El Nagar, A, Osorio, D, Zylinski, S et al. (1 more author) (2021) Visual perception and camouflage response to 3D backgrounds and cast shadows in the European cuttlefish, Sepia officinalis. Journal of Experimental Biology, 224 (11). jeb238717. ISSN 0022-0949
Abstract
To conceal themselves on the seafloor, European cuttlefish, Sepia officinalis, express a large repertoire of body patterns. Scenes with 3D relief are especially challenging because it is not possible either to directly recover visual depth from the 2D retinal image or for the cuttlefish to alter its body shape to resemble nearby objects. Here, we characterised cuttlefish camouflage responses to 3D relief, and to cast shadows, which are complementary depth cues. Animals were recorded in the presence of cylindrical objects of fixed (15 mm) diameter, but varying in height, greyscale and strength of cast shadows, and to corresponding 2D pictorial images. With the cylinders, the cuttlefish expressed a ‘3D’ body pattern, which is distinct from previously described Uniform, Mottle and Disruptive camouflage patterns. This pattern was insensitive to variation in object height, contrast and cast shadow, except when shadows were most pronounced, in which case the body patterns resembled those used on the 2D backgrounds. This suggests that stationary cast shadows are not used as visual depth cues by cuttlefish, and that rather than directly matching the 2D retinal image, the camouflage response is a two-stage process whereby the animal first classifies the physical environment and then selects an appropriate pattern. Each type of pattern is triggered by specific cues that may compete, allowing the animal to select the most suitable camouflage, so the camouflage response is categorical rather than continuously variable. These findings give unique insight into how an invertebrate senses its visual environment to generate the body pattern response.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2021. Published by The Company of Biologists Ltd. Reproduced in accordance with the publisher's self-archiving policy. |
Keywords: | 3D camouflage, 3D visual perception, 3D body pattern, Camouflage threshold, Two-stage response |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Biological Sciences (Leeds) > School of Biology (Leeds) |
Funding Information: | Funder Grant number BBSRC (Biotechnology & Biological Sciences Research Council) BB/L008815/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 17 May 2021 07:46 |
Last Modified: | 06 Mar 2023 19:53 |
Status: | Published |
Publisher: | The Company of Biologists |
Identification Number: | 10.1242/jeb.238717 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:174014 |