ScienceNews 7.2.2019

Evolutionarily, grandmas are good for grandkids — up to a point

Women may live past their reproductive years because they help their grandchildren survive

Grandmothers are great — generally speaking. But evolutionarily speaking, it’s puzzling why women past their reproductive years live so long.

Grandma’s age and how close she lives to her grandchildren can affect those children’s survival, suggest two new studies published February 7 in Current Biology.  One found that, among Finnish families in the 1700s–1800s, the survival rate of young grandchildren increased 30 percent when their maternal grandmothers lived nearby and were 50 to 75 years old.  The second study looked at whether that benefit to survival persists even when grandma lives far away. (Spoiler: It doesn’t.)

Read more in ScienceNews 7.2.2019 by Sujata Gupta

 

Other News

We are delighted to once again host PhD candidate Silke van Daalen, who will stay with us for most of September.

Laisk T, Tšuiko O, Jatsenko T, Hõrak P, Otala M, Lahdenperä M, Lummaa V, Tuuri T, Salumets A, Tapanainen JS:

Simon's latest work on the demography of grandmothers is now out in PLoS ONE. 

We were delighted to host Professors Martin Daly and Gretchen Perry for a day of excellent talks, with a particular focus on grandmothering and alloparental behaviour.

Robert Lynch is at the Human Behavior and Evolution Society (HBES) conference 2018 in Amsterdam

The manuscript "The transition to modernity and chronic disease: mismatch and natural selection" by Stephen Corbett, Alexandre Courtiol, Virpi Lummaa, Jacob Moorad and Stephen Stea

Two papers out now from Simon's PhD project!

1) Changes in the Length of Grandparenthood in Finland 1790-1959, published in the Finnish Yearbook of Population Reasarch. In this paper, the team investigated how the shared time between grandparents and grandchildren changed across the demographic transition and with industrialisation. This shared time was low and stable before these major events, and began to increase rapidly after they began.

2) Limited support for the X-linked grandmother hypothesis in pre-industrial Finland, published in Biology Letters. Here, we tested whether slight differences in relatedness via the X-chromosome might lead to differences the survival of male and female grandchildren with maternal or paternal grandmothers. Though two of three predictions were supported, we concluded that the X-linked grandmother hypothesis cannot account for lineage differences by itself. 

Our latest paper shows that early-life environment is associated with sex differences in adult mortality and expected lifespan. Out now in Ecology Letters:
http://doi.wiley.com/10.1111/ele.12888

Figure 3a+b, from Griffin et al. 2017

Our review of the contribution of human studies to evolutionary biology is out now in Proceedings of the Royal Society B:
http://rspb.royalsocietypublishing.org/content/284/1866/20171164