10.5061/DRYAD.P69N4
Ruiz-Rodriguez, Magdalena
Spanish National Research Council
Tomás, Gustavo
Spanish National Research Council
Martín-Gálvez, David
Spanish National Research Council
Ruiz-Castellano, Cristina
Spanish National Research Council
Soler, Juan
Spanish National Research Council
Data from: Bacteria and the evolution of honest signals. The case of
ornamental throat feathers in spotless starlings
Dryad
dataset
2015
Uropygial gland
Feather-degrading bacteria
Bacillus licheniformis
ornaments
Sturnus unicolor
Bacterial load
2015-10-31T00:00:00Z
2015-10-31T00:00:00Z
en
https://doi.org/10.1111/1365-2435.12376
44883 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
1.Mechanisms guaranteeing reliability of messages are essential in
understanding the underlying information and evolution of signals.
Microorganisms may degrade signalling traits and therefore, influence the
transmitted information and evolution of these characters. The role of
microorganisms in animal signalling has, however, rarely been
investigated. 2.Here, we explore a possible role for feather-degrading
bacteria driving the design of ornamental throat feathers in male spotless
starlings (Sturnus unicolor). We estimated length, bacterial load,
degradation status, and susceptibility to degradation by keratinolytic
bacteria in those feathers, compared to non-ornamental adjacent feathers
in males, as well as to throat feathers in females. In addition, the
volume of the uropygial gland and its secretion was measured, and the
secretion extracted. We also experimentally evaluated the capacity of each
secretion to inhibit growth of a keratinolytic bacterium. 3.The apical
part of male ornamental throat feathers harboured more bacteria and
degraded more quickly than the basal part; these patterns were not
detected in female throat feathers or in non-ornamental male feathers.
Moreover, degradation status of male and female throat feathers did not
differ, but was positively associated with feather bacterial density.
Finally, the size of the uropygial gland in both males and females
predicted volume and the inhibitory capacity of secretion against
feather-degrading bacteria. Only in males was uropygial gland size
negatively associated with the level of feather degradation. 4.All results
indicate differential susceptibility of different parts of throat feathers
to keratinolytic bacterial attack, which supports the possibility that
throat feathers in starlings reflect individual ability to combat
feather-degrading bacteria honestly. This is further supported by the
relationship detected between antimicrobial properties of uropygial
secretion and the level of feather degradation. 5.Our results suggest that
selection pressures exerted by feather-degrading bacteria on hosts may
promote evolution of particular morphologies of secondary sexual traits
with different susceptibility to bacterial degradation that reliably
inform of their bacterial load. Those results will help to understand the
evolution of ornamental signals.
MetadataDataset used in this manuscript: results of the experiment and
field measures. Abbreviations: 0, 120, 480 h (weight): concentration of
oligopeptides at 0, 120 and 480 hours of the experiment. Data are
corrected by the weight of each feather
piece.metadata_RuizRodriguezetal.pdf
Southeastern Spain