DOI: 10.5061/dryad.4qrfj6qh1
title: Wing lengths of three Arctic butterfly species decrease as summers warm in Alaska

description: Climate warming can cause arthropods to express plastic and/or evolved
 changes in morphology. Previous studies have demonstrated that body sizes
 of Arctic butterflies are influenced by the temperatures experienced as
 larvae. To investigate whether this was occurring among Alaskan
 butterflies, we analyzed temporal trends in the wing sizes of three
 Holarctic species, Colias hecla, Boloria chariclea, and Boloria freija,
 using museum specimens collected in Arctic tundra regions of Alaska
 between 1971 and 1995. Wing length was compared to accumulated growing
 degree days (GDD) during both the spring of the year collected and the
 previous year’s summer during the normal period of larval development. We
 used mixed-effects models to test if spring and summer temperatures
 affected adult morphology. Results show that for every 1°C increase in
 average seasonal temperature, wingspans decreased between 0.7 millimeters
 and 5 millimeters, with B. freija the most strongly affected. Our results
 suggest that the morphological sensitivity of Arctic butterflies to
 warming is the outcome of interactions between life-history traits and
 regional climate, with all species sensitive to warming the summer before
 the flight year as well as warming the spring of the flight year. Boloria
 freija, which overwinters as late instar larvae that do not feed before
 pupation the following spring, was particularly strongly affected by
 summer warming.
description: # Wing lengths of three Arctic butterfly species decrease as summers warm
 in Alaska The data are
 provided in three ms excel spreadsheets. The first (wldoybarc.xlsx)
 describes the specimens and museum metadata, the second
 (weather_station_data.xlsx) the weather station / climate data, and the
 third (wlspeciesflights_dryad.xlsx) the wing lengths and calculated
 growing degree days. ### **File: wlspeciesflights\_dryad.xlsx** Wing
 length and growing degree day data. * **Year**: Collection year *
 **barcode**: University of Alaska Museum (UAM) accession bar code * **box
 barcode**: UAM barcode for the box containing the specimen * **box**: Box
 label * **envelope**: UAM barcode for the envelope containing the specimen
 * **Species determined by**: Authority who identified the species of the
 specimen * **species length measurer**: Person who measured the specimen
 forewing length** ** * **region**: Region: W: Western North Slope, E:
 Eastern North Slop, SP: Seward Peninsula * **sex**: specimen sex (M =
 male, F = female) * **Previous Summer Station**: Code for the weather
 station for the summer priory to specimen collection * **Spring weather
 stationary**: Code for the weather station for the spring of specimen
 collection * **extrap_station**: Nearest operational weather station. 
 However, it required temperature imputation based on station data
 historically collected closer to the specimen collection location *
 **extrap_gdd0**: Gdd data after extrapolation, T0 = 0 degrees C *
 **extrap_gdd5**: Gdd data after extrapolation, T0 = 5 degrees C *
 **light_doy_cutoff**: DOY cutoff for gdd accumulation, differing by
 species based on life history phenology (Days from January 1) *
 **prev_summer_gdd**: Final previous summer accumulated gdd used in models.
  T0 = 5.  Units = Growing Degree Days * **spring_gdd**: Final spring of
 collection year accumulated gdd used in models. T0 = 5.  Units = Growing
 Degree Days ### **File: wldoybarc.xlsx** Specimen metadata from the
 University of Alaska Museum * **scientific name**: Genus species name of
 the specimen * **location**: Physical description of collection
 location     * **mon**: Month of collection    * **day**: day of month of
 collection * **yr**: Year of collection * **doy**: Day of year (Number of
 Days after January 1):  Jan 1 = 0;  Dec 31 = 365 * **barcode**: University
 of Alaska Museum accession bar code ### **File:
 weather\_station\_data.xlsx** Temperature data * **STATION**: Station code
 * **NAME**: Station name   * **REGION**: Region: W: Western North Slope,
 E: Eastern North Slop, SP: Seward Peninsula * **LATITUDE**: Station
 latitude   (Degrees) * **LONGITUDE**: Station longitude  (Degrees)   *
 **ELEVATION**: Station elevation  (Meters) * **DATE**: Date of measurement
 * **MONTH**: Month of measurement * **DAY**: Day of month of measurement *
 **YEAR**: Year of measurement * **TMAX**: Maximum measured temperature
 that day (Degrees C) * **TMIN**: Minimum measured temperature that
 day  (Degrees C) **Note:**  Missing weather observations are denoted “NA”
 in the **weather_station_data.xlsx** datafile.