Behavioural Ecology 1

Question 1

What is classical game theory, and what is evolutionary game theory?

Answer 1

Game theory approach:

‘Classical’ game theory (economics) -
assumes contestants can choose from a defined set of ‘strategies.’

The overall plan of action for the contest the deer fights strategy - roar, parallel walk, then antler wrestle.

Tactics- Rate of roaring, how hard to push

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‘Evolutionary’ game theory- Which strategy natural selection should choose, work out if a non-injurious strategy.

-most likely outcome of selection acting on individuals.

• The best thing to do depends on what the opponent does.

-the benefit is frequency dependent (dependent on how many other individuals in the population doing that thing and influences how often it will be encountered)

Question 2

What are the 3 steps to game theory/analysing fighting games

Answer 2

1. Specify the alternative strategies
2. Specify the pay-off of each alternative
3. Find expected solution

Question 3

Explain the Dove/Hawk Game

Answer 3

Hawk vs Hawk- 50% chance of winning, 50% chance of injury

Hawk vs Dove- Hawk always wins, and Dove always runs away.

Dove vs Hawk- No Injury, but Dove doesn’t win, just runs away.

Dove vs Dove- No Injury, 50% chance of winning

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What are the pay-offs?

Hawk fighting dove- dove runs away, so hawk always wins the value of the resource.

Dove fighting hawk- 0 pay off as dove will not get resources.

Dove fighting Dove- Don’t get injured, win half the time, and on average, win half the value of the resource.

Hawk fighting hawk- will win Value of resource half the time, but also half the time Cost of injury as will lose half the fights. The Hawks only retreat when injured.

Solution=

ESS- Evolutionary Stable Strategy

-Hawk would be expected Natural selection to produce.

Question 4

What is the assessor strategy?

Answer 4

Assesses opponents RHP

Play Hawk if stronger than the opponent and Dove if weaker.

Question 5

Using real examples and relevant theory, explain why animals rarely fight to the death.

Answer 5

Use of Signalling
-Save time and energy and reduce the potential for injury

When thinking of Dove and Hawk and Assessor theory, animals would assess other individuals to either analyse their strategy or assess to see if they are stronger or weaker than opponent. Usually, in the case where C> V (Cost is higher than value of resource.)

Hawk- dove game shows that the evolution of non-injurious fighting is expected in the case of natural selection where C>V.

Fighting is highly costly, so more beneficial for individuals to use forms of communication to either scare off competition or avoid fighting altogether; in example of red deer, there are steps before fighting occurs; this helps communicate the stronger individual before fighting.

Answer 6

Starling murmuration is an aerial stunt that birds perform.

• Grouping together offers safety in numbers
  – predators such as peregrine falcons find it hard to target one bird in the middle of a hypnotising flock of thousands.
  -They also gather to keep warm at night and to exchange information, such as good feeding areas.
  -They gather over their roosting site, and perform their wheeling stunts before they roost for the night.