title: Influence of temperature acclimation and gut content on the supercooling ability of the land snail Cornu aspersum.
abstract: The invasive land snail Cornu aspersum possesses a low ability to supercool (c. -5 degrees C in winter) and survives only minimal ice formation in its body fluids, what may limit its expansion to colder environments. In the present study, we investigated the influence of acclimation and starvation on its supercooling ability. During eight weeks, individuals were maintained at 20 degrees C, fed or starved, or placed at 5 degrees C, directly or with progressive acclimation to cold and shorter photoperiod. Temperature of crystallisation of whole individual (Tc(I)) and hemolymph (Tc(H)), mass data and gut content were recorded every two weeks. Hemolymphatic glucose and glycerol were measured at the end of experiment and occurrence of intestinal ice-nucleating agents (INA) was researched. Acclimation had no effect on Tc(I) but stimulated purging of the gut. Starvation induced a slight decrease of Tc(I) whereas a high quantity of alimentary particles in the digestive tract limited the supercooling ability. Glucose and glycerol were not synthesized in cold conditions. Mean Tc(H) was low (c. -17 degrees C), some INA being present in hemolymph of fed animals. Intestinal content of starved individuals exhibited a mean Tc of c. -6 degrees C, decreasing to c. -12 degrees after heating, suggesting the presence of organic INA.
authors.affiliation: Université de Rennes 1, UMR 6553 Ecobio, SCA, bâtiment 14A, 263 Avenue du Général Leclerc, CS 74205, 35042 Rennes Cedex, France. armelle.ansart@univ-rennes1.fr
authors.forename: Armelle
authors.initials: A
authors.lastname: Ansart
authors.forename: Pierre-Aymeric
authors.initials: PA
authors.lastname: Aulne
authors.forename: Luc
authors.initials: L
authors.lastname: Madec
authors.forename: Philippe
authors.initials: P
authors.lastname: Vernon
mesh_terms: D000064:Acclimatization / Q000502:physiology*; D000375:Aging / Q000502:physiology; D000818:Animals; D001835:Body Weight; D003460:Crystallization; D041981:Gastrointestinal Tract / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D005990:Glycerol / Q000378:metabolism; D006458:Hemolymph; D012908:Snails / Q000502:physiology*; D013696:Temperature; D014867:Water / Q000378:metabolism
chemical_list: D014867:Water; D005947:Glucose; D005990:Glycerol