Adaptive Functions of Circadian Rhythms
This extract was created in the absence of an abstract.
Excerpt
INTRODUCTION
It is not easy to evaluate the adaptive functions of rhythmic activities in animals for two reasons. First, because the interaction of the various physiological and ecological components is usually extremely complex; secondly, because the environmental factors to which rhythms are geared (“clues,” “synchronizers,” “Zeitgeber”) may bear little direct relation to the ecological factors most significant to the animal. For example, distribution of the webs of the Mediterranean spider Filistata insidiatrix (Forsk.) is determined by temperature, although the spiders stay in their heat-insulated tubes during the day. Now the prey of this species consists chiefly of woodlice, which are also nocturnal, and the spiders' webs are most numerous on the cooler and damper rocks where woodlice abound [1]. Again, the periodicity of the woodlouse Oniscus asellus (L.) depends upon the cycle of light and darkness, and is independent of temperature and humidity, although the latter factor is probably the...
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↵* Now of University of Khartoum, Sudan.
