Shell morphology, growth pattern and population dynamics of the land snail Xerolenta obvia (Menke, 1828) in two areas of different climatic conditions within a temperate climate region

Abstract

To determine the relative role of climatic variables (temperature and precipitation) on land snail Xerolenta obvia populations, field surveys were conducted in Poland at two sites (SW and NE) with striking differences in climatic regime during two growing seasons. In a temperate climate of Central Europe X. obvia is an annual species with the majority of snails hatching in autumn. They overwinter as juveniles, continue their growth in spring and summer, and reproduce in the following autumn. Due to the comparatively milder climate, the SW population is more plastic, some individuals can live and reproduce longer. The two variants of the growth model are presented. We found that the length of growing season and temperature were additional factors determining differences in snails' growth and population dynamics between the sites. The growth rate of X. obvia is negatively correlated with the initial size of their shells and varies among sites. These two geographically distant populations differ in terms of their shell size and morphology. The SW population is characterised by larger, dark banded shells compared to the NE one, which is dominated by snails with smaller, white shells. A pattern of decreasing body size in areas with shorter growing season may explain differences in the shell size of X. obvia. Larger shells in regions with warmer and drier environment perhaps constitute responses to selection by environmental factors.

Selected life history traits of Leptaxis simia (Gastropoda: Hygromiidae) established in the laboratory

“…Intraspe-LIFE HISTORY TRAITS OF LEPTAXIS SIMIA (GASTROPODA: HYGROMIIDAE) cific variation in growth rate may lengthen attaining maturity until the next reproductive season even within the same population or in populations from different geographic regions (e.g. Cowie 1984, Staikou & Lazaridou-Dimitriadou 1990, Avivi & Arad 1993, Kuźnik-Kowalska et al 2013b, Proćków & Kuźnik-Kowalska 2016, Marzec et al 2020. The remarkable uniformity of growth rate found in our L. simia reaching adulthood might not be reflected in natural populations.…”

Reproduction and growth of Xerolenta obvia (Menke, 1828) (Gastropoda: Eupulmonata: Geomitridae) in laboratory conditions

“…The SW. population reproduced mainly in autumn, but juveniles of the smallest recorded age class were present from April to August. Few adults could survive for more than one season (MarzEc et al 2020).…”

“…Xerolenta obvia reached maturity in the year following hatching, similarly to that observed in the French populations of Cernuella virgata (Da Costa, 1778) and Helicella itala (Linnaeus, 1758) -two species of size, shell structure and habitat requirements similar to those of X. obvia (Moquin-tandon 1855). There is, however, substantial variation in the life cycles, depending on the habitat type or climate (Kiss et al 2005, lazaridou & chatziioannou 2005, baKEr 2012, MarzEc et al 2020. C. virgata normally had a single generation annually with massive egg hatching in autumn and fast juvenile growth until the next spring in Australia (PoMEroy 1969).…”

“…lazaridou-diMitriadou 1981, staiKou & lazaridou-diMitriadou 1991, hänsEl et al 1999, Kiss et al 2005, baKEr 2012. The information on the biology of X. obvia includes field observations on climate-dependent variations in life histories in the Mediterranean and Central Europe (lazaridou-diMitriadou 1995, lazaridou & chatziioannou 2005, MarzEc et al 2020; there is also a study further east in Belarus (zEMoglyadchuK 2019). Some fragmentary data are also provided by FröMMing (1954) and birdsall et al 2019.…”

Integrated rearing system proposal for Cantareus aspersus in experimental orchards: Growth models

“…The effects of these factors on growth have been broadly studied and include genetic factors, 8 environmental conditions, 5,11 stocking density, effect of crowding on growth and circadian rhythm, 2,12,13 food consumption and metabolism, 1,10,14,15 habitat preferences 16 humus effects, 17,18 interspecific relations, 12 among others.…”