Figure 1. Both cave and surface balitorid species show pronounced locomotor rhythms.

Activity was measured as the number of movements per 30 min period (y-axis) and was plotted over the full period of observation. Individual actogram plots and LSP periodograms for surface (A, B), S. jaruthanini (C,D), S. spesei (E.,F), N. troglocataractus (G, H) and S. oedipus (I, J) over the full observation period show pronounced rhythmicity in all species. Period length as measured by the Lomb-Scargle algorithm (K) reveal a 24-hour circadian rhythm in all but one cave species. Period values in K represent peak period length (h)±1 LOD.