Intrasexual vs. intersexual (epigamic) sexual selection Mating preferences in Drosophila and pigeons...

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ection Mating preferences in Drosophila and pigeons Certainty of Maternity, Uncertainty of Paternity “Battle of the sexes” Cuckoldry —> jealousy Desertion —> Mating Rituals, Complex Courtship Sex that invests most in most choosy about mates Natural selection produces a correlation between male genetic quality and female preference “Sexy son” phenomenon (females cannot afford to mate with males that are not attractive to other ales) Mating systems, monogamy, polygamy, polygyny eshold Marsh nesting (wrens, blackbirds, jacanas) Pinniped harems and sexual size dimorphisms Floating populations of non-breeding males

Transcript of Intrasexual vs. intersexual (epigamic) sexual selection Mating preferences in Drosophila and pigeons...

Page 1: Intrasexual vs. intersexual (epigamic) sexual selection Mating preferences in Drosophila and pigeons Certainty of Maternity, Uncertainty of Paternity “Battle.

Intrasexual vs. intersexual (epigamic) sexual selection

Mating preferences in Drosophila and pigeons

Certainty of Maternity, Uncertainty of Paternity

“Battle of the sexes”

Cuckoldry —> jealousy

Desertion —> Mating Rituals, Complex Courtship

Sex that invests most in most choosy about mates

Natural selection produces a correlation between

male genetic quality and female preference

“Sexy son” phenomenon (females cannot afford to mate

with males that are not attractive to other females)

Mating systems, monogamy, polygamy, polygyny threshold

Marsh nesting (wrens, blackbirds, jacanas)

Pinniped harems and sexual size dimorphisms

Floating populations of non-breeding males

Handout 5

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Red-eyed Vireo

Ecological sexual dimorphisms

Page 3: Intrasexual vs. intersexual (epigamic) sexual selection Mating preferences in Drosophila and pigeons Certainty of Maternity, Uncertainty of Paternity “Battle.

A. J. Marshall

Page 4: Intrasexual vs. intersexual (epigamic) sexual selection Mating preferences in Drosophila and pigeons Certainty of Maternity, Uncertainty of Paternity “Battle.
Page 5: Intrasexual vs. intersexual (epigamic) sexual selection Mating preferences in Drosophila and pigeons Certainty of Maternity, Uncertainty of Paternity “Battle.
Page 6: Intrasexual vs. intersexual (epigamic) sexual selection Mating preferences in Drosophila and pigeons Certainty of Maternity, Uncertainty of Paternity “Battle.
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Four Possible Situations Involving an Individual’s Behavior and Its Influence on a Neighbor________________________________________________________________

Neighbor(s) Gain Neighbor(s) Lose________________________________________________________________Individual Gains Pseudo-altruistic behavior Selfish behavior

(kin selection) (selected for)________________________________________________________________Individual Loses True altruistic behavior Mutually disadvanta-

(counterselected) geous behavior (counterselected)

_________________________________________________________________

Page 8: Intrasexual vs. intersexual (epigamic) sexual selection Mating preferences in Drosophila and pigeons Certainty of Maternity, Uncertainty of Paternity “Battle.

W. D. Hamilton (1964)

Kin Selection

Inclusive Fitness

Hamilton’s rule: r n b – c > 0

r = coefficient of relatedness

n = number of relatives that benefit

b = benefit received by each recipient

c = cost suffered by donor

r n b > c

“Adaptive Geometry of a Selfish Herd”

Page 9: Intrasexual vs. intersexual (epigamic) sexual selection Mating preferences in Drosophila and pigeons Certainty of Maternity, Uncertainty of Paternity “Battle.

“Adaptive Geometry of a Selfish Herd”

Page 10: Intrasexual vs. intersexual (epigamic) sexual selection Mating preferences in Drosophila and pigeons Certainty of Maternity, Uncertainty of Paternity “Battle.

Eusocial InsectsHymenoptera (“thin wings”)

Ants, bees, wasps, hornets

Workers are all females

Haplodiploidly

Isoptera (“same wings”)

Termites (castes consist of both sexes)

Endosymbionts

Parental manipulation

Cyclic inbreeding

Page 11: Intrasexual vs. intersexual (epigamic) sexual selection Mating preferences in Drosophila and pigeons Certainty of Maternity, Uncertainty of Paternity “Battle.

Kin selection, inclusive fitness

Hamilton’s rule: r n b > c

(coefficient of relatedness)

Pseudo-altruistic behavior

Eusocial Insects

Hymenoptera (“thin wings”)

Ants, bees, wasps, hornets—all workers are females

Haplodiploidly

Isoptera (“same wings”)

Termites (castes consist of both sexes)

Endosymbionts

Parental manipulation

Cyclic inbreeding

“Adaptive Geometry of a Selfish Herd”

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White-Fronted Bee Eater, Kenya

Page 13: Intrasexual vs. intersexual (epigamic) sexual selection Mating preferences in Drosophila and pigeons Certainty of Maternity, Uncertainty of Paternity “Battle.

White-Fronted Bee Eater Colony

Female tossing out an egg

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Helpers at the Nest in White-Fronted Bee Eaters in Kenya__________________________________________________________________Breeders r * Number of Cases % Cases__________________________________________________________________Father x Mother 0.5 78 44.8Father x Stepmother 0.25 17 9.8Mother x Stepfather 0.25 16 9.2Son x Nonrelative 0.25 18 10.3Brother x Nonrelative 0.25 12 6.9Grandfather x Grandmother 0.25 5 2.9Half brother x Nonrelative 0.13 3 1.7Uncle x Nonrelative 0.13 2 1.1Grandmother x Nonrelative 0.13 1 0.6Grandson x Nonrelative 0.13 1 0.6Great grandfather x Nonrelative 0.13 1 0.6Nonrelative x Nonrelative 0.0 20 11.5Total 174 100.0__________________________________________________________________* r = coefficient of relatedness.

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Reciprocal Altruism (Trivers 1971) Donor ––> Recipient

Small costs, large gains, reciprocated

Sentinels

Robert Trivers

Biological basis for our sense of justice?Friendship, gratitude, sympathy, loyalty, betrayal, guilt,

dislike, revenge, trust, suspicion, dishonesty, hypocrisy

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Game Theoretic Approaches

Costs versus benefits of behaviors

“tit for tat” strategy can lead to

cooperation

(“the future casts a long shadow back on

the present”)

Evolutionarily stable strategies = ESS

(a tactic that when

present in a population,

cannot be beaten)

Tit for Tat with

Forgiveness John Maynard Smith

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Evolution of Self Deceit

Subconscious mind

Polygraph playback experiments

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Evolution of Self Deceit

Subconscious mind

Polygraph playback experiments

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Evolution of Self Deceit

Subconscious mind

Polygraph playback experiments

Page 20: Intrasexual vs. intersexual (epigamic) sexual selection Mating preferences in Drosophila and pigeons Certainty of Maternity, Uncertainty of Paternity “Battle.

Evolution of Self Deceit

Subconscious mind

Polygraph playback experiments

Page 21: Intrasexual vs. intersexual (epigamic) sexual selection Mating preferences in Drosophila and pigeons Certainty of Maternity, Uncertainty of Paternity “Battle.

Helpers at the Nest in White-Fronted Bee Eaters in Kenya

Reciprocal Altruism (Trivers)

Donor ––> Recipient

Small costs, large gains, reciprocated

Sentinels, selfish callers

Biological basis for our sense of justice?

Friendship, gratitude, sympathy, loyalty, betrayal, guilt,

dislike, revenge, trust, suspicion, dishonesty, hypocrisy

Game Theoretic Approaches

Costs versus benefits of behaviors

“tit for tat” strategy + forgiveness can lead to cooperation

(“the future casts a long shadow back on the present”)

Evolutionarily stable strategies = ESS

Evolution of self deceit makes for better liars

Subconscious mind

Polygraph playback experiments