Limits...
Sexual dimorphism in melanin pigmentation, feather coloration and its heritability in the barn swallow (Hirundo rustica).

Saino N, Romano M, Rubolini D, Teplitsky C, Ambrosini R, Caprioli M, Canova L, Wakamatsu K - PLoS ONE (2013)

Bottom Line: The relative concentration of either melanin (Pheo:Eu) differed between sexes in throat but not in belly feathers, and the concentrations in males compared to females were larger in belly than in throat feathers.Finally, we found high heritability of color of throat feathers.Melanization was found to differ from that recorded in Hirundo rustica rustica from Scotland or from H. r. erythrogaster from North America.

View Article: PubMed Central - PubMed

Affiliation: Department of Biosciences, University of Milan, Milan, Italy. nicola.saino@unimi.it

ABSTRACT
Melanin is the main pigment in animal coloration and considerable variation in the concentrations of the two melanin forms (pheo- and eumlanin) in pigmented tissues exists among populations and individuals. Melanin-based coloration is receiving increasing attention particularly in socio-sexual communication contexts because the melanocortin system has been hypothesized to provide a mechanistic basis for covariation between coloration and fitness traits. However, with few notable exceptions, little detailed information is available on inter-individual and inter-population variation in melanin pigmentation and on its environmental, genetic and ontogenetic components. Here, we investigate melanin-based coloration in an Italian population of a passerine bird, the barn swallow (Hirundo rustica rustica), its sex- and age-related variation, and heritability. The concentrations of eu- and pheomelanin in the throat (brown) and belly (white-to-brownish) feathers differed between sexes but not according to age. The relative concentration of either melanin (Pheo:Eu) differed between sexes in throat but not in belly feathers, and the concentrations in males compared to females were larger in belly than in throat feathers. There were weak correlations between the concentrations of melanins within as well as among plumage regions. Coloration of belly feathers was predicted by the concentration of both melanins whereas coloration of throat feathers was only predicted by pheomelanin in females. In addition, Pheo:Eu predicted coloration of throat feathers in females and that of belly feathers in males. Finally, we found high heritability of color of throat feathers. Melanization was found to differ from that recorded in Hirundo rustica rustica from Scotland or from H. r. erythrogaster from North America. Hence, present results show that pigmentation strategies vary in a complex manner according to sex and plumage region, and also among geographical populations, potentially reflecting adaptation to different natural and sexual selection regimes, and that some coloration components seem to be highly heritable.

Show MeSH

Related in: MedlinePlus

Relationship between offspring and the midparent ϑ and φ hue coloration components.Phenotypic values were normalized to a within-year mean of 0 to control for among-years sources of variation (see also Methods).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3585210&req=5

pone-0058024-g005: Relationship between offspring and the midparent ϑ and φ hue coloration components.Phenotypic values were normalized to a within-year mean of 0 to control for among-years sources of variation (see also Methods).

Mentions: We had information on both parents and an offspring for 34 families: 23 with a biological offspring and 11 with an EPO. The slope of the relationship between biological offspring and midparent phenotypic values was significant for θ and φ but not for rA (Table 5; Fig. 5), giving heritability estimates of 0.81±0.28 and 0.80±0.23 for θ and φ respectively. Several lines of evidence suggest that what we detect is heritability. First, there were no significant relationships between EPO phenotypic values and the phenotypic value of the social father, although for rA the coefficient was surprisingly high (Table 5). Second, heritability estimates based on offspring-mother relation were not stronger than those from offspring-midparent relation, suggesting absence of detectable maternal effects. Finally, for θ, the offspring phenotype was more tightly related to the average of parents phenotype than to either of the biological parents, suggesting additivity. This was not the case for φ, which showed some stronger relation between biological father and son than between mother or midparent and offspring, suggesting some potential sex-specific effects.


Sexual dimorphism in melanin pigmentation, feather coloration and its heritability in the barn swallow (Hirundo rustica).

Saino N, Romano M, Rubolini D, Teplitsky C, Ambrosini R, Caprioli M, Canova L, Wakamatsu K - PLoS ONE (2013)

Relationship between offspring and the midparent ϑ and φ hue coloration components.Phenotypic values were normalized to a within-year mean of 0 to control for among-years sources of variation (see also Methods).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585210&req=5

pone-0058024-g005: Relationship between offspring and the midparent ϑ and φ hue coloration components.Phenotypic values were normalized to a within-year mean of 0 to control for among-years sources of variation (see also Methods).
Mentions: We had information on both parents and an offspring for 34 families: 23 with a biological offspring and 11 with an EPO. The slope of the relationship between biological offspring and midparent phenotypic values was significant for θ and φ but not for rA (Table 5; Fig. 5), giving heritability estimates of 0.81±0.28 and 0.80±0.23 for θ and φ respectively. Several lines of evidence suggest that what we detect is heritability. First, there were no significant relationships between EPO phenotypic values and the phenotypic value of the social father, although for rA the coefficient was surprisingly high (Table 5). Second, heritability estimates based on offspring-mother relation were not stronger than those from offspring-midparent relation, suggesting absence of detectable maternal effects. Finally, for θ, the offspring phenotype was more tightly related to the average of parents phenotype than to either of the biological parents, suggesting additivity. This was not the case for φ, which showed some stronger relation between biological father and son than between mother or midparent and offspring, suggesting some potential sex-specific effects.

Bottom Line: The relative concentration of either melanin (Pheo:Eu) differed between sexes in throat but not in belly feathers, and the concentrations in males compared to females were larger in belly than in throat feathers.Finally, we found high heritability of color of throat feathers.Melanization was found to differ from that recorded in Hirundo rustica rustica from Scotland or from H. r. erythrogaster from North America.

View Article: PubMed Central - PubMed

Affiliation: Department of Biosciences, University of Milan, Milan, Italy. nicola.saino@unimi.it

ABSTRACT
Melanin is the main pigment in animal coloration and considerable variation in the concentrations of the two melanin forms (pheo- and eumlanin) in pigmented tissues exists among populations and individuals. Melanin-based coloration is receiving increasing attention particularly in socio-sexual communication contexts because the melanocortin system has been hypothesized to provide a mechanistic basis for covariation between coloration and fitness traits. However, with few notable exceptions, little detailed information is available on inter-individual and inter-population variation in melanin pigmentation and on its environmental, genetic and ontogenetic components. Here, we investigate melanin-based coloration in an Italian population of a passerine bird, the barn swallow (Hirundo rustica rustica), its sex- and age-related variation, and heritability. The concentrations of eu- and pheomelanin in the throat (brown) and belly (white-to-brownish) feathers differed between sexes but not according to age. The relative concentration of either melanin (Pheo:Eu) differed between sexes in throat but not in belly feathers, and the concentrations in males compared to females were larger in belly than in throat feathers. There were weak correlations between the concentrations of melanins within as well as among plumage regions. Coloration of belly feathers was predicted by the concentration of both melanins whereas coloration of throat feathers was only predicted by pheomelanin in females. In addition, Pheo:Eu predicted coloration of throat feathers in females and that of belly feathers in males. Finally, we found high heritability of color of throat feathers. Melanization was found to differ from that recorded in Hirundo rustica rustica from Scotland or from H. r. erythrogaster from North America. Hence, present results show that pigmentation strategies vary in a complex manner according to sex and plumage region, and also among geographical populations, potentially reflecting adaptation to different natural and sexual selection regimes, and that some coloration components seem to be highly heritable.

Show MeSH
Related in: MedlinePlus