DOI: 10.5061/dryad.fttdz093r
title: Data from: Off-target drift of the herbicide dicamba disrupts plant-pollinator interactions via novel pathways

description: While herbicide use in agriculture is expected to have many effects on
 surrounding weed communities, it is largely unknown how plant exposure to
 sublethal doses of herbicide may subsequently impact plant-pollinator
 interactions. We tested the hypothesis that sublethal herbicide exposure
 indirectly alters plant-pollinator interactions through changes in plant
 traits, and specifically through alterations in floral display. Using a
 common garden experiment, we exposed 11 weed species to the herbicide
 dicamba and examined the potential for changes in pollinator abundance and
 patterns of pollinator visitation as well as alterations to plant traits.
 We found variation among plant species in the extent of damage from
 dicamba drift, and variation in size, flowering time, and flower displays,
 with some plant species showing negative impacts and others showing little
 effect. Pollinator frequencies were reduced in dicamba-exposed plots, and
 pollinator visits were reduced for some weed species yet not others.
 Structural equation modeling revealed that the relationship between flower
 display and pollinator visits was disrupted in the presence of dicamba.
 Our study provides the most comprehensive picture to date of the impacts
 of herbicide drift on plant-pollinator interactions, with findings that
 highlight an underappreciated role of services supplied by weedy
 communities.
description: Plant growth, damage, day of flowering and number of flowers
 following dicamba drift exposure were measured on eleven commen weed
 species during a replicated common garden field experiment. Data has been
 processed and cleaned to reflect the contents of this study. Scripts for
 the analyses in this study are also included.
description: # Off-target drift of the herbicide dicamba disrupts plant-pollinator
 interactions via novel pathways Regina S Baucom1, Veronica Iriart, Anah
 Soble, Matthew R. Armstrong, and Tia-Lynn Ashman
 [https://doi.org/10.5061/dryad.5x69p8ddt](https://doi.org/10.5061/dryad.5x69p8ddt) ## Description of the data and file structure ### Key for headers in "DicambaMasterDatasheet2021.csv" and "Pollinator\_2021\_reformat.csv" Data collected from a common garden field experiment conducted with eleven weed species and the herbicide dicamba. Note that NA filled in cells of either datasheet indicates data not present or is not relevant. ### Files and variables #### File: DicambaMasterDatasheet2021.csv **Description:** Plant growth and damage data ##### Variables column label description * ID Individual plant id * num.label: front side of the tags on the plants in the field-- every plot is numbered 1-66. All except plot 11 have 13 columns and 6 rows, the counting is left to right top to bottom Plot 11 has 6 rows and 11 columns * ind.label: back side of the tags on all plants in the field-- species name, plot number (1-11), biorep number (1-6) * SPP: Four letter species code * species2: Full scientific name * Plot: plot number 1-11 * PlantingDay: date that seed was planted--for plants seeded on 5-21 this was in the greenhouse, all other days in the field * greenhouseorfield: planted in greenhouse and then transplanted or initially planted seed in the field. * germ.day: data first seen, usually happened around 6-18 when germination began to be recorded. this is in julian days * trans.day: date transplanted if the plant was transplanted. anything with planting day on may 22 was from the greenhouse, all others from a different place in the field * trans: 1 means a transplant from greenhouse and 0 means planted as seed * Survival7/20: 1 if plant is present by 7/13, 0 if absent, assumed dead or never germinated * datefirstflower date flowers first seen in the field to be open in Julians * TRT: control, drift, or full spray * prespray.initials: Initials of person who took pre-spray data * prespraydate: The date the pre-spray measure was taken * pre.spray.leafcount: total number of leaves counted immediately prior to dicamba treatment. This includes deformed or withering leaves, so long as they are still attached to the plant. * pre.spray.leafsize: largest dimension of the biggest leaf measured immediately prior to dicamba treatment. Units are centimeters taken with a ruler. * pre.spray.height: tip of the longest stem to the ground in cm * presprayNotes: relevent notes collected on that day * postspray.48hr.initials: Initials of the person who took postspray data * postspray.48hr.date: Date postspray data was taken * postspray.48hrleafcount: count of total attached leaves at 2 days post spray * postspray.48hrdamagedleaves: count of leaves expressing dicamba damage (curling, yellowing) 2 days post spray * postspray.48hrNotes: Notes from postspray measurement * Notes_7/29: mammalian herbivory in plot 4 * Notes_8/6: mammalian herbivory in plot8 * post.spray.3wkleafcount: total number of leaves counted 3 weeks post dicamba treatment. This includes deformed or withering leaves, so long as they are still attached to the plant. * post.spray3wkdamagedleaves: count of leaves expressing dicamba damage (curling, yellowing) 3 weeks post spray * post.spray.3wkleafsize: largest dimension of the biggest leaf measured 3 weeks post dicamba treatment. Units are centimeters taken with a ruler. * post.spray.3wkheight: tip of the longest stem to the ground in cm * postspray.3wknotes: notes taken at the 3 week post spray collection time * herbivory.photo.initials: initials of person who collected herbivory photos * deformed: 1 or 0 for if new leaves appear deformed while taking herbivory photos * Notes8/17: notes taken during herbivory photos * Notes9/29: herbivory damage in plots 7 and 10 * Seedcount: count of seeds collected throughout the season but estimated, and should not be used. Other datasheet has comprehesive seed counts * Observed6/30: survival taken during germination * Notes6/30: notes taken during germination * Observed7/5: survival taken during germination * Notes7/5: notes taken during germination * Observed7/9: survival taken during germination * OpenFlowerCumulative_2timesaweek: flower count taken 2 times a week for 11 weeks added up * OpenFlowerCumulativeTotal: flower count taken 2 times a week for 11 weeks plus the first 5 rounds of pollinator observation flower counts to add up all total flower counts with extra between 8/19 and 9/1 * Herbivory7/5: herbivory noted during germination NA's in this datasheet indicates lack of relevancy (ie in notes columns) or a missing plant (ie columns recording vegetative traits) #### File: Pollinator\_2021\_reformat.csv **Description:** Pollinator obs data column name description * ID: Plot_IndID, plot number and individual plant id * Round_Number: 1-12 of round of observation * Date: observation date * Plot: plot ID * TRT: the level of dicamba treatment, control vs dicamba * Weather: weather description, added descriptor for being shaded by trees not present in 2019 * StartTime: start of visitation observation * EndTime: end of visitation obervation * VisitationTime: Length of observation in minutes * Location: number in plot, "vicinity" means a pollinator was observed during the abundance count within the plot area not at a specific plant * Target.Nontarget: T=target species, background=volunteer * Species: plant species * Target.Nontarget: identified target plants (those we planted) vs volunteers * NumFlowersOpen: number of open flowers * Abundance: pollinator was present in plot at entrance, a snapshot * Approach: when a pollinator comes close to a flower without visiting * Visit: a foraging visit by a pollinator * notes: notes on pollinator visit/approach counts Note that in Approach/Visit columns, pollinator id's are the following: HB=Honeybee, SB=Sweat bee, TB=True bug, YJ = Yellow jacket, HF=Hover fly, BB = Bumblebee NA's in this datasheet indicates lack of relevancy since the presence of data indicates a visit or approach by a specific pollinator ## Code/software We used the program R (version 4.2.1) to conduct all statistical analyses. Scripts DicambaPollination1-15-25.Rmd, DicambaFieldAnalysis1-15-25.Rmd, and SEM.Rmd accompany this work and provide code for analysis of pollinator abundance and visitation, plant traits, and structural equation modeling linking plant traits and pollinator visits.