Bare Parts Research Articles

Bare parts in the Galliformes: the evolution of a multifunctional structure.

A morphological trait can have multiple functions shaped by varying selective forces. Bare parts in birds, such as wattles, casques and combs, are known to function in both signalling and thermoregulation. Studies have demonstrated such structures are targets of sexual selection via female choice in several species of Galliformes (junglefowl, turkeys and grouse), though other studies have shown some role in thermoregulation (guineafowl). Here, we tested fundamental hypotheses regarding the evolution and maintenance of bare parts in Galliformes. Using a phylogeny that included nearly 90% of species in the order, we evaluated the role of both sexual and natural selection in shaping the function of bare parts across different clades. We found a combination of both environmental and putative sexually selected traits strongly predicted the variation of bare parts for both males and females across Galliformes. When the analysis is restricted to the largest family, Phasianidae (pheasants, junglefowl and allies), sexually selected traits were the primary predictors of bare parts. Our results suggest that bare parts are important for both thermoregulation and sexual signalling across Galliformes but are primarily under strong sexual selection within the Phasianidae.

Further observations of a Black Falcon Falco subniger with yellow bare parts

I describe and provide photographs of a typically dark-plumaged Black Falcon Falco subniger that had yellow bare parts – cere, base of lower mandible, orbital skin and feet – observed in the field near Oakey, in inland Queensland, in July 2024.

Another Black Falcon Falco subniger with yellow bare parts

We describe and illustrate a Black Falcon Falco subniger, observed in the field near Milparinka in outback New South Wales in May 2024, that had yellow bare parts. Following our online posts that generated debate on the bird’s identity, and referral to raptor enthusiasts and experts, we here document the case and briefly review relevant background and questions for further investigation.

Bare-throated spurfowl (Pternistis spp.) males across Africa impress females with bright throat colours during courtship

The role of bare body parts in sexual signalling in birds has received relatively little attention. I describe how the bare-throated spurfowl males saturate the colours of their throats to attract females. Of the 23 Afrotropical spurfowl species, the bare-throated subgroup includes Yellow-necked Spurfowl (Pternistis leucosceptus), Red-necked Spurfowl (P. afer), Grey-breasted Spurfowl (P. rufopictus) and Swainson's Spurfowl (P. swainsonii). The rest of the species include fully feathered throated spurfowls. Throat colour intensity of bare throats was scored using an extensive online digital photographic archive encompassing the four species across the year's seasons. Each throat (n ​= ​836) was assigned to one of four colour-intensity categories to explore the relationship between colour intensities, breeding cycles, and environmental variation. Except for Swainson's Spurfowl male saturation of throat colours correlated with monthly rainfall, which peaks one or two months before egg laying. Swainson's Spurfowl peaks during egg laying. Yellow-necked Spurfowl has the largest bare throat. Bare-throated spurfowl males perform an elevated courtship display posture above the female to feature their throat colour. No such displays occur in feather-throated spurfowl. Males with low throat colour saturation harbour more ectoparasites on their bare throats than birds with saturated throats. Male Red-necked Spurfowls have significantly larger bare throats than females. The primary function of bare throats probably assists in thermoregulation, particularly in arid regions. The bare throat may have evolved a secondary role in mating. Yellow-necked, Red-necked, and Grey-breasted Spurfowls use their saturated throat colours as ornaments to court females during the breeding season. Unobtrusive female throat colours (unsaturated) may discourage male interlopers and predation during egg laying. Saturation appears to be carotenoid-food based. The different colours among the bare-throated species may serve as prezygotic mechanisms that inhibit cross-breeding and explain why females also have coloured throats.

Abnormal Plumage in Adult Common Terns Sterna hirundo during the Breeding Season

Some bird species change their plumage colour on a seasonal basis, mostly between cryptic non-breeding plumage and conspicuous breeding plumage. Adult Common Terns Sterna hirundo moult their body feathers twice each year, resulting in two types of plumages, those typical to breeding and non-breeding seasons, which exhibit minor differences in the colours of some feathers, as well as the bare parts. Here, we report evidence of an abnormal plumage in adult Common Terns (sometimes referred to as ‘portlandica’), with two individuals exhibiting non-breeding like plumage during the breeding season. These terns were documented in a breeding colony in Northern Israel. This report could lead to future research into the causes and consequences of plumage maturation avoidance in adult birds.

Aster la vista: Unraveling the biochemical basis of carotenoid homeostasis in the human retina.

Carotenoids play pivotal roles in vision as light filters and precursor of chromophore. Many vertebrates also display the colorful pigments as ornaments in bare skin parts and feathers. Proteins involved in the transport and metabolism of these lipids have been identified including class B scavenger receptors and carotenoid cleavage dioxygenases. Recent research implicates members of the Aster protein family, also known as GRAM domain-containing (GRAMD), in carotenoid metabolism. These multi-domain proteins facilitate the intracellular movement of carotenoids from their site of cellular uptake by scavenger receptors to the site of their metabolic processing by carotenoid cleavage dioxygenases. We provide a model how the coordinated interplay of these proteins and their differential expression establishes carotenoid distribution patterns and function in tissues, with particular emphasis on the human retina.

Oxidative physiology is weakly associated with pigmentation in birds

The mechanistic link between avian oxidative physiology and plumage coloration has attracted considerable attention in past decades. Hence, multiple proximal hypotheses were proposed to explain how oxidative state might covary with the production of melanin and carotenoid pigments. Some hypotheses underscore that these pigments (or their precursors, e.g., glutathione) have antioxidant capacities or function as molecules storing the toxic excess of intracellular compounds, while others highlight that these pigments can act as pro‐oxidants under specific conditions. Most studies addressing these associations are at the intraspecific level, while phylogenetic comparative studies are still scarce, though needed to assess the generality of these associations. Here, we tested whether plumage and bare part coloration were related to oxidative physiology at an interspecific level by measuring five oxidative physiology markers (three nonenzymatic antioxidants and two markers of lipid peroxidative damage) in 1387 individuals of 104 European bird species sampled during the breeding season, and by scoring plumage eumelanin, pheomelanin, and carotenoid content for each sex and species. Only the plasma level of reactive oxygen metabolites was related to melanin coloration, being positively associated with eumelanin score and negatively with pheomelanin score. Thus, our results do not support the role of antioxidant glutathione in driving variation in melanin synthesis across species. Furthermore, the carotenoid scores of feathers and bare parts were unrelated to the measured oxidative physiology parameters, further suggesting that the marked differences in pigmentation across birds does not influence their oxidative state.

Exposure to phthalates in the sleeping microenvironment of university dormitories: A preliminary estimate based on skin wipe and dust sampling

Since synthetic materials that might contain phthalates are widely used to fabricate bedding and decorating materials, phthalates are typical pollutants in sleeping microenvironments. Although people spend more than 30% of time sleeping, exposure to phthalates in sleeping microenvironments has not been well characterized. In this study, we measured the occurrence of six commonly-used phthalates (dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), butyl benzyl phthalate (BBzP), di-2-ethylhexyl phthalate (DEHP), and di-n-octyl phthalate (DOP)) from skin wipes and settled dust in the sleeping microenvironment of university dormitories. Targeted phthalates were frequently detected (more than 80%) except for DEP (30%–58% and 70% for dermal and dust samples, respectively); and DnBP and DEHP predominated in all samples. Accumulated phthalates on skin surfaces were at similar levels on bare body parts (i.e., hands vs. forearms) during sleeping time. Phthalates in settled dust were significantly correlated with those detected from skin wipes. The estimated average daily intakes of studied phthalates (via inhalation and dermal absorption) ranged from 0.24 μg/kg/day to 1.12 μg/kg/day in the sleeping microenvironment of university dormitories (with the highest doses for DMP and DnBP). Exposure via dermal pathway contributed 38% and 64%, respectively for DMP and DEP, and over 80% for other phthalates during sleeping time. This study provides better understanding of phthalate transport, exposure, and associated control strategies in sleeping microenvironments.

Morphological variation in the Black Falcon Falco subniger

We describe and discuss a field observation of a strongly speckle-breasted and barred Black Falcon Falco subniger that also, unusually, had yellow feet and cere and pale-yellow orbital rings. We also found several museum specimens with ‘variegated’ plumage and yellow bare parts. We speculate that yellow bare parts in this species might occur only in some individuals, perhaps mostly males, of the most variegated (pale-marked) plumage types, and that these correlated features may be age-related characters that deserve further investigation. We also discuss the implications for field identification.

RECORD OF ABERRANT PLUMAGE IN Cyclarhis gujanensis (AVES: VIREONIDAE) IN SOUTHERN BRAZIL

Cases of birds with aberrant coloring are not an uncommon sight in the wild, but they need to be documented in specialized literature. These abnormalities may be associated with distinct factors, which can be environmental, genetic, food, diseases, exposure to parasites and age, causing increase and/or reduction of melanin, such as carotenism, in the affected species. We are presenting a report of Rufous-browed Peppershrike (Cyclarhis gujanensis) with aberrant coloring in southern Brazil. The specimen had some feathers in the head’s region depigmented to a whitish hue, mixed with feathers presenting regular coloring. Other bare parts and the remaining plumage present normal color. The report is about progressive graying, in what we believe is the first record of aberrant coloring for C. gujanensis through its known distribution.

Avian Coloration Genetics: Recent Advances and Emerging Questions.

The colorful phenotypes of birds have long provided rich source material for evolutionary biologists. Avian plumage, beaks, skin, and eggs-which exhibit a stunning range of cryptic and conspicuous forms-inspired early work on adaptive coloration. More recently, avian color has fueled discoveries on the physiological, developmental, and-increasingly-genetic mechanisms responsible for phenotypic variation. The relative ease with which avian color traits can be quantified has made birds an attractive system for uncovering links between phenotype and genotype. Accordingly, the field of avian coloration genetics is burgeoning. In this review, we highlight recent advances and emerging questions associated with the genetic underpinnings of bird color. We start by describing breakthroughs related to 2 pigment classes: carotenoids that produce red, yellow, and orange in most birds and psittacofulvins that produce similar colors in parrots. We then discuss structural colors, which are produced by the interaction of light with nanoscale materials and greatly extend the plumage palette. Structural color genetics remain understudied-but this paradigm is changing. We next explore how colors that arise from interactions among pigmentary and structural mechanisms may be controlled by genes that are co-expressed or co-regulated. We also identify opportunities to investigate genes mediating within-feather micropatterning and the coloration of bare parts and eggs. We conclude by spotlighting 2 research areas-mechanistic links between color vision and color production, and speciation-that have been invigorated by genetic insights, a trend likely to continue as new genomic approaches are applied to non-model species.

Instance Segmentation to Estimate Consumption of Corn Ears by Wild Animals for GMO Preference Tests.

The Genetically Modified (GMO) Corn Experiment was performed to test the hypothesis that wild animals prefer Non-GMO corn and avoid eating GMO corn, which resulted in the collection of complex image data of consumed corn ears. This study develops a deep learning-based image processing pipeline that aims to estimate the consumption of corn by identifying corn and its bare cob from these images, which will aid in testing the hypothesis in the GMO Corn Experiment. Ablation uses mask regional convolutional neural network (Mask R-CNN) for instance segmentation. Based on image data annotation, two approaches for segmentation were discussed: identifying whole corn ears and bare cob parts with and without corn kernels. The Mask R-CNN model was trained for both approaches and segmentation results were compared. Out of the two, the latter approach, i.e., without the kernel, was chosen to estimate the corn consumption because of its superior segmentation performance and estimation accuracy. Ablation experiments were performed with the latter approach to obtain the best model with the available data. The estimation results of these models were included and compared with manually labeled test data with R 2 = 0.99 which showed that use of the Mask R-CNN model to estimate corn consumption provides highly accurate results, thus, allowing it to be used further on all collected data and help test the hypothesis of the GMO Corn Experiment. These approaches may also be applied to other plant phenotyping tasks (e.g., yield estimation and plant stress quantification) that require instance segmentation.

Vegetation Growth Status and Topographic Effects in the Pisha Sandstone Area of China

Fractional vegetation coverage (FVC) plays an important role in monitoring vegetation growth status and evaluating restoration efforts in ecological environments. In this study, FVC was calculated using a binary pixel model and analyzed in the Pisha Sandstone area of China, using MODIS-EVI data from 2000 to 2019. Topographic effects were analyzed from elevation, slope and aspect using a terrain niche index model. The results were as follows. (1) From 2000 to 2019, FVC in the Pisha Sandstone area of China gradually increased at a mean rate of 0.0074/a, and the growth status of vegetation gradually improved. (2) The spatial distribution of FVC steadily decreased from southeast to northwest. FVC was the lowest in bare parts of the Pisha Sandstone area, whereas those in the sand- and soil-covered parts were the middle and highest, respectively. (3) With increasing elevation, the inferior coverage area and terrain niche index increased, and inferior coverage distribution changed from non-dominant to dominant. Meanwhile, the low, medium and high coverage areas decreased, and their distributions changed from dominance to non-dominance. (4) With increasing slope, distributions of the inferior, medium and high coverage areas changed from dominant to non-dominant, while the low coverage area had a dominant distribution. (5) Analyses of aspect effects revealed that the inferior coverage area was the dominant distribution in shady slopes but was non-dominant in semi-shady, semi-sunny and sunny slopes. The low, medium and high coverage areas were non-dominant in shady slopes, but dominant in semi-shady, semi-sunny and sunny slopes.

2D Thin Sheet Heterostructures of MoS2 on MoSe2 as Efficient Electrocatalyst for Hydrogen Evolution Reaction in Wide pH Range.

Two-dimensional layered transition metal dichalcogenides, MoSe2 and MoS2, have drawn potential attention in the field of water splitting. Coupling of MoS2 and MoSe2 provides a sustainable route to improve the electrocatalytic activity for the hydrogen evolution reaction (HER). Here, the heterostructures of thin sheets (ts) of MoSe2 and MoS2 are combined to develop the MoSe2-ts@MoS2-ts heterostructure via multiple-step methodology. First, thin sheets of MoSe2 are synthesized following the stepwise hydrothermal method. After the successful synthesis of MoSe2-ts, MoS2-ts is synthesized on it to develop the heterostructure: MoSe2-ts@MoS2-ts. By tuning the amount of MoS2-ts and MoSe2-ts in the heterostructure separately, the optimum condition is obtained for HER. The unique heterostructure is efficient for HER under wide pH conditions like 1 M KOH, pH-7 phosphate buffer, 3.5% saline water, and finally 0.5 M H2SO4. MoSe2-ts@MoS2-ts can generate 10 mA/cm2 current density under the application of -0.186 V vs RHE with a low Tafel value of 71 mV/decade. The formation of the heterojunction plays an essential role in facilitating charge transportation. Furthermore, the heterostructure provides the more active sites for the adsorption of hydrogen to generate H2. An excess amount of any of the bare counter parts in the heterostructure leads to a decrease in electrocatalytic efficiency because of the lowered heterojuction formation. MoSe2-ts@MoS2-ts has very high stability during the electrocatalytic reaction, which is determined from 1000 consecutive cycles and a 24 h prolonged scan. MoSe2-ts@MoS2-ts can generate 147 μmol of H2 in ∼50 min of reaction time with 100% Faradaic efficiency.

Genetic Basis of De Novo Appearance of Carotenoid Ornamentation in Bare Parts of Canaries

Unlike wild and domestic canaries (Serinus canaria), or any of the three dozen species of finches in genus Serinus, the domestic urucum breed of canaries exhibits bright red bills and legs. This novel trait offers a unique opportunity to understand the mechanisms of bare-part coloration in birds. To identify the mutation producing the colorful phenotype, we resequenced the genome of urucum canaries and performed a range of analyses to search for genotype-to-phenotype associations across the genome. We identified a nonsynonymous mutation in the gene BCO2 (beta-carotene oxygenase 2, also known as BCDO2), an enzyme involved in the cleavage and breakdown of full-length carotenoids into short apocarotenoids. Protein structural models and in vitro functional assays indicate that the urucum mutation abrogates the carotenoid-cleavage activity of BCO2. Consistent with the predicted loss of carotenoid-cleavage activity, urucum canaries tended to have increased levels of full-length carotenoid pigments in bill tissue and reduced levels of carotenoid-cleavage products (apocarotenoids) in retinal tissue compared with other breeds of canaries. We hypothesize that carotenoid-based bare-part coloration might be readily gained, modified, or lost through simple switches in the enzymatic activity or regulation of BCO2 and this gene may be an important mediator in the evolution of bare-part coloration among bird species.

Effects of soil texture and groundwater level on leaching of salt from saline fields in Kesem irrigation scheme, Ethiopia

In Ethiopia, soil salinity has become a challenge for agricultural production in irrigated arid and semi-arid areas. This research investigates the effectiveness of leaching salt remediation under different soil textures and groundwater tables. Leaching was conducted in the bare parts of three abandoned saline fields. Soil texture of Field 1 (F1) is sandy loam while Field 2 (F2) and Field 3 (F3) are clay loam. The F1, F2, and F3 groundwater was located at 1.8, 1.5 and > 3 m, respectively. The leaching requirement water levels were 15, 20, 25, and 30% higher than the evaporation of the bare field needed for four consecutive weeks, respectively. The results of this study show that, after four days of leaching, the salinity of F1 with sandy loam texture was significantly (P < 0.05) and more strongly reduced than for the other fields exhibiting clay loam texture. For F1, salinity was reduced from 16.3 to 6.2 dS/m and from 12.4 to 5.5 dS/m at depths of 0–30 and 30–60 cm, respectively. In head parts of F1 and F3, the salinity level was reduced to 2.0 dS/m. However, in F2 with shallow groundwater and clay loam texture, the salinity levels were slightly higher after leaching, i.e. from 11.2 to 12.0 dS/m and from 8.1 to 11.6 dS/m at 0–30 and 30–60 cm depths, respectively. In our experiment, effective leaching was achieved only in the field with sandy soil and deeper groundwater table. We saw that the application of leaching with surface drainage at shallow groundwater levels may further exacerbate salinity problems. For such situations, the use of subsurface drainage could sustain the groundwater depth and prevent additional salinization. On clay-textured fields with shallow groundwater table, a prolonged leaching application is necessary to reduce the salt contents.

Divergent color signals from homologous unfeathered ornaments in two congeneric grouse.

Color‐based visual signals are important aspects of communication throughout the animal kingdom. Individuals evaluate color to obtain information about age and condition and to behave accordingly. Birds display a variety of striking, conspicuous colors and make ideal subjects for the study of color signaling. While most studies of avian color focus on plumage, bare unfeathered body parts also display a wide range of color signals. Mate choice and intrasexual competitive interactions are easily observed in lekking grouse, which also signal with prominent unfeathered color patches. Most male grouse have one pair of colorful bare part ornaments (combs), and males of several species also have inflatable air sacs in their throat. Previous studies have mostly focused on comb color and size, but little is known about the signaling role of air sac color. We measured comb size and the color properties of combs and air sacs in the Lesser and Greater Prairie‐Chickens (Tympanuchus pallidicinctus and T. cupido, respectively), and investigated whether these properties varied with age and mass. We found that mass predicted color properties of air sacs and that age predicted comb size in the Greater Prairie‐Chicken, suggesting that these ornaments indicate condition dependence. No conclusive relationships between color and age or size were detected in the Lesser Prairie‐Chicken. Color properties of both ornaments differed between the two species. Further research is needed to determine mechanisms that link condition to color and whether the information advertised by color signals from these ornaments is intended for males, females, or both.

Quantitative and semi-quantitative risk assessment of occupational exposure to lead among electrical solderers in Neyshabur, Iran.

Lead is one of the most widely used elements in the world. Lead can cause acute and chronic complications such as abnormal hemoglobin synthesis, kidney damage, abortion, nervous system disorders, male infertility, loss of learning ability, behavioral disorders, and even death. The aim of this study was to carry out quantitative and semi-quantitative risk assessments of exposure to lead among the solderers of the Neyshabur electronics industry. This cross-sectional, descriptive, and analytical study was conducted in 2017 and 2018 on 40 female soldering workers exposed to lead. Semi-quantitative risk assessment was carried out according to the Singapore Health Department and quantitative risk assessment according to the Office of Environmental Health Hazard Assessment (OEHHA) method. The average occupational exposure to lead in the electronics manufacturing industry was 93.89 ± 33.40 μg m-3 with a range from 9 to 150 μg m-3. Occupational exposure to lead in the industrial groups of initial soldering with an average of 130.37 ± 40.23 μg m-3 and cutting wires, electroplating, and coating bare parts with an average of 110.24 ± 30.11 μg m-3 was higher than the secondary soldering groups with an average of 90.78 ± 20.22 and shift supervisors with an average of 43.86 ± 10.97 μg m-3. The mean excess lifetime cancer risk (ELCR) was 0.11 per 1000 people and the mean non-carcinogenic risk (HQ) was 7.20. The results of this study indicate that there is a risk of non-carcinogenic complications among electronic solderers. Therefore, managers and employers should reduce lead exposure through engineering controls (substituting lead-free alloys, efficient ventilation) and management strategies such as reducing exposure hours.

Carotenoid-based coloration predicts both longevity and lifetime fecundity in male birds, but testosterone disrupts signal reliability.

Sexual selection promotes the evolution of conspicuous animal ornaments. To evolve as signals, these traits must reliably express the “quality” of the bearer, an indicator of individual fitness. Direct estimates of individual fitness may include the contribution of longevity and fecundity. However, evidence of a correlation between the level of signal expression and these two fitness components are scarce, at least among vertebrates. Relative fitness is difficult to assess in the wild as age at death and extra-pair paternity rates are often unknown. Here, in captive male red-legged partridges, we show that carotenoid-based ornament expression, i.e., redness of the bill and eye rings, at the beginning of reproductive life predicts both longevity (1–7 years) and lifetime breeding output (offspring number and hatching success). The recently proposed link between the individual capacity to produce red (keto) carotenoid pigments and the efficiency of cell respiration could, ultimately, explain the correlation with lifespan and, indirectly, fecundity. Nonetheless, in males of avian species, carotenoid-based coloration in bare parts is also partially controlled by testosterone. We also manipulated androgen levels throughout life by treating males with testosterone or antiandrogen compounds. Treatments caused correlations between signal levels and both fitness components to disappear, thus making the signals unreliable. This suggests that the evolution of carotenoid-based sexual signals requires a tightly-controlled steroid metabolism.

Luehea candicans Increase In Vitro Cell Cancer Metabolism Even with High Polyphenols Content

Brazil is the country with the greatest biodiversity; however, most of the plants are used empirically, without scientific evidence. Luehea candicans, popularly called as-acoita-cavalo, is a specie characteristic of the Brazilian Cerrado Biome, used for fight hemorrhages, dysenteries, diarrhea, rheumatism and tumors. On the other hands, there are practically no studies about chemical composition and assess of their biological effects. Thus, the aim of this investigation was characterize and evaluate the antitumor potential of crude hydroethanolic extract from the bare stem parts of this plant, as well as its ethyl acetate and methanolic fractions. For the characterization, the crude extract was submitted to qualitative (phytochemical screening and analysis by direct flow injection by mass spectrometry-FIA-ESI-IT-MS) and quantitative tests (determination of phenolic compounds and determination of total flavonoids and anthocyanins). In order to study the antitumor potential, MTT technique was used to evaluate the cellular metabolism of canine breast cancer tumor cells (TCM) and osteosarcoma (OST). The results demonstrated the presence of polyphenols, mainly flavonoids and tannins. In addition, were observed an increase in metabolism when TCM and OST cells were incubated with all extracts of L. candicans. Based on this, L. candicans in these tumor types should be careful use, and that in vivo studies should be performed to prove the true effects of this plant.