DOI: 10.5061/dryad.wwpzgmst6
title: Data from: Insect size responses to climate change vary across elevations according to seasonal timing

description: Body size declines are a common response to warming via both plasticity
 and evolution, but variable size responses have been observed for
 terrestrial ectotherms. We investigate how temperature dependent
 development and growth rates in ectothermic organisms induce variation in
 size responses. Leveraging long-term data for six montane grasshopper
 species spanning 1768 to 3901m, we detect size shifts since ~1960 that
 depend on elevation and species’ seasonal timing. Size shifts have been
 concentrated at low elevations, with the early emerging species (those
 that overwinter as juveniles) increasing in size, while later season
 species are becoming smaller. Interannual temperature variation accounts
 for the size shifts. The earliest season species may be able to take
 advantage of warmer conditions accelerating growth during early spring
 development, whereas warm temperatures may adversely impact later season
 species via mechanisms such as increased rates of energy use or thermal
 stress. Grasshoppers tend to capitalize on warm conditions by both getting
 bigger and reaching adulthood earlier. Our analysis further reinforces the
 need to move beyond expectations of universal responses to climate change
 to consider how environmental exposure and sensitivity vary across
 elevations and life histories.
description: <strong><em>Specimens and
 measurements</em></strong> Grasshoppers
 were field collected, mostly by sweep netting as part of weekly surveys,
 in montane or subalpine sites primarily along the 40th N parallel in
 Boulder County, CO. Historical collections were led by Gordon Alexander,
 with sampling concentrated in 1958-1960. We conducted resurveys with
 sampling concentrated in 2006-2015. The specimens used to measure body
 size are available in the University of Colorado Museum of Natural
 History. Body size was measured as femur length, which
 is the body size metric that can best be compared between museum and
 recent specimens. Femur length is widely used to indicate body size in
 grasshoppers and other insects, due to the ease of measurement and its
 high correlation with body mass. We measured femurs to the nearest one
 hundred of a millimeter using digital calipers. Femur length was estimated
 as the average end to end length of both femurs, which were measured twice
 for most of the specimens. However, a minority of specimens were measured
 to a lesser resolution, had only one femur, or were measured only once.
 Historic specimens were dried whereas modern specimens were measured after
 being stored frozen or were occasionally live when part of other
 experiments. To confirm that femur length was not altered by drying, we
 measured some modern specimens fresh and again following being
 dried. The focal species exhibit additional life
 history and functional differences. The nymphal diapausers (<em>E.
 simplex</em> and<em> X. corallipes)</em>, along
 with <em>A. clavatus </em>and <em>C.
 pellucida,</em> primarily feed on grasses and sedges, while the
 other species are generalists, consuming both grasses and forbs. The
 species differ in dispersal ability (due to wing length differences) and
 lower rates of gene flow result in greater genetic differentiation and
 more potential for local adaptation. <em>Melanoplus
 boulderensis</em> and <em>A. clavatus</em> have short
 wings and are least dispersive. Females of <em>E. simplex</em>
 and<em> X. corallipes</em> have longer wings but tend to be
 poor fliers. Our analysis focuses on 10 sites spanning
 the following elevations: 1768m, 2042m, 2134m, 2317m, 2591m, 3048m, 3414m,
 3505m, 3566m, and 3901m. These sites were chosen because they offered
 sufficiently large historic and recent body size samples for comparison.
 The sites are all grassy meadows, with similar plant communities but
 somewhat denser vegetation at the mid elevation sites.
 <strong><em>Climate
 data</em></strong> Climate data were
 obtained for each specimen based on its site and year of sampling. We
 accessed daily mean temperature data for five weather stations
 corresponding to collection locations (A1: 2195 m, 40.01N, 105.37W; B1:
 2591 m, 40.02N, 105.43W; C1: 3048 m, 40.03N, 105.55W; D1: 3739 m, 40.06N,
 -105.62W; Boulder: 1671 m, 39.99N, 105.27W). The Boulder data were
 accessed from the NOAA Physical Sciences Laboratory (https://psl.noaa.gov/boulder/data/). Data for other sites were accessed from the Niwot Ridge Long-Term Ecological Research program (LTER, https://nwt.lternet.edu/). Data from 1953 to 2008 were accessed from McGuire et al. (2012) and included some regression-based interpolation between weather stations to fill data gaps. Data from 2008 to 2015 were accessed from Buckley et al. (2021) using the same source data interpolation approach. We extended the weather record through 2022 using data from NOAA and the Niwot Ridge LTER site. Following the weather data assembly, data were missing for A1 and B1 from 1970-1986. We interpolated this weather data, again using the interpolation approach of McGuire et al. (2012). For sites without weather data, we used the available climate data most similar in elevation.  We aggregated daily maximum, minimum, and mean temperature data into averages across days of the growing season (March through August, doy 60 to 243) and previous summer (June through August, doy 152 to 243) temperatures. We used temperatures the previous summer since they influence maternal conditions and the development of nymphal diapausing species, which overwinter in a late juvenile stage. We did not examine winter temperatures since most sites have abundant winter snow cover that covers and thermally buffers eggs or nymphs from temperature fluctuations. We examined, but ultimately did not incorporate additional climate metrics including growing degree days available for development and snow depth and timing based on model performance. <strong><em>Phenology</em></strong> We examined how phenology influences body size using the collection date of specimens as well as field surveys. Data from weekly surveys were analyzed for both a historic (1958-1960) and recent (2006-2016) period. We quantified phenology as the day of year when a spline fit to developmental data indicated that the average developmental stage of the sample population was 5.5 (development index ranging from 1: all first instars to 6: all adults; detailed methods in Nufio and Buckley 2019). 
description: # Data from: Insect size responses to climate changes vary across
 elevations according to seasonal timing
 [https://doi.org/10.5061/dryad.wwpzgmst6](https://doi.org/10.5061/dryad.wwpzgmst6) The repository includes the following files: AlexanderBodySize_all.csv: grasshopper body size dataset for the Gordon Alexander collection at the University of Colorado Museum of Natural History. AlexanderBodySize_wClimate.csv: abbreviated grasshopper body size dataset with appended climate data. HopperData_Sept2019.csv: data from grasshopper phenological surveys from Buckley et al (2021). Levy_FemaleGradientDataGrasshopper.csv: reproductive data from Levy and Nufio (2014). NiwotClimateFilled.csv: climate data for study sites. ## Description of the data and file structure Data are described in the AlexanderBodysizeData_Readme.csv file and below. AlexanderBodySize_all.csv | attributeName | attributeLabel | attributeDefinition | storageType | formatString | unit | missingValueCode | | :------------------ | :------------- | :---------------------------------- | :---------- | :---------------- | :--- | :--------------- | | Species | Species | species name with abbreviated genus | character | | | NA | | Sites | Sites | site abbreviation | character | | | NA | | Year | Year | collection year | numeric | YYYY | | NA | | Project information | Project\_info | name of project collecting data | character | | | NA | | Sex | Sex | sex: M or F | character | M, F | | NA | | Specimen Number | Specimen\_No | specimen index within project | numeric | | | NA | | Barcode | Barcode | CU Museum barcode number | numeric | | | NA | | R\_Femur1 | R\_Femur1 | length of 1st right femur | numeric | | mm | NA | | R\_Femur2 | R\_Femur2 | length of 2nd right femur | numeric | | mm | NA | | L\_Femur1 | L\_Femur1 | length of 1st left femur | numeric | | mm | NA | | L\_Femur2 | L\_Femur2 | length of 2nd left femur | numeric | | mm | NA | | Mean Femur | Mean\_Femur | mean femur length | numeric | | mm | NA | | Mass | Mass | mass | numeric | | g | NA | | time | time | time period | character | current, historic | NA | | | elev | elev | site elevation | numeric | | m | NA | AlexanderBodySize_wClimate.csv | attributeName | attributeLabel | attributeDefinition | storageType | formatString | unit | missingValueCode | | :-------------------------- | :------------------ | :----------------------------------------------------------------------------------------------------------------- | :---------- | :----------------- | :------------- | :--------------- | | Species | Species | species name with abbreviated genus | character | | | NA | | Sites | Sites | site abbreviation | character | | | NA | | Year | Year | collection year | numeric | YYYY | | NA | | Project information | Project\_info | name of project collecting data | character | | | NA | | Sex | Sex | sex: M or F | character | M, F | | NA | | Specimen Number | Specimen\_No | specimen index within project | numeric | | | NA | | Barcode | Barcode | CU Museum barcode number | numeric | | | NA | | R\_Femur1 | R\_Femur1 | length of 1st right femur | numeric | | mm | NA | | R\_Femur2 | R\_Femur2 | length of 2nd right femur | numeric | | mm | NA | | L\_Femur1 | L\_Femur1 | length of 1st left femur | numeric | | mm | NA | | L\_Femur2 | L\_Femur2 | length of 2nd left femur | numeric | | mm | NA | | Mean Femur | Mean\_Femur | mean femur length | numeric | | mm | NA | | Mass | Mass | mass | numeric | | g | NA | | time | time | time period | character | current, historic | NA | | | elev | elev | site elevation | numeric | | m | NA | | SpecElevSex | SpecElevSex | concatenation of Species, elev, Sex for indexing | character | | | NA | | Femur anomaly | Femur.anom | femur length anomaly by species, site, sex | numeric | | mm | NA | | ClimSite | ClimSite | site source of climate data | character | | | NA | | Tspr mean | Tspr.mean | mean of daily mean temperature across spring | numeric | | degree Celcius | NA | | Tspr mean anomalie | Tspr.mean.anom | anomaly of mean of daily mean temperature across spring | numeric | | degree Celcius | NA | | Tsum mean | Tsum.mean | mean of daily mean temperature across summer | numeric | | degree Celcius | NA | | Tsum mean anomalie | Tsum.mean.anom | anomaly of mean of daily mean temperature across summer | numeric | | degree Celcius | NA | | Tsum previous mean | Tsum.mean.prev | mean of previous year daily mean temperature across summer | numeric | | degree Celcius | NA | | Tsum previous mean anomalie | Tsum.mean.anom.prev | anomaly of mean of previous year daily mean temperature across summer | numeric | | degree Celcius | NA | | Date Collected | DateCollected | date collected | date | M/D/YY | | NA | | month | month | month | numeric | M | | NA | | day | day | day | numeric | D | | NA | | year | year | year | numeric | YYYY | | NA | | time period | timeperiod | time period | character | current, historic | NA | | | doy\_spec | doy\_spec | day of year of specimen collection | numeric | | | NA | | SpElev | SpElev | concatenation of Species and elev for indexing | character | | | NA | | Tmonth mean | Mean.mo | mean of daily mean temperature across the month before collection | numeric | | degree Celcius | NA | | Tmonth mean anomaly | Tmo.anom | anomaly of mean of daily mean temperature across the month before collection | numeric | | degree Celcius | NA | | Species Timing | SpTiming | seasonal timing of species | character | nymph, early, late | NA | | | Tgs mean | Tgs.mean | mean of daily mean temperature across the growing season (March through August, doy 60 to 243) | numeric | | degree Celcius | NA | | Tgs mean anomaly | Tgs.mean.anom | anomaly of mean of daily mean temperature across the growing season (March through August, doy 60 to 243) | numeric | | degree Celcius | NA | | Tgs previous mean | Tgs.mean.prev | mean of daily mean temperature across the previous growing season (March through August, doy 60 to 243) | numeric | | degree Celcius | NA | | Tgs previous mean anomaly | Tgs.mean.anom.prev | anomaly of mean of daily mean temperature across the previous growing season (March through August, doy 60 to 243) | numeric | | degree Celcius | NA | HopperData_Sept2019.csv | attributeName | attributeLabel | attributeDefinition | storageType | formatString | unit | missingValueCode | | :------------ | :------------- | :------------------------------------------------------- | :---------- | :----------- | :------------- | :--------------- | | ordinal date | ordinal | ordinal date of survey | numeric | | | NA | | species | species | species name | character | | | NA | | in6 | in6 | number of adult individuals | numeric | | | NA | | in5 | in5 | number of 5th instar individuals | numeric | | | NA | | in4 | in4 | number of 4th instar individuals | numeric | | | NA | | in3 | in3 | number of 3rd instar individuals | numeric | | | NA | | in2 | in2 | number of 2nd instar individuals | numeric | | | NA | | in1 | in1 | number of 1st instar individuals | numeric | | | NA | | total | total | total number of individuals | numeric | | | NA | | year | year | year | numeric | YYYY | | NA | | site | site | sites | character | | | NA | | DI | DI | development index | numeric | | | NA | | elev | elev | site elevation | numeric | | m | NA | | spsiteyear | spsiteyear | concatenation of species, site, year for indexing | character | | | NA | | doy\_adult | doy\_adult | doy of year of adulthood for species, site, year | numeric | | degree Celcius | NA | | gdd\_adult | gdd\_adult | growing degree days at adulthood for species, site, year | numeric | | degree Celcius | NA | Levy_FemaleGradientDataGrasshopper.csv | attributeName | attributeLabel | attributeDefinition | storageType | formatString | unit | missingValueCode | | :----------------- | :----------------- | :--------------------------------- | :---------- | :----------- | :--- | :--------------- | | ID | ID | ID from collection | numeric | | | NA | | Species | Species | species | character | | | NA | | Site | Site | site | character | | | NA | | Femur\_mm | Femur\_mm | femur length | numeric | | mm | NA | | ClutchSize | ClutchSize | clutch size | numeric | | | NA | | EggMass | EggMass | egg mass | numeric | | g | NA | | NOvarioles | NOvarioles | number ovarioles | numeric | | | NA | | NFunctOvarioles | NFunctOvarioles | number of functional ovarioles | numeric | | | NA | | PropFunctOvarioles | PropFunctOvarioles | proportion of functional ovarioles | numeric | | | NA | | Elevation\_m | Elevation\_m | elevation | numeric | | m | NA | | log Eggs | logEggs | log number of eggs | numeric | | | NA | | ClutchMass\_g | ClutchMass\_g | clutch mass | numeric | | g | NA | NiwotClimateFilled.csv | attributeName | attributeLabel | attributeDefinition | storageType | formatString | unit | missingValueCode | | :------------ | :------------- | :----------------------------------------------- | :---------- | :----------- | :------------- | :--------------- | | Site | Site | site | character | | | NA | | Year | Year | year | numeric | YYYY | | NA | | Max | Max | mean of max daily temperature | numeric | | degree Celcius | NA | | Mean | Mean | mean of mean daily temperature | numeric | | degree Celcius | NA | | Min | Min | mean of min daily temperature | numeric | | degree Celcius | NA | | filled | filled | filled? 0: no; 1: yes | numeric | 0, 1 | | NA | | Seas | Seas | season (spring, summer, gs: growing season) | character | | | NA | | SiteYr | SiteYr | concatenation of site, year for indexing | character | | | NA | | SiteSeas | SiteSeas | concatenation of site, season for indexing | character | | | NA | | SiteYrSeas | SiteYrSeas | concatenation of site, year, season for indexing | character | | | NA | | Max.anom | Max.anom | anomaly of mean of max daily temperature | numeric | | degree Celcius | NA | | Min.anom | Min.anom | anomaly of mean of min daily temperature | numeric | | degree Celcius | NA | | Mean.anom | Mean.anom | anomaly of mean of mean daily temperature | numeric | | degree Celcius | NA | ## Sharing/Access information Some data were derived from the following sources: * Buckley, L. B., Graham, S. I. & Nufio, C. R. Grasshopper species’ seasonal timing underlies shifts in phenological overlap in response to climate gradients, variability and change. Journal of Animal Ecology 90, 1252–1263 (2021). [https://doi.org/10.1111/1365-2656.13451](https://doi.org/10.1111/1365-2656.13451) Dryad Digital Repository [https://doi.org/10.5061/dryad.9ghx3ffgb](https://doi.org/10.5061/dryad.9ghx3ffgb) * Levy, R. A. & Nufio, C. N. Dispersal potential impacts size clines of grasshoppers across an elevation gradient. *Oikos* **124**, 610–619 (2014). [https://doi.org/10.1111/oik.01615](https://doi.org/10.1111/oik.01615) ## Code/Software R code is uploaded for creating figures and analysis: BodysizeFigures_ms.R. Data processing and code development is documented at [https://github.com/lbuckley/HopperBodysize](https://github.com/lbuckley/HopperBodysize).