Factors affecting outcome and intensity of intergroup encounters in crested macaques (Macaca nigra)

Martínez-Íñigo, Laura and Muhammad, Agil and Engelhardt, Antje and Pilot, Malgorzata and Majolo, Bonaventura (2017) Factors affecting outcome and intensity of intergroup encounters in crested macaques (Macaca nigra). In: 7th European Federation for Primatology Meeting, 21 - 25 August, 2017, Strasbourg, France.

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Item Type:Conference or Workshop contribution (Poster)
Item Status:Live Archive

Abstract

Intergroup encounters can have a substantial impact on individual fitness by altering access
to resources and increasing risk of injury and death. Numerical advantage is usually of para-
mount importance to maintain access to resources in between group contests. However, factors
affecting payoffs can also be involved in determining intergroup encounter outcome and inten-
sity. The most investigated so far has been location, often found to be relevant in explaining
contest result and level of aggression. Other factors, such as proportion of infants and female
reproductive state have yet to be thoroughly examined. Our aim was to investigate whether fe-
male reproductive state and proportion of infants, together with group size and location, played
a role in determining the outcome and intensity of intergroup encounters. We collected data for
9 consecutive months on 3 habituated groups of crested macaques ( Macaca nigra ) in the Tang-
koko Nature Reserve (North Sulawesi, Indonesia), yielding information on 163 intergroup en-
counters. Encounters tended to finish in a draw when groups were of similar sizes and both used
the location of the encounter with similar frequency. Odds of winning an encounter (i.e. displac-
ing the other group) were higher for those groups that used the encounter area more frequently
and had lower proportions of both fertile females and females with infants. The longer the en-
counter, the more likely it was to be aggressive, especially when group sizes were similar. Our
data support previous findings that location and group size play an important role in determin-
ing the nature and outcome of encounters. However, they suggest that intergroup encounters
are influenced by a broad range of factors that affect the competitive ability of groups. Our study
provides evidence that intergroup relationships in primates are more context dependent than
previously thought.

Keywords:between group contest competition, BGC, socioecology, primate
Subjects:C Biological Sciences > C100 Biology
C Biological Sciences > C990 Biological Sciences not elsewhere classified
C Biological Sciences > C120 Behavioural Biology
C Biological Sciences > C300 Zoology
C Biological Sciences > C180 Ecology
Divisions:College of Science > School of Life Sciences
College of Social Science > School of Psychology
Related URLs:
ID Code:30605
Deposited On:12 Mar 2018 11:26

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