Stable Hierarchy Research Articles

Allocation of Limited Resources in a System with a Stable Hierarchy (on the Example of the Prospective Military Communications System)

The article is devoted to the formalization of the resource allocation problem in the hierarchical social system, where resources are distributed according to the agent's role in the system. We study the application of a proposed mathematical model to the organization of the special purpose communication network. Also, we propose an algorithm of the automatic partitioning of the radio communication system according to the role of nodes. None of the nodes has complete knowledge about the entire communication system, and the initially unknown information about the purpose of nodes is established in the process of the beacons exchange.

Weighted Spacer Design for Elevated Temperature Conditions to Mitigate Barite Settling by Identifying Suitable Viscosifier

Any successful primary cementing operation at elevated temperature condition requires an efficient displacement of fluid surrounding the casing by cement slurry. In such conditions the cement slurry should be designed in such a way that it should be compatible with both cement and drilling mud. To achieve these requirements we designed the cement slurry with weighted spacer. Spacer is a barrier between cement & mud so that they should not mix with each other, also all these fluids should be incompatible inorder to avoid cement aggregation. The displacement efficiency during cementation is directly dependent on discharge rate, but however due to formation fracture pressure constraints, the discharge rate is limited, hence designing spacer becomes very crucial. This phenomenon becomes more pronounced at higher temperature as turbulent flow efficiency reduces due to the presence of weighting agent. The drive of the present work is to identify a suitable viscosifier to avoid settling of weighing agents in spacer and to maintain the stability of rheology admixture at elevated temperature condition. Laboratory tests were performed for compatible deformation and flow of matter with cement slurry-spacer-mud at temperature range (80-140°C) on a rotational viscometer as per the procedure of API RP 10B-2. The volumetric proportions of the cement slurry/spacer and spacer/mud admixtures were prepared with various ratios: 95/5, 75/25, 50/50, 25/75, and 5/95. Rheological compatibility of fluids (cement & spacer and mud & spacer) is evaluated by computing the R-Index Value (R) which is calculated by subtracting highest 100 rpm reading of admixture from highest rpm reading for an individual fluid for the given range of elevated temperature condition. The calculated R-Index Value can then be utilized to comment on fluid compatibility. After finalization of chemical compatibility, rheological hierarchy was achieved by incorporating the friction pressure loss with respect to discharge rate of an individual fluid for the given range of elevated temperature condition. The spacer system used achieved stable compatibility and efficient rheological hierarchy at elevated temperature cementing conditions. In addition, by comparing the results between the two different spacer systems, the role of hydration in attaining rheological compatibility is computed. This study will in turn prove helpful in figuring out the better spacer system which will play a vital role for better displacement and cementation quality.

The Outcomes of Introducing the Effective Contract with Medical Staff

The paper presents the results of a study of changes in the salary schemes and working conditions of medical staff, their labor motivation and the compliance of these changes with the objectives of the so-called “effective”, performance-based, contract being introduced. The data from a set of surveys of employees at public medical facilities in 2009–2018 served as the empirical base of the study. It is shown that the introduction of the effective contract had changed the role of factors determining the salary of medical workers. Whereas earlier qualification had been the leading factor, afterwards it was the volume and quality of the work performed as well as the outcomes of a given medical institution or unit. Most doctors had increased the amount of work they do, and the secondary employment of medical staff had slightly been reduced. Survey data indicate quite a stable hierarchy of labor motives among medical workers, the leading ones being earning money, professional interest in work, and altruism. In 2018, the role of the guaranteed employment motive was elevated. Among the positive changes are an increase in the satisfaction of medical workers with the salary, conditions for advanced training, and rules of remuneration. The identified outcomes are generally consistent with the objectives of introducing the effective contract, and they allow one to argue that the new salary scheme has had a positive impact on the labor motivation of medical staff. However, the conclusion of an effective contract was noted by only half of respondents. For the rest, it all boiled down to an increase in salary. These results indicate serious failures in the administration of this reform.

Exogenous testosterone increases status-seeking motivation in men with unstable low social status

Testosterone is associated with status-seeking behaviors such as competition, which may depend on whether one wins or loses status, but also on the stability of one’s status. We examined (1) to what extent testosterone administration affects competition behavior in repeated social contests in men with high or low rank, and (2), whether this relationship is moderated by hierarchy stability, as predicted by the status instability hypothesis. Using a real effort-based design in healthy male participants (N = 173 males), we first found that testosterone (vs. placebo) increased motivation to compete for status, but only in individuals with an unstable low status. A second part of the experiment, tailored to directly compare stable with unstable hierarchies, indicated that exogenous testosterone again increased competitive motivation in individuals with a low unstable status, but decreased competition behavior in men with low stable status. Additionally, exogenous testosterone increased motivation in those with a stable high status. Further analysis suggested that these effects were moderated by individuals’ trait dominance, and genetic differences assessed by the androgen receptor (CAG-repeat) and dopamine transporter (DAT1) polymorphisms. Our study provides evidence that testosterone specifically boosts status-related motivation when there is an opportunity to improve one’s social status. The findings contribute to our understanding of testosterone’s causal role in status-seeking motivation in competition behavior, and indicate that testosterone adaptively increases our drive for high status in a context-dependent manner. We discuss potential neurobiological pathways through which testosterone may attain these effects on behavior.

Donor-to-Donor Heterogeneity in the Clonal Dynamics of Transplanted Human Cord Blood Stem Cells in Murine Xenografts.

Umbilical cord blood (UCB) provides an alternative source of hematopoietic stem cells (HSCs) for allogeneic transplantation. Administration of sufficient donor HSCs is critical to restore recipient hematopoiesis and to maintain long-term polyclonal blood formation. However, due to lack of unique markers, the frequency of HSCs among UCB CD34+ cells is the subject of ongoing debate, urging for reproducible strategies for their counting. Here, we used cellular barcoding to determine the frequency and clonal dynamics of human UCB HSCs and to determine how data analysis methods affect these parameters. We transplanted lentivirally barcoded CD34+ cells from 20 UCB donors into Nod/Scid/IL2Ry-/- (NSG) mice (n = 30). Twelve recipients (of 8 UCB donors) engrafted with >1% GFP+ cells, allowing for clonal analysis by multiplexed barcode deep sequencing. Using multiple definitions of clonal diversity and strategies for data filtering, we demonstrate that differences in data analysis can change clonal counts by several orders of magnitude and propose methods to improve their consistency. Using these methods, we show that the frequency of NSG-repopulating cells was low (median ∼1 HSC/104 CD34+ UCB cells) and could vary up to 10-fold between donors. Clonal patterns in blood became increasingly consistent over time, likely reflecting initial output of transient progenitors, followed by long-term HSCs with stable hierarchies. The majority of long-term clones displayed multilineage output, yet clones with lymphoid- or myeloid-biased output were also observed. Altogether, this study uncovers substantial interdonor and analysis-induced variability in the frequency of UCB CD34+ clones that contribute to post-transplant hematopoiesis. As clone tracing is increasingly relevant, we urge for universal and transparent methods to count HSC clones during normal aging and upon transplantation.

Latency to Reward Predicts Social Dominance in Rats: A Causal Role for the Dopaminergic Mesolimbic System.

Reward signals encoded in the mesolimbic dopaminergic system guide approach/seeking behaviors to all varieties of life-supporting stimuli (rewards). Differences in dopamine (DA) levels have been found between dominant and submissive animals. However, it is still unclear whether these differences arise as a consequence of the rewarding nature of the acquisition of a dominant rank, or whether they preexist and favor dominance by promoting reward-seeking behavior. Given that acquisition of a social rank determines animals’ priority access to resources, we hypothesized that differences in reward-seeking behavior might affect hierarchy establishment and that modulation of the dopaminergic system could affect the outcome of a social competition. We characterized reward-seeking behaviors based on rats’ latency to get a palatable-reward when given temporary access to it. Subsequently, rats exhibiting short (SL) and long (LL) latency to get the rewards cohabitated for more than 2 weeks, in order to establish a stable hierarchy. We found that SL animals exhibited dominant behavior consistently in social competition tests [for palatable-rewards and two water competition tests (WCTs)] after hierarchy was established, indicating that individual latency to rewards predicted dominance. Moreover, because SL animals showed higher mesolimbic levels of DA than LL rats, we tested whether stimulation of mesolimbic DA neurons could affect the outcome of a social competition. Indeed, a combination of optical stimulation of mesolimbic DA neurons during individual training and during a social competition test for palatable rewards resulted in improved performance on this test.

Higher and lower status individuals’ performance goals: The role of hierarchy stability.

Compared with lower status individuals, higher status individuals are particularly likely to endorse approach (vs. avoidance) forms of motivation—notably, performance- approach goals (e.g., seeking to demonstrate superior competence) rather than perfor- mance-avoidance goals (e.g., seeking not to demonstrate inferior competence). In the present paper, we argue that this effect is likely to occur when the hierarchy is stable (i.e., in contexts in which mobility is not expected). Conversely, in unstable systems, pursuing both performance-approach goals and performance-avoidance goals might become relevant strategies, regardless of status. In two studies, performance-approach and performance-avoidance goals were measured and status was manipulated. Percep- tion of hierarchy stability was either measured (Study 1) or manipulated (Study 2). The results of both studies supported that the difference between higher and lower status individuals in terms of performance-based goal orientation only appeared in stable hierarchical systems, sustaining a view of performance-based goals as dynamic pro- cesses resulting from the position one occupies in a hierarchical system.

The origin and stability of nanostructural hierarchy in crystalline solids.

The structural hierarchy exhibited by materials on more than one length scale can play a major part in determining bulk material properties. Understanding the hierarchical structure can lead to new materials with physical properties tailored for specific applications. We have used a combined experimental and phase-field modeling approach to explore such a hierarchical structure at nanoscale for enhanced coarsening resistance of ordered γ' precipitates in an experimental, multicomponent, high-refractory nickel-base superalloy. The hierarchical microstructure formed experimentally in this alloy is composed of a γ matrix with γ' precipitates that contain embedded, spherical γ precipitates, which do not directionally coarsen during high-temperature annealing but do delay coarsening of the larger γ' precipitates. Chemical mapping via atom probe tomography suggests that the supersaturation of Co, Ru, and Re in the γ' phase is the driving force for the phase separation, leading to the formation of this hierarchical microstructure. Representative phase-field modeling highlights the importance of larger γ' precipitates to promote stability of the embedded γ phase and to delay coarsening of the encompassing γ' precipitates. Our results suggest that the hierarchical material design has the potential to influence the high-temperature stability of precipitate strengthened metallic materials.

Foraging dynamics are associated with social status and context in mouse social hierarchies.

Living in social hierarchies requires individuals to adapt their behavior and physiology. We have previously shown that male mice living in groups of 12 form linear and stable hierarchies with alpha males producing the highest daily level of major urinary proteins and urine. These findings suggest that maintaining alpha status in a social group requires higher food and water intake to generate energetic resources and produce more urine. To investigate whether social status affects eating and drinking behaviors, we measured the frequency of these behaviors in each individual mouse living in a social hierarchy with non-stop video recording for 24 h following the initiation of group housing and after social ranks were stabilized. We show alpha males eat and drink most frequently among all individuals in the hierarchy and had reduced quiescence of foraging both at the start of social housing and after hierarchies were established. Subdominants displayed a similar pattern of behavior following hierarchy formation relative to subordinates. The association strength of foraging behavior was negatively associated with that of agonistic behavior corrected for gregariousness (HWIG), suggesting animals modify foraging behavior to avoid others they engaged with aggressively. Overall, this study provides evidence that animals with different social status adapt their eating and drinking behaviors according to their physiological needs and current social environment.

Numerical simulation on phase stability between austenite and ferrite in steel films sputter-deposited from austenitic stainless steel targets

This contribution presents a theoretical discussion on phase hierarchy stability between face-centered cubic (FCC), austenite, and body-centered cubic (BCC), ferrite, lattice structures of stainless steel (SS) films that are sputter-deposited from austenitic targets under non-reactive atmospheres. Data published in literature on both phase characterization and chemical composition of diverse SS films are interpreted anew in this contribution in the light of lattice stability thermodynamic simulations. For films obtained from 304 and 316 steel targets, thermodynamic simulations predict that the ferrite phase is more stable than the austenite phase at low thermal energies. In contrast, simulations forecast thermodynamic stability at low thermal energies of the austenite phase in films that are sputtered from 330 steel targets. The criterion of lattice stability reveals that structures observed in the experiments cannot be described comprehensively by thermodynamic states where either full atomic partitioning among phases is established or zero atomic partitioning takes place. Thereby, a description of an equilibrium with incomplete atomic partitioning is proposed here, with the aim of depicting the structures reported in the literature. Such an equilibrium with incomplete atomic partitioning adequately describes the gradual destabilization of ferrite and the increased fraction of austenite (up to fully austenitic structures), when either the substrate heating is intensified, or the Ni content of the alloy is increased, with an 73Fe18Cr9Ni, wt%, initial alloy as a basis.

A Closer Look: Examining Distance within Status Hierarchies

Status hierarchies are a central part of group life. Scholars have devoted considerable attention to understanding the effects of status hierarchies. However, there is unresolved debate about the promises and perils of status hierarchies. In this symposium, we revisit a core assumption in how status hierarchies are typically conceptualized in the literature. Rather than viewing status solely in relative terms, as a rank-ordering of individuals on the basis of prestige, respect, and esteem, we introduce new theory and research that invokes the concept of status distance --- the absolute magnitude of status differences between individuals in a group. Across 5 methodologically diverse papers, we examine the individual, dyadic, and group-level effects of status distance. By exploring status distance from multiple angles, our hope is to open up new theoretical terrain and stimulate novel research questions. The contingent effects of scapegoating in work teams: The moderating role of hierarchy stability Presenter: Stuart Bunderson; Washington U. Presenter: Steven Gray; The U. of Texas at Austin Presenter: Gerben S. Van Der Vegt; U. of Groningen The interactive effect of status distance and newcomer status on willingness to help teammates Presenter: Sarah Doyle; U. of Arizona Presenter: Beth Polin; Eastern Kentucky U. Presenter: Robert B. Lount; Ohio State U. A qualitative investigation of the relationships between leaders and their second-in-commands Presenter: Benjamin Dow; The U. of Texas at Austin Perspective taking and employee deviance: The role of leaders dominance and prestige Presenter: Hemant Kakkar; London Business School Presenter: Niro Sivanathan; London Business School Do we agree on whos in charge here? Status dissensus antecedents and impact on team performance Presenter: Catarina Fernandes; Harvard Business School Presenter: Sujin Jang; INSEAD

Cluster-based efficient information dissemination in dynamic networks

Dynamic network is an abstraction of networks with frequent topology changes arising from node mobility or other reasons. In this article, we first propose a dynamic network model, named ( T, L)-HiNet, to extend existing dynamic network models with clusters. ( T, L)-HiNet includes several properties defining the stability of cluster hierarchy in a dynamic network, including cluster head set, cluster member set and the connections among them. Based on ( T, L)-HiNet, we design several hierarchical information dissemination algorithms for different scenarios of dynamics. Furthermore, we extend the ( T, L)-HiNet model and corresponding algorithms in two directions, that is, stability of cluster head set and cluster size. The correctness of our algorithms is proved rigorously, and their performance is evaluated via both numerical analysis and simulations. The results show that compared with the algorithm recently proposed by Kuhn et al., our design can significantly reduce communication cost and also time cost.

Official hierarchy and city and urban village typology established at the end of XVIII-XIX centuries

The article deals with one of the aspects of the cardinal reform of the city that took place in the reign of Catherine II. The reform of the city, taking place within the framework of the administrative and territorial reform of Catherine II, was closely related to the process of creating a network of new small provinces and the formation of a network of cities and urban settlements in each of the new entities administrative. The city network (a network of cities and urban settlements) was a complex (rather than a set) of settlements of a particular region, having (in the presentation of contemporaries) the status of the city or its official signs. In the course of its existence, a distribution of functions occurred within the network. The set of functions inherent in different urban settlements, determines their character and face in the broadest sense of the word. All functions can be conditionally divided into two groups: administrative and economic. In our study, attention was drawn to the approval of a set of administrative functions outside the city as part of the countrys spatial and settlement to the establishment of certain types of cities and urban settlements, with a set of features and responsibilities. In this case, between the types of settlements a stable hierarchy as administrative centers established. The reason for its appearance is wider than the need for formal subjection. The network of cities and urban settlements of the country, established by the beginning of the XIX century, was complex with a heterogeneous structure. It included settlements, officially called cities according to the rules of its time, and other structures that do not belong to this group. The latter also performed city functions and were considered contemporaries on a par with the official cities, separating themselves from rural settlements. The name of settlements did not always correspond to their economic quality. Along with the administrative type of cities, there were intermediate forms of urban settlements, which, according to the norms of that time, did not apply to cities (non-resident cities, supernumerary cities, settlements, small towns). In addition, archaic forms of settlements connected with cities and partly fulfilling their functions, were preserved. An important peculiarity of this historical period is the simultaneous existence of numerous and diverse forms of urban settlements including archaic ones. This circumstance is caused by the transitional nature of the time, the implementation of administrative reform, as well as the desire of the authorities to implement the process of transformation without a radical breakdown and social protest.

Stress and the stability of social systems: A review of neurophysiological research

ABSTRACTCurrent societies are characterised by unprecedented change in demographic, economic and political terms. These changes may be rather stressful, especially for those who have most to lose, that is members of (formerly) high-status groups. In this contribution, we review research on the influence of hierarchy stability on physiological stress, making a distinction between the cardiovascular correlates of negative stress (“threat”) and positive stress (“challenge”). Results from six studies reveal that when hierarchies are stable those low in rank show threat, while when hierarchies are unstable, those high in rank show threat and those low in rank show challenge. These effects occur independently of whether rank is based on power or status, or on interpersonal or inter-group comparisons. Results are discussed in terms of theories on power and identity, and implications for (interventions for) inter-group conflict and health.

The effects of high environmental ammonia on the structure of rainbow trout hierarchies and the physiology of the individuals therein

Our goals were: (i) to determine whether sublethal concentrations of water-borne ammonia would prevent the formation of a dominance hierarchy, or alter its structure, in groups of 4 juvenile trout; (ii) to investigate the behavioral and physiological responses of individuals of different social rank exposed to a concentration of ammonia that still allowed hierarchy formation. Social hierarchies were created by using a technique in which a food delivery system that created competition also served to isolate individual fish for respirometry. Groups of 4 fish were exposed to elevated ammonia (NH4HCO3) 12 h before first feeding; aggression was recorded by video camera during morning feedings. Experimental ammonia concentrations were 700, 1200 and 1500 μmol L−1 at pH 7.3, 12 °C (9.8, 16.8, and 21.0 mg L−1 as total ammonia-N, or 0.0515, 0.0884, and 0.1105 mg L−1 as NH3-N). Aggression was severely reduced by 1200 and abolished by 1500 μmol L−1 total ammonia, such that hierarchies did not form. However, groups exposed to 700 μmol L−1 total ammonia still formed stable hierarchies but displayed lower levels of aggression in comparison to control hierarchies. Exposure continued for 11 days. Physiological parameters were recorded on day 5 (end of period 1) and day 10 (end of period 2), while feeding and plasma cortisol were measured on day 11. In control hierarchies, dominant (rank 1) trout generally exhibited higher growth rates, greater increases in condition factor, higher food consumption, and lower cortisol levels than did fish of ranks 2, 3, and 4. In comparison to controls, the 700 μmol L−1 total ammonia hierarchies generally displayed lower growth, lower condition factor increases, lower O2 consumption, lower cortisol levels, but similar feeding patterns, with smaller physiological differences amongst ranks during period 1. Effects attenuated during period 2, as aggression and physiological measures returned towards control levels, indicating both behavioral and physiological acclimation to ammonia. These disturbances in social behavior and associated physiology occurred at an ammonia concentration in the range of regulatory significance and relevance to aquaculture.

Alpha male status and availability of conceptive females are associated with high glucocorticoid concentrations in high-ranking male rhesus macaques (Macaca mulatta) during the mating season

The relationship between male mating opportunities, stress, and glucocorticoid concentrations is complicated by the fact that physiological stress and glucocorticoid concentrations can be influenced by dominance rank, group size, and the stability of the male dominance hierarchy, along with ecological factors. We studied the three highest-ranking males in nine different social groups within the same free-ranging population of rhesus macaques on Cayo Santiago, Puerto Rico, during the mating season, to examine variation in glucocorticoid concentrations in relation to number of females that conceived each month, alpha status, number of adult males in a group, and male rank hierarchy stability. We found that glucocorticoid concentrations were highest in the early mating season period when more females conceived in each group and declined linearly as the mating season progressed and the number of conceptive females decreased. Alpha males had significantly higher mean monthly glucocorticoid concentrations than other high-ranking males throughout the study period. Male age, number of adult males in a group, and hierarchy stability were not significantly associated with glucocorticoid concentrations. Our findings suggest that alpha males may experience significantly higher levels of physiological stress than their immediate subordinates and that this stress coincides with the period of the mating season when most conceptions occur.

Rasch validation and comparison of Slovenian, Croatian, and Italian versions of the Mini-BESTest in patients with subacute stroke

We aimed to verify by Rasch analysis whether the Mini-BESTest, a balance measure, confirms its main psychometric properties in patients with subacute stroke undergoing rehabilitation in three different countries (Slovenia, Croatia, and Italy), and to examine the stability of item hierarchy and difficulty across the three national versions through a differential item functioning analysis. We investigated 159 patients with subacute stroke consecutively admitted to three rehabilitation facilities after screening for an intensive, tailored rehabilitation program. Balance function was tested within 36 h from admission and after ∼25 days. As no differential item functioning was found between admission and discharge data or among countries, all data were pooled. Rasch criteria for the functioning of rating scale categories were fulfilled. In terms of internal construct validity, all items except item #14 (Cognitive Get Up & Go; infit value=1.42) showed an acceptable fit to the Rasch model. The patient ability-item difficulty matching was very good. Reliability indices were high. The Principal Component Analysis of standardized residuals confirmed the unidimensionality of the test. On the basis of the item calibration, raw scores of the Mini-BESTest were transformed into linear estimates of dynamic balance and six statistically detectable levels of balance ability were defined. Good psychometric features of the Mini-BESTest were confirmed. The three different national versions showed stability in item hierarchy, indicating equivalence of their cross-cultural adaptations. Problems with item #14 in these patients warrant further study.

Хакасы в условиях глобализации: ментальные деформации

В статье анализируются деформации, произошедшие в менталитете хакасов, тюркоязычного этноса Южной Сибири. Авторами менталитет понимается как обладающий внутренним единством способ бытия народа в мире для сохранения этноса как целостности через организацию знаний в этническую картину мира; через создание устойчивой иерархии этнически оформленных потребностей, интересов и ценностей; через формирование системы авто- и гетеростереотипов; через устойчивые формы поведения в различных ситуациях. В результате действия внешних и внутренних факторов менталитет, исторически устойчивый феномен, может подвергаться деформациям. Последние нами понимаются как изменение базовых элементов менталитета (потребности, интересы, ценности), приводящие к обратимым или необратимым для народа изменениям.Для фиксации ментальных деформаций у хакасов в статье осуществлено сравнение традиционных этнических ценностей и современных, осуществленных, в первом случае в середине 1990-х на основе междисциплинарного исследования традиционного мировоззрения этноса, во втором — как результат социологического опроса 2015 г.Анализ показал, что иерархия базовых традиционных ценностей «родная земля», «хакасский народ», «семья» остается таковой для этнических акторов как ресурс сохранения и развития народа и в условиях глобализации. Однако социологическое исследование зафиксировало изменение конфигурации системы ценностей в целом среди хакасского народа. На первое место выходит ценность «семья», что отражает действие общеисторической закономерности: этнос, находящийся в состоянии кризиса, возвращает базовые, проверенные временем, социальные институты (семья, род). Последние призваны сохранить этнос как биопсихосоциальную общность.

Keeping Minorities Happy: Hierarchy Maintenance and Whites' Decreased Support for Highly Identified White Politicians.

We test the hypothesis that, to avoid provoking minorities, Whites will withhold their support for White political candidates who are highly identified with their race. In Study 1, we found that White Republicans were less supportive of White candidates the higher the perceived White identity of the candidate due to beliefs that such candidates would provoke racial minorities. In Study 2, we replicated this effect with a manipulation of candidates' White identity. Study 3 found that Whites reported less support for high-identity candidates when they were led to believe that the hierarchy was unstable rather than stable. Consistent with our hypothesis that those who have the most to lose are most likely to avoid provoking minorities, in Study 4, we found that Whites with high subjective socioeconomic status (SES) varied their support for provocative White candidates as a function of hierarchy stability, whereas those with low subjective SES did not.

Social organization and endocrine profiles of Australoheros facetus, an exotic freshwater fish in southern Portugal

Australoheros facetus is a neotropical cichlid and an exotic species in the Guadiana and Odelouca basins (Southern Portugal). In this research, we aimed to characterize the main behavioural patterns and circulating hormones, 17β-estradiol (E2) for females, and testosterone, 11-ketotestosterone (11KT) and cortisol for both sexes, during the formation of social groups, a crucial step in the life-history of A. facetus. A pair-breeding strategy with territorial behaviour and aggressive interactions was found, with a positive correlation between dominance and size for both sexes. There were no significant differences between non-territorial and territorial individuals in the baseline levels of hormones, but 11KT was higher in males when they became territorial, as E2 for territorial females, while there was no clear pattern for testosterone. In contrast, cortisol was higher in non-territorial males and correlated negatively with social dominance. These results suggest that size is the main driver for social dominance and that formation of stable hierarchies result in higher circulating 11KT and lowers stress in territorial males. Related to A. facetus’ behaviour, aggressiveness and biparental care may be an advantage during the invasion process of A. facetus, facilitating colonization of new habitats.