Male Aggressive Behavior Research Articles

Stalk-eyed flies carrying a driving X chromosome compensate by increasing fight intensity

Exaggerated ornaments provide opportunities to understand how selection can operate at different levels to shape the evolution of a trait. While these features aid their bearer in attracting mates or fending off competitors, they can also be costly and influenced by the environment and genetic variation. The eyestalks of the stalk-eyed fly, Teleopsis dalmanni, are of interest because eyestalk length is the target of both intra- and intersexual selection and is also reduced by loci on a highly-divergent sex ratio X chromosome (XSR), a meiotic driver accounting for up to 30% of wild X chromosomes. Male stalk-eyed flies fight to control access to females and over food using a combination of low-intensity displays and high-intensity physical fights. We staged, filmed, and scored contests between pairs of eyespan-matched males to evaluate whether X chromosome type impacts the behavior and outcome of aggressive interactions. While our results broadly match expectations from previous studies, we found that XSR males used more high-intensity behaviors than males carrying a non-driving, standard X chromosome (XST), particularly when their eyestalks were of similar size or smaller than their opponents. Additionally, we found that when XSR males use high-intensity behaviors, they win more bouts than when they use low-intensity behaviors. Taken together, these results suggest that XSR impacts male aggressive behavior to compensate for the shorter eyestalks of XSR males and may help to explain how this selfish chromosome is maintained.

Male aggressive behaviors as an indicator in primate tourism management assessment

Primate tourism brings many benefits, but also some problems. How to better evaluate primate tourism is of significance for formulating tourism management strategies. In this study, we compared the aggressive behavior of three Sichuan snub-nosed monkey groups that encounter ecotourists and found that male aggressive behavior is a useful indicator for assessing ecotourism of these and, by inference, other groups. In high-risk tourism groups multiple monkeys direct aggression towards tourists, whereas low-risk tourism groups are characterized by low rates of such aggression. We found that tourists touching or attempting to touch the monkeys can trigger aggressive behaviors in all groups, while carrying food and eating have different effects across groups. In well-managed groups, tourist-directed aggressive behaviors are milder than in less well-managed groups. We propose that male monkey aggressive behavior elicited by tourists’ behavior is a useful indicator in assessing primate tourism, and can help guide further improvements in tourism management.

Time budget of a mallard duck population residing in an urban park in northern Portugal during courtship and nesting period

Behavioural observations were used to investigate the temporal dynamics events and associated variation in the daily activities of a sedentary population of mallard duck (Anas platyrhynchos) inhabiting an urban park in northern Portugal. Data was collected at Porto City Park from December to April, during the species’ courtship and early nesting periods. The most frequent activities for this population were locomotion, resting and feeding. Statistical analysis revealed that male and female behaviours differed significantly throughout the courtship period, as males exhibited more displays and aggressive behaviour while females were more prone to feed in order to meet their increased nutritional and energetic needs. Temporal analyses showed that courtship reached a peak in intensity in February, since it was in this month that the highest values for mating, aggressive behaviour in males and defensive behaviour in females were observed. Behavioural differences were found for this population, with higher feeding rates compared to those of wild populations as well as lower defensive behaviour rates. This paper sheds light on how synanthropized populations, as well as those from Southwestern Europe, show different behavioural responses from other populations. Additional extensive monitoring of population dynamics and factors such as latitudinal differences, habituation to humans and climate change will help to predict future growth and expansion rates.

Neural dynamics in the limbic system during male social behaviors

Sexual and aggressive behaviors are vital for species survival and individual reproductive success. Although many limbic regions have been found relevant to these behaviors, how social cues are represented across regions and how the network activity generates each behavior remains elusive. To answer these questions, we utilize multi-fiber photometry (MFP) to simultaneously record Ca2+ signals of estrogen receptor alpha (Esr1)-expressing cells from 13 limbic regions in male mice during mating and fighting. We find that conspecific sensory information and social action signals are widely distributed in the limbic system and can be decoded from the network activity. Cross-region correlation analysis reveals striking increases in the network functional connectivity during the social action initiation phase, whereas late copulation is accompanied by a "dissociated" network state. Based on the response patterns, we propose a mating-biased network (MBN) and an aggression-biased network (ABN) for mediating male sexual and aggressive behaviors, respectively.

MEDIA-HYPE CAUSING AGGRESSION IN YOUTH OF FAISALABAD: AN OPINION ANALYSIS

Aggressive behavior among adolescents was studied in this study in relation to watching of television. Information was collected through a survey (α= 0.37), from 300 males and females from different universities in Faisalabad. They were asked how long they watch TV (in hours) in a day and for which purpose they watch TV. In the last section of the questionnaire, they were questioned to measure the nature of their aggressive behavior, how much they i) get angered ii) feel disappointed iii) Use rude language iv) feel insecure v) feel captured (α= 0.32). The results show that TV watching time and the purpose of watching TV are not significantly / insignificantly associated with aggressive behavior. The point about the purpose for which young people watch TV the most, this data shows that most people watch TV for information. Males who use the TV for other purposes have more aggressive behavior than others. In the case of females, aggression in behavior didn’t affect differently with the different use of TV. Intensity of TV use (how many hours TV watched in a day) was positively and insignificantly associated with aggressive behavior in males but in females no relation was found. Keywords: aggressive behavior, television, intensity of TV viewing, TV hype.

Effect of male–female relatedness on aggression and inbreeding in an egg parasitoid wasp

Aggressive behavior is important for acquiring crucial resources in many animals. As such behavior is costly, selection favors contestants that can accurately gather information regarding the likely costs and benefits of conflict to enable appropriate tactical decisions. Mate choice based on relatedness is widespread among animals and has severe consequences. Theoretically, due to the potential costs of inbreeding, contestants may benefit from discriminating between relative and nonrelative mates and adjusting their behavior accordingly. If inbreeding results in fitness costs, related mates might be perceived as less valuable and individuals might be expected to invest less in costly aggression, and vice versa. However, the role of male–female relatedness in aggression has been less addressed. The egg parasitoid wasp Anastatus disparis, which exhibits extreme male–male aggressive behavior for mating opportunities, was used as an experimental model to explore the role of male–female relatedness in aggression. Inconsistent with our prediction, male–female relatedness had no significant effect on male–male fighting frequency or intensity in A. disparis. The ability of males to discriminate relative from nonrelative females is a prerequisite for male–female relatedness to affect males’ aggression. However, A. disparis males did not exhibit any mating preferences for relative or nonrelative females. Besides, inbreeding did not result in depression in terms of longevity, fecundity or sex ratio in A. disparis. Our finding of no effect of male–female relatedness on male–male fights in A. disparis may be caused by a lack of kin discrimination ability or/and a lack of benefits from discriminating relatives from nonrelatives.

The effects of Ginger (Zingiber officinale) roots on the reproductive aspects in male Japanese Quails (Coturnix coturnix japonica)

BackgroundThe Japanese quail is considered one of the most significant species in the poultry industry. However, the high male-to-female ratio results in the aggressive behavior of males. Dietary strategies that improve the properties of semen could reduce the number of males required to maintain optimal fertility and reduce aggressive behavior. Therefore, this study aims to provide insight into the possible improving efm fect of ginger roots on the reproductive aspects of Japanese male quails.ResultsTo achieve this objective, powder of Ginger roots was administrated to 2 groups of quails (10, and 15 g/Kg feed) from 7 days until 70 days of age. Some males were reared singly in cages (n = 40 for each group) to assess sperm quality and other males (n = 32 for each group) were raised with females to assess fertility and sperm-egg penetration. Additionally, biochemical tests and histological examination were also performed. When compared to the control group, dietary inclusion of Ginger at a dose of 15 g caused more improvement in ejaculate volume, sperm concentration, motility, viability and sperm-egg penetration. Whereas, the motility and fertility percentages of sperms were equipotent in both doses. Dose-dependent increases were found in the cloacal gland area and volume, as well as foam production and weight. Both doses resulted in a significant reduction in plasma total cholesterol along with an elevation cin plasma testosterone and lipid peroxides. The comparison between all groups concerning nitric oxide, catalase, superoxide dismutase, and total antioxidant capacity revealed the absence of significant difference. Morphologically, the diameter of the seminiferous tubules and the height of germinal epithelium significantly increased especially in the higher dose of Ginger.ConclusionsGinger roots especially at a dose of 15 gm/kg feed was effective in improving male reproductive performance. These findings are of utmost importance in encouraging the addition of Ginger roots in ration formulation in male quails.

Early life stressful experiences escalate aggressive behavior in adulthood via changes in transthyretin expression and function

Escalated and inappropriate levels of aggressive behavior referred to as pathological in psychiatry can lead to violent outcomes with detrimental impact on health and society. Early life stressful experiences might increase the risk of developing pathological aggressive behavior in adulthood, though molecular mechanisms remain elusive. Here, we provide prefrontal cortex and hypothalamus specific transcriptome profiles of peripubertal stress (PPS) exposed Balb/c adult male mice exhibiting escalated aggression and adult female mice resilient to such aberrant behavioral responses. We identify transthyretin (TTR), a well known thyroid hormone transporter, as a key regulator of PPS induced escalated aggressive behavior in males. Brain-region-specific long-term changes in Ttr gene expression and thyroid hormone (TH) availability were evident in PPS induced escalated aggressive male mice, circulating TH being unaltered. Ttr promoter methylation marks were also altered being hypermethylated in hypothalamus and hypomethylated in prefrontal cortex corroborating with its expression pattern. Further, Ttr knockdown in hypothalamus resulted in escalated aggressive behavior in males without PPS and also reduced TH levels and expression of TH-responsive genes (Nrgn, Trh, and Hr). Escalated aggressive behavior along with reduced Ttr gene expression and TH levels in hypothalamus was also evident in next generation F1 male progenies. Our findings reveal that stressful experiences during puberty might trigger lasting escalated aggression by modulating TTR expression in brain. TTR can serve as a potential target in reversal of escalated aggression and related psychopathologies.

The doublesex gene regulates dimorphic sexual and aggressive behaviors in Drosophila

Most animal species display dimorphic sexual behaviors and male-biased aggressiveness. Current models have focused on the male-specific product from the fruitless (fruM) gene, which controls male courtship and male-specific aggression patterns in fruit flies, and describe a male-specific mechanism underlying sexually dimorphic behaviors. Here we show that the doublesex (dsx) gene, which expresses male-specific DsxM and female-specific DsxF transcription factors, functions in the nervous system to control both male and female sexual and aggressive behaviors. We find that Dsx is not only required in central brain neurons for male and female sexual behaviors, but also functions in approximately eight pairs of male-specific neurons to promote male aggressiveness and approximately two pairs of female-specific neurons to inhibit female aggressiveness. DsxF knockdown females fight more frequently, even with males. Our findings reveal crucial roles of dsx, which is broadly conserved from worms to humans, in a small number of neurons in both sexes to establish dimorphic sexual and aggressive behaviors.

An Examination of a Modified START NOW Dialectical Behavior Therapy-Based Intervention and a Behavioral Level System on Male Inmate Misbehavior, Aggressive Behavior, and Suicide Precaution Status

This study employed a quasi-experimental design to evaluate the impact of a modified START NOW program + behavioral level system (BLS) in a self-contained therapeutic community (SCTC) on inmate misbehavior at a correctional facility. The SCTC included a modified START NOW manualized mental health treatment, recreation groups, process groups as needed, and a level system on which to base the attainment of privileges. Inmate data was evaluated at 3-months pre- and post-SCTC to determine if there were differences in the number of mental health referrals for misbehavior, referrals to the restrictive housing unit, write-ups, instances of spontaneous use of force by correctional officers, and placement on suicide precaution status compared with a control group of inmates who were placed in restrictive housing during the same time frame. Analyses examined differences between these two groups comparing variables from pre-intervention to post-intervention timepoints. Both the modified START NOW + behavioral intervention group and the control group improved significantly from pre-to-post intervention on the number of placements in restrictive housing and number of write-ups for misbehavior but did not significantly improve on the remaining outcome measures. Study strengths and limitations are discussed.

Behavioral features in Williams Beuren syndrome: A Tunisian Cohort study

IntroductionThe low prevalence of some genetic neuro-developmental syndromes associated to psychiatric disorders requests to be integrated in human genome-phenome databases from which pleiotropy can be compiled from by systematic integration of phenotypes associated with genetic loci using phenomic inference tools. Williams-Beuren syndrome (WBS) is a neurodevelopmental disorder related to elastin gene at 7q11.23. Anxiety, depression and attention problems are the main behavioral problems found in WBS with no gender differences. Significant differences between cohorts are reported in particular regarding somatic complaints and aggressive behavior.ObjectivesHere, we report a Tunisian cohort of WBS patients for whom clinical behavioral phenotypes as well as genetic features are detailed.MethodsSixteen patients from Sfax, Tunisia were referred for genetic assessment due to a suspected WBS syndrome.ResultsGenetic evaluation using fluorescent in situ hybridization confirmed 7q11.23 microdeletion in only eight patients. Comparison of detailed behavioral phenotypes revealed differences between age groups, gender groups and genetic groups. Anxiety and depression were recorded in the two older male patients and aggressive behavior was recorded in only two boys. The severity of behavioral features were dependent to familial environment and to parental socio-economic and educational levels.ConclusionsA more complete understanding of phenomic space is critical for elucidating genome-phenome relationships mediating neurodevelopmental disorder associated to psychiatric diseases for assessing and managing psychiatric and behavioral risks in young syndromic children.DisclosureNo significant relationships.

Too cool to fight: Is ambient temperature associated with male aggressive behavior in the mesquite lizard?

AbstractAggressive behavior is performed in the context of intraspecific competition for gaining access to mates, food, or suitable territories. However, aggressive confrontations may divert time and energy from other important activities and increase the likelihood of suffering physical injury or predation. Aggressive behavior is particularly costly for ectotherms because it may reduce the time available for thermoregulation, which is a time‐consuming activity but indispensable for adequate maintenance of metabolic processes. In this study, we analyzed the long‐term effect of the thermal quality (i.e. the degree of discrepancy between the temperatures available in a given environment and temperatures that animals prefer) on the aggressive behavior of the mesquite lizard Sceloporus grammicus. Our hypothesis was that time allocated to aggressive behavior in low thermal quality environments is diverted from time spent on the acquisition and maintenance of an adequate body temperature. Accordingly, we found that lizards from the low thermal quality location (i.e. low environmental temperature) exhibited less aggressive behavior than those captured in middle and high thermal quality locations. Our results show that in the low thermal quality location aggressive behavior was almost absent, suggesting that this behavior may interfere with the acquisition and maintenance of an adequate body temperature. Therefore, it is likely that the benefits of thermoregulation outweigh those of aggressive behavior at low thermal quality locations.

Strain differences in post-castration sexual and aggressive behavior in male mice

The degree to which male sexual behavior and territorial aggression are regulated by gonadal steroid hormones depends strongly on species and experience. While castration abolishes male sexual behavior in most laboratory rodents, approximately one third of B6D2F1 mice retain the full repertoire of male sexual behaviors long term (“maters”). It is not yet known whether maters retain other behaviors that typically rely on gonadal steroids to a greater extent than non-maters. In this study, we tested aggressive behavior in B6D2F1 males and males of each parental strain (C57BL/6J and DBA/2J) in the resident intruder paradigm before and after castration, as well as male sexual behavior after castration. Before castration, B6D2F1 residents displayed more attacks compared to DBA/2J males (p < 0.05). There was no difference in attack frequency between B6D2F1 and C57BL/6J males nor between DBA/2J and C57BL/6J males (p > 0.2). A greater proportion of hybrid males demonstrated intromissions and the ejaculatory reflex compared to males of either parental strain (p < 0.01). After castration, B6D2F1 residents attacked more than C57BL/6J males, but not DBA/2 J males (p < 0.05; p > 0.2). There was no difference in post-castration attack frequency between maters and non-maters (p > 0.7). Finally, residents that attacked during all 3 pre-castration resident intruder tests displayed more attacks post-castration than animals that attacked during 1 pre-castration test (p < 0.05). These data suggest that strain and experience influence the expression of aggressive behavior after castration and warrant future study in experience-induced transient increases in extragonadal testosterone.

A Combined Administration of Testosterone and Arginine Vasopressin Affects Aggressive Behavior in Males.

Aggressive behavior is modulated by many factors, including personality and cognition, as well as endocrine and neural changes. To study the potential effects on the reaction to provocation, which was realized by an ostensible opponent subtracting money from the participant, we administered testosterone (T) and arginine vasopressin (AVP) or a respective placebo (PL). Forty males underwent a functional magnetic resonance imaging session while performing a provocation paradigm. We investigated differential hormone effects and the potential influence of Machiavellian traits on punishment choices (monetary subtractions by the participant) in the paradigm. Participants in the T/AVP group subtracted more money when they were not provoked but showed increased activation in the inferior frontal gyrus and inferior parietal lobule during feedback compared to PL. Higher Machiavellian traits significantly increased punishing behavior independent of provocation only in this group. The pilot study shows that T/AVP affects neural and behavioral responses during a provocation paradigm while personality characteristics, such as Machiavellian trait patterns, specifically interact with hormonal influences (T/AVP) and their effects on behavior.

A resource-poor developmental diet reduces adult aggression in male Drosophila melanogaster

Aggressive behaviours occur throughout the animal kingdom and agonistic contests often govern access to resources. Nutrition experienced during development has the potential to influence aggressive behaviours in adults through effects on growth, energy budgets and an individual’s internal state. In particular, resource-poor developmental nutrition might decrease adult aggression by limiting growth and energy budgets, or alternatively might increase adult aggression by enhancing motivation to compete for resources. However, the direction of this relationship—and effects of developmental nutrition experienced by rivals—remains unknown in most species, limiting understanding of how early-life environments contribute to variation in aggression. We investigated these alternative hypotheses by assessing male-male aggression in adult fruit flies, Drosophila melanogaster, that developed on a low-, medium- or high-resource diet, manipulated via yeast content. We found that a low-resource developmental diet reduced the probability of aggressive lunges in adults, as well as threat displays against rivals that developed on a low-resource diet. These effects appeared to be independent of diet-related differences in body mass. Males performed relatively more aggression on a central food patch when facing rivals of a low-resource diet, suggesting that developmental diet affects aggressive interactions through social effects in addition to individual effects. Our finding that resource-poor developmental diets reduce male-male aggression in D. melanogaster is consistent with the idea that resource budgets mediate aggression and in a mass-independent manner. Our study improves understanding of the links between nutrition and aggression.Significance statementEarly-life nutrition can influence social behaviours in adults. Aggression is a widespread social behaviour with important consequences for fitness. Using the fruit fly, Drosophila melanogaster, we show that a poor developmental diet reduces aspects of adult aggressive behaviour in males. Furthermore, males perform more aggression near food patches when facing rivals of poor nutrition. This suggests that early-life nutrition affects aggressive interactions through social effects in addition to individual effects.

Psychological stressor caused alpha-male non-human-primate Macaca fascicularis to become agonistic when struggling over food

Primates are the object of increased research recently. Experiments on non-human-primates (NHP) can determine their psychological level. NHP Macaca fascicularis is a primate that lives socially with a social hierarchy. Alpha-male becomes the leader of the group. Beneficial access is higher in alpha-male, against the conflicts to be initiated for certain interests. This study provides an overview of alpha-male aggressiveness in groups based on psychological stressors obtained during field observations. The research was conducted at Mbah Agung Karangbanar Religious Tourism Park, Central Java, Indonesia, group-size of 12 adult male, 14 adult female, 8 sub-adult male, 9 sub-adult female, 10 juvenile male, 14 juvenile female, and 6 infants. Aggressive observation (sampling-rules) is behavioral-animal sampling on alpha-male individuals and one individual for each age group as the subject of observation. Observations were carried out for 8 days with one-zero sampling. Adult male and alpha-male aggressive behavior ranked the highest during observation, that psychological stressors obtained.

A circuit logic for sexually shared and dimorphic aggressive behaviors in Drosophila

Aggression involves both sexually monomorphic and dimorphic actions. How the brain implements these two types of actions is poorly understood. We have identified three cell types that regulate aggression in Drosophila: one type is sexually shared, and the other two are sex specific. Shared common aggression-promoting (CAP) neurons mediate aggressive approach in both sexes, whereas functionally downstream dimorphic but homologous cell types, called male-specific aggression-promoting (MAP) neurons in males and fpC1 in females, control dimorphic attack. These symmetric circuits underlie the divergence of male and female aggressive behaviors, from their monomorphic appetitive/motivational to their dimorphic consummatory phases. The strength of the monomorphic → dimorphic functional connection is increased by social isolation in both sexes, suggesting that it may be a locus for isolation-dependent enhancement of aggression. Together, these findings reveal a circuit logic for the neural control of behaviors that include both sexually monomorphic and dimorphic actions, which may generalize to other organisms.

Chronic social defeat stress in female mice leads to sex-specific behavioral and neuroendocrine effects

Over the years, it has become increasingly clear that males and females respond differently towards environmental stressors, highlighting the importance of including both sexes when studying the effects of stress. This study aims to provide further insight into the detailed consequences of exposing female mice to 21 days of chronic social defeat stress (CSDS). We used a protocol that relies on the ability of odorants and pheromones in male urine to trigger male mouse aggressive behavior. Collected male C57Bl/6n urine was applied to female C57Bl/6n mice who were then attacked by a novel male CD1 mouse each day according to the CDSD protocol. Control females were pair-housed and handled daily. Physiological, neuroendocrine and behavioral changes were evaluated during the experiment. CSDS exposure resulted in number of physiological changes, such as body weight gain, enlarged adrenals and reduced thymus weight, exaggerated HPA-axis negative feedback and increased anxiety-like behavior. However, no generalized social avoidance behavior was observed. This study provides important insights in the physiological, neuroendocrine and behavioral responses of female mice to CSDS, which are partially dependent on estrous cycle stage. This protocol will allow direct comparison of male and female responses to CSDS and enable sex-specific study of mechanisms underlying individual stress resilience. Lay summary In this study we found that there are differences in the way that female and male mice respond towards chronic social stress conditions when it comes to behavior and hormonal changes.

Male-specific features are reduced in Mecp2-null mice: analyses of vasopressinergic innervation, pheromone production and social behaviour.

Deficits in arginine vasopressin (AVP) and oxytocin (OT), two neuropeptides closely implicated in the modulation of social behaviours, have been reported in some early developmental disorders and autism spectrum disorders. Mutations in the X-linked methyl-CpG-binding protein 2 (MECP2) gene are associated to Rett syndrome and other neuropsychiatric conditions. Thus, we first analysed AVP and OT expression in the brain of Mecp2-mutant mice by immunohistochemistry. Our results revealed no significant differences in these systems in young adult Mecp2-heterozygous females, as compared to WT littermates. By contrast, we found a significant reduction in the sexually dimorphic, testosterone-dependent, vasopressinergic innervation in several nuclei of the social brain network and oxytocinergic innervation in the lateral habenula of Mecp2-null males, as compared to WT littermates. Analysis of urinary production of pheromones shows that Mecp2-null males lack the testosterone-dependent pheromone darcin, strongly suggesting low levels of androgens in these males. In addition, resident-intruder tests revealed lack of aggressive behaviour in Mecp2-null males and decreased chemoinvestigation of the intruder. By contrast, Mecp2-null males exhibited enhanced social approach, as compared to WT animals, in a 3-chamber social interaction test. In summary, Mecp2-null males, which display internal testicles, display a significant reduction of some male-specific features, such as vasopressinergic innervation within the social brain network, male pheromone production and aggressive behaviour. Thus, atypical social behaviours in Mecp2-null males may be caused, at least in part, by the effect of lack of MeCP2 over sexual differentiation.

Posterior amygdala regulates sexual and aggressive behaviors in male mice.

Sexual and aggressive behaviors are fundamental to animals’ survival and reproduction. The medial preoptic nucleus (MPN) and ventrolateral part of ventromedial hypothalamus (VMHvl) are essential regions for male sexual and aggressive behaviors, respectively. While key inhibitory inputs to VMHvl and MPN are identified, the extra-hypothalamic excitatory inputs essential for the social behaviors remain elusive. Here we identify estrogen receptor alpha (Esr1) expressing cells in posterior amygdala (PA) as a main source of excitatory inputs to hypothalamus and key mediators for mating and fighting in male mice. We find two largely distinct PA subpopulations that differ in connectivity, gene expression, in vivo responses and social behavior relevance. MPN projecting PAEsr1+ cells are activated during mating and necessary and sufficient for male sexual behaviors, while VMHvl projecting PAEsr1+ are excited during inter-male aggression and promote attacks. These findings place PA as a key node in both male aggression and reproduction circuits.