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Helix lutescens Rossmässler, 1837 is a xerothermophilous species. It reaches its NW distribution border in SE Poland. The studies, carried out in 1990–1997, involved the distribution of H. lutescens in Poland, its biology and ecology. Besides, shell structure and internal organs were studied, with special reference to differences between H. lutescens and the related H. pomatia L. In H. lutescens the shell is roundish-conical, of a yellowish- white colour and much smaller than that of H. pomatia. The body is greyish and covered with numerous wrinkles and grooves; fine, whitish granules are located in the grooves, especially in those that form two delicate light streaks along the darker back of the animal; these streaks are characteristic of the species. The reproductive system of H. lutescens is of a structure similar to that in H. pomatia, but the duct of the gametolythic gland never bears a diverticle while flagellum, epiphallus and penis in adults are pigmented. The diurnal activity of H. lutescens varies seasonally, depending on environmental factors (air temperature and relative humidity in ground layer, and substratum humidity – dew point). The reproductive activity reaches its peak in May and June. Courtship and copulation are in accordance with the typical helicid pattern. The copulation lasts ca. 15 mins, and the entire mating process takes over 3 hrs. Eggs are laid in nests dug in the soil, the mean number of eggs per nest being 35. In two weeks young hatch and remain in the nest for ca. 16 days. The abundance and density of three age classes in a selected population of H. lutescens have been estimated on a permanent sampling plot, using marking-release-recapture method, with JOLLY-SEBER‘S model for an open population. The results made it possible to trace seasonal changes in the abundance within the whole population. In Poland H. lutescens, because of its insular occurrence and the threat resulting from confusion with the edible H. pomatia, is a protected species.
Cepaea vindobonensis (Férussac, 1821) is recorded from two new localities in the Wielkopolska region, W Poland. The sites are located outside the continuous distribution range of the species, probably as remains of its more numerous insular localities in the Warta river valley.
Three types of columella structure have been distinguished in shells of selected snail species (Laciniaria plicata (Drap.), Chondrula tridens (O. F. Müll.), Cepaea vindobonensis (Fér.), Helix lutescens (Rossm.), Viviparus contectus (Millet), V. viviparus (L.), Helicella obvia (Menke) and Planorbarius corneus (L.)); they are correlated with the way of coiling, growth and convexity of whorls.
The paper presents results of two-year (2003–2005) monthly studies on terrestrial malacocoenoses in an ash-elm forest (Fraxino-Ulmetum) near Duszniki in western Wielkopolska (W. Poland). Species composition, dominance structure and abundance of malacocoenoses of selected plots were analysed. Twenty species of ten families were recorded, represented by 7,619 specimens. The main components of the malacocoenoses were Nesovitrea hammonis (Ström), Columella edentula (Drap.), Vallonia costata (O. F. Müll.), Punctum pygmaeum (Drap.), Cochlicopa lubricella (Porro) and Vertigo pusilla O. F. Müll. The species composition was stable but the abundance varied considerably.
Monacha cartusiana (O. F. Müller, 1774) was found at new sites in Poland: in Janikowo near Inowroc³aw and in Poznañ. At the site in Poznañ, adult individuals were relatively large, as their shell width ranged from 14.5 to 19.7 mm. It must be emphasised that adult individuals of M. cartusiana with shell width of nearly 20 mm have not been reported so far. The new sites of this snail indicate that it has become a permanent component of the Polish fauna.
The pneumostomes in Helix pomatia Linnaeus, 1758 and H. lutescens Rossmässler, 1837 are built in a similar way, but differ in the shape of the disc between the two pneumostome lobes, thus providing another diagnostically useful character.
The terrestrial gastropod fauna of the Drawa National Park includes 39 species, of which 29 (74.4%) were present in quantitative samples and subject to quantitative analysis. Dominant species were Aegopinella nitidula (Drap.), Discus rotundatus (O. F. Müll.) and Vitrea crystallina (O. F. Müll.). Snail communities of acid beech forest and a ruderal site with park tree stands in a mixed forest with beech had the highest species diversity index H’, while those of a eutrophic lowland beech forest and acid oak forest showed the highest TDI index of species diversity, and equitability index (J). The mean snail density was 19.3 indiv. m-2. The presence of Macrogastra ventricosa (Drap.), Laciniaria plicata (Drap.), Bulgarica cana (Held) and Helicigona lapicida (L.) is noteworthy.
Monacha cartusiana (O. F. Müller, 1774) was found in a new site in western Poland. The site is located in the city of Poznań, outside the continuous distribution range of the species. It is probably a result of accidental introduction by man.
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