Cuttlefish adopt disruptive camouflage under dynamic lighting

Many animals avoid detection or recognition using camouflage tailored to the visual features of their environment.1Merilaita S. Scott-Samuel N.E. Cuthill I.C. How camouflage works.Philos. Trans. R. Soc. Lond. B Biol. Sci. 2017; 37220160341https://doi.org/10.1098/rstb.2016.0341Crossref PubMed Scopus (148) Google Scholar,2Stevens M. Merilaita S. Animal camouflage: current issues and new perspectives.Philos. Trans. R. Soc. Lond. B Biol. Sci. 2009; 364: 423-427https://doi.org/10.1098/rstb.2008.0217Crossref PubMed Scopus (570) Google Scholar,3Cuthill I.C. Camouflage.J. Zool. 2019; 308: 75-92https://doi.org/10.1111/jzo.12682Crossref Scopus (106) Google Scholar The appearance of those features, however, can be affected by fluctuations in local lighting conditions, making them appear different over time.4Cuthill I.C. Matchette S.R. Scott-Samuel N.E. Camouflage in a dynamic world.Curr. Opin. Behav. Sci. 2019; 30: 109-115https://doi.org/10.1016/j.cobeha.2019.07.007Crossref Scopus (37) Google Scholar,5Hughes A. Liggins E. Stevens M. Imperfect camouflage: how to hide in a variable world?.Proc. Biol. Sci. 2019; 28620190646https://doi.org/10.1098/rspb.2019.0646Crossref Scopus (46) Google Scholar Despite dynamic lighting being common in many terrestrial and aquatic environments, it is unknown whether dynamic lighting influences the camouflage patterns that animals adopt. Here, we test whether a common form of underwater dynamic lighting, consisting of moving light bands that can create local fluctuations in the intensity of light ("water caustics"), affects the camouflage of cuttlefish (Sepia officinalis). Owing to specialized pigment cells (chromatophores) in the skin,6Reiter S. Hülsdunk P. Woo T. Lauterbach M.A. Eberle J.S. Akay L.A. Longo A. Meier-Credo J. Kretschmer F. Langer J.D. et al.Elucidating the control and development of skin patterning in cuttlefish.Nature. 2018; 562: 361-366https://doi.org/10.1038/s41586-018-0591-3Crossref PubMed Scopus (65) Google Scholar these cephalopod mollusks can dynamically adjust their body patterns in response to features of their visual scene.7Hanlon R.T. Cephalopod dynamic camouflage.Curr. Biol. 2007; 17: R400-R404https://doi.org/10.1016/j.cub.2007.03.034Abstract Full Text Full Text PDF PubMed Scopus (325) Google Scholar,8Hanlon R.T. Chiao C.C. Mäthger L.M. Barbosa A. Buresch K.C. Chubb C. Cephalopod dynamic camouflage: bridging the continuum between background matching and disruptive coloration.Philos. Trans. R. Soc. Lond. B Biol. Sci. 2009; 364: 429-437https://doi.org/10.1098/rstb.2008.0270Crossref PubMed Scopus (184) Google Scholar,9How M.J. Norman M.D. Finn J. Chung W.-S. Marshall N.J. Dynamic skin patterns in cephalopods.Front. Physiol. 2017; 8: 393https://doi.org/10.3389/fphys.2017.00393Crossref PubMed Scopus (36) Google Scholar Although cuttlefish resting on plain or patterned backgrounds usually expressed uniform or disruptive body patterns, respectively,10Chiao C.C. Hanlon R.T. Cuttlefish camouflage: visual perception of size, contrast and number of white squares on artificial checkerboard substrata initiates disruptive coloration.J. Exp. Biol. 2001; 204: 2119-2125https://doi.org/10.1242/jeb.204.12.2119Crossref PubMed Google Scholar,11Chiao C.-C. Chubb C. Hanlon R.T. Interactive effects of size, contrast, intensity and configuration of background objects in evoking disruptive camouflage in cuttlefish.Vision Res. 2007; 47: 2223-2235https://doi.org/10.1016/j.visres.2007.05.001Crossref PubMed Scopus (52) Google Scholar,12Barbosa A. Mäthger L.M. Buresch K.C. Kelly J. Chubb C. Chiao C.-C. Hanlon R.T. Cuttlefish camouflage: The effects of substrate contrast and size in evoking uniform, mottle or disruptive body patterns.Vision Res. 2008; 48: 1242-1253https://doi.org/10.1016/j.visres.2008.02.011Crossref PubMed Scopus (143) Google Scholar exposure to these backgrounds in dynamic lighting induced stronger disruptive patterns regardless of the background type. Dynamic lighting increased the maximum contrast levels within scenes, and these maximum contrast levels were associated with the degree of cuttlefish disruptive camouflage. This adoption of disruptive camouflage in dynamically lit scenes may be adaptive, reducing the likelihood of detection, or alternatively, it could represent a constraint on visual processing.