Diurnal Behavior Research Articles

Thermal performance analysis of PCM-integrated structures using the resistance-capacitance model: Experiments and numerics

While holding significant potential to reduce cooling energy requirements in buildings, the incorporation of phase-change materials in building envelopes requires information regarding their diurnal and seasonal behaviour through high-fidelity simulations. However, utilizing short-term simulations and experimentation using state-of-the-art models for such a complex configuration does not accurately represent the true heat transfer dynamics of the building. To address this lacuna, we present a physics-based, low computational cost, experimentally and numerically validated resistance–capacitance (RC) model specifically tailored for PCM-encapsulated structures, designed for long-term simulations. The validation of this model is conducted through in-house experiments. Additionally, we support the credibility of our RC model by subjecting it to validation through 3D numerical simulations, emphasizing its precision and reliability. Then, we use the validated model to optimize the thermal properties of concrete roofs in hot and dry climates, taking a specific instance of a city in Western India for various geometric configurations as an illustrative example. We find that a PCM with a phase change temperature between 37 and 42 °C can reduce the peak ceiling temperature by up to 10 °C and the peak energy ingress by a factor of 2 or more, in a typical roof element subjected to the prevailing climatic conditions during peak summer. This shows the time constant of the modified roof is effective in delaying and damping the imposed solar insolation. We make specific recommendations on the selection and geometry optimization of PCM-incorporated roof elements.

Early Morning Activity: New records of diurnal behavior in Mexican bats

Bats are predominantly nocturnal animals, but some studies, mainly from temperate regions and islands, report bats flying during the day. We report the diurnal foraging of three species of bats in Mexico, one species of the family Vespertilionidae, and two Phyllostomidae (Anoura and Artibeus). In addition, we document the first in situ record of fruit consumption on the ground for Artibeus. Diurnal flight in bats is a poorly documented behavior in the tropics. Furthermore, we suggest that extreme heat and drought may influence this behavior, as two reports occurred during periods of drought.

The diurnal variation of dust and water ice aerosol optical depth at Jezero crater observed by MEDA/TIRS over a full Martian year

The Thermal InfraRed Sensor (TIRS) on the Perseverance rover has provided nearly two full Mars years of systematic monitoring of the total aerosol optical depth above Jezero Crater. These observations span a wide range of timescales, capturing seasonal patterns, diurnal variations, and minute-to-minute fluctuations in aerosol loading. By combining TIRS retrievals with orbital observations, the relative contributions of dust and water ice aerosols can be estimated, revealing their different seasonal and diurnal behaviors. The TIRS record shows distinct periods of dust storm activity, including strong regional storms during the perihelion season as well as short-lived but intense dust events outside the typical dust storm season. Water ice clouds exhibit pronounced seasonal and diurnal variability, with peak activity occurring during the aphelion season but with a presence throughout the year. The diurnal variation of clouds differs significantly between the aphelion and perihelion seasons, with clouds persisting throughout the night during the aphelion season, while largely absent outside of specific periods after sunrise and sunset during the perihelion season. These results provide new insights into the complex behavior of aerosols at Jezero Crater and their connections to atmospheric dynamics and the Martian dust and water cycles.

Chromosome-level genome assembly of the forest pest Achelura yunnanensis (Lepidoptera: Zygaenidae)

Achelura yunnanensis is a destructive pest of forests, causing substantial damage on tree growth and severe economic losses. Additionally, as a daytime-active moth, this species also holds important scientific value for investigating the genetic mechanisms governing day-night activity patterns of Lepidoptera. To facilitate effective pest control and deepen our understanding of the diurnal behavior’s genetic basis of moths, genomic data for this species are crucial. In this study, we present a chromosome-level reference genome of A. yunnanensis (368.15 Mb in 32 chromosomes; scaffold N50 = 12.61 Mb; BUSCO completeness = 98.0%). Genome annotation shows that the new assembly comprises 37.10% (136.55 Mb) repetitive elements, 1,828 non-coding RNAs, and 15,523 protein-coding genes. Genes involved in lipid metabolism and xenobiotics biodegradation and metabolism, such as cytochrome P450 families, experienced significant expansion in the A. yunnanensis genome. The chromosome-level genome of A. yunnanensis provides a valuable genomic resource for devising novel pest control strategies, and will also help to study the genetic mechanism of the shift of diurnal behavior in Lepidoptera.

Probing the D-region ionosphere globally with Earth Networks Total Lightning Network data

An existing technique to use broadband lightning waveforms to probe the D-region ionosphere (60–90 km altitude) is shown to be extendable to a global scale using the Earth Networks Total Lightning Network (ENTLN). This paper demonstrates the technique in detail on a region of the Southeastern United States. This demonstration shows that diurnal D-region height variation and smaller time-scale variations on the order of tens of minutes to hours are evident in the measurement. The technique is then extended to three additional global regions on this same day: Northeastern U.S., India, and Japan. The diurnal behavior between these different regions is compared to a D-region model from the International Reference Ionosphere.

Seasonal changes in the diurnal behavior of Chimarrogale platycephalus evaluated using environmental DNA

Seasonal changes in the diurnal behavior of Chimarrogale platycephalus evaluated using environmental DNA

Seasonal Influence on the Diurnal Behaviours of the Indian Flying Fox (Pteropus medius) in Lucknow, India

Seasonal Influence on the Diurnal Behaviours of the Indian Flying Fox (Pteropus medius) in Lucknow, India

Sweetened caffeine drinking revealed behavioral rhythm independent of the central circadian clock in male mice

Caffeine consumption is associated with the evening chronotype, and caffeine administration in mice results in prolonged period of the circadian rhythm in locomotor activity. However, as caffeine is bitter, sweetened caffeine is preferred by humans and mice; yet, its impact on the circadian clock has not been explored. In this study, mice were provided with freely available sweetened caffeine to investigate its effects on behavioral rhythms and peripheral clocks. Mice that freely consumed sweetened caffeine shifted from nocturnal to diurnal activity rhythms. In addition to the light-dark entrained behavioral rhythm component, some animals exhibited free-running period longer than 24-h. Intraperitoneal administration of caffeine at the beginning of the light phase also acutely induced diurnal behavior. The behavioral rhythms with long period (26–30 h) due to sweetened caffeine were observed even in mice housed under constant light or with a lesioned central circadian clock located in the suprachiasmatic nucleus of the hypothalamus; however, the rhythmicity was unstable. PER2::LUCIFERASE rhythms in peripheral tissues, such as the kidney, as measured via in vivo whole-body imaging during caffeine consumption, showed reduced amplitude and desynchronized phases among individuals. These results indicate that consumption of sweetened caffeine induces diurnal and long-period behavioral rhythms irrespective of the central clock, causing desynchronization of the clock in the body.

Temporal patterns in dolphin foraging activity in the Mediterranean Sea: insights from vocalisations recorded during the ACCOBAMS Survey Initiative

Marine organisms continually adapt their physiology and behaviour to temporal variations in their environment, resulting in diurnal rhythmic behaviour, particularly when foraging. In delphinids, these rhythms can be studied by recording echolocation clicks, which can provide indicators of foraging activity. The foraging rhythms of delphinids and their relationship to temporal parameters are poorly documented and most studies so far have used moored passive acoustic systems. The present study provides, for the first time, information on the activity rhythms of delphinids investigated in relation with temporal variables at a basin scale from a moving platform, in the western and central Mediterranean Sea. We used passive acoustic recordings collected by hydrophones towed along transect lines during the ACCOBAMS Survey Initiative in the summer 2018. We extracted variables that may influence daily and monthly rhythms, including time of day, lunar cycle, lunar illumination and sea state and fitted generalised additive models. The nycthemeral and lunar cycles were the two main factors influencing dolphin activity rhythms. Echolocation activity was predominant at night, with a maximum of 0.026 acoustic events per minute at 21:00/22:00 compared to as few as 0.0007 events per minute at 11:00. These events were also more frequent during the third quarter of the moon; 0.033 acoustic events on day 22 of the lunar cycle as opposed to 0.0008 on day 8 of the lunar cycle, corresponding to the first quarter of the moon. Variations in the echolocation activity of delphinids in the Mediterranean Sea could reflect variation in their foraging effort and be related to prey density, composition, accessibility and catchability within dolphin foraging depth range. These results should also improve interpretation of passive acoustic monitoring data.

The Estrous Cycle Coordinates the Circadian Rhythm of Eating Behavior in Mice.

The estrous cycle regulates rhythms of locomotor activity, body temperature, and circadian gene expression. In female mice, activity increases on the night of proestrus, when elevated estrogens cause ovulation. Exogenous estradiol regulates eating behavior rhythms in female mice fed a high-fat diet, but it is unknown whether endogenous estrogens regulate eating rhythms. In this study, we investigated whether diurnal and circadian eating behavior rhythms change systematically across the estrous cycle. We first studied diurnal eating behavior rhythms in female C57BL/6J mice in 12L:12D. Estrous cycle stages were determined by vaginal cytology while eating behavior and wheel revolutions were continuously measured. The mice had regular 4- to 5-day estrous cycles. Consistent with prior studies, the greatest number of wheel revolutions occurred on the night of proestrus into estrus when systemic levels of estrogens peak. The amplitude, or robustness, of the eating behavior rhythm also fluctuated with 4- to 5-day cycles and peaked primarily during proestrus or estrus. The phases of eating behavior rhythms fluctuated, but not at 4- or 5-day intervals, and phases did not correlate with estrous cycle stages. After ovariectomy, the eating behavior rhythm amplitude fluctuated at irregular intervals. In constant darkness, the amplitude of the circadian eating behavior rhythm peaked every 4 or 5 days and coincided with the circadian day that had the greatest number of wheel revolutions, a marker of proestrus. These data suggest that fluctuations of ovarian hormones across the estrous cycle temporally organize the robustness of circadian eating behavior rhythms so that it peaks during ovulation and sexual receptivity.

Systemic Inflammation Disrupts Circadian Rhythms and Diurnal Neuroimmune Dynamics.

Circadian rhythms regulate physiological processes in approximately 24 h cycles, and their disruption is associated with various diseases. Inflammation may perturb circadian rhythms, though these interactions remain unclear. This study examined whether systemic inflammation induced by an intraperitoneal injection of lipopolysaccharide (LPS) could alter central and peripheral circadian rhythms and diurnal neuroimmune dynamics. Mice were randomly assigned to two groups: the saline control group and the LPS group. The diurnal expression of circadian clock genes and inflammatory cytokines were measured in the hypothalamus, hippocampus, and liver. Diurnal dynamic behaviors of microglia were also assessed. Our results revealed that the LPS perturbed circadian gene oscillations in the hypothalamus, hippocampus, and liver. Furthermore, systemic inflammation induced by the LPS could trigger neuroinflammation and perturb the diurnal dynamic behavior of microglia in the hippocampus. These findings shed light on the intricate link between inflammation and circadian disruption, underscoring their significance in relation to neurodegenerative diseases.

Development of a Novel Classification Approach for Cow Behavior Analysis Using Tracking Data and Unsupervised Machine Learning Techniques.

Global Positioning Systems (GPSs) can collect tracking data to remotely monitor livestock well-being and pasture use. Supervised machine learning requires behavioral observations of monitored animals to identify changes in behavior, which is labor-intensive. Our goal was to identify animal behaviors automatically without using human observations. We designed a novel framework using unsupervised learning techniques. The framework contains two steps. The first step segments cattle tracking data using state-of-the-art time series segmentation algorithms, and the second step groups segments into clusters and then labels the clusters. To evaluate the applicability of our proposed framework, we utilized GPS tracking data collected from five cows in a 1096 ha rangeland pasture. Cow movement pathways were grouped into six behavior clusters based on velocity (m/min) and distance from water. Again, using velocity, these six clusters were classified into walking, grazing, and resting behaviors. The mean velocity for predicted walking and grazing and resting behavior was 44, 13 and 2 min/min, respectively, which is similar to other research. Predicted diurnal behavior patterns showed two primary grazing bouts during early morning and evening, like in other studies. Our study demonstrates that the proposed two-step framework can use unlabeled GPS tracking data to predict cattle behavior without human observations.

The potential role of the Asian bush mosquito Aedes japonicus as spillover vector for West Nile virus in the Netherlands

BackgroundIn recent years the Asian bush mosquito Aedes japonicus has invaded Europe, including the Netherlands. This species is a known vector for a range of arboviruses, possibly including West Nile virus (WNV). As WNV emerged in the Netherlands in 2020, it is important to investigate the vectorial capacity of mosquito species present in the Netherlands to estimate the risk of future outbreaks and further spread of the virus. Therefore, this study evaluates the potential role of Ae. japonicus in WNV transmission and spillover from birds to dead-end hosts in the Netherlands.MethodsWe conducted human landing collections in allotment gardens (Lelystad, the Netherlands) in June, August and September 2021 to study the diurnal and seasonal host-seeking behaviour of Ae. japonicus. Furthermore, their host preference in relation to birds using live chicken-baited traps was investigated. Vector competence of field-collected Ae. japonicus mosquitoes for two isolates of WNV at two different temperatures was determined. Based on the data generated from these studies, we developed a Susceptible-Exposed-Infectious-Recovered (SEIR) model to calculate the risk of WNV spillover from birds to humans via Ae. japonicus, under the condition that the virus is introduced and circulates in an enzootic cycle in a given area.ResultsOur results show that Ae. japonicus mosquitoes are actively host seeking throughout the day, with peaks in activity in the morning and evening. Their abundance in August was higher than in June and September. For the host-preference experiment, we documented a small number of mosquitoes feeding on birds: only six blood-fed females were caught over 4 full days of sampling. Finally, our vector competence experiments with Ae. japonicus compared to its natural vector Culex pipiens showed a higher infection and transmission rate when infected with a local, Dutch, WNV isolate compared to a Greek isolate of the virus. Interestingly, we also found a small number of infected Cx. pipiens males with virus-positive leg and saliva samples.ConclusionsCombining the field and laboratory derived data, our model predicts that Ae. japonicus could act as a spillover vector for WNV and could be responsible for a high initial invasion risk of WNV when present in large numbers.Graphical

Group structure and diurnal behavior in a large colony of Mimon cozumelae in Yucatán, México.

Group structure and diurnal behavior in a large colony of Mimon cozumelae in Yucatán, México.

Reduced human disturbance increases diurnal activity in wolves, but not Eurasian lynx

Wildlife in the Anthropocene is increasingly spatially and temporally constrained by lethal and non-lethal human disturbance. For large carnivores with extensive space requirements, like wolves and Eurasian lynx, avoiding human disturbance in European landscapes is challenging when sufficient space with low disturbance is rarely available. Consequently, investigating behavioural adjustments to human presence is critical to understanding the capacity to adapt to human disturbance. We hypothesised that under low human disturbance conditions, large carnivores would adjust their temporal behaviours to make use of daytime, and when daytime human disturbance is high, they would opt for nocturnality. Using camera trap data from nine European study sites along a gradient in human disturbance, we analysed wolf and Eurasian lynx activity patterns. Our data spanned multiple years, 2014 – 2022, and we focused our analysis on September until April, when most large carnivore monitoring takes place. For wolves, our analysis revealed i) increased nocturnal behaviour, ii) decreased diurnal overlap with increasing human activity, and iii) a significant association between a higher probability of nocturnal activity and increasing human disturbance. For Eurasian lynx, we found iv) consistently nocturnal behaviours across all study sites, regardless of human disturbance, and v) no association between human disturbance and increased probability of being active during the night. Our results show that wolves can adjust to diurnal or cathemeral behaviours under low human disturbance, but shift to nocturnality when human disturbance increases. Eurasian lynx, however, consistently maintain their nocturnal behaviour, which we attribute to their principal hunting strategy of stalk and ambush. If human disturbance constrains large carnivore activity to nighttime, it could influence their interactions with prey, leading to cascading effects in the ecosystem. On the other hand, maintaining nocturnal behaviours in human-dominated landscapes may benefit large carnivore conservation, by decreasing negative interactions with humans thereby contributing to a landscape of coexistence.

Temporal pattern in foraging behaviour of Vanellus malabaricus in relation to different seasons and habitats

This study monitored the temporal pattern of the diurnal foraging behaviour of yellow-wattled lapwing Vanellus malabaricus Boddaert, 1783 (Charadriiformes: Charadriidae) in different seasons (breeding and non-breeding) and habitats (uncultivated, cultivated, ponds and rivers). The focal observation method was employed to investigate the foraging behaviours of yellow-wattled lapwings. Foraging techniques showed non-significant (p = 0.85) variation in different habitat types; however, walk-halt pecking (WHP) was observed to be the most commonly utilized foraging technique across all habitats. Furthermore, foraging success varied significantly in seasons (p <0.05) as well as in habitat types (p <0.05). Due to the availability of ample food items, foraging success reached its peak in uncultivated habitats. We documented considerably high feeding rates in the uncultivated habitat in the breeding season due to the high prey abundance. Additionally, seasons and habitat both greatly affected the rate of walking. Uncultivated habitat represented the highest value of % successful attempts while the lowest value of % successful attempts was recorded in river habitat. Moreover, the % successful attempts were significant (p <0.05) in the breading season as compared to the non-breeding season. Finally, we found substantial (p <0.05) changes in temporal pattern with regard to daily foraging behaviour. The behaviours appear to be bimodal, with morning and evening types for both seasons and habitat types.

Evaluation of Wildfire Plume Injection Heights Estimated from Operational Weather Radar Observations Using Airborne Lidar Retrievals

AbstractThe vertical distribution of wildfire smoke aerosols is important in determining its environmental impacts but existing observations of smoke heights generally do not possess the temporal resolution required to fully resolve the diurnal behavior of wildfire smoke injection. We use Weather Surveillance Radar‐1988 Doppler (WSR‐88D) dual polarization data to estimate injection heights of Biomass Burning Debris (BBD) generated by fires. We detect BBD as a surrogate for smoke aerosols, which are often collocated with BBD near the fire but are not within the size range detectable by these radars. Injection heights of BBD are derived for 2–10 August 2019, using WSR‐88D reflectivity (Z ≥ 10 dBZ) and dual polarization correlation coefficients (0.2 < C.C < 0.9) to study the Williams Flats fire. Results show the expected diurnal cycles with maximum injection heights present during the late afternoon period when the fire's intensity and convective mixing are maximized. WSR‐88D and airborne lidar injection height comparisons reveal that this method is sensitive to outliers and generally overpredicts maximum heights by 40%, though mean and median heights are better captured (<20% mean error). WSR‐88D heights between the 75th and 90th percentile seem to accurately represent the maximum heights, with the exception of heights estimated during the occurrence of a pyro‐cumulonimbus. Location specific mapping of WSR‐88D and lidar injection heights reveal that they diverge further away from the fire as expected due to BBD settling. Most importantly, WSR‐88D‐derived injection height estimates provide near continuous smoke height information, allowing for the study of diurnal variability of smoke injections.

Changes in Behavior and Diel Melatonin Secretion Toward Estivation in Western Sand Lance, Ammodytes japonicus (Uranoscopiformes, Ammodytidae).

Western sand lance, Ammodytes japonicus, is known to have an estivation period, in which they cease feeding and stay in the sand from early summer to late autumn, followed by gonadal maturation. During the feeding period prior to estivation, they swim in daytime and spend the night in the sand. Before they start swimming, they show a typical behavior of head-exposing from the sand, which is likely to be related to foraging and predation avoidance. Our previous study revealed that melatonin regulates such diel behavior of this species. To elucidate the mechanisms of behavioral regulation throughout the life cycle of this sand lance, the present study examined the changes in behavior and melatonin secretion toward the estivation period. Both head-exposing and swimming behaviors were frequently observed at the transition period toward estivation. On the other hand, occurrence of these behaviors was suppressed just before entering estivation. Subsequently, it was found that plasma melatonin concentration was about three times higher at night than in daytime in the non-estivation period, while it was retained at high levels throughout the day in the estivation period. These results indicate that diurnal swimming behavior of sand lance from the feeding to estivation periods is associated with the daily cycle of melatonin secretion.

Stomach contents of a road-killed Jaguarundi Herpailurus yagouaroundi in Hidalgo, Mexico

ABSTRACT Studies on the diet of the Jaguarundi are scarce; it feeds on small mammals, birds, and, to a lesser extent, fruits, reptiles, arthropods, and fish. We report eight food items for the species based on a review of the stomach contents of a female roadkill. We found the records of the snake Drymobius margaritiferus, the lizard Sceloporus sp., the rodent Sigmodon toltecus (two individuals), Passeriformes birds (three), and another snake belonging to Colubridae. A review of 11 other studies of jaguarundi food habits in Mexico and Brazil documents 120 food items, 59% of which are mammals, and most items reflect the diurnal behavior of the species.

Insights into swordfish (Xiphias gladius) movement patterns and habitat utilization off the coast of northern Chile

This study reports on the fine-scale movements of swordfish (Xiphias gladius) tagged off of the Antofagasta region of northern Chile, where harpoon fishing operations date back more than seven millenia. The study was conducted within a highly productive swordfish foraging area where movements and habitat use remain poorly characterized. Swordfish were outfitted with both data storage and satellite-linked archival tags scheduled for short (<30 days) and longer-term (>100 days) data collection. All tags were deployed on basking swordfish using harpoon-based methods across two field seasons in March 2019 and April 2022 around oceanic fronts and offshore seamounts. Fine-scale depth and temperature data were recorded over 145 days from four adult swordfish (100-200 kg). Swordfish exhibited regionally unique diurnal behaviors with greater average daytime depths than those recorded at night (78.0 ± 66.5 and 12.7 ± 4.9 m, respectively). The average daytime depths were shallower than those previously documented for other Pacific regions, including Chile's offshore waters. Daytime basking was observed on 76% of the daily records (110 out of 145 days) and accounted for approximately 12% of the collective daylight hours. Findings align with previous swordfish tagging studies and suggest that depth distribution patterns vary considerably depending on regional oceanographic conditions. Movement data are compared with previous studies, and we discussed relative to regional fishing operations.