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Parental investment. Which sex cares? Sexual conflict Parent-offspring conflict. What is parental care?. building of nests or burrows. production of large, yolked eggs. care of eggs inside or outside parent. provisioning and defense of young. care after independence. Parental investment.
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Parental investment Which sex cares? Sexual conflict Parent-offspring conflict
What is parental care? building of nests or burrows production of large, yolked eggs care of eggs inside or outside parent provisioning and defense of young care after independence
Parental investment Fitness benefit or cost Benefit Cost 0 10 15 20 Days of care
Parental investment 10 8 Visits per nestling 6 0 Low Medium High Nectar = how much parental care reduces parent’s future fitness e.g., trade-off between caring for self versus offspring Palestine sunbird Markman, S., B. Pinshow, and J. Wright. 2002. The manipulation of food resources reveals sex-specific trade-offs between parental self-feeding and offspring care. Proc. R. Soc. Lond. B (2002) 269, 1931–1938
Sexual Conflict Mean Number of Offspring Females: Without male help 2.95 With male help 3.53 Males: 1 female (helping) 3.53 2 females (no help) 7.88 3 females (no help) 12.80 Marsh Wren Leonard, M.L. 1990. Polygyny in marsh wrens: asynchronous settlement as an alternative to the Polygyny Threshold Model. Am. Nat. 136:446-458.
Sexual Conflict Best strategy may differ for males versus females = ESS problem Valera F, Hoi H & Schleicher B (1997) Egg burial in penduline tits, Remit pendulinus: Its role in mate desertion and female polyandry. Behav Ecol 8: 20-27
Parent-offspring conflict Benefit (to self) Fitness benefit or cost Benefit (to parent) Cost 0 10 15 20 Days of care
Parent-offspring conflict Comparative evidence from begging displays
P-O Conflict in Pigs Confined pens (farrowing crates) Get-away pens Pajor, E.A. 1998. Parent-offspring conflict and its implications for maternal housing systems in domestic pigs. PhD thesis, McGill University.
Confined: piglets do better 1) nurse more 2) heavier 3) grow faster Get-away: mother does better 1) nurses less frequently 2) interval to oestrus shorter 3) lower weight loss