Shell Banding and Color Polymorphism of the Introduced Snail Cepaea nemoralis (Gastropoda, Helicidae) in Lviv, Western Ukraine

Th e shell coloration was studied in more than three thousand adults of the grove snail, Cepaea nemoralis (Linnaeus, 1758), from 15 colonies discovered in 2019–2020 in Lviv City and in the immediate vicinity of its south-ern administrative border (Zubra village). In most colonies, relatively light phenotypes prevailed: most oft en P00000, less oft en Y00000 or Y00300. In total, more than a third of the collected specimens had the phenotype P00000. Great variability of the phenotypic and genetic structure of this introduced species in the study area was demonstrated, which usually does not have a clear connection with the locations of colonies or with the shading of habitats. Th is may be due to both random factors (founder eff ect, gene drift in recently formed colonies), and the relative youth of the colonies. In the future, the obtained data can be used to monitor possible long-term changes in the phenotypic composition of the investigated colonies to assess the potential eff ect of selective factors on this composition, fi rst of all, climatic selection outside the natural range of C. nemoralis.