Authors: Juan Manuel PeraltaSánchez Juan José Soler Antonio Manuel MartínPlatero Rob Knight Manuel MartínezBueno Anders Pape Møller
Publish Date: 2013/12/07
Volume: 67, Issue: 2, Pages: 480-487
Abstract
The use of feathers to line bird’s nests has traditionally been interpreted as having a thermoregulatory function Featherdegrading bacteria growing on feathers lining nests may have antimicrobial properties which may provide an additional benefit to lining nests with feathers We test the hypothesis that the production of antimicrobial substances by feather bacteria affects the microbiological environment of the nest and therefore the bacterial density on eggshells and indirectly hatching success These effects would be expected to differ between nests lined with pigmented and white feathers because bacteria grow differently on feathers of different colors We experimentally manipulated the composition of pigmented and unpigmented feathers in nests of the barn swallow Hirundo rustica and studied the antimicrobial properties against the keratindegrading bacterium Bacillus licheniformis of bacteria isolated from feathers of each color Analyzed feathers were collected at the end of the incubation period and antimicrobial activity was defined as the proportion of bacteria from the feathers that produce antibacterial substances effective against B licheniformis Our experimental manipulation affected antimicrobial activity which was higher in nests with only white feathers at the beginning of incubation Moreover white feathers showed higher antimicrobial activity than black ones Interestingly antimicrobial activity in feathers of one of the colors correlated negatively with bacterial density on feather of the opposite color Finally antimicrobial activity of white feathers was negatively related to eggshell bacterial load These results suggest that antimicrobial properties of feathers in general and of white feathers in particular affect the bacterial environment in nests This environment in turn affects the bacterial load on eggshells which may affect hatching successWe thank E LopezHernández for technical assistance and Einar FlenstenJenssen for providing accommodation and interesting discussions during fieldwork We appreciate the comments by three anonymous referees that improved the quality of the manuscript This study was funded by Ministerio de Ciencia e Innovación/FEDER project CGL200761251/BOS and CGL201019233C0301 and Junta de Andalucía project P09RNM4557 JMPS was funded by Ministerio de Educación and Consejería de Innovación Ciencia y Empresa under International Excellence Campus Program CEI Granada RK was supported in part by the Howard Hughes Medical Institute
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