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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.

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Mean (+ SE) concentration of eumelanin (PTCA) or pheomelanin (4-AHP) at two plumage regions of adult male and female barn swallows in two age classes (yearlings or older individuals).Because no age related variation existed, the sex-specific data pooled over the two age classes are also presented. Asterisks indicate a significant difference (P<0.05) between the sexes (see Table 1). Numbers in the body of the upper left figure are sample sizes of the sex by age classes.
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pone-0058024-g002: Mean (+ SE) concentration of eumelanin (PTCA) or pheomelanin (4-AHP) at two plumage regions of adult male and female barn swallows in two age classes (yearlings or older individuals).Because no age related variation existed, the sex-specific data pooled over the two age classes are also presented. Asterisks indicate a significant difference (P<0.05) between the sexes (see Table 1). Numbers in the body of the upper left figure are sample sizes of the sex by age classes.

Mentions: The mean concentrations of PTCA and 4-AHP, which are proportional to absolute concentrations of eu- or, respectively, pheomelanin in throat and belly feathers are visualized in Figure 2 and age- and sex-related variation is analyzed in linear models in Table 1.


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)

Mean (+ SE) concentration of eumelanin (PTCA) or pheomelanin (4-AHP) at two plumage regions of adult male and female barn swallows in two age classes (yearlings or older individuals).Because no age related variation existed, the sex-specific data pooled over the two age classes are also presented. Asterisks indicate a significant difference (P<0.05) between the sexes (see Table 1). Numbers in the body of the upper left figure are sample sizes of the sex by age classes.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0058024-g002: Mean (+ SE) concentration of eumelanin (PTCA) or pheomelanin (4-AHP) at two plumage regions of adult male and female barn swallows in two age classes (yearlings or older individuals).Because no age related variation existed, the sex-specific data pooled over the two age classes are also presented. Asterisks indicate a significant difference (P<0.05) between the sexes (see Table 1). Numbers in the body of the upper left figure are sample sizes of the sex by age classes.
Mentions: The mean concentrations of PTCA and 4-AHP, which are proportional to absolute concentrations of eu- or, respectively, pheomelanin in throat and belly feathers are visualized in Figure 2 and age- and sex-related variation is analyzed in linear models in Table 1.

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