Continuously Recorded Suckling Behaviour and Its Effect on Lactational Amenorrhoea

Hw, Taylor; Vázquez-Geffroy, Margaret; Sj, Samuels; Taylor, Deanne

doi:10.1017/s0021932099002898

Cited by 21 publications

(20 citation statements)

References 19 publications

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“…In natural fertility populations, cessation of suckling usually occurs at some time before a child's third birthday with the onset of the mother's next pregnancy (26). More intense suckling and later introduction of solid food prolong lactational amenorrhea (27). Conversely, less intense suckling would shorten interbirth intervals and cause earlier weaning.…”

Section: Ontogeny Of Resource Transfersmentioning

confidence: 99%

Transfers and transitions: Parent–offspring conflict, genomic imprinting, and the evolution of human life history

Haig

2010

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

111

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Human offspring are weaned earlier than the offspring of other great apes but take longer to reach nutritional independence. An analysis of human disorders of imprinted genes suggests genes of paternal origin, expressed in infants, have been selected to favor more intense suckling than genes of maternal origin. The same analysis suggests that genes of maternal origin may favor slower childhood growth but earlier sexual maturation. These observations are consistent with a hypothesis in which slow maturation was an adaptation of offspring that reduced maternal fitness, whereas early weaning was an adaptation of mothers that reduced the fitness of individual offspring.Beckwith-Wiedemann syndrome | genomic imprinting | Prader-Willi syndrome | weaning E thnographic data suggest our ancestors consumed more food than they gathered until early adulthood and gathered more food than they consumed thereafter (1). Thus, hominin life history involved a transfer of resources from older producers to younger consumers. Lee modeled the consequences of these transfers for the evolution of age-specific mortality (2, 3). He found that transfers from older to younger individuals mitigate the force of selection against early deaths, because the death of a dependent youngster frees food for other group members, but intensify selection against late-life mortality, because the death of a productive elder reduces food for survivors.Lee's model assumed consumers and producers were genetically identical, except for new mutations (2). It was as if older producers could provision their younger selves. In sexual life cycles, however, resources are transferred between individuals who may share some, but not all, of their genes (4). If multiple donors transfer resources to multiple recipients, then each donor favors the distribution of resources that maximizes her inclusive fitness, but each recipient favors the distribution that maximizes his inclusive fitness. Individual consumers are predicted to take a larger share of production (if given the opportunity) than the quantity favored by donors. The paradigm of such conflict is the allocation of maternal investment among offspring. If a mother distributes resources in a manner that maximizes her fitness, then each offspring will favor a reallocation from sibs to itself (5). Genes that are expressed differently when inherited via ova than via sperm are predicted to mediate kin conflicts (6, 7). Therefore, the phenotypic effects of such imprinted genes will provide important clues about how transfers among kin have shaped human life history. Modeling Transfers Among KinPatterns of resource transfers within groups and gene transfers between groups are variable among modern human populations and were presumably variable among ancestral populations. Simplification of this complexity is necessary to gain theoretical insight into how resource and gene transfers interact. I will consider a simple gene-transfer model in which females move to new groups when they switch from being net consumers to net pr...

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Section: Ontogeny Of Resource Transfersmentioning

confidence: 99%

Transfers and transitions: Parent–offspring conflict, genomic imprinting, and the evolution of human life history

Haig

2010

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

111

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“…We chose a threshold that defines an uncharming extreme (which we hypothesize is identical to autism) containing 0.2% of the total population. In this illustration, that 0.2% comprises about one quarter with the wild type indicator and three quarters with the enhanced sensitivity indicator Charm Could Involve Brain Systems that Detect and Respond to Weaning Attempts To prevent ovulation, a baby must thwart maternal attempts to introduce other foods, reduce nighttime feedings, or reduce the frequency or total daily duration of sucklingeach of which increases the odds of ovulation (Stern et al 1986;Taylor et al 1999;World Health Organization 1998). Charm might enable a baby to detect initial weaning attempts (e.g., slower responses to feeding requests and less maternal smiling) and respond with special efforts to convince its mother to remain close and responsive to breast-feeding requests.…”

Section: Some Infant Social Behaviors Could Have Evolved As Fitness Imentioning

confidence: 99%

“…If so, then the ability should vary greatly among infants, should correlate with underlying fitness, and should influence parental resource allocation. Moreover, if social interaction ability encourages mothers to nurse in the pattern that inhibits ovulation, then detailed recordings of suckling (Taylor et al 1999) should show that high social interaction ability is associated with frequent suckling, greater total daily duration of suckling, and nighttime suckling-all of which inhibit ovulation.…”

Section: Indicator Quality Affects Parental Resource Allocationmentioning

confidence: 99%

Autism as the Low-Fitness Extreme of a Parentally Selected Fitness Indicator

Shaner

Miller²,

Mintz

2008

Hum Nat

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Siblings compete for parental care and feeding, while parents must allocate scarce resources to those offspring most likely to survive and reproduce. This could cause offspring to evolve traits that advertise health, and thereby attract parental resources. For example, experimental evidence suggests that bright orange filaments covering the heads of North American coot chicks may have evolved for this fitness-advertising purpose. Could any human mental disorders be the equivalent of dull filaments in coot chicks-low-fitness extremes of mental abilities that evolved as fitness indicators? One possibility is autism. Suppose that the ability of very young children to charm their parents evolved as a parentally selected fitness indicator. Young children would vary greatly in their ability to charm parents, that variation would correlate with underlying fitness, and autism could be the low-fitness extreme of this variation. This view explains many seemingly disparate facts about autism and leads to some surprising and testable predictions.

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“…Although it is not the only factor influencing fertihty, extended breastfeeding tends to increase birth intervals and decrease fertility through lactational amenorrhea (Dewey et al 1997;Rosetta 1989;Short et al 1991;Taylor et al 1999;Tracer 1996;Vitzthum 1989). However, the common assumption that in preindustrial populations any shift towards agriculture was accompanied by an increased availability of starchy weaning foods and led to the erosion of exclusive, predominant, and prolonged breastfeeding and shortened birth intervals must be questioned in light of these results.…”

Section: Relationships Between Weaning and Demographymentioning

confidence: 99%

Relationship between subsistence and age at weaning in “preindustrial” societies

Sellen

Smay

2001

Hum Nat

154

121

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Cross-cultural studies have revealed broad quantitative associations between subsistence practice and demographic parameters for preindustrial populations. One explanation is that variationin the availability of suitable weaning foods influenced the frequency and duration of breastfeeding and thus the length of interbirth intervals and the probability of child survival (the "weaning food availability" hypothesis). We examine the available data on weaning age variation in preindustrial populations and report results of a cross-cultural test of the predictions that weaning occurred earlier in agricultural and pastoral populations because dairy and cereal production increased the availability of easily digestible, nutrientrich foods appropriate for weaning. We found that, contrary to predictions, supplementation with liquid foods other than breast milk was delayed in agricultural populations relative to less agriculturally dependent ones and complementary feeding with solid foods was delayed in pastoral populations relative to those less dependent on herding. Although the duration of breastfeeding was longer in populations dependent on hunting, there was no qualitative evidence that such populations lacked foods appropriate for weaning. The patterns observed suggest that the relationships between demography and subsistence observed among preindustrial societies cannot be explained by the "weaning food availability" hypothesis. We discuss the implications for understanding the mechanisms underlying prehistoric human demography, subsistence shifts, allocation to parenting and mating effort, and the evolutionary implications of tradeoffs between diet and disease.

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Continuously Recorded Suckling Behaviour and Its Effect on Lactational Amenorrhoea

Cited by 21 publications

References 19 publications

Transfers and transitions: Parent–offspring conflict, genomic imprinting, and the evolution of human life history

Transfers and transitions: Parent–offspring conflict, genomic imprinting, and the evolution of human life history

Autism as the Low-Fitness Extreme of a Parentally Selected Fitness Indicator

Relationship between subsistence and age at weaning in “preindustrial” societies

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