Lecture 21: Reproductive "skew" Theory

Front 1

What's the point of the reproductive skew theory?

Back 1

it attempts to explain the reproductive partitioning within animal societies according to the ECOLOGICAL SOCIAL and GENETIC attributes

Front 2

What is a high skew society? low skew?

Back 2

High- one or a few breeders strongly dominate the reproduction

Low- reproduction is shared more equitably

Front 3

What are transactional models of skew? Give an organismal example.

Back 3

the dominant breeders of the society "pay" subordinates (by yielding reproduction) to stay in the group and cooperate peacefully. ex. Paper wasps

Front 4

What are the 2 kinds of reproductive incentives that dominants can provide to subordinates?

Back 4

1) staying incentive--a fraction of the reproduction just sufficient to guarantee that the subordinate stays and helps the dominant vs. leaves to breed solitarily

2) peace incentive--a fraction of the reproduction just sufficient to guarantee that the subordinate cooperates peacefully instead of fighting to the death for complete control of the group's resources.

Front 5

Define all 4 variables in the staying incentive model where the dominant is alpha and subordinate is beta:
sol, lone, group, r, p

Back 5

sol = subordinate's expected reproductive success if it breeds solitarily
lone = the dominant's reproductive success if the subordinate does not join it
group = the dyad's total reproductive output if the subordinate joins
r = relatedness b/w the 2
p = minimum fraction of group's total reproduction

Front 6

Under what condition will the subordinate require no staying incentive (it will stay even if it gets 0 offspring)?

Back 6

if sol < or = r(group-lone) b/c then the numerator of Ps will be less than or equal to 0

Front 7

As the relatedness between subordinate and dominant increases, the staying incentive ____________.

Back 7

Declines (thus, skew increases)

Front 8

Staying incentive will _______ as the group output (group) increases, the lone dominant's output (lone) decreases, and as a solitary subordinate's output (sol) decreases

Back 8

decrease (skew increases)

Front 9

This is all in the subordinate's point of view but when will the dominant yield the required staying incentive?

Back 9

if sol + lone < group

Front 10

What will happen if this inequality is satisfied?

Back 10

the dominant will yield the minimal staying incentive to the subordinate. NOT GROUP SELECTION...acted on individual genetic interests

Front 11

What's an organism that practices staying incentive?

Back 11

paper wasps

Front 12

the subordinate gets a bigger staying incentive as:

Back 12

S increases, G decreases, L increases, r decreases

Front 13

How would you get complete skew (in dominant's point of view)?

Back 13

if s < r (s-l)

Front 14

the group dissolves if

Back 14

s > g-l

Front 15

In pure tug of war outcomes, what part does relatedness play on skew?

Back 15

hardly at all (dominant just doesnt push as hard but neither does subordinate)

Front 16

skew increases as...

Back 16

G increases and r increases

Front 17

In the tug of war model (aka allopine bees), what's the relationship b/w group output and r

Back 17

group output significantly increases as r increases and decreases with increasing subordinate abilities

Front 18

which model is more prevelant among humans (tug of war or transactional?)

Back 18

transational