Color Patches Research Articles

Spectral variation and pigmentary basis of ornamental and mimetic wing colour patches of swallowtail butterflies

Abstract Colours and colour patterns are diverse traits that are often used as visual signals. To test ecological and evolutionary drivers of these visual signals, a clear understanding of their nature and variation is necessary. Here we characterize variation in wing coloration of mormon swallowtail butterflies (Papilio, subgenus Menelaides). These species exhibit two kinds of colour patches on black wings: creamy white/yellow/green patches that are presumably used as sexual ornaments, and pure white patches that are presumably used as mimetic signals. Using reflectance spectrophotometry we quantified spectral properties of black wing background and colour patches between sexes, wing surfaces, and mimicry status. We found that brightness and saturation of the black background were less variable across sexes, wing surfaces, and mimetic/nonmimetic status. However, colour contrast and saturation were higher on dorsal surfaces than on ventral surfaces, and colour contrast between the black background and colour patches was higher in males than in females. Colour patches in nonmimetic butterflies were brighter and more saturated across the whole colour spectrum compared to mimetic butterflies. Thus, our study characterizes colour variation in an extraordinary signal radiation on the wings of swallowtail butterflies, a model clade in ecology, evolution, and genetics. Our results generate numerous hypotheses about the ecological and sexual functions of these colour patches, which may guide further behavioural experiments. Finally, using liquid chromatography-mass spectrometry we identified the pigment papiliochrome-II to be the chemical basis of the presumed sexual ornaments in mormon swallowtails.

Multimodal aspects of sentence comprehension: Do facial and color cues interact with processing negated and affirmative sentences?

Negation is usually considered as a linguistic operator reversing the truth value of a proposition. However, there are various ways to express negation in a multimodal manner. It still remains an unresolved issue whether nonverbal expressions of negation can influence linguistic negation comprehension. Based on extensive evidence demonstrating that language comprehenders are able to instantly integrate extralinguistic information such as a speaker's identity, we expected that nonverbal cues of negation and affirmation might similarly affect sentence comprehension. In three preregistered experiments, we examined how far nonverbal markers of negation and affirmation-specifically, the so-called "not face" (see Benitez-Quiroz et al., 2016) and red or green color (see Dudschig et al., 2023)-interact with comprehending negation and affirmation at the sentential level. Participants were presented with photos ("not face" vs. positive control; Experiments 1 and 2) or color patches (red vs. green; Experiment 3). They then read negated and affirmative sentences in a self-paced manner or judged the sensibility of negated and affirmative sentences (e.g., "No, I do not want to sing" vs. "Yes, I would like to buy a sofa"). Both frequentist statistics and Bayes factors resulting from linear mixed-effects analyses showed that processing times for negated and affirmative sentences were not significantly modulated by the nonverbal features under investigation. This indicates that their influence might not extend to sentential negation or affirmation comprehension. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Vomeronasal organ volume increases with body size and is dissociated with the loss of a visual signal in Sceloporus lizards.

Many organisms communicate using signals in different sensory modalities (multicomponent or multimodal). When one signal or component is lost over evolutionary time, it may be indicative of changes in other characteristics of the signalling system, including the sensory organs used to perceive and process signals. Sceloporus lizards predominantly use chemical and visual signals to communicate, yet some species have lost the ancestral ventral colour patch used in male-male agonistic interactions and exhibit increased chemosensory behaviour. Here, we asked whether evolutionary loss of this sexual signal is associated with larger vomeronasal organ (VNO) volumes (an organ that detects chemical scents) compared with species that have retained the colour patch. We measured VNO coronal section areas of 7-8 adult males from each of 11 Sceloporus species (4 that lost and 7 that retained the colour patch), estimated sensory and total epithelium volume, and compared volumes using phylogenetic analysis of covariance, controlling for body size. Contrary to expectations, we found that species retaining the ventral patch had similar relative VNO volumes as did species that had lost the ancestral patch, and that body size explains VNO epithelium volume. Visual signal loss may be sufficiently compensated for by increased chemosensory behaviour, and the allometric pattern may indicate sensory system trade-offs for large-bodied species.

Color morphs of the fire salamander are discriminated at night by conspecifics and predators

AbstractThe coexistence of multiple discrete color phenotypes (i.e. color polymorphism) has been studied in many diurnal species where environmental light allows most visual systems to chromatically discriminate color morphs. However, there is a large gap in our understanding of the discrimination thresholds and the function color polymorphisms play at night. We collected spectral data from the throats of red‐ and yellow‐morph males in a polymorphic population of the nocturnal amphibian Salamandra salamandra gallaica. We estimated the discriminability between morphs and their conspicuousness at night by fitting visual models of conspecifics and predators. We also collected morphological, behavioral and physiological data and assessed the abundance and activity patterns of each morph to explore their potential function. Visual models indicated that both conspecifics and predators can visually discriminate salamander color morphs under night‐light conditions. Assuming the potential role of yellow and red color patches as visual signals, putatively related to social signaling, we could suspect that these colors represent different adaptive optima. Red‐morph individuals had shorter bodies and lower body condition, but both morphs showed similar space use. In addition, both color morphs exhibited similar metabolic physiology, suggesting that the observed similarity in these traits may be better explained by the shared environmental conditions, rather than color. Finally, differences in the conspicuousness of red and yellow morphs could result in differential predation pressure.

Review of the Narrow-Banded Hawkmoth, Neogurelca montana (Rothschild & Jordan, 1915) (Lepidoptera: Sphingidae) in China, with Morphological and Phylogenetic Analysis.

Neogurelca montana (Rothschild & Jordan, 1915) is a species of the genus Neogurelca Hogenes & Treadaway, 1993, that was previously known from Sichuan, Yunnan, and Tibet, China. Recently, however, this species was also found in Beijing and Hebei. These populations differ from those in southwest China in body colour and the shape of the yellow patches of the hindwing-a paler body colour and triangular patches in the former and darker body colour and fan-like patches in the latter. Wing morphology, male and female genitalia, and molecular evidence (DNA barcodes) were analysed for the different localities of this species and three other Neogurelca species-N. hyas, N. himachala, and N. masuriensis. Our molecular data support the Beijing population of montana as a valid subspecies, which we describe as N. montana taihangensisssp. nov. Wing and genital morphology confirm the molecular conclusions. We also collected larvae of the new subspecies in the Beijing suburbs and describe its life history and larval hosts and compare them with those of N. himachala.

Odors modulate color appearance.

Our brain constantly combines multisensory information from our surrounding environment. Odors for instance are often perceived with visual cues; these sensations interact to form our own subjective experience. This integration process can have a profound impact on the resulting experience and can alter our subjective reality. Crossmodal correspondences are the consistent associations between stimulus features in different sensory modalities. These correspondences are presumed to be bidirectional in nature and have been shown to influence our perception in a variety of different sensory modalities. Vision is dominant in our multisensory perception and can influence how we perceive information in our other senses, including olfaction. We explored the effect that different odors have on human color perception by presenting olfactory stimuli while asking observers to adjust a color patch to be devoid of hue (neutral gray task). We found a shift in the perceived neutral gray point to be biased toward warmer colors. Four out of five of our odors also trend toward their expected crossmodal correspondences. For instance, when asking observers to perform the neutral gray task while presenting the smell of cherry, the perceptually achromatic stimulus was biased toward a red-brown. Using an achromatic adjustment task, we were able to demonstrate a small but systematic effect of the presence of odors on human color perception.

The great tit abdominal stripe contains a sexually dichromatic colour patch hidden from the human eye

Information on the exact nature of sexual dichromatism might be incomplete, often leading to the treatment of dichromatic species as monochromatic. This error is evident when the two sexes of a species look identical to the human eye, as in the great tit (Parus major). We measured reflectance in three sections (throat, breast, belly) of the abdominal black stripe of great tits during the pairing and nestling feeding periods and assessed differences between patch sections, sexes, and seasons using visual models. We found that the stripe, which had previously been considered a single, contiguous patch, consists of multiple patches. In males, the breast section differed markedly from the throat and belly sections in having higher total brightness and ultraviolet chroma, while the female’s breast seemed to be less bright than the two other regions, resulting in strong sexual dichromatism hidden from the human eye. Colouration was more pronounced in winter, but dichromatism was present in both periods. The hidden breast ultraviolet patch we discovered in males may act as a sexual ornament or a signal amplifier.

Transcriptomic analyses during development reveal mechanisms of integument structuring and color production

Skin coloration and patterning play a key role in animal survival and reproduction. As a result, color phenotypes have generated intense research interest. In aposematic species, color phenotypes can be important in avoiding predation and in mate choice. However, we still know little about the underlying genetic mechanisms of color production, particularly outside of a few model organisms. Here we seek to understand the genetic mechanisms underlying the production of different colors and how these undergo shifting expression patterns throughout development. To answer this, we examine gene expression of two different color patches(yellow and green) in a developmental time series from young tadpoles through adults in the poison frog Oophaga pumilio. We identified six genes that were differentially expressed between color patches in every developmental stage (casq1, hand2, myh8, prva, tbx3, and zic1). Of these, hand2, myh8, tbx3, and zic1 have either been identified or implicated as important in coloration in other taxa. Casq1 and prva buffer Ca2+ and are a Ca2+ transporter, respectively, and may play a role in preventing autotoxicity to pumiliotoxins, which inhibit Ca2+-ATPase activity. We identify further candidate genes (e.g., adh, aldh1a2, asip, lef1, mc1r, tyr, tyrp1, xdh), and identify a suite of hub genes that likely play a key role in integumental reorganization during development (e.g., collagen type I–IV genes, lysyl oxidases) which may also affect coloration via structural organization of chromatophores that contribute to color and pattern. Overall, we identify the putative role of a suite of candidate genes in the production of different color types in a polytypic, aposematic species.

Hidden black and yellow thigh color acts as an aposematic signal in the Eastern Gray Treefrog (Hyla versicolor)

AbstractRecognizing form and function of animal defenses is paramount to understanding the ecological and evolutionary forces behind predator and prey dynamics. Color patterns are strongly related to defensive strategies in animals. Some rely on camouflage to avoid detection, while others are brightly colored and conspicuously signal their noxiousness to potential predators. Still others combine cryptic dorsal coloration with colorful patches that are concealed in resting position but are facultatively unveiled by special behavior or simply during activity. Such hidden conspicuous color patches may be an intermediate stage in the evolution from camouflage to aposematism. Many species, especially treefrogs of the family Hylidae, are generally considered to be cryptic, yet show colorful patches on their flanks or thighs and have defensive skin secretions that may have unpalatable properties. We investigated whether the conspicuous black and yellow spotted pattern on the thighs of Eastern Gray Treefrogs (Hyla versicolor) serve as an aposematic signal. We conducted a palatability study to test whether Gray Treefrog skin secretions are unpalatable, and a clay model field study to test whether the conspicuous black and yellow thigh pattern is an aposematic warning coloration that reduces predation. Frog secretions were discriminated against during palatability assays, and clay models painted with a spotted black and yellow pattern suffered lower predation rates. Our findings support the hypothesis that hidden color patches act as aposematic signals in Gray Treefrogs and suggest that more species benefit from aposematic coloration than currently appreciated.

Sequential processing facilitates Hebb repetition learning in visuospatial domains.

Exposure to the same information improves auditory/verbal short-term memory performance, but such improvement is not always observed in visual short-term memory. In this study, we demonstrate that sequential processing makes visuospatial repetition learning efficient in a paradigm that employs a similar design previously used for an auditory/verbal domain. When we presented sets of color patches simultaneously in Experiments 1-4, recall accuracy did not increase with repetition; however, once color patches were presented sequentially in Experiment 5, accuracy did increase rapidly with repetition, even when participants engaged in articulatory suppression. Moreover, these learning dynamics matched those in Experiment 6, which used verbal materials. These findings suggest that (a) sequential focus on each item facilitates a repetition learning effect, indicating a temporal bottleneck is involved early in this process and (b) repetition learning is mechanistically similar across sensory modalities even though these modalities differently specialize in processing spatial or temporal information. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Poster Session: Comparison of brightness and vividness of colors with different background colors in PCCS.

The purpose of this study was to compare the brightness and vividness of color on different-colored backgrounds. The stimuli were 173 patches of colors lying within the Practical Color Co-ordinate System (PCCS). The backgrounds were three achromatic colors: white, mid-gray, and black. Each color patch was pasted on mounts colored each of the background colors, making 519 combinations. Participants evaluated the stimuli on scales of bright to dark (brightness) and vivid to dull (vividness) using the Visual Analog Scale app on an iPad. They viewed the stimuli in a D65 standard light source booth in a dark room. The brightness and vividness scores for the three background colors were compared using Bonferroni correction for multiple comparisons for each color. It was found that, for both brightness and vividness scores, there were considerably smaller differences between a white and a black background than between a black and a gray background or a white and a gray background. Color bias was shown, with significant differences arising compared to the PCCS tone. Brightness and vividness evaluations were correlated; thus, they were integrated using Principal Component Analysis. The loading of the first principal component was 0.826, and this new integrated dimension was termed "Brilliantness."

The idiosyncratic nature of how individuals perceive, represent, and remember their surroundings and its impact on learning-based generalization.

The current study adopted a multimodal assessment approach to map the idiosyncratic nature of how individuals perceive, represent, and remember their surroundings and to investigate its impact on learning-based generalization. During an online differential conditioning paradigm, participants (n = 105) learned the pairing between a blue color patch (CS +) and an outcome (i.e., shock symbol) and the unpairing between a green color patch and the same outcome. After the learning task, the generalization of outcome expectancies was assessed to 14 stimuli spanning the entire blue-green color spectrum. Hereafter, a stimulus identification task assessed the ability to correctly identify the CS + among this stimulus range. Continuous and binary color category membership judgments of the stimuli were assessed preconditioning. We found that a response model with color perception and identification performance as sole predictors was preferred to contemporary approaches that use stimulus as a predictor. Interestingly, incorporating interindividual differences in color perception, CS identification, and color categories significantly improved the models' ability to account for different generalization patterns. Our findings suggest that insight into the idiosyncratic nature of how individuals perceive, represent, and remember their surroundings provides exciting opportunities to understand post-learning behaviors better. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Measuring Perceptual Color Differences of Smartphone Photographs

Measuring perceptual color differences (CDs) is of great importance in modern smartphone photography. Despite the long history, most CD measures have been constrained by psychophysical data of homogeneous color patches or a limited number of simplistic natural photographic images. It is thus questionable whether existing CD measures generalize in the age of smartphone photography characterized by greater content complexities and learning-based image signal processors. In this paper, we put together so far the largest image dataset for perceptual CD assessment, in which the photographic images are 1) captured by six flagship smartphones, 2) altered by Photoshop®, 3) post-processed by built-in filters of the smartphones, and 4) reproduced with incorrect color profiles. We then conduct a large-scale psychophysical experiment to gather perceptual CDs of 30,000 image pairs in a carefully controlled laboratory environment. Based on the newly established dataset, we make one of the first attempts to construct an end-to-end learnable CD formula based on a lightweight neural network, as a generalization of several previous metrics. Extensive experiments demonstrate that the optimized formula outperforms 33 existing CD measures by a large margin, offers reasonable local CD maps without the use of dense supervision, generalizes well to homogeneous color patch data, and empirically behaves as a proper metric in the mathematical sense. Our dataset and code are publicly available at https://github.com/hellooks/CDNet.

A literacy-related color-specific deficit in rapid automatized naming: Evidence from neurotypical completely illiterate and literate adults.

There is a robust positive relationship between reading skills and the time to name aloud an array of letters, digits, objects, or colors as quickly as possible. A convincing and complete explanation for the direction and locus of this association remains, however, elusive. In this study, we investigated rapid automatized naming (RAN) of everyday objects and basic color patches in neurotypical illiterate and literate adults. Literacy acquisition and education enhanced RAN performance for both conceptual categories but this advantage was much larger for (abstract) colors than everyday objects. This result suggests that (a) literacy/education may be causal for serial rapid naming ability of non-alphanumeric items and (b) differences in the lexical quality of conceptual representations can underlie the reading-related differential RAN performance. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Female preference for males with lower pattern contrast follows Weber's law of proportional processing in jumping spiders

Abstract According to Weber's law of proportional processing, perceptual discrimination between stimuli of different magnitudes is based on their proportional differences in magnitude (not absolute differences). Proportional processing operates in various sensory modalities and behavioural contexts. However, whether female mate preference for colour patterns in animals follows Weber's law of proportional processing remains untested. We addressed this research gap using the jade jumping spider, Siler semiglaucus, whose males exhibit remarkable sexually selected colour patterns and whose females show preferences for males with low abdomen pattern contrast (pattern contrast is defined as the spatial feature of the relative abundance of two adjacent colour patches). By manipulating the dorsal abdomen colour patterns of S. semiglaucus males, we created males with varying abdomen pattern contrasts. We then assessed female preference for males that varied in both absolute and proportional differences in pattern contrast. We found that females preferred males with lower abdomen pattern contrasts and discriminated between males based on both absolute and proportional differences in pattern contrast. While proportional difference alone was not a significant predictor of female mate‐choice, discrimination based on proportional difference coupled with absolute difference had a greater influence on female mate preference than absolute difference alone. Hence, our findings suggest that S. semiglaucus female preference for males with lower pattern contrast follows Weber's law, and female discrimination may have the potential to limit the exaggeration of sexually selected colour patterns. Read the free Plain Language Summary for this article on the Journal blog.

The Role of the Organ in the Works of Zoltán Kodály

"Zoltán Kodály composed only two works for organ solo, the Organ Mass (Organoedia) and a Praeludium, which forms the introductory movement to the Pange lingua choral work. Nevertheless, his works involving the organ play a significant role in Hungarian organ music. The Hungarian idiom, characteristic for the composer's compositional style, is also reflected in the organ works, which form a very special, one might say exotic patch of color in the international organ repertoire. Keywords: organ, orchestra, choir, solo, accompaniment, text"

Assessment of coffee-ring effect on wool and cotton fabrics inkjet printed with herbal inks

In this study, the ecologically pre-treated wool and cotton fabrics were digitally printed with eco-friendly plant-based inks of blue, red, yellow, and black colours obtained from the plant extracts of bio indigo leaves, quebracho red bark and the flame of the forest flowers and evaluated for coffee-ring effect. The plant-based inks constituted from the Quebracho red bark and the flame of the forest flowers extract both demonstrated reduced dispersion diameter (i.e. diffused) for the Plasma Surface Treated (PST) wool and cotton fabric than the untreated. These findings could be applied for digital printing on photonics to combat the Coffee-ring effect. The possible explanation for the reduced coffee ring effect is the phenomenon known as Marangoni flow. The predominant phytochemicals functioning as chromophores namely indigotin, tannin and butein enclosed in inks constituted from the plant extracts of bio indigo leaves, quebracho red bark and the flame of the forest flowers respectively are highlighted. Additionally, the synthesis of plant-based ink, the colour scheme adapted for determining the inks colours, and the technique of print process as implemented in the study are explained. Likewise, the Colour patch, Percentage (%) Reflectance, and, Colour difference graphs as acquired from Datacolor tools are demonstrated. To end, the wash fastness, rub fastness, and light fastness test results obtained on wool and cotton fabrics digitally printed with innovative plant-based inks are detailed. The Life Cycle Analysis and assessment of functional phytochemicals on the resultant printed fabrics are suggested for future work.

Assessing patterns of eavesdropper risk on sexual signals and the use of meta-analysis in behavioural ecology: a comment on: ‘The exploitation of sexual signals by predators: a meta-analysis' White et al . (2022)

Assessing patterns of eavesdropper risk on sexual signals and the use of meta-analysis in behavioural ecology: a comment on: ‘The exploitation of sexual signals by predators: a meta-analysis' White <i>et al</i> . (2022)

Achromatic and chromatic contrast discrimination in patients with type 2 diabetes

Effects of type 2 diabetes on achromatic and chromatic contrast sensitivity (CS) are still controversial. In this study, we aimed to investigate CS in patients without diabetic retinopathy (no-DR) and in those with non-proliferative DR (NPDR) and proliferative DR (PDR) using psychophysical methods with transient and sustained achromatic stimuli and color patches. Achromatic CS was measured with the pulsed pedestal (PP) paradigm (7, 12, and 19 cd/m2) and pedestal-△-pedestal (P-△-P) paradigm (11.4, 18, and 28.5 cd/m2). A chromatic discrimination paradigm that assesses protan, deutan, and tritan color vision was adopted. Forty-two patients (no-DR n = 24, NPDR n = 12, PDR = 6; male n = 22, mean age = 58.1 y/o) and 38 controls (male n = 18, mean age = 53.4 y/o) participated. In patients, mean thresholds were higher than in controls and linear trends were significant in most conditions. For the PP paradigm, differences were significant in the PDR and NPDR groups in the 7 and 12 cd/m2 condition. For the P-△-P paradigm, differences were only significant in the PDR group in the 11 cd/m2 condition. Chromatic contrast loss was significant in the PDR group along the protan, deutan and tritan axes. The results suggest independent involvements of achromatic and chromatic CS in diabetic patients.

Method and analysis of color changes of facial skin after applying skin makeup

This study investigated facial skin color differences before and after makeup. Toward this goal, a photo gauge, devised with a pair of color checkers as a reference, collected face images. In addition, color calibration and a deep-learning method extracted the color values of representative areas of facial skin. The photo gauge photographed 516 Chinese females before and after applying makeup. Then, the collected images were calibrated by referencing skin color patches, and the lower cheek regions’ pixel colors were extracted using open-source computer vision libraries. Following the visible color spectrum of humans, the color values were computed in L*, a*, and b* of CIE1976L*a*b*. The results showed that the facial colors of the Chinese females changed to become brighter, less reddish, and less yellowish after applying the makeup, resulting in a paler skin tone. During the experiment, subjects were given five varieties of liquid foundation to choose one sample that best fits their skin. However, we failed to find any noticeable relationship between the individual’s facial skin color characteristics and the liquid foundation selected. In addition, 55 subjects were identified according to their makeup use frequency and skill, but their color changes did not differ from the other subjects. This study provided quantitative evidence of makeup trends in the Shanghai region in China, and the method proposes a novel approach toward remote skin color research.