How do altruistic traits evolve

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How do altruistic traits evolve ?
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Alarm calls in Beldings Ground
Squirrels predator who calls escape/captured a
erial , 41/1 (2) terrestrial adult
28/11 (30) p lt 0.001
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Who calls? F gtgt M
F (with relatives) gt F (w/out relatives)
F (no offspring w/ relatives) gt F (no offspring,
no other relatives)
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Helping behavior White-fronted Bee-eater
Helpers make a difference B gt 0 Helpers dont
breed that year C gt 0
Who should they help?
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NEPOTISM
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Pied Kingfishers
One group are offspring of previous mating
primary helpers r 0.32
Another group isnt secondary helpers
Perhaps a third group that dont help anyone --
Delayers
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Direct Indirect Inclusive Fitness D r
B
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Kin selection and cooperative breeding in the
Seychelles Warbler, Acrocephalus
sechellensis habitat destruction severely
reduced population size Ne lt 50
population rebounded, habitat saturation
ecological constraint leads to helping behavior
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Komdeur 1992
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helpers parents
males females
Komdeur 1994 Proc Roy Soc 25647
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helper at the nest or reproductive parasite ?
Double and Cockburn 2003 Nature male helpers in
the superb blue fairy wren a-male plus up to 4
subordinate subordinates help feed young,
but young fledged does not increase
with helpers subordinate father 25 of
offspring in the nest due to extra-pair
copulations
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Kin selection and the evolution of cooperative
breeding Griffin and West 2003 Science
302634 relatively few studies demonstrate
kin discrimination, does kin selection really
drive helping behavior? meta-analysis of
species with adult helpers 15 birds, 3
mammals effect size magnitude of statistical
effect in individual studies effect size
r kin correlation between
probability/amount of help and genetic
relatedness r help correlation between
amount of help and benefit of help (offspring
production/survival)
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Bathyergus glaber
Eusociality is an extreme form of kin selection
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Reciprocal altruism in vampire
bats Wilkinson 1984 Nature
308181 live in aggregations of females
and offspring potential long-term associations
between group members food (blood) is
unpredictable 7-33 fail to feed does
relatedness /or familiarity influence
food-sharing ?
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deme 1 deme 2 n20 n20
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a 0.25, s 0.75 a 0.75, s
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deme 1 deme 2 n20 n20
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a 0.25, s 0.75 a 0.75, s
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