Hereditary nature of death-feigning frequency in a parasitoid wasp Heterospilus prosopidis using sib analysis.

Death feigning, a state of immobility observed in many animals in response to external stimuli, is an anti-predator behaviour. Although previous studies showed that death-feigning behaviours are quantitative genetic traits, the knowledge of the heritable basis of death-feigning behaviour is lacking. To investigate the heritable basis of death-feigning behaviour, we used 3 laboratory strains of a braconid parasitoid wasp, Heterospilus prosopidis. The heritable basis using half-sib analysis, and the effects of different geographical backgrounds, rearing conditions in the laboratory, and host age were evaluated. The results of the half-sib analysis showed that the frequency of death feigning varied among sires, suggesting a certain extent of additive genetic variance. Also, the frequency of death feigning varied between geographical backgrounds and among strains. Death-feigning frequency was not affected by the age of the host. Our findings highlight the importance of genetic factors underlying the basis of the death-feigning behaviour and provide support for the genetic alterations of traits from the perspective of evolution in various animal species.

Tonic immobility (freezing) during sexual and physical assaults produces stronger memory effects than other characteristics of the assaults.

Tonic immobility (TI) is a phylogenetically conserved, passive, obligatory defense mechanism commonly engaged during sexual and physical assaults. During TI, people become immobile while remaining conscious and later reexperience intrusive memories of both their assault and of its accompanying immobility. Here we show that this well-studied biological process has powerful effects on memory and other processes. Participants had experienced either a serious sexual (n = 234) or physical (n = 137) assault. For both the assault and its accompanying immobility, the standard measure of the peritraumatic severity of TI correlated between .40 and .65 with post-assault effects on memory, including memory of the assault and memory of the immobility, the two memory-based self-concept measures of self-blame and event centrality, and post-assault anxiety and depression. The correlations with TI were much higher than other peritraumatic characteristics commonly used to predict and describe posttraumatic effects in assaults and other traumas. The results suggest that TI should be considered for a broader, more biologically based and ecologically valid understanding of the effects of trauma on memory and memory-based reactions.

Using shame to extend Martin Conway's self-memory system.

We extend Conway's self-memory system by adding theory and data from shame, an emotion that disrupts the internalised ideals of society needed for a positive self-concept. The event that caused 273 undergraduates their greatest amount of shame was analyzed; 66% were not very negative except for producing shame. Ratings of post-event effects, including two measure of self (self-perceived weakness, and centrality to identity) and four clinical symptoms (intrusions, avoidance, anxiety, and depression), were attributed separately to the remembered event, behaviour during the event, and shame from the event. The effects of shame were generally as large as the those of the event and larger than those of the behaviour, demonstrating the importance of shame's effects. The Tonic Immobility Scale (TIS), which measures tonic immobility (i.e., freezing), was obtained for the event that produced the most tonic immobility but that was not the event that caused the most shame. The post-event symptoms measured on the event that caused the most shame and the TIS correlated highly, suggesting that shame and tonic immobility may belong to a cluster of phylogenetically conserved submissive defensive mechanisms that could account for effects currently attributed to goals in self-memory systems.

Why fake death? Environmental and genetic control of tonic immobility in larval lacewings (Neuroptera: Chrysopidae).

Tonic immobility is a passive antipredator strategy employed late in the predation sequence that may decrease individual mortality in prey animals. Here, we investigate how energetic state and genetic predisposition influence antipredator decision-making in green lacewing larvae, Chrysoperla plorabunda (Fitch), using simulated predatory encounters. We demonstrate that tonic immobility is a plastic response influenced by energetic resource limitation. Larvae exposed to 1 or 2 days of food deprivation initiate tonic immobility more often and with less physical provocation than individuals fed ad libitum. Recently molted individuals exposed to food deprivation, the individuals most energetically challenged, engage in tonic immobility at a higher rate than any other group. We also find that variation in antipredator strategy between individuals is partly the result of within-population genetic variation. We estimate the propensity to enter tonic immobility to have a broad-sense heritability of 0.502. Taken together our results suggest that larval lacewings under energetic stress are more likely to engage in tonic immobility. Yet, energetic state does not explain all within-population variation, as individuals can have a genetic predisposition for tonic immobility.

Differences in innate fear behaviour in native Japanese chickens.

1. Comprehensive knowledge of innate fear in chickens has important implications for understanding the adaptation of native Japanese chickens in modern production and behavioural changes caused by modern breeding goals. Innate fear behaviour seen in chicks from six native Japanese chicken breeds;, Ingie (IG), Nagoya (NAG), Oh-Shamo (OSM), Tosa-Jidori (TJI), Tosa-Kukin (TKU) and Ukokkei (UK), were compared with those in two lines of White Leghorn (WL-G and WL-T) in tonic immobility (TI) and open field (OF) tests.2. TI and OF tests were conducted for 267 chicks at 0-1 days of age in the eight breeds. Raw data for four TI traits and 13 OF traits were corrected for environmental factors. Breed differences were analysed by the Kruskal-Wallis test followed by the Steel Dwass post hoc test. Principal component (PC) analyses were conducted.3. The results showed that OSM was the least sensitive to fear in both the TI and OF tests. The WL-G birds showed higher sensitivity to TI fear but lower sensitivity to OF fear. The PC analysis of OF traits classified the tested breeds into three groups: least (OSM and WL-G), moderate (IG, WL-T, NAG, TJI and TKU) and most sensitive (UK).

Effect of different pasture species on welfare and behavior of slow-growing broiler chickens in free-range production system.

This study investigated the effect of various pasture species on the welfare and behavior of slow-growing broiler chickens in the free-range production system. After 21 days completely indoors, the birds were permitted access to outdoor pens cultivated with one of the following pasture treatments: Medicago sativa (A), Trifolium repens (WC), Lolium perenne (PR), and a mixture (Mix, A + WC + PR). The range availability was restricted between 08:30 and 16:30 daily. It was found that pasture type had a significant effect on the fluctuating asymmetry of the face and radius length (P < 0.01). Duration of tonic immobility and blood parameters did not differ among the pasture species and between sexes at 11 weeks of broiler age (P > 0.05). Pasture treatment had no significant effect on broiler behaviors (P > 0.05). However, the age of broilers had a significant effect on pecking, dustbathing, and scratching (P < 0.01). Pecking behavior was affected by the time of the day; morning and afternoon (P < 0.01). Location had a significant effect on pecking and stretching behaviors (P < 0.01). In the study, dustbathing behavior was significantly affected by the interaction between location and age (P < 0.01), age and time of the day (P < 0.01), and location, age, and time of the day (P < 0.05). Scratching behavior was significantly affected by the interaction between location and time of the day (P < 0.05) and location, age and time of the day (P < 0.01). Stretching behavior was significantly affected by the interaction between location and age (P < 0.05) and location, age and time of the day (P < 0.05). It was concluded that access to the studied pasture species does not affect the evaluated welfare traits and observed behaviors. Therefore, it is suggested that other pasture species should be investigated to identify their effect on slow-growing strains in the free-range production system.

Are memories of sexual trauma fragmented?

Alarmingly high rates of sexual assault on campus have motivated American colleges and universities to take steps to address this serious problem. Yet university administrators have often felt ill-equipped to assess allegations of sexual assault. Unsurprisingly, they have sought the expertise of psychologists who can educate administrative staff about the complexities of traumatic memory. Dr. Rebecca Campbell is among the most influential figures teaching university administrators about sexual trauma and memory. The purpose of this article is to review research pertinent to her views on fragmentation of traumatic memories, and the possible roles of tonic immobility and alcohol consumption on how survivors of sexual assault recall their experience.

Lateralized motor behaviour in the righting responses of the cane toad (Rhinella marina).

This paper reports a series of tests for fore- and hind-limb preferences used by cane toads, Rhinella marina, to assist returning to the righted position after being overturned. We confirm the strong and significant right-handedness reported in this species, which under certain conditions exceeded 90% right-hand preference at the group level. Toads were tested under a variety of conditions including horizontal and inclined surfaces, with and without the opportunity for the forelimbs to grasp a support, in order to assess the effects of different vestibular and proprioceptive input on the strength and direction of fore- and hind-limb preferences. A range of behavioural strategies indicated learning effects; however, the strength or direction of limb preferences did not increase significantly with experience, even in toads retested multiple times. Comparisons with the mammalian condition for limb preferences are discussed with relevance to practice effects and established limb preferences, and to effects associated with arousal or stress. In contrast to the expectation that handedness in toads represents intentional or voluntary preferences, the presence of lateralized central pattern generators in the toads is postulated to explain the different forms of lateralization revealed by our tests.

The effect of monochromatic, combined, and mixed light-emitting diode light regimes on growth traits, fear responses, and slaughter-carcass characteristics in broiler chickens.

This study aims to determine the effects of blue and green monochromatic, blue-green combination, and blue-green mixed led lighting systems on growth, fear, and carcass characteristics of broilers reared in an extensive indoor system. Experimental groups were formed as follows; 1-conventional (incandescent), 2-blue, 3-green, 4-blue-green combined (blue for the first 10 days, then green), 5-green-blue combined (green for the first 10 days, then blue), and 6-blue-green intermittent (alternating every 5 min) monochromatic lightings. It was detected that the average values of the body weight of chickens at 42 and 56 days of age in the green-blue group were higher than those of the other treatment groups (both P < 0.05). It was determined that the broilers in the green and green-blue groups had higher means of the ß0 parameter of Gompertz model. The tonic immobility, emergence test, home cage avoidance test, a looming human test, and box plus experimenter test were applied to determine the fear responses. It was determined that the worst results for fear responses of broilers were in the intermittent lighting group and green-blue combined group. As a result, it was determined that the application of green monochromatic lighting in the first 10 days of the fattening period and blue monochromatic lighting in the following period positively affected growth and slaughter-carcass characteristics. However, it was found that broilers reared under green-blue combined lighting had high fear levels.

Cannabidiol has a unique effect on global brain activity: a pharmacological, functional MRI study in awake mice.

BACKGROUND: The phytocannabinoid cannabidiol (CBD) exhibits anxiolytic activity and has been promoted as a potential treatment for post-traumatic stress disorders. How does CBD interact with the brain to alter behavior? We hypothesized that CBD would produce a dose-dependent reduction in brain activity and functional coupling in neural circuitry associated with fear and defense. METHODS: During the scanning session awake mice were given vehicle or CBD (3, 10, or 30 mg/kg I.P.) and imaged for 10 min post treatment. Mice were also treated with the 10 mg/kg dose of CBD and imaged 1 h later for resting state BOLD functional connectivity (rsFC). Imaging data were registered to a 3D MRI mouse atlas providing site-specific information on 138 different brain areas. Blood samples were collected for CBD measurements. RESULTS: CBD produced a dose-dependent polarization of activation along the rostral-caudal axis of the brain. The olfactory bulb and prefrontal cortex showed an increase in positive BOLD whereas the brainstem and cerebellum showed a decrease in BOLD signal. This negative BOLD affected many areas connected to the ascending reticular activating system (ARAS). The ARAS was decoupled to much of the brain but was hyperconnected to the olfactory system and prefrontal cortex. CONCLUSION: The CBD-induced decrease in ARAS activity is consistent with an emerging literature suggesting that CBD reduces autonomic arousal under conditions of emotional and physical stress.

Post-contact immobility and half-lives that save lives.

A wide variety of animals become completely immobile after initial contact with a potential predator. This behaviour is considered to be a last-ditch escape strategy. Here, we test the hypothesis that such immobility should have an extremely unpredictable duration. We find that it spans more than three orders of magnitude in antlion larvae. We also analyse the second period of immobility that follows the first bout of immobility, and consider the distributions of both first and second immobility periods within the context of the intermittence that characterizes the movement of most organisms. Both immobility durations were fitted best by exponential distributions. Therefore, both were characterized by high variability and hence, unpredictability. The immobility half-life, its mean duration and standard deviation were greater for the first than the second immobility. Furthermore, individual consistency was weak or absent in repeated measures of the first immobility and between the first and second immobilities. Our quantitative approach can be replicated across taxa and would help link an understanding of immobility after an initial predator contact in both vertebrates and invertebrates. To facilitate this, we contend that the terminology should be simplified, and we advocate the use of the term post-contact immobility (PCI).

Death feigning as an adaptive anti-predator behaviour: Further evidence for its evolution from artificial selection and natural populations.

Death feigning is considered to be an adaptive antipredator behaviour. Previous studies on Tribolium castaneum have shown that prey which death feign have a fitness advantage over those that do not when using a jumping spider as the predator. Whether these effects are repeatable across species or whether they can be seen in nature is, however, unknown. Therefore, the present study involved two experiments: (a) divergent artificial selection for the duration of death feigning using a related species T. freemani as prey and a predatory bug as predator, demonstrating that previous results are repeatable across both prey and predator species, and (b) comparison of the death-feigning duration of T. castaneum populations collected from field sites with and without predatory bugs. In the first experiment, T. freemani adults from established selection regimes with longer durations of death feigning had higher survival rates and longer latency to being preyed on when they were placed with predatory bugs than the adults from regimes selected for shorter durations of death feigning. As a result, the adaptive significance of death-feigning behaviour was demonstrated in another prey-predator system. In the second experiment, wild T. castaneum beetles from populations with predators feigned death longer than wild beetles from predator-free populations. Combining the results from these two experiments with those from previous studies provided strong evidence that predators drive the evolution of longer death feigning.

Genetic Architecture of Innate Fear Behavior in Chickens.

The genetic architecture of innate fear behavior in chickens is poorly understood. Here, we performed quantitative trait loci (QTL) analysis of innate responses to tonic immobility (TI) and open field (OF) fears in 242 newly hatched chicks of an F2 population between the native Japanese Nagoya breed and the White Leghorn breed using 881 single nucleotide polymorphism markers obtained by restriction site-associated DNA sequencing. At genome-wide 5% significance levels, four QTL for TI traits were revealed on chromosomes 1-3 and 24. Two of these loci had sex-specific effects on the traits. For OF traits, three QTL were revealed on chromosomes 2, 4 and 7. The TI and OF QTL identified showed no overlaps in genomic regions and different modes of inheritance. The three TI QTL and one OF QTL exerted antagonistic effects on the traits. The results demonstrated that context-dependent QTL underlie the variations in innate TI and OF behaviors.

Anti-predator behaviour depends on male weapon size.

Tonic immobility and escape are adaptive anti-predator tactics used by many animals. Escape requires movement, whereas tonic immobility does not. If anti-predator tactics relate to weapon size, males with larger weapons may adopt tonic immobility, whereas males with smaller weapons may adopt escape. However, no study has investigated the relationship between weapon size and anti-predator tactics. In this study, we investigated the relationship between male weapon size and tonic immobility in the beetle Gnathocerus cornutus. The results showed that tonic immobility was more frequent in males with larger weapons. Although most studies of tonic immobility in beetles have focused on the duration, rather than the frequency, tonic immobility duration was not affected by weapon size in G. cornutus. Therefore, this study is the first, to our knowledge, to suggest that the male weapon trait affects anti-predator tactics.

The role of tonic immobility and control in the development of intrusive memories after experimental trauma.

Tonic immobility (TI; state of motor inhibition during threat) has been implicated in the onset of intrusive trauma memories, while controllability was associated with reduced anxiety. The present study investigated the interaction between TI and control in the development of intrusive memories of an analogue trauma. Sixty-four participants watched negative pictures while being allowed to close their eyes (InControl) or not (NoControl). They completed measures for spontaneous TI afterwards and recorded intrusive memories of the pictures in a diary in the subsequent week. Bayesian analyses were used to test informative hypotheses. Spontaneous TI during picture viewing was positively associated with increased intrusion frequency. Intrusion frequency did not differ for InControl versus NoControl. Moderation (control x TI) and non-moderation (main effect of TI only) were both adequate models, with no preference. Our results confirm the importance of TI in PTSD development. Implications of the findings regarding control merit more research.

Strange-face illusions during eye-to-eye gazing in dyads: specific effects on derealization, depersonalization and dissociative identity.

Experimentally induced strange-face illusions can be perceived when two individuals look at each other in the eyes under low illumination for about 10 minutes. This task of subject-other eye-to-eye gazing produces the following perceptions by the subject: (i) mild to huge deformations and color/shape changes of face and facial features; (ii) lifeless, unmoving faces and immaterial presences akin to out-of-body experiences; (iii) pseudo-hallucinations, enlightened 'idealized' faces and personalities - rather than the other's actual face. Dissociative phenomena seem to be involved, whereas the effects of non-pathological dissociation on strange-face illusions have not yet been directly investigated. In the present study, dissociative perceptions and strange-face illusions were measured through self-report questionnaires on a large sample (N = 90) of healthy young individuals. Results of correlation and factor analyses suggest that strange-face illusions can involve, respectively: (i) strange-face illusions correlated to derealization; (ii) strange-face illusions correlated to depersonalization; and (iii) strange-face illusions of identity, which are supposedly correlated to identity dissociation. The findings support the separation between detachment and compartmentalization in dissociative processes. Effects of gender show that strange-face illusions are more frequent in men with respect to women if dyads are composed of individuals of different-gender. Furthermore, drawings of strange-faces, which were perceived by portrait artists in place the others' faces, allowed a direct illustration of examples of dissociative identities. Findings are discussed in relation to the three-level model of self-referential processing.

Decoupling of Behavioral Trait Correlation Across Life Stages in Two Holometabolous Insects.

Many animal behaviors have a genetic base, and behavioral traits often correlate with one another. In this study, we tested for a behavioral correlation between tonic immobility and walking distance in the larval and adult stages independently of two holometabolous insects. We confirmed a negative correlation of traits between strains in adults of both the species; however, we did not find it in larvae of either species. This suggests that the negative correlation between tonic immobility and walking is decoupled across life stages from larva to adult. In contrast, previous studies have reported that phenotypic correlations between behavioral traits are maintained from larvae to adults in hemimetabolous insects. In addition, our present results differ from previous results with holometabolous insects. Therefore, our results suggest that metamorphosis can change trade-offs between behavioral traits.

Effect of melatonin injection into the periaqueductal gray on antinociception and tonic immobility in male rats.

Melatonin (MLT) is a neurohormone with significant involvement in several biological functions, of which antinociception and tonic immobility (TI) may be the key neurobehavioral components to survive in adverse conditions such as a predator attack. TI-induced antinociception can be elicited, facilitated, or increased through opioid and γ-aminobutyric acid (GABA) among other chemical mediators at several levels of the central nervous system, mainly in the periaqueductal gray (PAG). The aim of this study was to assess the effect of the microinjection of MLT into the main PAG regions that are related to different integrated defensive responses, namely dorsal (D) and ventrolateral (VL), on both antinociception through the tail-flick (TF) test and TI duration as single behavioral response and on combined behavioral responses (TF/TI). We found that the microinjection of MLT into the main PAG areas produced antinociception but did not affect the TI duration. The microinjection of MLT into the D-PAG decreased TF latency during TI in the combined trial (TF/TI), which implies that TI-induced antinociception was blocked. The microinjection of MLT into the VL-PAG maintained the antinociceptive capability of the TI without addition or increase in the antinociceptive effects, implying a permissive effect by MLT on the TI-induced antinociception. MLT administration into the D-PAG decreased the TI duration on the TF/TI, whereas MLT administration into the VL-PAG had the opposite effect of significantly increasing TI duration with the TF/TI trial.

Tonic immobility during sexual assault - a common reaction predicting post-traumatic stress disorder and severe depression.

INTRODUCTION: Active resistance is considered to be the 'normal' reaction during rape. However, studies have indicated that similar to animals, humans exposed to extreme threat may react with a state of involuntary, temporary motor inhibition known as tonic immobility. The aim of the present study was to assess the occurrence of tonic immobility during rape and subsequent post-traumatic stress disorder and severe depression. MATERIAL AND METHODS: Tonic immobility at the time of the assault was assessed using the Tonic Immobility Scale in 298 women who had visited the Emergency clinic for raped women within 1 month of a sexual assault. Information about the assault and the victim characteristics were taken from the structured clinical data files. After 6 months, 189 women were assessed regarding the development of post-traumatic stress disorder and depression. RESULTS: Of the 298 women, 70% reported significant tonic immobility and 48% reported extreme tonic immobility during the assault. Tonic immobility was associated with the development of post-traumatic stress disorder (OR 2.75; 95% CI 1.50-5.03, p = 0.001) and severe depression (OR 3.42; 95% CI 1.51-7.72, p = 0.003) at 6 months. Further, previous trauma history (OR 2.36; 95% CI 1.48-3.77, p < 0.001) and psychiatric treatment history (OR 2.00; 95% CI 1.26-3.19, p = 0.003) were associated with the tonic immobility response. CONCLUSIONS: Tonic immobility during rape is a common reaction associated with subsequent post-traumatic stress disorder and severe depression. Knowledge of this reaction in sexual assault victims is important in legal matters and for healthcare follow up.

Exogenous administration of chronic corticosterone affects hepatic cholesterol metabolism in broiler chickens showing long or short tonic immobility.

Tonic immobility (TI) is an innate characteristic of animals related to fear or stress response. Animals can be classified into long TI (LTI) and short TI (STI) phenotypes based on TI test duration. In this study, effect of TI phenotype, chronic corticosterone administration (CORT), and their interaction on cholesterol metabolism in liver was evaluated in broilers. LTI broilers showed higher level of cholesterol in liver compared to STI chickens (p<0.05), and CORT significantly increased hepatic cholesterol content (p<0.01). Real-time PCR results showed that both TI and CORT potentially altered ABCA1 and CYP7A1 gene expressions (0.05