Squid adjust their body color according to substrate

Abstract

Coleoid cephalopods camouflage on timescales of seconds to match their visual surroundings. To date, studies of cephalopod camouflage-to-substrate have been focused primarily on benthic cuttlefish and octopus, because they are readily found sitting on the substrate. In contrast to benthic cephalopods, oval squid (Sepioteuthis lessoniana species complex) are semi-pelagic animals that spend most of their time in the water column. In this study, we demonstrate that in captivity, S. lessoniana Sp.2 (Shiro-ika, white-squid) from the Okinawa archipelago, Japan, adapts the coloration of their skin using their chromatophores according to the background substrate. We show that if the animal moves between substrates of different reflectivity, the body patterning is changed to match. Chromatophore matching to substrate has not been reported in any loliginid cephalopod under laboratory conditions. Adaptation of the chromatophore system to the bottom substrate in the laboratory is a novel experimental finding that establishes oval squid as laboratory model animals for further research on camouflage.

The brain structure and the neural network features of the diurnal cuttlefish Sepia plangon

“…By contrast, the squid mainly relies on color changes on body surface to mimic the 2D background by manipulating colors to match with substrate while reaching close to floor and switching to countershading while hovering in water column. 3 , 18 , 97 Exactly how the cuttlefish nervous system dispatches signals via the additional 18 pathways identified here to govern skin patterns ( Figure 2 C) remains for future research. 11 , 13 , 18 , 98 , 99 …”

Comparative brain structure and the neural network features of cuttlefish and squid

“…By contrast, the squid mainly relies on colour changes on body surface to mimic the 2D background such as manipulating colours to match with substrate while reaching close to floor and switching to countershading while hovering in water column (e.g. S. lessoniana ) (Lu and Chung, 2017, How et al, 2017, Nakajima et al, 2022). Both chromatic and hydrostat systems are regularly used in the formation of cuttlefish body patterns (Gonzalez-Bellido et al, 2018, Alejandra et al, 2020, Osorio et al, 2022), and one additional set of neural components to coordinate those apparently more complex body patterns compared to a relatively simple system used for the squid chromatic-based patterns is revealed here (Figure 3).…”

Color-transparency dual-control devices based on patterned electrode-induced limited assembly of photonic liquid

“…As illustrated in Fig. 1a, chameleons use the arrangement of guanine nanocrystals inside their cell layers to achieve structural color changes, 1 while cephalopods regulate their transparency by controlling the scaling of their pigment cells 2 (Fig. 1b).…”