Open AccessOn silver wings: a fragile structural mechanism increases plumage conspicuousness
Author(s) -
Galván Ismael,
Negro Juan J.,
Bortolotti Gary R.,
Margalida Antoni
Publication year - 2009
Publication title -
journal of avian biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.022
H-Index - 76
eISSN - 1600-048X
pISSN - 0908-8857
DOI - 10.1111/j.1600-048x.2009.04820.x
Subject(s) - plumage , iridescence , feather , biology , dorsum , mechanism (biology) , wing , reflectivity , zoology , evolutionary biology , ecology , optics , anatomy , physics , quantum mechanics , thermodynamics
We report for the first time the existence of a structural mechanism of feathers different from iridescence that makes plumage conspicuous. By using electron and light microscopy, we show that the mechanism consists of special lengthened and twisted distal barbules that are very susceptible to damage. The dorsal side of these barbules is translucent, which creates a distinctive sheen colouration to feathers that otherwise would be dark. When distal sheen barbules are broken, the black proximal barbules are exposed, thus generating a conspicuous difference between abraded and non‐abraded areas. Total and ultraviolet reflectance of sheen (non‐abraded) areas are strikingly higher than in abraded areas. We propose that this mechanism represents a case of convergent evolution in species that are limited in developing colourful plumage patches. Future studies should explore the potential of this colour mechanism to act as a signal of individual quality or identity.