title: Condition-dependent expression of melanin-based coloration in the Eurasian kestrel.
abstract: Melanin is the most common pigment in animal integuments and is responsible for some of the most striking ornaments. A central tenet of sexual selection theory states that melanin-based traits can signal absolute individual quality in any environment only if their expression is condition-dependent. Significant costs imposed by an ornament would ensure that only the highest quality individuals display the most exaggerated forms of the signal. Firm evidence that melanin-based traits can be condition-dependent is still rare in birds. In an experimental test of this central assumption, we report condition-dependent expression of a melanin-based trait in the Eurasian kestrel (Falco tinnunculus). We manipulated nestling body condition by reducing or increasing the number of nestlings soon after hatching. A few days before fledging, we measured the width of sub-terminal black bands on the tail feathers. Compared to nestlings from enlarged broods, individuals raised in reduced broods were in better condition and thereby developed larger sub-terminal bands. Furthermore, in 2 years, first-born nestlings also developed larger sub-terminal bands than their younger siblings that are in poorer condition. This demonstrates that expression of melanin-based traits can be condition-dependent.
authors.affiliation: Department of Ecology and Evolution, Biophore, University of Lausanne, 1015, Lausanne, Switzerland.
authors.forename: Romain
authors.initials: R
authors.lastname: Piault
authors.forename: Valentijn
authors.initials: V
authors.lastname: van den Brink
authors.forename: Alexandre
authors.initials: A
authors.lastname: Roulin
mesh_terms: D000818:Animals; D052284:Clutch Size; D046093:Falconiformes / Q000378:metabolism / Q000502:physiology*; D005260:Female; D016014:Linear Models; D008297:Male; D008543:Melanins / Q000378:metabolism*; D010858:Pigmentation / Q000502:physiology*; D012727:Sex Characteristics; D012867:Skin / Q000378:metabolism
chemical_list: D008543:Melanins