Social behaviour

Question 1

What are the Cost-benefits to living in groups?

Answer 1

Individuals in the group must be better off than alone
Share food, forage further but more likely to find food, less time looking for predators
Maybe short term costs, but longer term benefits
Hunting together (confusion effect - Gannets); co-operative hunting (painted wolves, chimpanzees)
Protection against predation: vigilance / mobbing / confusion effect
Thermoregulation; Conserving energy expenditure

Question 2

What are the costs of group living?

Answer 2

Competition
Disease risk
Risk of being cuckolded
Risk of being cannibalised
Risk of inbreeding (risk of suppressed breeding)

Question 3

How can you describe a group of animals?

Answer 3

By size
Sex ratio
Differentiation in roles
Relationship with individuals within the group
Kinship (familial relationship)

Question 4

What is society characterised by?

Answer 4

division of labour based on a caste system

Question 5

What is a caste system?

Answer 5

Caste “Rigid limited role determined by upbringing”
most group members do not reproduce (sterile)
serve the group by foraging, building, young rearing, and defense
E.g. Honeybees (queen bee and workers), ants, and termites form complex colonies of eusocial individuals

Question 6

Why does “Eusociality” occur?

Answer 6

In eusocial colonies, workers are closely related (3/4 of the same genes) thus, the fitness (chance of passing on genes) is greater in a colony than individual on its own
Fitness is enhanced if these relatives work together

Question 7

So, why do wolves hunt in large social packs?

Answer 7

Catching more prey means that the frequency of being able to eat increases
As a member of a large pack, you may not get as much food, but you will eat more frequently