On the significance of circadian clocks for insects

Abstract

Circadian clocks are ubiquitous and are believed to provide adaptive advantage to their owners in two different ways: (i) by synchronizing behavioral and physiological processes to periodic factors of the environment, and/or (ii) by coordinating various metabolic processes within the organism. The molecular mechanisms constituting circadian clocks are conserved across a wide range of taxa, and are relatively better understood for the fruit fly Drosophila melanogaster. There is growing evidence to show that the circadian architecture of Drosophila is multi-oscillatory and in some insects it shows developmental plasticity, i.e. differential response to light regimes experienced during pre-adult stages. It is argued that plasticity of circadian clocks is advantageous to insects living in fluctuating environments. Recent studies in social insects suggest that such plasticity in circadian systems may be crucial to the overwhelming success of social insects.