CHDV 23249 Lecture Notes - Lecture 18: Damage Tolerance
20 Feb 2017
School
Department
Course
Professor
Aggression and Territoriality (A)
Wednesday, February 15, 2017
10:30 AM
Territoriality
• type of competition that involves the behavioral exclusion of others from a specific area
o territory function varies across species
• feeding
• mate attraction
• courtship
• reproduction
o Benefits
• exclusion of competition for a resource
o Cost
• time lost (foraging attempts/prey caught)
• energetic costs (testosterone levels pretty high; weight effects)
• physiological costs (testosterone levels: immune suppression, aggressive behavior
- reproduction context)
o "Dear Enemy Effect"
• can reduce cost of territoriality
▪ territory owners recognize and tolerate the presence of known neighbors
▪ discrimination b/w neighbors and strangers is likely due to relative threats
that they pose
• What happens when individuals are in direct conflict over a resource?
o when the cost of fighting exceeds the value of the resources, the expected outcome is a
stable mixed ESS
• Displays of Aggression
o competitors differ in fighting ability, resource-holding potential (RHP), motivation,
experience
• RHP - the probability of successfully defending a resource
o object of game is to avoid a fight that you are likely to lose
• how do animals assess the probability of losing?
o Models of Conflict Resolution:
• Sequential Assessment Model (SAM)
▪ involves mutual agreement (a competitor assesses its own fighting ability
relative to that of its current opponent)
▪ assumes competitors know little about each other's fighting ability at the
start, but gain information as contest progresses
▪ contest ends when on competitor reaches the "giving up " line
▪ Predictions of Model:
• contests involve repeated rounds of matching displays to enable
updates of relative fighting ability estimates
• contests can escalate, consisting of phases of increasingly costly
behaviors
• contests are longer in duration (and/or progress through more
phases) when:
• competitors are more closely matched
• resources more highly valued
• Energetic War of Attrition (E-WOA)
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