Fitness benefits of coalitionary aggression in male chimpanzees

Ian Gilby, Lauren J N Brent, Emily E. Wroblewski, Rebecca S. Rudicell, Beatrice H. Hahn, Jane Goodall, Anne E. Pusey

Research output: Contribution to journalArticle

110 Citations (Scopus)

Abstract

Coalitionary aggression occurs when at least two individuals jointly direct aggression at one or more conspecific targets. Scientists have long argued that this common form of cooperation has positive fitness consequences. Nevertheless, despite evidence that social bond strength (which is thought to promote coalition formation) is correlated with fitness in primates, cetaceans, and ungulates, few studies have directly examined whether coalitionary aggression improves reproductive success. We tested the hypothesis that among free-ranging chimpanzees (Pan troglodytes schweinfurthii), participation in coalitionary aggression increases reproductive output. Using 14 years of genetic and behavioral data from Gombe National Park, Tanzania, we found that coalitionary aggression increased a male's chances of (A) siring offspring, compared to other males of similar dominance rank, and (B) ascending in rank, a correlate of future reproductive output. Because male chimpanzees form coalitions with many others within a complex network, we used social network analysis to identify the types of connections correlated with these fitness benefits. The beneficiaries of coalitionary aggression were males with the highest "betweenness"-that is, those who tended to have coalition partners who themselves did not form coalitions with each other. This suggests that beyond simply recognizing third-party relationships, chimpanzees may use this knowledge to choose coalition partners. If so, this is a significant step forward in our knowledge of the adaptive value of social intelligence. Regardless of mechanism, however, this is the first evidence of genetic benefits of coalitionary aggression in this species, and therefore has important implications for understanding the evolution of cooperation.

Original languageEnglish (US)
Pages (from-to)373-381
Number of pages9
JournalBehavioral Ecology and Sociobiology
Volume67
Issue number3
DOIs
StatePublished - 2013
Externally publishedYes

Fingerprint

aggression
Pan troglodytes
fitness
reproductive performance
social networks
social benefit
cetacean
network analysis
social network
ungulate
ungulates
Tanzania
primate
dominance (genetics)
reproductive success
national parks
Primates
national park

Keywords

  • Chimpanzee
  • Coalition
  • Cooperation
  • Dominance rank
  • Paternity
  • Social bonds
  • Social network analysis

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Animal Science and Zoology

Cite this

Gilby, I., Brent, L. J. N., Wroblewski, E. E., Rudicell, R. S., Hahn, B. H., Goodall, J., & Pusey, A. E. (2013). Fitness benefits of coalitionary aggression in male chimpanzees. Behavioral Ecology and Sociobiology, 67(3), 373-381. https://doi.org/10.1007/s00265-012-1457-6

Fitness benefits of coalitionary aggression in male chimpanzees. / Gilby, Ian; Brent, Lauren J N; Wroblewski, Emily E.; Rudicell, Rebecca S.; Hahn, Beatrice H.; Goodall, Jane; Pusey, Anne E.

In: Behavioral Ecology and Sociobiology, Vol. 67, No. 3, 2013, p. 373-381.

Research output: Contribution to journalArticle

Gilby, I, Brent, LJN, Wroblewski, EE, Rudicell, RS, Hahn, BH, Goodall, J & Pusey, AE 2013, 'Fitness benefits of coalitionary aggression in male chimpanzees', Behavioral Ecology and Sociobiology, vol. 67, no. 3, pp. 373-381. https://doi.org/10.1007/s00265-012-1457-6
Gilby, Ian ; Brent, Lauren J N ; Wroblewski, Emily E. ; Rudicell, Rebecca S. ; Hahn, Beatrice H. ; Goodall, Jane ; Pusey, Anne E. / Fitness benefits of coalitionary aggression in male chimpanzees. In: Behavioral Ecology and Sociobiology. 2013 ; Vol. 67, No. 3. pp. 373-381.
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