Toen ik geinteresseerd raakte in het bestuderen van het orientatievermogen van postduiven was mijn insteek niet een zoekmachine voor wetenschappelijke artikelen op het internet. Ik ben begonnen om als lossingscoordinator zoveel mogelijk weer- en vluchtgegevens te verzamelen, met de bedoeling de resultaten beter te kunnen begrijpen. Door al deze gegevens op een bepaalde manier te combineren en te vergelijken kwam ik uiteindelijk uit op het spoor van UV als factor die steeds mee verandert(zij het de ene keer positief en de andere keer negatief) met alle andere factoren, waarvan wij duivenliefhebbers weten hoe dat van invloed is op de terugkeer van onze gevleugelde favorieten van wedvluchten. Waarom zou UV dan geen rol spelen in het orientatievermogen van postduiven? Daarmee was mijn interesse gewekt. Ik had ooit eens ergens gelezen dat er onderzoek naar was gedaan en heb dat in een van mijn artikels vermeld. Op die vermelding kreeg ik een reactie van Ing. Hugo Sloot met een aantal gevonden onderzoeken en het webadres van een wetenschappelijke zoekmachine. Vervolgens ben ik aan daar en op een aantal andere wetenschappelijke zoekmachines aan het speuren geweest. Het resultaat was verbluffend. Door de jaren heen zijn er honderden onderzoeken in dat kader uitgevoerd. De meesten werden helaas slechts met titel en onderzoeker genoemd en maar een gering aantal met bijgevoegd uittreksel. Deze heb ik onderstaand ter uwer informatie bijgevoegd. Het resultaat van deze wetenschappelijke onderzoeken is duidelijk: postduiven kunnen ultraviolet licht waarnemen. Sommige onderzoekers gaan een stapje verder en suggereren het verband tussen ultraviolet en het orientatievermogen bij postduiven. De definitieve relatie is echter nog niet aangetoond, doch diverse onderzoekers suggereren dat UV in het orientatievermogen van postduiven mogelijk een belangrijke rol speelt. Vooral omdat wetenschappelijk onderzoek op allerlei andere terreinen nog steeds geen enkel definitief aanknopingspunt heeft opgeleverd.
De uittreksels van de wetenschappelijke onderzoeken zijn in het engels en ik heb ze van geen commentaar voorzien. Bestudeert u ze aandachtig en ik sta open voor uw op- of aanmerkingen. Hoe beter we het orientatievermogen van postduiven begrijpen, hoe beter we het lossingsbeleid bij wedvluchten kunnen optimaliseren in het belang van de postduivensport in het algemeen.
--------------------------------------------------------------------------------
Vision Res 1994 Jun;34(11):1471-8 Ultraviolet vision in birds: what is its function? Bennett AT, Cuthill IC Department of Zoology, University of Oxford, England. Although UV vision was first demonstrated in birds in the early 1970s, its function is still unknown,. Here we review the evidence for UV vision in birds, discuss the special properties of UV light, lay out in detail hypotheses for the function of UV vision in birds and discuss their plausibility. The main hypotheses are that UV vision functions: (i) in orientation, (ii) in foraging and (iii) in signaling. The first receives support from studies of homing pigeons, but it would be unwise to conclude that orientation is UV´s primary function in all birds. It is especially important to test the signalling hypothesis because bird plumage often reflects UV and tests of theories of sexual selection have virtually always assumed that birds perceive plumage "colours" as humans do. A priori this assumption is unlikely to be correct, for unlike humans, birds see in the UV, have at least four types of cones and have a system of oil droplets which filters light entering individual cones.
PMID: 8023459, UI: 94295149
--------------------------------------------------------------------------------
Vision Res 1994 Jun;34(11):1509-14
Biological aspects of bird colouration and avian colour vision including ultraviolet range. Finger E, Burkhardt D Institut fur Zoologie, Universitat Regensburg, Germany. Many diurnal birds possess a set of four spectrally different types of cone photoreceptor. The spectral range of vision is extended into the UV by a UV receptor. We have investigated the spectral properties of plumage colours including the UV by reflection spectroscopy. Some basic general principles of colour vision indicate that plumage colours are tuned to avian colour vision.
PMID: 8023462, UI: 94295152
--------------------------------------------------------------------------------
Biochem J 1998 Feb 15;330 ( Pt 1):541-7
The molecular basis for UV vision in birds: spectral characteristics, cDNA sequence and retinal localization of the UV-sensitive visual pigment of the budgerigar (Melopsittacus undulatus). Wilkie SE, Vissers PM, Das D, Degrip WJ, Bowmaker JK, Hunt DM Department of Molecular Genetics, Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, U.K. Microspectrophotometric (msp) studies have shown that the colour-vision system of many bird species is based on four pigments with absorption peaks in the red, green, blue and UV regions of the spectrum. The existence of a fourth pigment (UV) is the major difference between the trichromacy of humans and the tetrachromacy of such birds, and recent studies have shown that it may play a determining role in such diverse aspects of behaviour as mate selection and detection of food. Avian visual pigments are composed of an opsin protein covalently bound via a Schiff-base linkage to the chromophore 11-cis-retinal. Here we report the cDNA sequence of a UV opsin isolated from an avian species, Melopsittacus undulatus (budgerigar or small parakeet). This sequence has been expressed using the recombinant baculovirus system; the pigment generated from the expressed protein on addition of 11-cis-retinal yielded an absorption spectrum typical of a UV photopigment, with lambdamax 365+/-3 nm. This is the first UV opsin from an avian species to be sequenced and expressed in a heterologous system. In situ hybridization of this sequence to budgerigar retinas selectively labelled a sub-set of UV cones, representing approx. 9% of the total cone population, that are distributed in a semi-regular pattern across the entire retina.
PMID: 9461554, UI: 98129773
--------------------------------------------------------------------------------
Invest Ophthalmol Vis Sci 1980 Nov;19(11):1382-7
Spectral transmission of the ocular media of the pegion (Columba livia). Emmerton J, Schwemer J, Muth I, Schlecht P Spectrophotometric and microspectrophotometric measures of relative spectral transmission were obtained from the cornea, lens, and vitreous body and from the whole eye of young and adult pigeons. Transmission was above 90% throughout the visible spectrum and was maintained at or above 50% into the near-UV at 310 nm. No age-related changes in transmission were found. The results concur with the pigeon´s behavioral UV-detection abilities. PMID: 7429773, UI: 81046234
--------------------------------------------------------------------------------
Genetic analyses of visual pigments of the pigeon. Kawamura S, Blow NS, Yokoyama S
Department of Biology, Syracuse University, Syracuse, New York 13244, USA.
[Medline record in process]
We isolated five classes of retinal opsin genes rh1(Cl), rh2(Cl), sws1(Cl), sws2(Cl), and lws(Cl) from the pigeon; these encode RH1(Cl), RH2(Cl), SWS1(Cl), SWS2(Cl), and LWS(Cl) opsins, respectively. Upon binding to 11-cis-retinal, these opsins regenerate the corresponding photosensitive molecules, visual pigments. The absorbance spectra of visual pigments have a broad bell shape with the peak, being called lambdamax. Previously, the SWS1(Cl) opsin cDNA was isolated from the pigeon retinal RNA, expressed in cultured COS1 cells, reconstituted with 11-cis-retinal, and the lambdamax of the resulting SWS1(Cl) pigment was shown to be 393 nm. In this article, using the same methods, the lambdamax values of RH1(Cl), RH2(Cl), SWS2(Cl), and LWS(Cl) pigments were determined to be 502, 503, 448, and 559 nm, respectively. The pigeon is also known for its UV vision, detecting light at 320-380 nm. Being the only pigments that absorb light below 400 nm, the SWS1(Cl) pigments must mediate its UV vision. We also determined that a nonretinal P(Cl) pigment in the pineal gland of the pigeon has a lambdamax value at 481 nm.
PMID: 10581289, UI: 20050679
--------------------------------------------------------------------------------
Behav Neurosci 1989 Feb;103(1):170-7
Behavioral spectral sensitivities of different retinal areas in pigeons.
Remy M, Emmerton J University of Konstanz, Federal Republic of Germany.
The spectral sensitivity of the red and the yellow retinal fields of head-fixed pigeons was separately measured for wavelengths between 340 and 640 nm by a behavioral perimetric technique. Within this spectral range the mean spectral sensitivity of both fields was found to be maximal at 584 nm and minimal at the lower ultraviolet wavelengths. Differences in sensitivity were found, however, at shorter wavelengths, with the yellow field being more sensitive than the red at wavelengths below 500 nm and especially in the ultraviolet spectral range. These sensitivity differences are discussed in relation to other functional differences between the pigeon´s retinal fields.
PMID: 2923670, UI: 89166066
--------------------------------------------------------------------------------
The relationVision Res 1994 Jun;34(11):1461-70 The relation between celestial colour gradients and the position of the sun, with regard to the sun compass.
Coemans MA, Vos Hzn JJ, Nuboer JF
Neuroethology Group, Utrecht University, The Netherlands.
Colour gradients along the sky caused by atmospheric scattering were measured on sunny days. It is concluded that whereas the shape of the spectral intensity distribution in the short wavelength range is stable, the distribution at longer wavelengths depends on the direction of measurement. We expressed these relative intensity differences as a spectral contrast. This contrast plotted as a function of angular difference with respect to the position of the sun establishes a smooth gradient. We suggest that the pigeon´s UV sensitivity is part of a colour processing system, which is well adapted to employ these gradients in order to derive the sun´s position.
PMID: 8023458, UI: 94295148
--------------------------------------------------------------------------------
J Theor Biol 1998 Jun 7;192(3):341-349 On a Wing and a Vector: a Model for Magnetic Navigation by Homing Pigeons.
Walker MM
Experimental Biology Research Group, School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
The ability of pigeons to home directly from distant, unfamiliar release sites has defied explanation because it has been impossible to identify the mechanism by which the birds determine their current position relative to their home loft. A variety of magnetic effects on homing orientation have implicated magnetic total intensity in position determination but no testable models for magnetic navigation by homing pigeons have resulted. Here, a vector summation model is proposed which identifies a novel coordinate that pigeons could use with magnetic total intensity to determine position. The model makes predictions about the accuracy of homing and patterns of homing orientation over local and regional scales. The model requires no unusual computational or cognitive abilities. It is, however, consistent with a significant volume of pigeon homing data and can be tested in a variety of ways.
Copyright 1998 Academic Press Limited
PMID: 9735253
--------------------------------------------------------------------------------
Proc R Soc Lond B Biol Sci 263: 295-298 (1996)[PMID8920252,MUID97077685] A sensitive optically detected magnetic compass for animals.
D. T. Edmonds
Clarendon Laboratory, Oxford, U.K.
Recent experiments have indicated that at least one important magnetic compass used by many animals for navigation may be located in the eye. Here it is shown that a very sensitive magnetic compass is formed by the incorporation of a small quantity of ferrimagnetic single-domain crystals in a droplet of nematic liquid crystal. Optical detection of the compass output is illustrated by experiment and the predicted properties of a biological compass, based upon these principles, are compared with the known properties of the natural compass. Some experiments that could test the model are described.
--------------------------------------------------------------------------------
Vision Res 34: 1479-1487 (1994)[PMID8023460,MUID94295150] Ultraviolet receptors and color vision: evolutionary implications and a dissonance of paradigms.
T. H. Goldsmith
Department of Biology, Yale University, New Haven, CT 06520-8103.
The discovery of visual sensitivity to UV dates from 1882 and was made in an insect, the ant, but in the last 15 years evidence for photoreceptors maximally sensitive in the UV has been found for many vertebrates. Studies of behavioral responses of insects that possess more than one spectral class of photoreceptor have generated the concept of wavelength-dependent behaviors. These phenomena are distinct from color vision, where chromatic information can be used in multiple associations. Recent work on vertebrates has shown a variety of behavioral responses that appear to be based on specific combinations of spectral classes of receptors. Among these are behavioral responses of birds that are maximally sensitive in the UV, surprising findings since the retinas of birds contain only relatively small numbers of cones with peak sensitivity in the UV. These and other examples, suggestive of both wavelength-dependent behaviors of arthropods and "releasers" of ethology, emphasize anew the need for explanatory concepts that reach beyond the paradigms of primate color vision and for greater attention to the ontogeny of visually-directed behavior in non-mammalian vertebrates. The rapidly accumulating data on the evolutionary relationships of opsins continue to suggest that within specific opsin lineages the absorption maxima of the retinal-based visual pigments lie within about 40 nm of each other. Some UV pigments may provide the first exception to this generalization.
--------------------------------------------------------------------------------
The ultraviolet receptor of bird retinas. Chen DM, Collins JS, Goldsmith TH
The eyes of 15 species of birds from 10 families have some cones maximally sensitive at 370 nanometers in the near-ultraviolet. Spectral sensitivity was measured by recording extracellularly in opened eyecups , and a maximum in the ultraviolet was revealed by selectively adapting the retina with yellow background lights. The 370-nanometer spectral sensitivity function is attributed to receptors because its spectral position does not vary with the strength of adaptation and because it is present when the receptor potentials are isolated from the contributions of higher order retinal neurons by exposing the retina to sodium aspartate. These measurements demonstrate the basis for the ultraviolet sensitivity of birds that has been seen in behavioral experiments, and they provide further evidence that many vertebrates share with insects vision in the near-ultraviolet.
PMID: 6740315, UI: 84250182
--------------------------------------------------------------------------------
The photopic sensitivity of the yellow field of the pigeon´s retina to ultraviolet light. Vos Hzn JJ, Coemans MA, Nuboer JF
Neuro-ethology Group, Utrecht University, The Netherlands.
The photopic spectral sensitivity of the yellow field of the pigeon´s retina to UV light was determined electrophysiologically. The sensitivity curve could be approximated with a model in which the activity of only two cone types were incorporated. In this model, the first type of cone had a maximum sensitivity at 366 nm and was combined with an oil droplet that is completely transparent in the UV wavelength range. The second type had a sensitivity maximum at 415 nm and was associated with an oil droplet cutting off light below 390 nm.
PMID: 8023452, UI: 94295142
--------------------------------------------------------------------------------
The triplex hypothesis of vision. Kashani AA
The duplex theory of vision is concerned with the light level and dual retinal function and refers only to the rod and cone photoreceptor cell systems. There are some visual functions that are not represented by the duplex theory, visual field, or the dark-adaptation curve. There is some confusion as to whether the relationship between visual threshold and bleached pigment is logarithmic or linear. I do not know how many photopigments exist and which pigment and what circuit plays a role in the photoperiod. The complexity of the retina appears to exceed its known functions. Finally, I wonder how the rate of eye growth is regulated. To clarify these concerns, I propose a new cell type and a third mechanism of vision, which has not been described previously to my knowledge. On the basis of this study and the data from the literature, it appears that early retinal ganglion cells cannot project into the visual cortex because the latter has not been formed. Therefore, their axons may progress into the diencephalic centers that are developing and are differentiating. So, there is a novel photoreceptive system with its associated ganglion cells that is the basis for the visual foundation. These are the first photoreceptors to form and are not engaged directly in the visual process, but they play a significant role in nutrition, function, and the well-being of the other parts of the visual apparatus. This, of course, requires much investigation and research. I believe there are three classes of photoreceptors and submit the following triplex hypothesis.
--------------------------------------------------------------------------------
Regeneration of ultraviolet pigments of vertebrates.
Yokoyama S, Radlwimmer FB, Kawamura S
Department of Biology, Syracuse University, NY 13244, USA. syokoyam@mailbox.syr.edu
We report here the regeneration of the visual pigments of mouse, rat, goldfish and pigeon, which have wavelengths of maximal absorption at 359 nm, 358 nm, 359 nm, and 393 nm, respectively. The construction and functional assays of the ultraviolet or near-ultraviolet pigments from a wide range of vertebrate species will allow us to study the molecular bases of ultraviolet vision for the first time.
PMID: 9512349, UI: 98171303
-------------------------------------------------------------------------------- Four cone types characterized by anti-visual pigment antibodies in the pigeon retina. Cserhati P, Szel A, Rohlich P
Second Department of Anatomy, Histology and Embryology, Semmelweis University of Medicine, Budapest, Hungary.
Using three antibodies to visual pigments (monoclonal antibodies COS-1 and OS-2, and a polyclonal anti-opsin serum), four different types of cone cells could be distinguished in the red area (dorsoposterior part with the highest density of cones) of the pigeon retina. Both members of the double cone and the single cone with the red oil droplet were labelled with our monoclonal antibody COS-1 (type I cone). The single cone with the orange oil droplet was positive both with anti-opsin and monoclonal antibody OS-2 (type II cone). The single cone exhibiting a yellowish-green oil droplet, fluorescent in ultraviolet light, also reacted with anti-opsin but lacked the antigenic determinant recognized by OS-2 (type III cone). The thin cone with the small colorless oil droplet was negative with both COS-1 and anti-rhodopsin (type IV cone). We propose that the four immunologically distinguishable cone types correspond to cones expressing visual pigments with different (long-, middle-, short-wavelength and ultraviolet) color sensitivities.
PMID: 2912914, UI: 89108741 |