10.60507/FK2/GZO1ZZBeckers, NiklasNiklasBeckers0009-0000-5531-0127University of Bonn, Department of GeographyHein, NilsNilsHein0000-0002-5172-8531Helmholtz Centre for Environmental Research, LeipzigVanselow, Kim AndréKim AndréVanselow0000-0003-3299-6220University of Erlangen, Institute of GeographyLöffler, JörgJörgLöffler0000-0002-9320-6168University of Bonn, Department of Geographybonndata2026Earth and Environmental SciencesBeckers, NiklasNiklasBeckersUniversity of Bonn, Department of Geography2026-04-172026-04-27841247892text/plaintext/plain1.0CC BY 4.0We studied how the distribution of body sizes in A. alpina across Northern Europe relates to the environment. Our aim was to confirm the existence of these two distinct phenotypes of the species and identify environmental drivers to explain their distribution. Our hypothesis was that the differentiation of the species is driven by patterns of snowmelt. We tested this by using a machine learning approach to model body sizes against environmental variables of a dataset with 1x1 km spatial and daily average temporal resolution. The data provided here are the measurements of Amara alpina pronotum width with accompanying information on environemtal variables. Climate data are publicly available from www.senorge.no under the respective coordinates given for each specimen.