Eye-like Pattern Research Articles

The Enchanted Gaze: Modification of Butterfly Eyespots in Flemish Art

Abstract As shown by Palaeolithic cave paintings, animals were the first subjects that humans began to depict and recall in their imagination, not solely for their utilitarian function. Some animals, due to distinctive morphological features, appear to have captured our ancestors’ attention in a special way. This is the case of animals with eye-like patterns, which have been reproduced in multiple ways and contexts throughout human history. This paper examines how Flemish artists have depicted a particular example of eye-like patterns, the eyespots on the wings of Aglais io butterflies, to understand whether these artists attributed any particular relevance to the eyespots. Modifications were identified by comparing 51 images of A. io specimens with 50 depicted ones by means of geometric morphometric using 34 landmarks and 12 semi-landmarks. Generally, eyespots resulted to be located towards the interior of the wing, enabling us to discriminate 92% of depicted A. io from real images. This tendency is in line with the observer centre bias but, in this case, applied to the production of pictorial images rather than to their visual fruition, and which might be called ‘a shifting location bias’. Moreover, the eyespots’ size was depicted with accuracy and minimal variation among painters, while the outline of the wings appeared to be subject to considerable artistic freedom. Overall, these findings highlight the importance attributed by the artists to the eyespots, sustaining the hypothesis concerning the salience of this feature in attracting human attention.

Patterns in Dried Droplets to Detect Unfolded BSA.

The morphological analysis of patterns in dried droplets has allowed the generation of efficient techniques for the detection of molecules of medical interest. However, the effectiveness of this method to reveal the coexistence of macromolecules of the same species, but different conformational states, is still unknown. To address this problem, we present an experimental study on pattern formation in dried droplets of bovine serum albumin (BSA), in folded and unfolded conformational states, in saline solution (NaCl). Folded proteins produce a well-defined coffee ring and crystal patterns all over the dry droplet. Depending on the NaCl concentration, the crystals can be small, large, elongated, entangled, or dense. Optical microscopy reveals that the relative concentration of unfolded proteins determines the morphological characteristics of deposits. At a low relative concentration of unfolded proteins (above 2%), small amorphous aggregates emerge in the deposits, while at high concentrations (above 16%), the “eye-like pattern”, a large aggregate surrounded by a uniform coating, is produced. The radial intensity profile, the mean pixel intensity, and the entropy make it possible to characterize the patterns in dried droplets. We prove that it is possible to achieve 100% accuracy in identifying 4% of unfolded BSA contained in a protein solution.

Body size determines eyespot size and presence in coral reef fishes.

Numerous organisms display conspicuous eyespots. These eye‐like patterns have been shown to effectively reduce predation by either deflecting strikes away from nonvital organs or by intimidating potential predators. While investigated extensively in terrestrial systems, determining what factors shape eyespot form in colorful coral reef fishes remains less well known. Using a broadscale approach we ask: How does the size of the eyespot relate to the actual eye, and at what size during ontogeny are eyespots acquired or lost? We utilized publicly available images to generate a dataset of 167 eyespot‐bearing reef fish species. We measured multiple features relating to the size of the fish, its eye, and the size of its eyespot. In reef fishes, the area of the eyespot closely matches that of the real eye; however, the eyespots “pupil” is nearly four times larger than the real pupil. Eyespots appear at about 20 mm standard length. However, there is a marked decrease in the presence of eyespots in fishes above 48 mm standard length; a size which is tightly correlated with significant decreases in documented mortality rates. Above 75–85 mm, the cost of eyespots appears to outweigh their benefit. Our results identify a “size window” for eyespots in coral reef fishes, which suggests that eyespot use is strictly body size‐dependent within this group.

Adaptive constellations of protective marks: eyespots, eye stripes and diversion of attacks by fish

Coloration of animals often includes spectacular markings that supposedly decrease predation risk. Many vertebrates have eye stripes that have been suggested to conceal the noticeable shape of the eye from predators. Another salient mark in a wide range of taxa that sometimes co-occurs with an eye stripe is the eyespot. Some eyespots divert strikes of attacking predators, but whether the eyelike appearance is essential for the divertive effect is not known. Although numerous species of fish provide iconic examples of spectacular coloration, experimental studies on the protective function of coloration against fish predators are scarce. We investigated the divertive potential of prey marks, using artificial prey and three-spined sticklebacks, Gasterosteus aculeatus, as a model for predator perception and behaviour. A significant proportion of attacking fish directed their strike towards an eyespot, but when compared to a square-shaped mark, the bias was not significantly stronger. Importantly, a stripe running through the eyelike mark strongly influenced the attacking fish. When presented simultaneously, the fish directed their strikes towards an intact eyelike shape and away from an eyelike shape disrupted by a stripe. Our results demonstrate that marks of different shapes differ in their divertive potential, and this may contribute to the wide occurrence of eyespots in prey. Importantly, they also show that a stripe can effectively decrease the salience of an eyelike pattern, which provides the first experimental evidence for the adaptive benefit for eye stripes. Moreover, the joint effect of the eyespot and the disruptive eye stripe indicates that prey marks with different functions can form adaptive constellations to manipulate the attack behaviour of predators.

Neuronal responses to face-like and facial stimuli in the monkey superior colliculus

The superficial layers of the superior colliculus (sSC) appear to function as a subcortical visual pathway that bypasses the striate cortex for the rapid processing of coarse facial information. We investigated the responses of neurons in the monkey sSC during a delayed non-matching-to-sample (DNMS) task in which monkeys were required to discriminate among five categories of visual stimuli [photos of faces with different gaze directions, line drawings of faces, face-like patterns (three dark blobs on a bright oval), eye-like patterns, and simple geometric patterns]. Of the 605 sSC neurons recorded, 216 neurons responded to the visual stimuli. Among the stimuli, face-like patterns elicited responses with the shortest latencies. Low-pass filtering of the images did not influence the responses. However, scrambling of the images increased the responses in the late phase, and this was consistent with a feedback influence from upstream areas. A multidimensional scaling (MDS) analysis of the population data indicated that the sSC neurons could separately encode face-like patterns during the first 25-ms period after stimulus onset, and stimulus categorization developed in the next three 25-ms periods. The amount of stimulus information conveyed by the sSC neurons and the number of stimulus-differentiating neurons were consistently higher during the 2nd to 4th 25-ms periods than during the first 25-ms period. These results suggested that population activity of the sSC neurons preferentially filtered face-like patterns with short latencies to allow for the rapid processing of coarse facial information and developed categorization of the stimuli in later phases through feedback from upstream areas.

Fabrication of Colloidal Crystals on Different Patterned Silicon Substrates by Self-Assembly Method

Silica and polystyrene (PS) microspheres assembled on two quite different patterned silicon substrates, cross-like pillar pattern and eye-like pattern, respectively. The results indicated that the surface pattern imposes a predetermined lattice orientation in colloidal crystals (CCs). Other influent factors, such as microsphere size, the altitude of pattern and the concentration of colloidal suspension, may also play an important role on the self-assembly process.

Neuronal responses to face‐like stimuli in the monkey pulvinar

The pulvinar nuclei appear to function as the subcortical visual pathway that bypasses the striate cortex, rapidly processing coarse facial information. We investigated responses from monkey pulvinar neurons during a delayed non-matching-to-sample task, in which monkeys were required to discriminate five categories of visual stimuli [photos of faces with different gaze directions, line drawings of faces, face-like patterns (three dark blobs on a bright oval), eye-like patterns and simple geometric patterns]. Of 401 neurons recorded, 165 neurons responded differentially to the visual stimuli. These visual responses were suppressed by scrambling the images. Although these neurons exhibited a broad response latency distribution, face-like patterns elicited responses with the shortest latencies (approximately 50 ms). Multidimensional scaling analysis indicated that the pulvinar neurons could specifically encode face-like patterns during the first 50-ms period after stimulus onset and classify the stimuli into one of the five different categories during the next 50-ms period. The amount of stimulus information conveyed by the pulvinar neurons and the number of stimulus-differentiating neurons were consistently higher during the second 50-ms period than during the first 50-ms period. These results suggest that responsiveness to face-like patterns during the first 50-ms period might be attributed to ascending inputs from the superior colliculus or the retina, while responsiveness to the five different stimulus categories during the second 50-ms period might be mediated by descending inputs from cortical regions. These findings provide neurophysiological evidence for pulvinar involvement in social cognition and, specifically, rapid coarse facial information processing.

Effect of Northern Pygmy-Owl (Glaucidium Gnoma) Eyespots on Avian Mobbing

AbstractEyespots (color patterns resembling eyes) are present in many taxa and often have important ecological functions. In some taxa, potential functions of eyespots have not been extensively examined, as is the case with pygmy-owls (Glaucidium spp.), many of which bear a conspicuous eye-like pattern on their nape. Using wooden replicas of Northern Pygmy-Owls (G. gnoma), with and without eyespots, we tested one potential function: whether eyespots affect mobbing behaviors of small forest birds. We measured the orientation of mobbing behaviors (where birds perched and flew at the model) and intensity of mobbing bouts (duration of bouts and number of mobbing individuals). Eyespots affected the most proximal behavior, close passing (flights directly at the model, resulting in an approach within 0.5 m). When eyespots were present, mobbers shifted away from eyespots, providing the first empirical evidence for a link between eyespots and avian mobbing.

EFFECT OF NORTHERN PYGMY-OWL (GLAUCIDIUM GNOMA) EYESPOTS ON AVIAN MOBBING

Abstract Eyespots (color patterns resembling eyes) are present in many taxa and often have important ecological functions. In some taxa, potential functions of eyespots have not been extensively examined, as is the case with pygmy-owls (Glaucidium spp.), many of which bear a conspicuous eye-like pattern on their nape. Using wooden replicas of Northern Pygmy-Owls (G. gnoma), with and without eyespots, we tested one potential function: whether eyespots affect mobbing behaviors of small forest birds. We measured the orientation of mobbing behaviors (where birds perched and flew at the model) and intensity of mobbing bouts (duration of bouts and number of mobbing individuals). Eyespots affected the most proximal behavior, close passing (flights directly at the model, resulting in an approach within 0.5 m). When eyespots were present, mobbers shifted away from eyespots, providing the first empirical evidence for a link between eyespots and avian mobbing.

The effect of eye-like schema on shuttling activity of wild house mice (Mus musculus domesticus): Context-dependent threatening aspects of the eyespot patterns

The effects of footshock and various light-spot models on the shuttling activity of mice were examined in a passive avoidance situation. It was found that mild footshocks elicited initial exploration followed by an increased tendency to escape from the compartment in which the shocks were administered. An encounter with models, consisting of various numbers of small yellow lights, without footshock did not cause significant differences in shuttling activity. But if the models were paired with footshock, a tendency to explore during the first trial, high readiness to escape, and avoidance learning were found. These were characterized by a temporary increase in number of gate crossings, a decrease in the time spent in the shocked compartment, and a considerable increase in latency to enter the shocked compartment. The most effective model had two horizontally arranged yellow lights, which may share some characteristics with eye-like patterns.

Ultrasonographic differentiation of hepatocellular carcinoma from metastatic liver cancer.

Ultrasonographic features of tumor nodules in 64 patients with hepatocellular carcinoma and 87 with metastatic liver cancer were analyzed for differential diagnosis. Sonographic characteristics of hepatocellular carcinoma were the mosaic, posterior echo enhancement, and lateral shadow patterns, which were rarely observed in metastatic liver cancers. Small hepatocellular carcinomas, less than 3 cm in diameter, showed a hypoechoic pattern. Metastatic liver cancers originating from the gastrointestinal tract were frequently hyperechoic irrespective of their size and the bull's-eye-like pattern was specific for metastases from the lung. These results indicate that ultrasonography is useful for the differential diagnosis of hepatocellular carcinoma and metastatic liver cancer.

The Function of Eyespot Patterns in the Lepidoptera

1. Lepidoptera belonging to several different families bear eyespot patterns on their wings, often with a very strong resemblance to the vertebrate eye. These have been derived from different morphological structures in different groups, and their evolution is therefore convergent within the order. 2. A study of two individual hand-reared Yellow Buntings has shown that the pursuit of flying insect prey is fully released at the bird's first encounter with a flying butterfly, but that the orientation of the attack is modified by experience. 3. Eyespot patterns are associated with displays which exhibit them. In the case of a Nymphalid butterfly, Nymphalis io, an experiment has shown that the display releases escape responses from Yellow Buntings, and that the major part of this effect is due to the four ocelli on the upper surface of the fore- and hind wings. Experiments with other species of insects suggest that other factors contributing include the bright field of colour surrounding the eyespots, the rhythmic movements of the display, and the rustling noise which accompanies it. The bird's responses to this display waned rapidly in the majority of individuals, but some birds became conditioned to avoid the butterflies altogether. 4. Experiments with models showed that circular patterns presented suddenly to feeding birds (Chaffinches, Yellow Buntings and Great Tits) release escape responses more effectively than do non-circular patterns of the same area and perimeter. An increase in the perimeter of the models, achieved by the use of three concentric circles of the same area as the single circle, increased its releasing value. A flat, eye-like pattern which was so shaded and distorted as to appear three-dimensional was more effective than a similar flat pattern which was not shaded, and hence was more bright. Large models were more effective than similar small ones. Waning was again rapid. The differential responsiveness to circular and non-circular patterns is inborn in the case of Great Tits and Chaffinches. 5. An experiment with mealworms artifically ornamented with small eye-like spots at their extremities has shown that such markings, placed on a prey-object, tend to direct to themselves the attack of Yellow Buntings. The waning of the element of disturbed orientation in the responses is slow, and may not be significant. 6. The deflection and intimidation effects are discussed. The origin of the predator's responses to deflection marks is not known, but it is suggested that intimidating eyespots act by mimicking the eyes of the large avian predators preying on the small insectivorous passerines which are among their natural enemies. It has been shown that many small passerines possess inborn responses to their predators, and it is probable that these are parasitised by the eyespot patterns of insects. Eyespot patterns must be regarded as wholly distinct from pseudaposematic colouration. The effect of experience on small passerines, either of the predator-model or of an ocellated imitator, is most usually the reverse of that sustained by a predator encountering the model or mimic in a true case of Batesian or Mullerian mimicry, and the restrictions on the population size of a pseudaposematic insect relative to its model do not apply to insects utilising the inborn responses of their predators.