Social Behavior

1
Social Behavior

• Questions and review

2

• Which of the following is essential for the
  stability of tit-for-tat cooperation (a) genetic
  relatedness among players, (b) the action of some
  form of group selection, (c) players that can
  identify other individual players, (d) players
  that can remember the past behavior of other
  players.
• C and D

3

• True or False The mere existence of relatives
  leaves a given animal with positive inclusive
  fitness even if it never reproduces on its own.
• False

4

• State Hamiltons Rule in its mathematical form,
  and then explain its meaning in words (define all
  variables, etc.).
• rb gt c, where r coefficient of relatedness, b
  reproductive benefit realized by the one being
  helped, and c cost to the helper in terms of
  lost personal reproduction.
• Hamiltons rule states that animals are
  more likely to help to rear young that are not
  their own if they are related to the offspring
  being helped, and if the help is actually helpful
  to the parent of the offspring. However, help
  will not be offered or given if the reproductive
  cost to the helper is greater than the benefit
  gained by that help.

5

• List 3 costs and 3 benefits of sociality in
  animals.
• Costs
• Larger groups may attract predators
• Greater competition for food
• Increased parasitic load and disease transmission
• Benefits
• Antipredator effects (vigilance, mobbing, etc.)
• Increased ability to find food
• Ability to hunt and kill large prey

6

• Consider the two player evolutionary game below.
  Players may cooperate or cheat. Indicate values
  for W, X, Y, and Z that would yield the following
  situations
• Coop Cheat
• Coop W,W Y,X
• Cheat X,Y Z,Z
• Evolutionary Stable Cheating in which cooperation
  would nevertheless be mutually beneficial to both
  players
• W 15 X 20 Y 5 Z 10
• Evolutionary Stable Cooperation ( no need for
  tit-for-tat behavioral rules)
• W 20 X 5 Y 15 Z 10