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Author Hoglund, J.; Mitkus, M.; Olsson, P.; Lind, O.; Drews, A.; Bloch, N.I.; Kelber, A.; Strandh, M.
Title Owls lack UV-sensitive cone opsin and red oil droplets, but see UV light at night: retinal transcriptomes and ocular media transmittance Type Journal Article
Year 2019 Publication Vision Research Abbreviated Journal Vision Res
Volume 158 Issue (up) Pages 109-119
Keywords Animals; Vision; Birds; owls; Short-eared Owl; tawny owl; boreal owl; Long-eared Owl; Asio otus; Asio flammeus; Strix aluco; Aegolius funereus; cones; Photoreceptors
Abstract Most diurnal birds have cone-dominated retinae and tetrachromatic colour vision based on ultra-violet/violet-sensitive UV/V cones expressing short wavelength-sensitive opsin 1 (SWS1), S cones expressing short wavelength-sensitive opsin 2 (SWS2), M cones expressing medium wavelength-sensitive opsin (RH2) and L cones expressing long wavelength-sensitive opsin (LWS). Double cones (D) express LWS but do not contribute to colour vision. Each cone is equipped with an oil droplet, transparent in UV/V cones, but pigmented by carotenoids: galloxanthin in S, zeaxanthin in M, astaxanthin in L and a mixture in D cones. Owls (Strigiformes) are crepuscular or nocturnal birds with rod-dominated retinae and optical adaptations for high sensitivity. For eight species, the absence of functional SWS1 opsin has recently been documented, functional RH2 opsin was absent in three of these. Here we confirm the absence of SWS1 transcripts for the Long-eared owl (Asio otus) and demonstrate its absence for the Short-eared owl (Asio flammeus), Tawny owl (Strix aluco) and Boreal owl (Aegolius funereus). All four species had transcripts of RH2, albeit with low expression. All four species express all enzymes needed to produce galloxanthin, but lack CYP2J19 expression required to produce astaxanthin from dietary precursors. We also present ocular media transmittance of the Eurasian eagle owl (Bubo bubo) and Short-eared owl and predict spectral sensitivities of all photoreceptors of the Tawny owl. We conclude that owls, despite lacking UV/V cones, can detect UV light. This increases the sensitivity of their rod vision allowing them, for instance, to see UV-reflecting feathers as brighter signals at night.
Address Department of Biology, Lund University, Lund, Sweden
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0042-6989 ISBN Medium
Area Expedition Conference
Notes PMID:30825468 Approved no
Call Number GFZ @ kyba @ Serial 2245
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Author Arendt, J.; Middleton, B.
Title Human seasonal and circadian studies in Antarctica (Halley, 75 degrees S) Type Journal Article
Year 2018 Publication General and Comparative Endocrinology Abbreviated Journal Gen Comp Endocrinol
Volume 258 Issue (up) Pages 250-258
Keywords Human Activities; Acclimatization/*physiology; Actigraphy; Adult; Antarctic Regions; Behavior/*physiology; Circadian Rhythm/*physiology; Darkness; Female; Heart Rate/physiology; Humans; Libido; Light; Male; Melatonin/blood; Photoperiod; *Seasons; Sleep/physiology; Young Adult; *Antarctica; *Circadian; *Light; *Melatonin; *Seasonal
Abstract Living for extended periods in Antarctica exposes base personnel to extremes of daylength (photoperiod) and temperature. At the British Antarctic Survey base of Halley, 75 degrees S, the sun does not rise for 110 d in the winter and does not set for 100 d in summer. Photoperiod is the major time cue governing the timing of seasonal events such as reproduction in many species. The neuroendocrine signal providing photoperiodic information to body physiology is the duration of melatonin secretion which reflects the length of the night: longer in the short days of winter and shorter in summer. Light of sufficient intensity and spectral composition serves to suppress production of melatonin and to set the circadian timing and the duration of the rhythm. In humans early observations suggested that bright (>2000 lux) white light was needed to suppress melatonin completely. Shortly thereafter winter depression (Seasonal Affective Disorder or SAD) was described, and its successful treatment by an artificial summer photoperiod of bright white light, sufficient to shorten melatonin production. At Halley dim artificial light intensity during winter was measured, until 2003, at a maximum of approximately 500 lux in winter. Thus a strong seasonal and circadian time cue was absent. It seemed likely that winter depression would be common in the extended period of winter darkness and could be treated with an artificial summer photoperiod. These observations, and predictions, inspired a long series of studies regarding human seasonal and circadian status, and the effects of light treatment, in a small overwintering, isolated community, living in the same conditions for many months at Halley. We found little evidence of SAD, or change in duration of melatonin production with season. However the timing of the melatonin rhythm itself, and/or that of its metabolite 6-sulphatoxymelatonin (aMT6s), was used as a primary marker of seasonal, circadian and treatment changes. A substantial phase delay of melatonin in winter was advanced to summer phase by a two pulse 'skeleton' bright white light treatment. Subsequently a single morning pulse of bright white light was effective with regard to circadian phase and improved daytime performance. The circadian delay evidenced by melatonin was accompanied by delayed sleep (logs and actigraphy): poor sleep is a common complaint in Polar regions. Appropriate extra artificial light, both standard white, and blue enriched, present throughout the day, effectively countered delay in sleep timing and the aMT6s rhythm. The most important factor appeared to be the maximum light experienced. Another manifestation of the winter was a decline in self-rated libido (men only on base at this time). Women on the base showed lower aspects of physical and mental health compared to men. Free-running rhythms were seen in some subjects following night shift, but were rarely found at other times, probably because this base has strongly scheduled activity and leisure time. Complete circadian adaptation during a week of night shift, also seen in a similar situation on North Sea oil rigs, led to problems readapting back to day shift in winter, compared to summer. Here again timed light treatment was used to address the problem. Sleep, alertness and waking performance are critically dependent on optimum circadian phase. Circadian desynchrony is associated with increased risk of major disease in shift workers. These studies provide some groundwork for countering/avoiding circadian desynchrony in rather extreme conditions.
Address Biochemistry and Physiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK. Electronic address: b.middleton@surrey.ac.uk
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0016-6480 ISBN Medium
Area Expedition Conference
Notes PMID:28526480 Approved no
Call Number IDA @ john @ Serial 2248
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Author Cochard, P.; Galstian, T.; Cloutier, C.
Title The proportion of blue light affects parasitoid wasp behavior in LED-extended photoperiod in greenhouses: Increased parasitism and offspring sex ratio bias Type Journal Article
Year 2019 Publication Biological Control Abbreviated Journal Biological Control
Volume 133 Issue (up) Pages 9-17
Keywords Animals
Abstract The increasing use of specific wavelengths involving light-emitting diodes (LEDs) under greenhouses enables to overcome the lack of light during winter months, helping crops photosynthesis or vegetative growth. However, modification of the light environment as well as the photoperiod may also alter directly or indirectly the activity of both beneficial and pest insects that depend on plants. Here, we submitted the parasitic wasp Aphidius ervi and its main host the pea aphid, to 4 ratios of red(R): blue(B) LEDs used to lengthen the photoperiod inside a growth chamber. We recorded the parasitism rate of aphids and the sex ratio of newly emerged wasps to evaluate if A. ervi could remain an efficient biological control agent under modified light environments. We found that increasing the 8 h of photophase to 16 h by supplementing with R/B LEDs increased the daily parasitic activity of the wasp as well as their egg laying behavior. Under the 100R light supplement, about 80% of the emerged adults were males, against 50% under 25R:75B light treatment. These results indicate that A. ervi remains a good biological control agent when the light environment is modified. However, the use of red light to extend the photophase has the potential to negatively affect population dynamics of these parasitoids due to its male-bias impact on the sex ratio.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1049-9644 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2253
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Author Rebke, M.; Dierschke, V.; Weiner, C.N.; Aumüller, R.; Hill, K.; Hill, R.
Title Attraction of nocturnally migrating birds to artificial light: The influence of colour, intensity and blinking mode under different cloud cover conditions Type Journal Article
Year 2019 Publication Biological Conservation Abbreviated Journal Biological Conservation
Volume 233 Issue (up) Pages 220-227
Keywords Animals
Abstract A growing number of offshore wind farms have led to a tremendous increase in artificial lighting in the marine environment. This study disentangles the connection of light characteristics, which potentially influence the reaction of nocturnally migrating passerines to artificial illumination under different cloud cover conditions. In a spotlight experiment on a North Sea island, birds were exposed to combinations of light colour (red, yellow, green, blue, white), intensity (half, full) and blinking mode (intermittent, continuous) while measuring their number close to the light source with thermal imaging cameras.

We found that no light variant was constantly avoided by nocturnally migrating passerines crossing the sea. The number of birds did neither differ between observation periods with blinking light of different colours nor compared to darkness. While intensity did not influence the number attracted, birds were drawn more towards continuous than towards blinking illumination, when stars were not visible. Red continuous light was the only exception that did not differ from the blinking counterpart. Continuous green, blue and white light attracted significantly more birds than continuous red light in overcast situations.

Our results suggest that light sources offshore should be restricted to a minimum, but if lighting is needed, blinking light is to be preferred over continuous light, and if continuous light is required, red light should be applied.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0006-3207 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2255
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Author Murphy, B.A.
Title Circadian and circannual regulation in the horse: Internal timing in an elite athlete Type Journal Article
Year 2019 Publication Journal of Equine Veterinary Science Abbreviated Journal Journal of Equine Veterinary Science
Volume 76 Issue (up) Pages 14-24
Keywords Animals; Mammals; horses
Abstract Biological rhythms evolved to provide temporal coordination across all tissues and organs and allow synchronisation of physiology with predictable environmental cycles. Most important of these are circadian and circannual rhythms, primarily regulated via photoperiod signals from the retina. Understanding the nature of physiological rhythms in horses is crucially important for equine management. Predominantly, we have removed them from exposure to their natural environmental stimuli; the seasonally changing photoperiod, continuous foraging and feeding activity, social herd interactions and the continuous low intensity exercise of a grassland dweller. These have been replaced in many cases with confined indoor housing, regimental feeding and exercise times, social isolation and exposure to lighting that is often erratic and does not come close to mimicking the spectral composition of sunlight. We have further altered seasonal timing cues through the use of artificial lighting programs that impact reproductive behaviour, breeding efficiency and the development of youngstock. Understanding how these new environmental cues (some stronger, some weaker) impact the internal physiology of the horse in the context of the natural endogenous rhythms that evolved over millennia, is key to helping to improve equine health, welfare and performance, now and into the future. This review provides an overview of the field, highlights the recent discoveries related to biological timing in horses and discusses the implications that these findings may have for the production and management of the elite equine athlete.
Address Barbara A. Murphy, School of Agriculture and Food Science, University College Dublin, Dublin 4, Ireland; Barbara.murphy(at)ucd.ie
Corporate Author Thesis
Publisher Elseverier Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0737-0806 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2257
Permanent link to this record