Thermal tolerance dataset for Greenlandic Arthropods

Raw data set for thermal tolerances of Greenlandic Arthropods. Each row represents an individual, with record of thermal tolerance, size and COI sequence used for taxonomic classification.Method of collection:Terrestrial arthropods (insects, arachnids and collembola) were collected in Narsarsuaq, Southern Greenland (61.160°N, 45.424°W). This region is characterized by cool temperatures, long winters and short summers (average -7 °C in January and +11˚C in July). The area has recently experienced rapidly increasing temperatures with mean annual temperature anomalies exceeding +1˚C on average (range -1.7 to +4.4˚C) since 2000 compared to the 1979-2023 baseline. Importantly, summers in the area are very thermally variable with maximum temperatures at ground level exceeding 30˚C⁵⁷. Ambient temperature was measured 7.5 cm above ground using TMS-4 loggers (TOMST) at 5 min resolution in two locations in Narsarsuaq (Figure S2). The study site is a heath-like, grass- and shrub covered area, where arthropods were collected from grasses and bushes using a sweep net or a pooter (a flexible tube used to catch animals directly from leaves or the ground). All individuals used in the experiment were caught in a 200 x 200 m area less than 100 m from the laboratory facilities. Animals were collected in the summer season from the 12^th of August until the 17^th of August 2023. All animals were collected during the day between 09:00 and 19:00, and all days throughout the study period showed similar temperature profiles. A subset of the collected arthropods was chosen based on morphological novelty (aiming at having as many different species as possible tested) and transferred to individual 5 mL glass vials with plastic screw-lids within 30 minutes after being collected. The vials with arthropods were kept outside of the laboratory in the shade for maximum one hour before being tested for either heat or cold tolerance. Animals were collected on six separate days constituting six batches. In each batch, between 80 and 138 individuals were tested. In total, 701 individuals were tested for either heat or cold stress tolerance.