Variability in motor rhythms while in continuous darkness in three Ice Cave individuals (A–C) and four Clarksville Cave individuals (D–G) tested in the laboratory. Black boxes indicate periods while in darkness.

 
 
  Part of: Espinasa L, Collins E, Finocchiaro A, Kopp J, Robinson J, Rutkowski J (2016) Incipient regressive evolution of the circadian rhythms of a cave amphipod. Subterranean Biology 20: 1-13. https://doi.org/10.3897/subtbiol.20.10010