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Author Upham, N.S.; Hafner, J.C.
Title (up) Do nocturnal rodents in the Great Basin Desert avoid moonlight? Type Journal Article
Year 2013 Publication Journal of Mammalogy Abbreviated Journal Journal of Mammalogy
Volume 94 Issue 1 Pages 59-72
Keywords Animals; Moonlight
Abstract Rodents make foraging decisions by balancing demands to acquire energy and mates with the need to avoid predators. To identify variations in the risk of predation, nocturnal rodents may use moonlight as a cue of risk. Moonlight avoidance behaviors have been observed in many nocturnal rodent species and are widely generalized to small mammals. However, most prior studies have been limited to 1 species or 1 study site, or occurred in modified habitats. We evaluated desert rodent activity patterns in natural habitats from 1999 to 2006 at 62 study sites across the Great Basin Desert of western North America. Rodent activity was examined by livetrapping in open habitats, using the presence of the sand-obligate kangaroo mouse (Microdipodops) as a habitat indicator. Activity patterns were assessed on 69 nights with clear skies and compared to corresponding moonlight values (moon phase and brightness) to evaluate the frequency of moonlight avoidance. Analyses of total activity of all species in the rodent assemblage relative to moonlight showed a distinct nonrandom (triangular-shaped) pattern but no significant correlations. However, individual genera of desert rodents responded differently to moonlight. Only kangaroo rats (Dipodomys) displayed significant moonlight avoidance patterns; they were maximally active at significantly different moonlight levels and avoided bright moonlight to a greater extent than co-occurring rodents. Moonlight seemed to limit the activity of kangaroo rats most strongly on bright nights during waxing moon phases and summer seasons, but not significantly during the spring or fall seasons, or during waning moons. Rather than avoiding moonlight, the activity of deer mice (Peromyscus), pocket mice (Perognathus), and kangaroo mice may be governed by changes in competition with kangaroo rats. Differences in the body size, locomotion, and space use of kangaroo rats relative to other rodents may explain why different moonlight responses were detected, especially if these traits alter how rodents perceive risk from bright moonlight. These findings indicate that moonlight avoidance may be a specialized trait of kangaroo rats rather than a general behavior of nocturnal desert rodents in the Great Basin.
Address
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ISSN 0022-2372 ISBN Medium
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Notes Approved no
Call Number LoNNe @ kyba @ Serial 1555
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Author Prugh, L.R.; Golden, C.D.
Title (up) Does moonlight increase predation risk? Meta-analysis reveals divergent responses of nocturnal mammals to lunar cycles Type Journal Article
Year 2013 Publication The Journal of Animal Ecology Abbreviated Journal J Anim Ecol
Volume 83 Issue 2 Pages 504-514
Keywords foraging efficiency; giving-up density; illumination; indirect effects; lunar cycles; moonlight; nocturnality; phylogenetic meta-analysis; predation risk; risk-sensitive foraging
Abstract The risk of predation strongly affects mammalian population dynamics and community interactions. Bright moonlight is widely believed to increase predation risk for nocturnal mammals by increasing the ability of predators to detect prey, but the potential for moonlight to increase detection of predators and the foraging efficiency of prey has largely been ignored. Studies have reported highly variable responses to moonlight among species, calling into question the assumption that moonlight increases risk. Here, we conducted a quantitative meta-analysis examining the effects of moonlight on the activity of 59 nocturnal mammal species to test the assumption that moonlight increases predation risk. We examined patterns of lunarphilia and lunarphobia across species in relation to factors such as trophic level, habitat cover preference and visual acuity. Across all species included in the meta-analysis, moonlight suppressed activity. The magnitude of suppression was similar to the presence of a predator in experimental studies of foraging rodents (13.6% and 18.7% suppression, respectively). Contrary to the expectation that moonlight increases predation risk for all prey species, however, moonlight effects were not clearly related to trophic level and were better explained by phylogenetic relatedness, visual acuity and habitat cover. Moonlight increased the activity of prey species that use vision as their primary sensory system and suppressed the activity of species that primarily use other senses (e.g. olfaction, echolocation), and suppression was strongest in open habitat types. Strong taxonomic patterns underlay these relationships: moonlight tended to increase primate activity, whereas it tended to suppress the activity of rodents, lagomorphs, bats and carnivores. These results indicate that visual acuity and habitat cover jointly moderate the effect of moonlight on predation risk, whereas trophic position has little effect. While the net effect of moonlight appears to increase predation risk for most nocturnal mammals, our results highlight the importance of sensory systems and phylogenetic history in determining the level of risk.
Address Institute of Arctic Biology, University of Alaska Fairbanks, 311 Irving 1, Fairbanks, AK, 99775, USA
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Language English Summary Language Original Title
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ISSN 0021-8790 ISBN Medium
Area Expedition Conference
Notes PMID:24102189 Approved no
Call Number IDA @ john @ Serial 83
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Author Kayaba, M.; Iwayama, K.; Ogata, H.; Seya, Y.; Tokuyama, K.; Satoh, M.
Title (up) Drowsiness and low energy metabolism in the following morning induced by nocturnal blue light exposure Type Journal Article
Year 2013 Publication Sleep Medicine Abbreviated Journal Sleep Medicine
Volume 14 Issue Pages e166-e167
Keywords blue light; light exposure; light at night; circadian disruption; drowsiness; melatonin; metabolism; sleep
Abstract Introduction

Evening light exposure debilitates the circadian rhythm and elicits sleep disturbance. Blue light peak wavelengths, around 460 nm, suppress melatonin secretion via the non-image-forming system. The effects of nocturnal blue light exposure on sleep have been reported to be specific but rather small (Münch, 2008). This study was designed to assess the effect of nocturnal blue light exposure on sleep and energy metabolism until noon the next day.

Materials and methods

Nine healthy male volunteers aged between 21 and 25 participated in this study which had a balanced cross-over design with intrasubject comparisons. After 2 h dark adaptation, the subjects were exposed to blue light or no light for 2 h. The peak wavelength of the blue LED was 465 nm, and the horizontal irradiance of the blue light at the height of eye was at 7.02fÊW/cm2. Sleep was recorded polysomnographically, and energy metabolism was measured with a whole body indirect calorimeter.

Results

There were no significant differences in sleep architecture and energy metabolism during the night. However, dozing (stages 1 and 2) was significantly higher (26.0 < 29.4 vs 6.3 < 8.1 min, P < 0.05), and energy expenditure, O2 consumption, CO2 production and the thermic effect of food (increase in energy expenditure after breakfast) were significantly lower the following morning in the blue light exposure subjects.

Conclusion

Contrary to our expectation, sleep architecture and energy metabolism during sleep were not affected by evening exposure to blue light. It might be due to our milder intervention by which subjects in a sitting position did not gaze at the light source set on the ceiling, while the subjects in previous studies directly received brighter light via custom built goggles (Cajochen, 2005; Münch, 2008) or gazed at a light source under the influence of mydriatic agents to dilate pupils (Brainard, 2001). New findings of the present study were that dozing (stages 1 and 2) was significantly increased, and energy metabolism was significantly lower the following morning in blue light exposed subjects. This suggests that modulation of the circadian rhythm is affected by nocturnal blue light exposure and the effect continues in the following daytime even if the intervention was mild.
Address University of Tsukuba, Graduate School of Comprehensive Human Sciences, Japan
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ISSN 1389-9457 ISBN Medium
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Notes Approved no
Call Number IDA @ john @ Serial 349
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Author Dacke, M.; Baird, E.; Byrne, M.; Scholtz, C.H.; Warrant, E.J.
Title (up) Dung beetles use the Milky Way for orientation Type Journal Article
Year 2013 Publication Current Biology : CB Abbreviated Journal Curr Biol
Volume 23 Issue 4 Pages 298-300
Keywords Animals; Beetles/*physiology; *Behavior, Animal; Cues; Feces; *Galaxies; Locomotion; Moon; Motor Activity; Orientation/*physiology; *Stars, Celestial; Vision, Ocular/physiology; Milky Way; insects
Abstract When the moon is absent from the night sky, stars remain as celestial visual cues. Nonetheless, only birds, seals, and humans are known to use stars for orientation. African ball-rolling dung beetles exploit the sun, the moon, and the celestial polarization pattern to move along straight paths, away from the intense competition at the dung pile. Even on clear moonless nights, many beetles still manage to orientate along straight paths. This led us to hypothesize that dung beetles exploit the starry sky for orientation, a feat that has, to our knowledge, never been demonstrated in an insect. Here, we show that dung beetles transport their dung balls along straight paths under a starlit sky but lose this ability under overcast conditions. In a planetarium, the beetles orientate equally well when rolling under a full starlit sky as when only the Milky Way is present. The use of this bidirectional celestial cue for orientation has been proposed for vertebrates, spiders, and insects, but never proven. This finding represents the first convincing demonstration for the use of the starry sky for orientation in insects and provides the first documented use of the Milky Way for orientation in the animal kingdom.
Address Department of Biology, Lund University, 223 62 Lund, Sweden. marie.dacke@biol.lu.se
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ISSN 0960-9822 ISBN Medium
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Notes PMID:23352694 Approved no
Call Number IDA @ john @ Serial 116
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Author van der Burght, B.W.; Hansen, M.; Olsen, J.; Zhou, J.; Wu, Y.; Nissen, M.H.; Sparrow, J.R.
Title (up) Early changes in gene expression induced by blue light irradiation of A2E-laden retinal pigment epithelial cells Type Journal Article
Year 2013 Publication Acta Ophthalmologica Abbreviated Journal Acta Ophthalmol
Volume 91 Issue 7 Pages e537-45
Keywords Apoptosis; Cell Line; Cell Survival; Gene Expression Regulation/*physiology; Humans; Light; Lipofuscin/genetics; Oligonucleotide Array Sequence Analysis; Principal Component Analysis; Pyridinium Compounds; RNA, Messenger/genetics; Real-Time Polymerase Chain Reaction; Retinal Pigment Epithelium/metabolism/pathology/*radiation effects; Retinoids/*genetics; Transcriptome; A2e; age-related macular degeneration; apoptosis; complement cascade; gene expression; retinal pigment epithelial cells; blue light; retinal pigment epithelial; epigenetics
Abstract PURPOSE: Accumulation of bisretinoids as lipofuscin in retinal pigment epithelial (RPE) cells is implicated in the pathogenesis of some blinding diseases including age-related macular degeneration (AMD). To identify genes whose expression may change under conditions of bisretinoid accumulation, we investigated the differential gene expression in RPE cells that had accumulated the lipofuscin fluorophore A2E and were exposed to blue light (430 nm). METHODS: A2E-laden RPE cells were exposed to blue light (A2E/430 nm) at various time intervals. Cell death was quantified using Dead Red staining, and RNA levels for the entire genome was determined using DNA microarrays (Affymetrix GeneChip Human Genome 2.0 Plus). Array results for selected genes were confirmed by real-time reverse-transcriptase polymerase chain reaction. RESULTS: Principal component analysis revealed that the A2E-laden RPE cells irradiated with blue light were clearly distinguishable from the control samples. We found differential regulation of genes belonging to the following functional groups: transcription factors, stress response, apoptosis and immune response. Among the last mentioned were downregulation of four genes that coded for proteins that have an inhibitory effect on the complement cascade: (complement factor H, complement factor H-related 1, complement factor I and vitronectin) and of two belonging to the classical pathway (complement component 1, s subcomponent and complement component 1, r subcomponent). CONCLUSION: This study demonstrates that blue light irradiation of A2E-laden RPE cells can alter the transcription of genes belonging to different functional pathways including stress response, apoptosis and the immune response. We suggest that these molecules may be associated to the pathogenesis of AMD and can potentially serve as future therapeutic targets.
Address Department of International Health, Immunology and Microbiology, Eye Research Unit, University of Copenhagen, Copenhagen, DenmarkDepartment of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, DenmarkDepartment of Ophthalmology, Columbia University, New York, New York, USA
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1755-375X ISBN Medium
Area Expedition Conference
Notes PMID:23742627 Approved no
Call Number IDA @ john @ Serial 346
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