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The contribution of structural-, psittacofulvin- and melanin-based colouration to sexual dichromatism in Australasian parrots

Taysom, Alice Jo and Stuart-Fox, D and Cardoso, J. C (2011) The contribution of structural-, psittacofulvin- and melanin-based colouration to sexual dichromatism in Australasian parrots. Journal Of Evolutionary Biology, 24 (2). pp. 303-313. ISSN 1420-9101

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Abstract

Colour ornamentation in animals is exceptionally diverse, but some colours may provide better signals of individual quality or more efficient visual stimuli and, thus, be more often used as sexual signals. This may depend on physiological costs, which depend on the mechanism of colour production (e.g. exogenously acquired colouration in passerine birds appears to be most sexually dichromatic). We studied sexual dichromatism in a sample of 27 Australasian parrot species with pigment- (melanin and psittacofulvin) and structural-based colouration, to test whether some of these types of colouration are more prominent in sexual ornamentation. Unlike passerines, in which long wavelength colouration (yellow to red) usually involves exogenous and costly carotenoid pigments, yellow to red colouration in parrots is based on endogenously synthesized psittacofulvin pigments. This allows us to assess whether costly exogenous pigments are necessary for these plumage colours to have a prominent role in sexual signalling. Structural blue colouration showed the largest and most consistent sexual dichromatism, both in area and perceptually relevant chromatic differences, indicating that it is often ornamental in parrots. By contrast, we found little evidence for consistent sexual dichromatism in melanin-based colouration. Unlike passerines, yellow to red colouration was not strongly sexually dichromatic: although the area of colouration was generally larger in males, colour differences between the sexes were on average imperceptible to parrots. This is consistent with the idea that the prominent yellow to red sexual dichromatism in passerines is related to the use of carotenoid pigments, rather than resulting from sensory bias for these colours.

Item Type: Article
Uncontrolled Keywords: colour ornamentation, pigment colours, sexual dichromatism, sexual selection, structural colour, colour traits, carotenoid, antioxidant, sexual signalling, handicap hypothesis, signal efficacy hypothesis
Subjects: FOR Classification > 0608 Zoology
Faculty/School/Research Centre/Department > School of Engineering and Science
Depositing User: VUIR
Date Deposited: 04 Jun 2013 01:43
Last Modified: 04 Jun 2013 01:43
URI: http://vuir.vu.edu.au/id/eprint/21796
DOI: 10.1111/j.1420-9101.2010.02166.x
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Citations in Scopus: 2 - View on Scopus

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