Thèse soutenue

L’effet du régime alimentaire sur la reproduction et les processus physiologiques chez les escargots terrestres Cornu aspersum et Helix pomatia
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Auteur / Autrice : Annegret Nicolai
Direction : Maryvonne CharrierJuliane Filser
Type : Thèse de doctorat
Discipline(s) : Biologie
Date : Soutenance en 2010
Etablissement(s) : Rennes 1 en cotutelle avec Universität Bremen
Ecole(s) doctorale(s) : École doctorale Vie-Agro-Santé (Rennes)
Partenaire(s) de recherche : autre partenaire : Université européenne de Bretagne (2007-2016)

Mots clés

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Résumé

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Organisms often encounter environmental heterogeneity in space and time, and may adapt their life histories. In Cornu aspersum reproductive strategy depended on seasonal time constraints, and the investment in reproduction was influenced by the energy available in the environment. Nutrients deposited in eggs might enhance offspring survival. In Helix pomatia that is used recently in low input snail farms in Germany to maintain this endangered species as a regional specialty under the name Albschneck®, showed low reproductive success even with high energy food. Helix pomatia preserves ice nucleating bacteria and accumulates cryprotectants to enhance cold hardiness during hibernation. Mortality could be related to perpetual physiological adjustments to high environmental variations but also be due to limited resource allocation to survival maintaining processes.