In
ocr-2 mutants under optimal growth conditions,
tph-1::gfp expression in the ADF neurons is not visible under a dissecting fluorescence microscope, but
tph-1::gfp in ADF can be clearly observed in
ocr-2 dauers. However,
ocr-2;
dyf-1 mutant can turn on
tph-1::gfp in ADF even under non-dauer conditions.