Differential regulation of developmental stages supports a linear model forC. eleganspostembryonic development

SUMMARY The repetitive nature of C. elegans postembryonic development is considered an oscillatory process, a concept that has gained traction from regulation by a circadian clock gene homolog. Nevertheless, each larval stage has a defined duration and entails specific events. We have measured the duration of each stage of development for over 2,500 larvae, under varied environmental conditions known to alter overall developmental rate. Our results show that distinct developmental stages respond differently to environmental perturbations, including changes in temperature, in food quantity and quality, and amount of insulin signaling. Furthermore, our high-resolution measurement of the effect of temperature on the stage-specific duration of development has unveiled novel features of temperature dependence in C. elegans postembryonic development. Altogether, our results support a model of linear progression of C. elegans development, with the duration of each stage determined by a unique program.