Post-reproductive survival in a polygamous society in rural Africa

Bodegom, D. van (2011)

Doctoral Thesis

Humans have a long post-reproductive life span. In this thesis we study this post-reproductive life span from an evolutionary perspective. Why did humans evolve such a long post-reproductive life span? We tested the hypothesis that men and women after age 50 are able to contribute to their fitness either direct by continued reproduction or indirect through improving the reproductive success of subsequent generations. In a prospective full kin analysis in the Upper East Region in Ghana, we studied the effect of different kin members on offspring production, survival and early growth patterns in a polygamous population that lives in an environment that could reflect our recent evolutionary past. We were able to confirm that post-reproductive survival in females indeed has a selective advantage. However, in this population, the advantage was not through increased survival of offspring as found by others, but through increased reproduction of their household. Also, we found that grandfathers, through continued reproduction up to high age created a selective pressure for old age survival. This direct effect was larger than the indirect effect of post-reproductive survival in women which could point to a more important role of men in the evolution of longevity than previously thought.

• Africa
• Polygamy
• Grandmother hypothesis
• Life history theory
• Post-reproductive life
• Evolution of ageing
• Ageing

• All authors: Bodegom, D. van
• Supervisor: Westendorp, R.G.J.
• Co-supervisor: Meij, J.J.; Thomése, G.C.F.
• Qualification: Doctor (dr.)
• Awarding Institution: Leiden University Medical Center (LUMC), Leiden University
• Date: 2011-11-02
• ISBN (print): 9789081791502