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1
Vredevoe, L. K., R. B. Kimsey, and P. J. Richter. "Temporal drop-off pattern of juvenile Ixodes pacificus (Acari: Ixodidae)." Canadian Journal of Zoology 75, no. 4 (1997): 613–17. http://dx.doi.org/10.1139/z97-076.
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We determined the temporal drop-off pattern of juvenile western black-legged ticks, Ixodes pacificus Cooley and Kohls, by recording the time of day that replete ticks dropped off common laboratory-reared and field-caught rodents. The majority of subadult ticks dropped during daylight hours. Larvae that attached to nocturnally active murid or diurnal sciurid rodents left their hosts during slightly different periods of the day. Larvae primarily departed from murids between 14:00 and 18:00 and from sciurids between 10:00 and 14:00. Drop-off of nymphs from rodents was significantly greater between 14:00 and 18:00 than between 18:00 and 06:00, although nymphs tended to leave BALB/c white mice earlier in the day. Because subadult ticks leave diurnally or nocturnally active hosts at the same time of day, drop-off appears to be independent of the temporal patterns of host activity. Diurnal drop-off will result in engorged ticks remaining in the nests of nocturnal hosts but dropping to the ground from diurnal hosts. Thus, we propose that temporal patterns of host activity mediate the spatial distribution of I. pacificus.
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Hall, Margaret I., Jason M. Kamilar, and E. Christopher Kirk. "Eye shape and the nocturnal bottleneck of mammals." Proceedings of the Royal Society B: Biological Sciences 279, no. 1749 (2012): 4962–68. http://dx.doi.org/10.1098/rspb.2012.2258.
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Most vertebrate groups exhibit eye shapes that vary predictably with activity pattern. Nocturnal vertebrates typically have large corneas relative to eye size as an adaptation for increased visual sensitivity. Conversely, diurnal vertebrates generally demonstrate smaller corneas relative to eye size as an adaptation for increased visual acuity. By contrast, several studies have concluded that many mammals exhibit typical nocturnal eye shapes, regardless of activity pattern. However, a recent study has argued that new statistical methods allow eye shape to accurately predict activity patterns of mammals, including cathemeral species (animals that are equally likely to be awake and active at any time of day or night). Here, we conduct a detailed analysis of eye shape and activity pattern in mammals, using a broad comparative sample of 266 species. We find that the eye shapes of cathemeral mammals completely overlap with nocturnal and diurnal species. Additionally, most diurnal and cathemeral mammals have eye shapes that are most similar to those of nocturnal birds and lizards. The only mammalian clade that diverges from this pattern is anthropoids, which have convergently evolved eye shapes similar to those of diurnal birds and lizards. Our results provide additional evidence for a nocturnal ‘bottleneck’ in the early evolution of crown mammals.
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Hall, Margaret I., Jason M. Kamilar, and E. Christopher Kirk. "Eye shape and the nocturnal bottleneck of mammals." Proceedings of the Royal Society B: Biological Sciences 279, no. 1749 (2012): 4962–68. https://doi.org/10.5281/zenodo.13485899.
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(Uploaded by Plazi for the Bat Literature Project) Most vertebrate groups exhibit eye shapes that vary predictably with activity pattern. Nocturnal vertebrates typically have large corneas relative to eye size as an adaptation for increased visual sensitivity. Conversely, diurnal vertebrates generally demonstrate smaller corneas relative to eye size as an adaptation for increased visual acuity. By contrast, several studies have concluded that many mammals exhibit typical nocturnal eye shapes, regardless of activity pattern. However, a recent study has argued that new statistical methods allow eye shape to accurately predict activity patterns of mammals, including cathemeral species (animals that are equally likely to be awake and active at any time of day or night). Here, we conduct a detailed analysis of eye shape and activity pattern in mammals, using a broad comparative sample of 266 species. We find that the eye shapes of cathemeral mammals completely overlap with nocturnal and diurnal species. Additionally, most diurnal and cathemeral mammals have eye shapes that are most similar to those of nocturnal birds and lizards. The only mammalian clade that diverges from this pattern is anthropoids, which have convergently evolved eye shapes similar to those of diurnal birds and lizards. Our results provide additional evidence for a nocturnal 'bottleneck' in the early evolution of crown mammals.
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Hall, Margaret I., Jason M. Kamilar, and E. Christopher Kirk. "Eye shape and the nocturnal bottleneck of mammals." Proceedings of the Royal Society B: Biological Sciences 279, no. 1749 (2012): 4962–68. https://doi.org/10.5281/zenodo.13485899.
Full textAbstract:
(Uploaded by Plazi for the Bat Literature Project) Most vertebrate groups exhibit eye shapes that vary predictably with activity pattern. Nocturnal vertebrates typically have large corneas relative to eye size as an adaptation for increased visual sensitivity. Conversely, diurnal vertebrates generally demonstrate smaller corneas relative to eye size as an adaptation for increased visual acuity. By contrast, several studies have concluded that many mammals exhibit typical nocturnal eye shapes, regardless of activity pattern. However, a recent study has argued that new statistical methods allow eye shape to accurately predict activity patterns of mammals, including cathemeral species (animals that are equally likely to be awake and active at any time of day or night). Here, we conduct a detailed analysis of eye shape and activity pattern in mammals, using a broad comparative sample of 266 species. We find that the eye shapes of cathemeral mammals completely overlap with nocturnal and diurnal species. Additionally, most diurnal and cathemeral mammals have eye shapes that are most similar to those of nocturnal birds and lizards. The only mammalian clade that diverges from this pattern is anthropoids, which have convergently evolved eye shapes similar to those of diurnal birds and lizards. Our results provide additional evidence for a nocturnal 'bottleneck' in the early evolution of crown mammals.
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Hall, Margaret I., Jason M. Kamilar, and E. Christopher Kirk. "Eye shape and the nocturnal bottleneck of mammals." Proceedings of the Royal Society B: Biological Sciences 279, no. 1749 (2012): 4962–68. https://doi.org/10.5281/zenodo.13485899.
Full textAbstract:
(Uploaded by Plazi for the Bat Literature Project) Most vertebrate groups exhibit eye shapes that vary predictably with activity pattern. Nocturnal vertebrates typically have large corneas relative to eye size as an adaptation for increased visual sensitivity. Conversely, diurnal vertebrates generally demonstrate smaller corneas relative to eye size as an adaptation for increased visual acuity. By contrast, several studies have concluded that many mammals exhibit typical nocturnal eye shapes, regardless of activity pattern. However, a recent study has argued that new statistical methods allow eye shape to accurately predict activity patterns of mammals, including cathemeral species (animals that are equally likely to be awake and active at any time of day or night). Here, we conduct a detailed analysis of eye shape and activity pattern in mammals, using a broad comparative sample of 266 species. We find that the eye shapes of cathemeral mammals completely overlap with nocturnal and diurnal species. Additionally, most diurnal and cathemeral mammals have eye shapes that are most similar to those of nocturnal birds and lizards. The only mammalian clade that diverges from this pattern is anthropoids, which have convergently evolved eye shapes similar to those of diurnal birds and lizards. Our results provide additional evidence for a nocturnal 'bottleneck' in the early evolution of crown mammals.
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Hall, Margaret I., Jason M. Kamilar, and E. Christopher Kirk. "Eye shape and the nocturnal bottleneck of mammals." Proceedings of the Royal Society B: Biological Sciences 279, no. 1749 (2012): 4962–68. https://doi.org/10.5281/zenodo.13485899.
Full textAbstract:
(Uploaded by Plazi for the Bat Literature Project) Most vertebrate groups exhibit eye shapes that vary predictably with activity pattern. Nocturnal vertebrates typically have large corneas relative to eye size as an adaptation for increased visual sensitivity. Conversely, diurnal vertebrates generally demonstrate smaller corneas relative to eye size as an adaptation for increased visual acuity. By contrast, several studies have concluded that many mammals exhibit typical nocturnal eye shapes, regardless of activity pattern. However, a recent study has argued that new statistical methods allow eye shape to accurately predict activity patterns of mammals, including cathemeral species (animals that are equally likely to be awake and active at any time of day or night). Here, we conduct a detailed analysis of eye shape and activity pattern in mammals, using a broad comparative sample of 266 species. We find that the eye shapes of cathemeral mammals completely overlap with nocturnal and diurnal species. Additionally, most diurnal and cathemeral mammals have eye shapes that are most similar to those of nocturnal birds and lizards. The only mammalian clade that diverges from this pattern is anthropoids, which have convergently evolved eye shapes similar to those of diurnal birds and lizards. Our results provide additional evidence for a nocturnal 'bottleneck' in the early evolution of crown mammals.
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Ejigu, Dessalegn, Afework Bekele, and Larkin Powell. "Diurnal activity patterns of walia ibex (Capra walie) in Simien Mountains National Park, Ethiopia." Journal of Biology and Life Science 11, no. 2 (2020): 83. http://dx.doi.org/10.5296/jbls.v11i2.17049.
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Walia ibex (Capra walie) is an endangered and endemic species restricted to Simien Mountains National Park (SMNP), Ethiopia. Data on activity patterns of walia ibex were collected during October 2009 to November 2011, and the main objective of the research was to determine diurnal activity patterns of walia ibex in Simien Mountains National Park in order to design sound conservation strategies for the species. Scan sampling method was used for data collection on diurnal activity patterns of walia ibex. Diurnal activity patterns in walia ibex were bimodal, in which they were active before and after noon. They rest in shade on rocks and cliffs during the mid-day to protect themselves from hot sun and predators. Activity patterns of walia ibex during the day showed statistically significant differences (F7,18228= 82.09, df=7, p<0.01). Feeding showed significant differences compared to moving, standing, resting, socializing, and other activities (p<0.05). Diurnal activity records in the walia ibex population during the wet and the dry seasons showed that time spent feeding was the highest and vigilance was the lowest. Knowledge of the pattern of this behavior can especially be useful to design conservation planning as successful reproduction in the population may be threatened by anthropogenic disturbances. Thus, information about the diurnal activity patterns of walia ibex is essential for conservation planning of the endemic and endangered walia ibex in its natural habitats.
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Ramos, Déborah, Lucian Canto, Felipe Silva, Martín Montes, João Pedro Souza-Alves, and Lucas Gonçalves. "Activity patterns of domestic dogs and native terrestrial mammals in the Tapacurá Ecological Station, Brazil." Mammalogy Notes 10, no. 1 (2024): 359. http://dx.doi.org/10.47603/mano.v10n1.359.
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Domestic dogs are a threat to biodiversity. We evaluated the activity patterns of domestic dogs and terrestrial mammals in a patch of Atlantic forest in northeastern Brazil. We expected native mammals to change their temporal pattern of activity in the presence of domestic dogs. We installed 16 camera traps in 2019 (January-March) and 16 cameras in 2021 (February-April), with a total effort effort of 640 trap days. We classified the activity of the species as diurnal, cathemeral, nocturnal and crepuscular. We found 274 records of 11 mammal species and overlapping activity between domestic dogs and terrestrial mammals. Coatis and agoutis were strictly diurnal in both years, while domestic dogs presented a catemanal activity pattern in 2021. Aguties and domestic dogs presented a uniform pattern, but coatis did not. Although our findings suggest a limited influence of domestic dogs on terrestrial mammals, vaccination or sterilization programs should be implemented to avoid an increase in the negative impact of dogs on native fauna.
9
Brown, Scott A., Kimberly Langford, and Stacy Tarver. "Effects of certain vasoactive agents on the long-term pattern of blood pressure, heart rate, and motor activity in cats." American Journal of Veterinary Research 58, no. 6 (1997): 647–52. http://dx.doi.org/10.2460/ajvr.1997.58.06.647.
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Abstract Objective To determine whether a diurnal pattern exists in cardiovascular variables and motor activity, and whether pharmacologic agents that decrease (angiotensin converting enzyme inhibitor) or increase (Nω-nitro-L-arginine methyl ester [L-NAME]) blood pressure alter the pattern. Animals 6 clinically normal cats. Procedure Radiotelemetric implants were used to measure systemic arterial pressure, heart rate, and motor activity in conscious cats maintained in cages. Measurements were obtained during absence of treatment (control), treatment with dietary salt restriction plus an inhibitor of angiotensin converting enzyme (2.5 mg of lisinopril, PO, daily) and treatment with an inhibitor of nitric oxide production (0.1% L-NAME in the drinking water). Results A diurnal pattern in arterial pressure and motor activity was observed, with highest values obtained during presence of laboratory personnel. Mean values for arterial pressure obtained during light hours varied from those obtained during darkness (P < 0.05), but by < 3 mm of Hg. Dietary sodium restriction did not have an appreciable effect on arterial pressure, but the combined administration of a low sodium diet plus lisinopril decreased (P < 0.05) measured indices of arterial pressure. Administration of L-NAME increased arterial pressure (P < 0.05) and altered its diurnal pattern. Conclusions Although a diurnal pattern of arterial pressure was observed, variations were mostly associated with presence of human beings. Administration of L-NAME, but not lisinopril, altered this diurnal pattern. Clinical Relevance Factors that modify arterial pressure may alter the diurnal pattern of cardiovascular variables. In measuring arterial pressure in cats, the effects of human contact may artifactually increase such variables. (Am J Vet Res 1997;58:647–652)
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Logendra, Sitheswary, and Harry W. Janes. "DIURNAL PATTERN OF ADP-GLUCOSE PYROPHOSPHORYLASE ACTIVITY IN TOMATO." HortScience 28, no. 5 (1993): 537g—537. http://dx.doi.org/10.21273/hortsci.28.5.537g.
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The diurnal pattern of the activity of the starch synthesízing enzyme ADP-glucose Pyrophosphorylase was studied in young tomato seedlings, grown under a light/dark cycle of 12h/12h. The third leaf from the base of the plant was used for the study when they were 80 to 90% fully expanded. The enzyme activity had two peaks, a smaller peak during the light period and a larger peak during the dark period. The activity began to increase before the lights were turned on and it was maintained for the first four hours of the light period and then began to decline. Similarly, the activity began to increase again before the lights were turned off and remained high for the first four hours of the dark period.
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Gartstein, Maria A., Erich Seamon, Stephanie F. Thompson, and Liliana J. Lengua. "Featured Article: Community Crime Exposure and Risk for Obesity in Preschool Children: Moderation by the Hypothalamic–Pituitary–Adrenal-Axis Response." Journal of Pediatric Psychology 43, no. 4 (2017): 353–65. http://dx.doi.org/10.1093/jpepsy/jsx116.
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Abstract Objective Identification of early risk factors related to obesity is critical to preventative public health efforts. In this study, we investigated links between the Hypothalamic–Pituitary–Adrenal (HPA)-axis activity (diurnal cortisol pattern), geospatially operationalized exposure to neighborhood crime, and body mass index (BMI) for a sample of 5-year-old children. Greater community crime exposure and lower HPA-axis activity were hypothesized to contribute to higher BMI, with child HPA-axis moderating the association between crime exposure and BMI. Method Families residing within the boundaries of the City of Seattle (N = 114) provided information concerning demographic/psychosocial risk factors, used to calculate a Cumulative Risk Index, indicating the number of contextual adversities present. Child BMI and diurnal cortisol pattern (derived from assays of saliva samples) were examined, along with neighborhood crime indices computed with publically available information, based on participants’ locations. Results Hierarchical multiple regression analyses, adjusted for covariates (cumulative risk, age, and sex), indicated that crime proximity made a unique contribution to child BMI, in the direction signaling an increase in the risk for obesity. Consistent with our hypothesis, a significant interaction was observed, indicative of moderation by diurnal cortisol pattern. Follow-up simple slope analyses demonstrated that crime exposure was significantly related to higher BMI for children with low-flat (blunted) diurnal cortisol patterns, where community crime and BMI were not significantly associated at higher levels of cortisol. Conclusion Community crime exposure contributes to higher BMI as early as the preschool period, and blunted diurnal cortisol patterns may place children experiencing neighborhood adversity at greater risk for obesity.
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Steen, Ronny. "Diel activity patterns of urban Woodchucks (Marmota monax) revealed by camera traps at burrows in southwestern Ontario, Canada." Canadian Field-Naturalist 134, no. 4 (2021): 353–60. http://dx.doi.org/10.22621/cfn.v134i4.2110.
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Animals display a range of diurnal and nocturnal activity patterns and, among mammals, a high proportion of species are crepuscular or nocturnal. Daily activities are often endogenous and oscillate on a light:dark regime. Such cycles are referred to as ‘circadian’ and are generally influenced by biotic and abiotic factors. I investigated the daily activity of urban Woodchucks (Marmota monax) by using 24-hour camera traps at backyard burrows in London, Ontario, Canada, in June. Cameras enabled the collection of data that would otherwise have been labour intensive by direct observation. Statistical modelling showed that Woodchucks exhibited a strictly diurnal activity pattern. The unimodal activity pattern started at sunrise and ended before sunset. The general daily activity trend was similar to the pattern described by others who used direct observations and telemetry to monitor Woodchucks in more rural settings. Temperature and wind were not included in the best-fit model. Camera trapping is a non-invasive method that could give insight to diel activity as it can easily monitor extended periods and reduce the effort required by direct observation.
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Arrese, C., and PB Runham. "Redefining the activity pattern of the honey possum (Tarsipes rostratus)." Australian Mammalogy 23, no. 2 (2001): 169. http://dx.doi.org/10.1071/am01169.
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ANIMALS are commonly separated into two major categories based on their activity patterns: diurnal and nocturnal. However, evidence of numerous species exhibiting diverse periods of activity, including arhythmic and crepuscular habits, broadens the description. The honey possum (Tarsipes rostratus), a small West-Australian marsupial feeding exclusively on nectar and pollen, has been described as strongly nocturnal (Wooller et al. 1981; Russell and Renfree 1989). However, infrequent daytime activity in captivity (Russell 1986) and in the wild under cold, cloudy conditions, has been reported (Hopper and Burbidge 1982; du Plessis and du Plessis 1995). During trapping exercises in the region of Jurien Bay (250 km north of Perth, Western Australia), several animals were observed foraging after sunrise and before sunset, with occasional diurnal activity. To date, no study has investigated directly the activity periods of the species. Furthermore, studies of the visual capabilities of T. rostratus revealed that its retinal organisation is not compatible with a nocturnal lifestyle, but presents features comparable to those found in diurnal species (Arrese 2002; Arrese et al. 2002). Such discrepancies warranted the monitoring of activity periods (rhythmicity) of T. rostratus in its natural environment, a study reported here. We discuss our results in the context of the visual ecology of the species.
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Frank, M. G., and H. C. Heller. "Development of diurnal organization of EEG slow-wave activity and slow-wave sleep in the rat." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 273, no. 2 (1997): R472—R478. http://dx.doi.org/10.1152/ajpregu.1997.273.2.r472.
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This study characterizes the development of diurnal patterns of slow-wave sleep (SWS) distribution and SWS electroencephalographic (EEG) delta-power (DP) density in 12- to 24-day-old rats (P12-P24). Diurnal organization in sleep-wake distribution was established by P20. A decline in SWS DP across the light phase did not appear until P24. Before P20, SWS DP increased across the light phase in a pattern inverse to that typically seen in adult rats. At P20, SWS DP was evenly distributed across the light phase, and at P24, SWS DP declined across the light phase. The transient dissociation between diurnal organization in sleep-wake cycles and SWS DP suggests that circadian and homeostatic sleep regulatory mechanisms develop at different rates in the postnatal period.
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Gattermann, Rolf, Robert E. Johnston, Nuri Yigit, et al. "Golden hamsters are nocturnal in captivity but diurnal in nature." Biology Letters 4, no. 3 (2008): 253–55. http://dx.doi.org/10.1098/rsbl.2008.0066.
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Daily activity rhythms are nearly universal among animals and their specific pattern is an adaptation of each species to its ecological niche. Owing to the extremely consistent nocturnal patterns of activity shown by golden hamsters ( Mesocricetus auratus ) in the laboratory, this species is a prime model for studying the mechanisms controlling circadian rhythms. In contrast to laboratory data, we discovered that female hamsters in the wild were almost exclusively diurnal. These results raise many questions about the ecological variables that shape the activity patterns in golden hamsters and the differences between laboratory and field results.
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Klante, Gabriela, Karin Secci, Mireille Masson-Pévet, et al. "Interstrain differences in activity pattern, pineal function, and SCN melatonin receptor density of rats." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 276, no. 4 (1999): R1078—R1086. http://dx.doi.org/10.1152/ajpregu.1999.276.4.r1078.
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We investigated the possibility that strain-dependent differences in the diurnal pattern of wheel running activity rhythms are also reflected in the melatonin profiles. The inbred rat strains ACI/Ztm, BH/Ztm, and LEW/Ztm. LEW were examined for diurnal [12:12-h light-dark (LD)] wheel running activity, urinary 6-sulphatoxymelatonin (aMT6s) excretion, melatonin concentrations of plasma and pineal glands, and melatonin receptor density in the suprachiasmatic nuclei (SCN). ACI rats displayed unimodal activity patterns with a high level of activity, whereas BH and LEW rats showed multimodal activity patterns with ultradian components and reduced activity levels. In contrast, the individual daily profiles of aMT6s excretion and mean melatonin synthesis followed a unimodal time pattern in all three strains, suggesting that different output pathways of the SCN are responsible for the temporal organization of locomotor activity and pineal melatonin synthesis. In addition, melatonin synthesis at night and SCN melatonin receptor density at day were significantly higher in BH and LEW rats than in ACI rats. These results support the hypothesis of a long-term stimulating effect of melatonin on its own receptor density in the SCN.
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Cid, Bruno, Luiz Gustavo R. Oliveira-Santos, and Guilherme Mourão. "The relationship between external temperature and daily activity in a large rodent (Dasyprocta azarae) in the Brazilian Pantanal." Journal of Tropical Ecology 31, no. 5 (2015): 469–72. http://dx.doi.org/10.1017/s0266467415000309.
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Abstract:Daily activity patterns reflect interactions between circadian mechanisms and environmental stimuli. Among these stimuli, temperature can be an important factor affecting activity budgets. To sample the agouti (Dasyprocta azarae), a systematic camera-trap grid was established with 50 independent sampling sites. A circular kernel function was used to characterize the activity patterns of the agouti population. To evaluate shifts in activity as a function of mean daily temperature, the entire set of records was subdivided into smaller sets covering different temperature ranges. The activity pattern belonging to each set was characterized and compared through the overlap of their full activity (95% isopleth) and activity core (50% isopleth). Based on 400 independent records, agoutis were predominately diurnal. They shifted their activity core, while keeping their activity range (the amount of time a population remains active during the 24-h cycle) constant through the temperature gradient. The agouti demonstrated a unimodal activity pattern at lower temperatures, which became more bimodal at higher temperatures. Nevertheless, it kept its activity range constant, regardless of temperature. These results likely reflect a trade-off between activity time and thermoregulation during the diurnal period and demonstrate how the agouti can change its behaviour to achieve thermal comfort.
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Pépin, Dominique, Christophe Abegg, and Cécile Richard. "Diurnal activity patterns within female herds of isard around parturition time." Canadian Journal of Zoology 69, no. 3 (1991): 776–82. http://dx.doi.org/10.1139/z91-112.
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We compared diurnal activity patterns of isards (Rupicapra pyrenaica) within female herds around the time of parturition in a Pyrenean reserve. From mid-April to mid-May, i.e., at the end of the gestation period, adult females spent significantly more time foraging (76 vs. 65%) and less time resting than yearlings did. From mid-June to mid-July, after the birth of kids, adult females and yearlings had exactly the same time budget (62% for foraging) and the same activity pattern, with a well-marked resting phase at midday. Analysis of data at 15-min intervals indicated synchronism in activity when animals leave the area by crossing the crest line, or when arriving at their foraging or resting phases. During the 2 first months of their life, kids had a polyphasic diurnal activity pattern characterized by four distinct foraging phases 4 h apart, and three peaks in resting activity between midday and evening. Nevertheless, some behavioural and physiological mechanisms permitted kids to synchronize their activity with that of other herd members.
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Ilan, M., and Y. Yom-Tov. "Diel Activity Pattern of a Diurnal Desert Rodent, Psammomys obesus." Journal of Mammalogy 71, no. 1 (1990): 66–69. http://dx.doi.org/10.2307/1381317.
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Challet, Etienne. "Minireview: Entrainment of the Suprachiasmatic Clockwork in Diurnal and Nocturnal Mammals." Endocrinology 148, no. 12 (2007): 5648–55. http://dx.doi.org/10.1210/en.2007-0804.
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Daily rhythmicity, including timing of wakefulness and hormone secretion, is mainly controlled by a master clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN clockwork involves various clock genes, with specific temporal patterns of expression that are similar in nocturnal and diurnal species (e.g. the clock gene Per1 in the SCN peaks at midday in both categories). Timing of sensitivity to light is roughly similar, during nighttime, in diurnal and nocturnal species. Molecular mechanisms of photic resetting are also comparable in both species categories. By contrast, in animals housed in constant light, exposure to darkness can reset the SCN clock, mostly during the resting period, i.e. at opposite circadian times between diurnal and nocturnal species. Nonphotic stimuli, such as scheduled voluntary exercise, food shortage, exogenous melatonin, or serotonergic receptor activation, are also capable of shifting the master clock and/or modulating photic synchronization. Comparison between day- and night-active species allows classifications of nonphotic cues in two, arousal-independent and arousal-dependent, families of factors. Arousal-independent factors, such as melatonin (always secreted during nighttime, independently of daily activity pattern) or γ-aminobutyric acid (GABA), have shifting effects at the same circadian times in both nocturnal and diurnal rodents. By contrast, arousal-dependent factors, such as serotonin (its cerebral levels follow activity pattern), induce phase shifts only during resting and have opposite modulating effects on photic resetting between diurnal and nocturnal species. Contrary to light and arousal-independent nonphotic cues, arousal-dependent nonphotic stimuli provide synchronizing feedback signals to the SCN clock in circadian antiphase between nocturnal and diurnal animals.
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Hoekstra, Tiny, Evert Schouten, Cornelis Kluft, and Johanna Geleijnse. "Diurnal Variation in PAI-1 Activity Predominantly Confined to the 4G-allele of the PAI-1 Gene." Thrombosis and Haemostasis 88, no. 11 (2002): 794–98. http://dx.doi.org/10.1055/s-0037-1613304.
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SummaryWe examined the diurnal pattern in Plasminogen Activator Inhibitor-type 1 (PAI-1) activity and Plasminogen activator (t-PA) in relation to the 4G/5G-polymorphism in the promoter of the PAI-1 gene. The analyses were performed in the Arnhem Elderly Study, a populationbased study of 598 elderly. A single blood sample was drawn and the time of blood sampling was recorded (between 8 a. m. and 5.30 p. m.). Plasma PAI-1 activity was strongly associated with time of blood sampling, showing the highest values in the early morning. The diurnal pattern was clearly present in the 4G/4G (n = 184) and 4G/5G (n = 275) genotypes, but not in the 5G/5G-genotype (n = 139). T-PA antigen showed a weak diurnal variation, which did not differ across the variants of the 4G/5G-polymorphism. Our findings raise the hypothesis that 5G-homozygotic persons may be relatively protected from diurnal variation in the occurrence of coronary events.
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Brännäs, Eva, and Anders Alanärä. "Is diel dualism in feeding activity influenced by competition between individuals?" Canadian Journal of Zoology 75, no. 5 (1997): 661–69. http://dx.doi.org/10.1139/z97-086.
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The feeding activity of eight groups of 15 rainbow trout (Oncorhynchus mykiss) each was recorded using self-feeders combined with passive integrated transponder (PIT) tag registrations. The diel pattern for all individuals was established by analysing the PIT-tag registrations. Most trout released the self-feeders during daylight, but in all groups some individuals (1–5) were active mainly during the night. The hypothesis that dualism in diel feeding activity is influenced by competition for food resources between individuals was then tested. In the first round, the diurnally active group members were removed, leaving groups with only 5 mainly nocturnally active individuals. After 3 weeks, the nocturnal individuals still released the self-feeders mainly in darkness. In a second round, the nocturnal individuals were removed, leaving the diurnal ones to self-feed in smaller groups. Again, no switch in activity occurred, but the diurnal trout continued to release the triggers in daylight. When food was available at all hours, individual fish seemed to gain little by releasing the demand feeders during a specific part of the light–dark cycle. The diurnal individuals were significantly (p < 0.05) larger than the nocturnal ones in the first round, but there were no significant (p > 0.05) differences in specific growth rate between the two categories. During the second round, there was no difference in mass between nocturnal and diurnal individuals, whereas the former had a significantly (p < 0.05) higher growth rate. The ecological benefits of dualism in feeding activity within groups of fish are discussed.
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Teklemariam, Mebrat, and Bezawork Afework. "Abundance and diurnal activity patterns of hooded vulture (Necrosyrtes monachus Temminck,) in Addis Ababa abattoirs enterprise, Addis Ababa, Ethiopia." SINET: Ethiopian Journal of Science 44, no. 1 (2021): 129–34. http://dx.doi.org/10.4314/sinet.v44i1.12.
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Hooded vulture (Necrosyrtes monachus) is an African endemic scavenger listed as Critically Endangered species. The population is declining across its range and there is threat of significant decline in population and distribution in Ethiopia. Little efforts have been made to properly document the status of vulture population and their diurnal activity patterns in the country for ensuring long term conservation measures. A study was conducted in Addis Ababa Abattoirs enterprise, Ethiopia from November 2019 to January 2020 to investigate the abundance and diurnal activity patterns of hooded vultures. The abundance of these vultures was estimated by direct counts method at their feeding sites and scan sampling was employed to study the diurnal activity patterns of hooded vultures from dawn to dusk. Hooded vulture mean abundance was 216±40 at the abattoir. Their diurnal activity pattern showed that they were observed feeding, resting (perching, watching and basking), preening, roosting and others activities such as walking, drinking, chasing and flying. They spent 37.73% of their time in resting followed by others (including walking, drinking, chasing and flying) (27.73%). The major threat recorded for theses vultures in the abattoir includes shortage of food, human disturbances, negative attitudes and lack of awareness on the importance of the species. Further ecological studies and impacts of human activities on Addis Ababa Abattoirs enterprise should be conducted for the conservation of hooded vulture and other conspecifics in the area.
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Zhou, Rui, Richard Sicher, and Bruno Quebedeaux. "Diurnal changes in carbohydrate metabolism in mature apple leaves." Functional Plant Biology 28, no. 11 (2001): 1143. http://dx.doi.org/10.1071/pp00163.
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Net photosynthesis, individual carbohydrate concentrations, and the activities of some enzymes involved in carbohydrate biosynthesis were monitored in mature apple leaves at regular intervals throughout a natural day/night cycle. Sorbitol was the major carbohydrate in mature apple leaves. Its concentration increased gradually after dawn and reached its highest level of 18.0 mg g –1 fresh weight, and then declined to its lowest level of 9.6 mg g–1 at the end of the dark period. Starch also showed a similar diurnal pattern with a lower maximum of 4.6 mg g –1 fresh weight and a minimum of 1.8 mg g –1 fresh weight. Aldose-6-phosphate reductase (A6PR) activity showed significant diurnal fluctuations, whereas sucrose-phosphate synthase (SPS) activity, under both saturating and limiting substrate conditions, showed no variations. The highest A6PR activity under natural light conditions appeared at 1000 h with 37.2 µmol h –1 g ––1fresh weight, which was about 30% higher than that in the night. The diurnal alteration of A6PR activity was also found under controlled environmental conditions in growth chambers. Treatments of 14/10 h light/dark photoperiod, continuous light and continuous darkness, did not change the pattern of diurnal variation in A6PR activity. Significant correlation between A6PR activity, sorbitol concentration and photosynthetic rate suggested that the processes of photosynthesis and carbohydrate biosynthesis are coordinated.
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Sandoval-Serés, Elisa, Khiavett Sánchez-Pinzón, and Rafael Reyna-Hurtado. "Waterhole use and diel activity pattern of ocelots in Calakmul rainforest, Mexico." Revista Mexicana de Biodiversidad 93 (September 30, 2022): e933930. http://dx.doi.org/10.22201/ib.20078706e.2022.93.3930.
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We aimed to evaluate the temporal and spatial use of waterholes by ocelots in Calakmul Biosphere Reserve (CBR), Mexico. From 2014 to 2017, we monitored 11 waterholes with camera traps. We compared diel activity patterns with circular statistics depending on waterholes’ level of human intensity and distance to the Calakmul road, seasonality, and sex. We identified 40 different ocelots. Four waterholes were the most important ones, being 2 of them close to the road. Individuals took on average 19 days to return to waterholes. The diel activity of ocelots was 63.67% nocturnal, 20.70% crepuscular and 15.60% diurnal, and they were more diurnal in waterholes distant from the road. Their activity pattern was bimodal and it did not change between any of the categories tested. This is the first study to determine the spatial and temporal activity of ocelots in waterholes of Mexico. Ocelots are mainly nocturnal, and this pattern is conserved throughout CBR, however, they are able to adjust slightly their activity depending on extrinsic factors, such as an increased human presence. In the Calakmul region, all waterholes are crucial, and we particularly emphasize the conservation of the most important waterholes for ocelots, especially the ones close to the road.
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Deshler, John F., Eric D. Forsman, and James K. Swingle. "DIURNAL ACTIVITY PATTERN OF A PAIR OF BREEDING NORTHERN PYGMY-OWLS." Northwestern Naturalist 100, no. 3 (2019): 176. http://dx.doi.org/10.1898/1051-1733-100.3.176.
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Tulen, Joke H. M., Hugo J. Duivenvoorden, Marieke J. Gieteling, et al. "Effect of Personality Dimensions on the Diurnal Pattern of Motor Activity." Journal of Personality 70, no. 2 (2002): 233–48. http://dx.doi.org/10.1111/1467-6494.05004.
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Glaser, Andrea M., Cruz Reyes-Vázquez, Bertha Prieto-Gómez, Keith Burau, and Nachum Dafny. "Morphine administration and abrupt cessation alter the behavioral diurnal activity pattern." Pharmacology Biochemistry and Behavior 101, no. 4 (2012): 544–52. http://dx.doi.org/10.1016/j.pbb.2012.02.015.
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DeGregorio, Brett A., Jinelle H. Sperry, Daniel P. Valente, and Patrick J. Weatherhead. "Facultative nocturnal behaviour in snakes: experimental examination of why and how with Ratsnakes (Elaphe obsoleta) and Racers (Coluber constrictor)." Canadian Journal of Zoology 92, no. 3 (2014): 229–37. http://dx.doi.org/10.1139/cjz-2013-0255.
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Diel activity patterns are often fixed within species such that most animals can be classified as diurnal, crepuscular, or nocturnal, and have sensory abilities that reflect when they are active. However, many snake species appear capable of switching between diurnal and nocturnal activity. Here, we evaluate the hypothesis that some species are constrained in their activity by the sensory cues used for foraging. We experimentally assessed differences between two sympatric snake species in their ability to alter diel activity patterns, to address why those snakes that switch do so (do thermal constraints force them to be active in otherwise nonpreferred conditions?), and to explore how sensory abilities to locate prey facilitate or constrain this shift. Ratsnakes (Elaphe obsoleta (Say in James, 1823)) were active when temperature was optimal, regardless of light level, suggesting their activity pattern is genuinely plastic. Consistent with our predictions, Ratsnakes successfully detected prey in low and high light using visual or chemical cues, and were most successful when cues were coupled. Racers (Coluber constrictor L., 1758) were almost exclusively diurnal, regardless of temperature, and became less active when daytime temperatures were suboptimal. The ability of Ratsnakes to shift activity may confer a foraging advantage and should buffer Ratsnakes and similarly flexible species from climate change, whereas climate change may pose a more serious threat to inflexible species such as Racers.
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Bourgoin, G., M. Garel, P. Blanchard, D. Dubray, D. Maillard, and J. M. Gaillard. "Daily responses of mouflon (Ovis gmelini musimon ×Ovis sp.) activity to summer climatic conditions." Canadian Journal of Zoology 89, no. 9 (2011): 765–73. http://dx.doi.org/10.1139/z11-046.
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Investigating the factors shaping the activity of large herbivores is of prime importance because changes in their activity patterns may indicate physiological stress, which can affect reproduction and survival of individuals, and thereby population growth. Although climatic conditions are known to impact the activity patterns of large herbivores, few studies have investigated this relationship at a fine temporal scale. From a continuous monitoring of activity, we assessed the influence of temperature and wind on the summer activity of female mouflon ( Ovis gmelini musimon Pallas, 1811 × Ovis sp.) facing summer droughts. Females showed a marked bimodal activity pattern, with activity peaks occurring after dawn and before dusk. When temperature increased and wind speed decreased, the morning activity peak occurred earlier, while the evening activity peak was delayed. Hence, under stressing climatic conditions, female mouflon decreased their diurnal activity while increasing their nocturnal activity. However, this nocturnal increase did not prevent the activity rate over 24 h to decrease during hot nonwindy days compared with cool windy days. Although the occurrence of wind mitigated the negative influence of heat on the diurnal activity, wind had no effect at the daily scale. These findings emphasize the importance of working at different temporal scales when assessing the activity patterns of free-ranging vertebrates.
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Morse, Allen D., James C. Russell, Terry W. M. Hunt, George O. Wood, W. Frank Epling, and W. David Pierce. "Diurnal variation of intensive running in food-deprived rats." Canadian Journal of Physiology and Pharmacology 73, no. 10 (1995): 1519–23. http://dx.doi.org/10.1139/y95-210.
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Manipulation of the food supply can induce either intense hyperactive wheel running or a fatal activity anorexia in rats that is strongly analogous to that seen in humans. The abnormal behaviour is accompanied by alterations in the diurnal pattern of activity. As part of a detailed study of hyperactivity and anorexia, spontaneous wheel running by male rats was studied under three conditions: ad libitum feeding; restriction to 15 g of food per day; and restriction to a single 90-min meal per day. Ad libitum fed rats increased their running at the rate of 440 ± 60 m/day per day, stabilizing after day 10 at 6045 ± 3010 m/day. The running occurred in short bursts throughout the dark period and at the beginning of the light period. Rats restricted to 15 g/day increased their running at the significantly greater (p < 0.001) rate of 1230 ± 120 m/day per day, reaching 12 200 ± 4090 m/day by day 10 and thereafter stabilizing at 13 600 ± 4 160 m/day. The running was initially triphasic and confined to the dark period but eventually progressed to a biphasic pattern. The rats restricted to a single 90-min access period to food each day showed an even greater rate of increase in running, attaining 1930 ± 288 m/day per day (p < 0.02 vs. 15 g/day group). These animals decreased eating and decompensated by day 4. The diurnal pattern of activity was disturbed from day 1 of the protocol, and by day 4 the rats ran essentially continuously throughout the daily cycle. The sensitivity to hyperactivity is a function of the severity of food restriction in this animal model of hyperactivity. It is paralleled by a marked disturbance of the diurnal pattern of activity, suggesting that the hyperactivity is related to a basic central nervous system dysfunction.Key words: hyperactivity, diurnal variation, rat.
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Baldellou, Maribel, and Ana Adan. "Diurnal and Seasonal Variations in Vervet Monkeys' Activity." Psychological Reports 83, no. 2 (1998): 675–85. http://dx.doi.org/10.2466/pr0.1998.83.2.675.
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This paper analyzed seasonal and diurnal differences in feeding, locomotion, inactivity, and social grooming of adult and subadult free-ranging vervet monkeys in Natal (38°35′S and 31°46′E). Breaking down hourly activity budgets from the perspective of reproductive seasons (birth, premating, and mating seasons) which correspond to environmental conditions in Natal, we obtained several results. First, there were diurnal variations for all the behaviours in all seasons studied, except for inactivity during the mating season when days were shorter and there was greater food shortage and sexual competition. Second, the seasonal influence on the hourly periods of increased activity could not be explained solely by the photoperiod or by the other climatic Factors analyzed. Finally, over-all seasonal differences in activity were mainly reflected by the hourly distribution of feeding in the morning and the pattern of inactivity throughout the day. Therefore, rhythms in activity should be understood in terms of adaptation to both climatic constraints and other unrelated metabolic requirements.
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Piper, David, and Michael Kunz. "Spatiotemporal variability of lightning activity in Europe and the relation to the North Atlantic Oscillation teleconnection pattern." Natural Hazards and Earth System Sciences 17, no. 8 (2017): 1319–36. http://dx.doi.org/10.5194/nhess-17-1319-2017.
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Abstract. Comprehensive lightning statistics are presented for a large, contiguous domain covering several European countries such as France, Germany, Austria, and Switzerland. Spatiotemporal variability of convective activity is investigated based on a 14-year time series (2001–2014) of lightning data. Based on the binary variable thunderstorm day, the mean spatial patterns of lightning activity and regional peculiarities regarding seasonality are discussed. Diurnal cycles are compared among several regions and evaluated with respect to major seasonal changes. Further analyses are performed regarding interannual variability and the impact of teleconnection patterns on convection. Mean convective activity across central Europe is characterized by a strong northwest-to-southeast gradient with pronounced secondary features superimposed. The zone of maximum values of thunderstorm days propagates southwestward along the southern Alpine range from April to July. Diurnal cycles vary substantially between both different months and regions, particularly regarding the incidence of nighttime lightning. The North Atlantic Oscillation (NAO) is shown to have a significant impact on convective activity in several regions, which is primarily caused by variations of the large-scale lifting pattern in both NAO phases. This dynamical effect is partly compensated for by thermodynamical modifications of the pre-convective environment. The results point to a crucial role of large-scale flow in steering the spatiotemporal patterns of convective activity.
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Xie, Haimei, Xiaomei Zheng, Ye Huang, et al. "Diurnal pattern of salivary alpha-amylase and cortisol under citric acid stimulation in young adults." PeerJ 10 (April 12, 2022): e13178. http://dx.doi.org/10.7717/peerj.13178.
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Background Saliva composition has diurnal variations. Citric acid stimulation plays a major role in the change of salivary flow rate and salivary composition. However, diurnal variations and sex differences in salivary alpha-amylase (sAA), pH, salivary flow rate (SFR), and salivary cortisol before and after citric acid stimulation remain unclear. Methods We recruited 30 healthy volunteers, including 15 women (24.7 ± 1.0 years old) and 15 men (25.3 ± 1.3 years old). At four time points (T1, 7:00; T2, 10:00; T3, 16:00; and T4, 20:00), saliva was collected from healthy volunteers before and after citric acid stimulation; and sAA, pH, SFR and salivary cortisol were measured and compared between men and women. Results There were circadian fluctuations in sAA activity, SFR, pH, and cortisol level both before and after citric acid stimulation, and the diurnal fluctuations of these indexes were not affected by citric acid stimulation. There were significant differences in salivary cortisol between men and women before and after acid stimulation in T1. Neither SFR nor pH showed sex-related differences before or after acid stimulation. The variation trend of sAA activity was contrary to that of cortisol, with a significant negative correlation. Conclusions Our data suggest that sAA and cortisol showed diurnal fluctuation, and the variation characteristics of male and female under resting state and acid stimulation were basically the same. The variation trend of salivary alpha-amylase activity was opposite to that of cortisol, with significant negative correlation. Our findings may enable the selection of the correct sampling time for research and the selection of appropriate sampling strategies in studies investigating chronic psychosocial conditions.
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Kawakami, Shigehisa, Yohei Kumazaki, Yosuke Manda, Kazuhiro Oki, and Shogo Minagi. "Specific Diurnal EMG Activity Pattern Observed in Occlusal Collapse Patients: Relationship between Diurnal Bruxism and Tooth Loss Progression." PLoS ONE 9, no. 7 (2014): e101882. http://dx.doi.org/10.1371/journal.pone.0101882.
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Trinh, T. N., S. R. Kohllepel, P. B. Yang, K. D. Burau, and N. Dafny. "Adult female rats' altered diurnal locomotor activity pattern following chronic methylphenidate treatment." Journal of Neural Transmission 120, no. 12 (2013): 1717–31. http://dx.doi.org/10.1007/s00702-013-1063-4.
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García-Allegue, R., P. Lax, A. M. Madariaga, and J. A. Madrid. "Locomotor and feeding activity rhythms in a light-entrained diurnal rodent, Octodon degus." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 277, no. 2 (1999): R523—R531. http://dx.doi.org/10.1152/ajpregu.1999.277.2.r523.
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The wheel running (WR) and feeding activity (FA) of Octodon degus, a new laboratory rodent characterized by its diurnal habits, were recorded under different lighting conditions. Under 12:12-h light-dark (LD 12:12) cycles, WR activity exhibited a crepuscular pattern with two peaks, M and E, associated with “dawn” and “dusk,” respectively. In both cases, an anticipatory activity was patent, suggesting that, beside the masking effect of LD transitions, both peaks have an endogenous origin. This pattern, which was also observed under a skeleton photoperiod (LD 0.5:11.5), became unimodal after LD 0.5:23.5 and constant darkness (DD) exposure. Simultaneously, FA showed an arrhythmic pattern in most animals, especially under DD, when none of the animals exhibited a significant circadian rhythm. The existence of two groups of oscillators, or two oscillators, would explain most properties of the WR rhythms noted in this species. Our results show that the degu’s temporal feeding strategy seems mainly arrhythmic, whereas its WR pattern is driven by a strongly circadian bimodal rhythm.
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Sivan, S., C. Neidlinger-Wilke, K. Würtz, A. Maroudas, and J. P. G. Urban. "Diurnal fluid expression and activity of intervertebral disc cells." Biorheology: The Official Journal of the International Society of Biorheology 43, no. 3-4 (2006): 283–91. http://dx.doi.org/10.1177/0006355x2006043003004012.
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The intervertebral discs are large cartilaginous structures situated between the vertebral bodies, occupying around one third of the length of the spinal column. They act as the joints of the spine and carry mechanical load arising from body weight and muscle activity. Loads change with every alteration of posture and activity and the discs thus undergo a diurnal loading pattern with high loads on the discs during the day's activity and low loads on it at night during rest. As the disc is an osmotic system, around 25% of the disc's fluid is expressed and re-imbibed during each diurnal cycle with consequent changes in the osmotic environment of the disc cells. Here, present information on the effect of osmotic changes in disc cell metabolism is reviewed; results indicate that prevailing osmolarity is a powerful regulator of disc cell activity.
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Aðalgeirsdóttir, G., A. M. Smith, T. Murray, et al. "Tidal influence on Rutford Ice Stream, West Antarctica: observations of surface flow and basal processes from closely spaced GPS and passive seismic stations." Journal of Glaciology 54, no. 187 (2008): 715–24. http://dx.doi.org/10.3189/002214308786570872.
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AbstractHigh-resolution surface velocity measurements and passive seismic observations from Rutford Ice Stream, West Antarctica, 40 km upstream from the grounding line are presented. These measurements indicate a complex relationship between the ocean tides and currents, basal conditions and ice-stream flow. Both the mean basal seismicity and the velocity of the ice stream are modulated by the tides. Seismic activity increases twice during each semi-diurnal tidal cycle. The tidal analysis shows the largest velocity variation is at the fortnightly period, with smaller variations superimposed at diurnal and semi-diurnal frequencies. The general pattern of the observed velocity is two velocity peaks during each semi-diurnal tidal cycle, but sometimes three peaks are observed. This pattern of two or three peaks is more regular during spring tides, when the largest-amplitude velocity variations are observed, than during neap tides. This is the first time that velocity and level of seismicity are shown to correlate and respond to tidal forcing as far as 40 km upstream from the grounding line of a large ice stream.
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García-Solís, Fernando, Alfredo H. Zúñiga, Jaime R. Rau, Francisco Encina-Montoya, and Cristóbal Garcés. "Temporal interactions among carnivores in an anthropized landscape of the coastal mountain range in southern Chile." Folia Oecologica 52, no. 1 (2025): 14–21. https://doi.org/10.2478/foecol-2025-0002.
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Abstract The structuring of carnivore assemblages is based on the partitioning of niche axes, where the activity pattern is relevant for their coexistence. However, the continuous degradation of habitats, and the human presence (and exotic species) limit the availability of resources. Therefore, these species must readjust their requirements to minimize interactions derived from competition. For two years, activity patterns of two native carnivores (the cougar Puma concolor and the chilla fox Lycalopex griseus), one exotic carnivore (the domestic dog Canis lupus familiaris) and people were evaluated in an anthropogenic landscape in southern Chile. A differentiation was observed in the circadian cycle of the species, where the fox was predominantly nocturnal, while the cougar maintained a random activity pattern, in contrast to the dog and humans, which were the most diurnal. The ecological implications derived from the observed patterns are discussed, mainly in relation to the interference exerted by the exotic species.
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Rado, Rony, Uri Shanas, Ido Zuri, and Joseph Terkel. "Seasonal activity in the blind mole rat (Spalax ehrenbergi)." Canadian Journal of Zoology 71, no. 9 (1993): 1733–37. http://dx.doi.org/10.1139/z93-245.
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The locomotor activity pattern of the blind mole rat Spalax ehrenbergi was determined in its natural habitat by means of a radiotelemetric device. Twelve adult mole rats were fitted with radiotelemetric transmitters (9 during winter and 3 during summer) and tracked for 5 noncontinuous days during which air and soil temperatures were measured. Mole rats were found to have a diurnal monophasic locomotor activity pattern with activity peaks from 08:00 to 13:00 and from 11:00 to 19:00 during summer and winter, respectively. Activity periods were punctuated by several rest breaks and, conversely, rest periods were interrupted by short spells of activity. Duration of activity was 6.6 ± 0.4 h (mean ± SD) in summer and 7.9 ± 2.3 h in winter. In the laboratory, mole rats were found to entrain their activity, under constant dim light, to a single daily 20-s light pulse. Moreover, such a light pulse given only once every 3 days was found to provide a stimulus sufficient to entrain the mole rats' locomotor activity. We propose that brief light pulses perceived through the mole rats' rudimentary eyes while they are pushing excess soil out of the tunnel to the ground surface, are the main Zeitgeber that entrains their locomotor activity to the diurnal pattern. Air and soil temperatures are the secondary cues that finely tune the activity to the morning during summer and the late afternoon during winter.
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KLIMES–DOUGAN, BONNIE, PAUL D. HASTINGS, DOUGLAS A. GRANGER, BARBARA A. USHER, and CAROLYN ZAHN–WAXLER. "Adrenocortical activity in at-risk and normally developing adolescents: Individual differences in salivary cortisol basal levels, diurnal variation, and responses to social challenges." Development and Psychopathology 13, no. 3 (2001): 695–719. http://dx.doi.org/10.1017/s0954579401003157.
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The purpose of this study was to examine adrenocortical activity (basal, diurnal variation, and responses to social stressors) in adolescents at risk for psychopathology. Salivary cortisol levels were examined in normally developing and at-risk youth with internalizing and externalizing symptoms ranging from subclinical to clinical levels. Adolescents showed expected patterns of diurnal variation, with high early morning cortisol levels and a pattern of decline throughout the day. Females showed higher midday and late afternoon levels than males, and these patterns interacted with risk status. Internalizing problems sometimes were associated with gradual rather than steep declines in basal cortisol production. Both immediate and delayed cortisol reactivity to a social performance stressor were associated with internalizing symptoms. There was no evidence of relations between externalizing problems and underarousal of the hypothalamic–pituitary–adrenal (HPA) system. These and other results suggest that gender is an important moderating factor linking psychopathology, development, and context with HPA axis functioning in adolescence.
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Selvan, Kangaraj Muthamizh, Bawa Mothilal Krishnakumar, Pasiyappazham Ramasamy, and Thangadurai Thinesh. "Diel activity pattern of meso-carnivores in the suburban tropical dry evergreen forest of the Coromandel Coast, India." Journal of Threatened Taxa 11, no. 8 (2019): 13960–66. http://dx.doi.org/10.11609/jott.4850.11.8.13960-13966.
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Sympatric and similar body-sized species exhibit interspecific competition for resources. The present study investigated diel activity of five meso-carnivore species (Canis aureus, Felis chaus, Paradoxurus hermaphroditus, Viverricula indica, and Herpestes edwardsii) in a human-dominated region of Auroville and around Pondicherry University using camera-trap survey data. Diel activity pattern and overlap were estimated using the kernel density method. The Jungle Cat Felis chaus and the Golden Jackal Canis aureus exhibited cathemeral diel activity with a high overlap between them (Δ̂1 = 0.78). The Indian Grey Mongoose Herpestes edwardsii displayed a diurnal activity pattern and had low overlap with the Small Indian Civet Viverricula indica (Δ̂1 = 0.34). Moderate overlap was found between the Small Indian Civet and the Palm Civet Paradoxurus hermaphroditus (Δ̂1 = 0.32). Therefore, diel activity patterns of mesocarnivores indicate inter- and intra-specific trade-off competition avoidance resulting in successful foraging. The present camera-trap survey has provided insights into diel activity patterns and more attention is required to be paid to the study of feeding and breeding ecology of these species in human-dominated landscapes.
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Mikkonen, Santtu, Zoltán Németh, Veronika Varga, et al. "Decennial time trends and diurnal patterns of particle number concentrations in a central European city between 2008 and 2018." Atmospheric Chemistry and Physics 20, no. 20 (2020): 12247–63. http://dx.doi.org/10.5194/acp-20-12247-2020.
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Abstract. Multiple atmospheric properties were measured semi-continuously in the Budapest platform for Aerosol Research and Training laboratory, which represents the urban background for the time interval of 2008–2018. Data of 6 full measurement years during a decennial time interval were subjected to statistical time trend analyses by an advanced dynamic linear model and a generalized linear mixed model. The main interest in the analysed data set was on particle number concentrations in the diameter ranges from 6 to 1000 nm (N6−1000), from 6 to 100 nm (N6−100, ultrafine particles), from 25 to 100 nm (N25−100) and from 100 to 1000 nm (N100−1000). These data were supported by concentrations of SO2, CO, NO, NOx, O3, PM10 mass, as well as air temperature, relative humidity, wind speed, atmospheric pressure, global solar radiation, condensation sink, gas-phase H2SO4 proxy, classes of new aerosol particle formation (NPF), and growth events and meteorological macro-circulation patterns. The trend of the particle number concentrations derived as a change in the statistical properties of background state of the data set decreased in all size fractions over the years. Most particle number concentrations showed decreasing decennial statistical trends. The estimated annual mean decline of N6−1000 was (4–5) % during the 10-year measurement interval, which corresponds to a mean absolute change of −590 cm−3 in a year. This was interpreted as a consequence of the decreased anthropogenic emissions at least partly from road traffic alongside household heating and industry. Similar trends were not observed for the air pollutant gases. Diurnal statistical patterns of particle number concentrations showed tendentious variations, which were associated with a typical diurnal activity–time pattern of inhabitants in cities, particularly of vehicular road traffic. The trend patterns for NPF event days contained a huge peak from late morning to late afternoon, which is unambiguously caused by NPF and growth processes. These peaks were rather similar to each other in the position, shape and area on workdays and holidays, which implies that the dynamic and timing properties of NPF events are not substantially influenced by anthropogenic activities in central Budapest. The diurnal pattern for N25−100 exhibited the largest relative changes, which were related to particle emissions from high-temperature sources. The diurnal pattern for N100−1000 – which represents chemically and physically aged particles of larger spatial scale – were different from the diurnal patterns for the other size fractions.
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Fodhl Algahim, Mohame, Pamela Boi Yang, Keith Dean Burau, Allan Craig Swann, and Nachum Dafny. "Repetitive Ritalin Treatment Modulates the Diurnal Activity Pattern of Young SD Male Rats." Central Nervous System Agents in Medicinal Chemistry 10, no. 3 (2010): 247–57. http://dx.doi.org/10.2174/1871524911006030247.
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Wronski, Torsten. "Habitat preference and diurnal activity pattern in the Sand Partridge,Ammoperdix heyi heyi." Zoology in the Middle East 48, no. 1 (2009): 35–42. http://dx.doi.org/10.1080/09397140.2009.10638364.
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Cornou, Cécile, and Søren Lundbye-Christensen. "Modeling of sows diurnal activity pattern and detection of parturition using acceleration measurements." Computers and Electronics in Agriculture 80 (January 2012): 97–104. http://dx.doi.org/10.1016/j.compag.2011.11.001.
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Ratovsky, K. G., A. V. Medvedev, and M. V. Tolstikov. "Diurnal, seasonal and solar activity pattern of ionospheric variability from Irkutsk Digisonde data." Advances in Space Research 55, no. 8 (2015): 2041–47. http://dx.doi.org/10.1016/j.asr.2014.08.001.
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Navarrete, Laura, Blake Grisham, Maria Kalyvaki, et al. "Diurnal activity patterns of Black-Necked Stilts (<em>Himantopus mexicanus</em>) during the non-breeding season in the eastern Caribbean." Journal of Caribbean Ornithology 26 (April 18, 2013): 17–21. https://doi.org/10.55431/jco.2013.26.17-21.
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Abstract: Diurnal activity patterns of resident Black-necked Stilts (Himantopus mexicanus) were observed on Guana Island, British Virgin Islands, during October 2010. Stilts were principally engaged in foraging and idle behaviors. The amount of time engaged in particular behaviors was relatively constant throughout the day, except during mid-afternoon when idleness increased and foraging decreased, with a subsequent increase in foraging in the evening. We speculate that the increase in foraging activity was a result of changing prey activity. Keywords: activity pattern, behavior, Black-necked Stilt, Guana Island, Himantopus mexicanus, wetlands Resumen: Patrones de actividad diurna de Himantopus mexicanus durante la temporada no reproductiva en las antillas menores- Los patrones de actividad diurna de individuos residentes de Himantopus mexicanus fueron observados en la isla de Guana, Islas Vírgenes Británicas, durante octubre de 2010. Los individuos estaban ocupados principalmente en conductas de forrajeo e inactivos. La cantidad de tiempo dedicado a conductas particulares fue relativamente constante a lo largo del día, excepto a media tarde cuando se incrementó el descanso y disminuyó el forrajeo con un subsecuente incremento de este último al atardecer. Especulamos que este incremento en la actividad de forrajeo fue el resultado de un cambio en la actividad de las presas. Palabras clave: conducta, isla de Guana, Himantopus mexicanus, humedales, patrones de actividad Résumé: Rythmes d’activité diurne de l’échasse d’amérique (Himantopus mexicanus) en dehors de la saison de reproduction dans l’est de la caraïbe- Les rythmes d’activité diurne des Échasses d’Amérique (Himantopus mexicanus) sédentaires ont été observés sur Guana Island, aux Îles Vierges britanniques, en octobre 2010. La recherche de nourriture et le repos constituaient les principaux comportements des échasses. La durée consacrée à des comportements particuliers était relativement constante au cours de la journée, sauf en milieu d’après-midi où les durées de repos augmentaient et celles de recherche de nourriture diminuaient, suivies par une nouvelle augmentation du temps consacré à la recherche de nourriture dans la soirée. L’augmentation de l’activité de recherche de nourriture pourrait être le résultat de l’évolution des activités des proies. Mots clés: comportement, Échasse d’Amérique, Guana Island, Himantopus mexicanus, rythme d’activité, zoneshumides
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Tuf, I. H., P. Dedek, and M. Veselý. "Does the diurnal activity pattern of carabid beetles depend on season, ground temperature and habitat?" Archives of Biological Sciences 64, no. 2 (2012): 721–32. http://dx.doi.org/10.2298/abs1202721t.
Full textAbstract:
The influence of season, ground temperature and habitat on diurnal epigeic activity of ground beetles (Coleoptera: Carabidae) in floodplain forest and neighboring clear-cut area was studied in late spring and early autumn by pitfall trapping. Among the material collected were 35 species of ground beetles. We recorded a significant influence of daytime factors on epigeic activity in 16 species. The epigeic activity of 13 species was co-affected by the temperature of the soil surface. The activity of some species differed, depending on season and locality.