Search Results (78)

The circadian clock is a self-sustaining oscillator with a period of approximately 24 h, enabling organisms to anticipate daily recurring events, such as sunrise and sunset. Since the circadian period is not exactly 24 h and the environmental day length varies throughout the year, the clock must be periodically reset to align an organism’s physiology with the natural light/dark cycle. This synchronization, known as entrainment, is primarily regulated by nocturnal light, which can be replicated in laboratory settings using a 15 min light pulse (LP) and by assessing locomotor activity. An LP during the early part of the dark phase delays the onset of locomotor activity, resulting in a phase delay, whereas an LP in the late dark phase advances activity onset, causing a phase advance. The clock gene Period 2 (Per2) plays a key role in this process. To investigate its contributions, we examined the effects of Per2 deletion in neurons versus astrocytes using glia-specific GPer2 (Per2/GfapCre) knockout (KO) and neuronal-specific NPer2KO (Per2/NesCre) mice. All groups were subjected to Aschoff type II protocol, where an LP was applied at ZT14 or ZT22 and the animals were released into constant darkness. As control, no LP was applied. Phase shift, period, amplitude, total activity count, and rhythm instability were assessed. Our findings revealed that mice lacking Per2 in neurons (NPer2) exhibited smaller phase delays and larger phase advances compared to control animals. In contrast, mice with Per2 deletion specifically in glial cells including astrocytes (GPer2) displayed normal clock resetting. Interestingly, the absence of Per2 in either of the cell types resulted in a shorter circadian period compared to control animals. These results suggest that astrocytic Per2 is important for maintaining the circadian period but is not required for phase adaptation to light stimuli. Full article

Light is a major environmental factor that regulates circadian rhythms and pineal melatonin synthesis. While the influence of nighttime light exposure on melatonin suppression has been extensively investigated, much less is known about the impact of photophase light wavelength on pineal function. The aim of the study was to determine the influence of monochromatic light during the photophase on diurnal changes in melatonin-related indoles in the rat pineal gland. Wistar rats were exposed for 7 days to 150 lx of monochromatic blue (463 ± 10 nm), green (523 ± 10 nm), or red (623 ± 10 nm) LED light, or to white fluorescent light (control), under a 12:12 light–dark cycle. Pineal glands were collected every 3 h over 24 h, and the indole content was analyzed by high-performance liquid chromatography. The results demonstrated that both the timing and course of N-acetylserotonin (NAS) and melatonin (MLT) rhythms were significantly affected by light wavelength. Blue light most effectively preserved the normal rhythmicity observed under full-spectrum white light, whereas green—and particularly red light—delayed nocturnal NAS and MLT synthesis. These changes were accompanied by concurrent alternations in rhythms of serotonin, its precursors, and metabolites. The data strongly suggest that spectral light composition during the photophase influences pineal indole metabolism via melanopsin-mediated phototransduction and possibly other retinal mechanisms. These findings may have implications for the design of artificial lighting environments in human life and animal housing. Full article

Alien Ponto-Caspian mysids Paramysis lacustris, Limnomysis benedeni and Hemimysis anomala were introduced into Lithuanian waters from Ukraine’s water reservoirs in the early 1960s. Their expansion from the primary introduction site in the Kaunas Reservoir, located on the Nemunas River, proceeded through secondary introductions and natural dispersal. The two species, P. lacustris and L. benedeni, are currently quite widespread in Lithuanian waters, whereas H. anomala has been observed exclusively in the Kaunas Reservoir until recently. Here, we present data from the most recent comprehensive survey of Ponto Caspian mysids and analyze the impact of sampling method on the likelihood of species detection. The results clearly indicate that the detection of larger-sized, more mobile species with good swimming abilities, such as P. lacustris, requires, in addition to conventional macroinvertebrate sampling, the use of devices designed to capture active nektobenthic animals. For this purpose, an epibenthic dredge or sledge is recommended. In contrast, the detection probability of the smaller-sized L. benedeni was not affected by the sampling method. The recent detection of the bloody-red mysid H. anomala near the Nemunas Delta suggests it may now be well-established in the area. However, due to its nocturnal lifestyle, the effective detection of this mysid requires dusk or nighttime sampling using equipment appropriate for capturing nektobenthic fauna. Full article

The brown kiwi (Apteryx mantelli) is a flightless, nocturnal bird native to New Zealand and is classified as “At Risk” due to predation from domestic dogs and ferrets. In the U.S., brown kiwi have been managed under the AZA Animal Population Management and Studbook Program since 2006, with the Smithsonian National Zoological Park (NZP) and Conservation Biology Institute (SCBI) maintaining the species since 1968. However, because they are nocturnal, kiwi are not good exhibit animals and often are difficult for zoo visitors to observe during the day. To address this, the NZP launched a “Meet-A-Kiwi” ambassador program in 1989 to engage the public and raise awareness. The program ran successfully for 28 years until 2017, when renovations closed the Bird House at the zoo in Washington, DC, and the birds were moved to the Front Royal, VA campus. Over time, concerns about the suitability of kiwi as ambassador birds arose as they are nocturnal and do not imprint on people. This study assessed the effects of outreach events, housing, and relocation on adrenal activity in five kiwi (four males, one female) by measuring fecal glucocorticoid metabolite (fGCM) concentrations, a physiological stress indicator, from March to October 2016. Two males participated in outreach (ambassadors), while two males and one female did not (controls). The results showed no significant differences in fGCM concentrations between ambassador and control birds, suggesting that outreach did not cause undue stress. However, individual factors (age, sex, hatching type, and display status) were associated with differences in fGCM concentrations, highlighting the need for personalized management. Further longitudinal studies are needed to explore the physiological responses of kiwi to captive conditions. Full article

Metabolic bone disease (MBD) is clinically characterized by bone deformities and is associated with vitamin D3 deficiency in diurnal animals. However, the pathogenesis and etiology of this condition in flying foxes, considered nocturnal animals, are poorly understood. Therefore, we conducted a survey aimed at various zoological parks housing flying foxes to elucidate the pathogenesis and etiology of MBD in these animals. Our results indicate that vitamin D3 may play a role in preventing metabolic bone disease in flying foxes due to its involvement in calcium absorption. However, these nocturnal animals seem to obtain vitamin D3 primarily through dietary sources in contrast to the cutaneous absorption described in diurnal species. Additionally, our results suggest that an appropriate diet for this species, including fruits, green vegetables, and other protein sources such as animal products and mineral supplementation, could contribute to preventing metabolic bone disease. Full article

The Central European fauna, in the last decades, has been undergoing a strong transformation due to four main factors: the retreat of living organisms that require cool and wet habitats, the proliferation of organisms that thrive in warm and dry conditions, the northward migration of Mediterranean organisms, and the gradual establishment of plants and animals with tropical origins. In this study, we detail the changes in the orders Diptera, Hymenoptera, and Lepidoptera and analyze the establishment of non native insects and the northward migration of Mediterranean insect species. The transformation towards a Mediterranean-type fauna is prominently indicated by the population in total abundance increase of xerothermic Aculeata, bee flies (Bombyliidae), and horse flies (Tabanidae). Additionally, groups that require cool and wet ecological conditions, particularly hoverflies (Syrphidae), but also sawflies (Tenthredinidae) and tachinid flies (Tachinidae), have shown a notable decline. In nocturnal moths, we observe a decrease in species richness in certain areas, as well as frequent outbreaks in populations of some less climate-sensitive species. Some species of butterflies are less sensitive to the current extent of climate change, exhibiting significant population in total abundance growth under protected conditions. However, most of the previously sporadic and rare butterfly species have proven to be climate-sensitive, unable to achieve significant population in abundance growth even under strict nature conservation. In recent decades, the influx from Mediterranean regions and the establishment of tropical non native insect species have turned at an exponential rate. We have reviewed the presence of alien insect species, recording 803 alien insect species in our region; 298 of them have arrived in the past quarter-century, with a significant proportion (54%) originating from tropical and Mediterranean regions. Full article

The biodiversity of invertebrate animals is largely affected by climatic changes. This study evaluates the seasonal abundance and diversity of non-insect arthropods in the King Abdulaziz Royal Reserve (KARR), Saudi Arabia, over four collection periods (summer, autumn, winter, and spring) during 2023. Sampling was conducted across multiple sites in the reserve using both active (manual collection and active surveying for the diurnal species) and passive (pitfall traps and malaise traps for the nocturnal species) methods. A total of 586 non-insect arthropod specimens were collected, representing four classes: Arachnida, Chilopoda, Branchiopoda, and Malacostraca. The results show that the most abundant species was the jumping spider Plexippus paykulli, which dominated collections across two seasons, with a peak abundance of 50.7% in late summer. Seasonal variations in non-insect arthropod diversity were observed, with a lower diversity recorded during January–March (4 species, and this may be attributed to this period revealing the lowest temperature reading recorded during the study period) and higher diversity in August–September (end of summer) and October–November (mid of autumn), with 14 species. Scorpions, particularly species from the families Buthidae and Scorpionidae, were common during the summer months, while solifuges and centipedes showed sporadic occurrences across seasons. These findings align with the results for arthropod distribution in arid regions, with temperature and resource availability as key drivers of biodiversity in desert environments because of their direct effects on the biochemical processes of these creatures. This study contributes valuable baseline data on the non-insect arthropod fauna of the KARR. The insights gained from this study can aid in conservation efforts and provide a foundation for further research on non-insect arthropod ecology in arid landscapes. Full article

Diurnal and nocturnal mammals have evolved unique behavioral and physiological adaptations to optimize survival for their day- or night-active lifestyle. The mechanisms underlying the opposite activity patterns are not fully understood but likely involve the interplay between the circadian time-keeping system and various arousal- or sleep-promoting factors, e.g., light or melatonin. Although the circadian systems between the two chronotypes share considerable similarities, the phase relationships between the principal and subordinate oscillators are chronotype-specific. While light promotes arousal and wakefulness in diurnal species like us, it induces sleep in nocturnal ones. Similarly, melatonin, the hormone of darkness, is commonly used as a hypnotic in humans but is secreted in the active phase of nocturnal animals. Thus, the difference between the two chronotypes is more complex than a simple reversal, as the physiological and neurological processes in diurnal mammals during the day are not equivalent to that of nocturnal ones at night. Such chronotype differences could present a significant translational gap when applying research findings obtained from nocturnal rodents to diurnal humans. The potential advantages of diurnal models are being discussed in a few sleep-related conditions including familial natural short sleep (FNSS), obstructive sleep apnea (OSA), and Smith–Magenis syndrome (SMS). Considering the difference in chronotype, a diurnal model will be more adequate for revealing the physiology and physiopathology pertaining to human health and disease, especially in conditions in which circadian rhythm disruption, altered photic response, or melatonin secretion is involved. We hope the recent advances in gene editing in diurnal rodents will promote greater utility of the diurnal models in basic and translational research. Full article

In agrarian systems where animal mobility is crucial for feed management, nutrient cycles and household economy, there is a notable lack of precise data on livestock mobility and herding practices. We introduce a methodology leveraging GPS-based behavioural models to analyse and document pastoral mobility in the Sahel. Over 2.5 years, we conducted a continuous collection of GPS data from transhumant and resident cattle herds in the Senegalese agropastoral semiarid rangelands. We developed a Hidden Markov Model robustly fitted to these data to classify recordings into three states of activity: resting (47% overall), foraging (37%) and travelling (16%). We detail our process for selecting the states and testing data subsets to guide future similar endeavours. The model describes state changes and how temperature affects them. By combining the resulting dataset with satellite-based land-use data, we show the distribution of activities across landscapes and seasons and within a day. We accurately reproduced key aspects of cattle mobility and characterised rarely documented features of Sahel agropastoral practices, such as transhumance phases, nocturnal grazing and in-field rainy season paddocking. These results suggest that our methodology, which we make available, could be valuable in addressing issues related to the future of Sahelian pastoralism. Full article

Significant research investment into tropical rock lobster (TRL) aquaculture production methods has led to a rapidly developing industry in Vietnam and, more recently, in Australia. The need for an effective formulated feed has been highlighted for both industries; however, feed intake has been a consistent limitation. Visual and chemical cues regulating feed recognition and consumption are expected to yield valuable data, leading to increased feed intake. Lobsters were placed in white- and grey-coloured enclosures to examine the effect of background colour on their feeding behaviour in terms of feeding occurrence and response time. The impact of background colour on TRL feeding behaviour found no statistically significant differences between TRL in white and grey enclosures, suggesting grayscale contrast does not directly affect feeding behaviour. Experiment 2 studied the effects of coloured feeding zones on feeding response in white enclosures. Yellow feeding zones led to a decreased feeding time (473 ± 443 s) and increased time spent feeding (168 ± 1832 s) compared to other colours, possibly due to the yellow-blue chromaticity (b*) contrast. Experiment 3 examined chemo-attractants (glycine, taurine and inositol) and their influence on the feeding behaviour of TRL, but no increased responses were observed. Experiments two and three assessed TRL feeding activity in morning and evening periods, highlighting their nocturnal behaviour, with more feeding occurring in the evening. This project enhances our understanding of photoreceptive and chemoreceptive factors affecting TRL feeding behaviour with formulated feed. It also reveals the potential for background colour changes to enhance marketable colours in commercial settings. Additionally, the study confirmed the effective use of animal tracking software (EthoVision XT) for lobster species tracking in future behavioural trials. Full article

In wildlife rehabilitation centers, thousands of animals are treated annually, with a substantial proportion being birds of prey. Since vision is essential for the survival of these species, this study focused on investigating the causes of ocular injuries in raptors admitted to four rehabilitation centers across mainland Portugal from 2017 to 2021. Of the 2207 birds admitted during this period, 156 (7%) presented ocular injuries. Hyphema (28.2%) and corneal ulcers (20.5%) were the most prevalent injuries, often occurring together or alongside lens luxation. Nocturnal raptors showed a higher prevalence of these injuries (76.9%) compared to diurnal raptors (23.1%). A significant association was found between ocular injuries and causes of admission, particularly with ocular hemorrhages and multiple injuries in the eye. Despite the severity of the ocular injuries, the release rate remained relatively high at 51%, underscoring the critical role of comprehensive ocular examinations and vision assessments in guiding treatment decisions and discharge decisions. This study highlights the need for further research with larger samples to better understand the impact of ocular injuries on the rehabilitation success of wild birds in Portugal. Full article

This paper addresses the potential for technology to support husbandry and enrichment opportunities that enhance the welfare of zoo and sanctuary-housed nocturnal and crepuscular species. This topic was investigated through the medium of a multidisciplinary workshop (Moon Jam) that brought together species experts, zoo designers, Animal-Computer Interaction researchers and post-graduate students in collaborative discussions and design sessions. We explain the context through an examination of existing research and current practices, and report on specific challenges raised and addressed during the Moon Jam, highlighting and discussing key themes that emerged. Finally, we offer a set of guidelines to support the integration of technology into the design of animal husbandry and enrichment that support wellbeing, to advance the best practices in keeping and managing nocturnal and crepuscular animals. Full article

Background: Some epidemiological studies suggest that early exposure to animal allergens during infancy reduces the risk of bronchial asthma in school-age children. However, the observed associations in some cases may be an effect of the study used (epidemiological observational studies, especially a cross-sectional study) and indicate reverse causality. Aim: This study aimed to determine the association between exposure to animal allergens and the prevalence of respiratory diseases, including bronchial asthma, considering the potential impact of reverse causality on the observed relationships. Material and methods: An analysis of data from a cross-sectional epidemiological study conducted in 2020 involving 3237 primary school students aged 7–15 years in the Silesian Province (Southern Poland) was carried out. The parents of students completed a questionnaire based on The International Study on Asthma and Allergies in Childhood (ISAAC). The relationship between the occurrence of chronic cough, wheezing, and dyspnea in the last 12 months, night waking due to dyspnea, and asthma in the presence of pets was assessed. Exposure to animal allergens was determined by answering the question, “Are there any furry or feathered animals in the home?” with three response options: “yes; they have been in the past; no” (Scenario 1). For the analyses and to reveal a potential reverse causality effect, the last two response categories regarding pet ownership were combined to form a “no” category in Scenario 2, and the first two answers were combined into a “yes” category in Scenario 3. A chi-square test was used to assess the relationship between variables, and a statistical significance level of p < 0.05 was adopted. Results: Chronic cough affected 9.5% of children, wheezing in the last 12 months—9.2%, night waking due to dyspnea—5.8%, dyspnea in the last 12 months—4.8%, bronchial asthma—9.2%. Analysis considering the category of having or not having pets (yes vs. no) showed that bronchial asthma was statistically significantly more common in children who did not have pets at home (10.9% vs. 7.9%, p = 0.002). A similar situation was observed for wheezing in the past 12 months (10.7% vs. 8.1%; p = 0.01) and nocturnal awakening due to dyspnea (6.8% vs. 5.1%, p = 0.03). No statistically significant differences were observed for the other symptoms. Analysis by time of pet ownership (a. present; b. present but in the past; c. not present) highlighted similar relationships. Asthma (a. 7.7% vs. b. 13.4% vs. c. 7.7%; p = 0.004), wheezing in the past 12 months (a. 8.1% vs. b. 8.9% vs. c. 10.9%, p = 0.03) and night waking (a. 5.0% vs. b. 4.5% vs. c. 7.1%; p = 0.04) were more common in children without pets and those who had owned pets in the past. The highest proportion of children with asthma was in homes where pets were present in the past. Conclusions: Analyses indicating a relationship between a higher prevalence of asthma and some respiratory symptoms, and the absence of pets cannot be considered as a casual association. The analysis conducted did not reveal a reverse causality effect. The results of observational epidemiological studies, especially a cross-sectional study, should always be interpreted with caution, considering possible distortions and conclusions drawn. Full article

Melatonin, an endogenous indolamine derived from tryptophan, is primarily synthesized by the pineal gland in mammals and regulated by a complex neural system. Its release follows a circadian rhythm, which is crucial for regulating physiological processes in response to light–dark cycles in both humans and animals. In this review, we report that the presence of this hormone in bovine milk, with significant differences in concentration between daytime and nighttime milking, has increased interest in milk as a natural source of bioactive molecules. Melatonin lowers cortisol levels at night, reduces body temperature and blood pressure, coinciding with decreased alertness and performance, acts as an antioxidant and anti-inflammatory agent, modulates the immune system, offers neuroprotective benefits, and supports gastrointestinal health by scavenging free radicals and reducing oxidative stress in dairy cows. Many factors influence the release of melatonin, such as the intensity of artificial lighting during nighttime milking, the frequency of milkings, milk yield, and genetic differences between animals. Nocturnal milking under low-intensity light boosts melatonin, potentially reducing oxidative damage and mastitis risk. Additionally, ultra-high temperature (UHT) treatment does not significantly affect the melatonin content in milk. However, further research on its stability during milk processing and storage is crucial for ensuring product efficacy. In some countries, nighttime milk with naturally elevated melatonin content is already commercialized as a natural aid for sleep. Thus, naturally melatonin-rich milk may be a promising alternative to synthetic supplements for promoting better sleep and overall well-being. Full article

Population abundance and density estimates play important roles in biodiversity conservation assessment and can lead to prioritization of conservation efforts, strategies, and management. The Calabar angwantibo (Arctocebus calabarensis) is a poorly studied, Near-Threatened nocturnal, arboreal mammal species occurring only in the lowland moist tropical rainforest blocks of southeastern Nigeria and southwestern Cameroon. Like other arboreal nocturnal mammals, there are gaps in knowledge of the distribution and abundance of this species, which may be facing population declines due to habitat loss and hunting. In this study, we investigated the abundance and density of A. calabarensis in the Oban Hills Region of Nigeria. We conducted systematic distance sampling survey along 32 transects in different habitats in a 1227 km of survey efforts. A total of 41 sightings of A. calabarensis were detected, resulting in an abundance of 7345 individuals (95% CI = 1.51–4.37) with an estimated density of 2.57 animals/km². The estimated population abundance is 6515 individuals in closed-canopy forests and 830 individuals in secondary forests, with encounter rates of 0.52 individual/km² and 0.60 individuals/km² in the closed canopy and secondary forest habitats. The global estimates encounter rate of A. calabarensis across the habitat types is 0.33 individuals/km² and population abundance of 4456 individuals. Our findings indicate that the A. calabarensis populations can adapt to low changes in forest habitat modifications resulting from increasing and widespread forest disturbance by human-dominated activity, which is giving way to forest clearance for agriculture cultivation and infrastructural development. Our findings help to fill a knowledge gap regarding this species and may help establish a baseline for future management, population monitoring, and conservation of the cryptic population of A. calabarensis in Cross-Sanaga Forests. Full article