Quality-quantity trade-off of human offspring under adverse environmental conditions.
A central paradigm in life-history theory is the trade-off between offspring number and quality. Several studies have investigated this trade-off in humans, but data are inconclusive, perhaps because prosperous socio-cultural factors mask the trade-off. Therefore, we studied 2461 offspring groups in an area under adverse conditions in northern Ghana with high fertility and mortality rates. In a linear mixed model controlling for differences in age and tribe of the mother and socioeconomic status, each additional child in the offspring group resulted in a 2.3% (95% CI 1.9-2.6%, P < 0.001) lower proportional survival of the offspring. Furthermore, we made use of the polygamous population structure and compared offspring of co-wives in 388 households, thus controlling for variation in resources between compounds. Here, offspring survival decreased 2.8% (95% CI 2.3-4.0%, P < 0.001) for each increase in offspring number. We interpret these data as an apparent quality-quantity trade-off in human offspring.
Meij
J J
JJ
Department of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, The Netherlands.
van Bodegom
D
D
Ziem
J B
JB
Amankwa
J
J
Polderman
A M
AM
Kirkwood
T B L
TB
de Craen
A J M
AJ
Zwaan
B J
BJ
Westendorp
R G J
RG
D000367:Age Factors; D001723:Birth Rate; D002648:Child; D046688:Child Mortality; D003710:Demography; D004777:Environment; D005869:Ghana; D006801:Humans; D007407:Interviews as Topic; D016014:Linear Models; D012044:Regression Analysis; D012959:Socioeconomic Factors