README
======

Dataset title:
Data for: Abundance of short- and long-tongued bees, and their impact on red clover seed production in four cultivars grown across a large latitude range

Dataset identifier:
https://doi.org/10.5878/5v4x-rd92

Creators:
Kajsa Svensson, Veronika Hederström, Ida Valentin, Sara Lindholm, Linda Öhlund, Mattias C. Larsson, Åsa Lankinen

Responsible organization:
Swedish University of Agricultural Sciences

Recommended Citation:
Svensson, K. (2026). Data för: Abundance of short- and long-tongued bees, and their impact on red clover seed production in four cultivars grown across a large latitude range (Version 1) [Data set]. Sveriges lantbruksuniversitet. https://doi.org/10.5878/5v4x-rd92
See the Researchdata.se catalogue entry for this dataset - accessible via the DOI link above - for complete metadata, including the dataset description, contact information and information about how to obtain the dataset. 

Description: 
Data on seed yield, seed set, pollinating bee and weevil abundances, and plant traits collected from four red clover cultivars in field trials at six sites in Sweden over two years. 
Data from cage studies on seed yield, density of Bombus terrestris, flower head density, and pollinator surveys in open plots in tetraploid red clover over two years.

License: 
CC0


Dataset organization
--------------------

The data set contains eight data files.

Two files contains data from a cage study where seed yield from tetraploid red clover was compared from cages with different densities of Bombus terrestris in two years. These file are:
- Cage_study_seed_yield
- Cage_study_pollinators

Six files are from the field trials including four red clover cultivars grown at six sites in Sweden over two years. 
Five of these files are separated based on how data was aggregated for the different analyses, and are named according to which analyses they were used for.
These file are:
- Correlation_analyses_seed_yield_and_total_and_flowering_flower_head_densities
- Pollinator_abundance_models
- Seed_set_and_florets_per_flower_head_models
- Seed_yield_and_weevil_models_and_correlation_analyses_seed_set_and_florets_per_flower_head
- Total_flower_head_density_model

One file contains extra information from three (Kölbäck, Lännäs and Svalöv) of the six study sites. This information includes seed weight from whole plots, thousand seed weight and germination percentage of seeds. This information was used to analyse how well seed weight from whole plots were correlated with seed weight from small squares used in the study, and quality of seeds.
The file is:
- Seed_yield_whole_plots_thousand_seed_weight_and_germination


Datafile descriptions
----------------------

Columns included in all files:
Year - (YYYY)
Site - For the field trials, the sites are Bjertorp, Kölbäck, Lännäs, Röbäcksdalen, Svalöv, Ås (see Spatial_information_study_sites for coordinates and other information). For the cage study, the sites are South 1, South 2, North 1, North 2, North 3 (see Spatial_information_study_sites for information).
Cultivar - Name of red clover cultivar. Yngve = diploid cultivar. Betty, Kelly, Peggy, Vicky = tetraploid cultivars.

Cage_study_pollinators (number of rows=6, number of columns=4)
This data was used to compare the pollinators in the open plots among sites used for the cage study.
N_short - Number of short-tongued bees (sum of lap, pra, a_mellifera, sor, ter_incl_robbers)
N_long - Number of long-tongued bees (sum of dis, hor, hum, mus, sub, pas, rud, syl)

Cage_study_seed_yield (number of rows=21, number of columns=9)
This data was used for the cage study seed yield and total and flowering flower head densities analyses.
Columns:
Treatment - Empty = empty cage, Low-density = ~ 5 individuals of B. terrestris, High-density = ~ 50 individuals of B. terrestris, Open plot = no cage, access to wild pollinators.
Seed_yield_standardized - (g) Seed yield. Standardized to g per m1 due to different sizes of the cages and open plots at the different sites.
Buds - Number of buds (flower heads with < 5 open florets and the rest immature)
Flowering_flower_heads - Number of flowering flower heads (flower heads with > 5 open florets)
Wilted_flower_heads - Number of wilted flower heads (flower heads with < 5 open florets and the rest wilted)
Total_flower_heads - Total number of buds, flowering and wilted flower heads

Correlation_analyses_seed_yield_and_total_and_flowering_flower_head_densities (number of rows=86, number of columns=9)
This data was used for correlation analyses including seed yield and total and flowering flower head densities. 
Columns:
Plot - One out of two plots that were used as replicates for each cultivar, site and year.
Seed_weight_g - (g) Seed weight as average value from three 0.25 m2 quadrats per plot, averaged per year/site/cultivar/plot
Buds - Number of buds (flower heads with < 5 open florets and the rest immature) as average value from three 0.25 m2 quadrats per plot, averaged per year/site/cultivar/plot
Flowering_flower_heads - Number of flowering flower heads (flower heads with > 5 open florets) as average value from three 0.25 m2 quadrats per plot, averaged per year/site/cultivar/plot
Wilted_flower_heads - Number of wilted flower heads (flower heads with < 5 open florets and the rest wilted) as average value from three 0.25 m2 quadrats per plot, averaged per year/site/cultivar/plot
Total_flower_heads - Total number of buds, flowering and wilted flower heads as average value from three 0.25 m2 quadrats per plot, averaged per year/site/cultivar/plot

Pollinator_abundance_models (number of rows=258, number of columns=21)
This data was used for pollinator abundance models.
Columns:
Survey round - A number between 1-3. Each plot was surveyed three times over the season, with approximately one week in between.
dis - Number of Bombus distinguendus
hor - Number of Bombus hortorum
lap - Number of Bombus lapidarius
pas - Number of Bombus pascuorum
ter_incl_robbers - Number of Bombus terrestris agg. inclusive nectar robbers (this was the variable used in final results)
ter_excl_robbers - Number of Bombus terrestris agg. exclusive nectar robbers
syl - Number of Bombus sylvarum
sub - Number of Bombus subterraneus
rud - Number of Bombus ruderarius
sor - Number of Bombus soroëensis
a_mellifera - Number of Apis mellifera
hum - Number of Bombus humilis
pra - Number of Bombus pratorum
mus - Number of Bombus muscorum
N_short - Number of short-tongued bees (sum of lap, pra, a_mellifera, sor, ter_incl_robbers)
N_long - Number of long-tongued bees (sum of dis, hor, hum, mus, sub, pas, rud, syl)
Flowering_flower_heads - Number of flowering flower heads (flower heads with > 5 open florets) as average value from three 0.25 m2 quadrats per year/site/cultivar/plot/survey round

Seed_set_and_florets_per_flower_head_models (number of rows=126, number of columns=22)
This data was used for seed set and florets per flower head models.
Survey_round - A number between 1-3. Each plot was surveyed three times over the season, with approximately one week in between.
dis - Number of Bombus distinguendus
hor - Number of Bombus hortorum
lap - Number of Bombus lapidarius
pas - Number of Bombus pascuorum
ter_incl_robbers - Number of Bombus terrestris agg. inclusive nectar robbers (this was the variable used in final results)
ter_excl_robbers - Number of Bombus terrestris agg. exclusive nectar robbers
syl - Number of Bombus sylvarum
sub - Number of Bombus subterraneus
rud - Number of Bombus ruderarius
sor - Number of Bombus soroëensis
a_mellifera - Number of Apis mellifera
hum - Number of Bombus humilis
pra - Number of Bombus pratorum
mus - Number of Bombus muscorum
N_short - Number of short-tongued bees (sum of lap, pra, a_mellifera, sor, ter_incl_robbers)
N_long - Number of long-tongued bees (sum of dis, hor, hum, mus, sub, pas, rud, syl)
Florets_per_flower_head - Number of florets per flower head as average value per year/site/cultivar/survey round
Seed_set - Number of seeds (including developed seeds with weevil damage) per number of florets per flower head, as average value per year/site/cultivar/survey round

Seed_yield_and_weevil_models_and_correlation_analyses_seed_set_and_florets_per_flower_head (number of rows=43, number of columns=23)
This data was used for seed yield and weevil abundance models, and correlation analyses including seed set and number of florets per flower head.
Columns:
dis - Number of Bombus distinguendus
hor - Number of Bombus hortorum
lap - Number of Bombus lapidarius
pas - Number of Bombus pascuorum
ter_incl_robbers - Number of Bombus terrestris agg. inclusive nectar robbers (this was the variable used in final results)
ter_excl_robbers - Number of Bombus terrestris agg. exclusive nectar robbers
syl - Number of Bombus sylvarum
sub - Number of Bombus subterraneus
rud - Number of Bombus ruderarius
sor - Number of Bombus soroëensis
a_mellifera - Number of Apis mellifera
hum - Number of Bombus humilis
pra - Number of Bombus pratorum
mus - Number of Bombus muscorum
N_short - Number of short-tongued bees (sum of lap, pra, a_mellifera, sor, ter_incl_robbers)
N_long - Number of long-tongued bees (sum of dis, hor, hum, mus, sub, pas, rud, syl)
Seed_weight_g - (g) Seed weight as average value from three 0.25 m2 quadrats per plot, averaged per year/site/cultivar
Protapion_per_head - Number of seed eating Protapion weevils (P. apricans, P. assimile and P. trifolii) per flower head from hatching tubes, averaged per year/site/cultivar
Seed_set - Number of seeds (including developed seeds with weevil damage) per number of florets per flower head, averaged by year/site/cultivar
Florets_per_flower_head - Number of florets per flower head as average value per year/site/cultivar

Seed_yield_whole_plots_thousand_seed_weight_and_germination (number of rows=48, number of columns=7)
This data was used to do correlation analyses between seed weight for the whole plot and seed weight from small squares used in the study. It was also used for analysing seed quality (thousand seed weight and germination percentage).
Data is missing for the cultivar Vicky in Lännäs 2020 due to damaged plants. In Svalöv 2021, the two plots for each respective cultivar were harvested together.
Columns:
Seed_weight_plot_g - (g) Seed weight harvested from the whole plot
Thousand_seed_weight_g - (g) The weight of thousand seeds
Germination_percentage - (%) Percentage of germinated seeds, a measure of seed quality. This was only measured in 2020.

Total_flower_head_density_model (number of rows=129, number of columns=8)
This data was used for the total flower head density model.
Columns:
Survey_round - A number between 1-3. Each plot was surveyed three times over the season, with approximately one week in between.
Buds - Number of buds (flower heads with < 5 open florets and the rest immature) as average value from three 0.25 m2 quadrats per plot, averaged per year/site/cultivar/survey round
Flowering_flower_heads - Number of flowering flower heads (flower heads with > 5 open florets) as average value from three 0.25 m2 quadrats per plot, averaged per year/site/cultivar/survey round
Wilted_flower_heads - Number of wilted flower heads (flower heads with < 5 open florets and the rest wilted) as average value from three 0.25 m2 quadrats per plot, averaged per year/site/cultivar/survey round
Total_flower_heads - Total number of buds, flowering and wilted flower heads as average value from three 0.25 m2 quadrats per plot, averaged per year/site/cultivar/survey round