Fluorescent and ultraviolet sexual dichromatism in the blue-winged parrotlet

BARREIRA, A. S., LAGORIO, M. G, LIJTMAER, D. A., LOUGHEED, S. C, AND TUBARO, P. L.

JOURNAL OF ZOOLOGY (1987)

WILEY-BLACKWELL PUBLISHING, INC

Año: 2012 p. 135 - 142

0952-8369

The presence of sexual differences in plumage coloration (sexual dichromatism) isfrequent in birds. However, in many cases, humans cannot detect colour differencesthat are discernible to birds and it is therefore necessary to employ objectivemethods that contemplate the characteristics of the avian visual system for thestudy of plumage coloration. An understudied property of feather coloration isthe occurrence of fluorescence, which has been described almost exclusively inparrots from the Eastern Hemisphere using non-objective methods and has beenattributed to yellow pigments that are only present in psittacids. In this study, weexplore fluorescence and sexual dichromatism through objective and quantitativemethods in the plumage of a Neotropical species, the blue-winged parrotlet Forpusxanthopterygius. We measured plumage reflectance and fluorescence emission onmuseum skins using spectrophotometry and spectrofluorometry, respectively. Thereflectance analysis revealed the presence of ultraviolet sexual dichromatism thatadds to the differences in the visible range of wavelengths that are detectable byhumans. The spectrofluorometric analysis showed that fluorescence is indeedpresent in this species, both in green plumage patches, where fluorescent pigmentsare presumably located, and in the blue rump of males, where colour is consideredto be purely structurally based. The sexes differed in the intensity and wavelengthof their fluorescence emission, representing the first finding of fluorescence sexualdichromatism in birds.