Specialized behaviors accompany the molting cycle of C. elegans and provide a useful model to study the hormonal control of complex behaviors in higher metazoans. Behaviors of interest include the reversible quiescence that precedes ecdysis and distinctive actions used to break free of the old cuticle. We hope to learn how endocrine and possibly neuroendocrine signals regulate the behavior of C. elegans during the molting cycle and how particular behaviors are coordinated with renewal of the collagenous exoskeleton.

Lethargus

C. elegans cease locomotion and pharyngeal pumping for a brief period of time at the end of each larval stage. This period of quiescence is called lethargus and has been proposed as a model for sleep in humans. Larvae in lethargus move in response to provocation, consistent with neuronal regulation. Animals must resume activity in order to escape the old cuticle.

Escape tactics

C. elegans escape the old cuticle through a series of specialized movements that include drawing backwards, regurgitating some pharyngeal cuticle, and rotating on the long axis. Longitudinal rotation loosens old cuticle along the body. Larvae ultimately break free from the anterior end of their former skeleton with a forward thrust. The regulation of nematode behavior at ecdysis is not yet understood, but likely involves intercellular signaling as well as biological feedback.