The effects of kin on female fertility in rural Gambia

Sear, Rebecca; Mace, Ruth; McGregor, Ian A.

doi:10.1016/s1090-5138(02)00105-8

Cited by 118 publications

(132 citation statements)

References 42 publications

Supporting

Mentioning

127

Contrasting

Order By: Relevance

“…If women have generally incurred greater fitness costs of reproduction, this life history tradeoff could help explain why they generally prefer fewer offspring than their husbands and reduce their fertility when they obtain more reproductive autonomy (23). Conflicts over family size often involve in-laws, and our findings help to explain why the presence of maternal in-laws lower a couple's fertility, whereas paternal in-laws increase it (55,56): maternal in-laws have more evolutionary interests in the mother's health and reproductive costs than paternal kin. Thus, sexual asymmetries in reproductive costs and investment may contribute to familial and sexual conflicts (20).…”

Section: Discussionmentioning

confidence: 69%

Differential fitness costs of reproduction between the sexes

Penn

Smith

2007

Proc. Natl. Acad. Sci. U.S.A.

154

116

View full text Add to dashboard Cite

Natural selection does not necessarily favor maximal reproduction because reproduction imposes fitness costs, reducing parental survival, and offspring quality. Here, we show that parents in a preindustrial population in North America incurred fitness costs from reproduction, and women incurred greater costs than men. We examined the survivorship and reproductive success (Darwinian fitness) of 21,684 couples married between 1860 and 1895 identified in the Utah Population Database. We found that increasing number of offspring (parity) and rates of reproduction were associated with reduced parental survivorship, and significantly more for mothers than fathers. Parental mortality resulted in reduced survival and reproduction of offspring, and the mothers' mortality was more detrimental to offspring than the fathers'. Increasing family size was associated with lower offspring survival, primarily for later-born children, indicating a tradeoff between offspring quantity versus quality. Also, we found that the costs of reproduction increased with age more for women than men. Our findings help to explain some puzzling aspects of human reproductive physiology and behavior, including the evolution of menopause and fertility declines associated with improvements in women's status (demographic transitions).maternal depletion ͉ menopause ͉ reproductive effort ͉ biodemography ͉ life-history tradeoff T he idea that reproduction confers fitness costs and benefits is central to evolutionary life-history theory, and evidence for reproductive costs has been found in a variety of species (1-3), including humans (4, 5). The evidence in humans is mixed (6) and controversial (7,8), and so more studies would help to solve this important question. Also, it is widely assumed that women have higher costs of reproduction than men because of enduring pregnancy, childbirth, and lactation, but evidence is lacking. Studies on women show that high parity and low birth spacing are associated with reduced health (9), postreproductive survival (10-13), and offspring quality (14, 15). There are only a few studies on men, and they suggest that men incur no fitness costs for reproduction (16,17). Taken together, the evidence supports the idea that women incur greater reproductive costs than men. However, the studies on men were mainly conducted on aristocrats and industrial societies, and men in most societies probably have not been so sheltered from the costs of reproduction. Thus, more studies are needed, especially large, longitudinal studies on couples living in preindustrial societies. Our aim was to examine the fitness costs of reproduction for husbands versus wives in an historical, 19th-century population in North America facing resource limitations, because a previous study suggested that both sexes in this population incurred fitness costs for reproduction (12).Determining the relative costs of reproduction for the sexes is relevant to understanding the evolution of some puzzling aspects of human physiology and behavior. For example, menopa...

show abstract

Section: Discussionmentioning

confidence: 69%

Differential fitness costs of reproduction between the sexes

Penn

Smith

2007

Proc. Natl. Acad. Sci. U.S.A.

154

116

View full text Add to dashboard Cite

show abstract

“…Some evidence indicates that sons, as the more expensive sex to rear, reduce investment in all later born offspring measured by reductions in birth weight (Nielsen et al 2008), adult height (Rickard 2008) and reproductive success (Rickard, Russell, andLummaa 2007, Sear, Mace, andMcGregor 2003). Sons may receive more investment from parents because they can benefit more, in terms of reproductive success, from parental resources than daughters can.…”

Section: Introductionmentioning

confidence: 99%

Does Wealth Increase Parental Investment Biases in Child Education?

Gibson

Sear²

2010

Current Anthropology

Self Cite

View full text Add to dashboard Cite

Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details.

show abstract

“…Alloparents are individuals other than the biological parents who invest in children. They have been shown to increase maternal reproductive success (Bereczkei and Dunbar 2002;Sear et al 2003) and aid in infant survivorship (Hawkes et al 1997;Ivey 2000). Studies have shown that humans are cooperative childrearers and that successful rearing of offspring may be dependent on alloparental assistance (Hrdy 2005;Ivey 2000).…”

mentioning

confidence: 99%

“…Alloparents in many species behave in a way that results in these maternal benefits, but Hrdy (2005) notes that lengthy human lifespans have made it difficult for many researchers to examine the overall impact that alloparents have on maternal reproductive success. However, several studies among humans illustrate that alloparents can lower maternal costs and increase maternal reproductive success (Flinn 1989;Kramer 2002;Sear et al 2003;Turke 1988).…”

mentioning

confidence: 99%

The effects of residential locality on parental and alloparental investment among the Aka foragers of the central African Republic

Meehan

2005

Hum Nat

114

View full text Add to dashboard Cite

In this paper I examine the intracultural variability of parental and alloparental caregiving among the Aka foragers of the Central African Republic. It has been suggested that maternal kin offer higher frequencies of allocare than paternal kin and that maternal investment in infants will decrease when alloparental assistance is provided. Behavioral observations were conducted on 15 eight-to twelve-monthold infants. The practice of brideservice and the flexibility of Aka residence patterns offered a means to test the effect of maternal residence on parental and alloparental investment. There was significant variation in the frequency of investment and who supplied care to infants depending on whether mothers resided with their kin or their husbands' kin. However, in spite of the variation in allocare, when all categories of caregivers were examined collectively, infants received similar overall levels of care.

show abstract

The effects of kin on female fertility in rural Gambia

Cited by 118 publications

References 42 publications

Differential fitness costs of reproduction between the sexes

Differential fitness costs of reproduction between the sexes

Does Wealth Increase Parental Investment Biases in Child Education?

The effects of residential locality on parental and alloparental investment among the Aka foragers of the central African Republic

Contact Info

Product

Resources

About