Juan A. Galarza (Ecology and Genetics Research Unit University of Oulu Oulu Finland) Juan A. Galarza Cristina Ottocento (Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences University of Helsinki Helsinki Finland) Cristina Ottocento Bibiana Rojas Bibiana Rojas Janne K. Valkonen (Department of Biological and Environmental Science University of Jyväskylä Jyväskylä Finland) Janne K. Valkonen Tamar Chunashvili (Invertebrate Research Center, Tetritsklebi Telavi Georgia) Tamar Chunashvili Tõnis Tasane (Fauna NPO Harju maakond Estonia) Tõnis Tasane Chris D. Jiggins (Department of Zoology University of Cambridge Cambridge United Kingdom) Chris D. Jiggins Johanna Mappes (Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences University of Helsinki Helsinki Finland) Johanna Mappes Ossi Nokelainen Ossi Nokelainen Melanie N. Brien Melanie N. Brien Wiley 2025 Online Version of Record before inclusion in an issue Coloration plays a pivotal role in shaping how species adapt to their environment, influencing their interactions with predators, prey, and potential mates. The aposematic wood tiger moth (Arctia plantaginis) is sexually dimorphic. Males are polymorphic in their hindwing coloration across the Holarctic distribution range, while females exhibit continuous variation in their coloration. In the Caucasus region, a striking exception can be found, where both sexes exhibit a continuous orange-red hindwing coloration. Yet, it remains uncertain whether significant color variations exist within the spectrum of male orange-red coloration and whether these differences can be associated with genetic structure or other phenotypic traits such as size. Using population genetics and image analyses methods, we find that males from the Lesser Caucasus have predominantly large red wings and constitute mostly a single genetic population. Males from the Greater Caucasus, in contrast, appear genetically isolated and are relatively small with orange hindwings. We discuss these findings in the context of both contemporary and historical environmental factors that may have influenced male color variation in the region. PDFDocument eng 2026-01-21T10:14:41.010199Z 2025 Arctiinae Color Polymorphism Genetic Structure Georgia Lepidoptera Multispectral Imaging 1190808 b application/pdf http://creativecommons.org/licenses/by/4.0/