Figure 4. Homeostatic rebound in Cassiopea.

Each blue line corresponds to a single jellyfish. The black line indicates the mean activity of all jellyfish. Dark gray shading indicates night periods. Maroon shading indicates perturbation periods with 10 s water pulses every 20 min. Jellyfish were exposed to different perturbation lengths (6 or 12 hours) at different times (day or night). The normalized activity of all jellyfish tracked over multiple days is plotted. Maroon horizontal lines show the mean activity of pre-perturbation day (solid) and pre-perturbation night (dashed). (A) Perturbation of 30 jellyfish for the last 6 hours of the night. (B) Perturbation of 26 jellyfish for the first 6 hours of the day. (C) Mean day and night activity pre- and post-perturbation for experiments shown in A and B. (D) Perturbation of 16 jellyfish for an entire 12-hour night. (E) Perturbation of 16 jellyfish for an entire 12-hour day. (F) Mean day and night activity pre- and post-perturbation for experiments shown in D and E. Black-horizontal lines in A, B, D, and E indicate the windows of time used for calculating pre- and post-perturbation means shown in C and F for both the night (bottom lines) and day (top lines). For the 6-hour experiments we compared the first 4 hours of the post-perturbation day to the equivalent time pre-perturbation, and also compared the first 6 hours of post-perturbation night to the equivalent time pre-perturbation. For the 12-hour experiments we compared the full 12-hour days and nights pre- and post-perturbation. Two-way ANOVA followed by post-hoc comparisons between experimental groups using Bonferroni posttest (*P<5×10⁻²). Both day and night 6-hour perturbation experiments include data from four laboratory replicates. Both day and night 12-hour perturbation experiments include data from two laboratory replicates. See Figure S4, Movie S2.