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Male Aggression (male + aggression)
Selected AbstractsBook review: Sexual Coercion in Primates and Humans: An Evolutionary Perspective on Male Aggression Against FemalesAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 2 2010Joseph A. Camilleri No abstract is available for this article. [source] Operational sex ratio, sexual conflict and the intensity of sexual selectionECOLOGY LETTERS, Issue 5 2008Patrick S. Fitze Abstract Modern sexual selection theory indicates that reproductive costs rather than the operational sex ratio predict the intensity of sexual selection. We investigated sexual selection in the polygynandrous common lizard Lacerta vivipara. This species shows male aggression, causing high mating costs for females when adult sex ratios (ASR) are male-biased. We manipulated ASR in 12 experimental populations and quantified the intensity of sexual selection based on the relationship between reproductive success and body size. In sharp contrast to classical sexual selection theory predictions, positive directional sexual selection on male size was stronger and positive directional selection on female size weaker in female-biased populations than in male-biased populations. Thus, consistent with modern theory, directional sexual selection on male size was weaker in populations with higher female mating costs. This suggests that the costs of breeding, but not the operational sex ratio, correctly predicted the strength of sexual selection. [source] The Association Between Male Offspring Aggression and Paternal and Maternal Behavior of Peromyscus MiceETHOLOGY, Issue 10 2003Janet K. Bester-Meredith Parents influence offspring aggression through genetic and non-genetic mechanisms, although the latter are less well understood. To examine potential non-genetic effects of parents on offspring, we cross-fostered the highly aggressive and biparental California mouse (Peromyscus californicus) and the less aggressive, less parental white-footed mouse (Peromyscus leucopus). In-fostered animals within each species were used as controls. We examined associations between the foster parents' behavior and aggression of the fostered male offspring in resident,intruder (R,I) and neutral arena aggression tests. When both species and fostering groups were combined, R,I aggression of offspring was positively associated with paternal time spent retrieving pups. In contrast, aggression in a neutral arena was negatively associated with a composite score of maternal behavior. We discuss how our findings regarding paternal retrievals may explain previously reported effects of cross-fostering on male aggression. [source] Sex-Specific Aggression and Antipredator Behaviour in Young Brown TroutETHOLOGY, Issue 7 2001Jörgen I. Johnsson Sex differences in adult behaviour are often interpreted as consequences of sexual selection and/or different reproductive roles in males and females. Sex-specific juvenile behaviour, however, has received less attention. Adult brown trout males are more aggressive than females during spawning and juvenile aggression may be genetically correlated with adult aggression in fish. We therefore tested the prediction that immature brown trout males are more aggressive and bolder than immature females. Because previous work has suggested that precocious maturation increases dominance in salmonids, we included precocious males in the study to test the prediction that early sexual maturation increase male aggression and boldness. Aggression and dominance relations were estimated in dyadic contests, whereas boldness was measured as a response to simulated predation risk using a model heron. Independent of maturity state, males initiated more than twice as many agonistic interactions as females in intersexual contests. However, males were not significantly more likely to win these contests than females. The response to a first predator attack did not differ between sex categories, but males reacted less to a second predator attack than females. Sexual maturity did not affect the antipredator response in males. Since there is no evidence from field studies that stream-living immature male and female salmonids differ in growth rate, it appears unlikely that the sex differences demonstrated are behavioural consequences of sex-specific investment in growth. It seems more likely that sex-specific behaviour arises as a correlated response to sexually selected gene actions promoting differential behaviour in adult males and females during reproduction. Alternatively, sex differences may develop gradually during juvenile life, because a gradual developmental program should be less costly than a sudden behavioural change at the onset of sexual maturity. [source] The Perils of the Back Seat: Date Rape, Race and Gender in 1950s AmericaGENDER & HISTORY, Issue 1 2008Lisa Lindquist Dorr Dating among white American teenagers in the 1950s caused parents considerable concern, as it represented disturbing developments in sexual expectations. While the rhetoric surrounding marriage celebrated traditional gender roles and monogamy, Americans bemoaned social and moral decay, caused in part by women's encroachment on male prerogatives. Sexual experience for boys increasingly became a defining gender characteristic and a means of achieving manhood as well. Ideas about proper marital norms and studies of dating practices among young people naturalised male aggression as proof of masculinity, which made girls, even ,respectable ones', vulnerable to violence from their dates. As teens' acceptance of going steady became more widespread, older racialised narratives of sexual danger evolved to incorporate new dating trends. Whereas American, and especially southern white, women knew the dangers of the supposed ,black beast rapist', they learnt during the 1950s that a special danger could confront them in the back seat of cars, despite the presence of their white, male date. Even with a white protector, white women remained vulnerable to violence on dates, whether from black men or from their white date. As dating conventions loosened, white women found that that the perils of the back seat only increased. [source] Male,male combats in a polymorphic lizard: residency and size, but not color, affect fighting rules and contest outcomeAGGRESSIVE BEHAVIOR, Issue 3 2009Roberto Sacchi Abstract Theoretical models predict that the outcome of dyadic agonistic encounters between males is influenced by resource-holding potential, resource value, and intrinsic aggressiveness of contestants. Moreover, in territorial disputes residents enjoy a further obvious competitive advantage from the residency itself, owing to the intimate familiarity with their territory. Costs of physical combats are, however, dramatically high in many instances. Thus, signals reliably reflecting fighting ability of the opponents could easily evolve in order to reduce these costs. For example, variation in color morph in polymorphic species has been associated with dominance in several case studies. In this study, we staged asymmetric resident-intruder encounters in males of the common wall lizard Podarcis muralis, a species showing three discrete morphs (white, yellow, and red) to investigate the effects of asymmetries in color morph, residency, and size between contestants on the outcome of territorial contests. We collected aggression data by presenting each resident male with three intruders of different color morph, in three consecutive tests conducted in different days, and videotaping their interactions. The results showed that simple rules such as residency and body size differences could determine the outcome of agonistic interactions: residents were more aggressive than intruders, and larger males were competitively superior to smaller males. However, we did not find any effect of color on male aggression or fighting success, suggesting that color polymorphism in this species is not a signal of status or fighting ability in intermale conflicts. Aggr. Behav. 35:274,283, 2009. © 2009 Wiley-Liss, Inc. [source] Stepping up the pressure: arousal can be associated with a reduction in male aggressionAGGRESSIVE BEHAVIOR, Issue 6 2008Andrew Ward Abstract The attentional myopia model of behavioral control [Mann and Ward, 2007] was tested in an experiment investigating the relationship between physiological arousal and aggression. Drawing on previous work linking arousal and narrowed attentional focus, the model predicts that arousal will lead to behavior that is relatively disinhibited in situations in which promoting pressures to aggress are highly salient. In situations in which inhibitory pressures are more salient, the model predicts behavior that is relatively restrained. In the experiment, 81 male undergraduates delivered noise-blasts against a provoking confederate while experiencing either high or low levels of physiological arousal and, at the same time, being exposed to cues that served either to promote or inhibit aggression. In addition to supporting the predictions of the model, this experiment provided some of the first evidence for enhanced control of aggression under conditions of heightened physiological arousal. Implications for interventions designed to reduce aggression are discussed. Aggr. Behav. 34:584,592, 2008. © 2008 Wiley-Liss, Inc. [source] Ontogeny and sexual dimorphism in booted macaques (Macaca ochreata)JOURNAL OF ZOOLOGY, Issue 1 2005Michael A. Schillaci Abstract Ontogeny and sexual dimorphism have been important topics of investigation among researchers interested in the life history and ecology of non-human primates. It has been suggested that sex differences in the duration of growth are primarily, but not entirely, responsible for the sexual dimorphism observed in primate species with multimale,multifemale social structure, such as that seen in macaque monkeys (subfamily Cercopithecinae). Sexual dimorphism and growth was investigated in a wild population of booted macaques Macaca ochreata from Sulawesi, Indonesia. The results of our investigation suggest that the observed dimorphism in this population is primarily a product of greatly increased growth rates in dentally mature young adult males, in addition to prolonged male growth. This pattern of male growth may be an adaptive response to reduce the risk of adult male aggression before obligatory male emigration, and to facilitate competition for females soon after immigration into a new social group. [source] Relationship between sexual interactions and the timing of the fertile phase in captive female Japanese macaques (Macaca fuscata)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 10 2009Cécile Garcia Abstract Japanese macaques live in multi-male/multi-female social groups in which competition between males, female mate choice, and alternative male mating strategies are important determinants of mating and reproductive success. However, the extent to which adult males rely on female behavior to make their mating decisions as well as the effect of social rank on mating success are not clear as results are inconclusive, varying from study to study. In this study, we combined behavioral and endocrine data of 14 female Japanese macaques to examine the relationship between ovarian cycle phase and frequency of sexual behaviors, and to investigate how social rank influences sexual behavior in this species. We found that there was no increase in female proceptive behaviors during the fertile phase of the ovarian cycle, suggesting that female behaviors did not clearly signal the probability of conception. In spite of that, the frequencies of ejaculatory copulations were highest during this phase, indicating that the attractivity of females increased significantly during the period with higher probability of conception. Males, and especially the highest ranking male, were able to discriminate females nearing ovulation and to concentrate their mating effort, implying that the timing of ovulation was not concealed from them. The , male seemed able to monopolize most female matings, which is probably due in part to the low number of females simultaneously ovulating and to the limited number of inconspicuous places that the lower ranking males have to mate with females and avoid , male aggression. All together, these results suggest that different males may have access to different signals of ovulation and/or are differentially restrained as to how they can act on that information. The exact nature of the estrogen-related cues males use to recognize female reproductive status, and to what extent males use them warrants further investigation. Am. J. Primatol. 71:868,879, 2009. © 2009 Wiley-Liss, Inc. [source] The dangers of multi-male groupings: trauma and healing in cercopithecoid monkeys from CameroonAMERICAN JOURNAL OF PRIMATOLOGY, Issue 7 2009Tara J. Chapman Abstract This study examines the potential linkage between social organization and trauma in a sample of cercopithecids from Cameroon. Skeletal trauma is described in a museum collection of eight sympatric monkey species. Macroscopic analysis was carried out on a total of 139 complete skeletons of mangabeys, colobines and guenons. Species in multi-male groups were found to have higher fracture frequencies than those in uni-male groups. These higher frequencies may be related to intra-specific male,male aggression; however, similarities in fracture patterning between males and females in multi-male groups suggest that other factors may be involved. Although fracture etiology may not be identified with certainty, this study suggests that predation may indirectly be a cause of traumatic injuries in those species of cercopithecid monkeys displaying multi-male social organizations. The data presented also highlight the utility of museum collections as an additional resource in analyses of primate behavior, demonstrating that behavioral information does not die when the animal does. Am. J. Primatol. 71:567,573, 2009. © 2009 Wiley-Liss, Inc. [source] Sex differences in the social behavior of wild spider monkeys (Ateles geoffroyi yucatanensis)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 1 2009Kathy Y. Slater Abstract Competition for resources and the need for cooperation are reported to affect patterns of social interactions and thus the quality of social relationships in primates. Relationships may be described as high quality when both individuals behave in a way that benefits their partner. We investigated the distribution of a wide range of social behaviors across sex partner combinations of adult spider monkeys with specific reference to contested resources. Data were collected from two communities of wild spider monkeys (Ateles geoffroyi yucatanensis) in the Otoch Ma'ax Yetel Kooh reserve in Yucatan, Mexico. Affiliative behavior was exchanged most frequently between males, and as male,male aggression was rare, male,male social relationships were characterized as high quality. Female,female social relationships were best described as low quality as females showed no preference to be in proximity with other females and female,female affiliative behavior was rare. Relationships between the sexes generally were characterized by high rates of female-directed male aggression, although additional investigation into the effects of kinship and female reproductive state on male,female relationships is required before further conclusions can be drawn. Dyadic and coalitionary female,female aggression was significantly higher than expected in a feeding context, confirming that female spider monkeys primarily compete for access to food. Male,male aggression did not increase significantly when in the presence of females, but males embraced at higher rates when in mixed-sex subgroups. As embraces serve to reduce the likelihood of aggression during tense situations, high rates of male,male embraces in mixed-sex subgroups may mitigate male conflicts over access to females. Am. J. Primatol. 71:21,29, 2009. © 2008 Wiley-Liss, Inc. [source] Variation in fecal testosterone levels, inter-male aggression, dominance rank and age during mating and post-mating periods in wild adult male ring-tailed lemurs (Lemur catta)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 12 2007L. Gould Abstract In primate species exhibiting seasonal reproduction, patterns of testosterone excretion in adult males are variable: in some species, peaks correlate with female receptivity periods and heightened male,male aggression over access to estrous females, in others, neither heightened aggression nor marked elevations in testosterone have been noted. In this study, we examined mean fecal testosterone ( f,T) levels and intermale aggression in wild adult male ring-tailed lemurs residing in three groups at Beza Mahafaly Reserve, Madagascar. Results obtained from mating and post-mating season 2003 were compared to test Wingfield et al. [1990. Am Nat 136:829,846] "challenge hypothesis", which predicts a strong positive relationship between male testosterone levels and male,male competition for access to receptive females during breeding season. f,T levels and rates of intermale aggression were significantly higher during mating season compared to the post-mating period. Mean f,T levels and aggression rates were also higher in the first half of the mating season compared with the second half. Number of males in a group affected rates of intermale agonism, but not mean f,T levels. The highest-ranking males in two of the groups exhibited higher mean f,T levels than did lower-ranking males, and young males exhibited lower f,T levels compared to prime-aged and old males. In the post-mating period, mean male f,T levels did not differ between groups, nor were there rank or age effects. Thus, although male testosterone levels rose in relation to mating and heightened male,male aggression, f,T levels fell to baseline breeding levels shortly after the early mating period, and to baseline non-breeding levels immediately after mating season had ended, offsetting the high cost of maintaining both high testosterone and high levels of male,male aggression in the early breeding period. Am. J. Primatol. 69:1325,1339, 2007. © 2007 Wiley-Liss, Inc. [source] | ||||||||||