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Where is the extended phenotype in the wild? The community composition of arthropods on mature oak trees does not depend on the oak genotype.

Gossner MM, Brändle M, Brandl R, Bail J, Müller J, Opgenoorth L - PLoS ONE (2015)

Bottom Line: Our results suggest that spatial processes override the genetic effects of the host plant in structuring arthropod communities on oak trees.Because we used neutral markers, we cannot exclude the possibility that trait-specific markers may reveal a genetic imprint of the foundation tree species on the composition of the arthropod community.Future whole-genome studies are required to draw a final conclusion.

View Article: PubMed Central - PubMed

Affiliation: Terrestrial Ecology Research Group, Department of Ecology and Ecosystem Management, Technische Universität München, Hans-Carl-von-Carlowitz-Platz 2, 85354 Freising, Germany.

ABSTRACT
Through a series of common garden experiments, it has been shown that heritable phenotypic differences between individual trees can affect arthropod communities. However, field studies under heterogeneous environmental conditions remain rare. In the present study, we investigated the genetic constitution of 121 mature oak host trees at different trophic levels from 10 sites across Bavaria, southern Germany and their associated insect communities. A total of 23,576 individuals representing 395 species of beetles and true bugs were evaluated. In particular, we determined whether the composition of arthropod communities is related to the oak genotype and whether the strength of the relationships decreases from lower to higher trophic levels, such as for phytophagous, xylophagous, zoophagous, and mycetophagous species. The genetic differentiation of oaks was assessed using eight microsatellite markers. We found no significant influence of the oak genotype on neither the full beetle and true bug community nor on any of the analyzed trophic guilds. In contrast, the community composition of the insects was highly related to the space and climate, such that the community similarity decreased with increases in spatial distance and climatic differences. The relationship with space and climate was much stronger in beetles than in true bugs, particularly in mycetophagous species. Our results suggest that spatial processes override the genetic effects of the host plant in structuring arthropod communities on oak trees. Because we used neutral markers, we cannot exclude the possibility that trait-specific markers may reveal a genetic imprint of the foundation tree species on the composition of the arthropod community. However, based on the strength of the spatial patterns in our data set, we assume that genetic differences among oaks are less important in the structuring of arthropod communities. Future whole-genome studies are required to draw a final conclusion.

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Related in: MedlinePlus

Community similarity of true bugs, beetles and oaks vs. geographicdistance.Correlogram of the community similarity of beetles, true bugs, and oaks as afunction of distance (in km). This correlogram is interpreted as Moran’sI.
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pone.0115733.g004: Community similarity of true bugs, beetles and oaks vs. geographicdistance.Correlogram of the community similarity of beetles, true bugs, and oaks as afunction of distance (in km). This correlogram is interpreted as Moran’sI.

Mentions: The results of the PCA of the bioclim variables showed that the eigenvalues of thefirst four components contributed 94% to the correlations. Thus, for the subsequentanalyses, a Euclidian distance matrix was built using these four components. Thespace and climate were highly correlated with each other (Table 2) and had significanteffects on the arthropod community compositions. The effect was strongest in beetles,in which 30% and 24% of the variance was explained by the climate and space,respectively. In true bugs, only 16% and 6% of the variance was explained by theclimate and space, respectively. Among the beetle guilds, the variance in thecommunity assemblages was best explained for phytophages (21%, 10%), followed bymycetophages (13%, 22%), zoophages (7%, 8%) and xylophages (7%, 5%). In true bugs,climate explained 10% of the phytophagous and zoophagous assemblages, and spaceexplained 5% and 3% of these assemblages, respectively. The effects of climate andspace on the community composition were lower but still significant after correctingfor the other in the partial Mantel test. The analysis of the spatial autocorrelationshowed a significant positive spatial autocorrelation at spatial scales of up to 20km for true bugs and oak genetics and up to 30 km for beetles (Fig. 4).


Where is the extended phenotype in the wild? The community composition of arthropods on mature oak trees does not depend on the oak genotype.

Gossner MM, Brändle M, Brandl R, Bail J, Müller J, Opgenoorth L - PLoS ONE (2015)

Community similarity of true bugs, beetles and oaks vs. geographicdistance.Correlogram of the community similarity of beetles, true bugs, and oaks as afunction of distance (in km). This correlogram is interpreted as Moran’sI.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4321774&req=5

pone.0115733.g004: Community similarity of true bugs, beetles and oaks vs. geographicdistance.Correlogram of the community similarity of beetles, true bugs, and oaks as afunction of distance (in km). This correlogram is interpreted as Moran’sI.
Mentions: The results of the PCA of the bioclim variables showed that the eigenvalues of thefirst four components contributed 94% to the correlations. Thus, for the subsequentanalyses, a Euclidian distance matrix was built using these four components. Thespace and climate were highly correlated with each other (Table 2) and had significanteffects on the arthropod community compositions. The effect was strongest in beetles,in which 30% and 24% of the variance was explained by the climate and space,respectively. In true bugs, only 16% and 6% of the variance was explained by theclimate and space, respectively. Among the beetle guilds, the variance in thecommunity assemblages was best explained for phytophages (21%, 10%), followed bymycetophages (13%, 22%), zoophages (7%, 8%) and xylophages (7%, 5%). In true bugs,climate explained 10% of the phytophagous and zoophagous assemblages, and spaceexplained 5% and 3% of these assemblages, respectively. The effects of climate andspace on the community composition were lower but still significant after correctingfor the other in the partial Mantel test. The analysis of the spatial autocorrelationshowed a significant positive spatial autocorrelation at spatial scales of up to 20km for true bugs and oak genetics and up to 30 km for beetles (Fig. 4).

Bottom Line: Our results suggest that spatial processes override the genetic effects of the host plant in structuring arthropod communities on oak trees.Because we used neutral markers, we cannot exclude the possibility that trait-specific markers may reveal a genetic imprint of the foundation tree species on the composition of the arthropod community.Future whole-genome studies are required to draw a final conclusion.

View Article: PubMed Central - PubMed

Affiliation: Terrestrial Ecology Research Group, Department of Ecology and Ecosystem Management, Technische Universität München, Hans-Carl-von-Carlowitz-Platz 2, 85354 Freising, Germany.

ABSTRACT
Through a series of common garden experiments, it has been shown that heritable phenotypic differences between individual trees can affect arthropod communities. However, field studies under heterogeneous environmental conditions remain rare. In the present study, we investigated the genetic constitution of 121 mature oak host trees at different trophic levels from 10 sites across Bavaria, southern Germany and their associated insect communities. A total of 23,576 individuals representing 395 species of beetles and true bugs were evaluated. In particular, we determined whether the composition of arthropod communities is related to the oak genotype and whether the strength of the relationships decreases from lower to higher trophic levels, such as for phytophagous, xylophagous, zoophagous, and mycetophagous species. The genetic differentiation of oaks was assessed using eight microsatellite markers. We found no significant influence of the oak genotype on neither the full beetle and true bug community nor on any of the analyzed trophic guilds. In contrast, the community composition of the insects was highly related to the space and climate, such that the community similarity decreased with increases in spatial distance and climatic differences. The relationship with space and climate was much stronger in beetles than in true bugs, particularly in mycetophagous species. Our results suggest that spatial processes override the genetic effects of the host plant in structuring arthropod communities on oak trees. Because we used neutral markers, we cannot exclude the possibility that trait-specific markers may reveal a genetic imprint of the foundation tree species on the composition of the arthropod community. However, based on the strength of the spatial patterns in our data set, we assume that genetic differences among oaks are less important in the structuring of arthropod communities. Future whole-genome studies are required to draw a final conclusion.

Show MeSH
Related in: MedlinePlus