Figure 1.

The life cycle of C. elegans. Under replete conditions (green arrows), the C. elegans hermaphrodite hatches from the egg, passes through four developmental stages (L1–L4), and becomes a fertile adult. Under harsh environmental conditions (red arrows), including low food availability, crowding and elevated temperature, the animals enter the dauer diapause instead of becoming L3 larvae. When environmental conditions improve, the dauers exit from the dauer state to become L4s and then fertile adults.