201
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Bleiweiss R. Ultraviolet plumage reflectance distinguishes sibling bird species. Proc Natl Acad Sci U S A 2004; 101:16561-4. [PMID: 15546987 PMCID: PMC534516 DOI: 10.1073/pnas.0406386101] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Realistic studies of plumage color need to consider that many birds can see near-UV light, which normal humans cannot perceive. Although previous investigations have revealed that UV-based plumage reflectance is an important component of various intraspecific social signals, the contribution of UV signals to inter-specific divergence and speciation in birds remains largely unexplored. I describe an avian example of an interspecific phenomenon in which related sympatric species that appear similar to humans (sibling species) differ dramatically in the UV. Both UV video images and physical reflectance spectra indicate that the dorsal plumage of the tanager Anisognathus notabilis has a strong UV-limited reflectance band that readily distinguishes this species from its sibling congener Anisognathus flavinuchus. The main human-visible distinction between A. notabilis (olive back) and coexisting A. flavinuchus (black back) also occurs among different geographic populations of A. flavinuchus. Notably, however, olive- and black-backed taxa interbreed (differentiated populations of A. flavinuchus) unless the additional UV distinction is present (A. notabilis vs. A. flavinuchus). Thus, UV-based reflectance can be an essential component of plumage divergence that relates to reproductive isolation, a key attribute of biological species.
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Affiliation(s)
- Robert Bleiweiss
- Department of Zoology and the Zoological Museum, Birge Hall, 430 Lincoln Drive, University of Wisconsin, Madison, WI 53706, USA.
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202
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Lyytinen A, Lindström L, Mappes J. Ultraviolet reflection and predation risk in diurnal and nocturnal Lepidoptera. Behav Ecol 2004. [DOI: 10.1093/beheco/arh102] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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203
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Jourdie V, Moureau B, Bennett ATD, Heeb P. Ecology: ultraviolet reflectance by the skin of nestlings. Nature 2004; 431:262. [PMID: 15372020 DOI: 10.1038/431262a] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Birds can perceive the reflectance of ultraviolet light by biological structures. Here we show that the skin of the mouth and body of starling nestlings substantially reflects light in the ultraviolet range and that young in which this reflectance is reduced will gain less mass than controls, despite low background levels of ultraviolet and visible light in the nest. We suggest that this ultraviolet reflectance from starling nestlings and its contrast with surrounding surfaces are important for parental decisions about food allocation.
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Affiliation(s)
- Violaine Jourdie
- Department of Ecology & Evolution, University of Lausanne, 1015 Lausanne, Switzerland
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204
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Doucet SM, Shawkey MD, Rathburn MK, Mays HL, Montgomerie R. Concordant evolution of plumage colour, feather microstructure and a melanocortin receptor gene between mainland and island populations of a fairy-wren. Proc Biol Sci 2004; 271:1663-70. [PMID: 15306285 PMCID: PMC1691780 DOI: 10.1098/rspb.2004.2779] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Studies of the patterns of diversification of birds on islands have contributed a great deal to the development of evolutionary theory. In white-winged fairy-wrens, Malurus leucopterus, mainland males develop a striking blue nuptial plumage whereas those on nearby islands develop black nuptial plumage. We explore the proximate basis for this divergence by combining microstructural feather analysis with an investigation of genetic variation at the melanocortin-1 receptor locus (MC1R). Fourier analysis revealed that the medullary keratin matrix (spongy layer) of the feather barbs of blue males was ordered at the appropriate nanoscale to produce the observed blue colour by coherent light scattering. Surprisingly, the feather barbs of black males also contained a spongy layer that could produce a similar blue colour. However, black males had more melanin in their barbs than blue males, and this melanin may effectively mask any structural colour produced by the spongy layer. Moreover, the presence of this spongy layer suggests that black island males evolved from a blue-plumaged ancestor. We also document concordant patterns of variation at the MC1R locus, as five amino acid substitutions were perfectly associated with the divergent blue and black plumage phenotypes. Thus, with the possible involvement of a melanocortin receptor locus, increased melanin density may mask the blue-producing microstructure in black island males, resulting in the divergence of plumage coloration between mainland and island white-winged fairy-wrens. Such mechanisms may also be responsible for plumage colour diversity across broader geographical and evolutionary scales.
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Affiliation(s)
- S M Doucet
- Department of Biological Sciences, 331 Funchess Hall, Auburn University, Auburn, AL 36849, USA
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205
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Doucet SM, Mennill DJ, Montgomerie R, Boag PT, Ratcliffe LM. Achromatic plumage reflectance predicts reproductive success in male black-capped chickadees. Behav Ecol 2004. [DOI: 10.1093/beheco/arh154] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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206
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Schmidt V, Martin Schaefer H, Winkler H. Conspicuousness, not colour as foraging cue in plant-animal signalling. OIKOS 2004. [DOI: 10.1111/j.0030-1299.2004.12769.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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207
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Thomas RJ, Bartlett LA, Marples NM, Kelly DJ, Cuthill IC. Prey selection by wild birds can allow novel and conspicuous colour morphs to spread in prey populations. OIKOS 2004. [DOI: 10.1111/j.0030-1299.2004.13089.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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208
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Théry M, Debut M, Gomez D, Casas J. Specific color sensitivities of prey and predator explain camouflage in different visual systems. Behav Ecol 2004. [DOI: 10.1093/beheco/arh130] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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209
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Stuart-Fox DM, Moussalli A, Johnston GR, Owens IPF. EVOLUTION OF COLOR VARIATION IN DRAGON LIZARDS: QUANTITATIVE TESTS OF THE ROLE OF CRYPSIS AND LOCAL ADAPTATION. Evolution 2004; 58:1549-59. [PMID: 15341157 DOI: 10.1111/j.0014-3820.2004.tb01735.x] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Many animal species display striking color differences with respect to geographic location, sex, and body region. Traditional adaptive explanations for such complex patterns invoke an interaction between selection for conspicuous signals and natural selection for crypsis. Although there is now a substantial body of evidence supporting the role of sexual selection for signaling functions, quantitative studies of crypsis remain comparatively rare. Here, we combine objective measures of coloration with information on predator visual sensitivities to study the role of crypsis in the evolution of color variation in an Australian lizard species complex (Ctenophorus decresii). We apply a model that allows us to quantify crypsis in terms of the visual contrast of the lizards against their natural backgrounds, as perceived by potential avian predators. We then use these quantitative estimates of crypsis to answer the following questions. Are there significant differences in crypsis/conspicuousness among populations? Are there significant differences in crypsis conspicuousness between the sexes? Are body regions "exposed" to visual predators more cryptic than "hidden" body regions? Is there evidence for local adaptation with respect to crypsis against different substrates? In general, our results confirmed that there are real differences in crypsis/conspicuousness both between populations and between sexes; that exposed body regions were significantly more cryptic than hidden ones, particularly in females; and that females, but not males, are more cryptic against their own local background than against the background of other populations [corrected]. Body regions that varied most in contrast between the sexes and between populations were also most conspicuous and are emphasized by males during social and sexual signaling. However, results varied with respect to the aspect of coloration studied. Results based on chromatic contrast ("hue" of color) provided better support for the crypsis hypothesis than did results based on achromatic contrast ("brightness" of color). Taken together, these results support the view that crypsis plays a substantial role in the evolution of color variation and that color patterns represent a balance between the need for conspicuousness for signaling and the need for crypsis to avoid predation.
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Affiliation(s)
- Devi M Stuart-Fox
- Department of Zoology and Entomology, University of Queensland, St Lucia, Q 4072, Australia.
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210
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MASELLO JF, PAGNOSSIN ML, LUBJUHN T, QUILLFELDT P. Ornamental non-carotenoid red feathers of wild burrowing parrots. Ecol Res 2004. [DOI: 10.1111/j.1440-1703.2004.00653.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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211
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Göth A, Evans CS. Social responses without early experience: Australian brush-turkey chicks use specific visual cues to aggregate with conspecifics. J Exp Biol 2004; 207:2199-208. [PMID: 15159424 DOI: 10.1242/jeb.01008] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Almost all birds depend upon early experience with adults and siblings to learn recognition cues. Megapodes, such as the Australian brush-turkey(Alectura lathami), have evolved a very different life history. Eggs are incubated in mounds of decaying organic material. Chicks hatch asynchronously and receive no parental care, so imprinting cannot occur. Nevertheless, chicks subsequently form groups with similar-aged conspecifics. We explored the perceptual basis of this aggregation response, focussing on likely visual cues, such as pecking movements and body colour. Experiments were conducted under naturalistic conditions in a large aviary, using realistic robot models and colour filters. The robots successfully evoked a range of social responses resembling those of a live companion. Aggregation depended upon both behaviour and morphology. Simultaneous choice tests revealed that brush-turkey chicks preferred a pecking robot over either a static model or a scanning robot, suggesting that responsiveness depends upon particular movement patterns. In addition, chicks were sensitive to changes in appearance but only those that affected radiance at short wavelengths. The mechanism underlying social aggregation after hatching hence involves relatively specific cues. This perceptual bias seems to be largely experience independent and may exploit attributes to which potential predators are insensitive.
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Affiliation(s)
- Ann Göth
- Animal Behaviour Laboratory, Department of Psychology, Macquarie University, Sydney, NSW 2109, Australia.
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212
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Honkavaara J, Siitari H, Viitala J. Fruit Colour Preferences of Redwings (Turdus iliacus): Experiments with Hand-Raised Juveniles and Wild-Caught Adults. Ethology 2004. [DOI: 10.1111/j.1439-0310.2004.00980.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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213
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Cook LM. The rise and fall of the Carbonaria form of the peppered moth. QUARTERLY REVIEW OF BIOLOGY 2004; 78:399-417. [PMID: 14737825 DOI: 10.1086/378925] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The evidence for change in frequency of the melanic carbonaria morph in the peppered moth Biston betularia (L.) (Lepidoptera: Geometridae) in England and Wales is reviewed. At mid-20th century a steep cline of melanic phenotype frequency running from the north of Wales to the southern coast of England separated a region of 5% or less to west from 90% or more to northeast. By the 1980s the plateau of 90% frequency had contracted to northern England. The frequency has since continued to drop so that the maximum is now less than 50% and in most places below 10%. There have been similar declines in Europe and North America. Evidence from surveys and from two-point records shows the change to require 5% to 20% selection against the melanic. The melanic is more disadvantageous in regions where its frequency was initially high than in regions where it was low. Experiments to investigate predation by birds show a net advantage to carbonaria morphs in regions where typical frequencies were low at the time of the experiment, and a disadvantage where typical frequencies were high. This would be expected if environment and frequency were associated, and selective predation played a part in generating the association. The cryptic advantage of carbonaria was large in areas of heavy pollution where typical frequencies were 20% or less. The moth usually has a low density but is relatively highly mobile. The ability of present information to explain the patterns has been tested in simulations. They indicate a system under strong selection that has always been in a dynamic state without equilibria.
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Affiliation(s)
- Laurence M Cook
- Manchester Museum, University of Manchester, Manchester M13 9PL, United Kingdom.
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214
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Avilés JM, Soler JJ, Soler M, Møller AP. Rejection of parasitic eggs in relation to egg appearance in magpies. Anim Behav 2004. [DOI: 10.1016/j.anbehav.2003.08.022] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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215
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AVILÉS JESÚSM, MØLLER ANDERSP. How is host egg mimicry maintained in the cuckoo (Cuculus canorus)? Biol J Linn Soc Lond 2004. [DOI: 10.1111/j.1095-8312.2004.00311.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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216
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Bright A, Waas JR, King CM, Cuming PD. Bill colour and correlates of male quality in blackbirds: an analysis using canonical ordination. Behav Processes 2004; 65:123-32. [PMID: 15222961 DOI: 10.1016/j.beproc.2003.08.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2002] [Revised: 04/25/2003] [Accepted: 08/04/2003] [Indexed: 11/18/2022]
Abstract
Carotenoid-dependent plumage displays are widely assumed to be honest indicators of individual health or quality, which are used as cues during mate choice and/or agonistic signalling. Despite the fact that red, yellow and orange pigmentation of bills is common, and also variable between individuals, comparatively little is known about bill colouration as a condition-dependent trait. Furthermore, many studies of avian colouration are confounded by the lack of objective colour quantification and the use of overly simplistic univariate techniques for analysis of the relationship between the condition-dependent trait and individual quality variables. In this study, we correlated male blackbird bill colour (a likely carotenoid-dependent sexually selected trait) with body/condition variables that reflect male quality. We measured bill colour using photometric techniques, thus ensuring objectivity. The data were analysed using the multivariate statistical techniques of canonical ordination. Analyses based on reflectance spectra of male blackbird bill samples and colour components (i.e. hue, chroma and brightness) derived from the reflectance spectra were very similar. Analysing the entire reflectance spectra of blackbird bill samples with Redundancy Analysis (RDA) allowed examination of individual wavelengths and their specific associations with the body/condition variables. However, hue, chroma and brightness values also provided useful information to explain colour variation, and the two approaches may be complimentary. We did not find any significant associations between male blackbird bill colour and percent incidence of ectoparasites or cloaca size. However, both the colour component and full spectral analyses showed that culmen length explained a significant amount of variation in male blackbird bill colour. Culmen length was positively associated with greater reflectance from the bill samples at longer wavelengths and a higher hue value (i.e. more orange-pigmented bills). Larger males may have larger territories or be better at defending territories during male-male interactions, ensuring access to carotenoid food sources. Future studies should elucidate the relationship between bill colour and behavioural measures such as aggressiveness, territory size, song rate and nest attendance.
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Affiliation(s)
- A Bright
- Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton, New Zealand.
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217
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Doucet SM, Yezerinac SM, Montgomerie R. Do female zebra finches (Taeniopygia guttata) copy each other's mate preferences? CAN J ZOOL 2004. [DOI: 10.1139/z03-210] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated whether female zebra finches (Taeniopygia guttata) would alter their mate preferences after observing the choices of other females. Experimental trials consisted of four 30-min stages: (A) acclimation, (B) observer female chooses between two males, (C) observer female watches a model female interact with her nonpreferred male from stage B, and (D) observer female again chooses between the two males. Control trials were identical except that there was no model female in stage C. Females in both experimental and control trials spent significantly more time with the nonpreferred male in stage D than they had in stage B; thus, our experiment appeared to reveal no evidence of mate choice copying. There was, however, a significant positive relationship between the increase in the time that an observer female in experimental trials spent with her nonpreferred male in stage D and the number of interactions that she had previously observed between the model female and that male in stage C. A second experiment of similar design, where observer females were prevented from observing the model female and nonpreferred male interact in stage B, demonstrated that the behaviour of the observer female in the first experiment was not simply a response to changes in male behaviour in stage D. While our experiment does not support the hypothesis that female zebra finches copy each other's mate preferences, our findings suggest that public information may influence the behaviour of female zebra finches toward potential mates.
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218
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Stuart-Fox DM, Moussalli A, Johnston GR, Owens IPF. EVOLUTION OF COLOR VARIATION IN DRAGON LIZARDS: QUANTITATIVE TESTS OF THE ROLE OF CRYPSIS AND LOCAL ADAPTATION. Evolution 2004. [DOI: 10.1554/03-448] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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219
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Pearn SM, Bennett ATD, Cuthill IC. The Role of Ultraviolet-A Reflectance and Ultraviolet-A-Induced Fluorescence in Budgerigar Mate Choice. Ethology 2003. [DOI: 10.1046/j.0179-1613.2003.00936.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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220
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Conspicuous males suffer higher predation risk: visual modelling and experimental evidence from lizards. Anim Behav 2003. [DOI: 10.1006/anbe.2003.2235] [Citation(s) in RCA: 209] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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221
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Abstract
Although several bird species have been shown to reflect ultraviolet (UV) light from their plumages, the incidence of UV reflectance, and therefore the potential for UV or UV-enhanced signals, across the avian tree of life is not known. In this study, we collected reflectance data from the plumages of 312 bird species representing 142 families. Our results demonstrate that all avian families possess plumages that reflect significant amounts of UV light. The ubiquity of UV reflectance indicates that all studies of avian behaviour, ecology and evolution involving plumage coloration would benefit from consideration of plumage reflectance in the UV portion of the electromagnetic spectrum. Additionally, we demonstrate the existence of cryptic UV plumage patches and cryptic dimorphism among birds.
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Affiliation(s)
- Muir D Eaton
- Bell Museum of Natural History, University of Minnesota, St Paul, MN 55108, USA.
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222
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AVILES JESUSM, MØLLER ANDERSP. Meadow pipit (Anthus pratensis) egg appearance in cuckoo (Cuculus canorus) sympatric and allopatric populations. Biol J Linn Soc Lond 2003. [DOI: 10.1046/j.1095-8312.2003.00208.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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223
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SOLER JUANJ, AVILES JESUSM, SOLER MANUEL, MØLLER ANDERSP. Evolution of host egg mimicry in a brood parasite, the great spotted cuckoo. Biol J Linn Soc Lond 2003. [DOI: 10.1046/j.1095-8312.2003.00209.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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224
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Shawkey MD, Estes AM, Siefferman LM, Hill GE. Nanostructure predicts intraspecific variation in ultraviolet-blue plumage colour. Proc Biol Sci 2003; 270:1455-60. [PMID: 12965009 PMCID: PMC1691395 DOI: 10.1098/rspb.2003.2390] [Citation(s) in RCA: 161] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Evidence suggests that structural plumage colour can be an honest signal of individual quality, but the mechanisms responsible for the variation in expression of structural coloration within a species have not been identified. We used full-spectrum spectrometry and transmission electron microscopy to investigate the effect of variation in the nanostructure of the spongy layer on expression of structural ultraviolet (UV)-blue coloration in eastern bluebird (Sialia sialis) feathers. Fourier analysis revealed that feather nanostructure was highly organized but did not accurately predict variation in hue. Within the spongy layer of feather barbs, the number of circular keratin rods significantly predicted UV-violet chroma, whereas the standard error of the diameter of these rods significantly predicted spectral saturation. These observations show that the precision of nanostructural arrangement determines some colour variation in feathers.
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Affiliation(s)
- Matthew D Shawkey
- Department of Biological Sciences, Auburn University, 331 Funchess Hall, Auburn, AL 36849, USA.
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225
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Thomas RJ, Marples NM, Cuthill IC, Takahashi M, Gibson EA. Dietary conservatism may facilitate the initial evolution of aposematism. OIKOS 2003. [DOI: 10.1034/j.1600-0706.2003.12061.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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226
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Mennill DJ, Doucet SM, Montgomerie R, Ratcliffe LM. Achromatic color variation in black-capped chickadees, Poecile atricapilla: black and white signals of sex and rank. Behav Ecol Sociobiol 2003. [DOI: 10.1007/s00265-003-0581-8] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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227
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Abstract
Recent behavioural experiments have shown that birds use ultraviolet (UV)-reflective and fluorescent plumage as cues in mate choice. It remains controversial, however, whether such UV signals play a special role in sexual communication, or whether they are part of general plumage coloration. We use a comparative approach to test for a general association between sexual signalling and either UV-reflective or fluorescent plumage. Among the species surveyed, 72% have UV colours and there is a significant positive association between UV reflectance and courtship displays. Among parrots (Psittaciformes), 68% of surveyed species have fluorescent plumage, and again there is a strong positive association between courtship displays and fluorescence. These associations are not artefacts of the plumage used in courtship displays, being generally more 'colourful' because there is no association between display and colours lacking UV reflectance or fluorescence. Equally, these associations are not phylogenetic artefacts because all results remain unchanged when families or genera, rather than species, are used as independent data points. We also find that, in parrots, fluorescent plumage is usually found adjacent to UV-reflective plumage. Using a simple visual model to examine one parrot, the budgerigar Melopsittacus undulatus, we show that the juxtaposition of UV-reflective and fluorescent plumage leads to a 25-fold increase in chromatic contrast to the budgerigar's visual system. Taken together, these results suggest that signals based on UV contrast are of special importance in the context of active sexual displays. We review briefly six hypotheses on why this may be the case: suitability for short-range signalling; high contrast with backgrounds; invisibility to predators; exploitation of pre-existing sensory biases; advertisement of feather structure; and amplification of behavioural signals.
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Affiliation(s)
- Franziska Hausmann
- School of Environmental Sciences, Griffith University, Nathan, Brisbane, Q4111, Australia
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228
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McGraw KJ, Mackillop EA, Dale J, Hauber ME. Different colors reveal different information: how nutritional stress affects the expression of melanin- and structurally based ornamental plumage. J Exp Biol 2002; 205:3747-55. [PMID: 12409501 DOI: 10.1242/jeb.205.23.3747] [Citation(s) in RCA: 244] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Avian plumage colors have emerged recently as model systems for investigating the types of information that can be signaled by showy sexual displays in animals. In many species, the brightness of carotenoid-based plumage reflects the health and condition of individuals and is used in mate selection. The information contained in melanin-based and structurally based ornamental colors in birds is less well resolved, however. We subjected male house sparrows Passer domesticus and brown-headed cowbirds Molothrus ater to stressful nutritional conditions during molt to test the hypothesis that melanin- and structurally based plumage colors are nutritionally condition-dependent. We restricted food access for treatment males during randomized 6 h periods on 4 days per week, while allowing control birds access to food ad libitum throughout the course of the molt. We found that the size and brightness of the melanin-based throat badges in male house sparrows were not affected by nutritional stress. Similarly, there were no differences between treatment and control male cowbirds in the size or brightness of the melanin-based brown hood. However, the structurally based iridescent plumage of cowbirds was indicative of the nutritional condition of males during molt. Nutritionally stressed cowbirds grew significantly less colorful plumage than did males with access to food ad libitum. These results are consistent with observations in other avian species that different types of plumage color communicate different sets of information. Melanin ornaments are less sensitive to nutritional conditions during molt and instead may reflect the hormonal status and/or competitive ability of males, whereas structural coloration appears to be an accurate signal of health and condition.
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Affiliation(s)
- Kevin J McGraw
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA.
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229
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Greenwood VJ, Smith EL, Cuthill IC, Bennett AT, Goldsmith AR, Griffiths R. Do European starlings prefer light environments containing UV? Anim Behav 2002. [DOI: 10.1006/anbe.2002.1977] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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230
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Smith EL, Greenwood VJ, Bennett ATD. Ultraviolet colour perception in European starlings and Japanese quail. J Exp Biol 2002; 205:3299-306. [PMID: 12324539 DOI: 10.1242/jeb.205.21.3299] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYWhereas humans have three types of cone photoreceptor, birds have four types of single cones and, unlike humans, are sensitive to ultraviolet light(UV, 320-400 nm). Most birds are thought to have either a violet-sensitive single cone that has some sensitivity to UV wavelengths (for example, many non-passerine species) or a single cone that has maximum sensitivity to UV(for example, oscine passerine species). UV sensitivity is possible because,unlike humans, avian ocular media do not absorb UV light before it reaches the retina. The different single cone types and their sensitivity to UV light give birds the potential to discriminate reflectance spectra that look identical to humans. It is clear that birds use UV signals for a number of visual tasks,but there are few studies that directly demonstrate a role for UV in the detection of chromaticity differences (i.e. colour vision) as opposed to achromatic brightness. If the output of the violet/UV cone is used in achromatic visual tasks, objects reflecting more UV will appear brighter to the bird. If, however, the output is used in a chromatic mechanism, birds will be able to discriminate spectral stimuli according to the amount of reflected light in the UV part of the spectrum relative to longer wavelengths. We have developed a UV `colour blindness' test, which we have given to a passerine(European starling) and a non-passerine (Japanese quail) species. Both species learnt to discriminate between a longwave control of orange vs red stimuli and UV vs `non-UV' stimuli, which were designed to be impossible to differentiate by achromatic mechanisms. We therefore conclude that the output of the violet/UV cone is involved in a chromatic colour vision system in these two species.
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Affiliation(s)
- Emma L Smith
- Ecology of Vision Laboratory, School of Biological Sciences, University of Bristol, UK.
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231
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Rapid Behavioural Adjustments to Unfavourable Light Conditions in European Starlings ( Sturnus Vulgaris). Anim Welf 2002. [DOI: 10.1017/s0962728600024349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
AbstractAlthough it is known that many birds possess ultraviolet (UV)-sensitive vision, most commercially housed poultry species, as well as species held in zoos, laboratories, or bred for show, are maintained under lighting that is deficient in UV wavelengths compared with normal daylight. UV-sensitive vision has been shown to be important in both foraging and mate-choice decisions. UV-poor conditions, in which information in this waveband is eliminated, could, therefore, present an important welfare issue. Eight European starlings were given a series of preference tests (eight hours per trial, for six days), in which they could choose to feed in one of four channels. Four experimental trials were carried out, during which the channels were covered in either UV-transmitting (UV+) or UV-blocking (UV-) filters, to determine whether birds had an initial preference for feeding in UV-rich environments and whether there was any change in their preference over time. There was an initial preference for the UV+ environment, but this preference declined very rapidly with familiarity, and was absent by the final trial. These results imply that starlings can rapidly adjust their feeding behaviour if faced with unfamiliar light environments and that any initial behavioural changes attributable to UV-deficient environments may be short-lived. However, further work is necessary to establish whether these adjustments occur across a range of species and contexts before any welfare concerns can be ruled out.
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232
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Context-dependent visual preferences in starlings and blue tits: mate choice and light environment. Anim Behav 2002. [DOI: 10.1006/anbe.2001.1868] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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233
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234
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Shettleworth SJ, Westwood RP. Divided attention, memory, and spatial discrimination in food-storing and nonstoring birds, black-capped chickadees ( Poecile atricapilla) and dark-eyed Juncos ( Junco hyemalis). ACTA ACUST UNITED AC 2002. [DOI: 10.1037/0097-7403.28.3.227] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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235
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Maddocks SA, Goldsmith AR, Cuthill IC. The influence of flicker rate on plasma corticosterone levels of European starlings, Sturnus vulgaris. Gen Comp Endocrinol 2001; 124:315-20. [PMID: 11742515 DOI: 10.1006/gcen.2001.7718] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent reviews have highlighted the differences between human and avian vision with regard to temporal resolution and the potential problems it may cause for avian welfare and video playback experiments. Birds tend to have much higher critical fusion frequencies than do humans (>100 Hz vs 50-60 Hz in humans), which means that they perceive light as flickering up to and over 100 Hz. This is higher than most television monitors (which have refresh rates of 50 or 60 Hz) and normal fluorescent lighting (100 or 120 Hz), and because humans find flickering light aversive, it has been suggested that birds will as well. If this were the case, then there would be welfare implications of maintaining them under such lighting and also a potential effect on their behavioral responses in video playback experiments. However, there is some behavioral evidence that indicates that birds do not appear to find flicker aversive and may even prefer flickering lighting. The authors aimed to determine whether a passerine, the European starling, found flicker aversive by measuring the corticosterone stress response in birds maintained under high- or low-frequency fluorescent lighting (35-40 kHz vs 100 Hz) for 1 or 24 h. The results suggest that low-frequency lighting is potentially more stressful because, where differences exist, birds in the low-frequency treatment always showed higher basal corticosterone. However, the evidence is not consistent because in half of the blocks, there were no significant treatment effects and, where there were, the time course of the effects was variable.
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Affiliation(s)
- S A Maddocks
- Centre for Behavioural Biology, School of Biological Sciences, University of Bristol, Woodland Road, Bristol, BS8 1UG, United Kingdom
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236
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Pearn SM, Bennett AT, Cuthill IC. Ultraviolet vision, fluorescence and mate choice in a parrot, the budgerigar Melopsittacus undulatus. Proc Biol Sci 2001; 268:2273-9. [PMID: 11674876 PMCID: PMC1088876 DOI: 10.1098/rspb.2001.1813] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
As in many parrots, the plumage of the budgerigar Melopsittacus undulatus reflects near-ultraviolet (UVA) wavelengths (300-400 nm) and exhibits UVA-induced fluorescence. However, there have, to our knowledge, been no tests of whether the yellow fluorescence observed under intense UVA illumination has any role in signalling. Four experiments were carried out on wild-type budgerigars, where the presence and absence of UV reflectance and fluorescence were manipulated using filters. Few studies have attempted to separate the contribution of UV reflectance to plumage hue as opposed to brightness or distinguish between a role in sexual as opposed to social preferences. However, our first experiments show that not only do females consistently prefer UV-reflecting males, but also that the observed preferences are due to removal of UV affecting the perceived hue rather than brightness. Furthermore, we found no effect of the light environment on male response to females, suggesting that the female preferences relate to plumage colour per se. Whilst UV reflectance appears important in heterosexual choice by females, it has no detectable influence on same-sex association preferences. The results from the second series of experiments suggest that enhancement of the budgerigar's yellow coloration through fluorescence has no effect on male attractiveness. However, the fluorescent plumage may play a role in signalling by virtue of the fact that it absorbs UVA and so increases contrast with nearby UV-reflecting plumage. Our study provides convincing evidence that UV reflectances can play a role in mate choice in non-passerines, but no evidence that the yellow fluorescence observed under UVA illumination is itself important as a signal.
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Affiliation(s)
- S M Pearn
- Centre for Behavioural Biology, School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK.
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237
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Behavioural and physiological effects of absence of ultraviolet wavelengths for domestic chicks. Anim Behav 2001. [DOI: 10.1006/anbe.2001.1842] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Hunt S, Cuthill IC, Bennett AT, Church SC, Partridge JC. Is the ultraviolet waveband a special communication channel in avian mate choice? J Exp Biol 2001; 204:2499-507. [PMID: 11511665 DOI: 10.1242/jeb.204.14.2499] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYThere is growing evidence that ultraviolet (UV) wavelengths play an important role in avian mate choice. One of the first experiments to support this idea showed that female zebra finches (Taeniopygia guttata) prefer UV-reflecting males to males whose ultraviolet reflection has been removed. The effect was very strong despite little or no UV reflection from several plumage areas. However, it is not clear how the importance of the UV waveband compares to other regions of the bird-visible spectrum. We tested whether the response of female zebra finches to the removal of male UV reflection is greater than to the removal of other wavebands. We presented females with a choice of males whose appearance was manipulated using coloured filters. The filters removed single blocks of the avian visible spectrum corresponding closely to the spectral sensitivities of each of the zebra finch’s single cone classes. This resulted in males that effectively had no UV (UV−), no short-wave (SW−), no medium-wave (MW−) or no long-wave (LW−) plumage reflection. Females preferred UV− and SW− males. LW− and MW− males were least preferred, suggesting that female zebra finches show the greatest response to the removal of longer wavelengths. Quantal catches of the single cone types viewing body areas of the male zebra finch are presented for each treatment. Our study suggests it is important to consider the role of the UV waveband in avian mate choice in conjunction with the rest of the avian visible spectrum.
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Affiliation(s)
- S Hunt
- Centre for Behavioural Biology, School of Biological Sciences, University of Bristol, UK.
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240
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Maddocks SA, Church SC, Cuthill IC. The effects of the light environment on prey choice by zebra finches. J Exp Biol 2001; 204:2509-15. [PMID: 11511666 DOI: 10.1242/jeb.204.14.2509] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYRecent research has highlighted the extent to which birds utilise ultraviolet vision in mate choice and foraging. However, neither the importance of the ultraviolet compared with other regions of the visual spectrum nor the use of wavelength cues in other visual tasks have been explored. We assessed the individual choices of zebra finches (Taeniopygia guttata) for different-coloured seeds (red and white millet) under lighting conditions in which filters selectively removed blocks of the avian-visible spectrum corresponding to the spectral sensitivity of the four retinal cone types that subserve colour vision in this species. The effects corresponded to those predicted from the calculated distances between seed types, and between each seed type and the background, in a simple model of tetrachromatic colour space. As predicted for this foraging task, the removal of long-wavelength information had a greater influence than the removal of shorter wavelengths, including ultraviolet wavelengths. These results have important implications for predator–prey interactions and suggest that future studies of natural foraging should consider variations in the light environment.
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Affiliation(s)
- S A Maddocks
- Centre for Behavioural Biology and Ecology of Vision Group, School of Biological Sciences, Bristol, BS8 1UG, UK
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Church SC, Merrison AS, Chamberlain TM. Avian ultraviolet vision and frequency-dependent seed preferences. J Exp Biol 2001; 204:2491-8. [PMID: 11511664 DOI: 10.1242/jeb.204.14.2491] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYIt is well established that ultraviolet sensitivity plays an important role in the visually guided behaviour of birds. From a foraging perspective, evidence now exists that ultraviolet wavelengths are used by birds when foraging for insects, berries, seeds and mammals. Here, we present the results of two laboratory experiments that test the effect of removing (i) ultraviolet wavelengths and (ii) wavebands in the human-visible region on the frequency-dependent seed preferences of zebra finches (Taeniopygia guttata). Although the seeds and backgrounds used in our experiments reflected mainly at long wavelengths, we found that removal of ultraviolet wavelengths significantly changed the strength and direction of frequency dependence compared with full-spectrum illumination. We also found that the removal of ultraviolet wavelengths (300–400nm) did not affect the strength of frequency dependence compared with the removal of short wavelengths (approximately 400–500nm), medium wavelengths (approximately 500–600nm) or long wavelengths (approximately 600–700nm). Since frequency-dependent selection has direct consequences for the stability of prey populations and the spectral quality of ambient light is known to vary considerably with climate, time of day and local habitat geometry, our results suggest that ultraviolet wavelengths might play an important role in the dynamics of plant populations. However, we urge caution about overestimating the importance of ultraviolet wavelengths compared with wavelengths in the human-visible spectrum.
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Affiliation(s)
- S C Church
- Ecology of Vision Research Group, School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK.
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