Cooperation

Question 1

Why is the evolution of cooperation challenging?

Answer 1

• Costly (energy and time)
• Dangerous (decreases survival)
• Better to hang back
• Defection / cheating can easily invade

Question 2

Defectors

Answer 2

Natural selection favours defectors. They have higher payoff (fitness) than cooperators, therefore, natural selection should reduce the abundance of cooperators until they are extinct.

Question 3

Cooperative Breeders

Answer 3

A social system characterized by a dominant breeding pair and subordinate helpers. The helpers provide allocare for offspring of breeders.

Question 4

Types of Social Interaction

Answer 4

Mutualism: both benefit
Selfishness: actor benefits, cost to recipient
Altruism: recipient benefits, cost to actor
Spite: both suffer costs

Question 5

Mutualism

Answer 5

Immediate direct fitness returns for all parties. (There are costs, but everyone gains!)

Question 6

Kin Selection and Cooperation

Answer 6

Natural selection favours cooperation if the donor and the recipient of an altruistic act are related.

Question 7

Direct Benefits of Cooperation

Answer 7

• Reciprocity
• Increased survival (pay to stay, group augmentation)
• Increased reproduction (extra parental experience, territory/mate inheritance)

Question 8

Reciprocity

Answer 8

(AKA reciprocal altruism) Help is repaid in kind by the recipient.
Relies on:
- Repeated encounters between the same two individuals
- Both individuals must be able to help
- Help must be less costly for donor than it is beneficial for the recipient

ie. Regurgitation of blood by vampire bats.

Question 9

Pay-to-Stay

Answer 9

A subordinate individual will be tolerated and maybe protected by dominant individuals, as long as they help them.

Question 10

Extra parental experience

Answer 10

Seychelles Warblers – Birds who had previous breeding experience were better able to fledge young, birds who had just been helpers were also better able to fledge young.
Helping could make you a better parent in the future!

Question 11

Territory / Mate Inheritance

Answer 11

Pied Kingfishers – Colonial nesters. Pairs help raise young, and can have added help at the nests. Many have their sons come back and help them raise young by fishing for siblings (primary helpers). Sometimes, when conditions are bad, secondary non-related helpers may also come into play.

This is costly, but beneficial in the future. Secondary helpers have a high chance of mating in the second year, often with the female they were helping before.

Question 12

Reputational Benefits of Cooperation

Answer 12

(signaling) Helping someone establishes a good reputation, which is rewarded by others. Those who are more helpful are more likely to receive help. Also indicative of cognitive skills.