Auteur / Autrice : | Annegret Nicolai |
Direction : | Maryvonne Charrier, Juliane 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
Mots clés contrôlés
Résumé
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.