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Foster, but not genetic, father plumage coloration has a temperature-dependent effect on offspring quality

journal contribution
posted on 2023-06-09, 15:46 authored by P E Järvistö, S Calhim, Wiebke SchuettWiebke Schuett, W Velmala, T Laaksonen
Secondary sexual characters have most likely evolved through sexual selection because such traits indicate the genetic or phenotypic quality of the bearer. While genetic variation in such fitness-related traits should be depleted by directional selection, there are many cases in which variation is higher than expected. One hypothesis explaining this variation is that different phenotypes within a population are adapted to different environmental conditions. We tested this hypothesis by comparing the offspring quality of male pied flycatchers, Ficedula hypoleuca, with different degrees of melanin-based dorsal plumage coloration under different environmental conditions. To create different environmental growth conditions and to be able to separate offspring genotype effects from paternal effects on offspring body mass, we used a partial cross-foster design where the brood size was reduced or enlarged by one chick. We also examined the interactive effects of temperature and male phenotype because previous correlative studies suggest such temperature-dependent effects in this species. We show that, while manipulated brood size did not interact with male phenotype to affect offspring quality, temperature during the nestling period influenced the offspring quality of dark and brown foster (but not genetic) fathers. When the temperature was relatively low during the nestling period, foster offspring of black males were lighter than those raised by brown males; the opposite was true if temperature was relatively high. These results add a new aspect to our understanding of how variation in the degree of melanin-based coloration is maintained in wild populations and how phenotypic variation may be maintained in general.


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Behavioral Ecology and Sociobiology









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  • Evolution, Behaviour and Environment Publications

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