Figure 3.

Lack of beads identifies dauer larvae formed in response to starvation or dauer pheromone. (A) Photomicrographs of larvae that have been washed from a starved plate onto a bead-containing plate and allowed to feed for 30 min. Nondauer larvae (top) contain beads in their digestive tracts, whereas dauer larvae (bottom) lack beads. These photos were taken on a compound microscope (63 × objective). (B–D) Averages of at least three independent trials ± SEM are shown. (B) Wild-type SDS-resistant dauer larvae from a starved population were placed on bead-containing plates and allowed to recover at 20° for the indicated times before observing them on a dissecting microscope. Min. PD = Minutes postdauer (n > 50). (C–D) Wild-type or mutant animals with abnormal cuticles were washed off starved plates and added to bead-containing plates. N2 = wild-type, CB1 = dpy-1(e1), VT1207 = lin-4(e912); mir-48 mir-241(nDf51); lin-14(n179) mir-84(n4037). After 30 min, they were scored on a compound microscope for dauer alae and radial constriction (n > 45) (C), or for resistance to 1% SDS (n > 40) (D). (E) Synchronized populations of wild-type larvae were grown at 24° on bead-containing plates supplemented by the addition of crude dauer pheromone. Larvae were monitored on a dissecting microscope before and during dauer formation. Data from multiple independent trials were aggregated and the total numbers are shown here. n = 25–83. (F) At 50 hr after egg laying (AEL), bead-lacking larvae from (E) were examined on a compound microscope for the indicated characteristics. Many larvae were still within the L2d-dauer molt, which was determined by the presence of indistinct dauer alae and an extra cuticle. The average ± SEM of at least three independent trials is shown. n = 68–155. L, larval stage; PD, postdauer; SDS, sodium dodecyl sulfate.