1. Hypometabolism in land snails: Controlled or passive phenomenon?

Hypometabolism in land snails is an adaptive mechanism enabling survival in unfavourable environmental conditions such as the cold, frost, heat and drought. Both estivation and winter torpor are evoked by changes in ambient temperature, and humidity. Moreover, winter torpor is evoked by a decrease in photoperiod. But there is a growing body of evidence that maintenance in hypometabolic state and arousal from the torpor is under endogenous control, which prevents cell injury induced by extracellular freezing in winter and oxidative stress in both winter and summer. Hypometabolism in land snails is associated with molecular changes such as gene expression, selective inhibition of some protein synthesis, and changes in activities of same enzymes.