Chap.08 Kinship

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Chap.08 Kinship

• ??? (Ayo) ??
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Kinship

• Kinship and animal behavior
• Kinship theory
• Relatedness and inclusive fitness
• Family dynamics
• Conflict within families
• Parent-offspring conflict
• Sibling rivalry
• Kin recognition
• Matching models
• Rule-of-thumb models of kin recognition

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Kinship and animal behavior

• Beldings ground squirrels give alarm calls when
  a predator is spotted.
• Alarm calls are most often emitted by females
  (Fig. 8.3)
• Females are surrounded by relatives, while adult
  males are generally in groups that do not contain
  their genetic relatives (Fig. 8.4)
• Beldings ground squirrel groups are typically
  made up of mothers, daughters, and sisters who
  cooperate with one another in a variety of
  contexts. Males that emigrate into such groups
  cooperate to a much smaller degree.

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In Beldings ground squirrels, females (A) are
much more likely than males to emit alarm calls
when predators are sighted. Such alarm calls
warn others, including female relatives and their
pups (B)
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Homicide(??) in humans

• 512 homicide cases occurring 1972 in Detroit,
  Michigan
• 127 (25) of these murders were committed denote
  as relatives.
• However, the police classify in-laws, and even
  boyfriend-girlfriend pairs, as relatives, rather
  than limiting this category to genetic kin.
• Only 6 of the murders involved relatives.
• ????????????, (Table 8.1)

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Genetic relatives rarely kill each other
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Kinship theory

• The modern study of animal behavior and evolution
  began in the early 1960s, when W. D. Hamilton,
  one of the leading evolutionary biologists of the
  twentieth century, published his now famous
  papers on genetic kinship and the evolution of
  social behavior.
• These papers formalized the theory of inclusive
  fitness or kinship theory and revolutionized
  the way scientists understood evolution and
  ethology.

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A classic case of helping genetic relatives is
that of mothers feeding their young. In bank
swallows, young chicks remain at the nest, and
mothers remember the location of their nests so
that they can return after foraging to feed
youngsters there
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Relatedness and inclusive fitness

• r genetic relatedness (Fig. 8.6)
• Inclusive fitness direct indirect fitness
• Hamiltons rule
• ( ? r b)- c gt 0
• b the benefit
• c the cost accrued to the individual expressing
  the trait

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The effects of helping kin (Fig. 8.7)

• Using groups of gray-crowned bablers that ranged
  from an initial size of six to eight individuals,
  Brown and his colleagues removed all but one of
  the nonreproductive helpers from the experimental
  groups, while leaving the number of
  nonreproductive helpers in the control groups
  unchanged.
• Reproductive success, as measured by the number
  of fledglings, was significantly lower in the
  experimental group because they had fewer helpers.

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Family dynamics

• The building blocks for family dynamics (Fig.
  8.8)
• Inclusive fitness (kin selection theory)
• Ecological constraints theory
• Reproductive skew theory
• Biological families (15 hypotheses) (Table 8.2)

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Biological families (15 prediction)

• 1. Family dynamics will be unstable,
  disintegrating when acceptable reproductive
  opportunities materialize elsewhere.
• 2. Families that control high-quality resources
  will be more stable than those with lower-quality
  resources. Dynasties may form.
• 4. Cooperative breeding will be expressed to the
  greatest extent between those family members that
  are the closest genetic relatives.
• 9. replacement mates (stepparents) will invest
  less in existing offspring than will biological
  parents.

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Family dynamics (prediction 1)

• 1. Family dynamics will be unstable,
  disintegrating when acceptable reproductive
  opportunities materialize elsewhere.
• This is the most basic prediction made by Emlen,
  as it focuses on fundamental costs and benefits
  associated with family life.
• One technique for experimentally examining
  prediction 1 is to create new, unoccupied
  territories and examine whether mature offspring
  leave their natal area to live in such newly
  created areas. (Superb fairy wren) (Fig. 8.9)
  they did so, within 6 hours.

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Family dynamics (prediction 2)

• 2. Families that control high-quality resources
  will be more stable than those with lower-quality
  resources. Dynasties may form.
• ??acorn woodpeckers (Fig. 8.11)
• Territories varied from less than a 1,000 to
  greater than 3,000 storage holes for acorns.
• Individuals on territories with lots of storage
  holes produced a greater average number of
  offspring (Fig. 8.12)
• In the areas with more than 3,000 storage holes,
  27of the young remained on their natal
  territories and helped their relatives, while
  only 2 of the young on territories with fewer
  than 1,000 holes stayed.

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Prediction 2 to human family dynamics

• Well-to-do families being more stable than poorer
  families?
• If a stable family is defined in terms of
  co-residence, then this prediction is not
  supported.
• Wealthier individuals did keep in touch with
  relatives more often than did lower-income
  individuals (Fig. 8.13)
• High-income families are more likely to maintain
  social ties at some level and to engage in
  exchange.

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Family dynamics (prediction 4)

• 4. Cooperative breeding will be expressed to the
  greatest extent between those family members that
  are the closest genetic relatives.
• ??white-fronted bee-eater kinship (Fig. 8.14)
  and helping close relatives (Fig. 8.15)

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Haplodiploid genetic system

• Honeybee policing (Fig. 8.16)
• Haploid males Females, diploid
• (A) while the queen typically lays the eggs in
  the honeybee colony, workers also attempt to lay
  unfertilized eggs.
• (B) when an egg laid by a worker is detected by
  worker police, it is eaten or destroyed. Such
  policing has inclusive fitness benefits
  associated with it.

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(A) The wasp in the middle of the photo is a
worker who has just laid an egg. (B) here a
worker is eating another workers egg. Policing
is much more common in wasp colonies where the
queen has mated with many males.
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Effectiveness of policing

• 10 species, 9 species of wasps and the honeybee.
• The more effective policing was at removing
  worker eggs, the less often workers attempted to
  reproduce (Fig. 8.19)

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Family dynamics (prediction 9)

• 9. replacement mates (stepparents) will invest
  less in existing offspring than will biological
  parents.
• Child abuse and genetic relatedness in humans
  (Fig. 8.20)
• (A) two natural parents
• (B) one natural and one stepparent

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Conflict within families

• Parent-offspring conflict
• How much aid to give to any particular offspring?
  (parental investment)
• And mating systems in primates
• In-utero conflicts in humans
• Sibling rivalry (??,??)

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And mating systems in primates

• The hypothesis
• offspring will attempt to extract more resources
  from patents in polyandrous systems than in
  monogamous systems.
• Fetuses grew faster in utero (taking more
  maternal resources) in polyandrous primate
  species
• Because sperm competition is more intense in
  polyandrous species, males in such species tend
  to have larger testes.
• Testes size can often be used as a proxy for the
  degree of polyandry.
• Fetal growth rate is positively corrected with
  the testes size. (Fig. 8.21)

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While the patent-offspring relationship is
usually cooperative (A), parent-offspring
conflict can occur, even in utero as shown by an
ultrasound (B)
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Sibling rivalry

• Sib-sib conflict. (Fig. 8.23)
• Kin selection theory predicts that individuals
  generally should not be very aggressive toward
  kin such as sibs.
• This is especially true when there are abundant
  resources. But if there are limited resources,
  conflict over the resources will increases as
  each individual is more related to itself (r1)
  than to its sib (r0.5)

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Sib-sib competition in egrets

• They lay their eggs in sequence, rather than all
  at one time. Thus, hatching order produces chicks
  that can differ in age by many days.
• Such age differences play a critical role in
  determining who emerges as the victor in sib-sib
  interactions, since chicks that hatch first start
  to feed sooner and hence receive more food, which
  leads to a weight advantage over chicks that
  hatch later (Fig. 8-25)
• Large size means better fighting ability (Fig.
  8-25B)

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Kin recognition

• Kin recognition in penguins (Fig. 8.26)
• Matching Model
• Template matching in tadpoles
• MHC, kinship, and templates
• Rule-of-thumb models of kin recognition

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Matching models

• Internal template
• Kin recognition matching models
• Individual 1 determines if individual 2 is kin or
  nonkin, depending on how closely individual 2
  matches the internal template of individual 1.
• Template matching in tadpoles
• Spadefoot toad tadpoles (Scaphiopus bombifrons)
• As in the spadefoot toad, two different tadpole
  morphs a carnivorous cannibal and an
  herbivirous omnivore exist in a number of
  amphibian species. Here a tiger salamander
  cannibal morph (right) is eating an omnivore
  morph (left). (Fig. 8.27)
• Kin recognition in spadefoot toads (Fig. 8.28)

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Spadefoot toad tadpoles come in two morphs
carnivorous and herbivorous. Individuals from
each tadpole morph were placed between two groups
of tadpoles, Herbivorous morphs preferred kin
sibs, while carnivorous morphs preferred nonkin.
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Carnivores

• Carnivores were not only more likely to eat
  unrelated individuals, but they were able to
  distinguish between relatives and nonrelatives by
  some sort of taste test.
• That is, carnivores were equally likely to suck
  relatives and nonrelatives into their mouths, but
  they released their relatives much more
  frequently than unrelated individuals.
• Cannibalistic toads were much less picky when
  they had been starved for 24 hours or more- that
  is, when they were very hungry, they would
  occasionally eat even genetic kin (Fig. 8.29)

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MHC, kinship, and templates

• MHC also plays a role in kin recognition.
• ??House mice (Mus musculus domesticus).
• When the female mice nest together, they all
  receive a benefit, which is protection from
  infanticidal males that sometimes attack and kill
  offspring that are not their own.
• Ninety percent of the females chose to nest
  communally. (kin recognition, MHC)

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Rule-of-thumb models of kin recognition

• ?????????,kin recognition rule, if it lives in
  you nest/cave/territory, then treat it like kin.
• Such kin recognition rules are subject to
  cheating
• ??,cowbirds and cuckoo birds (nest parasites)
• Spatial cues and kin recognition rules can often
  change through the lifetime of an individual.
• ??bank swallows,
• ??,in my burrow, it is likely kin
• ????,using distinctive vocal cues

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A mother dunnock is feeding a baby cuckoo.
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• Ayo NUTN website
• http//myweb.nutn.edu.tw/hycheng/