Selection favors high spread and asymmetry of flower opening dates within plant individuals
Data files
Jun 05, 2024 version files 1.03 MB
Abstract
Natural selection on traits expressed repeatedly by individuals is usually investigated with a focus on mean values, although within-individual trait distributions often differ also in other aspects, such as their spread and shape. In plants producing multiple flowers during a season, there might not be a single optimal flowering time, but rather an optimal distribution of flower opening dates. This optimal distribution might depend on both resource allocation patterns and interactions with the abiotic and biotic environment.
In this study, we quantified mean, variance, skewness and kurtosis of 495 individual flowering schedules (5287 flowers) over three years, and assessed phenotypic selection on these aspects of the within-individual distribution of opening dates in the perennial herb Lathyrus vernus. We also explored how selection on within-individual variation in flowering schedules was related to effects on two fitness components: fruit set and the proportion of seeds escaping pre-dispersal predation.
Within-individual variation in phenology was larger than, or at least similar to, among-individual variation in all years. We found phenotypic selection on several aspects of individual flowering schedules. In one year, selection favoured plants with higher variance in opening dates, and this coincided with a higher fruit set in plants with an increased spread of the flowering schedule. In two of the study years, selection favoured a higher asymmetry of the flowering schedule, and plants with more right-skewed distributions had higher fruit set and higher proportions of seeds escaping predation. Both fruit set and seed predation increased with an earlier mean flowering, resulting in no net selection on mean flowering date.
Synthesis. Our results suggest that phenotypic selection on the spread and shape of flower opening date distributions might be at least as important as selection on the mean flowering date. In a broad sense, this implies that we should consider the entire trait distribution if we aim to understand the evolution of traits that are expressed multiple times within individuals.
README: Selection favors high spread and asymmetry of flower opening dates within plant individuals
https://doi.org/10.5061/dryad.2jm63xsz1
This data includes data on individuals (data_ids_clean.csv) and on individual flowers (data_id_flowers_clean.csv) coming from recordings of 5287 individual flowers of Lathyrus vernus belonging to 495 flowering events (i.e. one individual flowering in one year) over three years. It also includes weather data from a nearby meteorological station (weather_clean.csv). The code used in the manuscript is on the file 5_code_analyses_dryad.Rmd.
Description of the data and file structure
The file data_ids_clean.csv contains the following columns:
- id: identifier of the plant individual
- fr_set: fruit set (proportion of flowers that developed to mature fruits)
- n_seed: total number of seeds
- fitness: total number of intact seeds
- prop_seed_preyed: proportion of preyed seeds
- year: the year of the flowering event
- var: variance of opening dates
- skew: skewness of opening dates
- kurt: kurtosis of opening dates
- avFD_v: mean opening date (expressed as the number of days after the vernal equinox in each year)
- n_fl_std: number of flowers (standardized)
- avFD_std: mean opening date (standardized)
- var_std: variance of opening dates (standardized)
- skew_std: skewness of opening dates (standardized)
- kurt_std: kurtosis of opening dates (standardized)
- fitness_rel: relativized fitness
- n_fl: number of flowers
- n_mat_intact_fr: number of mature intact fruits
- prop_seeds_escpred: proportion of seeds escaping predation
- n_fl_log: number of flowers (log)
- n_fl_log_std: number of flowers (log), standardized
- npr_seeds: number of non-predated seeds
- pr_seeds: number of predated seeds
The file data_id_flowers_clean.csv contains the following columns:
- id: identifier of the plant individual
- year: the year of the flowering event
- opening_date_c: opening date of each individual flower (expressed as a calendar date)
- opening_date_v: opening date of each individual flower (expressed as the number of days after the vernal equinox in each year)
The file weather_clean.csv contains the following columns:
- date: the date of the recording
- year: the year of the recording
- month: the month of the recording
- day: the day of the recording
- mean: the daily mean temperature recorded (ºC)
- min: the daily minimum temperature recorded (ºC)
- max: the daily maximum temperature recorded (ºC)
The file 5_code_analyses_dryad.Rmd is an R notebook all the code needed to run the analyses on the manuscript. This code is uploaded as software to Zenodo linked in this publication.