Lecture 11 Flashcards
Primate Habitats
- Gallery Forest
- Tropical Rainforest or Dry Forest
- Savanna
- Woodland
Primate Diets
- Plants
- Animals
- Fungi
- Minerals
Why do we care about ecology?
Informs our understanding of primate social and mating systems
Wrangham’s Socioecological Model
A framework for the evolution of primate social and mating systems from a behavioral ecology perspective
What is a social system?
The number of males and females that live and interact
Traits of a Social Group
- Spatial and Temporal Proximity
- Coordination of activities
- Recognition of group members
- Greater: Tolerance, Communication, Interaction, and Cooperation among group members than among non group members
Benefits of Living in a Group
- More food access
- Decreased predation
- Increased access to mates
- Safety for rearing offspring
Costs of Living in a Group
- Increased competition for food and resources
- Increased competition for mates
- Increased risk of predation
- Increased exposure to disease and parasites
Social System __ Mating System
DOES NOT EQUAL
Monogamy (mating system)
One Male and One Female
Polyandry (mating system)
Multiple Males and One Female
Polygyny (mating system)
One Male and Multiple Females
Polygynandry (mating system)
Multiple Males and Females
Mating Systems
- Mating may occur with or without long-term social relationships.
- Observed mating system does not equal true mating system
- Males and Females often have different criteria and preferences for mates
What do females want?
- Resources
- Mate Choice
- Help with Baby Care
- Babies not killed
What do males want
- Mating Opportunities!
- Avoid Baby Care (so they can mate more)
- Paternity Certainty
- Only their babies to survive
- Kill babies fathered by rival males
Larger Gamete
- Female
- Bias towards more investment in each gamete
- Many females retain fertilized gamete for further investment
- Female fitness depends on quality of offspring
Smaller Gamete
- Male
- Bias towards more investment in number of gametes
- Male fitness depends on number of fertilizations
How can females improve access to resources?
- Defend a solitary range or form with larger groups to overtake smaller groups
- Joining larger groups leads to more competition, females often live in groups with female kin (kin selection), and dominance hierarchies
Costs of Dominance for Females
Time lost, wounds, and stress
Benefits of Dominance for Females
Access to resources, less harassment/stress, potentially pass on more genes
Pair Living (mode of male comp.)
Males invest in mate guarding rather than physically fighting
A male overlaps with several solitary females or single male groups (mode of male comp.)
Males invest heavily in fighting ability and strive to keep other males out
Multi Male Groups (mode of male comp.)
Within group competition for access to females and males invest in both fighting ability and fertilization ability
Male Sexually Selected Traits
- Comp with Males: large body size, weapons, vocalizations, large testes and sperm plugs
- Mate choice by Females: ornaments, vocalizations, odor
Female Sexually Selected Traits
- Comp with other Females: usually lest direct contest competition for mates among females and instead compete to be more attractive to males
- Mate choice by males: ornaments, sexual swellings, and odor
Female Counter Strategies
- Large and brightly colored sexual swellings to advertise fertility
- Affiliate and mate with a few male “friends”
- Concentrate mating with a single male to ensure paternity certainty
- Established alliances with female friends
Why do primates live in so many kinds of social and mating systems
- Optimization resulting from competition within sexes and between sexes (what males and females want)
- Resources
