males use parental care as courtship in the sand goby, Pomatoschistus minutus

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males use parental care as courtship in the sand
goby, Pomatoschistus minutus
Colette M. St. Mary Kai Lindström Chris
Pampoulie University of Florida University of
Helsinki Marine Research Institute Reykjavík
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evolution of paternal care
Natural Selection
offspring survival
care
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benefits to offspring are also benefits to females
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evolution of paternal care
Natural Sexual Selection
offspring survival
mate attraction


future mating success
care
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sexual selection for care

• male care beyond natural selection optima
• males advertise parental care quality
• (e.g., Kirkpatrick 1985, Hoelzer 1989,Iwasa
  Pomiankowski 1999, Wolf et al. 1999)

• care may be a reliable signal
• (Tallamy 2002)

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working hypothesis

• paternal males use care as advertisement,
• i.e. courtship

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in fishes

• Nest guarding
• Egg cleaning fanning
• Multiple mating
• Filial cannibalism

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predictions

• natural selection (trade-off)
• care decreases with mating opportunities
• cannibalism increases with mating opportunities
• natural sexual selection (no trade-off)
• care is similar to courtship it increases with
  mating opportunities
• cannibalism increases as mating opportunities
  decrease

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evaluating the hypothesis

• manipulate future mating opportunities
• examine
• care
• courtship
• cannibalism
• compare results to predictions

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sand goby, Pomatoschistus minutus
Tvärminne
?
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sand goby, Pomatoschistus minutus

• males defend shell nests on sand bottom
• males build nest, fan and clean eggs
• number of spawns limited by nest size
• eggs require care
• annual species

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the experiment

Future mating opportunities Lg, females gt Lg, no
females gt Sm, females gt Sm, no females
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changes in care fanning
predicts NS care?w/mo fc?w/mo SS care?w/mo
courtship fc?w/mo
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changes in care nest building
care increases with mating opportunities
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courtship
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whole clutch filial cannibalism
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partial clutch filial cannibalism
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summary
predicts NS care?w/mo fc?w/mo SS care?w/mo
courtship fc?w/mo

• care increased with mating opportunities
• care similar to courtship
• males cannibalize clutches when mating
  opportunities are low

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conclusions directions

• males use care as courtship
• trade-offs between care and future mating
  opportunities NOT ubiquitous
• evidence of sexual selection
• do females prefer males that care more?

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