Is cold hardiness size-constrained? A comparative approach in land snails

Armelle Ansart (1) , Annie Guiller (1) , Olivier Moine (2) , Marie-Claire Martin (1) , Luc Madec (1)

1 Stratégies évolutives et Dynamique spatiale des Populations
2 LGP - Laboratoire de géographie physique : Environnements Quaternaires et Actuels

Body water is a major element of the cold-hardiness strategies observed in ectothermic animals, in particular in freezing avoidant species for which body ice formation is lethal. Here, we investigate the relationships, in terrestrial snails, between the temperature of crystallisation (Tc) and body water (water mass and water content), shell shape, geographic and climatic distribution, taking into account phylogenetic inertia. Phylogenetic relationships among 31 species from 13 different families of terrestrial Gastropods were studied using 28S rRNA nuclear and COI mitochondrial sequence data, together with species-specific traits. Our results provide evidence for clear relationships between Tc and absolute / relative body water: smaller species with lower water content tended to be characterized by colder temperatures of crystallisation, although some exceptions were noticeable. Environmental conditions do not appear to affect Tc significantly, as well as shell shape which is however correlated with water content. This study confirmed that supercooling ability in land snails is size constrained, with consequences on cold-hardiness strategies.

Mots clés: PGLS; Phylogenetic relationships; Body water; Terrestrial gastropods; Temperature of crystallisation

Domaines: Evolution [q-bio.PE]

Armelle Ansart, Annie Guiller, Olivier Moine, Marie-Claire Martin, Luc Madec. Is cold hardiness size-constrained? A comparative approach in land snails. Evolutionary Ecology, 2013, 28 (3), pp.471-493. ⟨10.1007/s10682-013-9680-9⟩. ⟨hal-00909016⟩