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Lifetime Fitness Variation Across the Geographical Range in a Colour Polymorphic Species
Gian Luigi Bucciolini1,2, Chiara Morosinotto2,3,4,5, Jon Brommer1
1Department of Biology University of Turku Turku Finland.
Ecology and Evolution
|April 28, 2025
Summary
Evolutionary paradoxes are resolved by studying tawny owl (Strix aluco) populations. Disruptive selection on plumage color in tawny owls maintains heritable variation, explaining how selection doesn
Area of Science:
- Evolutionary Biology
- Ornithology
- Genetics
Background:
- Maintaining heritable trait variation under selection is an evolutionary paradox.
- Selection typically favors the fittest phenotype, potentially eroding variation.
- Plumage color variation in tawny owls (Strix aluco) presents a case study for this paradox.
Purpose of the Study:
- To investigate the maintenance of heritable variation in life-history traits in color-polymorphic tawny owls.
- To determine if plumage color influences reproductive success across different populations.
- To identify the selective pressures maintaining color polymorphism in tawny owls.
Main Methods:
- Longitudinal study of five European tawny owl populations over 13 years.
- Analysis of heritable plumage color variation (grey to brown-red).
- Quantification of life-history traits: breeding lifespan (BLS), lifetime egg production (LEP), lifetime reproductive success (LRS), and years skipped (NYS).
Main Results:
- Life-history traits varied significantly between study populations.
- Lifetime egg production (LEP) and lifetime reproductive success (LRS) showed population-specific variation across color morphs.
- Grey morph females exhibited higher LEP and LRS than brown-red morph females in some populations, and vice versa in others.
Conclusions:
- Disruptive selection on tawny owl plumage coloration is evident across their European range.
- This disruptive selection likely acts as a key factor in maintaining heritable color variation in tawny owls.
- The findings contribute to understanding the evolutionary mechanisms behind persistent phenotypic diversity.
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