LONG-TERM DYNAMICS OF PHENETIC STRUCTURE IN COLONIES OF THE INTRODUCED SPECIES, CEPAEA HORTENSIS (GASTROPODA, PULMONATA, HELICIDAE)

摘要

In the periods from 1998 to 2004 and from 2015 to 2017, the quantitative distribution of phenotypes in 6 large urban colonies of Cepaea hortensis was investigated in the city of Lviv, western Ukraine. A significant temporal stability of such features of polymorphic structure as the percentage of molluscs with a banded and monochrome white shell and the distribution pattern of the phenotypes and types of band fusion among specimens with fused bands is shown. After a ten-year break in research at 4 sites out of 10, a statistically significant decrease in the percentage of specimens with a banded shell was recorded, which may be the result of climatic selection. At the same time, specific features of polymorphic structure at some sites were identified, which could be taken as the initial stages of genetic differentiation of C. hortensis colonies in urban conditions.