Dominant-subordinate Relationships Research Articles

대중음악 가창연주론 연구 - 스타일 반영주의를 넘어서

This study theoretically examines singing in popular music. This study defines “style reflectionism” as the view of singing style dominated by structure, system, and norm. Along with criticizing reflectionist view, this study constructs a preliminary theory of popular music singing performance. Singing and vocal style in popular music is more diverse than western classical music, but there is an obvious tendency of convention in each genre’s context. Existing studies on singing focus on interpretation of techniques and music analysis. Hence, it is necessary to reconsider the theoretical approach of popular music singing itself beyond convention as normatizing and representing. Although music studies considering performance and performativity have recently emerged, there remains a gap in the literature. John Potter, a tenor and a scholar, not only theorized singing style but also made a valid approach. Potter’s theory, which covers both traditions of western classical and popular music, explains how specific singing style exercises hegemonic power contemplating sociocultural conditions and structure. However, he schematizes the historical development of style centered on ideology, and does not overstep the limits of style reflectionism. This study reconsider Louis Althusser’s ideas of ideology, subject, and interpellation as constructing the timbral subject (subject of timbre). Furthermore, Roland Barthes’s concept of “the grain of the voice” is also reconsidered. These are useful for building and considering an anti-reflectionist view. Finally, this study argues that the theory of popular music singing performance beyond style reflectionism can be imagined by emphasizing singularity, not in a dominant-subordinate relationship between universality and specificity, which is continuous differentiation of meaning and subjectivity.

Dopamine D2 receptor within the intermediate region of the lateral septum modulate social hierarchy in male mice

The dopamine (DA) system has long been involved in social hierarchies; however, the specific mechanisms have not been elucidated. The lateral septum (LS) is a limbic brain structure that regulates various emotional, motivational, and social behaviors. DA receptors are abundantly expressed in the LS, modulating its functions. In this study, we evaluated the functions of DA receptors within different subregions of the LS in social dominance using a confrontation tube test in male mice. The results showed that mice living in social groups formed linear dominance hierarchies after a few days of cohousing, and the subordinates showed increased anxiety. Fos expressions was elevated in the entire LS after a confrontation tube test in the subordinates. However, DA neurons were more activated in the dominates within the ventral tegmental area and the dorsal raphe nucleus. Quantitative real-time polymerase chain reaction results showed that D2 receptor (D2R) within the intermediate region of the LS (LSi) were elevated in the subordinate. In the following pharmacological studies, we found simultaneous D2R activation in the dominants and D2R inhibition in the subordinates switched the original dominant–subordinate relationship. The aforementioned results suggested that D2R within the LSi plays an important role in social dominance in male mice. These findings improve our understanding of the neural mechanisms underlying the social hierarchy, which is closely related to our social life and happiness.

5-HT1A receptor in the central amygdala and 5-HT2A receptor in the basolateral amygdala are involved in social hierarchy in male mice

Most social animals self-organize into dominance hierarchies that strongly influence their behavior and health. The serotonin (5-HT) system is believed to play an important role in the formation of social hierarchy. 5-HT receptors are abundantly expressed in the amygdala, which is considered as the central node for the perception and learning of social hierarchy. In this study, we assessed the functions of various 5-HT receptor subtypes related to social rank determination in different subregions of the amygdala using the confrontation tube test in mice. We revealed that most adult C57BL/6 J male mice exhibited a linear social rank after a few days of cohousing. The tube test ranks were slightly related to anxiety-like behavioral performance. After the tube test, the amygdala and 5-HT neurons in the dorsal raphe nucleus were activated in lower-rank individuals. Quantitative real-time polymerase chain reaction analysis revealed that despite the high expression of 5-HT1A receptor mRNA in the central amygdala (CeA), 5-HT2A receptor mRNA expression was downregulated in the basolateral amygdala (BLA) in higher-rank individuals. The dominant–subordinate relationship between mouse pairs could be switched via pharmacological modulation of these receptors in CeA and BLA, suggesting that these expression changes are essential for establishing social ranks. Our findings provide novel insights into the divergent functions of 5-HT receptors in the amygdala related to social hierarchy, which is closely related to our health and welfare.

Dopamine D2 receptors in the dorsomedial prefrontal cortex modulate social hierarchy in male mice.

Social hierarchy greatly influences behavior and health. Both human and animal studies have signaled the medial prefrontal cortex (mPFC) as specifically related to social hierarchy. Dopamine D1 receptors (D1Rs) and D2 receptors (D2Rs) are abundantly expressed in the mPFC, modulating its functions. However, it is unclear how DR-expressing neurons in the mPFC regulate social hierarchy. Here, using a confrontation tube test, we found that most adult C57BL/6J male mice could establish a linear social rank after 1 week of cohabitation. Lower rank individuals showed social anxiety together with decreased serum testosterone levels. D2R expression was significantly downregulated in the dorsal part of mPFC (dmPFC) in lower rank individuals, whereas D1R expression showed no significant difference among the rank groups in the whole mPFC. Virus knockdown of D2Rs in the dmPFC led to mice being particularly prone to lose the contests in the confrontation tube test. Finally, simultaneous D2R activation in the subordinates and D2R inhibition in the dominants in a pair switched their dominant-subordinate relationship. The above results indicate that D2Rs in the dmPFC play an important role in social dominance. Our findings provide novel insights into the divergent functions of prefrontal D1Rs and D2Rs in social dominance, which may contribute to ameliorating social dysfunctions along with abnormal social hierarchy.

“What a nasty girl!” incivility and gendered symbolic violence in news discussions

ABSTRACT This study examines conversations developed in the virtual public sphere to identify if a user’s gender affects the presence of incivility in news comment sections. By relying on a mixed-method analysis of 1,961 news comments published on a Chilean news website, we observed the extent to which uncivil speech and gendered symbolic violence traits are used to reinforce stereotypes against women. Our results show men are more likely to post uncivil comments, while women use fewer profanities, insulting language, and stereotypes. One of our most intriguing findings is that men tend to receive more uncivil replies that women, mostly because they are more likely to initiate uncivil conversations, which in turn triggers uncivil replies and increases the odds of uncivil comment threads. As such, news outlets looking for enhancing healthy discussions should encourage greater participation of female users in their comment sections. We also identified the presence of hegemonic masculinity discourses referring to women and their gender roles in society. These findings reveal that comment sections mirror a social hierarchy in which men have a position of power that allows them to be more uncivil. Consequently, the virtual public sphere replicates the dominant-subordinate relationships described by previous research.

Bargain to Be Dominant.

AbstractThis article proposes an evolutionary game theoretical model in which individuals negotiate to reach a compromise settlement on who takes the dominant role in a dominant-subordinate relationship. The negotiation process is formalized by bargaining theory in economics, which makes our model different from alternative models on the formation of dominant-subordinate relationships based on detailed biological mechanisms. We find that evolution leads to a "cooperative" ("selfish") behavior when an individual takes the dominant (subordinate) role. For example, consider two Polistes wasps in a nest-building pair who try to determine the role assignment of the queen and the subordinate cofoundress. After the roles are assigned, the queen chooses between either sharing or monopolizing reproduction, and the subordinate chooses between exerting either a high or a low effort in rearing or foraging activities. According to our model's prediction, the queen's behavior (sharing reproduction) increases the collective fitness of the colony but potentially hurts her reproductive interest, while the subordinate's behavior (exerting a low effort) decreases the productivity of the colony but helps her to save energy. Such a behavior pair is evolutionarily stable because it guarantees an individual to have the comparative advantage in taking the dominant role against any other individuals via negotiation. This result may shed new light on understanding the formation of dominant-subordinate relationships. In addition, agnostic of detailed biological mechanisms, our mathematical formulation of dominant-subordinate relationships might also have wide applications in animal behavior and beyond, as its empirical support is found in article wasps and humans.

Intimacy across species boundaries: Interspecific allopreening between Spot-necked (Stachyris strialata) and Nonggang Babblers (S. nonggangensis).

Allopreening occurs in many species of birds and is known for providing hygienic and social benefits. While this behavior has been extensively studied among conspecifics, its occurrence among different species remains little known. Outside of captive environments, only a few records of interspecific allopreening exist. In this study, we describe our observations of the interspecific allopreening behavior between Spot‐necked (Stachyris strialata) and Nonggang Babblers ( S. nonggangensis) in a non‐captive environment in southern China. To our knowledge, these observations represent the first record of interspecific allopreening in the family Timaliidae. We suggest that this understudied behavior is most likely related to the dominant–subordinate relationship between these two species: either the dominant species preening the subordinate species to assert dominance or the subordinate species preening the dominant species to reduce tensions by appeasement. We also suggest interspecific allopreening may not be as rare as we thought if we study this behavior under circumstances where different species are close to each other. This study contributes to our understanding of not only the potential mechanism(s) behind interspecific allopreening but also the behavioral ecology of the vulnerable Nonggang Babbler.

Inheritance of social dominance is associated with global sperm DNA methylation in inbred male mice.

Dominance relationships between males and their associated traits are usually heritable and have implications for sexual selection in animals. In particular, social dominance and its related male pheromones are heritable in inbred mice; thus, we wondered whether epigenetic changes due to altered levels of DNA methylation determine inheritance. Here, we used C57BL/6 male mice to establish a social dominance-subordination relationship through chronic dyadic encounters, and this relationship and pheromone covariation occurred in their offspring, indicative of heritability. Through transcriptome sequencing and whole-genome DNA methylation profiling of the sperm of both generations, we found that differential methylation of many genes was induced by social dominance-subordination in sires and could be passed on to the offspring. These methylated genes were mainly related to growth and development processes, neurodevelopment, and cellular transportation. The expression of the genes with similar functions in whole-genome methylation/bisulfite sequencing was also differentiated by social dominance-subordination, as revealed by RNA-seq. In particular, the gene Dennd1a, which regulates neural signaling, was differentially methylated and expressed in the sperm and medial prefrontal cortex in paired males before and after dominance-subordination establishment, suggesting the potential epigenetic control and inheritance of social dominance-related aggression. We suggest that social dominance might be passed on to male offspring through sperm DNA methylation and that the differences could potentially affect male competition in offspring by affecting the development of the nervous system.

Blues as a Symbolic Resistance and Representation of Countercultural Groups in the United States in the late 19 – early 20 centuries

Introduction. This article examines the blues music tradition from the perspective of the use of symbolic representations by the creators of this form of culture, which formed a unique “hidden transcripts” transmitted by certain socio-cultural groups that lived and worked in a certain historical era. Since the blues tradition in the United States originates in black communities, in terms of the self-representation of representatives of this groups to the dominant culture, we can talk abut the music of this socio-cultural period of American history as an instrument for conveying “hidden transcripts”.Methodology and sources. The author used the comparative-historical methodology in the context of studying the relationship of domination and subordination between groups and individuals. All subordinate groups use resistance strategies that go unnoticed by superior groups. Open public interaction between dominant and oppressed groups is defined by the term “public transcripts” and criticism of power that takes place offstage by the term “hidden transcripts”. Forms of hidden transcripts are coded demonstrations by oppressed groups to resist and oppose themselves, their way of life, and the difficulties of inequality to dominant groups.Results and discussion. In the context of any dominance-subordination relationship, spaces of autonomy for oppressed racial and social groups were formed, in which there was an opportunity for self-expression as acts of resistance to existing inequality, which found its expression in songs, folk tales, clothing, language, and religious expression. The development of hidden transcripts depends not only on the creation of relatively uncontrollable physical places and free time, but also on the active human agents who create and disseminate them. The bearers are likely to be as socially marginalized as the places where they gather.Conclusion. Oppressed or marginalized groups create not just their art and culture as a social group caught up in a certain cultural context, but a culture of integration into society, as well as a culture of interaction with the social hierarchy in which these groups have a rather low position. Groups excluded from the decision-making process or weakly involved in it, develop their own models for demonstrating their presence in society, and also try to convey their content to all other members of society, whether groups and individuals close or distant in status and hierarchy.

First report of male–male combat in free-ranging Amazonian Common Lanceheads (Bothrops atrox)

In many snakes, males engage in agonistic interactions (male–male combat) apparently to establish dominant–subordinate relationships to gain priority access to reproductive females. In the Neotropical genus Bothrops Wagler, 1824 (∼45 species), male–male combat has been recorded only in three species of the monophyletic Bothrops atrox group. However, most male combats recorded in this clade occurred in captivity, an environment that facilitates the emergence of agonistic interactions. Here, we provide the first record of male–male combat in free-ranging Amazonian Common Lanceheads (Bothrops atrox (Linnaeus, 1758)) and discuss the implications of this observation for the species mating system. During fieldwork, we found one immature female and five active adult males, two of them fighting. These observations suggest that reproductive male B. atrox actively search and compete for widely dispersed and scarce receptive females.

Distinct Roles for Prefrontal Dopamine D1 and D2 Neurons in Social Hierarchy.

Neuronal activity in the prefrontal cortex (PFC) controls dominance hierarchies in groups of animals. Dopamine (DA) strongly modulates PFC activity mainly through D1 receptors (D1Rs) and D2 receptors (D2Rs). Still, it is unclear how these two subpopulations of DA receptor-expressing neurons in the PFC regulate social dominance hierarchy. Here, we demonstrate distinct roles for prefrontal D1R- and D2R-expressing neurons in establishing social hierarchy, with D1R+ neurons determining dominance and D2R+ neurons for subordinate. Ex vivo whole-cell recordings revealed that the dominant status of male mice correlates with rectifying AMPAR transmission and stronger excitatory synaptic strength onto D1R+ neurons in PFC pyramidal neurons. In contrast, the submissive status is associated with higher neuronal excitability in D2R+ neurons. Moreover, simultaneous manipulations of synaptic efficacy of D1R+ neurons in dominant male mice and neuronal excitability of D2R+ neurons of their male subordinates switch their dominant-subordinate relationship. These results reveal that prefrontal D1R+ and D2R+ neurons have distinct but synergistic functions in the dominance hierarchy, and DA-mediated regulation of synaptic strengths acts as a powerful behavioral determinant of intermale social rank.SIGNIFICANCE STATEMENT Dominance hierarchy exists widely among animals who confront social conflict. Studies have indicated that social status largely relies on the neuronal activity in the PFC, but how dopamine influences social hierarchy via subpopulation of prefrontal neurons is still elusive. Here, we explore the cell type-specific role of dopamine receptor-expressing prefrontal neurons in the dominance-subordinate relationship. We found that the synaptic strength of D1 receptor-expressing neurons determines the dominant status, whereas hyperactive D2-expressing neurons are associated with the subordinate status. These findings highlight how social conflicts recruit distinct cortical microcircuits to drive different behaviors and reveal how D1- and D2-receptor enriched neurocircuits in the PFC establish a social hierarchy.

Social effects on AVT and CRF systems

Stress and aggression have negative effects on fish welfare and productivity in aquaculture. Thus, research to understand aggression and stress in farmed fish is required. The neuropeptides arginine-vasotocin (AVT) and corticotropin-releasing factor (CRF) are involved in the control of stress and aggression. Therefore, we investigated the effect of agonistic interactions on the gene expression of AVT, CRF and their receptors in juvenile rainbow trout (Oncorhynchus mykiss). The social interactions lead to a clear dominant-subordinate relationship with dominant fish feeding more and being more aggressive. Subordinate fish had an upregulation of the AVT receptor (AVT-R), an upregulation of CRF mRNA levels, and higher plasma cortisol levels. The attenuating effect of AVT on aggression in rainbow trout is proposed to be mediated by AVT-R, and the attenuating effect of the CRF system is proposed to be mediated by CRF.

Resistance and Representation: The Making of Chinese Identity in the Art of The Yiyanhui and the Equator Art Society in 1950s Singapore

This paper examines the social realist paintings of the art groups Yiyanhui and the Equator Art Society which emerged during the 1950s in Malaya and Singapore. Their works centred on the social functions of art and its subject matters featured the working class, the Japanese occupation and anti-British colonial sentiment. Their artworks are viewed here as cultural productions shaped by the negotiation between dominant-subordinate relationships within a postcolonial framework. It is argued that the artistic productions examined here may be viewed not only for its overarching “social realist” endeavours but, also as a struggle to rewrite the narrative of the Chinese in Malaya against of the prevailing static representations forwarded by the colonial campaign. The first part of the paper illustrates how colonial discourse in the local press propagated an image of the Chinese as inherently susceptible to communism, untrustworthy, and opportunistic. The second part of the paper shows how the artists resisted this essentialist image of Chinese identity and offered a more complex picture of a Chinese-Malayan identity. Through a combination of interviews, written artist’s statements, formal and contextual considerations of the artworks, as well as a cultural studies framework, I demonstrate how a different narrative is being offered by these artists through two related processes in identity construction: qualifications for authenticity and belonging, the articulation of ambivalence. Resistance thus, is explored as encompassing a network of strategies employed by these artists as a way to reject colonialist representations of otherness and gain authorial agency against the intellectual and ideological dominance of colonial discourse.

Social Transmission and Buffering of Hippocampal Metaplasticity after Stress in Mice

In social animals, the behavioral and hormonal responses to stress can be transmitted from one individual to another through a social transmission process, and, conversely, social support ameliorates stress responses, a phenomenon referred to as social buffering. Metaplasticity represents activity-dependent synaptic changes that modulate the ability to elicit subsequent synaptic plasticity. Authentic stress can induce hippocampal metaplasticity, but whether transmitted stress has the same ability remains unknown. Here, using an acute restraint-tailshock stress paradigm, we report that both authentic and transmitted stress in adult male mice trigger metaplastic facilitation of long-term depression (LTD) induction at hippocampal CA1 synapses. Using LTD as a readout of persistent synaptic consequences of stress, our findings demonstrate that, in a male-male dyad, stress transmission happens in nearly half of naive partners and stress buffering occurs in approximately half of male stressed mice that closely interact with naive partners. By using a social-confrontation tube test to assess the dominant-subordinate relationship in a male-male dyad, we found that stressed subordinate mice are not buffered by naive dominant partners and that stress transmission is exhibited in ∼60% of dominant naive partners. Furthermore, the appearance of stress transmission correlates with more time spent in sniffing the anogenital area of stressed mice, and the appearance of stress buffering correlates with more time engaged in allogrooming from naive partners. Chemical ablation of the olfactory epithelium with dichlobenil or physical separation between social contacts diminishes stress transmission. Together, our data demonstrate that transmitted stress can elicit metaplastic facilitation of LTD induction as authentic stress.SIGNIFICANCE STATEMENT Social animals can acquire information about their environment through interactions with conspecifics. Stress can induce enduring changes in neural activity and synaptic function. Current studies are already unraveling the transmission and buffering of stress responses between individuals, but little is known about the relevant synaptic changes associated with social transmission and buffering of stress. Here, we show that authentic and transmitted stress can prime glutamatergic synapses onto hippocampal CA1 neurons to undergo long-term depression. This hippocampal metaplasticity is bufferable following social interactions with naive partners. Hierarchical status of naive partners strongly affects the social buffering effect on synaptic consequences of stress. This work provides novel insights into the conceptual framework for synaptic changes with social transmission and buffering of stress.

EVIDENCE OF SOCIAL STRUCTURE INFLUENCING FEEDING BEHAVIOUR IN CAPTIVE LITTLE BROWN BATS (MYOTIS LUCIFUGUS)

Social rank and personality (consistent behavioural traits) can influence access to resources that could be critical for fat accumulation and survival from disease. For Little Brown Bats (Myotis lucifugus) recovering from the fungal disease white-nose syndrome, understanding behavioural dynamics may also be important for maintaining animals in captivity for conservation research. We hypothesized that Little Brown Bats will exhibit social structure in captivity, and that social rank and personality affect feeding behaviour. We predicted that bats would arrive at the feeding dish in a similar order each night and that higher ranked and more active individuals would spend more time and feed more frequently at the food dish. Bats arrived at the feeding dish in a similar order each night, suggesting that social rank may affect feeding in captive bat colonies. However, neither the order of arrival or personality correlated with feeding behaviour. We recommend that future studies test for the influence of dominant-subordinate relationships on social structure in captive and free-ranging insectivorous bats.

Social network analysis in pigs: impacts of significant dyads on general network and centrality parameters

In general, one animal is considered dominant over another animal if it has won more fights than its opponent. Whether this difference in won and lost fights is significant is neglected in most studies. Thus, the present study evaluates the impact of two different calculation methods for dyadic interactions with a significant asymmetric outcome on the results of social network analysis regarding agonistic interactions of pigs in three different mixing events (weaned piglets, fattening pigs and gilts). Directly after mixing, all animals were video recorded for 17 (fattening pigs, gilts) and 28 h (weaned piglets), documenting agonistic interactions. Two calculation methods for significant dyads, that is, dyadic interactions with a clear dominant subordinate relationship in which one animal has won significantly more fights than its encounter, were proposed: pen individual limits were calculated by a sign test considering the differences of won and lost fights of all dyadic interactions in each pen; dyad individual limits were determined by a one-sided sign test for each individual dyad. For all data sets (ALL, including all dyadic interactions; PEN or DYAD, including only significant dyads according to pen or dyad individual limits), networks were built based on the information of initiator and receiver with the pigs as nodes and the edges between them illustrating attacks. General network parameters describing the whole network structure and centrality parameters describing the position of each animal in the network were calculated. Both pen and dyad individual limits revealed only a small percentage of significant dyads for weaned piglets (12.4% or 8.8%), fattening pigs (4.2% or 0.6%) and gilts (3.6% or 0.4%). The comparison between the data sets revealed only high Spearman’s rank correlation coefficients (rS) for the density, that is, percentage of possible edges that were actually present in the network, whereas the centrality parameters showed only moderate rS values (0.37 to 0.75). Thus, the rank order of the animals changed due to the exclusion of insignificant dyads, which shows that the results obtained from social network analysis are clearly influenced if insignificant dyads are excluded from the analyses. Due to the fact that the pen individual limits consider the overall level of agonistic interactions within each pen, this calculation method should be preferred over the dyad individual limits. Otherwise, too many animals in the group became isolated nodes with zero centrality for which no statement about their position within the network can be made.

Temporal microstructure of dyadic social behavior during relationship formation in mice.

Socially competent animals must learn to modify their behavior in response to their social partner in a contextually appropriate manner. Dominant-subordinate relationships are a particularly salient social context for mice. Here we observe and analyze the microstructure of social and non-social behaviors as 21 pairs of outbred CD-1 male mice (Mus Musculus) establish dominant-subordinate relationships during daily 20-minute interactions for five consecutive days in a neutral environment. Firstly, using a Kleinberg burst detection algorithm, we demonstrate aggressive and subordinate interactions occur in bursting patterns followed by quiescent periods rather than being uniformly distributed across social interactions. Secondly, we identify three phases of dominant-subordinate relationship development (pre-, middle-, and post-resolution) by utilizing two statistical methods to identify stability in aggressive and subordinate behavior across these bursts. Thirdly, using First Order Markov Chains we find that dominant and subordinate mice show distinct behavioral transitions, especially between tail rattling and other aggressive/subordinate behaviors. Further, dominant animals engaged in more digging and allogrooming behavior and were more likely to transition from sniffing their partner’s body to head, whereas subordinates were more likely to transition from head sniffing to side-by-side contact. Lastly, we utilized a novel method (Forward Spike Time Tiling Coefficient) to assess how individuals respond to the behaviors of their partner. We found that subordinates decrease their tail rattling and aggressive behavior in response to aggressive but not subordinate behavior exhibited by dominants and that tail rattling in particular may function to deescalate aggressive behavior in pairs. Our findings demonstrate that CD-1 male mice rapidly establish dominance relationships and modify their social and non-social behaviors according to their current social status. The methods that we detail also provide useful tools for other researchers wishing to evaluate the temporal dynamics of rodent social behavior.

Libraries as Contestation Arena of the Stakeholders to Achieve Their Goals

The management of university libraries in Indonesia has been intervened from foreign institutions through a donation of library materials which seem for the benefit of the academic community, but it is for the benefit of the donors. Academicians, especially the young generation, are a target of donation whether as the readers of books donated to the University or as the audience of programs or activities funded by donor agencies. Based on the background, it is found how the library becomes an arena for the contestation of various interests through some “corners” build inside the University Libraries. Using the concepts introduced by Pierre Bourdieu such as arena and capitals. Supported by Vincent Mosco’s theory of political economy of communication as the tools of analysis, this research reveals how the agents involved in the management of the “Corner” use the library as an "arena" to achieve their benefits. The data obtained were grouped based on the sub-theme of types capital, commodification, specialization and structuration Using phenomenological approach, it is found that Corners in the university Libraries are used as an arena of contestation of agents involved in governance to foster capital. Contestation in this study illustrates the phenomenon of actors involved in the management of Corner into the dominant-subordinate relationship.

Fecal Glucocorticoid Response to Periodic Social Stress in Male Green Anoles, Anolis carolinensis

Agonistic encounters necessary for territory establishment and maintenance can be stressful for those involved. Stress responsiveness associated with territorial behavior can occur on both acute and chronic temporal scales contingent upon social status. Social interactions that recur for territory maintenance pose periodic stressors that incur variable physiological costs across social ranks. Adult males of the Green Anole, Anolis carolinensis, experience stressful social encounters during territorial disputes as individuals contest status within a dominance hierarchy. Dominant males in stable territories are known to exhibit greener body coloration and lower levels of stress hormone, corticosterone, relative to their subordinate counterparts. Periodic interactions with novel competitors, however, may induce comparable levels of cumulative glucocorticoid secretion regardless of social status. Glucocorticoid metabolites excreted in feces can be quantified to assess the chronic hypothalamic–pituitary–adrenal (HPA) axis response to periodic social stressors. Fecal glucocorticoid metabolite (FGM) levels in male A. carolinensis were hypothesized to increase in response to novel social encounters that simulated territory establishment and maintenance. Adrenocortical response to recurring episodes of territoriality was predicted to generate similar longitudinal FGM levels across social ranks. FGM analysis was combined with behavioral assessment of body coloration to further contextualize measured stress levels of dominant and subordinate anoles. Prolonged social interaction led to similarly increased levels of fecal glucocorticoid metabolites in both dominant and subordinate anoles relative to those that were solitary. This study provides an alternative perspective on the activity of the HPA axis in dominant–subordinate relationships of A. carolinensis over prolonged periods of territoriality.

The Role of Estrogen Receptor β (ERβ) in the Establishment of Hierarchical Social Relationships in Male Mice.

Acquisition of social dominance is important for social species including mice, for preferential access to foods and mates. Male mice establish social rank through agonistic behaviors, which are regulated by gonadal steroid hormone, testosterone, as its original form and aromatized form. It is well known that estrogen receptors (ERs), particularly ER α (ERα), mediate effects of aromatized testosterone, i.e., 17β-estradiol, but precise role played by ER β (ERβ) is still unclear. In the present study, we investigated effects of ERβ gene disruption on social rank establishment in male mice. Adult male ERβ knockout (βERKO) mice and their wild type (WT) littermates were paired based on genotype- and weight-matched manner and tested against each other repeatedly during 7 days experimental period. They underwent 4 trials of social interaction test in neutral cage (homogeneous set test) every other day. Along repeated trials, WT but not βERKO pairs showed a gradual increase of agonistic behaviors including aggression and tail rattling, and a gradual decrease of latency to social rank determination in tube test conducted after each trial of the social interaction test. Analysis of behavioral transition further suggested that WT winners in the tube test showed one-sided aggression during social interaction test suggesting WT pairs went through a process of social rank establishment. On the other hand, a dominant-subordinate relationship in βERKO pairs was not as apparent as that in WT pairs. Moreover, βERKO mice showed lower levels of aggressive behavior than WT mice in social interaction tests. These findings collectively suggest that ERβ may play a significant role in the establishment and maintenance of hierarchical social relationships among male mice.