DOI: 10.5061/dryad.3n5tb2rjk
title: Timing of short-term drought structures plant-herbivore dynamics

description: Drought is an important stressor that affects plant growth, survival and
 physiology and, through plant responses, alters plant-herbivore
 interactions and herbivore population dynamics. Short-term drought can
 occur at different times during a growing season, affecting herbivore
 populations and plants at various stages of development and growth. As
 phenology influences drought response, drought timing could strongly
 structure plant-herbivore interactions. We grew common milkweed plants
 with or without its dominant aphid herbivore, allowing both plants and
 herbivore populations to develop over time as in a typical growing season.
 To determine how drought timing affects plants and aphid populations, we
 applied short-term (1 week) drought at different times. Plants and aphids
 were sensitive to drought timing, with a few weeks difference shifting the
 effects of drought from minimal to causing massive declines in plant
 growth, plant survival and herbivore population density. Aphid herbivory
 added to or overrode drought consequences in plants, with different plant
 fitness components responding distinctly to herbivory. Drought timing also
 affected whether plant and herbivore responses were parallel or divergent,
 suggesting that shifts in the seasonal timing of drought have the
 potential to disrupt plant-herbivore interactions and affect the larger
 ecological community. Our results show drought timing has important and
 disparate consequences for herbivores and their host plants and indicates
 the necessity of considering phenology and timing in assessing drought
 response.
description: This DataS1readme.txt file was generated on 2021-10-19 by Ruiping
 Luo. GENERAL INFORMATION Title of
 Dataset: Timing of short-term drought structures plant-herbivore
 dynamics Author Information<br>     Principal
 Investigator <br>         Name: Ruiping Luo<br>       
  Institution: University of Toronto    <br>         Email:
 ruiping.luo@mail.utoronto.ca   
  Co-investigator <br>         Name: Benjamin Gilbert<br>   
      Institution: University of Toronto<br>         Email:
 benjamin.gilbert@utoronto.ca Date of data collection:
 2019-07-10 to 2019-08-28 Geographic location of data
 collection: Toronto, Ontario, Canada Funding sources
 that supported the collection of the data: This research was supported by
 funding from Natural Sciences and Engineering Research Council of
 Canada <br> DATA & FILE
 OVERVIEW File List: <br> DataS1.xlsx - Main data
 set<br> CodeS1.R - R code for data analysis in manuscript<br>
 Supplementary.R - R code for data analysis in supplementary
 materials Relationship between files: CodeS1.R and
 Supplementary.R require input from DataS1.xlsx for analysis
 <br> DATA-SPECIFIC INFORMATION FOR: DataS1.xlsx (Sheet
 title: Photosynthesis) Number of variables: 6
 Number of rows: 280 Variable List: <br>
 Plant - Number identification of individual plants<br> Block -
 Blocks sorted by plant size (1=smallest, 10=largest)<br> Treatment -
 Drought treatment, applied as 1-week without water addition at various
 times throughout a growing season (0=control)<br> Date - Date of
 data collection<br> Day - Day of experiment<br> Average -
 Average change in carbon dioxide in micromoles per meter squared per
 second (umol m^-2 s^-1) DATA-SPECIFIC INFORMATION FOR:
 DataS1.xlsx (Sheet title: Plants) Number of variables:
 40 Number of rows: 100 Variable
 List: <br> Plant - Number identification of individual
 plants<br> Block - Blocks sorted by plant size (1=smallest,
 10=largest)<br> Treatment - Drought treatment, applied as 1-week
 without water addition at various times throughout a growing
 season (0=control)<br> Aphids - Presence of aphids on plants (0=no
 aphids, 1=aphids introduced)<br> nLeaf - Initial number of leaves
 prior to experiment<br> yLeaf - Final number of yellow leaves
 following experiment<br> gLeaf - Final number of green leaves
 following experiment<br> Height - Height of plant above soil
 surface<br> L1, L2, L3 - Length of youngest, second youngest and
 third youngest leaf prior to experiment in centimeters (cm)<br> W1,
 W2, W3 - Width of youngest, second youngest and third youngest leaf prior
 to experiment in centimeters (cm)<br> Latex - Weight of exuded latex
 in grams (g)<br> Trichomes - Density of trichomes on tip of second
 youngest leaf <br> State - State of plant following experiment
 (0=dead, 1=live)<br> Livemass - Wet biomass of aboveground plant
 matter considered living following experiment in grams (g)<br>
 Deadmass - Wet biomass of aboveground plant matter considered dead
 following experiment in grams (g)<br> Rootmass - Wet biomass of
 belowground plant matter following experiment in grams (g)<br>
 Leafmass1, Leafmass2, Leafmass3 - Wet biomass of youngest, second youngest
 and third youngest leaf following experiment in grams (g)<br>
 Livedry - Dry biomass of aboveground plant matter considered living
 following experiment in grams (g)<br> Deaddry - Dry biomass of
 aboveground plant matter considered dead following experiment in grams
 (g)<br> Rootdry - Dry biomass of belowground plant matter following
 experiment in grams (g)<br> Litter - Biomass of leaf litter
 following experiment in grams (g)<br> Leafdry1, Leafdry2, Leafdry3 -
 Dry biomass of youngest, second youngest and third youngest leaf following
 experiment in grams (g)<br> Area1, Area2, Area3 - Area of youngest,
 second youngest and third youngest leaf following experiment in
 centimeters squared (cm^2)<br> L1a, L2a, L3a, - Length of youngest,
 second youngest and third youngest leaf following experiment in
 centimeters (cm)<br> W1a, W2a, W3a, - Width of youngest, second
 youngest and third youngest leaf following experiment in centimeters
 (cm)<br> Mortality - Day plant was first categorized as
 dead <br> DATA-SPECIFIC INFORMATION FOR:
 DataS1.xlsx (Sheet title: Survival) Number of
 variables: 6 Number of rows: 1300
 Variable List: <br> Plant - Number identification of
 individual plants<br> Block - Blocks sorted by plant size
 (1=smallest, 10=largest)<br> Treatment - Drought treatment, applied
 as 1-week without water addition at various times throughout a growing
 season (0=control)<br> Aphids - Presence of aphids on plants (0=no
 aphids, 1=aphids introduced)<br> Day - Day of experiment<br>
 State - State of plant following experiment (0=dead, 1=live)
 <br> DATA-SPECIFIC INFORMATION FOR: DataS1.xlsx (Sheet
 title: Aphids) Number of variables: 7
 Number of rows: 550 Variable List: <br>
 Plant - Number identification of individual plants<br> Block -
 Blocks sorted by plant size (1=smallest, 10=largest)<br> Treatment -
 Drought treatment, applied as 1-week without water addition at various
 times throughout a growing season (0=control)<br> Day - Day of
 experiment<br> Obs - Observation number for aphid counts<br>
 Winged - Density of winged aphids (aphids per plant)<br> Unwinged -
 Density of unwinged aphids (aphids per plant)