In flowering plants, the evolution of females is widely hypothesized to be the first step in the evolutionary pathway to separate male and female sexes, or dioecy. Natural enemies have the potential to drive this evolution if they preferentially attack hermaphrodites over females. We studied sex-based differences in exposure to anther-smut (Microbotryum), a sterilizing pollinator-transmitted disease, in Dianthus pavonius, a gynodioecious perennial herb. We found that within a heavily diseased population, females consistently had lower levels of Microbotryum spore deposition relative to hermaphrodites and that this is difference was driven by rapid floral closing in females following successful pollination. We further show that this protective closing behavior is frequency-dependent; females close faster when they are rare. These results indicate that anther-smut disease is an important source of selection for females, especially since we found in a common garden experiment no evidence that females have any inherent fecundity advantages over hermaphrodites. Finally, we show that among populations, those where anther-smut is present have a significantly higher frequency of females than those where the disease is absent. Taken together our results indicate that anther-smut disease is likely an important biotic factor driving the evolution and maintenance of females in this gynodioecious species.
bag-experiment
Longevity data for flowers in the bagged -plant experiment (Fig 3b)
tagged-plants longevity
Longevity data for marked plants in the four plots. Data also shows the number of inflorescences on each marked plant. Spatial data included: x, y coordinates, and the total number of plants and number of diseased plants in that coordinate at the mid-point census.
spore-data on tagged flowers
Data file containing all flowers from tagged plants in the four local garelli plots where we were able to count the spores. Note that there are some plants where the longevity is NA (becuase the flower was missed during one or more of the open/closed surveys). We did the overall ANOVA analysis of spore deposition on the full data set (eg. Fig 3c) but restricted the ANCOVA analysis to just those samples where we had both longevity and spore data. Other columns as in the longevity data set.
Phenology plot data
Phenology plot data (Figure 2). Data file contains the total number of healthy hermaphrodites (HH), healthy female (MS), and diseased (D) plants and the total number of flowers of each type per 1m quad within four different local sites at four times (early, mid, and late).
ovule.data.dryad
Data on the number of ovules from field-collected hermaphrodite (HH) and female (MS) plants.
sex ratio across valley transects
Data file giving the elevation, population size, disease prevalence, and frequency of females for sampled populations across the broader maritime alps (Figure 5)
Flower size and number in greenhouse
Data file gives the number of inflorescences (inflos) and size in mm of the first flower (flower1) for plants from maternal half-sib families (fam) collected from either the upper or lower portion of our long-term transect one. The column 'Female' indicates sex: 1=female, 0=herm.
Flower size.xlsx
Flower size -field
R file with flower sizes in mm of samples hermaphrodite (hh) and female (ms) flowers near Rifugio Garelli
seed set greenhouse
File showing the number of capsules and total seeds produced from sympatric and allopatric crosses of Dianthus pavonius flowers from three populations grown in the greenhouse.
inbreeding depression data for aster
Data file showing fitness data for selfed and outcrossed progeny of plants from three different valleys (s=selfed, w=within pop cross, o=outcross to a different valley). Fitness variables are: survival to early juvenile stage (surv.16), survival to 1 year (surv.17), whether of not plants flowered (flwr.17) and the total number of inflorescences produced (infls.17).
infloresence numbers in the field
Number of infloresences for each hermaphrodite (HH) and female (MS) plant within transect 1. (Data shown in fig 6b)
Closing data from floral array experiment
Data file with the closing time information on each hermaphrodite (hh) and female (MS) plant in sex-ratio floral array experiment (Fig 4). For the column 'missing' a 1 indicates the flower went missing during the experiment (likely blew away) and 0 indicates present and data available. The close.yes.no column indicates wether the flower was still open by the end of the experiment (1=closed, 0=still opened). Flowers with a '1' in this column also have a data of closure recorded.