Egg pigmentation reflects female and egg quality in the Spotless starling Sturnus unicolor.
Fecha
2008
Autores
Título de la revista
ISSN de la revista
Título del volumen
Editor
Springer
Resumen
It has been proposed that blue colouration in
eggs has evolved as a signal of female quality that males
can use to modulate their parental investment. This
hypothesis is based in the antioxidant properties of
biliverdin whose costly deposition in the eggshell is
expected to signal female antioxidant capacity and egg
quality. Since maternally derived androgens are costly to
produce and may adaptively affect offspring phenotype,
high-quality females may benefit by signalling their
androgen investment through egg colouration. Our aim
was to investigate whether egg colour variation in the
spotless starling reflected the amount of pigments on the
eggshell and whether egg pigmentation was related to
female and egg quality. Chromatography analyses revealed
that spotless starling eggshells contained two different
pigments: biliverdin and protoporphyrin IX with no
correlation between them. Biliverdin contents correlated
positively with egg colouration indicating that darker eggs
with a higher peak in the blue–green segment of the
spectrum contained higher amounts of biliverdin. Eggs
containing more biliverdin were laid by high-quality
females and contained higher yolk testosterone levels.
However, despite the strong correlation between biliverdin
and colorimetric variables, egg colouration did not reflect
accurately female and egg quality. Our results provide
evidence that eggshell pigmentation in the spotless starling
is related to female and egg quality as shown by the yolk
testosterone levels. However, the lack of relation between
egg colour and female condition and egg quality do not
provide evidence to support the signalling function of egg
colouration.
Descripción
Palabras clave
Citación
Egg pigmentation reflects female and egg quality in the Spotless starling Sturnus unicolor. Behavioural Ecology and Sociobiology 62: 1877-1884.