Acetylcholine acts in part through levamisole receptors to regulate tail posture. (a) Ventral curling in wild-type versus unc-63(e384) males in 1 mM aldicarb. The highest amount of tail curling at the 25- and 30-minute time points (the time points where the most ventral tail curling was seen) for each trial was averaged. For all genotypes and conditions N = 20 *P < 0.05 Fisher's exact test. (b) Ventral and (c) dorsal male tail curling in levamisole (25 mM, N = 20; 10 mM, N = 21; 2.5 mM, N = 15; 1.0 mM, N = 21; 0.25 mM, N = 20; 0.1 mM, N = 19; ddH20, N = 30). Error bars indicate +/- standard error of the mean. W = water; A = aldicarb.