Book contents
- Frontmatter
- Contents
- List of contributors
- Foreword
- Preface
- Part I Reproductive skew theory
- Part II Testing assumptions and predictions of skew models
- 3 Reproductive skew in female-dominated mammalian societies
- 4 The effects of heterogeneous regimes on reproductive skew in eutherian mammals
- 5 Social skew as a measure of the costs and benefits of group living in marmots
- 6 Explaining variation in reproductive skew among male langurs: effects of future mating prospects and ecological factors
- 7 The causes and consequences of reproductive skew in male primates
- 8 Sociality and reproductive skew in horses and zebras
- 9 Reproductive skew in avian societies
- 10 Reproductive skew in cooperative fish groups: virtue and limitations of alternative modeling approaches
- 11 Reproductive skew in primitively eusocial wasps: how useful are current models?
- Part III Resolving reproductive conflicts: behavioral and physiological mechanisms
- Part IV Future directions
- Taxonomic index
- Subject index
4 - The effects of heterogeneous regimes on reproductive skew in eutherian mammals
from Part II - Testing assumptions and predictions of skew models
Published online by Cambridge University Press: 02 February 2010
- Frontmatter
- Contents
- List of contributors
- Foreword
- Preface
- Part I Reproductive skew theory
- Part II Testing assumptions and predictions of skew models
- 3 Reproductive skew in female-dominated mammalian societies
- 4 The effects of heterogeneous regimes on reproductive skew in eutherian mammals
- 5 Social skew as a measure of the costs and benefits of group living in marmots
- 6 Explaining variation in reproductive skew among male langurs: effects of future mating prospects and ecological factors
- 7 The causes and consequences of reproductive skew in male primates
- 8 Sociality and reproductive skew in horses and zebras
- 9 Reproductive skew in avian societies
- 10 Reproductive skew in cooperative fish groups: virtue and limitations of alternative modeling approaches
- 11 Reproductive skew in primitively eusocial wasps: how useful are current models?
- Part III Resolving reproductive conflicts: behavioral and physiological mechanisms
- Part IV Future directions
- Taxonomic index
- Subject index
Summary
Summary
Although several models of reproductive skew have been proposed, “transactional” models, on the one hand, and “tug-of-war” or “incomplete control” models, on the other hand, are most commonly debated. The former hold that dominants control group size by yielding “incentives” (a share of total group productivity) to subordinates, while the latter advance the idea that the dominant's control over one or more subordinates is incomplete. While high skew has been identified in several mammalian societies, most research on this topic shows that social mammals are likely to display intermediate, low, or variable reproductive skew. In an attempt to explain this pattern of results, the present chapter shows that mammals have evolved to cope with heterogeneous environmental regimes (abiotic and biotic), yielding a eutherian adaptive complex comprised of endothermy, relative brain enlargement, and behavioral flexibility. It is argued that these adaptations to environmental unpredictability favor the evolution of alternative phenotypes as well as situation and condition-dependent responses decreasing the likelihood that dominants will be able to monopolize subordinates, including females, and that high skew will be observed. Additional research is required to highlight similarities and, most important, differences in the routes to sociality between insects, birds, and mammals (see Vehrencamp 1979).
A simple mathematical model is presented linking reproductive suppression by a dominant to his/her influence on a subordinate and consequent ability to monopolize the subordinate. This treatment shows that, depending upon conditions, both types of skew models are realistic. Reproductive skew is discussed in relation to allocation decisions and the different reproductive tactics of female and male mammals.
- Type
- Chapter
- Information
- Reproductive Skew in VertebratesProximate and Ultimate Causes, pp. 84 - 113Publisher: Cambridge University PressPrint publication year: 2009
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