1,720,966 research outputs found
Testing a Model of Coalition Formation in Two Macaque Species, Macaca sylvanus and Macaca assamensis
No full textTesting a Model of Coalition Formation in Two Macaque Species, Macaca sylvanus and Macaca assamensis
No full textSocioecology, but not cognition, predicts male coalitions across primates
No full textHumans form agonistic coalitions and alliances in many contexts, but this behavior is thought to be rare in other species. A prominent hypothesis states that coalitions may be under cognitive constraints, but this idea is debated and remains to be tested empirically. In this study, we evaluate the cognitive constraint hypothesis against 3 alternative hypotheses that stress the role of demography, substrate use, and resource competition, for the evolution of male coalitions. A comparative analysis of a unique data set of 86 multimale multifemale groups of 38 nonhuman primate species from all major radiations revealed no evolutionary association of male coalition frequency with cognitive capacity (as indexed by neocortex ratio and endocranial volume). The observed variation was best explained by demography and resource competition in that male coalitions were more likely to occur in species characterized by larger male groups and reduced levels of contest competition (after controlling for phylogeny). These findings suggest that constraints imposed by the socioecological setting, rather than cognition, explain best why some primate species evolved customary coalitionary behavior while others did not. This study presents the first empirical evidence against the long-standing view that cognitive abilities may impose a limit on the use of coalitions in animals
Mating skew in Barbary macaque males: the role of female mating synchrony, female behavior, and male–male coalitions
Full text linkA fundamental question of sexual selection
theory concerns the causes and consequences of reproductive
skew among males. The priority of access (PoA)
model (Altmann, Ann NY Acad Sci 102:338–435, 1962)
has been the most influential framework in primates living
in permanent, mixed-sex groups, but to date it has only
been tested with the appropriate data on female synchrony
in a handful of species. In this paper, we used mating data
from one large semi-free ranging group of Barbary
macaques: (1) to provide the first test of the priority-of-access model in this species, using mating data from 11
sexually active females (including six females that were
implanted with a hormonal contraceptive but who showed
levels of sexual activity comparable to those of naturally
cycling females) and (2) to determine the proximate
mechanism(s) underlying male mating skew. Our results
show that the fit of the observed distribution of matings
with sexually attractive females to predictions of the PoA
model was poor, with lower-ranking males mating more
than expected. While our work confirms that female
mating synchrony sets an upper limit to monopolization
by high-ranking individuals, other factors are also important.
Coalitionary activity was the main tactic used by males
to lower mating skew in the study group. Coalitions were
expressed in a strongly age-related fashion and allowed
subordinate, post-prime males to increase their mating
success by targeting more dominant, prime males. Conversely,
females, while mating promiscuously with several males during a given mating cycle, were more likely to initiate their consortships with prime males, thus reducing the overall effectiveness of coalitions. We conclude that
high-ranking Barbary macaque males have a limited ability to monopolize mating access, leading to a modest
mating skew among them
Age-dependent change of coalitionary strategy in male Barbary macaques
No full textInter- and intra-specific variation in the propensity to form coalitions has been explained by variation in the availability of suitable partners, distribution of fighting ability, coalition profitability, and costs of coordination. Male coalition formation can be an alternative reproductive strategy to one-on-one competition to maximize male reproductive success. Here we focus on age as a state variable to explain within-group variation in individual propensity to form coalitions against other group members. We specifically test the prediction that males conditionally switch from a solo strategy for achievement of high mating success to a cooperative strategy after reaching post-prime age in male Barbary macaques (Macaca sylvanus). We combined new observations with data collected in 2006 and 2008 on the same individuals from one captive group living in semi-natural conditions at Affenberg Salem, Germany, and found that in all years males between 5 and 13 years formed significantly fewer coalitions than males 14 years and older (post-prime). More importantly, we found those males that aged into the post-prime phase to have switched their reproductive strategy and to form significantly more coalitions in 2014 compared to 2008. These first longitudinal data together with earlier cross-sectional analyses in this and other primate species suggest that group-level measures of coalition propensity may be strongly affected by the age composition of groups and that male coalition formation can be a conditional reproductive strategy
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
