Fig. 6. Proposed model for the requirement of the Notch signalling pathway during dauer development. Based on our observations, glp-1 and lin-12 play distinct and opposing roles during dauer development. We have shown that lag-2 in the IL2 neurons is downstream of all three known pathways and that this expression is regulated by UNC-130, which is required to repress lag-2 in the IL2 neurons during reproductive growth. LAG-2 expression in IL2 neurons will then activate GLP-1 in the adjacent AWC to block premature recovery and hence promote dauer maintenance. Signals that sense replete growth conditions somehow activate LIN-12, which, in cooperation with the insulin-like receptor DAF-2, promotes recovery from dauer. At present it is not clear whether insulin-like signalling functions in parallel or downstream of the lin-12 Notch signalling pathway. See Discussion for details.