION IN TERMITES:

• Termites communicate primarily by secreting chemicals called

pheromones or ectohormones.

• Each colony develops its own characteristic odour.

• An intruder is instantly recognized and an alarm pheromone is secreted

that triggers the soldiers to attack.

• If a worker finds a new source of food, it lays a chemical trail for others
to follow.

• The proportion of termites in each caste within the colony is also

regulated chemically.

• Nymphs or immatures can develop into workers, soldiers or reproductive

adults depending on colony needs.

• Sound is other means of communication.

• The Soldiers and workers may bang their heads against the tunnel
creating vibrations perceived by others in the colony and serving to
mobilize the colony to defend itself.

• Mutual exchange of foods enhances recognition of the members.

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1. Chemical Communication (Pheromones)

This is the most important and widely used form of communication in termites.

 Pheromones are chemical signals secreted by termites to influence the

behavior or physiology of others.
 Different types of pheromones include:
o Trail pheromones: Used by foragers to mark paths to food sources.
o Alarm pheromones: Released to alert colony members of danger.
o Reproductive pheromones: Regulate the roles of individuals and inhibit
the development of additional reproductive members.
o Nestmate recognition pheromones: Help termites distinguish colony
members from outsiders.

2. Tactile Communication

Termites also use physical contact to communicate.

 Antennal tapping: Termites touch each other with their antennae to recognize
caste and status.
 Head-butting or drumming: Soldier termites often bang their heads against
tunnel walls to create vibrations that warn the colony of danger.

3. Vibrational Communication

 Termites can send vibrational signals through the substrate (like wood or soil).
 These signals are typically used for:
o Alarm signals
o Caste recognition
o Coordinated construction work

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4. Visual Communication

 Limited due to termites mostly living in dark environments like underground

or inside wood.
 Some reproductive termites (alates) use light cues to fly during mating swarms,
but beyond that, vision plays a minor role.

Summary

Method Purpose
Chemical (pheromones) Trail marking, caste regulation, alarm
Tactile Recognition, coordination
Vibrational Alarm, construction, colony coordination
Visual Limited use, mainly during reproduction

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 SOCIAL SYSTEM IN PRIMATES:

Sociality is very common among mammals. It predominantly occurs in deer,

wolf, cattle, sheep, horse and primates. Of these, primates (Monkeys and Apes)
show an elaborate social life. Primates show marked socialization.

The sociality of primates has been enhanced by the following attributes:

1. enlargement of brain,

2. development of grasping hand,

3. great reliance on vision for exploration and communication and

4. diversity in their arboreal and terrestrial habitats.

TYPES OF SOCIAL BEHAVIOUR IN PRIMATES:

There are 6 different groups under which the social organisation in apes and
monkeys can be studied. They are:

1) Solitary type.

2) Monogamous type.

3) Unimale bisexual group or Single male with bonded females and

offsprings type.

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 4) Aggregate single male group with bonded females and offsprings type.

5) Multimale bisexual groups.

6) Diffuse social parties.

i. SOLITARY TYPE:

• Examples. Orangutan (ape), aye-aye (ape), loris (tree monkey), etc.

• This is a type of social behaviour where the primates (monkey and apes)
tend to sped their entire life in a confined area. These do not leave their
home range and spend almost isolated life.

• Orangutans lead an almost totally solitary life.

• They associate only for mating and an offspring is dependent on its

mother.

• They are entirely arboreal and both sexes tend to stay in a home range
over which they travel throughout the year following the fruiting of trees.

ii. MONOGAMOUS TYPE:

• Examples. Gibbons, tree shrews, lemurs, marmosets etc.

• Monogamy is very rare.

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• However, it is perfectly exemplified by the gibbons whose life long pair
bond between a male and female and their strict territoriality, maintained
by elaborate singing especially at dawn, show remarkable parallels to
some birds.

• Gibbons are found in South America.

• Their groups include 4-8 individuals constituting an adult male and adult
female and up to 4 young ones.

• There is not much difference in body size of male and female.

• There exists equal dominance between males and females.

• Both of them (male and female) involve themselves in all activities with
same intensity.

• South American marmosets and tamarins, also have very small groups
with often one, or at the most three adults of each sex in the group
together with their young.

• Almost all other primates give birth to single offspring, but marmosets
always have twins and males help with the care of infants, carrying them
for much of the time.

• Monogamous primates are usually smaller in size; they feed on high

protein diet, viz. insects, new leaves and ripe fruits.

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• The parental investment is equal, the female feeds the young and male
carries young on his back.

• Antipredator device involves concealment.

iii. SINGLE MALE GROUPS WITH BONDED FEMALES AND

OFFSPRINGS (UNIMALE BISEXUAL GROUPS):

• Examples: Patas monkey, hanuman langurs, red howler monkey,

redd tail monkey, blue monkey, etc.

• These primates typically live in unimale bisexual groups; their group may
have 20 to 100 individuals, there will be just one adult; fully grown,
big-sized, agile dominant male which is called overlord or resident
male.

• Rest of the group is formed by adult females, subadult females, male and
female juveniles, and infants.

• Adult male is the leader and coordinator of group activity.

• He initiates and determines the direction of group movement and

activities such as where to go, when to feed, where to sleep, etc.

• Thus, in male bisexual groups or hanuman langur it is usually the

adult male who alone defends the territory.

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• He herds females away from intruding males of all male groups.
Generally, he alone indulges in fights. Very seldom females may also
participate in the fights.

• The overlord (male) is much larger than females and is dominant over all
the members of his group and there is no dominance hierarchy among
females is dominant

• Male parent investment is almost nil.

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AGGREGATE SINGLE MALE GROUP WITH BONDED FEMALES
AND

OFFSPRINGS:

iii. Examples. Baboons.

iv. The baboons are large sized primates found in Ethiopia and Somalia;
the males have heavy mane around neck and have dog-like muzzle.

v. In their social organisation several females are more or less

permanently bonded to a single male forming a so-called "harem
group".

vi. A number of such groups band together, moving and foraging as a

unit, perhaps 40 to 50 strong baboons.

vii. Thus, baboons form large troops on cliffs to sleep together.

viii. The troops separate into bands before travelling to foraging areas
each morning; bands fragment into one male unit while foraging and
then reunite into bands to travel back to the cliff in evenings and
nights to sleep together as a large multiple-bisexual group.

ix. Adult males form temporary consort ship (separate from the group)
with females as they enter reproductive phase. Otherwise move
generally within the group.

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 MULTIMALE BISEXUAL GROUPS:

• Examples: Rhesus monkey, gorilla, spider monkey, squirrel

monkey, etc.

• Typically, there are 3-8 adult males in a group, each of which has
bonded females who remain with their infants.

• In a way, there are many small units living together thus forming a big
group (sometime up to 180 or more individuals).

Sometimes there are following two major types of individuals within multimale
bisexual grouping:

1. Those which do not divide in smaller feeding groups, e.g., gorillas.

2. Those which divide daily into smaller feeding groups, e.g., rhesus
monkeys.

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IN GORILLAS:

• the group is typically a multimale bisexual type with several males and
sever females, all the members remain together.

• The males have dominance hierarchy.

• The most dominant is called alpha, then beta, gamma and so on.

• There is a simple linear dominance hierarchy among the adult males of a

troop.

• But there is no clear-cut dominance system among females.

• In a typical group of gorillas of 20 individuals, the oldest and or largest

male, develops grey hair on his back and is called silver back.

• He is also most dominant; rest of the males would be lower in status.

• Dominance consists of possession of right to the way on narrow path, or

to a resting place or feeding site.

• Surprisingly, in contrast to all other primates, dominant males in gorilla

are not very aggressive and all other males also have access to receptive
females.

• There is no conflict for the females

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RHESUS MONKEY:

• It is widely distributed in India and lives in large multimale bisexual

groups.

• The males have dominance hierarchy and in them, the bonded

females acquire dominance from the males they have been affiliated
or bonded with. For example, if the alpha is most dominant male, his
bonded females will enjoy high place in dominance hierarchy among
females and rest of group members, even their infants acquire that
dominance.

• The dominant males can be identified easily by their confident walk and
by their long strides, they carry their tails up and a subordinate male
walks carefully and tucks its tail between the hind limbs.

• If the alpha male goes away from the group for a short while the beta
male raises its tail and as soon as the alpha returns it again takes the tail
down.

• The group may split temporarily into family units for foraging. All family
units remain near vicinity and can unite at the time of danger, for day
resting and every evening for roosting.

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 vi. DIFFUSE SOCIAL PARTIES.

• Examples. Chimpanzee.

• The chimpanzees represent the living apes, the closest relative of

humans.

• Chimpanzees share about 99 per cent of their genetic material with

humans.

• Chimpanzees are expert climbers, rest in sitting posture and walk on

hind limbs but run on all four limbs.

• Chimps usually live-in groups.

• Males guard territory and restrict entry of males from other groups.

• The whole community searches food but breaks into smaller parties in
case when food availability is less, group size of chimpanzees is thus
proportional to the food availability.

• Furthermore, in small groups (n =3 to 6), each member has

responsibility of searching its own food.
•

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SPECIAL FEATURES OF PRIMATE SOCIALIZATION:

1. Primate groupings are close associations of conspecifics residing in a

territorial limit.

2. Each member has access to all kinds of information relating to food,

water and danger, within the group and also to activities of neighbours.
3. Group size may vary from two to hundreds of members.

4. Clustering is always avoided and optimum group size matches perfectly

to the amount of food and also furnishes adequate sleeping site.
5. The social grouping is based on the basis of rank relations, alliances and
rivalries.

6. A close tie exists between near-relatives and loose bonds are found
between nucleus and peripheral individuals. This type of social
organisation is exemplified by the monkeys.

7. Reproduction is all year phenomenon and young-ones have close

relations with male and females of all ages, until they are mature
themselves to play distinct ecological and adult roles.

8. The group composition is adapted to life in a certain environment.

9. Primate societies lacks blind following. Instead, all members

communicate with each other through sounds and gestures and also by
watching the behaviours of others in the group.

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10.Each individual is constantly responsive to the posture, movements,
gestures.

11.Primates’ social organization is meant for constant exploration during

daily walks on the basis of memory for the life purposes.

12.Primate societies have distinct division of labour and rank ordering.

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ADVANTAGES OF SOCIAL ORGANIZATION:

1) A permanent social structure is maintained.

2) A complex communication within the group is established which could

be easily understood among the members of group.

3) Specialization based on division of labour is seen in order to maintain

confusion about work distribution.

4) Strict cohesion among the members is seen where each member in the
group defends for other and fight if needed.
5) Impermeability to conspecifics.

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