Nocturnal Behavior Research Articles

Catch Me If You Can: Diel Activity Patterns of Mammalian Prey and Predators

AbstractThe activity patterns exhibited by animals are shaped by evolution, but additionally fine‐tuned by flexible responses to the environment. Predation risk and resource availability are environmental cues which influence the behavioural decisions that make both predators and prey engage in activity bursts, and depending on their local importance, can be strong enough to override the endogenous regulation of an animals’ circadian clock. In Southern Europe, wherever the European rabbit (Oryctolagus cuniculus) is abundant, it is the main prey of most mammalian mesopredators, and rodents are generally the alternative prey. We evaluated the bidirectional relation between the diel activity strategies of these mammalian mesopredators and prey coexisting in south‐western Europe. Results revealed that even though predation risk enforced by mammalian mesocarnivores during night‐time was approximately twice and five times higher than during twilight and daytime, respectively, murids consistently displayed unimodal nocturnal behaviour. Conversely, the European rabbits exhibited a bimodal pattern that peaked around sunrise and sunset. Despite the existence of some overlap between the diel rhythms of mesocarnivores and rabbits, their patterns were not synchronized. We suggest that the environmental stressors in our study areas are not severe enough to override the endogenous regulation of the circadian cycle in murids. European rabbits, however, are able to suppress their biological tendency for nocturnality by selecting a predominantly crepuscular pattern. In spite of the higher energetic input, mesocarnivores do not completely track rabbits’ activity pattern. They rather track rodents’ activity. We propose that these systems have probably evolved towards a situation where some degree of activity during high‐risk periods benefits the overall prey population survival, while the accessibility to sufficient prey prevents predators to completely track them.

Opsin Genes and Visual Ecology in a Nocturnal Folivorous Lemur

Primate color vision has traditionally been examined in the context of diurnal activity, but recent genetic and ecological studies suggest that color vision plays a role in nocturnal primate behavior and ecology as well. In this study, we united molecular analyses of cone visual pigment (opsin) genes with visual modeling analyses of food items to explore the evolution of color vision in the folivorous woolly lemur (genus Avahi). Previous studies have shown that leaf quality, e.g., protein content, leaf toughness, and protein/toughness ratio, is significantly correlated with green-red and blue-yellow chromatic differences, suggesting a potential role of color in leaf discrimination in Avahi, and, consequently, a potential adaptive advantage to color vision in this taxon. Phylogenetic selection tests determined that the strength of selection on the SWS1 opsin gene to retain blue-sensitive SWS cones did not significantly differ in Avahi compared to day-active primates. Genotyping of the M/LWS opsin gene in 60 individuals from nine species found that the 558-nm-sensitive (red-sensitive) allele is conserved across all Avahi. Finally, we measured spectral reflectance from five species of young leaves consumed by Avahi and background foliage in Ranomafana National Park and modeled performance of possible S and M/L pigment pairs for detecting these food items under different nocturnal illuminations (e.g. twilight, moonlight). We found that the observed cone pigment pair in Avahi was optimally tuned for color-based detection of young green leaves in all nocturnal light environments, suggesting a potential adaptive role of nocturnal color vision in selection for dichromacy in this genus.

Mammalian Rest/Activity Patterns Explained by Physiologically Based Modeling

Circadian rhythms are fundamental to life. In mammals, these rhythms are generated by pacemaker neurons in the suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN is remarkably consistent in structure and function between species, yet mammalian rest/activity patterns are extremely diverse, including diurnal, nocturnal, and crepuscular behaviors. Two mechanisms have been proposed to account for this diversity: (i) modulation of SCN output by downstream nuclei, and (ii) direct effects of light on activity. These two mechanisms are difficult to disentangle experimentally and their respective roles remain unknown. To address this, we developed a computational model to simulate the two mechanisms and their influence on temporal niche. In our model, SCN output is relayed via the subparaventricular zone (SPZ) to the dorsomedial hypothalamus (DMH), and thence to ventrolateral preoptic nuclei (VLPO) and lateral hypothalamus (LHA). Using this model, we generated rich phenotypes that closely resemble experimental data. Modulation of SCN output at the SPZ was found to generate a full spectrum of diurnal-to-nocturnal phenotypes. Intriguingly, we also uncovered a novel mechanism for crepuscular behavior: if DMH/VLPO and DMH/LHA projections act cooperatively, daily activity is unimodal, but if they act competitively, activity can become bimodal. In addition, we successfully reproduced diurnal/nocturnal switching in the rodent Octodon degu using coordinated inversions in both masking and circadian modulation. Finally, the model correctly predicted the SCN lesion phenotype in squirrel monkeys: loss of circadian rhythmicity and emergence of ∼4-h sleep/wake cycles. In capturing these diverse phenotypes, the model provides a powerful new framework for understanding rest/activity patterns and relating them to underlying physiology. Given the ubiquitous effects of temporal organization on all aspects of animal behavior and physiology, this study sheds light on the physiological changes required to orchestrate adaptation to various temporal niches.

Intrinsic Photosensitive Retinal Ganglion Cells in the Diurnal Rodent, Arvicanthis ansorgei

Intrinsically photosensitive retinal ganglion cells (ipRGCs) represent a new class of photoreceptors which support a variety of non-image forming physiological functions, such as circadian photoentrainment, pupillary light reflex and masking responses to light. In view of the recently proposed role of retinal inputs for the regulation of diurnal and nocturnal behavior, we performed the first deep analysis of the ipRGC system in a diurnal rodent model, Arvicanthis ansorgei , and compared the anatomical and physiological properties of ipRGCs with those of nocturnal mice. Based on somata location, stratification pattern and melanopsin expression, we identified two main ipRGC types in the retina of Arvicanthis : M1, constituting 74% of all ipRGCs and non-M1 (consisting mainly of the M2 type) constituting the following 25%. The displaced ipRGCs were rarely encountered. Phenotypical staining patterns of ganglion cell markers showed a preferential expression of Brn3 and neurofilaments in non-M1 ipRGCs. In general, the anatomical properties and molecular phenotyping of ipRGCs in Arvicanthis resemble ipRGCs of the mouse retina, however the percentage of M1 cells is considerably higher in the diurnal animal. Multi-electrode array recordings (MEA) identified in newborn retinas of Arvicanthis three response types of ipRGCs (type I, II and III) which are distinguished by their light sensitivity, response strength, latency and duration. Type I ipRGCs exhibited a high sensitivity to short light flashes and showed, contrary to mouse type I ipRGCs, robust light responses to 10 ms flashes. The morphological, molecular and physiological analysis reveals very few differences between mouse and Arvicanthis ipRGCs. These data imply that the influence of retinal inputs in defining the temporal niche could be related to a stronger cone input into ipRGCs in the cone-rich Arvicanthis retina, and to the higher sensitivity of type I ipRGCs and elevated proportion of M1 cells.

How to predict a pathologic nocturnal blood pressure behavior in parkinsonian syndromes: Red flags from tilt table testing

How to predict a pathologic nocturnal blood pressure behavior in parkinsonian syndromes: Red flags from tilt table testing

Effect of Trap Design, Chemical Lure, Carbon Dioxide Release Rate, and Source of Carbon Dioxide on Efficacy of Bed Bug Monitors

Bed bugs, (Cimex lectularius L.), are difficult to find because of their nocturnal and secretive behavior. In recent years, a number of monitors containing carbon dioxide (CO2), chemical lures, heat, or both, to attract bed bugs have been developed for detecting bed bugs. Ineffective trap design, lack of attraction of chemical lures, high cost of the CO2 delivery system, or insufficient CO release rates are some factors that limited the wide adoption of these monitors. To develop an affordable and effective monitor, we conducted a series of laboratory and field tests. Specifically, we tested a new pitfall trap design, a chemical lure mixture, different CO2 release rates, and a sugar and yeast mixture as CO2 source. Results show the new pitfall trap design was significantly more effective than Climbup insect interceptor, the most effective passive monitor available in the market for bed bugs. The experimental chemical lure mixture increased Climbup insect interceptor catch by 2.2 times. Results exhibit a distinct positive relationship between the CO2 release rates and bed bug trap catches. There were no significant differences between CO2 derived from cylinders and CO2 generated from sugar and yeast mixture in their attractiveness to bed bugs. The findings suggest an effective and affordable monitor can be made incorporating the new pitfall trap design, a sugar and yeast mixture, and a chemical lure.

A follow up study of non-demented patients with primary visual cortical hypometabolism: Prodromal dementia with Lewy bodies

We previously reported non-demented patients with glucose hypometabolism in the primary visual cortex (PVC), which is the preferentially affected region in patients with dementia with Lewy bodies (DLB). It remains unknown, however, whether these patients represent a prodromal DLB state. Eleven non-demented patients who attended our memory clinic for more than three years (mean follow-up period: 44±5months) were examined. All the patients had glucose hypometabolism in the PVC on [18F]-fluoro-d-glucose (FDG) positron emission tomography (PET) scans at baseline. Four patients, including one with a clinical history of occipital bleeding, exhibited no core or suggestive features of DLB. Seven patients reported recurrent nocturnal dream-enactment behavior, which is consistent with probable rapid eye movement (REM) sleep behavior disorder (RBD). The condition of the patient with occipital bleeding was stable, which is consistent with an underlying non-neurodegenerative disorder. Of the remaining 10 patients, 5 had stable cognitive conditions (non-converters) and 5 exhibited progression to dementia (converters). The clinical diagnoses of 4 patients with probable RBD were changed to probable DLB. Despite no differences in psychological profiles at baseline between non-converters and converters, the initial pattern of cortical metabolism differed: converters had lower glucose hypometabolism in the parietal and the lateral occipital cortex compared to non-converters. The metabolic reduction in the PVC is present in patients with prodromal DLB. Moreover, the spatial profiles of reduced glucose metabolism at baseline could help to define the distinct prognostic subgroup that has a greater risk of conversion to DLB.

Gender Differences in Subjective Sleep After Trauma and the Development of Posttraumatic Stress Disorder Symptoms: A Pilot Study

Women are at higher risk than men for developing posttraumatic stress disorder (PTSD) following certain types of trauma such as accidents and assaults. Sleep disturbances have been implicated in the development of PTSD. Although gender differences in objective sleep soon after trauma have been found in a prior polysomnographic study, gender differences in subjective sleep soon after trauma and their associations to the development of PTSD have not been examined. This pilot study prospectively examined whether gender moderated the relationship between subjective sleep soon after trauma and PTSD symptom development. Injury patients (17 women, 28 men) completed a sleep questionnaire and a 1-week sleep diary 2 weeks after their injuries, and the Clinician Administered PTSD Scale at 7-weeks postinjury. Results showed that women reported greater frequency of nightmares and disruptive nocturnal behaviors (e.g., hot flashes, memories/nightmares about trauma) following the trauma and more severe PTSD symptoms at 7 weeks. Further, gender moderated the relationship between sleep-onset latency and PTSD symptom severity, such that longer sleep-onset latency predicted more severe PTSD symptoms in men, but less severe PTSD symptoms in women. These findings suggest that gender-specific mechanisms may underlie the relationship between sleep impairment and the development of PTSD.

Short communication: Assessment of activity patterns of growing rabbits in a flux-controlled chamber

Flux-controlled and metabolic chambers are often used for nutritional and environmental studies. However, the potential alterations of animal behaviour and welfare are so far not fully understood. In consequence, this study had 2 main objectives: to assess potential alterations of animal activity pattern and time budget inside a flux chamber, and to assess the importance of the “rearing up” behaviour. To this end, 10 growing rabbits of different ages (from 1 to 5 wk of the growing period) were housed inside a flux chamber. Their activity was continuously recorded and assessed, determining the frequency and duration of 8 different behaviours: lying, sleeping, sitting, eating, drinking, walking, rearing up and others. Nocturnal rabbit behaviour and time budget were not altered inside the chamber if compared to previously described rabbit activity under conventional cages. In addition, rabbits in this experiment presented a tendency to perform “rearing up” when housed inside the flux chamber.

Epibenthic assemblages in the Celtic Sea and associated with the Jones Bank

The epibenthic assemblages in the Celtic Sea are described from the catches from 2m beam trawl surveys undertaken from 2000 to 2009. During this period 154 samples were collected. The most ubiquitous species in the study area were the natantid shrimps Processa spp. and Crangon allmanni, the hermit crabs Pagurus prideaux and Anapagurus laevis, sand star Astropecten irregularis and spotted dragonet Callionymus maculatus. Multivariate community analyses indicated that catches (numbers per tow) were distributed across six assemblages, two of which were predominant in the study area. Most catches were attributed to either a ‘shelf edge assemblage‘, which was widespread in deeper waters (114–423m water depth) or an ‘outer shelf assemblage’ that occurred across much of the Celtic Sea north of 49°N in waters 49–175m deep. The dominant species along the edge of the continental shelf were the hormathid anemome Actinauge richardi, sea spider Pycnogonum littorale (which associated with A. richardi), Devonshire cup coral Caryophyllia smithii and the swimming crab Macropipus tuberculatus. The dominant species in the outer shelf assemblage included P. prideaux, C. allmanni, A. laevis and common starfish Asterias rubens. Stations closer to shore were relatively distinct and catches in this ‘inner shelf assemblage’ were composed primarily of an inshore fauna (e.g. Ophiura ophiura, C. allmanni and Liocarcinus holsatus). Stations in the southern part of the survey grid were also relatively distinct (‘southern Celtic Sea assemblage’), and several large echinoderms (Porania pulvillus, Stichastrella rosea and Anseropoda placenta) dominated at these sites. Three of the deepest stations were also relatively distinct, as were a group of stations in the muddy habitat of the Celtic Deep and comparable grounds elsewhere in the region, where Nucula sulcata and Alpheus glaber were characteristic. Catches on the shallower parts of the Jones Bank (and on another bank in the region) were dominated by the anemone Paraphellia expansa, with off-bank sites comprising a greater number of species. In contrast to beam trawl sampling, baited camera observations on the Jones Bank showed a greater richness of species on the shallower part of the bank, and provided information on the nocturnal feeding behaviour of scavenging isopods.

Habitat use by southern forest geckos (Mokopirirakau ‘Southern Forest’) in the Catlins, Southland

Basic biological information is critical to evaluating conservation requirements for native taxa, but is lacking for many cryptic New Zealand lizard species. Southern forest geckos (Mokopirirakau ‘Southern Forest’) are known only from anecdotes, museum specimens and discoveries of an individual at each of three sites during recent surveys in the Catlins. We used systematic searching, photo identification and radio telemetry at one of these sites (Tahakopa Valley) to investigate habitat use of southern forest geckos. Forty-five hours of searching in 2010–2011 yielded 28 sightings of 17 individuals including four juveniles (indicating that a breeding population exists). Most geckos were found by searching a boulder used as a diurnal retreat site or in mānuka (Leptospermum scoparium). Two geckos were radio-tracked; both remained within 5 m of capture and exhibited primarily nocturnal behaviour. We recommend further survey work to identify populations and monitoring to evaluate the need for conservation intervention.

Diurnal and Nocturnal Behaviour of Airborne Cryptomeria japonica Pollen Grains and the Allergenic Species in Urban Atmosphere of Saitama, Japan

Japanese cedar (Cryptomeria japonica) pollinosis is the most popular pollinosis in Japan. It has been reported that Cryptomeria japonica pollen allergenic species are suspended as fine particles in the urban atmosphere. These allergenic fine particles are responsible for inducing asthma by breaking into the lower respiratory tract. It has also been found that pollinosis symptoms on the sufferers appear mainly at night-time by the results from epidemiological studies. However, the exact reason for these phenomena is not yet clarified. In this study, the diurnal and nocturnal behaviours of Cryptomeria japonica pollen grains and their allergenic species in the urban area of Saitama city of Kanto Plain were investigated. Airborne pollen grains and allergenic Cry j 1 concentrations in total suspended particulate matter (TSP) were investigated at two sampling sites, a heavy traffic road (roadside site) and at the balcony of the <TEX>$10^{th}$</TEX> floor of the Building of Research and Project of Saitama University (general urban site). The latter sampling site where located about 300 m away from the roadside site was used as a general urban site unaffected by automobile traffic. The airborne pollen counts were measured with a real-time pollen monitor. Cry j 1 particles were collected with two high volume air samplers, and these concentrations were measured by surface plasmon resonance method with a Biacore J system. The diurnal variation of the airborne pollen counts was similar to the trends of temperature and wind speed during the day-time; whereas its tendency with wind speed trend was not observed during the night-time. Airborne pollen counts were lower with northern wind than with southern wind because the pollen comes from the mountainous areas, and the mountains in the south are closer, about half the distance to the northern mountains. It is suggested that the peaks of airborne pollen counts during night-time in the sampling site occurred by transport of pollen grains released during day-time in the mountainous forest areas, located c.a. 100 km away from the sampling site. On the roadside site the allergenic Cry j 1 concentrations were higher than at the general urban site, nevertheless pollen grains counts were lower. These results suggested that worsening of pollinosis symptoms during night-time in urban area was caused by transport of pollen grains during day-time in the mountainous forest areas. Moreover, pollen allergenic species become different morphology from pollen grain at roadside site, and the subsequent pollen grains re-suspension by automobile traffic.

The effect of night illumination, red and infrared light, on locomotor activity, behaviour and melatonin of Senegalese sole (Solea senegalensis) broodstock

The present study aimed to determine a non-invasive nocturnal lighting system for the behavioural observation of a highly light sensitive species, Senegalese sole (Solea senegalensis). Locomotor activity, four types of behaviour and plasma melatonin were analysed in groups of 12 adult Senegalese sole (Solea senegalensis) reared in captivity and held under four night illumination treatments: total darkness (control), high 50lux intensity red light (group RH), low 5lux intensity red light (group RL) and infrared light (group IR). All groups experienced the same conditions during the day (lights on from 07:00 to 19:00) with white lighting of 125lux. Clarity of video images taken at night for the observation of fish behaviour were ranked as follows: group RH>RL>IR>control. All treatments presented a daily rhythm in locomotor activity with high activity from 14:00 to 18:00 and low activity from 21:00 to 12:00. The sole exposed to the high intensity red light at night appeared to be disturbed as during the low nocturnal locomotor activity period group RH presented higher activity and significantly higher nocturnal behaviour related to escape or fear than was observed in the other groups. The groups control, RL and IR exhibited similar levels of nocturnal locomotor activity and nocturnal behaviour related to escape or fear. Plasma melatonin, at mid-dark was not significantly different between the control and groups RL and IR, while melatonin was significantly lower in group RH compared to the control. The authors recommended low intensity red night illumination for the non-invasive study of nocturnal behaviour of Senegalese sole adults.

Colour, confusion, and crossing: resolution of species problems inBohadschia(Echinodermata: Holothuroidea)

Sea cucumbers of the genus Bohadschia (Holothuroidea: Echinodermata) are among the larger and more common echinoderms on tropical coral reefs. While the genus is easy to identify and has been recognized for some time, the number and status of species have varied substantially for over a century. The species problem in Bohadschia is the result of high intra-specific variability and little inter-specific divergence in the principal, traditional taxonomic characters, the shape and size of microscopic dermal ossicles. We re-evaluate Bohadschia primarily based on colour pattern of living animals and mitochondrial sequence data. The character sets are congruent, and both cleanly delineate 11 species and one common hybrid form. The vexing Bohadschia marmorata complex is resolved into four species, all of which have available names, although two have not been recognized correctly since their description. A fairly common colour form intermediate between B. argus and B. vitiensis has mtDNA sequences matching either one or the other species and is interpreted as a hybrid form. Several species occur sympatrically at most locations; however, the most closely related species show evidence of allopatric divergence. Character state reconstructions suggest that the prevalent diurnal burrowing and nocturnal epibenthic feeding behaviour among Bohadschia evolved early in the history of the genus. Ossicle shape and size were found to perform poorly in distinguishing species, while colour pattern is diagnostic.

Validation of the Pittsburgh Sleep Quality Index Addendum for Posttraumatic Stress Disorder (PSQI‐A) in U.S. Male Military Veterans

Sleep disturbances are core symptoms of posttraumatic-stress disorder (PTSD), yet they bear less stigma than other PTSD symptoms. Given the growing number of returning military veterans, brief, valid assessments that identify PTSD in a minimally stigmatizing way may be useful in research and clinical practice. The study purpose was to evaluate the psychometric properties of the Pittsburgh Sleep Quality Index Addendum for PTSD (PSQI-A), and to examine its ability to identify PTSD cases among U.S. male military veterans. Male military veterans (N = 119) completed the PSQI-A, as well as measures of sleep quality, combat exposure, posttraumatic stress, depression, and anxiety. Veterans with PTSD had higher PSQI-A identified disruptive nocturnal behaviors than veterans without PTSD. The PSQI-A had good internal consistency and convergent validity with sleep quality, combat exposure, PTSD symptoms, depression, and anxiety. A cutoff score ≥ 4 provided an area under the curve = .81, with 71% sensitivity, 82% specificity, and 60% positive and 83% negative predictive value for a clinical diagnosis of PTSD; correct classification was 74%. The PSQI-A is a valid measure to possibly detect PTSD among male military veterans. Assessment of disruptive nocturnal behaviors may provide a cost-effective, nonstigmatizing approach to PTSD screening without directly probing for trauma exposure(s).

Investigating frequency and duration of nocturnal ingestive and sleep behaviors of horses bedded on straw versus shavings

Investigating frequency and duration of nocturnal ingestive and sleep behaviors of horses bedded on straw versus shavings

Effects of Temperature, Moon Phase, and Prey on Nocturnal Activity in Ratsnakes: An Automated Telemetry Study

Abstract Nocturnal activity is important for many animals, but difficulty in documenting that activity has hampered efforts to understand factors that influence when animals are active at night. We used automated radiotelemetry to provide the first detailed tests of the hypothesis that the nocturnal activity of free-ranging snakes should be influenced by temperature, moon phase, and prey abundance by using data for Ratsnakes (Pantherophis spp.) from Texas and Illinois. Ratsnakes exhibited some nocturnal behavior throughout their active season in both Texas and Illinois, although snakes were much more active at night in Texas than in Illinois. Texas snakes transitioned from primarily diurnal activity to primarily nocturnal activity over this snake's active season, whereas Illinois snakes were always most active in the middle of the day. For both populations, nocturnal activity was positively related to temperature but unrelated to moon phase. Ratsnakes in Texas exhibited a stepwise increase in nocturnal ac...

Patterns of Lacewing (Neuroptera: Chrysopidae) Flight Activity, Flight Height and Spatial Distribution of Eggs on Maize Plants

Lacewings (Chrysopidae) are important beneficial insects in nearly all cropping systems. However, monitoring of lacewing numbers is difficult due to the nocturnal behaviour of adults and the difficulty of finding eggs and larvae on plants. Techniques facilitating easy finding of eggs and adults will result in improved pest management decisions and monitoring of these beneficial organisms. This study was conducted to determine flight activity patterns as well as preferred oviposition sites of lacewings on maize plants to facilitate time-effective searching for eggs. The daily flight activity pattern and flight height of lacewings were recorded and sweep-net samples were taken to determine lacewing numbers in different adjacent vegetation types (maize, lucerne, natural veld). The preferred area of oviposition was determined by inspecting maize plants for lacewing eggs and recording the distribution of eggs on leaves. Chrysoperla pudica (Navas) was the predominant species in maize. Lacewings were most active between 16:00 and 22:00 and flew largely between 0.5 and 2.5 m above ground level. Oviposition occurred predominantly on leaves near maize ears. Data on spatial distribution of eggs facilitate monitoring of eggs numbers in maize cropping systems and is also of use in general pest management.

Anemonefish oxygenate their anemone hosts at night

Many stony coral-dwelling fishes exhibit adaptations to deal with hypoxia among the branches of their hosts; however, no information exists on the respiratory ecophysiology of obligate fish associates of non-coral organisms such as sea anemones and sponges. This study investigated metabolic and behavioral interactions between two-band anemonefish (Amphiprion bicinctus) and bulb-tentacle sea anemones (Entacmaea quadricolor) at night. We measured the net dark oxygen uptake ( , μmol O2 h(-1)) of fish-anemone pairs when partners were separate from each other, together as a unit, and together as a unit but separated by a mesh screen that prevented physical contact. We also measured the effects of water current on sea anemone and quantified the nocturnal behaviors of fish in the absence and presence of host anemones in order to discern the impacts of anemone presence on fish behavior. Net of united pairs was significantly higher than that of both separated pairs and united pairs that were separated by a mesh screen. Anemone increased with flow rate from 0.5 to 2.0 cm s(-1), after which remained constant up to a water flow rate of 8.0 cm s(-1). Furthermore, the percentage time and bout frequency of flow-modulating behaviors by fish increased significantly when anemones were present. We conclude that physical contact between anemonefish and sea anemones elevates the of at least one of the partners at night, and anemonefish behavior at night appears to oxygenate sea anemone hosts and to augment the metabolism of both partners.

Long-term impact of earthquakes on sleep quality.

PurposeWe investigated the impact of the 6.3 magnitude 2009 L’Aquila (Italy) earthquake on standardized self-report measures of sleep quality (Pittsburgh Sleep Quality Index, PSQI) and frequency of disruptive nocturnal behaviours (Pittsburgh Sleep Quality Index-Addendum, PSQI-A) two years after the natural disaster.MethodsSelf-reported sleep quality was assessed in 665 L’Aquila citizens exposed to the earthquake compared with a different sample (n = 754) of L'Aquila citizens tested 24 months before the earthquake. In addition, sleep quality and disruptive nocturnal behaviours (DNB) of people exposed to the traumatic experience were compared with people that in the same period lived in different areas ranging between 40 and 115 km from the earthquake epicenter (n = 3574).ResultsThe comparison between L’Aquila citizens before and after the earthquake showed a significant deterioration of sleep quality after the exposure to the trauma. In addition, two years after the earthquake L'Aquila citizens showed the highest PSQI scores and the highest incidence of DNB compared to subjects living in the surroundings. Interestingly, above-the-threshold PSQI scores were found in the participants living within 70 km from the epicenter, while trauma-related DNBs were found in people living in a range of 40 km. Multiple regressions confirmed that proximity to the epicenter is predictive of sleep disturbances and DNB, also suggesting a possible mediating effect of depression on PSQI scores.ConclusionsThe psychological effects of an earthquake may be much more pervasive and long-lasting of its building destruction, lasting for years and involving a much larger population. A reduced sleep quality and an increased frequency of DNB after two years may be a risk factor for the development of depression and posttraumatic stress disorder.