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

Autor: Taysom AJ; Department of Zoology, University of Melbourne, Melbourne, Vic., Australia., Stuart-Fox D, Cardoso GC
Jazyk: angličtina
Zdroj: Journal of evolutionary biology [J Evol Biol] 2011 Feb; Vol. 24 (2), pp. 303-13. Date of Electronic Publication: 2010 Nov 04.
DOI: 10.1111/j.1420-9101.2010.02166.x
Abstrakt: 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.
(© 2010 The Authors. Journal of Evolutionary Biology © 2010 European Society For Evolutionary Biology.)
Databáze: MEDLINE
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