Wing lengths of three Arctic butterfly species decrease as summers warm in Alaska

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 t..., , , # 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
* ...