Female Sexual Strategies in Chimpanzees R.M. Strumpf and C. Boesch Summary and presentation by: Aubrie DeBear, Neda Naimi & Cody Tyson Strumpf, R.M., Boesch, C. (2005). Does promiscuous mating preclude female choice? Female sexual strategies in chimpanzees (Pan troglodytes verus) of the Tai National Park, Cote d’Ivoire. Behav Ecol Sociobiol, 57,

Hypotheses Whether females express mate preferences Whether females are more selective at POP Whether female preferences differ inter- individually Influencing factors Strumpf, R.M., Boesch, C. (2005). Does promiscuous mating preclude female choice? Female sexual strategies in chimpanzees (Pan troglodytes verus) of the Tai National Park, Cote d’Ivoire. Behav Ecol Sociobiol, 57,

Results and Discussion Female rank and age Proceptivity rates in POP Eschewed males Non-preferred males Departing dominant male Most significant influencing factor Strumpf, R.M., Boesch, C. (2005). Does promiscuous mating preclude female choice? Female sexual strategies in chimpanzees (Pan troglodytes verus) of the Tai National Park, Cote d’Ivoire. Behav Ecol Sociobiol, 57,

Female Sexual Strategies More resisting of male solicitations during POP Increase mating with all males during Non- POP Graded signal hypothesis Mixed strategy Manipulation Strumpf, R.M., Boesch, C. (2005). Does promiscuous mating preclude female choice? Female sexual strategies in chimpanzees (Pan troglodytes verus) of the Tai National Park, Cote d’Ivoire. Behav Ecol Sociobiol, 57,

Critical Review Items: A – Interesting Points Promiscuity does not rule out selectivity, and in fact female chimpanzees may use both as a mixed strategy to attempt to influence which males will father their offspring (p. 519). Males are unaware of when a female is actually in POP, this means that they will not be sure of who sired the offspring. This hopefully leads to social support and less male aggression. The author indicated that female chimpanzees have a high proceptivity, or desire to reproduce, with males that were ascending in the social hierarchy at a fast pace. The fact that they have an ability to see this and predict it with great accuracy is fascinating. "Mate selectivity should be particularly important for female chimpanzees (Pan troglodytes), because of their extensive investment in offspring and limited reproductive potential. Chimpanzee inter-birth intervals average 4–6 years, infants have prolonged maternal dependence, and average female lifetime production of surviving off- spring is below five. However, contrary to this expectation, chimpanzee females do not seem particularly selective. Females mate with many males over the course of estrus, resulting in hundreds of copulations per conception." (pg 511) Strumpf, R.M., Boesch, C. (2005). Does promiscuous mating preclude female choice? Female sexual strategies in chimpanzees (Pan troglodytes verus) of the Tai National Park, Cote d’Ivoire. Behav Ecol Sociobiol, 57,

Critical Review Items: B – Weak or Unclear It was confusing that female chimpanzees had substantially higher proceptivity rates toward either the highest OR lowest ranking males during POP, excluding middle ranking males. This was just briefly mentioned, but not clearly explained. If females were more selective and choosy during POP, then why would they be just as proceptive to the lowest ranking males as highest ranking over the middle ranked males? "Although promiscuity entails risks, including decreased control over paternity, this strategy may benefit females by: (1) confusing paternity and discouraging infanticide ); (2) providing high quality genes through enhanced male-male and sperm competition, and (3) ensuring fertilization. Promiscuous mating may also reduce male aggression toward females and increase social support or protection from predators. Thus, while females may benefit from a promiscuous strategy, the expectation for choosiness remains, and the question arises as to whether promiscuous mating precludes female choice." pg ) This is confusing because they don't seem to understand why the female chimpanzee's aren't choosey and are promiscuous, but they identify three very important reasons for the female's survival and also the offsprings survival. So the promiscuity is very helpful in lengthening their lives and ensuring fertilization of the egg making sure the female get's pregnant. With such a small sample size I wonder if the significant results could even really be representative of that species of primates as a whole. For example, a few outliers could have had a drastic effect. Strumpf, R.M., Boesch, C. (2005). Does promiscuous mating preclude female choice? Female sexual strategies in chimpanzees (Pan troglodytes verus) of the Tai National Park, Cote d’Ivoire. Behav Ecol Sociobiol, 57,

Video Female Mating Strategy &feature=related Strumpf, R.M., Boesch, C. (2005). Does promiscuous mating preclude female choice? Female sexual strategies in chimpanzees (Pan troglodytes verus) of the Tai National Park, Cote d’Ivoire. Behav Ecol Sociobiol, 57,