Tuesday, October 13, 2009

Menopause with a purpose   posted by Razib @ 10/13/2009 01:14:00 AM

Virpi Lummaa is at it again, Fitness benefits of prolonged post-reproductive lifespan in women:
Using complete multi-generational demographic records, we show that women with a prolonged post-reproductive lifespan have more grandchildren, and hence greater fitness, in pre-modern populations of both Finns and Canadians. This fitness benefit arises because post-reproductive mothers enhance the lifetime reproductive success of their offspring by allowing them to breed earlier, more frequently and more successfully. Finally, the fitness benefits of prolonged lifespan diminish as the reproductive output of offspring declines. This suggests that in female humans, selection for deferred ageing should wane when one's own offspring become post-reproductive and, correspondingly, we show that rates of female mortality accelerate as their offspring terminate reproduction.

The effect of a grandmother being around seems to be ~10% increase in the survival likelihood of grandchildren. Not trivial.

Update: Yep, it's an old paper. If you haven't read it, still work checking out Lummaa's work.