DOI: 10.5061/dryad.v15dv427d
title: Local thermal extremes shape the nature of herbivore plasticity that controls plant communities

description: Prevailing views hold that species’ physiological plasticity may confer
 resilience to warming, but its importance varies across climatic gradients
 (e.g., latitude). Yet, along such gradients local species populations may
 experience fine-scale spatially heterogeneous variation in extreme
 temperatures and other ecological stressors. We show that at four Cool
 (mean diel maximum 29.83°C) and four Warm (mean diel maximum 31.51°C)
 sites, interspersed as a spatial mosaic throughout a 26,200 km2 area,
 local herbivore populations responded differently to stress from
 experimental warming (ambient, warmed) and predation (presence, absence).
  Cool and Warm site herbivore populations utilized different
 combinations of behavioral and physiological plasticity to cope with the
 dual stressors that were contingent on local temperature extremes. These
 unique plastic responses had divergent cascading effects on the plant
 community. Our results suggest that paying attention to local population
 variation can enhance the ability to predict the fate of natural
 communities under environmental change.  
description: <em>Field experiment design</em>
 For each grasshopper population, we factorially crossed spider
 predation risk (present, absent) and experimental warming (warming,
 ambient) using experimental mesocosm cages in the field. Each cylindrical
 cage (0.25 m<sup>2</sup> × 1.0 m H) was constructed using
 vinyl-coated garden wire fencing; the sides and tops of each cage were
 covered with insect screening. We deployed 20 cages (each separated by at
 least 1 m) within each field over naturally growing vegetation. We
 selected cage locations to ensure they all contained a similar initial
 composition of grass and <em>Solidago</em>, which was verified
 by measuring initial percent cover of grass and
 <em>Solidago</em>. We created experimental
 warming treatments by wrapping the sides of assigned cages with
 translucent plastic sheeting (4 mm Film-Gard, Covalence Plastics,
 Minneapolis, MN, USA); the bottom 10 cm of the cages was left unwrapped to
 permit airflow. Experimental warming does not increase temperatures
 consistently over 24 hours: warming occurred during the day and dissipated
 at night, resulting in the simultaneous change of mean diel mean
 temperature (+0.67 °C), mean diel maximum temperature (+2.79 °C), mean
 diel minimum temperature (-0.27 °C), and mean diel coefficient of
 variation in temperature (+15%; P &lt; 0.05 in all cases). While
 wrapping could influence plant growth and development by altering wind and
 humidity, prior work indicates that end-of-season plant biomass was
 unaffected directly by such experimental warming treatments.
 From late June to early July, we cleared cages of all arthropods
 before randomly assigning spider predators and grasshoppers to the various
 treatment cages. We then stocked predator treatment cages with local
 spiders at natural field densities (1 spider per cage). In mid-July, we
 stocked all cages with local third-instar grasshoppers at natural field
 densities (5 grasshoppers per cage). One week after stocking, we replaced
 any grasshoppers that experienced mortality due to handling stress.
 Thereafter, we allowed grasshoppers to grow and develop under their
 respective treatment combinations until late September to early
 October. <em>Geographic variation in climatic
 conditions among local populations</em>
 Populations were selected to encompass a range of the thermal
 regimes (mean temperature, variability, and extremes) present in New
 England. Remotely sensed data may not capture fine spatial-scale thermal
 regimes experienced by grasshoppers within a local field site, therefore
 we recorded temperature hourly within the vegetation canopy at 60 cm above
 the soil with temperature loggers placed within multiple* *experimental
 field cages at every site (MX2201, Onset Corporation, Bourne, MA, USA). We
 included data from temperature loggers deployed in cages for the present
 study and those deployed in a parallel field experiment that utilized the
 same 8 populations in identical cages to better resolve and quantify
 variation in thermal regimes within local population sites. We calculated
 mean diel mean temperature, mean diel coefficient of variation in
 temperature, and mean diel temperature extremes for each logger at a
 population’s field site. We then used GLMs to compare metrics with Site
 type as a fixed effect and population as a random effect nested within
 Site type (all conducted in R v.4.2.2 with lme4 v.1.1.31 , lmerTest
 v.3.1.3, DHARMa v.0.4.6, and MuMIn v.1.48.4 packages).
 We tested the effect of experimental warming treatments on cage
 temperatures for each local population by analyzing temperature data from
 loggers deployed in ‘warmed’ and ‘ambient’ treatments with GLMs that
 compared the mean diel maximum, mean and minimum temperature, and mean
 diel coefficient of variation in temperature among populations and between
 Site types. Site type and experimental warming were considered fixed
 effects, and population was considered a random effect nested within Site
 type. <em>Behavioral
 Plasticity</em> During sunny days in mid-August,
 we assayed how grasshoppers from different populations responded
 behaviorally to predation risk and experimental warming by recording their
 habitat use within benchtop terraria in their native fields. Terraria (30
 cm W × 40 cm L × 90 cm H) had a rectangular plywood base with sides and
 tops enclosed with fiberglass insect screening. Terraria were planted with
 1-2 <em>Solidago</em> (60 cm H) and grasses grown in a
 greenhouse. We superimposed a 4 × 4 cm measurement grid on one face (84 cm
 × 40 cm) of each terrarium to allow measurement of the vertical position
 of grasshoppers in the canopy at each sampling time. We wrapped terraria
 assigned to experimental warming treatments with clear, thin plastic
 sheeting to generate warming. We recorded the temperature in a subset of
 the terraria every 5 minutes (MX2202 loggers from Onset Corporation,
 Bourne, MA, USA) at a canopy height of 60 cm. At each
 field site, we transferred 2-3 grasshoppers from our previously
 established field experiment cages to a benchtop terrarium with the same
 experimental warming and predation risk treatments of sourced
 grasshoppers. For the predation risk treatment, we caught spiders from
 each respective field; however, due to a spider population crash in one of
 our VT populations, we sourced spiders from our second VT population.
 After stocking, we allowed the grasshoppers and spiders to acclimate to
 the terraria overnight and resume normal behaviors. Every 20 minutes
 between 09:00-17:40, we recorded the vertical position of each grasshopper
 within each terrarium. After completing habitat use measurements,
 grasshoppers were returned to their respective field experiment cages and
 spiders were confirmed to be alive and mobile in every predation risk
 terrarium. During the behavioral assays in field
 terraria, experimental warming raised mean temperatures by 5.99 °C,
 maximum temperature by 7.25 °C, and minimum temperatures by 3.17 °C (P
 &lt; 0.05 in all cases). Experimental warming also increased the
 coefficient of variation in temperature by 13%, but this trend was not
 significant (P = 0.0831). The influence of experimental warming on
 temperatures did not differ significantly among Site types (P &gt;
 0.05 in all cases). The effects of experimental warming were larger in the
 terraria than those in our field cages because we only assessed behavior
 on clear, sunny days, whereas field loggers within experimental cages
 integrated weather conditions over the whole season. We tested for
 behavioral plasticity by analyzing the percent change in mean daily
 vertical position within benchtop terraria from ambient baseline
 conditions with GLMs that considered predation risk and Site type as fixed
 effects with population as a random effect nested within Site
 type. <em>Physiological
 Plasticity</em> From late September to early
 October, we randomly selected one grasshopper from every treatment cage
 that had surviving grasshoppers and grouped them according to their
 treatment of origin (i.e., each factorial combination of experimental
 warming and predation risk). Grasshoppers were immediately transported to
 the laboratory at Yale University where their thermal performance was
 measured as mass specific respiration rate at 25°C, 30°C, and
 35°C. We evaluated the thermal performance of
 grasshoppers from different populations and rearing treatments, by
 measuring  the mass specific CO<sub>2</sub> respiration of
 grasshoppers across a 10°C gradient in temperature. We measured the
 respiration rates of grasshoppers at 25°C, 30°C, and 35°C as a metric of
 physiological stress because respiration integrates stress induced by both
 temperature and predation risk. After being collected in the field,
 grasshoppers were kept in an environmental control chamber (Percival
 Scientific, Inc., Perry, IA) at ~ 22°C with constant light levels and 50%
 relative humidity. Grasshoppers were given an <em>ad
 libitum</em> supply of water and no food for at least 24 hours after
 collection to put them in a post absorptive state. Just before beginning
 respiration rate measurements, we weighed (g) each grasshopper to allow
 calculation of their mass-specific respiration rate. We measured
 respiration as the volume of CO<sub>2</sub> exhaled by
 grasshoppers with a Qubit S-151 infrared CO2 analyzer (Q-S151 model, 1 ppm
 resolution: Qubit Biology Inc., Kingston, Ontario, Canada) after scrubbing
 the air of water vapor. We used an incurrent flow rate of ~ 110mL/min. We
 measured respiration at 25°C and increased temperature sequentially to
 30°C and then 35°C with the Qubit gas switching system in the 8 tube stop
 flow arrangement. In this arrangement, we used the following parameters:
 Stop Time = 14 minutes, Dwell Time = 2 minutes, Delay Short = 0.2 minutes,
 Delay Long = 1.5 minutes, Event Time = 0.5 minutes. We decided on these
 intervals to avoid saturating the CO<sub>2</sub> analyzer, to
 produce repeatable results for an individual grasshopper, and to manage
 flow constraints of the system. In order to avoid saturating the system
 when assessing respiration, we used Airgas Ultra Zero Grade Air. Working
 with air of a known CO<sub>2</sub> concentration improved the
 accuracy of our measurements and allowed us to extend dwell times without
 the risk of saturating the CO<sub>2</sub> analyzer. We allowed
 grasshoppers to acclimate to each temperature for 32 minutes prior to
 measurement. We tested for physiological plasticity by
 analyzing the percent change in the mass specific respiration rates of
 grasshoppers relative to baseline ambient conditions using GLMs that
 considered predation risk, Site type (i.e., Cool vs Warm), and assay
 temperature (25°C, 30°C, or 35°C) as fixed effects and population as a
 random effect nested within Site type. To account for repeated measures on
 individual grasshopper across all three temperature treatments, we also
 included ‘individual’ as a random effect nested within each unique
 combination of population, predation risk, and Site type.
 <em>Survival</em> At the end of
 the season, we tested for survival differences among grasshopper
 populations by analyzing the percent change in grasshopper counts from
 baseline ambient conditions with GLMs that considered predation risk and
 Site type as fixed effects and population as a random effect nested within
 Site type. <em>Geographic variation in the link
 between grasshopper trait plasticity and community-level
 impacts</em> At each field site, we removed all
 above-ground plant biomass within each experimental cage. Because
 grasshopper herbivory can reduce the biomass of grass and
 <em>Solidago</em>, we sorted all plant biomass from each cage
 by <em>Solidago</em> and grass. <em>Solidago</em>
 and grass samples were weighed after drying for 48 hours at 60°C. Cool
 sites and Warm sites did not differ with respect to initial
 <em>Solidago</em> cover, initial grass cover, or precipitation
 during the experiment (P&gt;0.05 in all cases; 800
 m<sup>2</sup> resolution precipitation from the PRISM Climate
 Group; http://www.prism.oregonstate.edu). We evaluated the impacts of grasshoppers on their local plant community by testing for treatment effects on end-of-season <em>Solidago</em> biomass and grass biomass using GLMs that considered experimental warming, predation risk, and Site type as fixed effects and population as a random effect nested within Site type. To meet the assumptions of GLMs, <em>Solidago</em> biomass data was log<sub>(10)</sub> transformed before analysis.
description: # Local thermal extremes shape the nature of herbivore plasticity that
 controls plant communities
 [https://doi.org/10.5061/dryad.v15dv427d](https://doi.org/10.5061/dryad.v15dv427d) ## Description of the data and file structure The dataset contains 12 comma separated value files which encompass all of the data used in the statistical analyses for this manuscript. These files consist of climate data, measures of grasshopper (*Melanoplus femurrubrum*) plasticity, and plant community biomass. The climate data consists of *in situ* temperature measurements and remotely sensed precipitation data used to (1) characterize sites, (2) determine the influence of experimental warming on thermal regimes, and (3) record weather during behavioral assays. The grasshopper plasticity data measures how experimental warming altered (1) grasshopper canopy height, (2) grasshopper respiration rates, and (3) grasshopper survival. The plant community impact data consists of measures of initial conditions and end season plant biomass to quantify how grasshopper plasticity may have altered the plant surrounding community. File descriptions and column definitions are provided below. ### Files and variables **File: Baker_2022_All_Ambient_Loggers_CSV.csv** **Description:** Includes the daily maximum temperature, daily mean temperature, daily minimum temperature, daily coefficient of variation in temperature, and daily range in temperature recorded by each temperature logger in all ambient cages at a site (MX2201, Onset Corporation, Bourne, MA, USA). We included data from temperature loggers deployed in cages for the present study and those deployed in a parallel field experiment that utilized the same 8 populations in identical cages to better resolve thermal regimes within local population sites. **Variables** * **Site Type:** Denotes whether the local population’s field site experienced high daily maximum temperatures (Warm sites) or low daily maximum temperatures (Cool sites). * **Population:** Denotes the source population and rearing site of grasshoppers. Population codes are abbreviated names of each site: DC= Dartmouth College, FN= Flanders Nature Center, HF= Harvard Forest, MC= Middlebury College, SC= Smith College, SP= Saint Paul’s School,  UP = Upland Park, YM= Yale-Myers Forest. * **Logger:** Denotes each unique temperature logger used in field cages. * **Latitude:** Denotes the latitude of the site. * **Longitude:** Denotes the longitude of the site. * **Daily Max:** The daily maximum temperature (°C) over the course of the field experiment. * **Daily Mean:** The daily mean temperature (°C) over the course of the field experiment * **Daily Min:** The daily minimum temperature (°C) over the course of the field experiment. * **Daily Coeff:** The daily coefficient of variation in temperature over the course of the field experiment. * **Daily Range:** The daily range in temperature (°C) over the course of the field experiment. **File: Baker_2022_PRISM_Precipitation_CSV.csv** **Description:** The mean daily precipitation at sites throughout the field experiment. **Variables** * **Site Type:** Denotes whether the local population’s field site experienced high daily maximum temperatures (Warm sites) or low daily maximum temperatures (Cool sites). * **Population:** Denotes the source population and rearing site of grasshoppers. Population codes are abbreviated names of each site: DC= Dartmouth College, FN= Flanders Nature Center, HF= Harvard Forest, MC= Middlebury College, SC= Smith College, SP= Saint Paul’s School,  UP = Upland Park, YM= Yale-Myers Forest. * **Precipitation:** The mean daily precipitation (mm) at each site at an 800m2 resolution provided by PRISM Climate Group (URL: [http://www.prism.oregonstate.edu](http://www.prism.oregonstate.edu)) * **Elevation:** The elevation of each site (m asl) **File: Baker_2022_Experimental_Warming_Loggers_CSV.csv** **Description:** Includes the daily maximum temperature, daily mean temperature, daily minimum temperature, daily coefficient of variation in temperature, and daily range in temperature recorded by each temperature logger during the field experiment under either ambient or experimentally warmed conditions (MX2201, Onset Corporation, Bourne, MA, USA). **Variables** * **Site Type:** Denotes whether the local population’s field site experienced high daily maximum temperatures (Warm sites) or low daily maximum temperatures (Cool sites). * **Population:** Denotes the source population and rearing site of grasshoppers. Population codes are abbreviated names of each site: DC= Dartmouth College, FN= Flanders Nature Center, HF= Harvard Forest, MC= Middlebury College, SC= Smith College, SP= Saint Paul’s School,  UP = Upland Park, YM= Yale-Myers Forest. * **Warming:** Denotes whether the field cage and associated temperature logger was subjected to natural (ambient) or experimental warming (warmed) conditions. * **Logger:** Denotes each unique temperature logger used in field cages. * **Daily Max:** The daily maximum temperature (°C) over the course of the field experiment. * **Daily Mean:** The daily mean temperature (°C) over the course of the field experiment * **Daily Min:** The daily minimum temperature (°C) over the course of the field experiment. * **Daily Coeff:** The daily coefficient of variation in temperature over the course of the field experiment. * **Daily Range:** The daily range in temperature (°C) over the course of the field experiment. **File: Baker_2022_Behavior_Loggers_CSV.csv** **Description:** Includes the maximum temperature, minimum temperature, mean temperature, coefficient of variation in temperature, and range in temperature recorded by each temperature logger during behavioral assays of grasshopper populations (MX2202, Onset Corporation, Bourne, MA, USA).  **Variables** * **Site Type:** Denotes whether the local population’s field site experienced high daily maximum temperatures (Warm sites) or low daily maximum temperatures (Cool sites). * **Population:** Denotes the source population and rearing site of grasshoppers. Population codes are abbreviated names of each site: DC= Dartmouth College, FN= Flanders Nature Center, HF= Harvard Forest, MC= Middlebury College, SC= Smith College, SP= Saint Paul’s School,  UP = Upland Park, YM= Yale-Myers Forest. * **Warming:** Denotes whether the behavioral terrarium and associated logger was subjected to natural (ambient) or experimental warming (warmed) conditions during behavioral assays. * **Logger:** Denotes each unique temperature logger used in terrarium. * **Max:** The maximum temperature (°C) recorded during the behavioral assay. * **Mean:** The mean temperature (°C) recorded during the behavioral assay. * **Min:** The minimum temperature (°C) recorded during the behavioral assay. * **Coeff:** The coefficient of variation in temperature during the behavioral assay. * **Range:** The range in temperature (°C) during the behavioral assay. **File: Baker_2022_Behavior_Delta_CSV.csv** **Description:** Includes the percent change in canopy height induced by experimental warming relative to baseline ambient conditions. **Variables** * **Site Type:** Denotes whether the local population’s field site experienced high daily maximum temperatures (Warm sites) or low daily maximum temperatures (Cool sites). * **Population:** Denotes the source population and rearing site of grasshoppers. Population codes are abbreviated names of each site: DC= Dartmouth College, FN= Flanders Nature Center, HF= Harvard Forest, MC= Middlebury College, SC= Smith College, SP= Saint Paul’s School,  UP = Upland Park, YM= Yale-Myers Forest. * **Predation:** Denotes whether grasshoppers were reared in the presence (Predator) or absence (No Predator) of *Pisaurina spp.* throughout the experiment and during behavioral assays. * **Terrarium:** Denotes the terrarium within which grasshopper behavior was assessed. * **Delta Behavior:** The percent change in canopy height caused by experimental warming relative to baseline ambient conditions. **File: Baker_2022_Behavior_CSV.csv** **Description:** Includes the mean daily canopy height (cm) of grasshoppers reared under different experimental treatments. **Variables** * **Site Type:** Denotes whether the local population’s field site experienced high daily maximum temperatures (Warm sites) or low daily maximum temperatures (Cool sites). * **Population:** Denotes the source population and rearing site of grasshoppers. Population codes are abbreviated names of each site: DC= Dartmouth College, FN= Flanders Nature Center, HF= Harvard Forest, MC= Middlebury College, SC= Smith College, SP= Saint Paul’s School,  UP = Upland Park, YM= Yale-Myers Forest. * **Warming:** Denotes whether grasshoppers were reared under natural (ambient) or experimental warming (warmed) conditions throughout the experiment and during behavioral assays. * **Predation:** Denotes whether grasshoppers were reared in the presence (Predator) or absence (No Predator) of *Pisaurina spp.* throughout the experiment and during behavioral assays. * **Terrarium:** Denotes the terrarium within which grasshopper behavior was assessed. * **Mean Height:** The mean height (cm) of all grasshoppers within a single terrarium. **File: Baker_2022_Physiology_Delta_CSV.csv** **Description:** Includes the percent change in mass specific respiration rate induced by an experimentally warmed rearing environment relative to baseline ambient conditions at 25°C, 30°C, and 35°C. **Variables** * **Site Type:** Denotes whether the local population’s field site experienced high daily maximum temperatures (Warm sites) or low daily maximum temperatures (Cool sites). * **Population:** Denotes the source population and rearing site of grasshoppers. Population codes are abbreviated names of each site: DC= Dartmouth College, FN= Flanders Nature Center, HF= Harvard Forest, MC= Middlebury College, SC= Smith College, SP= Saint Paul’s School,  UP = Upland Park, YM= Yale-Myers Forest. * **Predation:** Denotes whether grasshoppers were reared in the presence (Predator) or absence (No Predator) of *Pisaurina spp.* throughout the experiment. * **Temperature**: Denotes the assay temperature at which grasshopper mass specific respiration rate was measured (25°C, 30°C, or 35°C). * **Cage:** Denotes the field cage from which the grasshopper was collected. * **Individual:** Denotes each unique grasshopper measured. * **Delta Respiration:** The percent change in mass specific respiration rate induced by an experimentally warmed rearing environment relative to baseline ambient conditions. **File: Baker_2022_Physiology_CSV.csv** **Description:** Includes the mass specific respiration rate (µl of CO2 min-1g-1) at 25°C, 30°C, and 35°C for grasshoppers reared in the field under different experimental treatments. **Variables** * **Site Type:** Denotes whether the local population’s field site experienced high daily maximum temperatures (Warm sites) or low daily maximum temperatures (Cool sites). * **Population:** Denotes the source population and rearing site of grasshoppers. Population codes are abbreviated names of each site: DC= Dartmouth College, FN= Flanders Nature Center, HF= Harvard Forest, MC= Middlebury College, SC= Smith College, SP= Saint Paul’s School,  UP = Upland Park, YM= Yale-Myers Forest. * **Warming:** Denotes whether grasshoppers were reared under natural (ambient) or experimental warming (warmed) conditions throughout the experiment. * **Predation:** Denotes whether grasshoppers were reared in the presence (Predator) or absence (No Predator) of *Pisaurina spp.* throughout the experiment. * **Temperature**: Denotes the assay temperature at which grasshopper mass specific respiration rate was measured (25°C, 30°C, or 35°C). * **Cage:** Denotes the field cage from which the grasshopper was collected. * **Individual:** Denotes each unique grasshopper measured. * **Mass Specific Respiration:** The mass specific respiration rate (µl of CO2 min-1g-1) of each grasshopper at a given assay temperature. **File: Baker_2022_Survival_Delta_CSV.csv** **Description:** Includes the percent change in grasshopper survival induced by experimental warming relative to baseline ambient conditions. **Variables** * **Site Type:** Denotes whether the local population’s field site experienced high daily maximum temperatures (Warm sites) or low daily maximum temperatures (Cool sites). * **Population:** Denotes the source population and rearing site of grasshoppers. Population codes are abbreviated names of each site: DC= Dartmouth College, FN= Flanders Nature Center, HF= Harvard Forest, MC= Middlebury College, SC= Smith College, SP= Saint Paul’s School,  UP = Upland Park, YM= Yale-Myers Forest. * **Predation:** Denotes whether grasshoppers were reared in the presence (Predator) or absence (No Predator) of *Pisaurina spp.* throughout the experiment. * **Cage:** Denotes the field cage in which grasshoppers were reared. * **Delta Survival:** The percent change in survival caused by experimental warming relative to baseline ambient conditions. * **Notes:** In one instance, a *Pisaurina spp. *was found in a cage assigned to receive no predators. Therefore, we treated this cage as a predator cage for our analyses. **File: Baker_2022_Survival_CSV.csv** **Description:** Includes the grasshopper survival within each experimental cage at the end of the field season. **Variables** * **Site Type:** Denotes whether the local population’s field site experienced high daily maximum temperatures (Warm sites) or low daily maximum temperatures (Cool sites). * **Population:** Denotes the source population and rearing site of grasshoppers. Population codes are abbreviated names of each site: DC= Dartmouth College, FN= Flanders Nature Center, HF= Harvard Forest, MC= Middlebury College, SC= Smith College, SP= Saint Paul’s School,  UP = Upland Park, YM= Yale-Myers Forest. * **Warming:** Denotes whether grasshoppers were reared under natural (ambient) or experimental warming (warmed) conditions throughout the experiment. * **Predation:** Denotes whether grasshoppers were reared in the presence (Predator) or absence (No Predator) of *Pisaurina spp.* throughout the experiment. * **Cage:** Denotes the field cage in which grasshoppers were reared. * **Grasshopper Survival Count:** The number of surviving grasshoppers at the end of the field experiment * **Grasshopper Survival Proportion:** The proportion of grasshoppers surviving at the end of the field experiment. * **Notes:** In one instance, a *Pisaurina spp.* was found in a cage assigned to receive no predators. Therefore, we treated this cage as a predator cage for our analyses. **File: Baker_2022_Community_Data_CSV.csv** **Description:** Includes initial conditions and end season plant biomass of field cages stocked with grasshoppers under experimental warming (ambient, warmed) and predation risk (absent, present) treatments. **Variables** * **Site Type:** Denotes whether the local population’s field site experienced high daily maximum temperatures (Warm sites) or low daily maximum temperatures (Cool sites). * **Population:** Denotes the source population and rearing site of grasshoppers. Population codes are abbreviated names of each site: DC= Dartmouth College, FN= Flanders Nature Center, HF= Harvard Forest, MC= Middlebury College, SC= Smith College, SP= Saint Paul’s School,  UP = Upland Park, YM= Yale-Myers Forest. * **Warming:** Denotes whether grasshoppers were reared under natural (ambient) or experimental warming (warmed) conditions throughout the experiment. * **Predation:** Denotes whether grasshoppers were reared in the presence (Predator) or absence (No Predator) of *Pisaurina spp.* throughout the experiment. * **Cage:** Denotes the field cage from which plant biomass was collected. * **Initial Solidago Cover:** Initial percent cover of *Solidago* within a cage prior the application of experimental treatments. * **Solidago Biomass:** End season *Solidago* biomass (g). * **log(Solidago Biomass):** Log10 transformed end season *Solidago* biomass (g). * **Initial Grass Cover:** Initial percent cover of grass (primarily *Poa spp.*) within a cage prior to the application of experimental treatments. * **Grass Biomass:** End season grass (primarily *Poa spp.*) biomass (g). * **Notes:** In one instance, a *Pisaurina spp.* was found in a cage assigned to receive no predators. Therefore, we treated this cage as a predator cage for our analyses. **File: Baker_2024_Vegetation_Warming_CSV** **Description:** Includes initial conditions and end season plant biomass of field cages without any grasshoppers under experimental warming (ambient, warmed) treatments. **Variables** * **Site Type:** Denotes whether the local population’s field site experienced high daily maximum temperatures (Warm sites) or low daily maximum temperatures (Cool sites). * **Population:** Denotes the source population and rearing site of grasshoppers. Population codes are abbreviated names of each site: DC= Dartmouth College, FN= Flanders Nature Center, MC= Middlebury College, SP= Saint Paul’s School,  UP = Upland Park, YM= Yale-Myers Forest. * **Warming:** Denotes whether grasshoppers were reared under natural (ambient) or experimental warming (warmed) conditions throughout the experiment. * **Cage:** Denotes the field cage from which plant biomass was collected. * **Initial Solidago Cover:** Initial percent cover of *Solidago* within a cage prior the application of experimental treatments. * **Solidago Biomass:** End season *Solidago* biomass (g). * **log(Solidago Biomass):** Log10 transformed end season *Solidago* biomass (g). * **Initial Grass Cover:** Initial percent cover of grass (primarily *Poa spp.*) within a cage prior to the application of experimental treatments. * **Grass Biomass:** End season grass (primarily *Poa spp.*) biomass (g). ## Access information Precipitation data was derived from the following source: * Precipitation data from the PRISM Climate Group, Oregon State University (2022) [http://www.prism.oregonstate.edu](http://www.prism.oregonstate.edu)