The demographic benefits of belligerence and bravery: defeated group repopulation or victorious group size expansion?

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Version: Final published version
Serval ID
serval:BIB_3AC4A2A4E7E1
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
The demographic benefits of belligerence and bravery: defeated group repopulation or victorious group size expansion?
Journal
PLoS One
Author(s)
Lehmann L.
ISSN
1932-6203 (Electronic)
ISSN-L
1932-6203 (Linking)
Publication state
Published
Issued date
2011
Volume
6
Number
7
Pages
e21437
Language
english
Abstract
Intraspecific coalitional aggression between groups of individuals is a widespread trait in the animal world. It occurs in invertebrates and vertebrates, and is prevalent in humans. What are the conditions under which coalitional aggression evolves in natural populations? In this article, I develop a mathematical model delineating conditions where natural selection can favor the coevolution of belligerence and bravery between small-scale societies. Belligerence increases an actor's group probability of trying to conquer another group and bravery increase the actors's group probability of defeating an attacked group. The model takes into account two different types of demographic scenarios that may lead to the coevolution of belligerence and bravery. Under the first, the fitness benefits driving the coevolution of belligerence and bravery come through the repopulation of defeated groups by fission of victorious ones. Under the second demographic scenario, the fitness benefits come through a temporary increase in the local carrying capacity of victorious groups, after transfer of resources from defeated groups to victorious ones. The analysis of the model suggests that the selective pressures on belligerence and bravery are stronger when defeated groups can be repopulated by victorious ones. The analysis also suggests that, depending on the shape of the contest success function, costly bravery can evolve in groups of any size.
Pubmed
Web of science
Open Access
Yes
Create date
16/06/2011 16:05
Last modification date
20/08/2019 13:30
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