Feeding Competition and Agonistic Relationships Among Bwindi Gorilla beringei

Robbins, Martha M.

doi:10.1007/s10764-008-9275-4

Cited by 49 publications

(53 citation statements)

References 70 publications

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“…However, our study and other comparative studies of folivorous primates show considerable variation in hierarchical strength, both within and between species. Some of the variation in hierarchical expression may be explained by the percentage of contestable food items in their diet (Robbins, 2008). Although dominance characteristics in our study did not appear to be affected by habitat type or percentage of frugivory (results not shown), more subtle variation in quality or distribution of food items may affect dominance characteristics in groups of C. vellerosus.…”

Section: Conclusion Regarding the Effect Of Occasional Foraging On Ccontrasting

confidence: 59%

“…Furthermore, it is difficult to determine cut-off values for characterizing weakly versus highly expressed hierarchies. For example, Presbytis thomasi (Thomas langurs) show low aggression rates similar to species with weakly expressed hierarchies but high submission rates similar to species with highly expressed hierarchies (Sterck & Steenbeek, 1997) while the opposite is true for G. b. beringei (Robbins, 2008). Because species with stronger hierarchies do not always show higher agonistic rates than species with weaker hierarchies (de Waal & Luttrell, 1989;Sterck & Steenbeek, 1997), agonistic rates may not always be reliable indicators of hierarchical strength (Koenig, 2002;Koenig & Borries, 2006).…”

Section: Hierarchical Expressionmentioning

confidence: 99%

“…Many of these species occasionally forage on high-quality food items, which may only be available seasonally (reviewed in Snaith & Chapman, 2007). If these food items are contestable (i.e., it is possible to monopolize access to the food patch), it may be important to maintain decided dominance relationships year-round to avoid conflicts when highquality food items are available (Wrangham, 1980;Koenig et al, 1998;Archie et al, 2006;Robbins, 2008). Despite this growing body of evidence showing that folivores and herbivores form decided dominance relationships, few studies investigate how their dominance characteristics differ from those of frugivores that may experience more intense competition for food.…”

Section: Introductionmentioning

confidence: 99%

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Individualistic female dominance hierarchies with varying strength in a highly folivorous population of black-and-white colobus

Wikberg

Teichroeb²,

Iulia

et al. 2013

Behav

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Females that do not experience strong contest competition for food are presumed to form 'egalitarian' relationships (i.e., lacking strong, linear dominance hierarchies). However, recent studies of Gorilla beringei beringei (mountain gorilla) have documented relatively strong, linear female dominance hierarchies despite them having a highly folivorous diet that generates relatively low levels of within-group contest competition (Robbins et al., 2005(Robbins et al., , 2007. To investigate if this pattern holds true for other highly folivorous species that may experience low levels of contest competition, we examined the linearity and strength of female dominance hierarchies in a population of Colobus vellerosus (ursine colobus or white-thighed colobus) at Boabeng-Fiema, Ghana. From 2004 to 2011, we collected data via ad libitum and focal sampling of 75 adult and subadult females in eight groups. Half of the study groups had few unknown submissive relationships, and females formed individualistic hierarchies with high linearity indices ranging from 0.9 to 1. There was between-group variation in all components of hierarchical strength (i.e., hierarchical expression, consistency, and stability). Groups showed varying rates of submission, and there was a short latency to detect a linear hierarchy in some groups and a long latency in other groups (i.e., varying levels of hierarchical expression). Females in most groups formed unidirectional and stable relationships. Maturing females challenged older females in some groups, and these groups had more non-linear relationships (i.e., dyads with more submissive interactions down rather than up the hierarchy) and higher rates of individual rank change than other groups. Based on low rates of submission, long latencies, and/or some inconsistencies, we conclude that most groups form relatively

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Section: Conclusion Regarding the Effect Of Occasional Foraging On Ccontrasting

confidence: 59%

Section: Hierarchical Expressionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Individualistic female dominance hierarchies with varying strength in a highly folivorous population of black-and-white colobus

Wikberg

Teichroeb²,

Iulia

et al. 2013

Behav

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show abstract

“…Juvenile red howler monkeys were more likely to leave larger groups, but those results may reflect infanticide risks more than within-group scramble competition (Crockett and Pope 1993;Crockett and Janson 2000). One potential caveat for this study is that it focused on groups that have better habitat than the rest of the Virungas (McNeilage 1995) and have less reliance on contestable resources than other gorillas (Doran et al 2002;Robbins and McNeilage 2003;Robbins 2008a). Thus, our results may not be representative of other populations of mountain gorillas or of western lowland gorillas.…”

Section: Within-group Scramble Competitionmentioning

confidence: 98%

Socioecological influences on the dispersal of female mountain gorillas—evidence of a second folivore paradox

Robbins

Stoinski

Fawcett

et al. 2008

Behav Ecol Sociobiol

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Socioecological models indicate that the group structure and female dispersal patterns of primates are determined primarily by the abundance and distribution of food, predation pressures, and infanticide risks. In response to those influences, females of folivorous primates are considered relatively free to disperse into groups with the optimal size and structure. Yet some folivores live in small groups despite a potentially higher risk of predation, an apparent inconsistency known as the folivore paradox. This paper examines the female dispersal of a folivorous primate, the Virunga mountain gorillas. Mountain gorillas currently have no natural predators, but this species presents a different version of the folivore paradox: why do 50-60% of females reside in smaller one-male groups despite a higher risk of infanticide? In this study, females left one-male groups more frequently than multimale groups, but transfer destinations were not consistently biased toward multimale groups and those groups did not have higher immigration rates. We found no evidence of dispersal to avoid feeding competition within large groups, even as they have become three to five times larger than average. Thus, the lack of a consistent bias toward multimale groups was not because they are typically larger than one-male groups. Instead, the apparent inconsistencies may reflect limited female transfer opportunities, other influences on dispersal, and possibly an evolutionary disequilibrium in which current behavior does not optimize fitness.

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“…While female gorillas may not be able to avoid competitors as effectively, their diet might be thought to limit the intensity and potential benefits of feeding competition. However, in her study of mountain gorillas in the Bwindi Impenetrable National Park, Uganda, Robbins (2008) notes that when gorillas used fruit resources, it was typical for only some members of the group to climb into the fruit tree, effectively fissioning the group for foraging purposes. Fruit-feeding was associated with both scramble and contest competition among females.…”

mentioning

confidence: 99%