Inclusive fitness for in-laws
- Dyble, M. ORCID Deparment of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
- Gardner, A. ORCID School of Biology, University of St Andrews, St Andrews KY16 9TH, UK
- Vinicius, L. ORCID Department of Anthropology, University College London, 14 Taviton Street, London WC1H 0BW, UK
- Migliano, A. B. ORCID Department of Anthropology, University of Zurich, Winterthurerstrasse, Zürich, Switzerland
- 2018-10-10
Published in:
- Biology Letters. - The Royal Society. - 2018, vol. 14, no. 10, p. 20180515
English
Cooperation among kin is common across the natural world and can be explained in terms of inclusive fitness theory, which holds that individuals can derive indirect fitness benefits from aiding genetically related individuals. However, human kinship includes not only genetic kin but also kin by marriage: our affines (in-laws) and spouses. Can cooperation between these genetically unrelated kin be reconciled with inclusive fitness theory? Here, we argue that although affinal kin and spouses do not necessarily share genetic ancestry, they may have shared genetic interests in future reproduction and, as such, can derive indirect fitness benefits though cooperating. We use standard inclusive fitness theory to derive a coefficient of shared reproductive interest (
s
) that predicts altruistic investment both in genetic kin and in spouses and affines. Specifically, a behaviour that reduces the fitness of the actor by
c
and increases the fitness of the recipient by
b
will be favoured by natural selection when
sb
>
c
. We suggest that the coefficient of shared reproductive interest may provide a valuable tool for understanding not only the evolution of human kinship but also cooperation and conflict across the natural world more generally.
Cooperation among kin is common across the natural world and can be explained in terms of inclusive fitness theory, which holds that individuals can derive indirect fitness benefits from aiding genetically related individuals. However, human kinship includes not only genetic kin but also kin by marriage: our affines (in-laws) and spouses. Can cooperation between these genetically unrelated kin be reconciled with inclusive fitness theory? Here, we argue that although affinal kin and spouses do not necessarily share genetic ancestry, they may have shared genetic interests in future reproduction and, as such, can derive indirect fitness benefits though cooperating. We use standard inclusive fitness theory to derive a coefficient of shared reproductive interest (
) that predicts altruistic investment both in genetic kin and in spouses and affines. Specifically, a behaviour that reduces the fitness of the actor by
and increases the fitness of the recipient by
will be favoured by natural selection when
>
. We suggest that the coefficient of shared reproductive interest may provide a valuable tool for understanding not only the evolution of human kinship but also cooperation and conflict across the natural world more generally.
- Language
-
- English
- Open access status
- hybrid
- Identifiers
-
- DOI 10.1098/rsbl.2018.0515
- ISSN 1744-9561
- Persistent URL
- https://sonar.ch/global/documents/69085
Statistics
Document views: 28
File downloads:
- Full-text: 0