Data from: Model selection analysis of temporal variation in benefit for an ant-tended treehopper
Data files
Sep 16, 2021 version files 935.72 KB
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0304.nlme.analysis.1.R
87.26 KB
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0304.nlme.analysis.10.R
87.44 KB
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0304.nlme.analysis.2.R
87.30 KB
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0304.nlme.analysis.3.R
87.17 KB
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0304.nlme.analysis.4.R
87.30 KB
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0304.nlme.analysis.5.R
87.17 KB
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0304.nlme.analysis.6.R
87.30 KB
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0304.nlme.analysis.7.R
87.17 KB
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0304.nlme.analysis.8.R
87.04 KB
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0304.nlme.analysis.9.R
87.31 KB
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0304.nlme.analysis.base.R
5.62 KB
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data.0304.csv
34.38 KB
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data.0304.Rdata
8.55 KB
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models.csv
2.34 KB
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results.0304.nlme.R
12.38 KB
Abstract
Recent studies of mutualism have emphasized both that the net benefit to participants depends on the ecological context and that the density‐dependent pattern of benefit is key to understanding the population dynamics of mutualism. Indeed, changes in the ecological context are likely to drive changes in both the magnitude of benefit and the density‐dependent pattern of benefit. Despite the close linkage between these two areas of research, however, few studies have addressed the factors underlying variation in the density‐dependent pattern of benefit. Here I use model selection to evaluate how variation in the benefits of a mutualism drives temporal variation in the density‐dependent pattern of net benefit for the ant‐tended treehopper Publilia concava. In the interaction between ants and treehoppers in the genus Publilia, ants collect the sugary excretions of treehoppers as a food resource, and treehoppers benefit both directly (e.g., by feeding facilitation) and indirectly (e.g., by predator protection). Results presented here show that temporal changes in the relative magnitude of direct and indirect benefit components of ant tending, especially the effectiveness of predator protection by ants, qualitatively change the overall pattern of density‐dependent benefit between years with maximum benefit shifting from treehoppers in small to large aggregations. These results emphasize the need for empirical studies that evaluate the long‐term dynamics of mutualism and theoretical studies that consider the population dynamics consequences of variation in the density‐dependent pattern of benefit.
Usage notes
File | Description |
data.0304.csv | Data in comma separated value format |
data.0304.Rdata | Data in R binary format |
0304.nlme.analysis.R | Script to generate 2003-04 results in Table 1 |
results.0304.nlme.R | Script to generate results in Table 1, Figures 1-5, and Appendix A1 |
0304.nlme.analysis.[1-10].R | Scripts called by results.0304.nlme.R that fit the models listed in the file models.csv for 10 different start values |
models.csv | Comma separated value file that contains the model name and number of parameters |
For the underlying data in the data.* files, column labels are as follows:
census - Census interval: early (1 = censuses 1-2) or late (2 = censuses 2-3)
year - 2003 or 2004
census.year - unique combination of year and census
grid - blocking variable
plant - unique plant and year identifier
ant.trt - ant manipulation treatment: 0 = ant exclusion, 1 = control
T0 - The number of the treehoppers at time t=0 (i.e. either census 1 or census 2)
T1 - The number of treehoppers at time t+1 (i.e. either census 2 or census 3)
ants - average number of ants observed on plant
species - ant species: Note that in Table 2, C.n. corresponds to c, F."f." to ff, F."n." to fl, F."p." to fs, M. to m, "P.i." to p and T.s. to t
p - Dummy variable associated with step function for ant-protection, redundant with ant.trt
dC - Dummy variable associated with census
dY - Dummy variable associated with year
apm - ants divided by T0