Blue-green sexual dichormatism in tanagers (Family Thraupidae)

BARREIRA, A.; LIJTMAER, D. A.; LOUGHEED, S. C.; TUBARO, P. L.

Veracruz, México

Congreso; IV North American Ornithological Conference; 2006

AOU

The sexual dichromatism pattern that involves the presence of plumage patches that are bluish on males and greenish on females is recurrent among Tanagers. We studied plumage coloration through reflectance spectrophotometry on 8 species belonging to the genera _Dacnis_, _Tersina_, _Cyanerpes_, _Tangara_ and _Conirostrum_ with the intention of performing a more detailed analysis of this pattern. In general, males were brighter and had higher UV reflectance than females. We also detected 3 general reflectance patterns: 1) females with a single reflectance peak at middle wavelengths and males with also a single peak, but at short wavelengths; 2) females with a single reflectance peak at middle wavelengths and males with one reflectance peak at middle wavelengths and a secondary one at short wavelengths; and 3) females and males with a reflectance maximum at middle wavelengths and a secondary peak at short wavelengths. Therefore, even though this blue-green sexual dichromatism pattern seems to be superficially similar between species, the variability we found on the reflectance spectra suggest the existence of different color production mechanisms and should be considered in future studies of plumage evolution.