Social Relations

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Chapter 7

• Social Relations

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Behavioral Ecology

• The study of social relations of animals
• Sociobiology studying social relations in the
  context of fitness
• Mate choice and sociality are key aspects

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Mate Choice Sexual Selection
Sexual Selection differences in reproductive
rates based on differences in mating
success Intrasexual Selection based on
competition Intersexual Selection based on
choice by the mate, guppies
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Mate Choice Predation
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Mate Choice Sexual Selection
Male scorpionflies that offer medium or large
crickets as offerings have a higher mating
success rate
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Mate Choice Sexual Selection
Male scorpionflies seek to obtain crickets to
have as offerings for mates larger males tend to
get the crickets and have a greater success in
mating.
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Unequal Mating in Plants
Pollen donors have unequal success in siring
seeds, the position of their seeds in the pod,
and seed weight in wild radish in a greenhouse
experiment
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Plant Mating Unequal Seed Set
This field experiment shows that some pollen
donors set more seeds than other pollen donors
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Plant Mating Interference Competition
Pollen can interact in a flower and affect the
ability of competitor pollen to germinate
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Sociality Cooperative Breeders
Inclusive Fitness The individuals overall
fitness is determined by the success of itself as
well as that of its relatives. Kin Selection
Behaviors that benefit relatives that are not the
individuals offspring. Example green
woodhoopies stay at home to help defend
territories and raise relatives young.
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Sociality Cooperative Breeders
Male African lions live in coalitions that help
to raise young. The top ranked males do most of
the siring, while third and fourth ranked males
do very little siring.
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Sociality Cooperative Breeders
While low ranked individuals do little siring,
they are often grouped with relatives. Therefore
. By helping to raise relatives they are
increasing their inclusive fitness.
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Eusocial Species
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Summary

• Mate choice and competition can result in
  selection for traits in individuals sexual
  selection
• Sociality is generally accompanied by cooperative
  feeding, defense of the social group, and
  restricted reproductive opportunities