Fig. 2
From: Hydra vulgaris exhibits day-night variation in behavior and gene expression levels
Diurnal rhythm of spontaneous polyp contraction a Elongation (left) and contraction (right) of hydra polyps. The white bar indicates 1 mm. b, c Spontaneous polyp contraction under LD 12:12 cycles (n = 10). d, e Spontaneous polyp contraction under DD condition (n = 9). f, g Spontaneous polyp contraction under LL condition (n = 9). The data are shown as the mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001, one-way ANOVA, Tukey post-hoc test