The effect of experimental pollinator decline on pollinator-mediated selection on floral traits
Data files
Mar 19, 2024 version files 144.38 KB
Abstract
Human-mediated environmental change, by reducing mean fitness, is hypothesized to strengthen selection on traits that mediate interactions among species. For example, human-mediated declines in pollinator populations are hypothesized to reduce mean seed production by increasing the magnitude of pollen limitation and thus strengthen pollinator-mediated selection on floral traits that increase pollinator attraction or pollen transfer efficiency. To test this hypothesis, we measured two female fitness components and six floral traits of Lobelia siphilitica plants exposed to supplemental hand-pollination, ambient open-pollination, or reduced open-pollination treatments. The reduced treatment simulated pollinator decline, while the supplemental treatment was used to estimate pollen limitation and pollinator-mediated selection. We found that plants in the reduced pollination treatment were significantly pollen-limited, resulting in pollinator-mediated selection for taller inflorescences and more vibrant petals, both traits that could increase pollinator attraction. This contrasts with plants in the ambient pollination treatment, where reproduction was not pollen-limited and there was no significant pollinator-mediated selection on any floral trait. Our results support the hypothesis that human-mediated environmental change can strengthen the selection on traits of interacting species and suggest that these traits have the potential to evolve in response to changing environments.
README: The effect of experimental pollinator decline on pollinator-mediated selection on floral traits
https://doi.org/10.5061/dryad.h70rxwdqh
Description of the data and file structure
This package contains 4 data files:
“Raw Data for Ecology and Evolution Submission.xlsx”
This file contains the raw (i.e. not relativized or standardized) data used for all analyses in the manuscript. The columns are as follows:
- Treatment: Hand = Supplemental hand pollination; Open = Ambient open pollination; Redu = Reduced open pollination
- Plant_ID: Unique number identifying each plant included in the data set
- Fruits_Per_Plant: Number of fruits produced by each plant
- Seeds_Per_Plant: Number of seeds produced by each plant
- Inflorescence_Height: Height of the inflorescence in cm
- Daily_Display: Mean number of open flowers on a plant per day
- Petal_Brightness: Index of the reflectance of the petals across all wavelengths
- Petal_Chroma: Index of the amount of grey light mixed in with the primary petal hue
- Projected_Area: Area of the three fused lower petal lobes (i.e. the lower lip) and two fused upper petal lobes (i.e. the upper lip) in cm2
- Corolla_Length: The length of the corolla tube in cm
- Field_Site: Identity of the field site where each experimental plant was located (A, B, C, or D)
“mean.floral.fitness.csv”
A .csv version of the raw data file (described above).
“fpp.rel.stand.csv”
The file used to estimate phenotypic selection via fruits per plant.
- Treatment: Hand = Supplemental hand pollination; Open = Ambient open pollination; Redu = Reduced open pollination
- Plant: Unique number identifying each plant included in the data set
- rel.fpp: Number of fruits produced by each plant, relativized within each treatment by dividing by mean fitness.
- field.site: Identity of the field site where each experimental plant was located (A, B, C, or D)
- stand.height: Height of the inflorescence in cm, standardized within each treatment to a mean of 0 and a variance of 1 (z-transformation)
- stand.display: Mean number of open flowers on a plant per day, standardized within each treatment to a mean of 0 and a variance of 1 (z-transformation)
- stand.brightness: Index of the reflectance of the petals across all wavelengths, standardized within each treatment to a mean of 0 and a variance of 1 (z-transformation)
- stand.chroma: Index of the amount of grey light mixed in with the primary petal hue, standardized within each treatment to a mean of 0 and a variance of 1 (z-transformation)
- stand.projected: Area of the three fused lower petal lobes (i.e. the lower lip) and two fused upper petal lobes (i.e. the upper lip) in cm2, standardized within each treatment to a mean of 0 and a variance of 1 (z-transformation)
- stand.area: The length of the corolla tube in cm, standardized within each treatment to a mean of 0 and a variance of 1 (z-transformation)
“spp.rel.stand.csv”
The file used to estimate phenotypic selection via seeds per plant.
- Treatment: Hand = Supplemental hand pollination; Open = Ambient open pollination; Redu = Reduced open pollination
- Plant: Unique number identifying each plant included in the data set
- rel.spp: Number of seeds produced by each plant, relativized within each treatment by dividing by mean fitness.
- field.site: Identity of the field site where each experimental plant was located (A, B, C, or D)
- stand.height: Height of the inflorescence in cm, standardized within each treatment to a mean of 0 and a variance of 1 (z-transformation)
- stand.display: Mean number of open flowers on a plant per day, standardized within each treatment to a mean of 0 and a variance of 1 (z-transformation)
- stand.brightness: Index of the reflectance of the petals across all wavelengths, standardized within each treatment to a mean of 0 and a variance of 1 (z-transformation)
- stand.chroma: Index of the amount of grey light mixed in with the primary petal hue, standardized within each treatment to a mean of 0 and a variance of 1 (z-transformation)
- stand.projected: Area of the three fused lower petal lobes (i.e. the lower lip) and two fused upper petal lobes (i.e. the upper lip) in cm2, standardized within each treatment to a mean of 0 and a variance of 1 (z-transformation)
- stand.area: The length of the corolla tube in cm, standardized within each treatment to a mean of 0 and a variance of 1 (z-transformation)
Code/Software
Script.R: the R script to recreate the analyses presented in the manuscript