Sexual Selection & Mate Choice

Sexual Selection & Mate Choice

1. SEXUAL SELECTION

   • Darwin 1871: The Descent of Man
   • INTRA-sexual
     • male-male competition
       • pre-mating: confrontation, collecting mates, displays
       • during: harassment, guarding
       • post-mating: mating plug, sperm competition
         • mating plug = gelatinous secretion left by males in female genital tract that harden/glues tract together. Female can excrete it - but it gives male's sperm time - often deciding factor in fertilisation
   • INTER-sexual
     • female choice
   • WHY DIFFERENT?
     • Male: sperm small + cheap
       • Reproductive success limited by females
     • females: eggs large + costly, internal fertilisation - gestation (25%), lactation (39%) (mammals)
       • Reproductive success limited by resources
         • Trivers 1972: mate that invests more is more choosy
     • Bateman 1948

2. MATE CHOICE

   • Male
     • Quantity
     • Mating oppurtunities
     • High fertility
     • Paternal certainty
   • Female
     • Quality
     • Resources
     • Can provide resources + supoort

3. UNIVERSAL MATE CHOICE PREFERENCES

   • Shackelford et.al. 2005: Universal dimensions of human mate preferences
     • rate importance 18 mate characteristics across 37 cultures
       • use PCA to identify underlying dimensions
     • RESULT: significant sex difference in 27/37 cultures
       • Women: social status, dependability, eductation, intelligence
       • Men: good looks, health, desire for home/children
     • DIMENSIONS
       • 1. Love v Status/Resources
         • M: mutual attraction/love
         • F: financial prospects, ambition
         • 27/37
       • 2. Dependable/Stable v Good Looks/Health
         • M: attractiveness, good housekeeper, good health
         • F: dependable, emotional stability, refinement
         • 30/37
       • 3. Education/Intelligence v Desire for Home/Children
         • M: desire for children, chastity
         • F: intelligent, similar political/educational backround
         • 20/37
       • 4.Sociability v Similar Religion
         • M: similar religious backround
         • F: sociability, pleasing disposition
         • 2/37