Social signaling via bioluminescent blinks drives schooling behavior in the flashlight fishAnomalops katoptron

Abstract

19The bioluminescent flashlight fish Anomalops katoptron live in schools of several hundred specimens. 20To understand how flashlight fish, integrate bioluminescent signaling into their schooling behavior, 21 we analyzed movement profiles and blink frequencies. Isolated specimen of A. katoptron show a high 22 motivation to align with fixed or moving artificial light organs. Depending on presented frequencies 23 A. katoptron responds with a reduction in swimming speed and its own blink frequency. Higher 24 presented blink frequencies reduce the nearest neighbor distance. In the natural environment 25A. katoptron is changing its blink frequencies and nearest neighbor distance in a context specific 26 manner. Blink frequencies are increased from day to night and during avoidance behavior, while 27 nearest neighbor distance is decreased with increasing blink frequencies. A. katoptron changes its 28 blink frequencies by modifying light organ occlusion. Our results suggest that visually transmitted 29 information via specific blink patterns determine intraspecific communication and group cohesion in 30 schooling A. katoptron. 31 7 determined for 1 Hz and 2 Hz stimulation (1 Hz (0.115 ± 0.008 m/s), 2 Hz (0.119 ± 0.006 m/s), 132 RM ANOVA 0.5 Hz compared to: 1 Hz, p = 0.014; 2 Hz, p = 0.023; Fig. 1D). 133 134