INTERNAL-POPULATION PROPERTIES OF HELIX ALBESCENS SHELLS IN THE NORTHWEST AZOV

Abstract

A comparative analysis of the clonic features of the Helix albescens terrestrial molluscs collected in the natural and anthropogenic biotopes of the northwest Azov in 2017-2018 is carried out. Samples were taken from 10 habitats of molluscs living within the borders of Melitopol and the region. In total 1325 specimens of shells of H. albescens were collected. The results of studying the interpopulation and intrapopulation variability of Helix albescens in shell height (SH), large diameter (LD), small diameter (SD), mouth height (MH), mouth width (MW). The area of the mouth (S), the conditional volume (V), the relative height of the mouth, the shape of the mouth and a number of indices were calculated. Trees and bushes vegetation was dominated on the most points of collecting material. The connection between morphometric features of mollusc shells and biotopic peculiarities of their habitation is revealed. The average variability of the shell size in the most of the samples is found, the value of Cv is between 10 and 20%. The lowest coefficient values of variation among the 14 samples were recorded for such parameter as height of the mouth. Comparison of shells Helix albescens sizes from territories with different anthropogenic loading showed that in the city the shells are bigger than in the countryside. The maximum sizes of shells had molluscs, which were collected within the area of Melitopol at points located in biotopes with multistory buildings, private sector and gardens, the smallest - at points located outside the city. Correlation analysis showed a high level of correlation dependencies for all shell parameters. The main morphometric molluscs’ shell indices have changed in wider ranges, which indicates a high variability. But in general, the relevant indicators are at the average level indicated for these species within the range.