scholarly journals Visual perception and camouflage response to 3-D backgrounds and cast shadows in the European cuttlefish Sepia officinalis

2021 ◽  
Author(s):  
Aliya El Nagar ◽  
Daniel Osorio ◽  
Sarah Zylinski ◽  
Steven M. Sait
Keyword(s):  
Retinal Image ◽  
The Body ◽  
Sepia Officinalis ◽  
Visual Depth ◽  
Depth Cues ◽  
Stage Process ◽  
Body Patterns ◽  
Camouflage Patterns ◽  
Large Repertoire ◽  
Body Pattern

To conceal themselves on the seafloor European cuttlefish Sepia officinalis express a large repertoire of body patterns. Scenes with 3-D relief are especially challenging because neither is it possible to directly recover visual depth from the 2-D retinal image, nor for the cuttlefish to alter its body shape to resemble nearby objects. Here we characterise cuttlefish's camouflage responses to 3-D relief, and to cast shadows, which are complementary depth cues. Animals were recorded in the presence of cylindrical objects of fixed (15mm) diameter, but varying in height, greyscale and strength of cast shadows, and to corresponding 2-D pictorial images. With the cylinders the cuttlefish expressed a ‘3-D’ 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 2-D backgrounds. This suggests that stationary cast shadows are not used as visual depth cues by cuttlefish, and that rather than directly matching the 2-D 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.

scholarly journals Perception of edges and visual texture in the camouflage of the common cuttlefish, Sepia officinalis

2008 ◽  
Vol 364 (1516) ◽  
pp. 439-448 ◽  
Author(s):  
S Zylinski ◽  
D Osorio ◽  
A.J Shohet
Keyword(s):  
The Body ◽  
Visual Environment ◽  
Sepia Officinalis ◽  
Visual Texture ◽  
Edge Information ◽  
The Common ◽  
Body Patterns ◽  
Mean Luminance ◽  
High Pass ◽  
Body Pattern

The cuttlefish, Sepia officinalis , provides a fascinating opportunity to investigate the mechanisms of camouflage as it rapidly changes its body patterns in response to the visual environment. We investigated how edge information determines camouflage responses through the use of spatially high-pass filtered ‘objects’ and of isolated edges. We then investigated how the body pattern responds to objects defined by texture (second-order information) compared with those defined by luminance. We found that (i) edge information alone is sufficient to elicit the body pattern known as Disruptive, which is the camouflage response given when a whole object is present, and furthermore, isolated edges cause the same response; and (ii) cuttlefish can distinguish and respond to objects of the same mean luminance as the background. These observations emphasize the importance of discrete objects (bounded by edges) in the cuttlefish's choice of camouflage, and more generally imply that figure–ground segregation by cuttlefish is similar to that in vertebrates, as might be predicted by their need to produce effective camouflage against vertebrate predators.

An ethogram of the Humboldt squid Dosidicus gigas Orbigny (1835) as observed from remotely operated vehicles

Behaviour ◽  
2015 ◽  
Vol 152 (14) ◽  
pp. 1911-1932 ◽  
Author(s):  
Lloyd A. Trueblood ◽  
Sarah Zylinski ◽  
Bruce H. Robison ◽  
Brad A. Seibel
Keyword(s):  
Open Ocean ◽  
The Body ◽  
Dosidicus Gigas ◽  
Remotely Operated Vehicles ◽  
Functional Roles ◽  
Video Recordings ◽  
Humboldt Squid ◽  
Body Patterns ◽  
Body Pattern

Many cephalopods can rapidly change their external appearance to produce multiple body patterns. Body patterns are composed of various components, which can include colouration, bioluminescence, skin texture, posture, and locomotion. Shallow water benthic cephalopods are renowned for their diverse and complex body pattern repertoires, which have been attributed to the complexity of their habitat. Comparatively little is known about the body pattern repertoires of open ocean cephalopods. Here we create an ethogram of body patterns for the pelagic squid, Dosidicus gigas. We used video recordings of squid made in situ via remotely operated vehicles (ROV) to identify body pattern components and to determine the occurrence and duration of these components. We identified 29 chromatic, 15 postural and 6 locomotory components for D. gigas, a repertoire rivalling nearshore cephalopods for diversity. We discuss the possible functional roles of the recorded body patterns in the behavioural ecology of this open ocean species.

scholarly journals A Report on Introduced Amazon Sailfin Catfish, Pterygoplichthys pardalis in Gombak Basin, Selangor, with Notes on Two Body Patterns of the Species

2020 ◽  
Vol 43 (4) ◽  
Author(s):  
Abdulwakil Olawale Saba ◽  
Nor Fariza Rasli ◽  
Ahmad Ismail ◽  
Syaizwan Zahmir Zulkifli ◽  
Intan Faraha A. Ghani ◽  
...  
Keyword(s):  
Fish Species ◽  
The Body ◽  
Introduced Fish ◽  
Aquatic Biodiversity ◽  
First Report ◽  
Body Patterns ◽  
Body Pattern

Invasive introduced fish species are well known for their deleterious impacts on aquatic biodiversity and environment. This study provides the first report on the occurrence of introduced Amazon sailfin catfish, Pterygoplichthys pardalis from the Gombak basin, Selangor, Malaysia, where the suckermouth catfish, Hypostomus plecostomus and vermiculated sailfin catfish, Pterygoplichthys disjunctivus had been previously reported. Besides, selected morphometric and meristic measurements between P. pardalis and P. disjunctivus from the Pusu River, Gombak basin were compared. Moreover, we also described two body patterns of the P. pardalis collected from the river. The body pattern which does not fit entirely with the known characteristics of P. pardalis or P. disjunctivus is suspected to be a result of hybridization between both species, but deeper study should be conducted to confirm this claim.

scholarly journals Cephalopod dynamic camouflage: bridging the continuum between background matching and disruptive coloration

2008 ◽  
Vol 364 (1516) ◽  
pp. 429-437 ◽  
Author(s):  
R.T Hanlon ◽  
C.-C Chiao ◽  
L.M Mäthger ◽  
A Barbosa ◽  
K.C Buresch ◽  
...  
Keyword(s):  
Visual Cues ◽  
The Body ◽  
Background Matching ◽  
Disruptive Coloration ◽  
Size Contrast ◽  
Body Patterns ◽  
Three Body ◽  
Web Archive ◽  
Body Pattern ◽  
The Continuum

Individual cuttlefish, octopus and squid have the versatile capability to use body patterns for background matching and disruptive coloration. We define—qualitatively and quantitatively—the chief characteristics of the three major body pattern types used for camouflage by cephalopods: uniform and mottle patterns for background matching, and disruptive patterns that primarily enhance disruptiveness but aid background matching as well. There is great variation within each of the three body pattern types, but by defining their chief characteristics we lay the groundwork to test camouflage concepts by correlating background statistics with those of the body pattern. We describe at least three ways in which background matching can be achieved in cephalopods. Disruptive patterns in cuttlefish possess all four of the basic components of ‘disruptiveness’, supporting Cott's hypotheses, and we provide field examples of disruptive coloration in which the body pattern contrast exceeds that of the immediate surrounds. Based upon laboratory testing as well as thousands of images of camouflaged cephalopods in the field (a sample is provided on a web archive), we note that size, contrast and edges of background objects are key visual cues that guide cephalopod camouflage patterning. Mottle and disruptive patterns are frequently mixed, suggesting that background matching and disruptive mechanisms are often used in the same pattern.

Cell number in relation to primary pattern formation in the embryo of Xenopus laevis

Development ◽  
1979 ◽  
Vol 53 (1) ◽  
pp. 269-289
Author(s):  
Jonathan Cooke
Keyword(s):  
Cell Cycle ◽  
Pattern Formation ◽  
Cell Cycle Control ◽  
Cell Number ◽  
The Body ◽  
Morphological Evidence ◽  
Tail Bud ◽  
Cell Cycle Time ◽  
Mesodermal Cell ◽  
Body Pattern

Morphological evidence is presented that definitive mesoderm formation in Xenopus is best understood as extending to the end of the neurula phase of development. A process of recruitment of cells from the deep neurectoderm layers into mesodermal position and behaviour, strictly comparable with that already agreed to occur around the internal blastoporal ‘lip’ during gastrula stages, can be shown to continue at the posterior end of the presumptive body pattern up to stage 20 (earliest tail bud). Spatial patterns of incidence of mitosis are described for the fifteen hours of development between the late gastrula and stage 20–22. These are related to the onset of new cell behaviours and overt cyto-differentiations characterizing the dorsal axial pattern,which occur in cranio-caudal and then medio-lateral spatial sequence as development proceeds. A relatively abrupt cessation of mitosis, among hitherto asynchronously cycling cells,precedes the other changes at each level in the presumptive axial pattern. The widespread incidence of cells still in DNA synthesis, anterior to the last mitoses in the posterior-to-anteriordevelopmental sequence of axial tissue, strongly suggests that cells of notochord and somites in their prolonged, non-cycling phase are G2-arrested, and thus tetraploid. This is discussed in relation to what is known of cell-cycle control in other situations. Best estimates for cell-cycle time in the still-dividing, posterior mesoderm of the neurula lie between 10 and 15 h. The supposition of continuing recruitment from neurectoderm can resolve an apparent discrepancy whereby total mesodermal cell number nevertheless contrives to double over a period of approximately 12 h during neurulation when most of the cells are leaving the cycle. Because of pre-existing evidence that cells maintain their relative positions (despite distortion)during the movements that form the mesodermal mantle, the patterns presented in this paper can be understood in two ways: as a temporal sequence of developmental events undergone by individual, posteriorly recruited cells as they achieve their final positions in the body pattern, or alternatively as a succession of wavefronts with respect to changes of cellstate, passing obliquely across the presumptive body pattern in antero-posterior direction. These concepts are discussed briefly in relation to recent ideas about pattern formation in growing systems.

The restrictive effect of early exposure to lithium upon body pattern in Xenopus development, studied by quantitative anatomy and immunofluorescence

Development ◽  
1988 ◽  
Vol 102 (1) ◽  
pp. 85-99 ◽  
Author(s):  
J. Cooke ◽  
E.J. Smith
Keyword(s):  
Prolonged Exposure ◽  
Anatomical Study ◽  
Cell Number ◽  
The Body ◽  
General Nature ◽  
Gene Products ◽  
Fate Map ◽  
Normal Pattern ◽  
Quantitative Anatomy ◽  
Body Pattern

We have carried out an anatomical study of Xenopus larval and gastrula stages resulting from treatment of synchronous early blastulae for brief periods with Li+. We confirm the proposal that such treatment causes a particular transformation, and partial elimination, of the normal body pattern. Coordinated restriction of pattern, without appreciable loss of cell number, is seen in all three germ layers. The distortion has been investigated by quantitative study of mesoderms at a standard stage, in relation to the normal fate map for mesoderm, and with the help of immunofluorescence on sections for somitic muscle and for blood. In the extreme syndrome, mesoderm arises from all around the blastula as usual, but is symmetrical and corresponds to that arising near the dorsal/anterior meridian of the normally specified egg or embryo with a large posterior subset of the normal pattern values thus missing. The effect is independent of any inhibition of archenteron formation or mesoderm migration (i.e. the cell mechanics of gastrulation) incurred by the treatment. It is also quite separate from a syndrome caused by more prolonged exposure to Li+ during gastrulation. A small, but distinctive, anterior pattern region is also not expressed and, anomalously in relation to their general nature, these forms differentiate considerable blood tissue. We consider the implications of some details of the pattern restriction for our understanding of interaction in the normal development and propose that the Li+ embryo is likely to be useful as a specific ‘differential screen’, in relation to the normal, during the search for those gene products that mediate initial regionalization of the body.

The myth of visual depth cues IV: Shape-from-shading

2021 ◽  
Author(s):  
Lydia Maniatis
Keyword(s):  
Visual Experience ◽  
Shape From Shading ◽  
Visual Depth ◽  
Depth Cues ◽  
Depth Cue ◽  
Physical Fact

The popular idea that “shading” is a shape and depth “cue” is the result of a failure to appreciate that neither shading as a physical fact nor shading as a perceptual fact can serve to explain the process leading to visual experience, because the description “shading” does not apply to the proximal stimulation, where this process begins. Both perceived shape and perceived illumination are products of figural constraints.

Effect of Stationary Objects on Illusory Forward Self-Motion Induced by a Looming Display

Perception ◽  
1988 ◽  
Vol 17 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Masao Ohmi ◽  
Ian P Howard
Keyword(s):  
Inhibitory Effect ◽  
The Body ◽  
Body Motion ◽  
Depth Cues ◽  
Circular Vection ◽  
Stationary Objects ◽  
Self Motion ◽  
Stationary Background

It has previously been shown that when a moving and a stationary display are superimposed, illusory self-rotation (circular vection) is induced only when the moving display appears as the background. Three experiments are reported on the extent to which illusory forward self-motion (forward vection) induced by a looming display is inhibited by a superimposed stationary display as a function of the size and location of the stationary display and of the depth between the stationary and looming displays. Results showed that forward vection was controlled by the display that was perceived as the background, and background stationary displays suppressed forward vection by about the same amount whatever their size and eccentricity. Also, the perception of foreground — background properties of competing displays determined which controlled forward vection, and this control was not tied to specific depth cues. The inhibitory effect of a stationary background on forward vection was, however, weaker than that found with circular vection. This difference makes sense because, for forward body motion, the image of a distant scene is virtually stationary whereas, when the body rotates, it is not.

Adaptive coloration in young cuttlefish ( Sepia officinalis L.): the morphology and development of body patterns and their relation to behaviour

1988 ◽  
Vol 320 (1200) ◽  
pp. 437-487 ◽  
Keyword(s):  
Motor Program ◽  
Predatory Fish ◽  
Adaptive Behaviour ◽  
Human Observer ◽  
Sepia Officinalis ◽  
Shadow Elimination ◽  
Use Patterns ◽  
Sexual Signalling ◽  
Body Patterns ◽  
The Moment

Young Sepia officinalis (0-5 months) were studied in the laboratory and in the sea, and their appearance and behaviour compared with that of adult animals. Cuttlefish lay large eggs and the hatchlings are miniature replicas of the adults. From the moment of hatching they show body patterns as complex as those of adults and far more elaborate than those shown by most juvenile cephalopods. There are 13 body patterns: 6 of these are ‘chronic’ (lasting for minutes or hours) and 7 are ‘acute’ (lasting for seconds or minutes). The patterns are built up from no fewer than 34 chromatic, 6 textural, 8 postural and 6 locomotor components, used in varying combinations and intensities of expression. Nearly all these components occur in young animals: 26 of the chromatic, all the textural and locomotor, and 6 of the postural components. Nevertheless, patterning does change with age and we have recorded this and correlated the changes with behaviour. The components are built up from units, which themselves comprise four elements organized in precise relation to one another: chromatophores, iridophores, leucophores and skin muscles. The chromatophores are always especially important: they are muscular organs innervated directly from the brain and controlled ultimately by the highest centres (optic lobes). The areas in the Sepia brain that control patterning are already well developed at hatching, for the appearance of the skin is as much part of the brain’s motor program as is the attitude of the arms or fins, or the posture of the entire animal. The iridophores and leucophores develop later and are especially important constituents of many adult patterns, notably the Intense Zebra of the mature male. Experiments confirm that patterning is neurally controlled and apparently mediated exclusively by the visual system. Young cuttlefish use patterning primarily for concealment, utilizing such strategies as general colour resemblance, disruptive coloration, obliterative shading, shadow elimination, disguise and adaptive behaviour. Older animals also conceal themselves but increasingly use patterns for signalling, both interspecifically (warning or ‘deimatic’ displays) and intraspecifically (sexual signalling). Laboratory-reared cuttlefish were released in the sea and observed underwater. They quickly and effectively concealed themselves on the substrate; it was easy for the human observer to lose them and many passing fish behaved as if they were not there. One local predator, Serranus cabrilla , was observed to attack them and no fewer than 35 attacks were recorded, only six of which were successful. Laboratory-reared cuttlefish apparently distinguished between these predators and other, non-predatory, fish the first time they encountered them in nature.

Physical activity behaviors related with construction of the body pattern for the prevention of mental disorders in spanish youth

2011 ◽  
Vol 26 (S2) ◽  
pp. 273-273
Author(s):  
A. Cocca ◽  
J. Viciana
Keyword(s):  
Physical Activity ◽  
Body Image ◽  
Mental Disorders ◽  
The Body ◽  
Educational Institutions ◽  
Physical Education Teachers ◽  
Sedentary Behaviors ◽  
Main Components ◽  
Age Range ◽  
Body Pattern

IntroductionA suitable body pattern is necessary for health. A wrong development of it could determine disorders in mental and physical areas (Ballesteros, 1982). To be active since childhood constitutes a primary factor for developing a good Body Mass Index (BMI) and body image, the main components of body pattern (Piéron, 2005).ObjectivesTo evaluate levels of physical activity (PA) and the relation with body pattern for the prevention of disorders in spanish youth.Methods3685 subjects aged 8 to 24 were selected from various educational institutions of Granada, Spain. Researchers took antropomethric measurements and submitted pupils to IPAQ questionnaire (Booth, 2000) and Body Image Assessment Scale (Thompson & Grey, 1995).ResultsResults showed that PA levels constantly decrease from Primary School until University (p = .001), and BMI increased at the same time. Body image kept constant values at each age range. We found significative correlations between PA and BMI and between BMI and body image (p = .001), but not between PA and body image.ConclusionsThis lack of correlation could mean that subjects have a wrong perception of their body, since they consider themselves healthy despite their BMI raise. This could explain the reduction of practice. This situation could determine the progressive onset of sedentary behaviors and mental disorders as anorexia or bulimia. In the future, Physical Education teachers should aim their classes at developing the perception of body through PA, to make pupils be active and to give them the basis for a suitable construction of body pattern.

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