Male body size, dominance rank and strategic use of aggression in a group-living mammal

Wright, Edward; Galbany, Jordi; McFarlin, Shannon C.; Ndayishimiye, Eric; Stoinski, Tara S.; Robbins, Martha M.

doi:10.1016/j.anbehav.2019.03.011

Cited by 54 publications

(74 citation statements)

References 72 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The study was conducted on 34 adult females monitored by the Dian Fossey Gorilla Fund's Karisoke Research Center, Volcanoes National Park, Rwanda (between 1˚21'and 1˚35'S and 29˚22 and 29˚44'E). We collected body size measurements between January 2014 and July 2016 using the non-invasive parallel laser method [60][61][62][63][64]. We measured two linear body dimensions, back breadth and body length as described in Wright et al [64] and Galbany et al [62,63].…”

Section: Study Population and Photogrammetrymentioning

confidence: 99%

“…We collected body size measurements between January 2014 and July 2016 using the non-invasive parallel laser method [60][61][62][63][64]. We measured two linear body dimensions, back breadth and body length as described in Wright et al [64] and Galbany et al [62,63]. These two measures incorporate several components of body size such as skeletal dimensions, and overlying tissue, including the rounded contours of the deltoid and gluteal muscles.…”

Section: Study Population and Photogrammetrymentioning

confidence: 99%

“…In this study we examined the interrelationships among adult female body size, dominance rank, and two measures of reproductive success, inter-birth interval and infant mortality, in wild mountain gorillas. Using the non-invasive parallel laser method [60][61][62][63][64] we measured two linear body dimensions associated with body size, back breadth and body length. We then tested the hypothesis that both morphological traits positively correlate with female dominance rank.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Dominance rank but not body size influences female reproductive success in mountain gorillas

et al. 2020

Self Cite

View full text Add to dashboard Cite

According to life history theory, natural selection has shaped trade-offs for allocating energy among growth, reproduction and maintenance to maximize individual fitness. In social mammals body size and dominance rank are two key variables believed to influence female reproductive success. However, few studies have examined these variables together, particularly in long-lived species. Previous studies found that female dominance rank correlates with reproductive success in mountain gorillas (Gorilla beringei beringei), which is surprising given they have weak dominance relationships and experience seemingly low levels of feeding competition. It is not currently known whether this relationship is primarily driven by a positive correlation between rank and body size. We used the non-invasive parallel laser method to measure two body size variables (back breadth and body length) of 34 wild adult female mountain gorillas, together with long-term dominance and demography data to investigate the interrelationships among body size, dominance rank and two measures of female reproductive success (inter-birth interval N = 29 and infant mortality N = 64). Using linear mixed models, we found no support for body size to be significantly correlated with dominance rank or female reproductive success. Higher-ranking females had significantly shorter inter-birth intervals than lower-ranking ones, but dominance rank was not significantly correlated with infant mortality. Our results suggest that female dominance rank is primarily determined by factors other than linear body dimensions and that high rank provides benefits even in species with weak dominance relationships and abundant year-round food resources. Future studies should focus on the mechanisms behind heterogeneity in female body size in relation to trade-offs in allocating energy to growth, maintenance and lifetime reproductive success.

show abstract

Section: Study Population and Photogrammetrymentioning

confidence: 99%

Section: Study Population and Photogrammetrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Dominance rank but not body size influences female reproductive success in mountain gorillas

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…Variation in male strength and male-male contest competition is expected over different phases of the male dominance tenure, with males predicted to be more vulnerable to competitors when they are not fully grown and are less experienced in the early phase of their tenure or when they passed their prime and have lower competitive ability (Steenbeek 2000;Alberts 2012). Male strength and competitive ability may correlate negatively with age and are likely to vary among males of the same age, because other factors may also play a role such as body size, physical condition, experience, personality, and skills (Plavcan and van Schaik 1997;Arnott and Elwood 2009;Wright et al 2019). The optimal female reproductive strategy may therefore involve a trade-off between dispersal costs, such as time lost for reproduction, versus the benefits of choosing better protective male (Robbins et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Intersexual conflict influences female reproductive success in a female-dispersing primate

Manguette

Robbins

Breuer

et al. 2019

Behav Ecol Sociobiol

Self Cite

View full text Add to dashboard Cite

In group-living mammals, individual efforts to maximize reproductive success result in conflicts and compromises between the sexes. Females utilize counterstrategies to minimize the costs of sexual coercion by males, but few studies have examined the effect of such behaviors on female reproductive success. Secondary dispersal by females is rare among group-living mammals, but in western gorillas, it is believed to be a mate choice strategy to minimize infanticide risk and infant mortality. Previous research suggested that females choose males that are good protectors. However, how much female reproductive success varies depending on male competitive ability and whether female secondary dispersal leads to reproductive costs or benefits has not been examined. We used data on 100 females and 229 infants in 36 breeding groups from a 20-year long-term study of wild western lowland gorillas to investigate whether male tenure duration and female transfer rate had an effect on interbirth interval, female birth rates, and offspring mortality. We found that offspring mortality was higher near the end of males' tenures, even after excluding potential infanticide when those males died, suggesting that females suffer a reproductive cost by being with males nearing the end of their tenures. Females experience a delay in breeding when they dispersed, having a notable effect on birth rates of surviving offspring per female if females transfer multiple times in their lives. This study exemplifies that female counterstrategies to mitigate the effects of male-male competition and sexual coercion may not be sufficient to overcome the negative consequences of male behavior. Significance Individual reproductive success is maximized through conflicts and compromises between the sexes in social mammals. In species with high dimorphism, females can experience sexual coercion by males and develop counterstrategies to reduce these costs. We studied this link in western lowland gorillas, which exhibit female secondary dispersal, a strategy that is believed to reflect female choice for the protective abilities of males. We found that females are faced with the dilemma of staying with a silverback at the end of his tenure and risk higher infant mortality versus dispersing and suffering reproductive delays and lower Communicated by M. A. van Noordwijk Electronic supplementary material The online version of this article (

show abstract

“…Decades of work has demonstrated various correlates with dominance rank or status within a social group. For example in many species, the social ranks of adults are well predicted by certain phenotypes such as body size or physical markings, or certain conventions such as age or tenure [7–12]. Social factors, such as support from conspecifics or presence of kin, also influence dominance rank [5,13–15].…”

Section: Introductionmentioning

confidence: 99%

Juvenile rank acquisition influences fitness independent of adult rank

Strauss

Shizuka

Holekamp

2019

Preprint

View full text Add to dashboard Cite

17Social rank has been identified as a significant determinant of fitness in a variety of 18 species. The importance of social rank suggests that the process by which juveniles come to 19 establish their position in the social hierarchy is a critical component of social development. 20Here, we use the highly predictable process of rank acquisition in spotted hyenas to study the 21 consequences of variation in rank acquisition in early life. In spotted hyenas, rank is 'inherited' 22 through a learning process called 'maternal rank inheritance.' This pattern is highly predictable: 23 ~80% of juveniles acquire the exact rank predicted by the rules of maternal rank inheritance. 24This predictable nature of rank acquisition in these societies allows the process of rank 25 acquisition to be studied independently from the ultimate rank that each juvenile attains. In this 26 study, we use a novel application of the Elo-rating method to calculate each juvenile's deviation 27 from expected pattern of maternal rank inheritance during development. Despite variability in 28 rank acquisition in juveniles, most of these juveniles come to attain the exact rank expected of 29 them according to the rules of maternal rank inheritance. Nevertheless, we find that transient 30 variation in rank acquisition in early life predicts long term fitness consequences for these 31 individuals: juveniles 'underperforming' their expected ranks show reduced survival and lower 32 lifetime reproductive success than better-performing peers. Finally, we present evidence that 33 this variability in rank acquisition in early life represents a source of early life adversity, and that 34 multiple sources of early life adversity have cumulative, but not compounding, effects on fitness. 36risk, cooperative breeding, and cooperative resource defense, are weighed against costs such 40 as increased competition over local resources, pathogen transmission, and risk of social 41 conflict. These costs and benefits may not be experienced by all group members equally; some 42 individuals gain more of the benefits and suffer fewer of the costs than others [1,2]. In many 43 animal societies, this disparity among group-mates is reflected by a dominance hierarchy, 44where individuals differ systematically in their tendency to display subordinate signals to their 45 group-mates [3]. A useful abstraction of the network of complex and unequal relationships 46 among group members is 'rank,' which describes the extent to which an individual is able to 47 exert power over its group-mates. Extensive research from a variety of organisms has 48 demonstrated that individuals of high rank, which are able to exert power over most other 49 individuals in their social group, enjoy dramatic advantages as a result of their position in the 50 social hierarchy, although species vary in the nature and strength of the relationship between 51 social status and fitness [2,4-6]. 52Decades of work has demonstrated various correlates with dominance rank or status 53 within a social group. For ...

show abstract

Male body size, dominance rank and strategic use of aggression in a group-living mammal

Cited by 54 publications

References 72 publications

Dominance rank but not body size influences female reproductive success in mountain gorillas

Dominance rank but not body size influences female reproductive success in mountain gorillas

Intersexual conflict influences female reproductive success in a female-dispersing primate

Juvenile rank acquisition influences fitness independent of adult rank

Contact Info

Product

Resources

About