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Extravagant ornaments are thought to signal male quality to females choosing mates, but the evidence linking ornament size to male quality is controversial, particularly in cases in which females prefer different ornaments in different populations. Here, we use whole-genome sequencing and transcriptomics to determine the genetic basis of ornament size in two populations of a widespread warbler, the common yellowthroat ( Geothlypis trichas ). Within a single subspecies, females in a Wisconsin population prefer males with larger black masks as mates, while females in a New York population prefer males with larger yellow bibs. Despite being produced by different pigments in different patches on the body, the size of the ornament preferred by females in each population was linked to numerous genes that function in many of the same core aspects of male quality (e.g., immunity and oxidative balance). These relationships confirm recent hypotheses linking the signaling function of ornaments to male quality. Furthermore, the parallelism in signaling function provides the flexibility for different types of ornaments to be used as signals of similar aspects of male quality. This could facilitate switches in female preference for different ornaments, a potentially important step in the early stages of divergence among populations.
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This content will become publicly available on April 12, 2026
Loss of pigments in females is associated with sexual dichromatism in an ornamental trait
Abstract Sexual dichromatism is thought to evolve primarily as a function of sexual selection, especially female choice. However, other forces, from sex-specific environmental conditions to social signaling in females, can also generate color differences between sexes. We studied dewlap dichromatism across 292 species of Anolis lizards. Dewlaps are colorful throat ornaments found on males of most anole species but are also present in females in many species. Although male and female dewlaps often have similar coloration, in some species, they are strikingly dichromatic. We found that ornament color is labile and that dichromatism results from the loss of costly pigments in females. This pattern could indicate a shift towards signal loss in females; however, the secondary gains of female dewlaps across the phylogeny suggest a potential advantageous function. Possible mechanisms for female dewlap coloration include social selection, nonsexual signaling, or detectability in different microhabitats (e.g., sensory drive). Female dewlap color overlap between co-occurring species is both less than expected by chance overall and reduced in species-rich communities, suggesting that dichromatism could be driven by competition. Our results highlight that selection on females drives the observed pattern of dichromatism, suggesting a potentially adaptive role for female ornaments and emphasizing the need for additional work to understand female ornament evolution.
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- Award ID(s):
- 1542534
- PAR ID:
- 10601269
- Editor(s):
- Parins-Fukuchi, Tomomi; Connallon, Tim
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Evolution
- ISSN:
- 0014-3820
- Subject(s) / Keyword(s):
- Anolis anole dewlap macroevolution comparative biology sexual dimorphism
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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