Lack Of Aggression Research Articles

Behavioural and functional evidence revealing the role of RBFOX1 variation in multiple psychiatric disorders and traits

Common variation in the gene encoding the neuron-specific RNA splicing factor RNA Binding Fox-1 Homolog 1 (RBFOX1) has been identified as a risk factor for several psychiatric conditions, and rare genetic variants have been found causal for autism spectrum disorder (ASD). Here, we explored the genetic landscape of RBFOX1 more deeply, integrating evidence from existing and new human studies as well as studies in Rbfox1 knockout mice. Mining existing data from large-scale studies of human common genetic variants, we confirmed gene-based and genome-wide association of RBFOX1 with risk tolerance, major depressive disorder and schizophrenia. Data on six mental disorders revealed copy number losses and gains to be more frequent in ASD cases than in controls. Consistently, RBFOX1 expression appeared decreased in post-mortem frontal and temporal cortices of individuals with ASD and prefrontal cortex of individuals with schizophrenia. Brain-functional MRI studies demonstrated that carriers of a common RBFOX1 variant, rs6500744, displayed increased neural reactivity to emotional stimuli, reduced prefrontal processing during cognitive control, and enhanced fear expression after fear conditioning, going along with increased avoidance behaviour. Investigating Rbfox1 neuron-specific knockout mice allowed us to further specify the role of this gene in behaviour. The model was characterised by pronounced hyperactivity, stereotyped behaviour, impairments in fear acquisition and extinction, reduced social interest, and lack of aggression; it provides excellent construct and face validity as an animal model of ASD. In conclusion, convergent translational evidence shows that common variants in RBFOX1 are associated with a broad spectrum of psychiatric traits and disorders, while rare genetic variation seems to expose to early-onset neurodevelopmental psychiatric disorders with and without developmental delay like ASD, in particular. Studying the pleiotropic nature of RBFOX1 can profoundly enhance our understanding of mental disorder vulnerability.

Erupted complex odontoma – An uncommon case report with literature review

Odontomas are categorised into mixed odontogenic tumor that originates ecto-mesenchymally and made up of mineralised tissue. Hamartoma is the most frequent benign tumour with an odontogenic aetiology. It is distinguished by its sluggish growth and lack of aggression. "Erupted odontomas" are those that erupt into the oral cavity and are uncommon. They are usually noticed in regular radiography and can be caused by a variety of factors, including trauma, genetic mutations, or infection. They are categorised into complex and compound types. Erupted Complex Odontomas are rarely ensued into the oral cavity. The present case report is of such unusual erupted complex odontoma, where 17-year-old male patient reported with history of pus discharge from the left side of the face. This report is of clinical importance because it was associated with impacted tooth & agenesis of adjacent molar tooth which is usually rare. We provide clinical and radiographic findings as well as treatment for a unique instance of a massive erupted complicated odontoma in the maxilla.

Divide and conquer: Multicolonial structure, nestmate recognition, and antagonistic behaviors in dense populations of the invasive ant Brachymyrmex patagonicus.

The ecological success of ants has made them abundant in most environments, yet inter‐ and intraspecific competition usually limit nest density for a given population. Most invasive ant populations circumvent this limitation through a supercolonial structure, eliminating intraspecific competition through a loss of nestmate recognition and lack of aggression toward non‐nestmates. Native to South America, Brachymyrmex patagonicus has recently invaded many locations worldwide, with invasive populations described as extremely large and dense. Yet, in contrast with most invasive ants, this species exhibits a multicolonial structure, whereby each colony occupies a single nest. Here, we investigated the interplay between genetic diversity, chemical recognition, and aggressive behaviors in an invasive population of B. patagonicus. We found that, in its invasive range, this species reaches a high nest density with individual colonies located every 2.5 m and that colony boundaries are maintained through aggression toward non‐nestmates. This recognition and antagonism toward non‐nestmates is mediated by chemical differentiation between colonies, as different colonies exhibit distinct chemical profiles. We highlighted that the level of aggression between colonies is correlated with their degree of genetic difference, but not their overall chemical differentiation. This may suggest that only a few chemical compounds influence nestmate recognition in this species or that weak chemical differences are sufficient to elicit aggression. Overall, this study demonstrates that invasive ant populations can reach high densities despite a multicolonial structure with strong aggression between colonies, raising questions about the factors underlying their ecological success and mitigating negative consequences of competitive interactions.

Using Behavioral Experimentation to Understand the Social Structure of the Little Fire Ant (Wasmannia auropunctata) in Florida

Wasmannia auropunctata (LFA) is a small, yellow ant that is native to the Central and South America that has become a globally invasive species by acting as an agricultural pest in addition to being ecologically destructive in non-native regions. One trait thought to contribute to successful invasion of ants is unicoloniality, which is characterized by lack of aggression among workers and queens from different colonies. This results in colonies becoming effectively borderless, expanding as a single, massive colony across large geographic distance. These ants are known to be unicolonial in some parts of their range, but no studies to date have assessed unicoloniality in Florida populations. To determine whether LFA populations across Florida were members of a unicolonial lineage, we carried out integration trials using 27 colonies from 6 sites in 3 Florida counties. Approximately 20 workers from different colonies were placed together in an arena; after 24 hours they were evaluated to determine whether or not they integrated. Out of a total of 42 trials, 17 (40%) resulted in full integration and 25 (60%) did not. Colonies that were collected within 9 km of each other integrated, and ants from colonies beyond that distance did not integrate. These results suggest that the little fire is not unicolonial in Florida on a large scale, but perhaps on a smaller scale. Future studies should attempt to use colonies from more counties and incorporate genetic data to determine relatedness among these ants.

Expression Patterns of Serotonin Receptors 1А and 7 in the Brain of Rats with Genetically Determined Fear-Induced Aggressive Behavior or the Lack of Aggression

Abstract—Serotonin receptors of subtype 1А (5-HT1A) are involved in the regulation of aggressive behavior. New data show that 5-HT1A receptors are capable of heterodimerization and antagonistic interaction with type 7 serotonin receptors (5-HT7); hence, it is important to study the involvement of 5-НТ7 receptors in aggressive behavior. Specifically, it is necessary to study the patterns of co-expression of 5-НТ1А and 5-НТ7 receptors in the brains of animals that differ in the degree of genetically defined aggression. In this paper, we have studied the expression of serotonin 5-НТ1А and 5-НТ7 receptors in several cerebral structures of rats with genetically defined aggressive behavior or the lack of aggression. We have revealed significant changes in the expression of these receptors both at mRNA and receptor protein levels. Of particular interest is the changes in the levels of the membrane protein of 5-НТ1А and 5-НТ7 receptors in the midbrain and hippocampus of aggressive rats. A decrease in the level of 5-НТ1А receptors in the midbrain is associated with an increase in the level of this receptor in the hippocampus; meanwhile, the level of 5-НТ7 receptor is increased in the midbrain and decreased in the hippocampus of aggressive rats compared to tame animals. These data indicate interaction between 5-НТ7 and 5-НТ1А receptors. In addition, the expression of 5‑НТ7 receptors is increased in the frontal cortex and the mRNA level of the 5-НТ7 receptor gene is decreased in the hypothalamus of aggressive rats compared to tame animals. Therefore, significant changes in the expression of 5-НТ7 receptors in the brain of rats selected for a high level of fear-induced aggression towards humans have been revealed for the first time. Genotype-dependent peculiarities of combined expression of 5-НТ1А and 5-НТ7 receptors have been revealed in the investigated brain structures. Our data suggest that interaction between 5-НТ1А- and 5-НТ7-receptors may be an important factor in the regulation of genetically defined aggression.

A Livestock Guardian Dog by Any Other Name: Similar Response to Wolves Across Livestock Guardian Dog Breeds

Nonlethal tools for reducing livestock depredations, such as livestock guardian dogs (LGDs; Canis familiaris), reduce lethal management of livestock predators and have been widely adopted by domestic sheep (Ovis aries) producers in the United States. However, compared with their success in reducing coyote (Canis latrans) depredations, commonly used LGD breeds appear less effective against wolves (Canis lupus). With more than 30 distinct LGD breeds found throughout the world, certain breeds may be more effective at deterring specific threats. We compared LGD breeds commonly used in the United States, collectively called whitedogs, with three European breeds selected for boldness toward carnivores, history of use in areas with wolves, lack of aggression toward humans, and size. We collected data on LGD behavior with sheep herds in Idaho, Montana, Oregon, Washington, and Wyoming in 2015 and 2016. We also developed a test to examine LGDs’ response to a simulated encounter with a wolf while on summer grazing range. Results from generalized linear mixed models of proportion of time spent in a given behavior indicate that few significant behavioral differences exist among tested breeds. Kangals tended to be more investigative when engaging a decoy, karakachans more vigilant, and transmontanos more able to decipher a threatening from unthreatening stimulus. Transmontanos also spent less time scanning than whitedogs, and there was a marginally significant effect of karakachans moving more than whitedogs. While these subtle behavioral differences may help livestock producers make tailored decisions in choosing the appropriate LGD for their needs and circumstance, our results suggest that behavioral differences among breeds may be less common than often suggested.

Identifying factors associated with the discharge of male State patients from Weskoppies Hospital.

BackgroundDesignated psychiatric facilities are responsible for the care, treatment and reintegration of State patients. The necessary long-term care places a considerable strain on health-care resources. Resource use should be optimised while managing the risks that patients pose to themselves and the community. Identifying unique factors associated with earlier discharge may decrease the length of stay. Factors associated with protracted inpatient care without discharge could identify patients who require early and urgent intervention.AimWe identify socio-economic, demographic, psychiatric and charge-related factors associated with the discharge of male State patients.MethodsWe reviewed the files of discharged and admitted forensic State patients at Weskoppies Psychiatric Hospital. Data were captured in an electronic recording sheet. The association between factors and the outcome measure (discharged vs. admitted) was determined using chi-squared tests and Fischer’s exact tests.ResultsDischarged State patients were associated with being a primary caregiver (p = 0.031) having good insight into illness (p = 0.025) or offence (p = 0.005) and having had multiple successful leaves of absences. A lack of substance abuse during admission (p = 0.027), an absence of a diagnosis of substance use disorder (p = 0.013) and the absence of verbal and physical aggression (p = 0.002 and p = 0.016) were associated with being discharged. Prolonged total length of stay (9–12 years, p = 0.031) and prolonged length of stay in open wards (6–9 years, p = 0.000) were associated with being discharged. A history of previous offences (p = 0.022), a diagnosis of substance use disorder (p = 0.023), recent substance abuse (p = 0.018) and a history of physical aggression since admission (p = 0.017) were associated with continued admission.ConclusionDischarge of State patients is associated with an absence of substance abuse, lack of aggression, multiple successful leave of absences and length of stay in hospital.

Outnumbered: a new dominant ant species with genetically diverse supercolonies in Ethiopia

A Lepisiota (Hymenoptera: Formicidae: Formicinae) species in Ethiopia has been observed forming supercolonies spanning up to 38 km. L. canescens occurs at very high densities where there is sufficient moisture or herbaceous cover and dominates the local ant community, traits reminiscent of an invasive species. The supercolonies are genetically diverse, however, indicating they have not gone through the population bottleneck usually characteristic of species invasions. We conclude that the species is native to this region, though expanding its range locally into areas of human disturbance, where it is exploding in numbers. The lack of aggression across a genetically diverse population suggests that mitochondrial genetic variation is decoupled from variation relating to colony recognition cues like cuticular hydrocarbons. All in all, L. canescens could have the makings of an invasive species at an international scale and may represent a novel system to study the evolution and spread of supercolonies in ants.

Lack of aggression and apparent altruism towards intruders in a primitive termite.

In eusocial insects, the ability to discriminate nest-mates from non-nest-mates is widespread and ensures that altruistic actions are directed towards kin and agonistic actions are directed towards non-relatives. Most tests of nest-mate recognition have focused on hymenopterans, and suggest that cooperation typically evolves in tandem with strong antagonism towards non-nest-mates. Here, we present evidence from a phylogenetically and behaviourally basal termite species that workers discriminate members of foreign colonies. However, contrary to our expectations, foreign intruders were the recipients of more rather than less cooperative behaviour and were not subjected to elevated aggression. We suggest that relationships between groups may be much more peaceable in basal termites compared with eusocial hymenoptera, owing to energetic and temporal constraints on colony growth, and the reduced incentive that totipotent workers (who may inherit breeding status) have to contribute to self-sacrificial intergroup conflict.

The relationship between different types of genetically defined aggressive behavior

Aggressive behavior is not a unitary trait, and different stimuli/situations elicit different kinds of aggressive behavior. According to numerous data the genotype plays a significant role in the expression of aggressive behavior. However, it remains unclear how genetic predisposition to one kind of aggression is linked with other kinds of aggressive behavior, especially pathological aggression (infanticide). Here, we report on our investigation of the expression of defensive, offensive, predatory and asocial aggression in wild rats selectively bred for 85 generations for either a high level or a lack of aggression towards humans. We found that those rats genetically predisposed to a high level of defensive aggression showed decreased social behavior and increased pathological aggressive behavior towards juvenile males. The highly aggressive rates showed a reduced latency time of attack and an increased latency time of the first social contact. Rats genetically predisposed to defensive aggression demonstrated increased predatory aggression—latency time of muricide was shorter in highly aggressive than in tame animals. At the same time, both lines of rats did not differ significantly in intermale aggression. We conclude that the data indicate a close relation between defensive, predatory and pathological aggressive behavior that allows us to suggest that similar genetic mechanisms underlie these types of aggressive behavior.

Intraspecific and interspecific aggression among Flame, Scarlet and Dusky Robins

Flame Petroica phoenicea and Scarlet Robins Petroica boodang are interspecifically territorial wherever they meet. However, aggressive interactions between Dusky Robins Melanodryas vittata and these two species are rare where they co-occur. Interspecific aggression among co-existing species may be due to competition for resources. In this study at Cloudy Bay, South Bruny Island, Tasmania, in August 2004–February 2005, I examined intraspecific and interspecific territoriality in Flame, Scarlet and Dusky Robins by observing displays of aggression within and between the three species. I also used song-playback experiments to test whether the robins could discriminate between conspecific and congeneric species. Flame and Scarlet Robins responded differentially to playback of each other’s song, but did not respond to Dusky Robin calls. Aggression between Flame and Scarlet Robins may be because of competition for horizontal space or resources. Conversely, the lack of aggression between Dusky Robins and these two species may be because of their ability to exploit different resources even when they are in the same area.

Thermal limit of Euastacus sulcatus (Decapoda: Parastacidae), a freshwater crayfish from the highlands of central eastern Australia

Increased temperature as a potentially threatening process, and the need to investigate the thermal tolerance of the ‘highland-rainforest’ Euastacus were first identified 20 years ago; however, the thermal repertoire of Euastacus has still not been explored. Euastacus is the largest of Australia’s 10 freshwater crayfish genera with 52 species, and includes many of the largest, slowest-growing and longest-lived species (some >35 years) in the World. Several species have distributions consistent with being ‘climate refugees’, namely, being closely associated with cool, damp conditions and restricted to isolated mountain-top refuges. The present study investigated the critical thermal limit of a well known abundant species, Euastacus sulcatus, from central eastern Australia. Thermal limit was assessed using chronic, ongoing exposure to steadily increasing temperature, with the breakdown of physiological function tested by righting response. Distress was clearly evident in the crayfish at ~23°C (e.g. sluggish, lack of aggression), and the test criterion was met at ~27°C, with animals effectively incapacitated and unable to right themselves. Field water temperatures rarely exceed 21°C; however, any increases in environmental temperature may expose this species to temperatures where physiological stress may become problematic.

Precision Rescue Behavior in North American Ants

Altruistic behavior, in which one individual provides aid to another at some cost to itself, is well documented. However, some species engage in a form of altruism, called rescue, that places the altruist in immediate danger. Here we investigate one such example, namely rescuing victims captured by predators. In a field experiment with two North American ant species, Tetramorium sp. E and Prenolepis imparis, individuals were held in artificial snares simulating capture. T. sp. E, but not P. imparis, exhibited digging, pulling, and snare biting, the latter precisely targeted to the object binding the victim. These results are the first to document precision rescue in a North American ant species; moreover, unlike rescue in other ants, T. sp. E rescues conspecifics from different colonies, mirroring their atypical social behavior, namely the lack of aggression between non-nestmate (heterocolonial) conspecifics. In a second, observational study designed to demonstrate rescue from an actual predator, T. sp. E victims were dropped into an antlion's pit and the behavior of a single rescuer was observed. Results showed that T. sp. E not only attempted to release the victim, but also risked attacking the predator, suggesting that precision rescue may play an important role in this species' antipredator behavior.

Natural history and behaviour ofDunatothrips aneurae Mound (Thysanoptera: Phlaeothripidae), a phyllode-gluing thrips with facultative pleometrosis

Thrips of the genus Dunatothrips (Thysanoptera: Phlaeothripidae) construct domiciles by tying phyllodes of Australian Acacia trees together with silk-like glue. Females often co-found domiciles (pleometrosis), an apparently cooperative behaviour that potentially provides insights into social evolution. However, little is known about their basic natural history, limiting the scope for testable predictions. Here, we address this crucial prerequisite step by investigating some key outstanding questions in the most common species, D. aneurae, on its host, Acacia aneura. We detail distribution in space and time, mating, dispersal, domicile building and defence. Dunatothrips aneurae was distributed in loosely reproductively synchronized patches, and tended to prefer east-facing, terminal phyllodes on thin-phyllode A. aneura varieties. Mature domiciles contained middens, concentrated areas of waste, suggesting active maintenance of domiciles and the potential for the division of labour. We observed inbreeding and outbreeding. Dunatothrips aneurae males engaged in short, truncated matings with sisters before dispersing locally, mating with females in nearby immature domiciles; longer distance dispersal, although it must happen, is still undocumented. Males and females mated multiply. Lone females required male presence to initiate domiciles, constructed them without male help and lost wings on nesting by abscission. Silk production occurred well before egg laying. Aggression or defence appeared to be entirely absent. Taken together, these observations suggest that research into co-founding behaviour should focus on: (1) local crowding; (2) lack of aggression; and (3) potential division of labour with respect to egg production, silk production and domicile maintenance. These results should provide a springboard for questions on the potential evolution of cooperation in this species. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109, 802-816.

Socialization of a Single Hand-Reared Tiger Cub

Given the drawbacks of hand-rearing nonhuman animals in captivity, the practice is generally avoided, but it is sometimes necessary. A few scientific publications are available to guide managers toward best practices in hand-rearing, but the majority of articles focus on hand-rearing captive primates. Less is known about hand-rearing carnivores, but early socialization appears to be critical for adult social behavior. This article documents the successful hand-rearing and reintroduction of a single female Sumatran tiger cub at Zoo Atlanta. Reintroduction included a systematic procedure that used scent trials and introduction sessions through a barrier to gauge interest and determine whether or not aggression was a problem. Based on signs of interest, reduced stress-related behaviors, and a lack of aggression, animal managers decided to proceed with reintroduction. During the introductions, the animals were not aggressive and did occasionally interact, although typical mother–infant interactions were rare. The cub has since bred naturally and successfully delivered and reared two litters of cubs. These data suggest limited exposure to an adult tiger may be adequate socialization for normal reproduction even if it is provided relatively late in the cub's development.

Host Plant Use by Competing Acacia-Ants: Mutualists Monopolize While Parasites Share Hosts

Protective ant-plant mutualisms that are exploited by non-defending parasitic ants represent prominent model systems for ecology and evolutionary biology. The mutualist Pseudomyrmex ferrugineus is an obligate plant-ant and fully depends on acacias for nesting space and food. The parasite Pseudomyrmex gracilis facultatively nests on acacias and uses host-derived food rewards but also external food sources. Integrative analyses of genetic microsatellite data, cuticular hydrocarbons and behavioral assays showed that an individual acacia might be inhabited by the workers of several P. gracilis queens, whereas one P. ferrugineus colony monopolizes one or more host trees. Despite these differences in social organization, neither of the species exhibited aggressive behavior among conspecific workers sharing a tree regardless of their relatedness. This lack of aggression corresponds to the high similarity of cuticular hydrocarbon profiles among ants living on the same tree. Host sharing by unrelated colonies, or the presence of several queens in a single colony are discussed as strategies by which parasite colonies could achieve the observed social organization. We argue that in ecological terms, the non-aggressive behavior of non-sibling P. gracilis workers — regardless of the route to achieve this social structure — enables this species to efficiently occupy and exploit a host plant. By contrast, single large and long-lived colonies of the mutualist P. ferrugineus monopolize individual host plants and defend them aggressively against invaders from other trees. Our findings highlight the necessity for using several methods in combination to fully understand how differing life history strategies affect social organization in ants.

Genetic Relatedness and Chemical Profiles in an Unusually Peaceful Eusocial Bee

Colonies of the stingless bee Tetragonilla collina frequently occur in unusually high densities and in direct neighborhood (nest aggregations), in rainforests of Southeast Asia. To investigate whether close relatedness and/or similar chemical profiles facilitate the co-occurrence of multiple T. collina colonies, we investigated aggressive behavior, genetic relatedness and cuticular hydrocarbon (CHC) profiles within and between colonies and nest aggregations. Although 17 out of 19 colonies within aggregations were largely unrelated, intraspecific aggression between different colonies was basically absent both within and among aggregations. This lack of aggression should favor social parasitism and hence the occurrence of unrelated individuals within a colony. However, low within-colony relatedness was found in only five out of 19 colonies where it may be explained by queen turnover or the occurrence of foreign workers. CHC profiles of colonies within and among aggregations were statistically different. However, many workers could chemically not be assigned to their maternal colony, indicating considerable overlap among colonies in odor profiles of workers. Moreover, odor profiles tended to be more similar within than among aggregations, although most colonies were unrelated. Thus, CHC profiles were a poor indicator of relatedness in T. collina. The lack of correlation between relatedness and chemical similarity in T. collina may be explained by the incorporation of resin-derived terpenes in their CHC profiles. The composition of these terpenes was highly similar among colonies, particularly within aggregations, hence potentially decreasing chemical distinctiveness and increasing behavioral tolerance.

Socially peaceful: foragers of the eusocial bee Lasioglossum malachurum are not aggressive against non-nestmates in circle-tube arenas

Due to the universally found nestmate recognition in eusocial insects, it is predictable that non-nestmates interact aggressively. In sweat bees (Hymenoptera: Halictidae), this trend was largely shown for queen–queen interactions, but data on worker–worker interactions are still scarce and somehow controversial. We studied behavioural interactions between foragers of the eusocial and ground-nesting bee Lasioglossum malachurum within circle-tubes. Independently of colony membership, bees exhibited high frequencies of cooperative behaviours, together with lack of aggression and moderate avoidance of social interactions. The cooperative mutual passing was the most frequently recorded behaviour. Size difference between the opponents had no effects on cooperation or avoidance. In a heterospecific experiment, bee foragers were observed to react more aggressively and to pass very rarely towards cuckoo bees, suggesting that our results were not biased by the circle-tube methodology. Our results and comparisons with other bee species suggest that studying worker interactions may be not enough to predict the social organisation in bees. Whatever the evolutionary meaning of this generalised tolerance towards conspecifics, the present findings are somehow in agreement with recent studies showing that L. malachurum colonies may have imperfect nestmate recognition and often include a mixture of related and unrelated workers.

Cleared for Takeoff: Air Passenger Efficiency Training in the Post-9/11 Era

Cleared for Takeoff: Air Passenger Efficiency Training in the Post-9/11 Era Rachel Hall (bio) The Transportation Security Administration (TSA) and other security agencies internationally began requiring passengers to place their regulation-size liquids, gels, and aerosols in a clear plastic bag in the fall of 2006. The policy was instituted in response to a thwarted attempt to blow up a British airplane using liquid explosives. Initially, the TSA banned all liquids, gels, and aerosols. The agency subsequently loosened its restrictions. It would allow each passenger to carry three-ounce or smaller containers of liquids or gels, sealed in a one quart-size clear plastic, zip-top bag, to be placed in a gray security bin for inspection by TSA officers stationed at security checkpoints. The zip-top bag rule is merely one example of a broader pattern by which the TSA defines safety in visual terms as the absence of threat. Passengers and their belongings are made safe or “cleared” for takeoff once they have been seen through by security officials. “Safe” is the aesthetic effect of transparency: produced in passengers and their belongings via processes of seeing through the exterior to the interior, and a regulatory achievement: the governmental status of having been “cleared” for takeoff is bestowed upon passengers and their belongings once they have passed visual inspection. But to understand airport security screening as a unidirectional process of mediation by the security state is to miss the extent to which passengers are expected to play an active role in rendering their bodies and belongings “safe” for flight (i.e., transparent). In addition to being an aesthetic effect and regulatory achievement, “safe” also refers to the passenger’s efficient performance of submission to security screening: her live demonstration of a state of readiness-for-inspection. Just as the passenger [End Page 315] demonstrates the literal absence of the threat of explosives by showing her regulation-size bag of liquids and gels to security officers, she must also demonstrate the absence of the threat of disobedience by showing security officials how well she takes direction. The “safe” passenger performs metaphoric transparency by showing TSA officers that she is adept at the art of self-assessment (i.e., she knows whether she belongs in the slow or fast lane) and via her affective performance as she moves through the security checkpoint. The passenger performs nothing-to-hide by demonstrating her lack of aggression, frustration, or hostility as she waits in line to submit to federal security regulations. To be fair, the TSA places a premium on efficient passenger submission to screening at the checkpoint because the agency is under tremendous public pressure to prevent another terrorist attack without unnecessarily delaying the flow of people, goods, and materials vital to global capitalism. The global citizen’s mobility is productive, but the global suspect’s mobility is threatening. Spokespersons for the TSA regularly state that the agency considers its two most important jobs to be security and customer service. This was not always or immediately the case: “When we started we had more of a military thing,” said Lori Potoczek, a screening supervisor at O’Hare International Airport in Chicago. “Now we need to be more businesslike” (Bailey and Peters 2005). And, she might have added, passengers will also need to retool themselves in order to meet the TSA’s efficiency standards. Taking its cue from American consumer and media cultures, the TSA has adopted the ruse of interactivity in order to promote reflexive governance at the checkpoint, whereby passengers take on more of the responsibility for making the checkpoint function in a smooth and efficient manner.1 Passenger performances of efficient submission operate on multiple registers of transparency. On a primary level, the passenger’s literal transparency promotes efficient inspection as in the case of the zip-top bags used to display the passenger’s regulation-size toiletries to TSA officers. On a secondary level, her live performance of efficient submission—knowing the zip-top bag rule and arriving at the checkpoint prepared to follow it—signals the passenger’s metaphoric transparency. In other words, the passenger’s safety status with the TSA is performance based. Transportation security pedagogy...

Genetic and behavioural evidence for a city‐wide supercolony of the invasive Argentine ant Linepithema humile (Mayr) (Hymenoptera: Formicidae) in southeastern Australia

AbstractThe success of invasive ants is frequently attributed to genetic and behavioural shifts in colony structure during or after introduction. The Argentine ant (Linepithema humile), a global invader, differs in colony genetic structure and behaviour between native populations in South America and introduced populations in Europe, Japan, New Zealand and North America. However, little is known about its colony structure in Australia. We investigated the genetic structure and behaviour of L. humile across Melbourne, Victoria by quantifying variation at four microsatellite loci and assaying intraspecific aggression at neighbourhood (30–200 m), fine (1–3.3 km) and regional (5–82 km) spatial scales. Hierarchical analyses across these scales revealed that most genetic variation occurred among workers within nests (∼98%). However, although low genetic differentiation occurred among workers between nests at the fine and regional scales (∼2%), negligible differentiation was detected among workers from neighbouring nests. Spatial genetic autocorrelation analysis confirmed that neighbouring nests were genetically more similar to each other. Lack of aggression within and across these scales supported the view that L. humile is unicolonial and forms a large supercolony across Melbourne. Comparisons of genetic structure of L. humile among single nests sampled from Adelaide, Brisbane, Hobart and Perth with Melbourne showed no greater levels of genetic differentiation or dissimilar spatial structure, suggesting an Australia‐wide supercolony.