Handouts
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IB 146 – Spring 2004


Lecture 13: Cooperation and conflict in social groups
Defining sociality
Examples of cooperation in social groups (e.g., honeybees)
Examples of conflict in social groups (e.g., groove billed anis)
General types of groups (aggregations, reproductive pairs, kin groups)
Implications of group structure for:
How groups forms
Adaptive bases for group living
Potential for cooperation and conflict

Lecture 14: Natal philopatry and group formation
Defining natal philopatry
Costs vs benefits of natal dispersal – why do most juveniles disperse?
Costs vs benefits of natal philopatry – why do some juveniles stay home?
Conceptual frameworks for understanding natal philopatry:
Benefits of philopatry
Ecological constraints
Delayed dispersal threshold model
Testing the delayed dispersal threshold model – stripe backed wrens

Lecture 15: Ecology of sociality
Testing the delayed dispersal threshold model
Stripe backed wren example
Seychelles warbler example
Common ecological constraints:
Habitat saturation
Shortage of mates
Costs of reproducing alone
Costs of dispersing

Lecture 16: Alloparental care
Defining alloparental care
Singular breeding vs plural breeding alloparental species
Adaptive bases for alloparental care: two distinct questions
Why be philopatric?
Why provide alloparental care?
Benefits to breeders (do helpers really help?)
Current direct fitness benefits
Future direct fitness benefits
Benefits to alloparents (why provide alloparental care?)
Current indirect fitness benefits
Current direct fitness benefits
Future direct fitness benefits
Role of ecology and kinship in alloparental systems: pied kingfisher example

Lecture 17: Alloparental care (again)
Role of kinship in alloparental systems:
Continue with pied kingfisher example
White fronted bee eater example
Stripe backed wren example

Lecture 18: How important is kin selection?
Defining direct vs indirect fitness, inclusive fitness
Hamiltonian (indirect fitness) explanations for apparent altruism
Four types of social interactions: altruism, mutualism, selfishness, spite
Evidence that indirect fitness doesn’t explain all aspects of alloparental care:
Care doesn’t vary with helper relatedness to young
Not all alloparents are kin to young
Examples: pied kingfishers, meerkats, splendid fairy wrens, white browed scrubwrens
Re-evaluating relative importance of indirect fitness benefits in explaining alloparental care

Lecture 19: Reproductive skew
Defining reproductive skew
Low skew vs high skew societies – graphing patterns of direct fitness
What limits reproduction within social groups?
Extrinsic constraints
Intrinsic constraints
Models of reproductive skew:
Reproductive concessions model
Incomplete control model
Determining which model applies – meerkat example

Lecture 20: More reproductive skew
Role of kinship in reproductive skew
Matrifilial vs sororal societies (literature review)
Kinship among reproductive partners (meerkats)
Proximate mechanisms of reproductive skew (suppression)
Behavioral mechanisms
Physiological mechanisms
Scale of increasing severity of suppression

Lecture 21: Trends in sociality
General patterns that arise when comparing social species
Use group size as a starting point (axis for comparison)
Consider trends in:
Philopatry (degree and duration)
Ecological constraints (severity)
Kinship (mean among group members)
Indirect vs direct fitness benefits (relative importance)
Direct fitness graphs (lifetime measures of direct fitness)
Extent of reproductive skew (scale of 0 = low to 1 = high)
Mechanisms of suppression (behavioral vs physiological)
Extent of cooperation (number of activities)
Behavioral specialization (degree)
Morphological specialization (degree)
What are causal connections?