Cuttlefish, Sepia officinalis, commonly use their visually-guided, rapid adaptive camouflage for multiple tactics to avoid detection or recognition by predators. Two common tactics are background matching and resembling an object (masquerade) in the immediate area. This laboratory study investigated whether cuttlefish preferentially camouflage themselves to resemble a three-dimensional (3D) object in the immediate visual field (via the mechanism of masquerade/deceptive resemblance) rather than the 2D benthic substrate surrounding them (via the mechanisms of background matching or disruptive coloration). Cuttlefish were presented with a combination of benthic substrates (natural rocks or artificial checkerboard and grey printouts) and 3D objects (natural rocks or cylinders with artificial checkerboards and grey printouts glued to the outside) with visual features known to elicit each of three camouflage body pattern types (Uniform, Mottle and Disruptive). Animals were tested for a preference to show a body pattern appropriate for the 3D object or the benthic substrate. Cuttlefish responded by masquerading as the 3D object, rather than resembling the benthic substrate, only when presented with a high-contrast object on a substrate of lower contrast. Contrast is, therefore, one important cue in the cuttlefish's preference to resemble 3D objects rather than the benthic substrate.

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The pelagic Sargassum community represents an excellent model system to advance our understanding of how a complex habitat can influence biotic interactions. This study examined the habitat architecture of pelagic Sargassum fluitans to determine its effects on habitat selection for one shrimp species (Leander tenuicornis) and two fish species (Stephanolepis hispidus and Histrio histrio). Specifically, we manipulated interthallus spacing and depth of Sargassum habitats independently (i.e., in separate experimental trials) to test whether spatial components of habitat architecture influence habitat selection by these animal inhabitants. Additionally, two differing habitats (Sargassum vs intermingled seagrass species, Thalassia testudinum and Syringodium filiforme) were tested to determine whether structural components of habitat architecture influenced habitat selection. Results showed no significant effect of habitat selections for interthallus spacing experiments for L. tenuicornis and S. hispidus. However, H. histrio selected habitats with medium interthallus spacing characteristics in two experiments. All three animals selected habitats with a greater depth aspect. Finally, L. tenuicornis and H. histrio selected habitats with greater structural complexity (i.e., Sargassum habitat). These results demonstrate that habitat architecture (i.e., spatial and structural components) of Sargassum influences habitat selection by the aforementioned fauna and further illustrate that this pelagic macroalga is an essential habitat for multiple species.