Effect of substratum drying on the survival and migrations of a freshwater pulmonate snail Planorbarius corneus (Linnaeus, 1758)

Abstract

Pulmonate snails inhabiting the near-shore zone of water bodies experience air exposure during water level fluctuations and some of them are known to survive long time in temporary basins. In laboratory, we investigated survival and behavioural defences (horizontal migrations and burrowing in substratum) of adult pulmonate snails Planorbarius corneus during substratum (sand and organic-rich) drying. We examined horizontal migrations at shorter and longer distances (24 and 48 cm), during gradual (8 days) or sudden water level drop rates. P. corneus was remarkably resistant to substratum drying, surviving 50 days on sand and more than 53 days on organic-rich bottom. The snails followed the retreating water level and grouped in the submerged parts of experimental tanks. This response was reduced on organic-rich bottom at a longer distance and with water level decreasing suddenly. Moreover, snails exposed to drying buried shallowly in both bottom types. Thus, P. corneus exhibited variable and efficient strategies enabling its survival during water level fluctuations, including active migrations following the retreating water level and burying in sediments.