Down feather morphology reflects adaptation to habitat and thermal conditions across the avian phylogeny
| Main Authors: | Pap, Peter Laszlo, Osváth, Gergely, Daubner, Timea, Nord, Andreas, Vincze, Orsolya |
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| Format: | info dataset eJournal |
| Terbitan: |
, 2020
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| Online Access: |
https://zenodo.org/record/3997854 |
Daftar Isi:
- Down feathers are the first feather types that appear in both the phylogenetic and the ontogenetic history of birds. Although it is widely acknowledged that the primary function of downy elements is insulation, little is known about the interspecific variability in the structural morphology of these feathers, and the environmental factors that have influenced their evolution. Here, we collected samples of down and afterfeathers from 156 bird species and measured key morphological characters that define the insulatory properties of the downy layer. We then tested if habitat and climatic conditions could explain the observed between-species variation in down feather structure. We show that habitat has a very strong and clearly defined effect on down feather morphology. Feather size, barbule length and nodus density all decreased from terrestrial towards aquatic birds, with riparian species exhibiting intermediate characters. Wintering climate, expressed as windchill (a combined measure of the ambient temperature and wind speed) had limited effects on down morphology, colder climate only being associated with higher nodus density in dorsal down feathers. Overall, an aquatic lifestyle selects for a denser plumulaceous layer, while the effect of harsh wintering conditions on downy structures appear limited. These results provide key evidence of adaptations to habitat at the level of the downy layer, both on the scale of macro- and micro-elements of the plumage. Moreover, they reveal characters of convergent evolution in the avian plumage and mammalian fur, that match the varying needs of insulation in terrestrial and aquatic modes of life.
- All important information is included in the Methods. Funding provided by: János Bolyai Research Scholarship*Crossref Funder Registry ID: Award Number: Funding provided by: Swedish Research Council*Crossref Funder Registry ID: Award Number: 637-2013-7442Funding provided by: Birgit and Hellmuth Hertz Foundation / The Royal Physiographic Society of Lund*Crossref Funder Registry ID: Award Number: 2017-39034Funding provided by: Universitatea Babeș-BolyaiCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100006347Award Number: 36957/2017Funding provided by: János Bolyai Research ScholarshipCrossref Funder Registry ID: Funding provided by: Swedish Research CouncilCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100004359Award Number: 637-2013-7442Funding provided by: Birgit and Hellmuth Hertz Foundation / The Royal Physiographic Society of LundCrossref Funder Registry ID: Award Number: 2017-39034
- Feathers were collected from dead birds and from a museum collection. Feathers were photographed and feather traits were measured from pictures using a software. For further details see the Methods.