Cold hardiness abilities vary with the size of the land snail Cornu aspersum

Abstract

The land snail Cornu aspersum (syn. Helix aspersa) living in Brittany (France) can be considered partially freezing tolerant as it possesses a low ability to supercool and a limited capacity to bear freezing of its body tissues. The absence of a marked cold hardiness strategy permits the emphasis of the role of parameters such as individual size or water mass ( W M) contained by the organism. Adult snails (shell diameter 30–32 mm) had a supercooling ability, about 1–1.5 °C lower than that of immatures (shell diameter 12–20 mm) and survived longer to an exposure to −5 °C, with an Lt 50 comprised between 6.0 and 9.8 h against 2.6 to 4.2 h for immature snails. This better ability to bear freezing was explained by the faster dynamic of body ice formation observed in small individuals, which attained ice lethal quantity more rapidly. At the species level, large snails will then tend to be more tolerant to freezing and small ones to be freezing avoidant, a statement also observable at the phylum level.