明日とロボット このページをアンテナに追加 RSSフィード


霊長類行動学11. オス同士の関係パターン


Primate Males

  • characteristics of male behavior
  • primary interest
    • reproductive success
    • enormous reproductive potential - skew
      • only limited by female resources

  • reproductive success
    • benefit of long life +
    • reproductive output. ie effort
    • how much energy you invest
    • more important
  • these tow are contingent to reproductive success is relative to other males.
    • (female compete for food for offspring)
    • but male, only thing they care is
  • one male's benefit if other male's loss
    • why?
    • sex ratio : 1:1
    • if you mate with more than one, some males loses chance
  • male sacrifice long life in order to maximize RS

male strategies is contingent with two things
  1. distribution of females in space and time - measure potential of competition.
    • operational sex ratio - refer to old note!
  2. distribution and strategy of other males
    • female counter strategies
      • males strategies are not always accepted by females
    • male strategy is divided into two
      1. contest (mostly) - fight against to exclude others
      2. scramble - deferred contest (sperm competition in promiscuity)
        • if dispersed
        • e.g., Gibon

  3. if females dispersed - males are dispersed, too.
  4. Polygynous mate guarding
    • range v. rove
      • over density period of time
    • Area x #females x p(female is receptive) x p(another male mate with other female)
      • low: stick to one female (e.g., Gibon)
      • high: male wanders around (e.g., Orangutan)
      • to maximize reproductive success
      • also works for groups, too.

  5. Gibon are rare in estrous, and female dispersed, so stick with one female.
    • remember: Monogamy is only when males were forced to be from some reasons
    • in Gibon's case, payoff is too high

female group size changes male's mating strategies

  • small female group size
    • single resident male
    • other males
    • reason why other males leaves is fighting against the resident male is an unstable strategy (game theory)
      • not enough benefit to risk because there are only few females

if mating is

  • seasonal - multi-male influx
    • small group of female
    • within all mate band - peaceful
    • end up with promiscuity mating
  • aseasonal
    • seek tenure




Connection: close