Internet images reveal bumblebee-mimicking hoverflies follow models in preferring blue flowers, but retain the typical hoverfly attraction to yellow
Data files
Oct 09, 2025 version files 296.44 KB
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README.md
3.44 KB
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Supplementary_file_S4_-_phylogeny.nex
9.70 KB
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Syrphid_behavioural_mimicry_-_results_and_code.Rmd
34.91 KB
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Table_S1_model-mimic_ids.xls
43.52 KB
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Table_S2_head_width.csv
1.84 KB
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Table_S2_head_width.xlsx
11.74 KB
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Table_S3_main_data.csv
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Table_S3_main_data.xlsx
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Table_S4_species_pairs.csv
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Table_S4_species_pairs.xlsx
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Abstract
Batesian mimics, such as hoverflies, resemble noxious species that predators avoid, such as bees. Such resemblance can be behavioural as well as morphological. Unlike other Hymenopterans, eusocial bees commonly prefer blue flowers. In contrast, flies generally prefer yellow and white. We predicted that hoverflies mimicking eusocial bees would prefer blue rather than yellow flowers, following their models. We gathered internet photographs of flower-visiting bees and wasps, their hoverfly mimics, and non-mimetic hoverflies, and compared the colours of the visited flowers. Flowers visited by bumblebees were "bluer" than those visited by other hymenopterans (honeybees, social wasps, and solitary bees). Correspondingly, flowers visited by bumblebee-mimicking hoverflies were bluer than those visited by non-mimics, and as blue as those visited by bumblebees. There was no such pattern in flower "yellowness", where all flies and most hymenopterans preferred similar yellowness, and only bumblebees chose less-yellow flowers than others. Our study demonstrates changes in microhabitat choice associated with Batesian mimicry across a diverse clade of flies. Our findings suggest selection for behavioural mimicry, or that common microhabitats select for morphological mimicry. Mildly noxious models such as bumblebees exert particularly strong selection for mimetic accuracy, suggesting that habitat-choice mimicry may be selected to enhance morphological mimicry.
Short summary of the study
We gathered internet photographs of flower-visiting bees and wasps, their hoverfly mimics, and non-mimicking hoverflies, and compared the colours of the visited flowers. We predicted that, driven by selection for enhanced mimicry, bee-mimicking hoverflies would have switched flower preference from yellow to blue, to follow the flower choices of their models.
Files included
Syrphid_behavioural_mimicry_-_results_and_code.Rmd
R Markdown file that reproduces the results section of the paper from the files enclosed here.
Some figures are produced in R but compiled manually - this is indicated in the code comments.
Table_S1_model-mimic_ids.xls
Table of mimics and corresponding models compiled from literature (modified from Gilbert, F. 2025 (in press). The Biology of the Hoverflies (Diptera, Syrphidae). London, England: CABI and Royal Entomological Society).
NB. References are given in the separate worksheet.
This file is not used in the code, so there is no corresponding .csv file (see Table S4 species pairs.csv)
Hoverfly species: The species in question (divided into bumblebee mimics, honeybee mimics, solitary bee mimics, social wasp mimics and non-mimics)
Model genera: Genera of models identified in the literature (see references).
Species identified: species of models identified in the literature (see references).
Table_S2_head_width.xlsx
Table_S2_head_width.csv
Table of head widths for syrphids in dataset. These data are a combination of direct measurement and interpolation based on other traits (see text for details).
species: Species of Syrphid
head width (mm): Head width in mm
Interpolated or measured: Whether interpolated or measured (see text for details)
Table_S3_main_data.xlsx
Table_S3_main_data.csv
Main data table - data on morphotype group (see text for details), model species (for mimics), and median RGB flower colour for each photograph.
Metadata are contained in a separate worksheet in the .xlsx file and are replicated here:
species: Species name of mimic or model
group: morphotype group (see text for details): bbee = bumblebee; hbee = honeybee; sbee = solitary bee; swasp = social wasp; mim = mimic; non = non-mimic; mod = model
pair_species Model species (see text and Table S1 for details). Note that non-mimics are coded NA here because they are not mimics and do not have a model.
pair2: Model search string; for use in grouping model-mimic pairs (see code for details)
r: Median red content of flower cutout (0-255)
g: Median green content of flower cutout (0-255)
b: Median blue content of flower cutout (0-255)
Table_S4_species_pairs.xlsx
Table_S4_species_pairs.csv
Table of species pairs connecting models to mimics and vice versa.
group: morphotype group (see text for details): bbee = bumblebee; hbee = honeybee; sbee = solitary bee; swasp = social wasp; mim = mimic; non = non-mimic; mod = model
pair2: Model search string; for use in grouping model-mimic pairs (see code for details)
pair_id: Model-mimic pair ID
Supplementary_file_S4_-_phylogeny.nex
Syrphid phylogeny at the genus level in NEXUS format.
For analysis, species in the dataset are added in to this at the coding stage (see code for details).
