The Impact of Temperature on Activity Patterns of Two Vertiginid Micro-Molluscs (Mollusca: Gastropoda) in Conditions of High, Constant Humidity

Abstract: The goal of this study was to check the activity pattern of two hygrophilous land snails: Vertigo moulinsiana Dupuy, 1849 and Vertigo angustior (Jeffreys, 1830) at 11 °C and 21 °C, in conditions of high, constant humidity. The activity of snails was investigated for two weeks and checked two times a day: at 7AM and 7 PM. One-way ANOVA has shown statistically significant differences in the activity patterns of the studied snails. Both species were more active at 11 °C than 21 °C however, V. moulinsiana was more active than V. angustior in both temperatures. The higher activity of both species at 11 °C may be due to the fact that these vertiginids lose more water under hot conditions than under cold even at the same saturation deficits. On the other hand, higher activity of the climbing species — V. moulinsiana which in nature is exposed to the greater temperature fluctuations than the litter dwelling V. angustior, may cause a quicker response to changes of the temperature, and protect from overheating in the growing season. The present study shows that in the light of climate changes, associated with the rise of temperature, both of the studied species will probably reduce activity even in conditions of height humidity.