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In choosing how many offspring to rear per cycle, parents commonly starts with more than they really can afford, then allow/encourage some to die. Multiple incentives for overproduction exist. By creating marginal young, parents may: (1) capitalize when unpredictable resources prove unusually rich; (2) supply these as food or servants for core brood(More)
Human mothers an efficient screening system to eliminate genetically abnormal embryos. However, the incidence of certain birth defects - most notably Down's syndrome - rises with maternal age. Conventional eplanations have focused on a rising production of defective zygotes; in contrast, an evolutionary approach suggest a relaxed maternal screen. Relaxed(More)
Avian brood reduction is widely viewed as a potential source of parent-offspring conflict. Yet empirical evidence belies the existence of conflict; for example, parents create the initial competitive asymmetries that facilitate brood reduction and, in fratricidal species, rarely intervene to stop sibling aggression. Here I examine parent-offspring conflict(More)
The theory of parent-offspring conflict (POC) provides a plausible evolutionary foundation for the dissonant behavioral interactions commonly observed between adults and their progeny. It has been modelled extensively, but its predictions for phenotypes are murky and have been subjected to scant empirical testing. The least ambiguous cases are likely to(More)
Previous studies of food allocation among nestlings of siblicidal birds have focussed on the proximate link between food and aggression. However, food sharing among sibs (and brood reduction) need not involve aggression. Here I examine the role of hunger (defined operationally in terms of the amount of food eaten recently) within the broader framework of(More)