Mating systems II

1
Mating systems II

• Sexual conflict
• Leks
• Hotspot
• Female preference
• Male aggregations
• Hotshots
• Kin selection

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Sexual conflict expectations
Environment quality alters relative and absolute
ranking of each mating system for each sex
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Sexual conflict in marmots
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Sexual conflicts in dunnock
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Females solicit male dunnocks to keep them on
territories
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Resource addition alters mating system of dunnock
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Leks

• Swedish for mating arena
• No male parental care
• No resource on territory
• Males aggregate and display at traditional sites
• Male mating success is highly skewed

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Males defend tiny territories on a lek
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Male mating success on leks is skewed
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Leks occur when females are not defensible
Leks -gt
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Lekking is often associated with frugivory in
birds
Lek
Exploded lek
Territory
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New World lekking birds
Cock-of-the-rock
Manakins
Bell birds
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Hypotheses for male clustering

• Hotspot
• males aggregate to maximize female encounter rate
• Female preference
• females prefer to select mates in aggregations
• males aggregate around most attractive male
  (hotshot)
• Expect center male to have highest mating success
• Kin selection
• Males aggregate around relatives

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The hotspot model
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Leks of leks suggest hotspots
Ochre-bellied flycatcher Red-capped
manakin Blue-crowned manakin Hermit hummingbird
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Sage grouse leks are at hotspots
Lek location
Female nest density
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Possible reasons for female preference to mate at
a lek

• Reduce predation
• No evidence in sage grouse
• Reduce mate searching costs
• More efficient comparison of males
• But largest gain occurs at small n
• Can copy choice of others

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Do leks recruit more females/male in kob?
No!
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Do leks recruit more females/male in ruff?
Sometimes!
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Are black grouse hotshots?
Yearly shift suggests male attractiveness, not
position, is important
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Related manakins on leks
Shorey et al. 2000 Nature 408352-353
Also in peacock, black grouse, satin bowerbirds,
wild turkeys
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The lek paradox

• If intense selection depletes genetic variation,
  what will females gain by choosing?
• Genetic variation must persist for traits
• Condition dependent traits differentially
  advertise genetic variation for condition, which
  is likely to be influenced by many genes