The Evolution of bird plumage colouration: a role for feather-degradation bacteria?

Abstract

[ENG] Aims: To test the existence of differences in the effects in vitro of a feather-degrading bacteria on bird feat-
\nhers containing different types of pigments, and thus, of different colours.
\nMethods: Tubes containing feathers from nine bird species and containing three different pigments or no pig-
\nments were inoculated with bacteria (Bacillus licheniformis isolated from soil) and incubated at 37°C during
\neight days. Feather damage was monitored daily.
\nResults and Conclusions: At the end of the experiment nearly all feathers were degraded to dust or fibres.
\nHowever, melanin-containing feathers suffered from earlier bacterial damage than carotenoid-containing fe-
\nathers or unpigmented feathers. The feathers last showing signs of bacterial damage were those of a parake-
\net that contained an unknown green pigment. The pigmentation of a feather, and thus its colour, may deter-
\nmine its susceptibility to bacterial degradation. Therefore if feather degrading bacteria could grow on
\nfree-ranging birds, they could play an unsuspected role on the evolution of bird plumage colouration