lecture 23

Question 1

Factors that cause reproductive skew to increase

Answer 1

Group productivity (alpha get proportionally more resources because only has to give beta enough incentive to stay), constraints on solitary founding (makes it difficult to leave so beta settles for less), and relatedness (because beta can enjoy indirect fitness benefits)

Question 2

When is manipulation favored over cooperation?

Answer 2

r(N-1)∆R + ∆S > 0
N: group size
R: change in group reproductive output when individual leaves, negative term
S: change in reproductive output of the self
favored with self reproduction benefits outweigh the loss to the group; policing by group members can reduce S

Question 3

What happens when you add additional drones to population?

Answer 3

sister-brother relatedness not affected, but lowers relatedness between sisters; the more drones that queen mates with, the less related workers are to each other, making them overall more related to the queen; this makes workers preferentially help care for the queen’s eggs/brood, while destroying those of other workers; workers only police other workers in polyandrous nests

Question 4

Worker reproduction in monandric species

Answer 4

workers are more related to their sister workers than to the queen’s offspring, so they will promote the fitness of worker offspring; worker reproduction is observed in these species

Question 5

Conflict in bumblebees

Answer 5

workers will kill the queen to prevent her from laying more eggs and will eat the queen’s eggs because bumblebees only mate once; workers are more related to eggs of other workers so don’t want to help raise the queen’s offspring

Question 6

Game Theory

Answer 6

Used when fitness is frequency dependent; different from optimality models

Question 7

Prisoner’s dilemna

Answer 7

player has greatest payoff when defects regardless of what other player chooses; if other player also defects, will get 1 point instead of 0; if other player cooperates, will get 5 points instead of the 3 that they would get if both cooperate

Question 8

Evolutionary Stable Strategies (ESS)

Answer 8

based on game theory; appropriate when the best strategy depends on what everyone else is doing; developed to address economic problems

Question 9

Hawks & doves ESS model

Answer 9

not talking about actual hawks and doves, but rather about animals that exert certain types of behaviors within a population; hawks-settle conflicts by direct physical aggression; doves- settle conflict by convention, retreat if opponent attacks