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Author Buchanan, B.W. url  doi
openurl 
  Title Effects of enhanced lighting on the behaviour of nocturnal frogs Type Journal Article
  Year 1993 Publication Animal Behaviour Abbreviated Journal Animal Behaviour  
  Volume 45 Issue 5 Pages 893-899  
  Keywords animals; amphibians; frogs; grey treefrog; Hyla chrysoscelis; foraging; infrared  
  Abstract Biologists studying anuran amphibians usually assume that artificial, visible light does not affect the behaviour of nocturnal frogs. This assumption was tested in a laboratory experiment. The foraging behaviour of grey treefrogs, Hyla chrysoscelis, was compared under four lighting conditions: ambient light (equivalent to bright moonlight, 0·003 lx), red-filtered light (4·1 lx), low-intensity 'white' light (3·8 lx), and high-intensity 'white' light (12·0 lx). The treatments were chosen to correspond to standard methods of field observation of frog behaviour. The foraging behaviour of frogs in the four treatments was observed using infra-red light that was invisible to the frogs. The ability of the frogs to detect, and subsequently consume prey was significantly reduced under all of the enhanced light treatments relative to the ambient light treatment. Thus, the use of artificial light, within the visible spectrum of the frogs' eyes, can influence the outcome of nocturnal behavioural observations. These results lead to the recommendation that anuran biologists use infra-red or light amplification devices when changes in frogs' visual capabilities may influence the conclusions drawn from a study.  
  Address  
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  Series Volume Series Issue Edition  
  ISSN (up) 0003-3472 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 72  
Permanent link to this record
 

 
Author Rojas, L.M.; McNeil, R.; Cabana, T.; Lachapelle, P. url  doi
openurl 
  Title Diurnal and Nocturnal Visual Capabilities in Shorebirds as a Function of Their Feeding Strategies Type Journal Article
  Year 1999 Publication Brain, Behavior and Evolution Abbreviated Journal Brain Behav Evol  
  Volume 53 Issue 1 Pages 29-43  
  Keywords foraging; Catoptrophorus semipalmatus; Territorial Willets; Black-winged Stilt; Himantopus himantopus; Scolopax minor; Limnodromus griseus; birds; Wilson's Plover; Charadrius wilsonia; Short-billed Dowitcher; Limnodromus griseus  
  Abstract Some shorebird species forage with the same feeding strategy at night and during daytime, e.g. visual pecking in the Wilson's Plover (Charadrius wilsonia) or tactile probing in the Short-billed Dowitcher (Limnodromus griseus). The Limnodromus griseus (Scolopax minor) uses tactile probing, by day and by night, but sometimes pecks for insects during daytime. The Black-winged Stilt (Himantopus himantopus) is a visual pecker, both by day and by night, and sometimes forages tactilely on windy (agitated water surface) moonless nights. Territorial Willets (Catoptrophorus semipalmatus) are visual peckers during daylight and on moonlight conditions but switch to tactile feeding under lower light conditions. It could be postulated that some shorebird species would switch from visual feeding during daytime to tactile foraging at night because they have poor night vision compared to species that are always sight foragers irrespective of the time of the day. This issue was examined by comparing retinal structure and function in the above species. Electroretinograms (ERGs) were obtained at different light intensities from anesthetized birds, and the retinae were processed for histological observations. Based on ERGs, retinal sensitivity, and rod:cone ratios, both plovers and stilts are well adapted for nocturnal vision. Although they have low rod density compared to that of stilts and plovers, Willets and woodcocks have a scotopic retinal sensitivity similar to that of stilts and plovers but rank midway between plovers and dowitchers for the b-wave amplitude. Dowitchers have the lowest scotopic b-wave amplitude and retinal sensitivity and appear the least well adapted for night vision. Based on photopic ERGs and cone densities, although stilts, Willets and dowitchers appear as well adapted for daytime vision, plovers occupy the last rank of all species examined. Compared to the nighttime tactile feeders and those that switch from daytime visual pecking to tactile feeding at night, nighttime sight feeders have a superior rod function and, consequently, potentially superior nocturnal visual capabilities.  
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  ISSN (up) 0006-8977 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 47  
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Author Topping, M.G.; Millar, J.S.; Goddard, J.A. url  doi
openurl 
  Title The effects of moonlight on nocturnal activity in bushy-tailed wood rats (Neotoma cinerea) Type Journal Article
  Year 1999 Publication Canadian Journal of Zoology Abbreviated Journal Can. J. Zool.  
  Volume 77 Issue 3 Pages 480-485  
  Keywords animals; mammals; rats; bushy-tailed wood rat; Neotoma cinerea; Canada; foraging; reproduction; moonlight; predation risk  
  Abstract The nocturnal activity of bushy-tailed wood rats (Neotoma cinerea) was monitored for two breeding seasons (1993 and 1994) in the Canadian Rockies. Radiotelemetry was used under three levels of moonlight to assess two measures of nocturnal activity: (i) the proportion of animals crossing rocky outcrops and entering the surrounding forest to forage, search for mates, or both, and (ii) the distance moved from the den site while in the forest. Males and females exhibited significant differences among moonlight levels, with greater activity on nights of intermediate-level moonlight and less activity on nights with bright or dark moonlight. There was no difference in the proportions of males and females active at any moonlight level. The distances moved from the den did not differ among moonlight levels for either males or females. Having traversed the rocks and entered the forest, individuals moved similar distances regardless of light level. These results suggest that wood rats respond to moonlight only when making the decision to cross rocks and enter the forest. This behaviour presumably serves to counteract the increased risk of predation on bright nights.  
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  ISSN (up) 0008-4301 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 88  
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Author Haag, C.R.; Riek, M.; Hottinger, J.W.; Pajunen, V.I.; Ebert, D. url  doi
openurl 
  Title Genetic diversity and genetic differentiation in Daphnia metapopulations with subpopulations of known age Type Journal Article
  Year 2005 Publication Genetics Abbreviated Journal Genetics  
  Volume 170 Issue 4 Pages 1809-1820  
  Keywords Plants; Aging; Animals; Daphnia/*genetics/*physiology; *Genetic Variation; *Genetics, Population  
  Abstract If colonization of empty habitat patches causes genetic bottlenecks, freshly founded, young populations should be genetically less diverse than older ones that may have experienced successive rounds of immigration. This can be studied in metapopulations with subpopulations of known age. We studied allozyme variation in metapopulations of two species of water fleas (Daphnia) in the skerry archipelago of southern Finland. These populations have been monitored since 1982. Screening 49 populations of D. longispina and 77 populations of D. magna, separated by distances of 1.5-2180 m, we found that local genetic diversity increased with population age whereas pairwise differentiation among pools decreased with population age. These patterns persisted even after controlling for several potentially confounding ecological variables, indicating that extinction and recolonization dynamics decrease local genetic diversity and increase genetic differentiation in these metapopulations by causing genetic bottlenecks during colonization. We suggest that the effect of these bottlenecks may be twofold, namely decreasing genetic diversity by random sampling and leading to population-wide inbreeding. Subsequent immigration then may not only introduce new genetic material, but also lead to the production of noninbred hybrids, selection for which may cause immigrant alleles to increase in frequency, thus leading to increased genetic diversity in older populations.  
  Address Unite d'Ecologie et d'Evolution, Departement de Biologie, Universite de Fribourg, CH-1700 Fribourg, Switzerland. christoph.haag@ed.ac.uk  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
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  ISSN (up) 0016-6731 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:15937138; PMCID:PMC1449778 Approved no  
  Call Number LoNNe @ kagoburian @ Serial 660  
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Author Dwyer, R.G.; Bearhop, S.; Campbell, H.A.; Bryant, D.M. url  doi
openurl 
  Title Shedding light on light: benefits of anthropogenic illumination to a nocturnally foraging shorebird Type Journal Article
  Year 2013 Publication The Journal of Animal Ecology Abbreviated Journal J Anim Ecol  
  Volume 82 Issue 2 Pages 478-485  
  Keywords Artificial light; Dmsp/Ols; foraging strategy; moonlight; shorebirds; birds; animals; foraging; Tringa totanus; common redshank  
  Abstract Intertidal habitats provide important feeding areas for migratory shorebirds. Anthropogenic developments along coasts can increase ambient light levels at night across adjacent inter-tidal zones. Here, we report the effects of elevated nocturnal light levels upon the foraging strategy of a migratory shorebird (common redshank Tringa totanus) overwintering on an industrialised estuary in Northern Europe. To monitor behaviour across the full intertidal area, individuals were located by day and night using VHF transmitters, and foraging behaviour was inferred from inbuilt posture sensors. Natural light was scored using moon-phase and cloud cover information and nocturnal artificial light levels were obtained using geo-referenced DMSP/OLS night-time satellite imagery at a 1-km resolution. Under high illumination levels, the commonest and apparently preferred foraging behaviour was sight-based. Conversely, birds feeding in areas with low levels of artificial light had an elevated foraging time and fed by touch, but switched to visual rather than tactile foraging behaviour on bright moonlit nights in the absence of cloud cover. Individuals occupying areas which were illuminated continuously by lighting from a large petrochemical complex invariably exhibited a visually based foraging behaviour independently of lunar phase and cloud cover. We show that ambient light levels affect the timing and distribution of foraging opportunities for redshank. We argue that light emitted from an industrial complex improved nocturnal visibility. This allowed sight-based foraging in place of tactile foraging, implying both a preference for sight-feeding and enhanced night-time foraging opportunities under these conditions. The study highlights the value of integrating remotely sensed data and telemetry techniques to assess the effect of anthropogenic change upon nocturnal behaviour and habitat use.  
  Address Centre for Ecology and Conservation, School of Biosciences, University of Exeter, Cornwall Campus, Penryn, Cornwall, TR10 9EZ, UK  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN (up) 0021-8790 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:23190422 Approved no  
  Call Number IDA @ john @ Serial 44  
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