DOI: 10.5061/dryad.jwstqjqk5
title: Data from: A leaf-surface fungus mediates interactions between leafcutter bees and the plants they cut to line their nests

description: Many arthropods damage leaves, a phenomenon that is foundational to their
 impacts on terrestrial ecosystems. Leaf traits, including chemistry, shape
 these interactions. In turn, leaf-surface (phylloplane) microbes can act
 directly or in concert with chemistry to influence leaf choice, especially
 by insects whose reproductive success is tied to prolonged contact with
 leaf surfaces. Leafcutter bees (Megachile spp.) cut discs from leaves to
 line their nests, with leaves and their associated microbes forming the
 environment in which bees’ offspring develop. We predicted that
 phylloplane microbial communities act in concert with leaf chemistry to
 mediate interactions between the leafcutter bee M. lippiae and the plants
 they cut. We surveyed phylloplane communities on rose (Rosa × hybrida,
 Rosaceae) leaflets that were cut vs. not cut by wild M. lippiae. Then, we
 inoculated rose leaves in the field to test the effect of abundant
 microbes on cutting. Microbial communities differed between cut and
 non-cut leaflets. In particular, Aspergillus spp. were over-represented on
 cut leaflets, and Alternaria sp. and Bacillus sp. were over-represented on
 non-cut leaflets. When inoculated onto rose leaves, Alternaria and
 Bacillus did not affect cutting, but Aspergillus resulted in twice as many
 cuts as sham-inoculated leaves. To test whether Aspergillus could protect
 bee nests against pathogens, we grew Aspergillus with two pathogenic
 fungi: the generalist insect pathogen Beauveria bassiania, and three
 strains of Ascosphaera that cause chalkbrood disease in bee larvae.
 Aspergillus did not inhibit the growth of Beauveria, but it markedly
 slowed the growth of Ascophera. To clarify whether these phylloplane
 microbes reflect differences in leaf chemistry or are instead independent
 cues that influence leaf cutting, we used liquid chromatography-mass
 spectroscopy to characterize the metabolome of cut and non-cut leaflets.
 Chemistry did not differ between cut and non-cut leaflets, nor was it
 related to microbial community composition. Our results suggest that
 Aspergillus, a common member of rose phylloplane communities, mediates
 interactions between leafcutter bees and roses, potentially affecting the
 fitness of both partners. This study reveals a previously unexplored
 microbial dimension to plant-insect associations.
description: # A leaf-surface fungus mediates interactions between leafcutter bees and
 the plants they cut to line their nests
 [https://doi.org/10.5061/dryad.jwstqjqk5](https://doi.org/10.5061/dryad.jwstqjqk5) ## Description of the data and file structure These files contain data on the phylloplane microbial communities and metabolomes of rose leaflets. We collected these data to understand how the leaf microbiome and chemistry affect cutting by leafcutter bees. ### Files and variables #### File: rp_compounds_table.xlsx **Description:** Contains a list of compounds identified in metabolomics analyses along with chromatographic and spectral data. Intended as a supplementary table, not a raw data file. #### File: full_microbial_communities_hilic.csv **Description:** Contains metabolomic data collected through hydrophobic interaction liquid chromatography, plus morphotype-based phylloplane microbial community data, for 20 rose leaflets. ##### Variables * ind: identifier for the rose individual. Letter(s) indicate cultivar: I="Impatient", RG="Red Gold", SF="Sun Flare", SS="Summer Snow", UB/UT=unlabeled * cutstatus: whether a leaf was cut by a leafcutter bee or not * leaftreat: W=washed with sterile water, NW=not washed. * prop.asp.Nigri: proportion of CFU from the leaf that were fungi belonging to the *Aspergillus* sect. Nigri * asp.nigri: presence/absence of *Aspergillus* sect. Nigri * delta.Gluconic acid.delta.lactone.x and similar: these and the following columns are normalized area under curve values for a given feature. Features that could not be confidently identified have been given alphanumeric names (e.g., us100) * M_200 and similar: unique microbial morphotype identifiers * M_200.rel and similar: relative abundance of morphotypes #### File: full_microbial_communities_rp.csv **Description:**  Contains metabolomic data collected through reversed-phase liquid chromatography, plus morphotype-based phylloplane microbial community data, for 20 rose leaflets. ##### Variables * ind: identifier for the rose individual. Letter(s) indicate cultivar: I="Impatient", RG="Red Gold", SF="Sun Flare", SS="Summer Snow", UB/UT=unlabeled * cutstatus: whether a leaf was cut by a leafcutter bee or not * leaftreat: W=washed with sterile water, NW=not washed. * prop.asp.Nigri: proportion of CFU from the leaf that were fungi belonging to the *Aspergillus* sect. Nigri * asp.nigri: number of CFU from the leaf that were fungi belonging to the *Aspergillus* sect. Nigri * delta.Gluconic acid.delta.lactone.x and similar: these and the following columns are normalized area under curve values for a given compound. Compounds that could not be confidently identified have been given alphanumeric names (e.g., us100) * M_200 and similar: unique microbial morphotype identifiers * M_200.rel and similar: relative abundance of morphotypes #### File: inoculation_experiment.csv **Description:** Results of the rose leaf inoculation experiment ##### Variables * plot: identifier for a section of the rose garden * variety: rose cultivar identifier. GB="Gene Boerner", I="Impatient", IF="Ivory Fashion", MK="Margo Koster", RG="Red Gold", SF="Sun Flare", SS="Summer Snow", U=unlabeled * individual: rose individual * branch: branch identifier * Leaf: leaf identifier * treatment: C=unmanipulated control, IC=inoculation control, M2=Aspergillus, M9=Bacillus, M122=Alternaria * leaflets.x: number of leaflets on the leaf * total: number of cuts that accumulated during the experiment * baseline_cuts: number of cuts existing on the leaf before treatment application #### File: hilic_all_leaflets_aspergillus.csv **Description:** Contains metabolomic data collected through reversed-phase liquid chromatography, plus data on whether a leaf hosted Aspergillus ##### Variables * ind: rose individual. Letter(s) indicate cultivar: I="Impatient", RG="Red Gold", SF="Sun Flare", SS="Summer Snow", UB/UT=unlabeled * cutstatus: whether a leaf was cut by leafcutter bees, cut-C or not cut-NC * leaftreat: W=washed with sterile water, NW=not washed, SS=surface sterilized * delta-Gluconic acid delta-lactone and similar: normalized area under the curve values for a given compound. Compounds that could not be confidently identified have been given alphanumeric names (e.g., us100). ".rel" after a compound name means that a column has relative abundance data. * Prop.asp.Nigri: relative abundance of fungi belonging to *Aspergillus* sect Nigri * prop.asp.all: relative abundance of all *Aspergillus* * asp.nigri: presence/absence of fungi belonging to *Aspergillus* sect Nigri * asp.all: presence/absence of all *Aspergillus* #### File: pathogen_inhibition.csv Description: Results of dual-culture experiments  ##### Variables * phylloplaneID: isolate code for phylloplane fungus * pathogenID: genus and/or species name for pathogen * pathogen toward: growth of pathogen toward phylloplane fungus * pathogen. away: growth of the pathogen away from the phylloplane fungus * phylloplane. genus: genus of phylloplane fungus * Percent inhibition: calculated percent inhibition of radial growth #### File: rose_phylloplane_communities.csv **Description:** Data on rose phylloplane microbial communities from an observational survey ##### Variables * plot: sub-area of the rose garden * class: HTR=Hybrid Tea Rose, FR=Floribunda Rose, GR=Grandiflora Rose * cultivar: AZ="Arizona", CI="Chrysler Imperial", FC="Fragrant Cloud", FP="First Prize", GB="Gene Boerner", I="Impatient", IF="Ivory Fashion", M="Medallion", MK="Margo Koster", O="Oregold", P="Peace", RG="Red Gold", SF="Sun Flare", SS="Summer Snow", T="Tropicana", UB=unlabeled, V="Valentine" * Individual: individual identifier * Replicate: replicate identifier * cut_notcut: whether the leaflet was cut by a leafcutter bee or not * area: sampled leaflet area * M_1 and similar: abundance (in CFU) of a given morphotype on a leaflet. M_2=*Aspergillus* sect. Nigri, M_9=*Bacillus*, M_122=*Alternaria*. ".pres" after a morphotype indicates that the column instead has presence/absence data for that morphotype. * unknown: abundance (in CFU) of microbes that could not be assigned a morphotype, usually due to contamination * total_abundance: total CFU for a leaflet * abund*_*per_area: CFU/leaflet area #### File: rp_all_leaflets_aspergillus.csv **Description:** Contains metabolomic data collected through hydrophilic interaction liquid chromatography, plus data on whether a leaf hosted Aspergillus ##### Variables * ind: rose individual. Letter(s) indicate cultivar: I="Impatient", RG="Red Gold", SF="Sun Flare", SS="Summer Snow", UB/UT=unlabeled * cutstatus: whether a leaf was cut by leafcutter bees * leaftreat: W=washed with sterile water, NW=not washed, SS=surface sterilized * beta-Alanine and similar: normalized area under the curve values for a given compound. Compounds that could not be confidently identified have been given alphanumeric names (e.g., us100). ".rel" after a compound name means that a column has relative abundance data. * Prop.asp.Nigri: relative abundance of fungi belonging to *Aspergillus* sect Nigri * prop.asp.all: relative abundance of all *Aspergillus* * asp.nigri: presence/absence of fungi belonging to *Aspergillus* sect Nigri * asp.all: presence/absence of all *Aspergillus*