Blinking behaviour in A. katoptron under graded dim light conditions, in darkness and while feeding defrosted zooplankton in darkness.

(a) Blink frequency (blinks/min) in A. katoptron with luminous light organs (A1-A5) and non-luminous light organs (Anl1-Anl3). Luminous and non-luminous fish rotated the light organs with a comparable frequency under 3 decreasing dim light conditions. White bars (1–3) indicate blink frequencies under dim light (i3-i1) conditions. Light grey bars indicate blink frequencies at night. Dark grey bars indicate blink frequencies while feeding frozen zooplankton. (b) Summarized percentiles of blink frequencies in A. katoptron with luminous (solid grey lines: A1-A5, n = 5; blue line: average A1-A5) and non-luminous light organs (dark grey lines: Anl1-Anl3, n = 3; red line: average Anl1-Anl3) under the conditions dim light i1-i3, dark and feeding with frozen zooplankton in the dark. (c) Mean time intervals based on single open & closed times of light organs during dim light (dl i1-dl i3; white squares), darkness (d, light grey squares), and feeding in the dark (f, dark grey squares) conditions. (d) Total relative distribution of open & closed light organs during dim light (dl i1-dl i3), darkness and feeding in the dark experiments. Icons illustrate color coding in c-d. Black indicates closed light organs for both luminous and non-luminous light organs. Blue indicates luminous open light organs. Red indicates non-luminous open light organs. Error bars indicate ± SEM.