This article studies reproductive externalities within rural communities in poor countries. It is shown that such externalities create a link between household poverty, household size, and the local natural-resource base, each of which is viewed as being endogenous. The models presented here o!er an explanation for the fact that in recent decades large groups of people in various parts of the w...

In recent years, ethnographic research has challenged the notion within demography that fertility-related behaviour is the outcome of individualistic calculations of the costs and benefits of having children. Anthropology has further criticised the abstraction in demographic analysis of sexual behaviour and fertility decision-making from the socio-cultural and political context in which the ind...

Although alternative reproductive behaviours have been studied extensively, it has only been possible in a few cases to document the underlying life-history pathways and factors that determine their expression. In Symphodus ocellatus, a Mediterranean wrasse, males adopt a variety of behaviours. Within a season, they may invest in territory defence, nest building and broodcare (nesting males); j...

The dominant conceptual framework for understanding reproductive behaviour is highly individualistic. In this article, it is demonstrated that such a conceptualization is flawed, as behaviour is shaped by social relations and institutions. Using ethnographic evidence, the value of a social analysis of the local contexts of reproductive health is highlighted. A framework is set out for conductin...

Repeatable behavioural traits ('personality') have been shown to covary with fitness, but it remains poorly understood how such behaviour-fitness relationships come about. We applied a multivariate approach to reveal the mechanistic pathways by which variation in exploratory and aggressive behaviour is translated into variation in reproductive success in a natural population of blue tits, Cyani...

Studies across multiple organisms reveal considerable phenotypic variation in reproductive tactics. In some species, this variation is associated with maternal effects in which variation in maternal investment results in stable individual differences in reproductive function. Recent studies with the rat suggest that maternal effects can alter the function of neuroendocrine systems associated wi...

A key characteristic of eusocial species is reproductive division of labour. Honey bee colonies typically have a single reproductive queen and thousands of sterile workers. Adult queens differ dramatically from workers in anatomy, physiology, behaviour and lifespan. Young female workers can activate their ovaries and initiate egg laying; these 'reproductive' workers differ from sterile workers ...