September 1, 2001The American Naturalist
Plumage Color as a Composite Trait: Developmental and Functional Integration of Sexual Ornamentation
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Discussion
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Implication
Longitudinal study uncovers divergent viability and fecundity selection on individual components of male house finch plumage, indicating sexual ornaments evolve as composite signals.
Key Points
- To examine whether carotenoid-based plumage functions as a composite sexual ornament with distinct developmental pathways and fitness consequences for its individual components.
- Tracked 498 male house finches (Carpodacus mexicanus) across multiple selection episodes over 5 years in a Montana population.
- Quantified four individual ornament components: pigment elaboration, patch area, pigment symmetry, and patch area symmetry.
- Evaluated the separate fitness impacts of each ornament component under both fecundity and viability selection.
- Fecundity selection favored increased redness (pigment elaboration) and reduced asymmetry in both pigment and patch area, but did not act on overall patch area.
- Viability selection favored larger and more symmetrical feather patches, with no detectable selection acting on pigment elaboration.
- Plumage components exhibited partial developmental independence, with functional interrelationships differing between house finch populations.
Cite This Study
Badyaev et al. (2001) studied this question.