The increase in the turning rate is part of the physiologic response to hyperosmotic stresses. A, Wild-type animals cultivated under the standard NGM plates of 150 mOsm display a higher turning rate in a hyperosmotic solution of 400 mOsm (NGM_400 mOsm, n = 32) than in a 200 mOsm solution (NGM_200 mOsm, n = 28); but animals that are cultivated on the plates of 400 mOsm display a turning rate in the solution of 400 mOsm (adapted_400 mOsm, n = 32) that is similar to that in the solution of 200 mOsm (adapted_200 mOsm, n = 32). Significant interaction between cultivating conditions and osmolarity is tested by two-way ANOVA. B, The osr-1(rm1) mutant animals do not display an increased turning rate in the hyperosmotic solution of 400 mOsm (n = 29) compared with the turning rate in 150 mOsm (n = 28). Both the mutant and WT animals are cultivated under the standard osmotic condition of 150 mOsm. n = 29 and 31 for wild-type animals tested in solutions of 150 and 400 mOsm, respectively. C, The dpy-2(e8) mutant animals do not display an increased turning rate in the hyperosmotic solution of 400 mOsm (n = 16) compared with the turning rate in 150 mOsm (n = 16). Both the mutant and wild-type animals are cultivated under the standard osmotic condition of 150 mOsm. n = 16 for WT animals tested in each condition. For B and C, significant interaction between genotype and osmolarity is tested by two-way ANOVA. For all, ***p < 0.001. Values are reported as the mean ± SEM. WT, wild type.