scholarly journals O brother, where art thou? Investment in siblings for inclusive fitness benefits, not father absence, predicts earlier age at menarche

2017 ◽  
Vol 13 (10) ◽  
pp. 20170464 ◽  
Author(s):  
Daniel Smith
Keyword(s):  
Inclusive Fitness ◽  
Human Life ◽  
Life History Evolution ◽  
Father Absence ◽  
Alternative Interpretation ◽  
Reproductive Age ◽  
Independent Effect ◽  
Age At Menarche ◽  
Parents And Children ◽  
Fitness Benefits

Numerous studies have indicated that father absence is associated with earlier age at menarche, with many evolutionary theories assuming that father absence is a causal factor that accelerates reproductive development. However, an alternative interpretation suggests that offspring may reproduce earlier in the presence of half- or step-siblings as the indirect fitness benefits to investing in them are lower, relative to delaying reproduction and investing in full siblings. From this perspective, father absence may perform no causal role in facilitating the onset of menarche. Using data from the Avon Longitudinal Study of Parents and Children, I find that individuals with only half- or step-siblings reach reproductive age earlier than those with only full siblings, with no independent effect of father absence. These results suggest that inclusive fitness benefits to investing in siblings, rather than father absence, may predict variation in age at menarche. These results provide a greater understanding of the adaptive mechanisms involved in reproductive decision-making, as well as potential implications for human life-history evolution and cooperative breeding more broadly.

scholarly journals Inclusive fitness and differential productivity across the life course determine intergenerational transfers in a small-scale human society

2015 ◽  
Vol 282 (1803) ◽  
pp. 20142808 ◽  
Author(s):  
Paul L. Hooper ◽  
Michael Gurven ◽  
Jeffrey Winking ◽  
Hillard S. Kaplan
Keyword(s):  
Life History ◽  
Inclusive Fitness ◽  
Human Life ◽  
Intergenerational Transfers ◽  
Essential Element ◽  
Life History Evolution ◽  
Small Scale ◽  
Human Society ◽  
Extended Lifespan ◽  
The Life Course

Transfers of resources between generations are an essential element in current models of human life-history evolution accounting for prolonged development, extended lifespan and menopause. Integrating these models with Hamilton's theory of inclusive fitness, we predict that the interaction of biological kinship with the age-schedule of resource production should be a key driver of intergenerational transfers. In the empirical case of Tsimane’ forager–horticulturalists in Bolivian Amazonia, we provide a detailed characterization of net transfers of food according to age, sex, kinship and the net need of donors and recipients. We show that parents, grandparents and siblings provide significant net downward transfers of food across generations. We demonstrate that the extent of provisioning responds facultatively to variation in the productivity and demographic composition of families, as predicted by the theory. We hypothesize that the motivation to provide these critical transfers is a fundamental force that binds together human nuclear and extended families. The ubiquity of three-generational families in human societies may thus be a direct reflection of fundamental evolutionary constraints on an organism's life-history and social organization.

scholarly journals Sibling relatedness rather than father absence predicts earlier age at menarche in ELSPAC cohort

2019 ◽  
Vol 15 (6) ◽  
pp. 20190091 ◽  
Author(s):  
Peter Lenárt ◽  
Filip Zlámal ◽  
Lubomír Kukla ◽  
Jiří Jarkovský ◽  
Julie Bienertová-Vašků
Keyword(s):  
Longitudinal Study ◽  
Reproductive Development ◽  
Father Absence ◽  
Age At Menarche ◽  
Socioeconomic Differences ◽  
Distinct Population ◽  
Evolutionary Theories ◽  
The Past ◽  
Parents And Children ◽  
Avon Longitudinal Study

Many studies during the past 50 years have found an association between father absence and earlier menarche. In connection with these findings, several evolutionary theories assume that father absence is a causal factor accelerating reproductive development. However, a recent study analysing data from the Avon Longitudinal Study of Parents and Children (ALSPAC) found that father absence does not predict age at menarche when adjusted for sibling relatedness. In this study, we have replicated these results in the Czech section of the European Longitudinal Study of Pregnancy and Childhood (ELSPAC), which used the same questionnaires as ALSPAC to study a geographically distinct population. Our results support the conclusion that sibling relatedness rather than father absence predicts age at menarche. Furthermore, our results show that age at menarche in 1990s UK and Czech cohorts is very similar despite socioeconomic differences between the two countries.

scholarly journals Grandmothering and natural selection

2010 ◽  
Vol 278 (1704) ◽  
pp. 384-391 ◽  
Author(s):  
A. Friederike Kachel ◽  
L. S. Premo ◽  
Jean-Jacques Hublin
Keyword(s):  
Natural Selection ◽  
Inclusive Fitness ◽  
Human Life ◽  
Reproductive Period ◽  
Age At First Birth ◽  
Weak Selection ◽  
Wide Range ◽  
Grandmother Hypothesis ◽  
Fitness Benefits ◽  
Post Menopausal

Humans are unique among primates in that women regularly outlive their reproductive period by decades. The grandmother hypothesis proposes that natural selection increased the length of the human post-menopausal period—and, thus, extended longevity—as a result of the inclusive fitness benefits of grandmothering. However, it has yet to be demonstrated that the inclusive fitness benefits associated with grandmothering are large enough to warrant this explanation. Here, we show that the inclusive fitness benefits are too small to affect the evolution of longevity under a wide range of conditions in simulated populations. This is due in large part to the relatively weak selection that applies to women near or beyond the end of their reproductive period. However, we find that grandmothers can facilitate the evolution of a shorter reproductive period when their help decreases the weaning age of their matrilineal grandchildren. Because selection favours a shorter reproductive period in the presence of shorter interbirth intervals, this finding holds true for any form of allocare that helps mothers resume cycling more quickly. We conclude that while grandmothering is unlikely to explain human-like longevity, allocare could have played an important role in shaping other unique aspects of human life history, such as a later age at first birth and a shorter female reproductive period.

scholarly journals Longitudinal changes in reproductive hormones through the menopause transition in the Avon Longitudinal Study of Parents and Children (ALSPAC)

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ana Goncalves Soares ◽  
Fanny Kilpi ◽  
Abigail Fraser ◽  
Scott M. Nelson ◽  
Naveed Sattar ◽  
...  
Keyword(s):  
Multilevel Models ◽  
Reproductive Factors ◽  
Reproductive Hormones ◽  
Reproductive Age ◽  
Chronological Age ◽  
Age At Menarche ◽  
Natural Menopause ◽  
Parents And Children ◽  
Best Fitting ◽  
Menopause Transition

AbstractWe characterised changes in reproductive hormones—LH, FSH, SHBG and AMH—by chronological age and time around the menopause (reproductive age) in mid-life women and explored their associations with lifestyle and reproductive factors. We used data from 1608 women from a UK cohort who had repeat hormone measures and experienced a natural menopause. Multilevel models were used to assess: (i) changes in hormones (outcomes) by reproductive age and chronological age (these age variables being the key exposures) and (ii) associations of body mass index (BMI), smoking, alcohol intake, parity and age at menarche with changes in hormones by reproductive age. Both LH and FSH increased until ~ 5 and 7 years postmenopause, respectively, after which they declined, but not to premenopausal levels. SHBG decreased slightly until ~ 4 years postmenopause and increased thereafter. AMH decreased markedly before menopause and remained low subsequently. For all hormones, the best fitting models included both reproductive and chronological age. BMI, smoking and parity were associated with hormone changes; e.g., higher BMI was associated with slower increase in LH and FSH and decrease in AMH. Reproductive and chronological age contribute to changes in LH, FSH, SHBG and AMH across mid-life in women, and BMI, smoking and parity are associated with these hormone changes.

Father absence, age at menarche, and genetic confounding: A replication and extension using a polygenic score

2020 ◽  
pp. 1-12
Author(s):  
Gabriel L. Schlomer ◽  
Kristine Marceau
Keyword(s):  
Environmental Influence ◽  
Life History Strategy ◽  
Father Absence ◽  
Strategy Development ◽  
Age At Menarche ◽  
Polygenic Score ◽  
Parents And Children ◽  
Gene Environment ◽  
Prospective Longitudinal

Abstract Father absence has a small but robust association with earlier age at menarche (AAM), likely reflecting both genetic confounding and an environmental influence on life history strategy development. Studies that have attempted to disambiguate genetic versus environmental contributions to this association have shown conflicting findings, though genomic-based studies have begun to establish the role of gene–environment interplay in the father absence/AAM literature. The purpose of this study was to replicate and extend prior genomic work using the Avon Longitudinal Study of Parents and Children (ALSPAC), a prospective longitudinal cohort study (N = 2,685), by (a) testing if an AAM polygenic score (PGS) could account for the father absence/AAM association, (b) replicating G×E research on lin-28 homolog B (LIN28B) variation and father absence, and (c) testing the G×E hypothesis using the PGS. Results showed that the PGS could not explain the father absence/AAM association and there was no interaction between father absence and the PGS. Findings using LIN28B largely replicated prior work that showed LIN28B variants predicted later AAM in father-present girls, but this AAM-delaying effect was absent or reversed in father-absent girls. Findings are discussed in terms genetic confounding, the unique biological role of LIN28B, and using PGSs for G×E tests.

Father absence, age at menarche, and sexual behaviors in women: Evaluating the genetic confounding hypothesis using the androgen receptor gene.

2019 ◽  
Vol 13 (3) ◽  
pp. 205-222 ◽  
Author(s):  
Gabriel L. Schlomer ◽  
Jessica Murray ◽  
Brianna Yates ◽  
Kerry Hair ◽  
David J. Vandenbergh
Keyword(s):  
Androgen Receptor ◽  
Sexual Behaviors ◽  
Receptor Gene ◽  
Father Absence ◽  
Androgen Receptor Gene ◽  
Age At Menarche

scholarly journals Trinidadian guppies use a social heuristic that can support cooperation among non-kin

2020 ◽  
Vol 287 (1934) ◽  
pp. 20200487 ◽  
Author(s):  
Safi K. Darden ◽  
Richard James ◽  
James M. Cave ◽  
Josefine Bohr Brask ◽  
Darren P. Croft
Keyword(s):  
Poecilia Reticulata ◽  
Social Space ◽  
Inclusive Fitness ◽  
Single Point ◽  
Theoretical Work ◽  
Evolution Of Cooperation ◽  
Social Partner ◽  
Proximate Mechanisms ◽  
Cognitive Limitations ◽  
Fitness Benefits

Cooperation among non-kin is well documented in humans and widespread in non-human animals, but explaining the occurrence of cooperation in the absence of inclusive fitness benefits has proven a significant challenge. Current theoretical explanations converge on a single point: cooperators can prevail when they cluster in social space. However, we know very little about the real-world mechanisms that drive such clustering, particularly in systems where cognitive limitations make it unlikely that mechanisms such as score keeping and reputation are at play. Here, we show that Trinidadian guppies ( Poecilia reticulata ) use a ‘walk away’ strategy, a simple social heuristic by which assortment by cooperativeness can come about among mobile agents. Guppies cooperate during predator inspection and we found that when experiencing defection in this context, individuals prefer to move to a new social environment, despite having no prior information about this new social group. Our results provide evidence in non-human animals that individuals use a simple social partner updating strategy in response to defection, supporting theoretical work applying heuristics to understanding the proximate mechanisms underpinning the evolution of cooperation among non-kin.

The evolution of childhood as a by-product?

2006 ◽  
Vol 29 (3) ◽  
pp. 288-289
Author(s):  
Peter Kappeler
Keyword(s):  
Life History ◽  
Life Histories ◽  
Nonhuman Primates ◽  
Homo Sapiens ◽  
Human Life ◽  
Life History Evolution ◽  
History Evolution ◽  
Linguistic Skills

The proposition that selective advantages of linguistic skills have contributed to shifts in ontogenetic landmarks of human life histories in early Homo sapiens is weakened by neglecting alternative mechanisms of life history evolution. Moreover, arguments about biological continuity through sweeping comparisons with nonhuman primates do not support various assumptions of this scenario.

scholarly journals Maternal Diet During Pregnancy and Blood Cadmium Concentrations in an Observational Cohort of British Women

Nutrients ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 904
Author(s):  
Caroline M. Taylor ◽  
Rita Doerner ◽  
Kate Northstone ◽  
Katarzyna Kordas
Keyword(s):  
Pregnant Women ◽  
Dietary Pattern ◽  
Maternal Diet ◽  
Reproductive Age ◽  
Food Groups ◽  
Parents And Children ◽  
Varied Diet ◽  
Observational Cohort ◽  
Adjusted Logistic Regression ◽  
The Uk

Few studies have investigated the extent to which diet predicts body Cd concentrations among women of reproductive age, and pregnant women in particular. The aim of this study was to examine diet as a predictor of blood Cd concentrations in pregnant women participating in the UK Avon Longitudinal Study of Parents and Children (ALSPAC). Whole blood samples were analysed for Cd (median 0.26 (IQR 0.14–0.54) µg/L). Dietary pattern scores were derived from principal components analysis of data from a food frequency questionnaire. Associations between dietary pattern scores and foods/food groups with blood Cd ≥ median value were identified using adjusted logistic regression (n = 2169 complete cases). A health conscious dietary pattern was associated with a reduced likelihood of B-Cd ≥0.26 µg/l (OR 0.56 (95% CI 0.39–0.81)). There were similarly reduced likelihoods for all leafy green and green vegetables (0.72 (0.56–0.92) when consumed ≥4 times/week vs ≤1 to ≥3 times/week) and with all meats (0.66 (0.46–0.95) when consumed ≥4 times/week vs ≤ once in 2 weeks). Sensitivity analysis excluding smokers showed similar results. The evidence from this study provides continued support for a healthy and varied diet in pregnancy, incorporating foods from all food groups in accordance with national recommendations, without the need for specific guidance.

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