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ABSTRACT Expression of vibrant plumage color plays important communication roles in many avian clades, ranging from penguins to passerines, but comparatively less is known about color signals in parrots (order Psittaciformes). We measured variation in coloration from three plumage patches (red face, blue rump, red tail) in an introduced population of rosy‐faced lovebirds (Agapornis roseicollis) in Phoenix, Arizona, USA and examined color differences between the sexes and ages as well as relationships with several indices of quality, including disease presence/absence (infection with beak and feather disease,Circovirus parrot, and a polyomavirus,Gammapolyomavirus avis), nutritional state (e.g., blood glucose and ketone levels), and habitat type from which birds were captured. We found that different plumage colors were linked to different quality indices: (a) adults had redder faces than juveniles, and birds with brighter faces had lower glucose levels and were less likely to have polyomavirus; (b) males had bluer rumps than females; and (c) birds caught farther from the city had redder and darker tail feathers than those caught closer to the urban center. Our findings reveal diverse information underlying variation in the expression of these disparate, ornate feather traits in an introduced parrot species, and suggest that these condition‐dependent and/or sexually dichromatic features may serve important intraspecific signaling roles (i.e., mediating rival competitions or mate choices).
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Complex plumages spur rapid color diversification in kingfishers (Aves: Alcedinidae)
Birds are among the most colorful animals on Earth. The different patterns and colors displayed on their feathers help them to identify their own species, attract mates or hide from predators. The bright plumages of birds are achieved through either pigments (such as reds and yellows) or structures (such as blues, greens or ultraviolet) inside feathers, or through a combination of both pigments and structures. Variation in the diversity of color patterns over time can give a helpful insight into the rate of evolution of a species. For example, structural colors evolve more quickly than pigment-based ones and can therefore be a key feature involved in species recognition or mate attraction. Studying the evolution of plumage patterns has been challenging due to differences in the vision of humans and birds. However, recent advances in technology have enabled researchers to map the exact wavelengths of the colors that make up the patterns, allowing for rigorous comparison of plumage color patterns across different individuals and species. To gain a greater understanding of how plumage color patterns evolve in birds, Eliason et al. studied kingfishers, a group of birds known for their complex and variable color patterns, and their worldwide distribution. The experiments analyzed the plumage color patterns of 72 kingfisher species (142 individual museum specimens) from both mainland and island populations by quantifying the amount of different wavelengths of light reflecting from a feather and accounting for relationships among species and among feather patches. The analyzes showed that having more complex patterns leads to a greater accumulation of plumage colors over time, supporting the idea that complex plumages provide more traits for natural or sexual selection to act upon. Moreover, in upper parts of the bodies, such as the back, the plumage varied more across the different species and evolved faster than in ventral parts, such as the belly or throat. This indicates that sexual selection may be the evolutionary force driving variation in more visible areas, such as the back, while patterns in the ventral part of the body are more important for kin recognition. Eliason et al. further found no differences in plumage complexity between kingfishers located in island or mainland habitats, suggesting that the isolation of the island and the different selection pressures this may bring does not impact the complexity of color patterns. However, kingfisher species located on islands did display higher rates of color evolution. This indicates that, regardless of the complexity of the plumage, island-specific pressures are driving rapid color diversification. Using a new multivariate approach, Eliason et al. have unearthed a pattern in plumage complexity that may otherwise have been missed and, for the first time, have linked differences in color pattern on individual birds with evolutionary differences across species. In doing so, they have provided a framework for future studies of color evolution. The next steps in this research would be to better understand why the island species are evolving more rapidly even though they do not have more complex plumage patterns and how the observed color differences relate to rapid rates of speciation.
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- Award ID(s):
- 2112467
- PAR ID:
- 10420516
- Date Published:
- Journal Name:
- eLife
- Volume:
- 12
- ISSN:
- 2050-084X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.7554/eLife.83426
