Fig. 7. Two independent timers can be differentially regulated at the L2 stage. Activation of nAChRs by DMPP slows developmental speed without affecting the timing of molting, hence resulting in a lethal heterochronic phenotype. The nuclear receptor DAF-12 bound to a hormonal ligand is necessary to implement the developmental effect of nAChR activation. Environmental cues that reduce the available amount of liganded-DAF-12 or that delay the L2/L3 molt protect the animals from DMPP-induced lethality (see the text for a full discussion).