Male mating choices: The drive behind menopause?

Area of Science:

• Evolutionary biology
• Human evolution
• Reproductive science

Background:

• Humans exhibit greater longevity and a distinct postmenopausal stage compared to other great apes.
• The evolutionary drivers of human menopause, or old-age infertility in females, remain a subject of scientific inquiry.
• Previous research proposed male mating preferences for younger females as a key factor in menopause evolution.

Purpose of the Study:

• To re-evaluate the hypothesis that ancestral male mating choices drove the evolution of menopause.
• To investigate the robustness of the male-mate-choice hypothesis using a mathematical modeling approach.
• To explore the conditions under which male preference for younger mates could lead to female infertility.

Main Methods:

• Development of an ordinary differential equations (ODEs) model analogous to a prior agent-based model (ABM).
• Replication of key findings from Morton et al. (2013) using the ODE system.
• Extensive sensitivity analysis across various parameters and initial conditions to test hypothesis robustness.

Main Results:

• The ODE model confirmed the qualitative conclusions of the original ABM under specific conditions.
• Sensitivity analysis revealed that even minor deviations from exclusive mating preference for young females counteract menopause evolution.
• The study challenges the sufficiency of the male-mate-choice hypothesis alone.

Conclusions:

• The male-mate-choice hypothesis, as proposed, is likely incomplete in explaining the evolution of menopause.
• Further explanations are needed for the evolutionary stability of an exclusive male mating strategy with young females.
• Additional factors beyond male preference are likely involved in the evolution of human female post-reproductive lifespan.