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Composition of Bacterial Assemblages in Different Components of Reed Warbler Nests and a Possible Role of Egg Incubation in Pathogen Regulation.

Brandl HB, van Dongen WF, Darolová A, Krištofík J, Majtan J, Hoi H - PLoS ONE (2014)

Bottom Line: We found that bacterial assemblages clustered by nest component.Overall, our study appears to be the first to demonstrate differences in bacterial assemblages between bird nest components.In addition, we highlight the complexity of nest bacterial assemblages and provide new insights into the benefits of incubation.

View Article: PubMed Central - PubMed

Affiliation: Konrad Lorenz Institute of Ethology, Department of Integrative Biology and Evolution, University of Veterinary Medicine Vienna, Savoyenstrasse 1a, 1160 Vienna, Austria.

ABSTRACT
Bacteria play a central role in animal health. Yet, little is known about the acquisition of bacteria and the extent to which bacteria are acquired from different environmental sources. For example, bird nests host diverse bacteria associated with the eggs, nestlings and nesting material, but previous research has typically focussed on only a limited number of nest components at a time. It therefore remains unknown to what extent bacteria are transmitted between these components. Using both molecular and culture techniques, we characterised nest-associated bacterial assemblages throughout the entire nesting cycle of reed warblers by sampling bacteria on eggs before and during incubation, within nestling faeces, and on the nesting material of post-breeding nests. We found that bacterial assemblages clustered by nest component. Yet some overlap existed between nest components, suggesting that bacterial transmission across components is likely to occur. Eggs and nestlings from the same nest harboured more similar bacteria than expected by chance, suggesting an influence of environment or genetics on bacterial assemblages. Bacterial loads were not lower on incubated eggs. Instead, incubation was associated with a change in the structure of assemblages, including a decrease in potentially-harmful Gram-negative bacteria. In addition we show for the first time, that incubation is associated with the complete extinction of harmful haemolytic bacteria. Overall, our study appears to be the first to demonstrate differences in bacterial assemblages between bird nest components. In addition, we highlight the complexity of nest bacterial assemblages and provide new insights into the benefits of incubation.

No MeSH data available.


Related in: MedlinePlus

Differences in bacterial assemblages between the nest components.Non-metric multi-dimensional scaling along A) the first and second axis, B) the second and third axis and C) the first and third axis, displaying differences in bacterial assemblages between the four nest components including preincubation eggs (closed circles and dash dot line), incubated eggs (open circles and long dashed line), nestling faeces (closed triangles and dotted line) and nesting material (open diamonds and a solid line).
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pone-0114861-g001: Differences in bacterial assemblages between the nest components.Non-metric multi-dimensional scaling along A) the first and second axis, B) the second and third axis and C) the first and third axis, displaying differences in bacterial assemblages between the four nest components including preincubation eggs (closed circles and dash dot line), incubated eggs (open circles and long dashed line), nestling faeces (closed triangles and dotted line) and nesting material (open diamonds and a solid line).

Mentions: Bacterial assemblages sampled from preincubation eggs of the same nest tended to be more similar to each other than expected by chance (observed similarity sum: 249.4; expected similarity sum: 198.8±13.2; N = 8; p = 0.069). Similarly, within-nest similarity of bacterial assemblages sampled from nestling faeces was greater than inter-nest assemblage similarity (observed similarity sum: 217.8; expected similarity sum: 168.7±7.3; N = 9; p = 0.011). The nMDS revealed pronounced differences in the structure of bacterial assemblages between the four different nest components. The stress of the two-dimensional analysis was 0.26, suggesting that the variation in the data could not be reliably captured in two dimensions. The stress of the three-dimensional analysis was acceptable (stress = 0.19). We found strong clustering of assemblages by nest component. Despite the close proximity of nesting material with the nestlings, we found rather little overlap in their bacterial assemblages (Fig. 1, Table 2). In contrast, we detected a strong overlap in the assemblages on eggs before and during incubation (S2 Figure). The multivariate dispersion indices indicated that intersample variation in assemblage structure was lowest in the nesting material samples (multivariate dispersion index = 0.77). Assemblages on eggs sampled before and during incubation displayed much higher variability (multivariate dispersion indices = 1.13 and 0.96 respectively), similar to the variability found in the assemblages in nestling faeces (multivariate dispersion indices = 1.1).


Composition of Bacterial Assemblages in Different Components of Reed Warbler Nests and a Possible Role of Egg Incubation in Pathogen Regulation.

Brandl HB, van Dongen WF, Darolová A, Krištofík J, Majtan J, Hoi H - PLoS ONE (2014)

Differences in bacterial assemblages between the nest components.Non-metric multi-dimensional scaling along A) the first and second axis, B) the second and third axis and C) the first and third axis, displaying differences in bacterial assemblages between the four nest components including preincubation eggs (closed circles and dash dot line), incubated eggs (open circles and long dashed line), nestling faeces (closed triangles and dotted line) and nesting material (open diamonds and a solid line).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4262450&req=5

pone-0114861-g001: Differences in bacterial assemblages between the nest components.Non-metric multi-dimensional scaling along A) the first and second axis, B) the second and third axis and C) the first and third axis, displaying differences in bacterial assemblages between the four nest components including preincubation eggs (closed circles and dash dot line), incubated eggs (open circles and long dashed line), nestling faeces (closed triangles and dotted line) and nesting material (open diamonds and a solid line).
Mentions: Bacterial assemblages sampled from preincubation eggs of the same nest tended to be more similar to each other than expected by chance (observed similarity sum: 249.4; expected similarity sum: 198.8±13.2; N = 8; p = 0.069). Similarly, within-nest similarity of bacterial assemblages sampled from nestling faeces was greater than inter-nest assemblage similarity (observed similarity sum: 217.8; expected similarity sum: 168.7±7.3; N = 9; p = 0.011). The nMDS revealed pronounced differences in the structure of bacterial assemblages between the four different nest components. The stress of the two-dimensional analysis was 0.26, suggesting that the variation in the data could not be reliably captured in two dimensions. The stress of the three-dimensional analysis was acceptable (stress = 0.19). We found strong clustering of assemblages by nest component. Despite the close proximity of nesting material with the nestlings, we found rather little overlap in their bacterial assemblages (Fig. 1, Table 2). In contrast, we detected a strong overlap in the assemblages on eggs before and during incubation (S2 Figure). The multivariate dispersion indices indicated that intersample variation in assemblage structure was lowest in the nesting material samples (multivariate dispersion index = 0.77). Assemblages on eggs sampled before and during incubation displayed much higher variability (multivariate dispersion indices = 1.13 and 0.96 respectively), similar to the variability found in the assemblages in nestling faeces (multivariate dispersion indices = 1.1).

Bottom Line: We found that bacterial assemblages clustered by nest component.Overall, our study appears to be the first to demonstrate differences in bacterial assemblages between bird nest components.In addition, we highlight the complexity of nest bacterial assemblages and provide new insights into the benefits of incubation.

View Article: PubMed Central - PubMed

Affiliation: Konrad Lorenz Institute of Ethology, Department of Integrative Biology and Evolution, University of Veterinary Medicine Vienna, Savoyenstrasse 1a, 1160 Vienna, Austria.

ABSTRACT
Bacteria play a central role in animal health. Yet, little is known about the acquisition of bacteria and the extent to which bacteria are acquired from different environmental sources. For example, bird nests host diverse bacteria associated with the eggs, nestlings and nesting material, but previous research has typically focussed on only a limited number of nest components at a time. It therefore remains unknown to what extent bacteria are transmitted between these components. Using both molecular and culture techniques, we characterised nest-associated bacterial assemblages throughout the entire nesting cycle of reed warblers by sampling bacteria on eggs before and during incubation, within nestling faeces, and on the nesting material of post-breeding nests. We found that bacterial assemblages clustered by nest component. Yet some overlap existed between nest components, suggesting that bacterial transmission across components is likely to occur. Eggs and nestlings from the same nest harboured more similar bacteria than expected by chance, suggesting an influence of environment or genetics on bacterial assemblages. Bacterial loads were not lower on incubated eggs. Instead, incubation was associated with a change in the structure of assemblages, including a decrease in potentially-harmful Gram-negative bacteria. In addition we show for the first time, that incubation is associated with the complete extinction of harmful haemolytic bacteria. Overall, our study appears to be the first to demonstrate differences in bacterial assemblages between bird nest components. In addition, we highlight the complexity of nest bacterial assemblages and provide new insights into the benefits of incubation.

No MeSH data available.


Related in: MedlinePlus