Circadian Rhythm in the Snail Helix Pomatia L. during Estivation and Hibernation

Abstract

Under natural conditions numerous life processes of animals show oscillations corresponding to nychthemeral fluctuations of environmental factors, such as light, ambient temperature (Ta), humidity (r.h.) etc.. Some of these diurnal biological cycles are directly caused by environmental changes — they disappear when the animals are kept under constant environmental conditions. In contrast to such exogenously driven biological cycles endogenous oscillations were found the cyclicity of which persists under constant environmental conditions with a period length of approximately 24 h (circadian rhythms).