Biology 338: Lecture 15Spring 1997

Sexual Selection II

  1. Male-male competition
    1. Why do males compete?
    2. Results of male-male competition
      1. Dominance hierarchy
      2. Sexual dimorphism in body size and weaponry
      3. Sexual dimorphism in longevity
      4. Alternative male behaviors
        1. Act like a female
        2. Sneaker/"satellite" males
    3. Sperm competition
      1. Numerous copulations
      2. Increasing sperm count in ejaculate
      3. Mate guarding
      4. Sperm plug
      5. Removing sperm from previous male(s)
      6. "Kamikazee" sperm

  2. Case study: Three-pure-strategies of a marine isopod

  3. Case study: One-conditional-strategy (3 different tactics) of a scorpionfly

  4. Sex role reversal
    1. Mormon crickets
    2. Pipefish
    3. Jacanas
    4. Humans (?)