DOI: 10.5061/dryad.cjsxksnf9
title: Do flower-colonizing microbes influence floral evolution? A test with fast-cycling Brassica

description: Pollinators are thought to be the main drivers of floral evolution.
 Flowers are also colonized by abundant communities of microbes that can
 affect the interaction between plants and their pollinators. Very little
 is known, however, about how flower-colonizing microbes influence floral
 evolution. Here we performed a six-generation experimental evolution study
 using fast-cycling Brassica rapa, in which we factorially manipulated the
 presence of pollinators and flower microbes to determine how pollinators
 and microbes interact in driving floral evolution. We measured the
 evolution of six morphological traits, as well as plant mating system and
 flower attractiveness. Only one of the six traits (flower number) evolved
 in response to pollinators, while microbes did not drive the evolution of
 any trait, nor did they interact with pollinators in driving evolution of
 morphological traits. Moreover, we did not find evidence that pollinators
 or microbes affected the evolution of flower attractiveness to
 pollinators. However, we found an interactive effect of pollinators and
 microbes on the evolution of autonomous selfing, a trait that is expected
 to evolve in response to pollinator limitation. Overall, we found only
 weak evidence that microbes mediate floral evolution. However, our ability
 to detect an interactive effect of pollinators and microbes might have
 been limited by weak pollinator-mediated selection in our experimental
 setting. Our results contrast with previous (similar) experimental
 evolution studies, highlighting the susceptibility of such experiments to
 drift and to experimental artefacts.
description: # Do flower-colonizing microbes influence floral evolution? A test with
 fast-cycling Brassica
 [https://doi.org/10.5061/dryad.cjsxksnf9](https://doi.org/10.5061/dryad.cjsxksnf9) Data and code to analyse the effect of pollinators and microbes on the evolution of fast-cycling *Brassica rapa* in an experimental evolution study. ## Description of the data and file structure There are four datasets: \- "Floral_traits" \- "Autonomous-selfing" \- "Choice_assays_brassica" \- "UV_photos" **Floral_traits** This dataset provides information on six plant traits measured on individuals of *Brassica rapa* from three different generations of experimental evolution (1, 7, and 8) and four treatments (presence or absence of pollination by bumblebees and inoculation by microbes, in a factorial design). This dataset was used with the code "Floral_traits_analysis_SR". Missing values in the dataset are identified as "NA". Generation: Generation of experimental evolution for which the traits were measured. Replicate: Name of the replicate. Each treatment was divided in three replicates (A, B, and C). Family: Individual ID for the plants within a treatment and replicate. ID: Individual ID for the plants within a generation. Treatment: One of the four treatments used during the experiment. PC = Pollination by bumblebees without microbe inoculation, HC = hand-pollination without microbe inoculation, PB = Pollination by bumblebees with microbe inoculation, and HB = hand-pollination with microbe inoculation. Height: Height of the plant in centimeters from the base of the stem to the top of the highest flower. N_flowers: Number of open flowers at the time the measurements were taken. N_tot: Number of flowers including open flowers, buds, and wilted flowers. Pistil_length: Average length in millimeters of the pistils of three flowers from a given individual. Stamen_length: Average length in millimeters of the long stamens of three flowers from a given individual. Petal_length: Average length in millimeters of the petals of three flowers from a given individual. Proportion_UV_absorbing: Proportion of the petal area that is UV absorbing, measured for a single flower per individual. **Autonomous-selfing** This dataset provides information on the ability of *Brassica rapa* individuals from generation 8 to produce seeds without pollinators. This dataset was used with the code "Autonomous_selfing_SR". Family: Individual ID for the plants within a treatment and replicate. Treatment: One of the four treatments used during the experiment. PC = Pollination by bumblebees without microbe inoculation, HC = hand-pollination without microbe inoculation, PB = Pollination by bumblebees with microbe inoculation, and HB = hand-pollination with microbe inoculation. Replicate: Name of the replicate. Each treatment was divided in three replicates (A, B, and C). Number of flowers: Total number of flowers including open flowers, buds, and wilted flowers. Number of seeds: Number of seeds produced from autonomous selfing for a given individual. Number of fruits: Number of fruits produced from autonomous selfing for a given individual. Selfing: Whether the individual produced seeds from autonomous selfing. This variable was coded as 0 for absence of autonomous selfing and 1 for presence of autonomous selfing. An individual was considered as autonomous selfing if at least one seed was produced. **Choice_assays_brassica** This dataset provides information on the first choice of bumblebees (first plant visited) to plants of Brassica rapa from the four treatments at generation 8 in choice assays performed in flight cages. Each assay included a single bumblebee and four plants, one of each treatment, placed in a square configuration (one plant in each corner). This dataset was used with the code "Bee_choice_assays_SR". Round: Unique ID for the assays performed with a given bumblebee colony. Colony: Unique ID for the bumblebee colonies used during the experiment. Treatment: Treatment to which the plant was exposed during experimental evolution. PC = Pollination by bumblebees without microbe inoculation, HC = hand-pollination without microbe inoculation, PB = Pollination by bumblebees with microbe inoculation, and HB = hand-pollination with microbe inoculation. Replicate: Name of the replicate. Each treatment was divided in three replicates (A, B, and C). Position: Position of the plant in the square configuration. Each corner of the square was given a number from 1 to 4. N_flowers: Number of open flowers during the choice assay. Choice: Whether the plant was the first choice of the bumblebee during the assay. This variable was coded as 0 when the plant was not the first choice and 1 when the plant was the first choice. **UV_photos** Raw digital pictures of Brassica rapa petals taken under ultraviolet light using an ultraviolet filter. A 1 centimeter line is used as scale on every picture. The file names are composed of the generation of experimental evolution (e.g., "G1"), the treatment (e.g., "PC"), the family, and a unique ID for every plant of a generation (as in the "Floral_traits" data file).