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Common wall lizards (Podarcis muralis) in Italy show a striking variation in body coloration across the landscape, with highly exaggerated black and green colors in hot and dry climates and brown and white colors in cool and wet climates. Males are more intensely colored than females, and previous work has suggested that the maintenance of variation in coloration across the landscape reflects climatic effects on the strength of male–male competition, and through this sexual selection. However climatic effects on the intensity of male–male competition would need to be exceptionally strong to fully explain the geographic patterns of color variation. Thus, additional processes may contribute to the maintenance of color variation. Here we test the hypothesis that selection for green and black ornamentation in the context of male–male competition is opposed by selection against ornamentation because the genes involved in the regulation of coloration have pleiotropic effects on thermal physiology, such that ornamentation is selected against in cool climates. Field observations revealed no association between body coloration and microhabitat use or field active body temperatures. Consistent with these field data, lizards at the extreme ends of the phenotypic distribution for body coloration did not show any differences in critical minimum temperature, preferred body temperature, temperature‐dependent metabolic rate, or evaporative water loss when tested in the laboratory. Combined, these results provide no evidence that genes that underlie sexual ornamentation are selected against in cool climate because of pleiotropic effects on thermal biology. Research Highlights: Common wall lizards in Italy show a striking variation in coloration across the landscape with highly exaggerated coloration occurring in hot and dry climates.This could be because climate selects for coloration in warm climates and/or because the genes that underlie.We show that there are no differences in thermal traits between lizards with different color phenotypes providing limited evidence for the antagonistic pleiotropy hypothesis. [ABSTRACT FROM AUTHOR]

The mechanisms regulating plumage coloration appear to be phylogenetically conserved in avian species: the plesiomorphic character state is estrogen-dependent regulation, while testosterone, luteinizing hormone, and non-hormonal control are derived states. Limited data exist on the underlying regulatory processes of sexual dichromatism in the Eared Dove (Zenaida auriculata (Des Murs, 1847)). Since the Columbiformes order is close to basal branches, we hypothesized that estrogen and testosterone play a central role in the regulation of crown plumage coloration in the Eared Dove. To test this, we subjected adult males to a forced molt accompanied by an exogenous increase of estradiol and testosterone to determine whether the presence of these hormones during molting modified the spectrophotometric characteristics of the plumage. No significant differences were found between treatments and controls in the colorimetric variables hue, ultraviolet saturation, and brightness. Similarly, the avian visual model showed no perceptible changes in chromatic and achromatic signals in the individual male adults. We also analyzed the effects of estrogen and testosterone on the growth speed of the new feathers. The hormone-treated groups increased in the speed of molting compared to the control group. These results suggest that the Eared Dove is an exception to basal branch models: rather than regulating coloration, sex hormones speed up the growth of the new feathers. [ABSTRACT FROM AUTHOR]

Animal coloration serves a variety of visually related functions in nature (e.g. mate choice, aposematism and camouflage) but the pigments in integumentary tissues such as skin, scales and feathers may also serve functions unrelated to the visual environment (e.g. temperature regulation, detoxification and pollutant protection). Our understanding of the significance of the non‐visual functions of animal integumentary pigments, as well as how they interact with the visually related functions to shape animal visual systems, remains limited. Furthermore, due to their important roles in shaping species interactions and mediating interactions in the environment, animal colour traits are likely to be impacted by global change (e.g. increased temperatures, altered habitat quality and quantity, increased environmental stochasticity, pollutants and novel species assemblages). Considering the effects of global change on both visual and non‐visual functions is important for understanding whether the selection is acting directly on the pigment or on coloration. Since changing the trait distributions can then lead to changes in visual systems, we advocate for studies to consider all potential functions of integumentary pigments, both visual and non‐visual functions and their interaction. Towards this goal, we first highlight common functions of pigments with a focus on non‐visual functions across animal systems. Then we synthesize our current understanding of how global change can impact pigmentation and discuss factors that can modify the interactions between climate change and pigment function. Lastly, we discuss how changes in colour traits can impact visual systems and provide an example using amphibians and their responses to climate change as a model. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

To maximize camouflage across visually heterogeneous habitats, animals have evolved a variety of strategies, including polyphenism, color change, and behavioral background matching. Despite the expected importance of behavioral processes for mediating camouflage, such as selection for matching substrates, behavior has received less attention than color traits themselves, and interactions between color change and behavior are largely unexplored. Here, we investigated behavioral background matching in green and red chameleon prawns (Hippolyte varians) over the course of a color change experiment. Prawns were housed on mismatching green and red seaweeds for 30 days and periodically given a choice test between the same seaweeds in y-choice trials over the experiment. We found that, as prawns change color and improve camouflage (to the perspective of a fish predator), there is a reinforcing shift in behavior. That is, as prawns shift from red to green color, or vice versa, their seaweed color preference follows this. We provide key empirical evidence that plasticity of appearance (color) is accompanied by a plastic shift in behavior (color preference) that reinforces camouflage in a color changing species on its natural substrate. Overall, our research highlights how short-term plasticity of behavior and longer-term color change act in tandem to maintain crypsis over time. [ABSTRACT FROM AUTHOR]

In polygynous ungulates, males are often larger than females and bear more elaborate/larger weapons. Quantifying sexual dimorphism in different traits could provide insights into species-specific evolutionary pathways of sexual selection. Concerning the combination of secondary sexual traits, we found that Himalayan tahr (Hemitragus jemlahicus) is unique among the ~20 species in the tribe Caprini, as its body mass dimorphism is ~2-fold greater than the dimorphism in horn size, whereas horn shape appears to be near-monomorphic. Whilst horns show the same growth rate in both sexes, body mass increases faster in males. Considering age variation, dominant, golden-ruffed males are also heavier than brown-ruffed, lower-ranking males. Unlike most bovids, male–male competition in tahr does not seem to have influenced weapon development, suggesting a lower importance of horns in male–male competition compared to body mass, as their unritualized combat style also suggests. Our study highlights alternative evolutionary pathways occurring in the Caprinae, where intraspecific signals involve different traits, from weapons to pelage features. Accordingly, male tahr use their ruff colour as an 'honest' signal of rank. [ABSTRACT FROM AUTHOR]

In recent decades, studies on animal coloration have expanded significantly, from understanding color production and perception mechanisms to exploring the selective pressures driving these patterns. Conservation biology has begun leveraging these studies to develop effective strategies, gauge public support for conservation projects, select flagship species, and determine reproductive pairs and optimal rearing and release conditions for captive breeding. Critically endangered Aeolian wall lizards (Podarcis raffonei) were housed at the Fondazione Bioparco di Roma for a pilot captive breeding project following alarming hypotheses of rising numbers of "green" hybrids (P. raffonei × P. siculus) in one of the four surviving populations. Through a quantitative analysis of visible dorsal color in captive and natural populations, we aim to determine whether P. raffonei is characterized by seasonal variation in its dorsal coloration and if color is influenced by sex and ontogenesis. Our findings show that P. raffonei's dorsal pigmentation varies between seasons. In spring, the size and age of the animals does not seem to affect any color component, while the sexes always differ in their hue, with males having consistently more yellow-green dorsa. Between-year analyses, including measurements from the wild population, indicate that yearly variation is not limited to the captive population but also occurs in nature. We caution against identifying potential hybrids based solely on phenotypic traits. [ABSTRACT FROM AUTHOR]

The expression of sexually selected traits, such as ornaments or body coloration, is often influenced by environmental conditions. While such phenotypic plasticity is often thought to precede evolutionary change, plasticity itself can also be a target of selection. However, the selective forces supporting the evolution and persistence of plasticity in sexual traits are often unclear. Using the cichlid fish Astatotilapia burtoni, we show that variation in the level of mate competition may promote plasticity in body coloration. In this species, males can change between yellow and blue colour. We found that experimentally increased competition over mating territories led to a higher proportion of males expressing the yellow phenotype. The expression of yellow coloration was found to be beneficial because yellow males won more staged dyadic contests and exhibited a lower level of oxidative stress than blue males. However, females were more likely to spawn with blue males in mate choice experiments, suggesting that expression of blue coloration is sexually more attractive. The ability to adjust colour phenotype according to the local competitive environment could therefore promote the persistence of plasticity in coloration. [ABSTRACT FROM AUTHOR]

Masquerade is a form of camouflage in which animals use their body size, shape, and coloration to resemble inanimate objects in their environment to deceive predators. However, there is a lack of experimental evidence to show that animals actively choose objects that match these body parameters. To explore how the Hainan four‐eyed turtle, Sacalia insulensis, masquerades using suitable stones, we used indoor video surveillance technology to study the preferences of juvenile S. insulensis for stones of different sizes, shapes, and colors. The results indicated that under normal conditions, during the day, juvenile S. insulensis preferred larger oval or round stones, while at night, they preferred oval stones that were closer to their own size, with no significant preference for stone color during either time. When disturbed (by a researcher swinging their arm back and forth above the experimental setup every hour to mimic a predator), the turtles showed a preference for brown stones that were closer to their size and oval in shape. These findings suggest that juvenile S. insulensis prefer stones that resemble their carapace size and shape to masquerade when undisturbed, and that this preference is reinforced when they masquerade to reduce the risk of predation. The preference for stones that resemble their carapace color is significant only when there is a disturbance. To the best of our knowledge, this is the first study to provide evidence that vertebrates can selectively choose objects that resemble their own morphology for masquerading to reduce predation risk. [ABSTRACT FROM AUTHOR]

Coloration is crucial for ambush mesopredators' survival as they depend on it for camouflage to hunt and avoid predation. Furthermore, coloration is especially important in ectotherms as it is linked to two essential functions for survival: thermoregulation and crypsis. In a context of trade‐offs between thermoregulation and crypsis, the comprehension of how ectotherms employ color to address conflicting demands of thermoregulation and crypsis is limited. This study investigated background matching and thermoregulation in western diamond‐backed rattlesnakes (Crotalus atrox). Rattlesnakes were predicted to better match selected microhabitats in terms of color, luminance, and pattern than random microhabitats within their home range, and body temperature was predicted to influence their body coloration with higher temperatures favoring lighter colors. Pictures of 14 radiotracked western diamond‐backed rattlesnakes were taken in situ with a full spectrum camera (UV/VIS) and body temperature was recovered from internal temperature‐datalogging radiotransmitters. Crotalus atrox matched the color, luminance, and pattern of the background better than a randomly selected background, thus enhancing background matching. Additionally, rattlesnake coloration varied independently of temperature indicating that rattlesnakes are behaviorally modifying crypsis regardless of thermoregulation. [ABSTRACT FROM AUTHOR]

In most bird species, males are more ornamented and compete for females, who contribute more to offspring care. In a minority of species, this pattern is reversed, with more colorful females competing for mates and males taking care of parental duties. In such sex-role reversed species, the links between colorful ornamentation, individual quality and mating success are not well established. Phalaropus fulicarius (Red Phalarope) is a colorful sex-role reversed migratory shorebird with regular social polyandry, in which both sexes show considerable color variation. Here, we describe sex differences in color and quantify associations between color variation and indicators of quality and mating success in both sexes. Using a large sample of photos collected across 3 consecutive years on the Arctic breeding grounds, we scored color variation for 4 body parts (bill, crown, cheek, and breast), and analyzed scores separately and combined into an overall color score. Females were more colorful and larger than males, and individuals could be unambiguously sexed by crown color. Nevertheless, there was substantial variation within sexes and some overlap between males and females in bill, cheek, breast, and overall color scores. Assortative mating by color was only found for the bill. Color variation did not correlate with plasma testosterone levels, except for male cheek color. Females in better body condition had yellower bills and higher overall color scores, while early-arriving birds had higher breast and overall scores. Phalaropus fulicarius that bred locally were heavier than those that did not, but they did not have higher color scores. Female color variation did not predict the probability of local social polyandry nor variation in clutch size, and male coloration did not predict the probability of nest predation. In conclusion, P. fulicarius color variation showed modest correlations with individual quality and was unrelated to variation in local reproductive success. [ABSTRACT FROM AUTHOR]

Fish exhibit a broad spectrum of colors and patterns facilitated by specialized cells known as chromatophores. The vibrant coloration of fish, controlled by complex genetic and environmental interactions, serves critical roles in ecological functions such as mating, predation, and camouflage. This diversity not only makes fish an invaluable model for exploring the molecular mechanisms of pigmentation but also significantly impacts their economic value within the aquaculture industry, where color traits can drive marketability and breeding choices. This review delves into the sophisticated biological processes governing fish pigmentation and discusses their applications in enhancing aquaculture practices. By exploring the intersection of genetic regulation, environmental influences, and advanced breeding techniques, this review highlights both the scientific understanding and practical applications of fish coloration, providing a bridge between basic biological research and its application in commercial aquaculture. [ABSTRACT FROM AUTHOR]

Starch, a plant polysaccharide typically comprising amylose and amylopectin, exhibits a well-known property of turning blue upon encountering iodine. This color reaction, celebrated for its sensitivity, has found widespread application in experiments aimed at detecting iodine or starch. However, the coloration of starch upon iodine exposure is not always blue; rather, it varies depending on the starch composition. This study explores the diverse coloration exhibited by different food starches under various conditions (starch concentration, iodophor concentration, temperature, pH, polymerization degree), capturing the enchanting encounter between starch and iodine. Utilizing common food starches and iodophors as experimental materials, this educational experiment is costeffective, environmentally friendly, non-toxic, and user-friendly. By harnessing the distinct color reactions of starch and iodine, we create environmentally friendly multi-color ink, seamlessly integrating traditional calligraphy and Chinese painting techniques. Additionally, we explore captivating chemical experiments such as the magical iodine clock reaction, iodine fumigation for fingerprint analysis, and the preparation of non-Newtonian fluids from starch. With its strong appeal and broad audience reach, this experiment effectively employs gradient science popularization strategies. Through hands-on offline activities, participants experience the beauty of chemistry firsthand, fostering a deep appreciation and passion for the subject. The experiment yields significant outcomes in promoting scientific literacy and cultivating interest in chemistry among learners. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the use of EBT3 film, specifically the active layer, for monitoring low-energy ion beams. The film's wettability was enhanced, and its surface free energy increased by 200% after irradiation, as determined by the contact angle technique. SEM analysis showed that the surface of the film became rougher, with a needle-like structure, and increased from 80 nm for the pristine sample to 116 nm for the sample exposed to the highest fluence. XRD analysis revealed an increase in crystallite dimension and a decrease in crystallinity. ATR-FTIR analysis demonstrated that the modified film is sensitive to low-energy ion beams, with certain bands showing significant changes that can be controlled by adjusting the ion fluence. These changes affect the color properties of the EBT3 film, which can be used to monitor the ion beam. The visible spectrum exhibited two distinct colors: blue at 648 nm and red at 596 nm. The blue-to-red ratio was calibrated based on the applied fluence using a polynomial function. The film's net optical density was separately analyzed for each color, with the blue color being dominant. However, the red color accurately calibrated the film's response to low-energy ion beams with a usable fluence of up to 1 × 1017 ion/cm2. In conclusion, low-energy ion beams caused significant structural and optical changes in the active layer of EBT3 films, which can be controlled and customized for monitoring ion beams. [ABSTRACT FROM AUTHOR]

Fluorescence in amphibians and reptiles has emerged as a prominent study subject in recent years, with research focused on understanding its function and diversity. As the knowledge of fluorescence in vertebrates is still understudied, we surveyed amphibian and reptile species in montane and lowland Atlantic Forest sites to evaluate presence or absence of fluorescence. By randomly sampling species, we found evidence of fluorescence in amphibians of the genera Scinax, Brachycephalus and Hylodes, and reptiles of the genera Bothrops, Enyalius and Hemidactylus. Our findings increase the list of known species that may benefit from fluorescent patterns. Fluorescence was either ocular, dermal, or subdermal related to the skeleton or ossified dermal structures. Whether these species are able to see and interpret the different the patterns generated by fluorescent structures is yet to be discovered. [ABSTRACT FROM AUTHOR]

Astaxanthin is an important pigment for the rainbow trout Oncorhynchus mykiss. This study was conducted to investigate the effects of different sources of dietary astaxanthin on the growth, coloration, and antioxidant capacity of the commercial-sized O. mykiss during long-term feeding. Haematococcus pluvialis (HP), yeast Phaffia rhodozyma (PR), and synthetic astaxanthin (SA) were added to the basic feed (no astaxanthin, NA) to prepare the isonitrogenous and isolipidic experimental diets; the actual astaxanthin content values in the diets were 31.25, 32.96, and 31.50 mg/kg, respectively. Eighteen hundred O. mykiss, averaging 670 ± 20 g, were randomly divided into four groups and then fed with the experimental diet for four months. Dietary supplementation of P. rhodozyma and synthetic astaxanthin had no significant effects on the growth and tissue indexes of O. mykiss. In contrast, dietary supplementation with astaxanthin from H. pluvialis significantly increased the weight gain rate after four months of feeding. The fillet lightness of O. mykiss in the PR and SA was statistically lower than that in the NA and HP; the redness and astaxanthin content of fillet in the HP, PR, and SA groups were statistically higher than those in the NA. The total antioxidant capacity of the liver and serum in the HP was statistically higher than that in other diet groups, and a higher liver total superoxide dismutase activity was detected in the HP compared with the PR. Dietary supplementation of astaxanthin significantly increased the glutathione peroxidase activity in the liver and serum, and the highest serum glutathione peroxidase activity was detected in the HP, while dietary astaxanthin significantly decreased the malondialdehyde content in the liver and serum. Dietary supplementation of PR significantly increased the fillet ash content, while the highest fillet total lipid content was detected in the HP. Dietary astaxanthin significantly improved fillet redness and antioxidant capacity, among which H. pluvialis astaxanthin has greater effects on improving weight gain, antioxidant capacity, and fillet total lipid content. [ABSTRACT FROM AUTHOR]

The emergence of polychromic glazes during Tang period reflects intercultural communications than 1000 years ago. It also highlights a significant technological advance in ceramic history. However, the colouration mechanisms in high-fired Tang glazes are still not well understood. In this work, we unravel the mysteries of colourful Tang glazes through a case study of the Changsha kiln samples. Colorants in varied concentrations and oxidation states as well as microstructures resulted from phase separation and impurity are found responsible for the glaze appearances. More importantly, we highlight the mixing effects of different coloration ingredients that generate additional colours and hues. A direct observation of co-existence of reduced copper nanoparticles and liquid-liquid phase separation in Tang Changsha glaze is achieved as well. These fresh results and analyses provide an insightful assessment of the diversity of Tang Changsha glazes and promote the perception of ancient ceramics in a more scientific manner. [ABSTRACT FROM AUTHOR]

Many animals exhibit contrast between their dorsal coloration and their ventral coloration. If selection acts differently on dorsal versus ventral coloration, ancestral covariance between these traits should break down, eventually leading to independent modules of trait evolution. Here, we compare the evolution of feather color across body regions for a clade of Australasian songbirds (Meliphagoidea). We find evidence for three modules of covarying color regions. Among these modules, ventral feathers evolve with high lability, evolving at three times the rate of dorsal plumage and 20 times the rate of flight feathers. While both dorsal plumage and ventral plumage are darker in areas with more precipitation and vegetation, we find that dorsal plumage is twice as similar to colors in satellite photos of background substrates. Overall, differential selection on ventral and dorsal colors likely maintains these as distinct modules over evolutionary timescales—a novel explanation for dorsoventral contrast in pigmentation. [ABSTRACT FROM AUTHOR]

Caulerpa lentillifera, known as 'sea grapes´ or 'green caviar´, is increasingly in demand as a sea vegetable for human consumption. The seaweed is cultivated in ponds in the Khánh Hòa province in Van Phong Bay, Viet Nam, during the dry season (March-October). The harvested sea grape fronds are graded into different qualities based on their physical characteristics for retail on the local market or for export. Based on systematic observations of sea grape fronds of two different qualities, the frond weight, frond length and rachis coloration were identified as physical characteristics important for grading. Fronds of the best quality had significantly longer (12.59 ± 2.89 vs 10.01 ± 2.51 cm) and heavier (2.37 ± 0.59 vs 1.60 ± 0.5 g) fronds with darker rachis than the other quality group. However, a logistic regression model revealed that frond weight was the best predictor of frond quality. The physiological parameter of Fv/Fm was slightly different between the qualities, but always with means > 0.7, whereas the antioxidant activity and the total phenolic content were similar (98.34 ± 19.22 vs 95.96 ± 24.98 mmol TE (100 g)−1 DW and 163.8 ± 20.14 vs 149.85 ± 15.44 mg GAE (100 g)−1 DW). To the best of our knowledge, this study took a first approach to identify quality characteristics of sea grape fronds from Van Phong Bay, Viet Nam, which can serve as a basis for adjusting cultivation parameters to improve the harvest quality by developing cultivation and post-harvest protocols. However, further research is needed to investigate the effect of certain cultivation parameters on the specific frond characteristics. [ABSTRACT FROM AUTHOR]

Coloration in wildlife serves numerous biological purposes, including sexual selection signaling, thermoregulation, and camouflage. However, the physical appearance of wildlife also influences the ways in which humans interact with them. Wildlife conservation has largely revolved around humans' propensity to favor charismatic megafauna, but human perceptions of wildlife species extend beyond conservation measures into our everyday interactions with individual wildlife. Our aesthetic appreciation for different species interplays with culture, lore, and the economic interest they carry. As such, one characteristic that may underpin and interact with social drivers of perception is the coloration of a particular individual. We provide case studies illustrating the dynamism in interactions people have with conspicuously colored wildlife – i.e., individuals that vary from their species-typical coloration. We focus on melanism, leucism, and albinism across four species commonly thought of as pests in the United States: coyotes (Canis latrans), eastern gray squirrels (Sciurus carolinensis), white-tailed deer (Odocoileus virginianus), and black-tailed deer (O. hemionus). [ABSTRACT FROM AUTHOR]

Primates are remarkably colourful in comparison to other mammals. In particular, several species exhibit red–orange pelage or bright red skin, with the latter thought to signal status in intraspecific dominance interactions or to signal fertility. One potential driver of the interspecific diversity in red coloration is the primate visual system, which, uniquely among eutherian mammals, varies interspecifically and even between conspecifics in the ability to distinguish red and green (trichromatic colour vision). Previous comparative studies, however, have produced conflicting results regarding the proposed link between coloration and visual system. We employed an updated, sex-specific dataset of primate coloration and visual systems to re-examine the relationship between colour vision and red coloration across the entire order. With a few exceptions, increased colour visual ability is not significantly associated with the presence of red skin on the face or anogenital region, nor of red–orange pelage. We discuss possible reasons for the lack of colour–vision associations and suggest that dichromatic colour vision still facilitates effective signalling between conspecifics. [ABSTRACT FROM AUTHOR]

Positive frequency-dependent selection should theoretically lead to monomorphic warning coloration. Instead, numerous examples of polymorphic warning signals exist. Biases – for example, in human perception – hinder our appreciation and research of understanding warning signal diversity. We propose strategies to counter such biases and objectively move our field forward. Positive frequency-dependent selection should theoretically lead to monomorphic warning coloration. Instead, numerous examples of polymorphic warning signals exist. Biases – for example, in human perception – hinder our appreciation and research in understanding warning signal diversity. We propose strategies to counter such biases and objectively move our field forward. [ABSTRACT FROM AUTHOR]

The ability of individuals with visual impairment to recognize an obstacle by hearing is called "obstacle sense". This ability is facilitated while they are moving, though the exact reason remains unknown. This study aims to clarify which acoustical factors may contribute to obstacle sense, especially obstacle distance perception. First, we conducted a comparative experiment regarding obstacle distance localization by individuals who are blind (N = 5, five men with blindness aged 22–42 (average: 29.8)) while they were standing and walking. The results indicate that the localized distance was more accurate while walking than while standing. Subsequently, the head rotation angle while walking and acoustic characteristics with respect to obstacle distance and head rotation angle were investigated. The peaks of the absolute head rotation angle during walking ranged from 2.78° to 11.11° (average: 6.55°, S.D.: 2.05°). Regarding acoustic characteristics, acoustic coloration occurred, and spectral interaural differences and interaural intensity differences were observed in the blind participants (N = 4, four men including two blind and two control sighted persons aged 25–38 (average: 30.8)). To determine which acoustic factors contribute, we examined the threshold of changes for interaural differences in time (ITD) and intensity (IID) (N = 11, seven men and four women with blindness aged 21–35 (average: 27.4)), as well as coloration (ICD) (N = 6, seven men and a woman with blindness aged 21–38 (average: 29.9))—depending on the head rotation. Notably, ITD and IID thresholds were 86.2 μs and 1.28 dB; the corresponding head rotation angles were 23.5° and 9.17°, respectively. The angle of the ICD threshold was 6.30° on average. Consequently, IID might be a contributing factor and ICD can be utilized as the cue facilitating the obstacle distance perception while walking. [ABSTRACT FROM AUTHOR]

Simple Summary: Melanism, or the overexpression of melanin resulting in dark pigmentation, is fairly common among tree squirrels. The mutation that causes melanism has been discovered in two out of twelve species of tree squirrel that are known to have a melanistic phenotype. In this study, we identified the mutation that appears to cause melanism in a third species, Abert's Squirrel (Sciurus aberti). The mutation is a previously unknown mutation apparently unique to Abert's Squirrel, which suggests this mutation evolved independently from the other known mutations. Considering that three separate mutations are now known, it is likely there is a benefit for tree squirrels of having a dark, melanistic coat in certain environments. Melanism is widespread in different taxa and has been hypothesized to provide adaptive benefits in certain environments. Melanism is typically caused by mutations in one of two regulatory genes: the Melanocortin 1 Receptor (MC1R) or the Agouti Signaling Protein (ASIP). Melanism has repeatedly evolved among tree squirrels and their relatives (tribe Sciurini) in at least 12 different species based on our review of the literature. The causal mutations for melanism have been characterized in two species so far. This study examines Abert's Squirrel (Sciurus aberti), which has a melanistic morph whose genetic basis has not yet been established. We sequenced the MC1R and ASIP genes for five wild-type and seven melanistic S. aberti individuals to search for melanism-associated mutations. A novel single base pair mutation in the ASIP gene, unique to S. aberti, was found to be associated with melanism in the species, indicating that melanism in S. aberti evolved independently from other tree squirrels and thus represents an example of convergent evolution. The independent evolution of melanism in this species suggests that there is an adaptive advantage to the melanistic phenotype. The geographic range and habitat of S. aberti suggest possible benefits associated with thermoregulation, post-forest-fire camouflage, or other untested hypotheses. [ABSTRACT FROM AUTHOR]

The conventional method for the color-matching process involves the compounding of polymers with pigments and then preparing plaques by using injection molding before measuring the color by an offline spectrophotometer. If the color fails to meet the L*, a*, and b* standards, the color-matching process must be repeated. In this study, the aim is to develop a machine learning model that is capable of predicting offline color using data from inline color measurements, thereby significantly reducing the time that is required for the color-matching process. The inline color data were measured using an inline process spectrophotometer, while the offline color data were measured using a bench-top spectrophotometer. The results showed that the Bagging with Decision Tree Regression and Random Forest Regression can predict the offline color data with aggregated color differences (dE) of 10.87 and 10.75. Compared to other machine learning methods, Bagging with Decision Tree Regression and Random Forest Regression excel due to their robustness, ability to handle nonlinear relationships, and provision of insights into feature importance. This study offers valuable guidance for achieving Bagging with Decision Tree Regression and Random Forest Regression to correlate inline and offline color data, potentially reducing time and material waste in color matching. Furthermore, it facilitates timely corrections in the event of color discrepancies being observed via inline measurements. [ABSTRACT FROM AUTHOR]

The exotic pet trade has resulted in substantial invasion and disease risks, owing to the release of pets into new environments. Scientists have conjectured that pet owners acquire and release species with undesir- able traits because they are imperfectly informed about the traits of these animals. However, few studies have used social science methods to elicit pet owners' preferences for exotic pets. In 2019 we adminis- tered a best-worst choice survey to 1,055 exotic pet owners in the United States (who own pet reptiles, amphibians, fish, or invertebrates) to examine how human preferences and incomplete information may contribute to the risks of the exotic pet trade. Respondents preferred colorful and patterned species. On average, respondents preferred medium-sized amphibians and reptiles, small fish, and large invertebrates, although they demonstrated heterogeneity in preferences with respect to the adult size of pets. Respondents also preferred amphibians and reptiles with medium life expectancies and fish and invertebrates with long life expectancies, although they again demonstrated heterogeneity in preferences with respect to pets' life span. Respondents preferred docile animals, and were more likely to purchase lower-cost pets. We found some evidence that respondents' decision to purchase exotic pets depended on whether these animals were native, rare, had unusual morphological features, and breed easily. Respondents' decision to purchase specific taxa as exotic pets also depended on their age, education, and housing. Most respondents stated that they searched for information on pets' diet, behavior, adult size, life span, costs of care such as equipment or veterinary costs, and whether the animal was captive bred before purchasing these animals. Excepting pets' diets, fewer than half of respondents had been offered information on pets' traits by sellers. On average, respondents rated the information they had been offered as average. Respondents typically obtained additional information about pets from online searches. Our results suggest that certification systems that provide critical information on exotic pets' behaviors, adult size, longevity, fecundity, and husbandry needs should be implemented to prevent pet owners acquiring animals that they may subsequently abandon. [ABSTRACT FROM AUTHOR]

Traditional paper dyes are easy to fade under photothermal conditions, in contrast. waterborne organic pigments have excellent tinctorial strength and high light and weather resistance, which can meet the requirements of highend paper yarn to coloring efficacy and light fastness of the colorants. However, the lack of chemical and hydrogen bonds between organic pigment particles and plant fibers, and the pigments are difficult to fix in the structure of the paper. In this study, cellulose nanofibers (CNF/TOCNF) were used as the primary skeleton network and carboxymethyl cellulose (CMC) macromolecules were used as the secondorder reinforcement network, together construct a multilevel gradient network to enclose and fix organic pigment particles. The dispersion and fixation of the pigment particles are realized by double coating. The results show that the coloring efficacy and colorfastness of the paper yarn base paper can be improved significantly by using the gradient network to fix the pigment particles, and has a positive effect on improving the strength and roughness of the paper. This study has an important role in solving the problem of coloring technology in the production of high-end paper yarn. [ABSTRACT FROM AUTHOR]

There has been continuous interest in developing novel activators that facilitate the functionalization of cellulosic materials. In this paper, we developed a strategy in which trisubstituted triazinium salts act as cellulose preactivators. As leaving groups, these triazinium salts utilize N-heterocycles (pyridine, imidazole, and nicotinic acid). Initially, we optimized the synthetic route for developing these novel cellulose preactivators (triazinium salts), whose structures were confirmed using NMR spectroscopy. The surface zeta potential of cellulose changed from a negative value to a positive one after preactivation due to the cationic nature of these preactivators. To enhance the scope of the study, we functionalized the cellulose-preactivated materials with a series of amine- or hydroxy-containing aliphatic and aromatic hydrocarbons, nucleophilic amino acids (cysteine), colorants (2-aminoanthraquinone and 2-amino-3-methyl-anthraquinone), and biopolymer (zein protein). The treated samples were analyzed using FTIR, time-gated Raman spectroscopy, and reflection spectroscopy, and the success of the functionalization process was validated. To widen the scope of such chemistries, we synthesized four reactive agents containing N-heterocyclic-based leaving groups (pyridine and nicotinic acid) and successfully functionalized cellulose with them in one step. The proposed single- and two-step functionalization approaches will provide opportunities for chemically linking various chemical compounds to cellulose for different applications. [ABSTRACT FROM AUTHOR]

Plant multidrug and toxic compound extrusion (MATE) genes play an important role in the process of detoxification, plant morphogenesis, and anthocyanin accumulation. However, whether the MATE gene family functions in pear peel coloration is still unknown. To evaluate and identify the MATE gene family members which are involving in anthocyanin accumulation and coloration in pear. In this study, 85 MATE genes were identified in the reference pear genome of 'Dangshansuli' through genome-wide identification. Based on gene structure and phylogenetic tree analysis, the MATE family was divided into five subfamilies. RNA sequencing and quantitative real-time polymerase chain reaction (qRTPCR) indicated that the expression patterns of PbrMATEs were tissue-specific. 28.24% (24) of PbrMATE genes were expressed in the fruits, and 44.71% (38) of PbrMATE genes were expressed in the leaves. Additionally, we found that the expression levels of PbrMATE9, PbrMATE26, PbrMATE50, and PbrMATE69 in debagged fruits with red peel were significantly higher than those in bagged fruits without red peel, according to our bagging/debagging treatment of 'Mantianhong'. The expression pattern of PbrMATE9 was consistent with the variation trend in anthocyanin content, suggesting that it might play an important role in anthocyanin accumulation in response to light exposure. Subcellular localization showed that PbrMATE9 was a membrane protein. More strikingly, the transient overexpression of PbrMATE9 promoted anthocyanin accumulation in the peel of pear, and the expression of structural genes (PbrCHI, PbrANS, PbrDFR, and PbrUFGT) in the anthocyanin biosynthesis pathway also increased significantly. Through co-expression network analysis, the transcription factors were identified, such as WRKY, COL, GATA, and BBX, which might be involved in the regulation of PbrMATE9. The study has enriched the genetic resources and improved the understanding of the regulation network of anthocyanin accumulation in pear. [ABSTRACT FROM AUTHOR]

Carotenoids are diet-based micronutrients important in health and coloration signaling. Related species with similar diets can differ in the kinds and levels of circulating carotenoids, which suggests specific physiological mechanisms to efficiently utilize these micronutrients, regardless of their availability. We explored whether diet and parental provisioning of unusual sources of carotenoids (fresh vegetal matter and vertebrate feces) can explain the occurrence and concentrations of carotenoids in the cinereous vulture Aegypius monachus , griffon vulture Gyps fulvus , and Egyptian vulture Neophron percnopterus nestlings, even when these pigments appear to not be deposited in their integumentary system. A greater diversity of wild prey in diet could be behind the profile of higher concentrations of carotenoids in the Egyptian vulture, the species with carotenoid-dependent coloration during adulthood, while differences in diet composition between cinereous and griffon vultures do not translate to different carotenoid profiles. The carotenoid profile appears to not be related to the ingestion of unusual matter rich in these compounds, although the infrequent occurrence of lycopene and unidentified γ-carotene-like compounds suggest that these vultures may be exploiting vegetal matter that left no identifiable unconsumed remains in the nest of Egyptian vultures. The consumption of green plant material by griffon vultures does not result in especially high levels of carotenoids when compared to the carotenoids found in cinereous vultures, which do not consume green plant material. Ungulate feces were not provisioned to Egyptian vulture nestlings, despite the fact they contain carotenoids that adults need for appropriate coloration. Overall, this study indicates that diet differences alone appear insufficient to explain contrasting interspecific carotenoid profiles, especially since all types of food consumed are considered to be poor in carotenoids, except vegetable matter. We suggest that nestling Egyptian vultures are comparatively efficient in uptaking carotenoids present in low concentrations in food when these compounds are not deposited in their integument, which suggests allocation to other functions. [ABSTRACT FROM AUTHOR]

Knowledge of Didelphidae taxonomy and diversity has increased steadily over the last decades, mainly due to increasing collection efforts and revisionary works. Yet, especially for mouse opossums, a proper appraisal of morphological variation is still incipient. Thylamys karimii occurs in the Brazilian biomes of Caatinga and Cerrado, and specimens with two different shades of dorsal coloration (brown and gray) were recently documented in sympatry in the Parque Nacional (PARNA) do Catimbau (Caatinga biome). We used qualitative and morphometric data from skulls and skins (n = 7 from PARNA Catimbau and n = 26 from other localities) to compare these two coat color morphotypes and characterize the morphological diversity and taxonomic status of the Caatinga populations. We used Student’s t-tests to compare sexes and morphotypes’ measurements. We found at least three well-defined coat color morphotypes distinguishable by dorsal and ventral coloration and not restricted to PARNA Catimbau. Variation of the other morphological traits suggests that these morphotypes are more likely a case of intraspecific variation in the Brazilian northeastern region. Morphometric differences, particularly between coat color morphotypes, might be better elucidated in larger samples. Additionally, these specimens represent an important extension of the species’ known distribution reaching the Atlantic Forest borders. [ABSTRACT FROM AUTHOR]

Many insects, including several orthopterans, undergo dramatic changes in body coloration during ontogeny. This variation is particularly intriguing in gomphocerine grasshoppers, where the green and brown morphs appear to be genetically determined (Schielzeth & Dieker, 2020, BMC Evolutionary Biology, 20, 63; Winter et al., 2021, Heredity, 127, 66). A better understanding of how these color morphs develop during ontogeny can provide valuable insights into the evolution and ecology of such a widespread color polymorphism. Here, we focus on the color development of two green–brown polymorphic species, the club‐legged grasshopper Gomphocerus sibiricus and the steppe grasshopper Chorthippus dorsatus. By following the color development of individuals from hatching to adulthood, we found that color morph differences begin to develop during the second nymphal stage, are clearly defined by the third nymphal stage, and remain stable throughout the life of an individual. Interestingly, we also observed that shed skins of late nymphal stages are identifiable by color morphs based on their yellowish coloration, rather than the green that marks green body parts. Furthermore, by assessing how these colors are perceived by different visual systems, we found that certain potential predators can chromatically discriminate between morphs, while others may not. These results suggest that the putative genes controlling color morph are active during the early stages of ontogeny, and that green color is likely composed of two components, one present in the cuticle and one not. In addition, the effectiveness of camouflage appears to vary depending on the specific predator involved. [ABSTRACT FROM AUTHOR]

Betta splendens, Siamese fighting fish exhibit behavior, coloration, and morphology that make them popular aquarium fish in aquaculture. Coloration for this fish requires high-quality feeds rich in carotenoids. Crab shells, mostly dumped as agro-waste by the seafood industry contain carotenoids and protein that can be an alternative for carotenoids in fish feed. The objectives of this study were to analyze the proximate composition and carotenoid content in feed and determine the effect of crab shells as feedstuff on the growth performance and coloration of Betta splendens. A 40-day feeding trial using 45 tails of B. splendens with an average body weight, of 0.25 g was conducted by using five feed treatments namely TC (0% crab shell), T1 (25% crab shell), T2 (50% crab shell), T3 (75% crab shell) and T4 (100% crab shell) respectively. Sampling was done weekly. Analysis done were proximate composition and extraction of carotenoid while growth performance parameters such as body weight gain (BWG), specific growth rate (SGR), feed intake (FI), and feed conversion ratio (FCR) were also taken. Skin coloration and water quality data were collected every 10 days. All data were analyzed using One-Way ANOVA via SPSS. Results showed protein content for T1 (22.40±0.29) was slightly higher compared to all treatments. Carotenoid content in crab shells was lower compared to krill. Body weight from T1 (25% crab shell) showed a significant increase among all treatments. All treatments show no changes in coloration. In conclusion, T1 (25% crab shell waste) is the best treatment as it has a high protein content that improves body weight gain without any significant effect on coloration in all treatments. [ABSTRACT FROM AUTHOR]

Vertebrates exhibit a wide range of color patterns, which play critical roles in mediating intra- and interspecific communication. Because of their diversity and visual accessibility, color patterns offer a unique and fascinating window into the processes underlying biological organization. In this review, we focus on describing many of the general principles governing the formation and evolution of color patterns in different vertebrate groups. We characterize the types of patterns, review the molecular and developmental mechanisms by which they originate, and discuss their role in constraining or facilitating evolutionary change. Lastly, we outline outstanding questions in the field and discuss different approaches that can be used to address them. Overall, we provide a unifying conceptual framework among vertebrate systems that may guide research into naturally evolved mechanisms underlying color pattern formation and evolution. [ABSTRACT FROM AUTHOR]

Convergent evolution is defined as the independent evolution of similar phenotypes in different lineages. Its existence underscores the importance of external selection pressures in evolutionary history, revealing how functionally similar adaptations can evolve in response to persistent ecological challenges through a diversity of evolutionary routes. However, many examples of convergence, particularly among closely related species, involve parallel changes in the same genes or developmental pathways, raising the possibility that homology at deeper mechanistic levels is an important facilitator of phenotypic convergence. Using the genus Ranitomeya , a young, color-diverse radiation of Neotropical poison frogs, we set out to 1) provide a phylogenetic framework for this group, 2) leverage this framework to determine if color phenotypes are convergent, and 3) to characterize the underlying coloration mechanisms to test whether color convergence occurred through the same or different physical mechanisms. We generated a phylogeny for Ranitomeya using ultraconserved elements and investigated the physical mechanisms underlying bright coloration, focusing on skin pigments. Using phylogenetic comparative methods, we identified several instances of color convergence, involving several gains and losses of carotenoid and pterin pigments. We also found a compelling example of nonparallel convergence, where, in one lineage, red coloration evolved through the red pterin pigment drosopterin, and in another lineage through red ketocarotenoids. Additionally, in another lineage, "reddish" coloration evolved predominantly through structural color mechanisms. Our study demonstrates that, even within a radiation of closely related species, convergent evolution can occur through both parallel and nonparallel mechanisms, challenging the assumption that similar phenotypes among close relatives evolve through the same mechanisms. [ABSTRACT FROM AUTHOR]

Birds are known for their brilliant colors and extraordinary patterns. Sightings of individuals with atypical plumage often cause considerable excitement in the birding public, but receive little attention beyond reporting one-off sightings by the scientific community. In this Perspective, we argue that sightings of individuals with atypical plumage submitted to community science platforms hold the potential to further our understanding of the evolution of plumage color and patterning in birds. As a demonstration, we outline two examples using sightings of leucistic individuals--those that lack melanin across the body or in certain feather patches. First, we discuss the potential for understanding carotenoid pigmentation with these sightings. Leucism influences melanins, but not carotenoids, and so the extent and distribution of carotenoids across the body are unmasked. In a leucistic individual, carotenoids may or may not be more extensive than what is typically visible and this could help to understand the energetic costs and constraints involved in obtaining, processing, and depositing carotenoids in different species. Second, we discuss how partial leucism could provide insights into plumage pattern evolution. We demonstrate that one can use the many observations present on community science platforms to identify repeated patterns in different partially leucistic individuals of the same species, and match these to patches present in related species. These patterns could be the result of shared underlying genetic variation that controls plumage patterning in birds over long evolutionary timescales. With these examples, we outline a few potential lines of inquiry possible with atypical sightings submitted to community science platforms and note that other plumage aberrations provide additional opportunities. We encourage researchers to take full advantage of these chance sightings when they occur and database managers to make it possible to more easily tag photos of individuals with atypical plumage or other traits. [ABSTRACT FROM AUTHOR]

Polymorphism has been described in many avian taxa including Ardeidae. This study investigated the spatio-temporal distribution of color polymorphic forms (with regard to the color of the unfeathered parts (legs/lores)) of the Great White Egret Ardea alba alba in internet images from Europe. In total, 140 images of presumed polymorphs from 16 countries (from 2006 to 2021) have been collected and examined. Eight coloration schemes of visible unfeathered parts were distinguished. Since some polymorphs may represent the subspecies Eastern Great Egret Ardea alba modesta, the ratio of beak length to total head length was compared among individuals representing the nominal and Eastern Great Egret subspecies. The ratio distributions were similar in all compared groups; thus, polymorph egrets may represent both of these subspecies. Most polymorph images originate from the Netherlands and the southwestern Norwegian coast. This may have resulted from specific local diets and contact with hormone-disrupting compounds. Nevertheless, some observation biases, such as the presence of local breeding population or high numbers of nature photographers, could have affected our observation pattern. Some analyzed features also followed temporal patterns. Most polymorphs were observed during the breeding season, suggesting disruptions of sex hormones as a possible cause. Studies of spatio-temporal patterns of polymorph occurrence may allow us to obtain insights into the causes of large variation in coloration schemes in polymorphic species. [ABSTRACT FROM AUTHOR]

Cobalt blue ceramic pigments mainly consisting of CoAl2O4 are subject to the difficulty of color control. Here, a perspective is reported regarding research on the reasons for color change based on the control of the heat treatment and ratio of components. Macroscopically, the composition of pigment powders determines the color. Microscopically, the crystallite characters including size, cation distribution, and structure have an important effect on the color. The ingredient, structural, and color properties of the pigment powders are analyzed using thermo gravimetry–differential scanning calorimetry (TG–DSC), X-ray diffraction (XRD) measurement, Rietveld refinement, energy dispersive spectrometer (EDS), and colorimetry analysis. The color is proven to be associated with cation distribution, such as that of Co2+ and Co3+. It is indicated that high heating temperature, long heating time, and a large proportion of Al3+ can, respectively, induce the Co2+ and Al3+ in tetrahedral and octahedral sites. [ABSTRACT FROM AUTHOR]

To elucidate the molecular mechanisms underlying the differential metabolism of albino (white), green, and purple pericarp coloration, biochemical profiling and transcriptome sequencing analyses were performed on three different tea pericarps, Zhongbaiyihao (Camellia sinensis L. var. Zhongbai), Jinxuan (Camellia sinensis L. var. Jinxuan), and Baitangziya (Camellia sinensis L. var. Baitang). Results of biochemical analysis revealed that low chlorophyll content and low chlorophyll/carotene ratio may be the biochemical basis for albino characteristics in the 'Zhongbaiyihao' pericarp. The differentially expressed genes (DEGs) involved in anthocyanin biosynthesis, including DFR, F3′5′H, CCoAOMT, and 4-coumaroyl-CoA, were highly expressed in the purple 'Baitangziya' pericarp. In the chlorophyll synthesis of white pericarp, GUN5 (Genome Uncoupled 5) and 8-vinyl-reductase both showed high expression levels compared to the green one, which indicated that albino 'Zhongbaiyihao' pericarp had a higher chlorophyll synthesis capacity than 'Jinxuan'. Meanwhile, chlorophyllase (CLH, CSS0004684) was lower in 'Baitang' than in 'Jinxuan' and 'Zhongbaiyihao' pericarp. Among the differentially expressed transcription factors, MYB59, WRKY41-like2 (CS ng17509), bHLH62 like1 (CS ng6804), and bHLH62-like3 (CSS0039948) were downregulated in Jinxuan pericarp, suggesting that transcription factors played a role in regulating tea pericarp coloration. These findings provide a better understanding of the molecular mechanisms and theoretical basis for utilizing functional components of tea pericarp. [ABSTRACT FROM AUTHOR]

Camouflage is a common trait enabling animals to avoid detection by predators and prey. Patterns such as spots and stripes are convergent across carnivore families, including felids, and are hypothesized to have adaptive value through camouflage. House cats (Felis catus) were domesticated thousands of years ago, but despite artificial selection for a wide variety of coat colors, the wild‐type pattern of tabby cats is very common. We aimed to determine whether this pattern grants an advantage over other morphs in natural environments. We collected cat images taken with camera traps in natural areas near and far from 38 rural settlements in Israel, to compare the habitat use by feral cats of different colors. We tested the effect of proximity to villages and habitat vegetation (normalized difference vegetation index, NDVI) on the probability of space use by the tabby morph compared to the others. NDVI had a positive effect on site use in both morphs, but non‐tabby cats had a 2.1 higher probability of using the near sites than the far sites, independent of NDVI. The wild‐type tabby cats' probability of site use were equally likely to be unaffected by proximity, or have an interaction of proximity with NDVI whereby the far transects are used with increasing probability in sites of denser vegetation. We hypothesize that the camouflage of tabby cats, more than other colors and patterns, confers an advantage in roaming the woodland habitats for which this pattern evolved. This has both theoretical implications as rare empirical evidence of the adaptive value of fur coloration, and practical implications on managing the ecological impact of feral cats worldwide. [ABSTRACT FROM AUTHOR]

Protective coloration is observed in numerous extant cockroach species and is prevalent among insects. Such coloration can signal nonprofitability of prey (aposematic) or serve as a camouflage (disruptive). An apparent aposematic isolated macula is identified here among the cockroach Facioblatta perfidia gen. et sp. n. (Liberiblattinidae) from Northern Myanmar amber. In total, 9 and 10 general coloration patterns related to spot-like patterns among extant and fossil species, respectively, are identified. Potential cockroach predators targeted with these patterns varied from dragonflies, small Jurassic pterosaurs and lizards, to Cretaceous and modern frogs, birds and insectivores. Patterns asynchronously appeared throughout the taxonomic spectrum suggesting that the elimination from predators combined with environmental factors influenced the spread of protective coloration among cockroaches. [ABSTRACT FROM AUTHOR]

Numerous hypotheses try to explain the unusual appearance of the human eye with its bright sclera and transparent conjunctiva and how it could have evolved from a dark-eyed phenotype, as is present in many non-human primates. Recently, it has been argued that pigmentation defects induced by self-domestication may have led to bright-eyed ocular phenotypes in humans and some other primate lineages, such as marmosets. However, it has never been systematically studied whether actual domesticated mammals consistently deviate from wild mammals in regard to their conjunctival pigmentation and if this trait might therefore be part of a domestication syndrome. Here, we test this idea by drawing phylogenetically informed comparisons from a photographic dataset spanning 13 domesticated mammal species and their closest living wild relatives (n ≥ 15 photos per taxon). We did not recover significant differences in scleral appearance or irido-scleral contrast between domesticated and wild forms, suggesting that conjunctival depigmentation, unlike cutaneous pigmentation disorders, is not a general correlate of domestication. Regardless of their domestication status, macroscopically depigmented conjunctivae were observed in carnivorans and lagomorphs, whereas ungulates generally displayed darker eyes. For some taxa, we observed pronounced intraspecific variation, which should be addressed in more exhaustive future studies. Based on our dataset, we also present preliminary evidence for a general increase of conjunctival pigmentation with eye size in mammals. Our findings suggest that conjunctival depigmentation in humans is not a byproduct of self-domestication, even if we assume that our species has undergone such a process in its recent evolutionary history. [ABSTRACT FROM AUTHOR]

With novel human–wildlife interaction, predation regimes, and environmental conditions, in addition to often fragmented and smaller populations, urban areas present wildlife with altered natural selection parameters and genetic drift potential compared with nonurban regions. Plumage and pelage coloration in birds and mammals has evolved as a balance between avoiding detection by predator or prey, sexual selection, and thermoregulation. However, with altered mutation rates, reduced predation risk, increased temperatures, strong genetic drift, and increased interaction with people, the evolutionary contexts in which these colorations arose are radically different from what is present in urban areas. Regionally alternative color morphs or leucistic or melanistic individuals that aren't typical of most avian or mammalian populations may become more frequent as a result of adaptive or neutral evolution. Therefore, I conceptualize that, in urban areas, conspicuous color morphologies may persist, leading to an increase in the frequency of regionally atypical pelage coloration. In the present article, I discuss the potential for conspicuous color morphs to arise and persist in urban mammalian and avian populations, as well as the mechanisms for such persistence, as a result of altered environmental conditions and natural selection pressures. [ABSTRACT FROM AUTHOR]

A new salamander species of the genus Bolitoglossa is here described from the cloud forests of the western slopes of the Cordillera Oriental of Colombia, in the Cundinamarca department. The most salient characters of this new species are its numerous maxillary and vomerine teeth, its moderate webbing on hands and feet, its short and robust tail, and its chromatic variation. Based on molecular analyses this new species is assigned to the adspersa species group and its status established as the sister species of B. adspersa, with which it was previously confused. Lastly, the distribution, natural history, and conservation status of the new species are discussed. [ABSTRACT FROM AUTHOR]

Coral reef fishes are diverse in ecology and behaviour and show remarkable colour variability. Investigating the visual pigment gene (opsin) expression in these fishes makes it possible to associate their visual genotype and phenotype (spectral sensitivities) to visual tasks, such as feeding strategy or conspecific detection. By studying all major damselfish clades (Pomacentridae) and representatives from five other coral reef fish families, we show that the long‐wavelength‐sensitive (lws) opsin is highly expressed in algivorous and less or not expressed in zooplanktivorous species. Lws is also upregulated in species with orange/red colours (reflectance >520 nm) and expression is highest in orange/red‐coloured algivores. Visual models from the perspective of a typical damselfish indicate that sensitivity to longer wavelengths does enhance the ability to detect the red to far‐red component of algae and orange/red‐coloured conspecifics, possibly enabling social signalling. Character state reconstructions indicate that in the early evolutionary history of damselfishes, there was no lws expression and no orange/red coloration. Omnivory was most often the dominant state. Although herbivory was sometimes dominant, zooplanktivory was never dominant. Sensitivity to long wavelength (increased lws expression) only emerged in association with algivory but never with zooplanktivory. Higher lws expression is also exploited by social signalling in orange/red, which emerged after the transition to algivory. Although the relative timing of traits may deviate by different reconstructions and alternative explanations are possible, our results are consistent with sensory bias whereby social signals evolve as a correlated response to natural selection on sensory system properties in other contexts. [ABSTRACT FROM AUTHOR]

Phenacorhamdia nigrolineata is redescribed, and the expansion of its geographic distribution is presented based on abundant new records. Morphological analysis, meristic comparison and osteological description were performed. No one autapomorphy was identified for P. nigrolineata, but the species is identified by an exclusive combination of characters of coloration of the body, morphometric and meristic data (snout length, maxillary and outer mental barbels length; number of vertebrae). A discussion of its geographic distribution, coloration pattern of the body, the putative relationships among some species of the genus, and its conservation status are presented. [ABSTRACT FROM AUTHOR]

Currently, in a market economy, there are a number of problems that impede the improvement of the quality of karakul. One of them is the need to improve effective methods of selection and breeding, taking into account the characteristics of karakul sheep, in-depth study of the histomorphological structures of the skin and wool of lambs of different colors and increase the productivity of karakul sheep. The purpose of this study is to study the histomorphological features of lambs of different colors of the jacket-type lambs obtained from gray karakul sheep. According to the results of the study, in dark gray lambs of the mother-of-pearl jacket type, the thickness of the reticular layer of the skin was 532.2; in dark gray lambs -- 537.7 microns, or by 43.4% (8.78%) and 46.5 (9.47%) are fatter than light gray milky and medium gray jacket blue lambs (P < 0.05). It can be seen that the diameter of the secondary hair follicles in lead-colored medium-gray lambs is 1.48% and 7.44% thicker than in steel-colored and blue-colored dark gray lambs, respectively. The coefficient of deviation of the diameter of hair secondary hair follicles ranged from Cv = 15.6-20.5. According to the number of secondary hair follicles, it can be seen that in lambs of light gray color of steel of the jacket type, it is 6.04% and 9.79% more than in lambs of light gray color of blue and mother-of-pearl colors (P<0.05). According to the ratio of the number of sweat and sebaceous glands (SG/SG), it was found that in light gray lambs it is in the range of 1.90-1.95 pieces, in medium gray lambs 1.95-2.03 and in dark gray lambs 1.89-1.91. [ABSTRACT FROM AUTHOR]

Simple Summary: The leopard coralgrouper (Plectropomus leopardus) is highly valuable in the ornamental fish market owing to its bright red color. Astaxanthin is commonly used as a red colorant in aquaculture. To investigate the genetic basis of red color formation in P. leopardus, we compared the effects of natural and synthetic astaxanthin on P. leopardus color and transcriptome and metabolome profiles. Natural astaxanthin had a superior effect on color compared to that of synthetic astaxanthin, as evidenced by increases in redness and yellowness. Carotenoid- and melanin-related genes were differentially expressed between groups treated with natural astaxanthin, synthetic astaxanthin, and no astaxanthin. These results provide a theoretical basis for color enhancement during the culture of P. leopardus. Natural and synthetic astaxanthin can promote pigmentation in fish. In this study, the effects of dietary astaxanthin on growth and pigmentation were evaluated in leopard coralgrouper (Plectropomus leopardus). Fish were assigned to three groups: 0% astaxanthin (C), 0.02% natural astaxanthin (HP), and 0.02% synthetic astaxanthin (AS). Brightness (L*) was not influenced by astaxanthin. However, redness (a*) and yellowness (b*) were significantly higher for fish fed astaxanthin-containing diets than fish fed control diets and were significantly higher in the HP group than in the AS group. In a transcriptome analysis, 466, 33, and 32 differentially expressed genes (DEGs) were identified between C and HP, C and AS, and AS and HP, including various pigmentation-related genes. DEGs were enriched for carotenoid deposition and other pathways related to skin color. A metabolome analysis revealed 377, 249, and 179 differential metabolites (DMs) between C and HP, C and AS, and AS and HP, respectively. In conclusion, natural astaxanthin has a better coloration effect on P. leopardus, which is more suitable as a red colorant in aquaculture. These results improve our understanding of the effects of natural and synthetic astaxanthin on red color formation in fish. [ABSTRACT FROM AUTHOR]

Background matching camouflage enables animals to evade detection with colours and patterns that resemble and blend into the environment. Effective concealment can, however, be difficult to achieve as natural backgrounds are often heterogeneous and frequently made up of spatially distinct microhabitats that differ in their visual characteristics. Many species make use of multiple microhabitat patches, and the ways in which an animal exploits different microhabitats will likely vary throughout its life cycle as behaviour, morphology and predation risk change. Here, we used the Fowler's toad, Anaxyrus fowleri , and its lakeshore habitat to investigate how camouflage changes throughout ontogeny in relation to a series of spatially structured microhabitats. These toads are predominantly light beige in colour with a haphazard pattern of brown spots. This pattern is consistent throughout life, and spot size scales along with increasing body size. We modelled how well toad colour and patterning matched each background as perceived by bird, snake and mammal predators. We predicted that background matching would be targeted to the microhabitats where toads are most likely to be found during the day and that camouflage would be most effective at the most vulnerable (i.e. younger) life stages. We found that toad colour was specialized to match the dry sandy beach microhabitats where the toads were most frequently encountered and that pattern matching varied depending on toad size. We found that the small spots of juvenile toads best matched areas of bare sand whereas the correspondingly large spots of adult toads best matched larger items of beach debris such as broken shells, pebbles and fragments of wood. Taken together, our data suggest that, as toads grow larger, background matching camouflage remains effective, and that juveniles and adults use the same pattern to match different components within the heterogenous background. • In variable environments, camouflage can either be specialized or generalized. • Changes in body size can affect the efficacy of specialist or generalist camouflage. • Fowler's toad camouflage is specialized to behaviourally important microhabitats. • As Fowler's toads grow, their coloration matches different parts of the background. • Understanding camouflage requires defining both the spatial and temporal context. [ABSTRACT FROM AUTHOR]

Aim: To predict future colour–climate relationships, it is important to distinguish thermal drivers of reflectance from other evolutionary drivers. We aimed to achieve this by comparing relationships between climate and coloration in ultraviolet–visible (UV–Vis) and near‐infrared (NIR) light, separately. Location: Samples were distributed primarily across Australia and North America, with some from Africa and Asia. Major taxa studied: Coleoptera: Buprestidae. Methods: We used jewel beetles as models to identify climatic drivers of reflectance, because jewel beetles have highly diverse coloration and a wide distribution and are often active in hot conditions. Specifically, we tested the association between climate, body size and reflectance using a phylogenetic comparative analysis for three wavebands (UV–Vis, NIR and total). Results: Reflectance of jewel beetles was more strongly predicted by body size than by climate. NIR reflectance and total reflectance were not associated with climate, but larger beetles had higher NIR reflectance. For UV–Vis reflectance, small beetles were darker in warmer and more humid environments, whereas there was no association with climate for large beetles. Main conclusions: Our study suggests that variation in reflectance of jewel beetles is not driven by thermal requirements and highlights the importance of considering NIR reflectance when evaluating explanations of the effects of colour on thermoregulation. [ABSTRACT FROM AUTHOR]

Pigmentation is one of the most striking examples of diversity in the natural world. Specifically, primate pelage (hair/fur) pigmentation provides a substrate for selection, and is tied to functions such as crypsis, signaling, and thermoregulation. However, most of our hypotheses on the forces responsible for primate pelage pigmentation are based solely on macro-evolutionary studies. Here, we test how distinct hypotheses around climate, age, and sex might be influencing pelage color variation in a wild primate population. We characterize pelage color and pattern variation within a population of wild diademed sifakas (Propithecus diadema) exhibiting striking diversity in coloration (melanic to tri-colored). Our approach jointly assesses climate and pelage variation across the region. We score pelage using a semi-quantitative methodology (n = 87 individuals). We then test if pelage variation is associated with climatic or demographic factors (i.e., sex–class, age–class) across the Tsinjoarivo forest, Madagascar. We find darker bodies and greater facial complexity in colder and more fragmented forests. We conclude that three explanations may explain the phenotypic pattern: isolation by distance, an environmental gradient, or local adaptation. Although it is difficult to reach a causal conclusion without genetic data, each scenario signals the need for enhanced conservation of diademed sifakas in the Tsinjoarivo forest. More studies on primate pigmentation in wild populations will be needed to contextualize if this pattern is exceptional or typical. We argue that primate color in wild populations may also foretell either adaptation or maladaptation (i.e., via environmental mismatch). [ABSTRACT FROM AUTHOR]