The trade-off between number and size of offspring in humans and other primates

Walker, Robert; Gurven, Michael; Bürger, Oskar; Hamilton, Marcus J.

doi:10.1098/rspb.2007.1511

Cited by 114 publications

(94 citation statements)

References 36 publications

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“…The quality-quantity trade-off has been empirically demonstrated in species that produce litters or clutches, where large litter size often leads to small offspring size, slow growth rates, and reduced survival, particularly under conditions of ecological stress (8)(9)(10)(11). Comparative analyses also support a negative interspecific relationship between reproductive rate and offspring size (12,13). The quality-quantity trade-off has rarely been examined in species for which single births are the norm, and for which reproductive rate is determined by the interval between successive births.…”

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confidence: 70%

Faster reproductive rates trade off against offspring growth in wild chimpanzees

Thompson

Muller

Sabbi

et al. 2016

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

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Life history theory predicts a trade-off between offspring quality and quantity. Among large-bodied mammals, prolonged lactation and infant dependence suggest particularly strong potential for a qualityquantity trade-off to exist. Humans are one of the only such species to have been examined, providing mixed evidence under a peculiar set of circumstances, including extensive nutritional provisioning by nonmothers and extrasomatic wealth transmission. Here, we examine trade-offs between reproductive rate and one aspect of offspring quality (body size) in wild chimpanzees (Pan troglodytes schweinfurthii), a species with long periods of infant dependence and little direct provisioning. Juvenile lean body mass, estimated using urinary creatinine excretion, was positively associated with the interval to the next sibling's birth. These effects persisted into adolescence and were not moderated by maternal identity. Maternal depletion could not explain poor offspring growth, as older mothers had larger offspring, and low maternal energy balance during lactation predicted larger, not smaller, juvenile size. Instead, our data suggest that offspring growth suffers when mothers wean early to invest in new reproductive efforts. These findings indicate that chimpanzee mothers with the resources to do so prioritize production of new offspring over prolonged investment in current offspring.life history | growth | reproduction | primates | weaning P arents face a fundamental life-history trade-off between producing more offspring and investing in the quality of each progeny (1-4). This offspring quality-quantity trade-off, along with a trade-off between reproductive investment and parental survival, means that maximizing reproductive rates is often not the strategy that maximizes fitness (5-7). The quality-quantity trade-off has been empirically demonstrated in species that produce litters or clutches, where large litter size often leads to small offspring size, slow growth rates, and reduced survival, particularly under conditions of ecological stress (8-11). Comparative analyses also support a negative interspecific relationship between reproductive rate and offspring size (12, 13). The quality-quantity trade-off has rarely been examined in species for which single births are the norm, and for which reproductive rate is determined by the interval between successive births. Such species are important tests of the model, as a slow breeding strategy suggests a particularly potent trade-off between offspring investment and reproductive rate. Understanding how individuals negotiate this trade-off can provide important insights into the evolution of reproductive biology and behavior.Data on humans are valuable because humans invest intensively in offspring, yet have highly variable reproductive rates. Many studies find the predicted negative relationship between reproductive rates and offspring growth or health (14-18) or demonstrate fitness maximization at intermediate levels of fertility (19-21). For example, when a water tap was ...

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confidence: 70%

Faster reproductive rates trade off against offspring growth in wild chimpanzees

Thompson

Muller

Sabbi

et al. 2016

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

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“…We already know, for example, that humans are subject to the same basic trade-off between offspring size and number as other mammals (Walker et al 2008). Hawkes et al (1998) found that humans fit the predicted value for the product of adult mortality rate and age at maturity, but differed in the product of birth rate and age at maturity.…”

Section: Introductionmentioning

confidence: 99%

Lifetime reproductive effort in humans

2009

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Lifetime reproductive effort (LRE) measures the total amount of metabolized energy diverted to reproduction during the lifespan. LRE captures key components of the life history and is particularly useful for describing and comparing the life histories of different organisms. Given a simple energetic production constraint, LRE is predicted to be similar in value for very different life histories. However, humans have some unique ecological characteristics that may alter LRE, such as the long post-reproductive lifespan, lengthy juvenile period and the cooperative nature of human foraging and reproduction. We calculate LRE for natural fertility human populations, compare the findings to other mammals and discuss the implications for human life-history evolution. We find that human life-history traits combine to yield the theoretically predicted value (approx. 1.4). Thus, even with the subsidized energy budget and uniqueness of the adult lifespan, human reproductive strategies converge on the same optimal value of LRE. This suggests that the fundamental demographic variables contained in LRE trade-off against one another in a predictable and highly constrained manner.

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“…Population models assume that parents make investment decisions that maximize reproductive success in the face of limited resources [1]. In other words, when certain constraints are met such as energy, effort or time invested in the provisioning of offspring, then it is difficult to invest in the production of additional offspring [2].…”

Section: Introductionmentioning

confidence: 99%

Demography Dynamics: Factors Affecting Number of Offspring and Male to Female Ratio in Greece

Lambrou¹

2016

JFMHC

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Abstract:Background: Population models assume that parents make investment decisions that maximize reproductive success in the face of limited resources. Aim: The aim of the current study was to investigate the dynamics of offspring and the patterns of male to female ratio in the urban area of Athens. In addition, the role of socioeconomic factors to their dynamics was examined. The study was conducted in the urban area of Athens. The target group consisted of children in the area's kindergartens. A total of 435 single parents or parent couples were investigated with respect to their socioeconomic background and the number of children. Result: The main factors affecting the number of children included the income which was influenced by both education and nationality. At the same time, nationality appeared to play a significant role in the male to female ratio with mixed couples manifesting the largest ratio. Conclusions: To the best of our knowledge, this is the first work in the literature examining the dynamics of offspring by calculating the effects of socioeconomic factors such as education, income and nationality. At the same time, such works are extremely important both towards the understanding of population dynamics but also towards policy making, which includes both demographical and fiscal policies.

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The trade-off between number and size of offspring in humans and other primates

Cited by 114 publications

References 36 publications

Faster reproductive rates trade off against offspring growth in wild chimpanzees

Faster reproductive rates trade off against offspring growth in wild chimpanzees

Lifetime reproductive effort in humans

Demography Dynamics: Factors Affecting Number of Offspring and Male to Female Ratio in Greece

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