Neutral Arena Research Articles

Effect of gonadal hormones and sexual experience on vocalizations and behavior of male bank voles (Myodes glareolus)

This study investigated the influence of gonadal hormones and sexual experience on behavior, especially vocalizations, of male bank voles ( Myodes glareolus (Schreber, 1780)) during same-sex encounters in a neutral arena. Interactions within pairs of castrated males, castrated but testosterone-treated males, and sham-operated intact males were studied in the first experiment and within pairs of sexually experienced males and sexually inexperienced males in the second experiment. Castration reduced the number of ultrasonic vocalizations emitted and androgen treatment restored it to levels seen in intact males. Ultrasounds were emitted more frequently during amicable encounters than during aggressive ones, but ultrasonic calling was reduced during interactions between sexually experienced males, possibly because of the high level of aggression seen in such encounters. In contrast, audible sounds were associated with aggressive behavior and were positively affected by social experience, but they were not testosterone dependent. Neither testosterone nor sexual experience appeared to have any effect on the spectral and temporal characteristics of either audible or ultrasonic calls. The results indicate that emission of ultrasounds during same-sex encounters of male bank voles is regulated by hormonal and social factors and seems to be correlated with type of behavior shown.

Evidence for residence-induced enhancement of aggressiveness in the non-territorial pig

Wild pigs ( Sus scrofa) are only territorial during the peri-parturient period and when young compete for access to teats. In other species, territorial defence is affected by contextual factors including resource quality. Territoriality could be stimulated in species such as pigs by artificial mixing and intensive housing. Test pigs were introduced to a novel opponent for 5 min on consecutive days (days 1 and 2) in two locations (home pen of the test pig (P) or a neutral arena (A)) in a randomised block design. On day 1, animals tested in their home pen were more likely to initiate an escalated attack (proportion of pigs 0.43 vs 0.19 in the pen and neutral arena, P < 0.01). A shorter latency to attack on day 2 in the PP (pen on both days) and PA (pen then arena) treatments suggested that a previous encounter in the home pen affected later aggressiveness. The time spent engaged in non-escalated aggressive behaviours (parallel walking, pushing, knocking and biting) with the opponent was similar in the two environments. Some capacity for territorial defence through escalated aggression and the enhancement of subsequent aggressiveness appears to occur in pigs when in their home pen. The suppression of escalated aggression in the neutral arena by handling and environmental exploration cannot be discounted, but appears not to have affected the occurrence of non-escalated aggression. The mixing of pigs in an occupied pen is likely to enhance escalated aggression from the occupants without reducing that from the intruders and should be avoided.

Intraspecific Behavior of Heather Voles (Phenacomys intermedius)

Very little is known about the social behavior of Heather Voles (Phenacomys intermedius), mainly because they are difficult to trap and maintain in captivity. We were able to maintain individuals in the laboratory and observe dyadic interactions among adult males and females, as well as related and unrelated juveniles, in a neutral arena. Overall, Heather Voles were very docile compared to other microtine species observed in captivity. There were no amicable behaviors observed, and the majority of encounters consisted of neutral egocentric actions. Males and females showed very similar levels of aggression in intrasexual encounters, although encounters between males contained more overt fighting behaviors. Male-female encounters contained the most aggressive behaviors (especially chasing), with a large proportion of those behaviors likely being the male attempting to copulate with the female, and the female resisting. No differences in aggressive behaviors were observed between related and unrelated juveniles.

Parent–offspring recognition in Brandt's voles, Lasiopodomys brandti

We investigated social interaction behaviour (amicable versus agonistic) to evaluate parent–offspring recognition in male and female Brandt's voles. We first examined whether the parents were able to distinguish their own familiar related offspring at the age of weaning from unfamiliar unrelated offspring. Both male and female parents, when encountering unfamiliar unrelated juveniles in a neutral arena, showed significantly more agonistic behaviour than when encountering their own familiar offspring, which suggested that adult Brandt's voles might be able to discriminate their own familiar descendants from unfamiliar unrelated ones. Second, we used cross-fostering to investigate the underlying parent–offspring recognition mechanism. Both males and females showed more amicable behaviour and less agonistic behaviour to familiar related offspring than to unfamiliar related offspring. Males showed significantly more amicable behaviour to familiar related offspring than to unfamiliar related offspring, and significantly less agonistic behaviour to familiar unrelated offspring than to unfamiliar unrelated offspring. Remarkably, females showed less agonistic behaviour to familiar related offspring than to unfamiliar related offspring. Furthermore, males and females did not show a significant difference in amicable or agonistic behaviour between familiar related and familiar unrelated offspring or between unfamiliar related and unfamiliar unrelated offspring. Our results suggest that the mechanism of parent–offspring discrimination in Brandt's voles could be familiarity.

Standardization as open innovation: two cases from the mobile industry

PurposeThe purpose of the paper is to introduce standardization as a neutral arena for open innovation. The aim is to show that different policies towards open membership in standardization initiatives lead to different open innovation processes.Design/methodology/approachTwo cases are used to illustrate the differences in open innovation processes. The cases are the Android mobile operating system and the service platform developed by the Open Mobile Alliance. The core process types introduced by Gassmann and Enkel are used to show the different open innovation approaches.FindingsBoth cases use open innovation to create standards. Open membership leads to a coupled process, while a more restricted membership gives separate inside‐out and outside‐in processes. The case lead by established firms in the industry has a process where radical innovations are introduced early in the process, while the case lead by newcomers has a process where radical innovations are introduced late in the process. The two cases have different approaches towards commercialization of the products. Android relies on third‐party developers, while the Open Mobile Alliance relies on their own members.Research limitations/implicationsThe cases are from the telecommunication sector and based on standardization of large technical platforms. The findings might not be the same for other sectors.Originality/valueThe paper establishes open innovation as a neutral arena for open innovation outside the domain of any single firm. It shows how the openness towards membership influences the choice of open innovation processes.

Teaching the Nation: Religious and Ethnic Diversity at State Schools in Britain and the Netherlands

Background/ContextThe article presents the outcomes of international comparative anthropological (qualitative) research on multiculturalism, citizenship, and nation building in schools in Paris, Berlin, London, and Rotterdam. The findings presented here are based on fieldwork carried out over a period of 1 year at secondary schools in the Dutch city of Rotterdam and in London. The project has demonstrated a close relationship between national specific modes and trajectories of integration and the ways in which the schools deal with diversity.Purpose/Objective/Research Question/Focus of StudyThis article addresses the growing diversity in religious and ethnic backgrounds among students at primary and secondary schools in Western Europe. The debate about the place of religion in school has gained momentum after the arrival of large numbers of migrants, especially those with a “new” religious background, such as Islam. Their presence challenges existing arrangements and privileges and puts matters that were previously taken for granted back on the agenda. Religion and ethnicity at school touch on a fundamental issue, namely the place of state schooling in the making of modern nation-states. Several issues need to be taken into account: To what extent is religion a legitimate moral resource? Why should one learn about religion, and who should teach it to whom? Is it more important to get religious nurturing or to study the plurality of different belief systems? Should the school accommodate religious and cultural diversity, or should it rather be a neutral arena that deliberately disregards this diversity? These questions do not arise together in one package but present themselves in fragmented, occasional, and contingent ways.SettingThe data were collected during intensive ethnographic fieldwork in four secondary schools in Neuköln (Berlin), Saint Denis (Paris), Crooswijk (Rotterdam), and Haringey (London).Research DesignQualitative fieldwork, case study in secondary schools.Conclusions/RecommendationsThe outcomes of the study demonstrate that although schools are, to a large extent, unique settings that cannot be lumped together, they are crucial sites where principles of national civil incorporation are transmitted to pupils. Although the two schools described in this article resemble each other to a large degree in terms of ethnic composition of the neighborhood, problems faced, and policies adopted by the school board, they each have their specific way of dealing with ethnic and religious diversity. These ways reflect national specific political culture in each of the two countries.

To fight or not to fight: context-dependent interspecific aggression in competing ants

Animals assess many factors when choosing how aggressively to behave during interspecific competitive interactions. Aggressive behaviour can help win resources, but it can also be costly. Here we tested how context such as competitor familiarity, habitat type and resource value affect competitive behaviour using two ant species, Formica xerophila and F. integroides. We found that competitive encounters within an individual's territory yielded more aggressive interactions than encounters in a neutral arena, and aggression towards competitors increased with resource value. Using a recently developed design combining behaviour assays between live ant dyads and ants paired with glass beads chemically resembling competitors, we isolated an individual's behaviour during an encounter to show that its behaviour can be significantly affected by the behaviour of its competitor during the interaction. Furthermore, we determined that context can affect each species differently, and that these differences are consistent with differences in overall fighting abilities. Formica integroides from trees (but not from nests) behaved differently towards live and artificial F. xerophila. Formica integroides are behaviourally dominant, which facilitates a strategy wherein individuals aggressively defend the nest but reciprocate the behaviours of their opponents (showing an interspecific Tit-for-Tat strategy) when defending less valuable locations. Formica xerophila are generally submissive, which favours a highly context-dependent strategy. In particular, F. xerophila discriminate between familiar and unfamiliar F. integroides, and behave more aggressively towards foreign competitors than towards neighbouring competitors. Differences between species’ behaviours suggest that these interspecific interactions are dynamic context-dependent associations that cannot be reduced to a static dominance hierarchy.

Popular Constitutionalism's Hard When You're Not Very Popular: Why the ACLU Turned to Courts

Through a case study of the early American Civil Liberties Union (ACLU), this article examines the empirical ramifications of constitutional scholars' recent exhortations to “take the Constitution away from the courts” in order to promote democratic deliberation about constitutional meaning. While it is now one of the most prominent examples of a litigation-based interest group, the ACLU began its existence demonstrating a commitment to constitutionalism outside the courts. Through coding a decade's worth of meeting minutes and examining archival sources, I demonstrate that the ACLU's mounting unpopularity rendered extrajudicial politics impossible, precipitating the ACLU's shift toward litigation. The ACLU's move toward litigation, despite its early devotion to political activism outside the courts, suggests that it is not always possible for political actors to make constitutional arguments without courts. Furthermore, the ACLU's use of courts to publicize and dramatize its constitutional arguments demonstrates that litigation may actually promote popular deliberation about constitutional meaning. These political realities both highlight and contradict two empirical assumptions underlying arguments about the normative desirability of restricting courts' involvement in constitutional politics. First, the state is not a neutral arena in which all political actors are equally free to pursue their constitutional visions through majoritarian processes. Second, courts may facilitate (rather than hinder) popular deliberation about constitutional questions.

Affiliation in Four Echimyid Rodent Species based on Intrasexual Dyadic Encounters: Evolutionary Implications

AbstractIn this work we explored the evolution of sociality in cursorial echimyids by comparing affiliation among three species of Trinomys and one species of Thrichomys. We captured specimens of Trinomys yonenagae, Trinomys albispinus minor, and Thrichomys apereoides in areas of the Brazilian semiarid Caatinga, and Trinomys iheringi denigratus in one area of Atlantic Forest. For each species, we recorded 12 intra‐sexual dyadic encounters in a neutral arena (six between males and six between females) in order to test the hypothesis that species and sex influence level of affiliation. This response variable was assessed based on an affiliation index, calculated as the proportion of the total number of affiliative behaviors to the total number of social behaviors exhibited by the dyad during each encounter. Hypothesis test was performed by means of a parametric two‐way anova. The test was able to detect significant differences only among species, not among sexes. Trinomys yonenagae was the most affiliative species, while T. apereoides and T. albispinus minor were the most agonistic ones. Trinomys iheringi denigratus showed an intermediate pattern. We suggest, based on out‐group comparison, that affiliation in Trinomys increased in the lineage containing T. iheringi denigratus and T. yonenagae and that higher affiliation in the last species can be adaptive to the life in the desert‐like habitat where it lives.

Inbreeding and competitive ability in the common shrew (Sorex araneus)

Common shrews (Sorex araneus) maintain a foraging territory for most of their immature life. Possessing a high-quality territory is vital for overwinter survival in the harsh boreal climate, and hence, competitive ability in territorial disputes is expected to be an important component of individual fitness. To test possible association between individual inbreeding and fitness, we used neutral arena trials to assess the competitive performance of young common shrews. The experiment involved pairs of individuals originating from small island populations, where breeding must often occur between related individuals, and from large outbred mainland populations. The percentage of neutral arena tests that an individual won was highly significantly explained by internal relatedness, a surrogate measure of individual inbreeding, measured using ten microsatellite markers. Body size, sex, learning, and population type (mainland vs island) made no significant contributions. Even a low level of individual inbreeding may lead to significant adverse consequences in multiple territorial contests, which may represent a significant cause of inbreeding depression in many wild vertebrate populations.

Reduced aggression in mice lacking GABA transporter subtype 1

Dysregulation of the brain GABAergic system has been implicated in the pathophysiology of violence and aggression. As a key regulator of central GABAergic activity, dysfunction of the GABA transporter subtype 1 (GAT1) represents a potential mechanism mediating pathologic aggression. We provide evidence that GAT1-/- mice and GAT1+/- mice exhibit lower aggressive behavior both in home cage resident-intruder test and neutral arena resident-intruder test, compared to wild-type mice (GAT1+/+). The pharmacologic effects of the GAT1 inhibitor, tiagabine and the GABA(A) receptor antagonist, bicuculline have been assessed in GAT1+/+ mice: tiagabine inhibits attacks but bicuculline induces attacks. Compared to GAT1+/- and +/+ mice, the GAT1-/- mice displayed a normal circadian pattern of home cage activity, but more activity overall. Meanwhile, reduced testosterone concentration was found in GAT1-/- mice compared to GAT1+/+ mice but not in GAT1+/+ mice treated with tiagabine, suggesting that testosterone is not directly involved in GAT1 mediated aggressive behavior regulation. These results showed that GAT1 is an important target involved in the regulation of aggressive behavior in mice, and long-term dysfunction of GAT1 may also result in the alteration of testosterone secretion.

Seasonal changes in chronic social interactions and physiological states in female rat-like hamsters ( Tscheskia triton)

We examined the behavioral characteristics and physiological states related to solitary lifestyle and dominant–subordinate relationships in female rat-like hamsters ( Tscheskia triton), formerly known as Cricetulus triton. Wild adult hamsters were captured and caged singly in the laboratory during the non-breeding and breeding seasons. The experimental hamsters were subjected to 5 min staged dyadic encounters every day for 28 consecutive days by pairing two unfamiliar and weight matched females in a neutral arena. Aggressive behavior, defense and flank marking were quantified everyday within the first week and once each week during the last 3 weeks. Animals were then autopsied and their physiological and reproductive state assessed. Our results suggested that dominant–subordinate relationships could be established especially in non-breeding conditions, where the dominant displayed higher aggression and flank marking, and lower defense than its opponent. The breeding females followed this pattern except there was no difference in aggressive behavior, between the partners. The repeated encounters did not appear to reduce aggression or lead to amiable behavior or bonding. At the end of the experiment breeding females exhibited higher levels of serum estradiol, progesterone and corticosterone than non-breeding females. Both dominant and subordinate females in non-breeding condition had atrophied ovaries and uteri, whereas both dominant and subordinate females in breeding condition had hypertrophied ovaries and uteri. Non-breeding females possessed heavier and thicker flank glands than breeding females did. Dominant females displayed longer or thicker flank glands than subordinate did. Thus, our data suggest that the behavioral traits observed in our experiment support the solitary lifestyle of adult female rat-like hamsters and physiological state show some differences between social ranks or in both seasons.

Social Dominance among Male Meadow Voles is Inversely Related to Reproductive Success

AbstractIntrasexual selection can occur through direct aggressive interactions between males for access to females. We tested the relationship between social dominance and male reproductive success among meadow voles, Microtus pennsylvanicus. Dominance ranks of wild‐caught males were determined using neutral arena trials, with the winner of two of three trials considered dominant. These males were then released into field enclosures and allowed to visit females housed in nestboxes for 8 wk, and males’ home range sizes were determined using weekly grid trapping. Male reproductive success was determined using molecular paternity analysis (six microsatellite primers) for all pups born during the field experiment. Males with higher dominance ranks had larger home ranges. However, male dominance rank was not predictive of the number of total visits to females’ nestboxes or the number of visits to each male's most frequently visited nestbox. Males that made more visits to nestboxes sired more litters. Males that had higher dominance ranks sired fewer litters. These results suggest that there is a reproductive disadvantage to having higher dominance rank among male meadow voles.

Litigation as Political Participation

Courts were commonly regarded as a neutral arena to settle disputes between rivals who cannot solve their differences through other means of dispute resolution. In recent years however, greater attention is drawn to the role played by courts within the political process itself. This article sets out to examine the role of public litigation in the Israeli High Court of Justice as a vehicle of political participation. We will argue that the Court has become an avenue for: a) participation in decision-making processes, b) communication with official authorities, and c) protestation against these very same authorities.

Kin recognition and the paradoxical patterns of aggression between colonies of a Mojave desert Pheidole ant

Populations of the desert seed-harvesting ant Phei- dole xerophylla are often characterized by high nest density leading to competitive interactions between foragers from different nests. We investigated the inter-nest aggression, spatial distribution and genetic structure of a P. xerophylla population of the Mojave Desert in Southern California. Inter-nest aggression was quantifi ed by standardized staged encounters in a neutral arena. Genetic relatedness within nests and relatedness between nests were calculated using al- lelic frequencies at four microsatellite-DNA loci. We found a bimodal distribution of inter-colony aggression levels with a fi rst mode at low aggression levels and another mode at much higher aggression levels. Inter-colony aggression levels were largely non-transitive. No effect of geographical distance on inter-nest aggression levels was detected. De- spite high amounts of variation in inter-colony relatedness (-0.24 to 0.37) this variable did not correlate with the level of aggression between nests. Intra-nest relatedness ranged from 0.40 to 0.75 and close inspection of worker genotypes within colonies revealed a high proportion of polygynous colonies or a mixture of polygyny and polyandry. Aggression levels among nests was found to decrease with increasing intra-nest relatedness. These results do not support the idea that ag- gression is modulated by a nestmate recognition mechanism based on overall genetic similarity. Instead, the absence of transitivity found in inter-colony aggression and bimodal distribution of aggression levels are compatible with a com- mon label acceptance model of nestmate recognition and suggest that label diversity may be encoded by a limited number of loci.

Femoral secretions and copulatory plugs convey chemical information about male identity and dominance status in Iberian rock lizards (Lacerta monticola)

Socially dominant males often signal their status to rival males and/or females. We tested the hypotheses that Lacerta monticola femoral gland secretions and copulatory plugs convey chemical information about male identity and dominance status. We estimated male dominance status by staging male–male agonistic encounters in a neutral arena. We then conducted two experiments to compare male tongue-flick behavior toward chemical stimuli consisting of cotton swabs bearing (1) deionized water (control), the lizard’s own femoral secretions, and the femoral secretions of another male and (2) phosphate-buffered saline solution (control), the lizard’s own plug products, and the plug products of another male. Results indicate that males discriminated their own femoral secretions and plugs from those of other males. They also discriminated morphological attributes of other males that were associated with dominance status based on chemical cues arising from femoral secretions and discriminated the dominance status of other males based on chemical cues arising from the plugs. Femoral secretions that convey information about male identity and dominance status may be hypothesized to function in the establishment of L. monticola dominance hierarchies through scent-marking of territories. We suggest that copulatory plugs and femoral secretions may allow males to scent-mark the female body and postulate that this behavior may influence male and female reproductive decisions under selective pressures of sperm competition.

Role of V1a vasopressin receptors in the control of aggression in Syrian hamsters

The present study investigated the hypothesis that social isolation increases aggression by increasing the number of V1a vasopressin receptors in the anterior hypothalamus (AH). Male hamsters were randomly assigned to a group that was allowed to interact with a small nonaggressive hamster three times each week for 3 weeks (socially experienced) or to a group that did not interact socially with other hamsters (social isolates). On the final day of the experiment, hamsters in both groups were placed in a neutral arena with a small, nonaggressive intruder, and agonistic behavior was scored for 10 min. In social isolates, the duration of aggression and the number of attacks were significantly greater than in socially experienced hamsters. There were no significant between-group differences in the latency to the onset of aggression, the number of flank marks or in the duration of defensive/submissive, social or nonsocial behavior. The amount of V1a receptor binding was significantly greater in the AH, the paraventricular nucleus of the hypothalamus and the lateral hypothalamus in the social isolates than in the socially experienced hamsters. The amount of V1a receptor binding was significantly greater in the central amygdala of socially experienced hamsters than in socially isolated hamsters. Serum concentrations of testosterone were significantly higher in the socially experienced hamsters than in social isolates. These data support the hypothesis that social isolation increases aggression by increasing the number of V1a vasopressin receptors in the AH.

Electric organ discharge frequency jamming during social interactions in brown ghost knifefish, Apteronotus leptorhynchus

In most communication systems, animals avoid jamming when similar signals from two individuals might overlap and cause interference. Most species of wave-type electric fish avoid jamming by shifting their electric organ discharge (EOD) frequencies away from those of conspecifics or away from mimics of sine wave EOD frequencies presented in playback experiments. Both male and female brown ghosts, however, appear to intentionally jam rivals during competitive interactions if the rival has a higher EOD frequency. We studied this behaviour in competitive interactions between two fish in a neutral arena, and in playback studies with single fish in resident–intruder and neutral arena models. During competitive interactions, females jammed the rival's EOD signal only when the rival's EOD frequency was within ∼30 Hz of their own EOD frequency, whereas males tried to jam EOD signals of rivals that were 70 Hz higher than their own EOD frequency. In the resident–intruder model experiment, fish tended to raise their EOD frequencies to within potential jamming range in response to a simulated intruder with a higher EOD frequency than their own. In a neutral arena model, fish directed the most aggressive attacks in response to simulated rivals with lower EOD frequencies, yet were less likely to attack the playback device if it played a frequency elevation that mimicked a fish with a lower EOD frequency attempting to jam them. This is the first evidence that electric fish may actively use jamming as an aggressive behaviour.

Behavioural mechanisms of conflict avoidance among shrews

Stable co-existence of similar species should be facilitated by mechanisms impairing, besides exploitative, interference competition. We investigated avoidance of intra- and interspecific conflicts in a four-species community of shrews [Sorex minutus Linnaeus, 1766,S. araneus Linnaeus, 1758,Neomys anomalus Cabrera, 1907, andN. fodiens (Pennant, 1771)], using the method of dyadic encounters in a neutral arena. We tested whether the use of passive (habituation, reduction of mobility, increase of inter-individual distance, and stillness) and active (‘to-and-fro’ and ‘keeping distance’ behaviours) forms of conflict avoidance depends on species, size or domination rank. The duration of conflicts was positively correlated with mobility and negatively with inter-individual distance, whereas it was unrelated to time of stillness and the active forms. The repertoire of conflict avoidance mechanisms was not species-specific and the display of these mechanisms depended rather on the size and domination rank of animals participating in a given interaction. In contrast to rodents, shrews did not avoid conflicts by the most passive forms: freeze and stillness reactions. All other forms were used with a higher or lower efficiency by all species. However, consistent with our predictions, large shrews (asN. fodiens) used mainly the passive mechanisms of conflicts avoidance (‘wait-and-see’ strategy), whereas small shrews (asS. minutus) invest proportionally more time in active forms (‘escape’ strategy).

Pair housing affects anxiety-like behaviors induced by a social but not by a physiological stressor in male Swiss mice

The role of pair housing in the modulation of anxiety-like behaviour in socially and physiologically stressed mice was investigated. The protocol of psychosocial stress consisted of submitting male adult mice to daily social confrontation with a male conspecific for a period of thirteen days. In an attempt to study a possible effect of pair housing as a social support, each male mouse was housed with a female throughout the period of experimentation, except during the agonistic interactions. As a physiological stressor, 10 9 sheep red blood cells (SRBC)/ml were injected intraperitoneally on the 1st and 7th days of the experiments. The respective control groups were as follows: non-socially stressed, non-pair housed and saline-injected mice. The humoral immune response was analysed by haemagglutination assay. The level of anxiety-like behaviours was measured in the elevated plus-maze test on the 13th day of the experiment. As a result, no significant changes in humoral immunity to SRBC were observed in mice subjected to social confrontation in a neutral arena as compared to non-socially stressed mice. As a consequence, no effect of pair housing on humoral immunity to SRBC could be evaluated. Concerning the effects of pair housing on the anxiety-like behaviours, it was possible to demonstrate that the pair housing proved to be effective in modulating anxiety-like behaviour, although in the stressed groups the percentage of time in the open arms and the time in risk assessment did not change in a symmetrical opposite form, as expected. The physiological stressor induced an anxiety-like behaviour that was not reversed by the pair housed condition. This suggests that different types of stressors activate different neural and peripheral pathways, which may or may not be modulated by pair housing, a finding that deserves our attention as a way to better understand the mechanisms that influence adaptations to stress.