Diversity

The genus Schizothorax comprises an important group of freshwater fishes in Xinjiang (China); however, detailed information on their skeletal anatomy remains limited. In this study, we combined micro-computed tomography (micro-CT) and traditional skeletal preparations to examine and compare the osteological characteristics of three representative Schizothorax species: Schizothorax biddulphi, Schizothorax eurystomus, and Schizothorax curvifrons. Distinct variations were observed in several skeletal structures, including the cranium, pharyngeal teeth, fin-supporting elements, and vertebrae. Among the three species, S. biddulphi and S. eurystomus showed generally similar skeletal architectures, whereas S. curvifrons exhibited more pronounced osteological differences. These findings provide new comparative osteological data for Schizothorax species and offer a morphological reference for future studies on the taxonomy, systematics, and conservation of these freshwater fishes. Full article

The Klamath-Siskiyou Ecoregion (KSE) of southwest Oregon–northern California, USA, has globally exceptional biodiversity but is experiencing mounting pressures from climate change and land uses. We conducted an ecoregional conservation assessment of the KSE and the Siskiyou Crest subregion (SCS), a proposed climate refugium within the KSE. We integrated protected area priorities based on established conservation targets with climate change planning and fire risk reduction for communities. Both areas contained very low levels (<30%) of protection (GAP status 1, 2) for nearly all land cover types (n = 17), including serpentine substrates where endemic plants are highly concentrated, older forests with potential refugia properties, and habitat for Northern Spotted Owl (Strix occidentalis caurina) and Pacific fisher (Pekania pennanti). At the ecoregional scale, high-severity fire levels were proportionately similar across GAP land-use status (“managed” vs. protected). However, high-severity fire was lowest for protected areas at the subregional scale, reflective of potential refugium properties. Most fuel treatments by federal agencies were >1 km from nearest structures, far removed from effective community fire protection in both locales. The relatively higher-elevation SCS is projected to maintain refugia properties (cooler, wetter) for longer periods than the KSE; however, that function may dissipate toward the end of the century and under a higher emissions scenario. We recommend increased protections of potential refugia combined with fire risk reduction of the built environment to more effectively maintain unique biota and prepare communities for increased likelihood of wildfire spillover events. Full article

A decade ago, several publications summarized the state of knowledge on Colombia’s non-marine turtle species, and in 2015, the Colombian Red Book of Reptiles assessed their national conservation status, yielding information to guide research and conservation priorities in this biodiverse country. However, a recent initiative has produced or updated the global extinction risk assessments of Latin American non-marine turtle species. We summarize the current state of knowledge on Colombian populations of these species and propose new research and conservation priorities. The number of threatened turtle species in Colombia and the magnitude of the threats they face are greater than previously thought. Despite advances in research on the Colombian populations of these species, knowledge biases exist across species, with many important aspects of their life histories and population trends poorly understood. Given the speed of habitat loss and degradation, the current levels of exploitation, and the lack of enforcement of the legislation that protects them, we predict continued declines in population densities and distributions. We emphasize the need for more life-history studies and monitoring of population trends and threats to assign a more realistic category of national extinction risk and request the implementation of conservation legislation and the establishment of conservation programs. Full article

Assessing biodiversity within protected areas requires consideration of not only the extent of protection but also multiple dimensions of biodiversity, including species richness, composition, and turnover. This issue is particularly relevant to the Kunming–Montreal Global Biodiversity Framework Target 3, which emphasizes area-based conservation by protecting 30% of terrestrial areas by 2030. However, empirical case studies examining how plant biodiversity is associated with protection coverage at fine spatial scales within protected areas remain limited, particularly in East Asian temperate forests. We aimed to examine the relationships between grid-scale protection coverage and plant species richness, species composition, species turnover, and multisite species-sharing structures within the core zone of the Baekdudaegan Protected Area in Korea. Plant biodiversity was analyzed using 60 grid cells (each 1:25,000 topographic sheet units, ~100 km²) located within legally protected core zones with minimal human disturbance. Negative binomial regression, beta regression, non-metric multidimensional scaling, and ζ-diversity analyses were applied to evaluate relationships between protected area extent and biodiversity patterns. Core-zone area with greater protection coverage supported higher plant species; however, climate and topography were stronger drivers of species richness. Species turnover and community assembly patterns were not significantly associated with protection coverage. ζ-diversity analyses supported a power-law model across all area groups, indicating deterministic community assembly driven by environmental filtering. These findings suggest that protection coverage is positively associated with α-diversity but shows no clear association with qualitative aspects of biodiversity such as species turnover and community assembly. Although our correlational design does not allow causal inference, the results suggest that future conservation policy should incorporate habitat quality, environmental representativeness, and ecological connectivity alongside area expansion. Full article

Sargassum biomass has attracted increasing attention due to its massive accumulation along the Mexican Caribbean coast (Riviera Maya) and its potential role in carbon cycling. Although previous studies have reported calcium carbonate formation associated with Sargassum, the crystallographic nature of these biomineralized phases and the possible incorporation of Mg into the carbonate lattice remain poorly understood. In this study, carbonate phases associated with Sargassum collected from the Mexican Caribbean were investigated using X-ray diffraction (XRD), Rietveld refinement, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS), and transmission electron microscopy (TEM). Structural, morphological, and compositional analyses consistently revealed calcite as the dominant carbonate phase, exhibiting lattice modifications associated with Mg incorporation. Rietveld refinement identified crystallographic changes consistent with Mg substitution within the calcite lattice, while complementary characterization confirmed Mg-bearing carbonate domains and local structural distortions characteristic of high-Mg calcite (HMC). The combined results provide strong evidence for the formation of HMC associated with Sargassum, demonstrating that Mg incorporation occurs within the carbonate structures of a non-calcifying brown macroalga, a process previously reported predominantly in calcifying organisms and calcareous algae. These findings expand the current understanding of biomineralization pathways in marine ecosystems and suggest that Sargassum can promote the transformation of dissolved inorganic carbon into carbonate minerals. The occurrence of HMC highlights the potential role of Sargassum as a natural bioremediator and a contributor to transient carbon fixation through carbonate formation, providing new insights into the role of brown macroalgae in carbonate production and carbon cycling. Full article

Biological invasions and environmental gradients are major drivers of biodiversity change in wetland ecosystems, but their associations on native plant diversity in Central Asian riverine wetlands remain poorly understood. We surveyed 158 wetland plant communities across 54 transects in the Ertix River Basin to examine how environmental gradients (elevation, mean annual temperature [MAT], and mean annual precipitation [MAP]) and non-native plant establishment jointly related to native plant importance values and alpha diversity indices. Non-native plants were classified according to invasion stage—non-naturalized, naturalized, and invasive—to elucidate how the associations between alien plants and native communities shift dynamically along the invasion continuum. Elevation emerged as the dominant predictor, explaining 82% (individual R² = 0.15) of the variance in native species richness and 63.37% (individual R² = 0.1) of the variance in the Shannon–Wiener diversity index, while MAT and MAP were not retained as significant predictors in the optimal models. Native plant importance values, richness, and diversity all increased with elevation. Unexpectedly, naturalized plant richness and abundance were positively associated with native diversity metrics, contrasting with the negative associations of all non-native categories (non-naturalized, naturalized, and invasive) on native importance values, partly reflecting the compositional nature of this metric. Our results reveal positive co-occurrence patterns between early-stage naturalized species and native species, but native dominance may eventually decline as invasion intensity increases. These findings highlight the importance of considering invasion stage when predicting wetland biodiversity responses to biological invasions under environmental heterogeneity. Full article

The rules of Bergmann and Rensch are among the macroecological patterns most frequently used to explain body size and sexual dimorphism variations throughout geographic gradients. While Bergmann’s rule predicts an increase in size in higher latitudes and cold regions, Rensch’s rule describes allometric patterns in the expression of sexual dimorphism between males and females. Widely distributed organisms whose growth relies on external resources, such as the hermit crabs that utilize gastropod shells, constitute particularly adequate systems to investigate these patterns. In this study, we evaluate the occurrences of these rules in populations of the hermit crab Clibanarius sclopetarius distributed along the Brazilian shore. The morphologic variation was analyzed through traditional and geometric morphometry, integrating information regarding shape and size as well as comparing males and females from different populations. Regression models and multivariate analyses were employed in order to test associations between morphologic variables, latitude, and microhabitat. Although morphologic variations between populations and sexes have been detected, the patterns observed did not consistently follow the macroecological rules when considering latitude alone. By contrast, differences between analyzed microhabitats, mangrove forests, and rocky shores have been associated with distinct ecological contexts, which influence the expression of body size and sexual dimorphism. Full article

This study investigated long-term changes in zoobenthos in Lake Balkhash using data from 1975 to 2024. Lake Balkhash provides a suitable system for this analysis. Its hydrological regime is subject to fluctuations due to the combined use of its water for hydropower and irrigation. A total of 66 zoobenthic taxa were recorded. Boxplot analysis revealed substantial temporal variability in taxonomic richness over the study period. CONISS clustering identified temporal differences in zoobenthic taxonomic composition and distinguished different community states over time. However, the results should be interpreted with caution due to changes in sampling effort and improvements in taxonomic resolution over time, which may have influenced observed patterns in taxonomic richness. Water-level data for Lake Balkhash (1975–2022), representing the longest complete hydrological record available, were analyzed to assess relationships between water-level dynamics and zoobenthic taxonomic richness across two hydrological periods (≤1999 and ≥2000). Spearman correlation revealed a positive relationship between water level and taxonomic richness, which was slightly stronger with a one-year lag. However, the low explained variance suggests that additional environmental factors also influenced taxonomic richness. Full article

The Chihuahuan Desert Biome (CDB), the largest semi-arid region in North America, has undergone repeated climatic fluctuations during the Interglacial–Glacial Oscillation (IGO) of the last eight million years. We investigated biogeographic and evolutionary patterns of endemic cacti within the present-day Interglacial and the Last Glacial by examining 119 strict endemics, including 75 suitable for Species Distribution Modeling (SDM) and 44 microareal strict endemics, together representing 36.17% of the 329 species in the biome. Cacti probably originated in South America after substantial separation from Africa, with pollen fossils documenting their presence in Mexico by 51.6 Ma. Climatic reconstructions for each phase were developed using regional numerical and co-kriging methods following Sánchez-Santillán and García, complemented by paleoclimatic evidence from Scotese, Roy-Priyadarsi, Van Devender, and Betancourt. MAXENT SDMs and PANBIOTRACKS’ track-node analyses were applied to 3719 specimens representing 2015 localities to explore the colonization patterns and broad evolutionary trends. Combined suitability layers and panbiogeographic analyses revealed a predominant southeastern-to-northwestern colonization pattern, largely following the western flank of the Sierra Madre Oriental and intermontane valleys. The northern sectors were less diverse, more arid, and apparently colonized more recently, whereas the southern sectors concentrated much of the endemic richness and connectivity. The concordance among climatic suitability patterns, tracks, nodes, and the available phylogenetic evidence supports a major role of climatic oscillations in shaping the spatial and evolutionary history of endemic cacti throughout the CDB. Full article

The planthopper pests Geisha distinctissima and Ricanula fujianensis are major threats to tea plantations. Although insect endosymbionts are functionally important, their communities in these pests are poorly understood. This study, conducted in the representative tea-growing region of Guiyang in southwestern China, employed high-throughput sequencing to analyze the bacterial and fungal endosymbionts of both species. We found that bacterial communities were dominated by Proteobacteria and Firmicutes, with core genera such as Enterobacter and Rickettsia showing significant interspecific variation. Fungal communities were primarily composed of Ascomycota and Basidiomycota, and key genera like Fusarium exhibited host-specific patterns. Most notably, we discovered an intriguing pattern: bacterial communities differed in structure but showed conserved predicted functions, whereas fungal communities were structurally similar yet functionally divergent. This suggests that bacterial symbionts may underpin core physiological stability, while fungal symbionts could act as key drivers of host-specific adaptation. These results provide critical insights into planthopper–microbe interactions and establish a theoretical basis for developing targeted, microbiome-based pest management strategies. Full article

As a core component of terrestrial ecosystems, forests play an irreplaceable ecological role in carbon sequestration, biodiversity conservation, and global climate regulation. Home to key global forest belts including the Congo Basin, the African continent’s forest changes directly shape regional ecological balance and sustainable development while profoundly affecting global ecological security and climate dynamics. Based on the Shared Socioeconomic Pathways (SSPs), a unified narrative framework for global socioeconomic and environmental change scenarios, this study couples techniques such as the Future Land Use Simulation (FLUS) model, dynamic degree analysis, transition matrix, K-means clustering analysis, and patch fragmentation analysis. This work aims to answer two key questions: (1) What are the spatiotemporal characteristics and dominant drivers of African woodland changes under different SSPs? (2) How do spatial clustering and fragmentation patterns vary across scenarios? It systematically predicts and analyzes the spatiotemporal characteristics, driving mechanisms, and fragmentation change patterns of African woodlands in 2030, 2050, and 2070 under five scenarios (SSP1-SSP5) with 2020 as the baseline. These five official IPCC SSP frameworks represent five distinctly divergent socioeconomic development trajectories ranging from sustainable to fossil-fuel-driven development, which are the core differentiated scenarios recommended by IPCC; full inclusion facilitates systematic comparison of varied forest feedback features across Africa’s diversified national development backgrounds. The research results show that understory forests in the SSP5 (Fossil Fuel-dominated Development) scenario exhibit a stable growth trend, with the total area transferred in significantly exceeding the area transferred out from 2020 to 2070, resulting in a net increase of 143,513 km². This growth occurs because high-income economies under this scenario invest heavily in ecological restoration and forest protection, offsetting carbon-intensive development impacts. The core forest density continues to increase and is distributed in contiguous areas; the SSP4 (uneven development) scenario regarding forest degradation is the most severe, with the dynamic rate expected to drop to −0.05% between 2050 and 2070, and a net transfer of −265,581 km². Forest fragmentation is highest, and the core density area is gradually shrinking. Cluster analysis shows that forest area remains relatively stable in most African countries, with stable countries accounting for as much as 95.49% under scenario SSP5. Regions with woodland expansion are mainly distributed in North Africa and localized parts of Southern Africa. After refinement using independent tree-density evidence, woodland expansion in South Africa is shown to be more limited and spatially heterogeneous; these newly expanded woodlands are mostly artificial plantations and alien invasive tree stands rather than native natural woodlands, mainly occurring in eastern and southeastern areas rather than in arid western regions. The spatiotemporal transfer process exhibits significant periodic differentiation, with 2030–2050 being a critical transitional period for forest change, and the differentiation effect between scenarios intensifying. Fragmentation analysis indicates that scenario SSP3 (regional rivalry, with moderate population growth and weak policy constraints) has the best forest integration and the lowest degree of fragmentation, while scenario SSP4 is most strongly affected by human activities and has the highest risk of patch fragmentation. These findings can provide a scientific basis for African countries to formulate differentiated forest protection policies and optimize ecological restoration plans, while also offering theoretical insights for continental-scale forest ecological management. Full article

To establish non-destructive morphometric predictors of live body weight in the endangered freshwater pearl mussel (Margaritifera dahurica), 100 wild adult individuals were randomly selected. Four phenotypic parameters, including shell height (SH), shell length (SL), shell width (SW), and body weight (BW), were measured, and the interrelationships among these traits were statistically analyzed using correlation and path analyses. The results indicated that the phenotypic correlations among all traits of M. dahurica reached a highly significant level. Shell length exhibited the greatest direct effect on body weight, with a path coefficient of 0.718. The statistical associations of shell height and shell width with body weight were primarily mediated through indirect pathways via shell length. Shell length, shell width, and shell height were identified as the key morphometric predictors of body weight, yielding a total coefficient of determination of 0.879. Shell length possessed the highest comprehensive coefficient of determination (0.911), making it an ideal target trait for selective breeding. Using stepwise regression analysis, the optimal multiple linear regression equation of morphological traits on body weight was established as Log_BW = −0.814 + 2.482Log_SL + 0.522Log_SW. Rather than directly driving genetic breeding, these findings provide a grounded, non-destructive method for predicting live body mass, facilitating rapid biomass monitoring and founder broodstock assessment in M. dahurica. Full article

This study assessed the ecological status of the Aegean Sea coasts of Türkiye using the destructive Ecological Evaluation Index continuous (EEI-c) and non-destructive Benthic Ecological Assessment Rapid Index (BEARI) macroalgal indices within the framework of coastal ecological monitoring. A total of 25 coastal stations were investigated and macroalgal taxa were classified into sensitive Ecological Status Group I (ESG I) and Benthic Ecological Group I (BEG I) and tolerant–opportunistic Ecological Status Group II (ESG II) and Benthic Ecological Group II (BEG II), according to their ecological characteristics. Ecological quality status (EQS) was evaluated using EEI-c and BEARI, while Bray–Curtis similarity analysis and Principal Component Analysis (PCA) were applied to examine spatial patterns and relationships with environmental variables. The EEI-c assessment classified 19 stations as “high” and five stations as “good”, whereas only İzmir-Bostanlı exhibited “bad” ecological status. According to BEARI, five stations were classified as “high”, 17 as “good”, and Çandarlı, Güllük, and İzmir-Bostanlı as “moderate”, “poor”, and “bad”, respectively. A significant relationship was detected between EEI-c and BEARI values (R² = 0.71). In addition, Macroalgae-Land Use Simplified Index (MA-LUSI) values were negatively correlated with both EEI-c and BEARI, indicating the sensitivity of macroalgal indices to anthropogenic pressures. Overall, the results demonstrate that macroalgae-based indices provide reliable tools for ecological assessment and support multi-metric approaches in coastal monitoring programs. This study provides one of the first comparative evaluations of destructive (EEI-c) and non-destructive (BEARI) macroalgal indices in relation to MA-LUSI pressure assessment along the Turkish Aegean coasts. Full article

Naturally formed treefall gaps represent primary sources of environmental heterogeneity in tropical forests, yet their role in driving the components of beta diversity in specialized leaf-litter fauna remains poorly understood. We investigated the influence of natural treefall gaps on harvestmen (Arachnida: Opiliones) community structure and beta diversity partitioning in a well-preserved Atlantic Forest remnant in southern Bahia, Brazil. Using standardized nocturnal searches and leaf-litter sampling, we recorded 845 individuals across 23 species. Coverage-based rarefaction indicated higher estimated richness in gaps, although observed alpha diversity did not differ significantly among habitats. Community composition differed significantly along the gap–forest gradient, driven mainly by litter depth and microclimatic variation. Indicator species analysis identified Protimesius sp. (Stygnidae) as a robust gap-specialist. Beta diversity partitioning revealed that turnover accounted for 79.5% of total dissimilarity, while nestedness contributed 20.5%. Treefall gaps exhibited the highest internal beta diversity and species exclusivity, supporting their role as dynamic environmental filters that enhance regional diversity. Our findings highlight the ecological importance of natural disturbance and litter structure in maintaining biodiversity patterns in tropical forests. Full article

Rhodolith/maërl beds are biogenic habitats formed by free-living coralline algae, recognized for their ecological importance and global distribution. Along the Argentine coastline, the published literature lacks visual field documentation of rhodolith/maërl beds, despite historical reports of rhodolith-forming species. Here, we present visual records of a rhodolith/maërl bed in the Argentine Beagle Channel, associated with an extensive Macrocystis pyrifera kelp forest (~150 m from shore). Two perpendicular swimming transects allowed confirmation of a minimum spatial extent exceeding 40 × 40 m (>1600 m²). Underwater imagery reveals continuous rhodolith cover over unconsolidated sediments, highlighting a knowledge gap in the regional distribution of these habitats in southern South America. Full article

Colombia hosts 28 species of freshwater and terrestrial turtles, yet anthropogenic pressures such as illegal trafficking and urban expansion have intensified risks. In Cali, non-native turtles are frequently introduced into wetlands through pet abandonment and confiscations, creating novel assemblages in urban ecosystems. To examine this issue, ecological surveys were conducted in three urban wetlands during December 2024, complemented by enforcement records from the Wildlife Rescue Center (WRC) spanning 2015–2023 and reports from environmental authorities. Turtles were captured manually using natural baits placed in floating containers or along shoreline areas to attract individuals, then identified morphologically, measured for standard morphometric parameters, and released at the site of capture. WRC records were reviewed to assess species composition and causes of admission. Field sampling yielded 109 individuals representing four species (Trachemys callirostris, Podocnemis unifilis, Kinosternon leucostomum, Rhinoclemmys melanosterna). WRC records documented 2751 individuals across 11 species, with five taxa accounting for over 96% of admissions. Both datasets revealed a predominance of Trachemys callirostris. Morphometric data indicated multiple size classes, suggesting demographic heterogeneity within the turtle populations inhabiting the sampled wetlands. The overlap between confiscation records and wetland observations suggests potential links between illegal trade and species presence in urban wetlands, while the predominance of voluntary surrenders reflect the influence of enforcement activity and pet abandonment. Collectively, these findings demonstrate how urban wetlands facilitate the persistence of non-native turtles, reshaping species composition and underscoring the urgency of integrated strategies that combine enforcement, habitat management, veterinary protocols, and citizen education to safeguard native biodiversity. Full article

China harbors a diverse array of macrofungi, yet its fungal diversity remains inadequately documented, particularly in under-explored regions such as the temperate forests of the northeast and the subtropical highlands of the southwest. In this study, four agaric species are reported as new records for China based on morphological observations and multilocus phylogenetic analyses. Phylogenetic analyses of the internal transcribed spacer (ITS) and nuclear large subunit (nrLSU) ribosomal RNA gene regions confirmed their generic and species-level placements. Cortinarius infidus was collected from mixed coniferous and broadleaf forests in Liaoning Province, Pseudolaccaria fellea from Pine-dominated forests in Liaoning Province, Volvariella clavocystidiata from pine-dominated coniferous forests in Liaoning Province, and Gerhardtia borealis from mixed coniferous–broadleaf forests in Guizhou Province. Comprehensive macro and micromorphological descriptions, color photographs, line drawings, scanning electron micrographs, and comparisons with closely related taxa and original literature are provided to confirm these identifications. These findings contribute to a better understanding of the distribution patterns of these genera and expand the known fungal diversity of China. Full article

The black sea cucumber, Holothuria forskali, is an emerging target species for aquaculture; however, knowledge of its biology remains limited. Investigating its associated microbiota is a crucial step toward developing a controlled and sustainable aquaculture. In this study, the microbiota of three different body compartments of the host H. forskali—namely, the dorsal epidermis, the posterior intestinal content, and the coelomic fluid—were analysed using targeted metagenomics (V3-V4 rRNA 16S Metabarcoding). We compared host-associated communities with bacterial environmental communities across three periods in 2020 at two sites in south Brittany, totalling 309 analyses (36 environmental samples and 273 sea cucumber samples). The objective was to explore the diversity of the sea cucumber microbiota from the external to the internal regions of the animal. Thus, a total of 8695 OTUs were identified and classified into 52 bacterial phyla, 119 classes, and 45,596 orders. The results highlighted (1) anatomical compartmentalisation—with significantly different bacterial assemblages in terms of diversity, composition, and abundance across the three body regions—(2) host versus environment differences, and (3) temporal variations, as microbial community structures shifted significantly in winter compared to summer and autumn. This analysis identified specific taxa and families associated with each compartment with a potential role in host health. Results also showed relationships between the sea cucumber microbiota and their ambient environment. In fact, the presence of common bacterial taxa observed in the sediment and in the gastrointestinal microbiota supported the feeding behaviour of H. forskali. The sea cucumber microbiome thus appears to be compartmentalised “anatomically”, exhibiting a relatively low abundance of bacteria in the coelomic cavity, distinct from that of the microbial communities of seawater and sediments. This study highlighted the importance of the microbiota for the host and confirmed the existence of a core microbiota within H. forskali. Full article

Reflectance by yellow to red carotenoid-based plumages in birds with ultraviolet-sensitive (UVS) color vision typically shifts to redder (longer) wavelengths as carotenoid consumption (Diet_c) increases. This apparent asymmetric red-shift response implies an overall bias against conceivable shifts to bluer (shorter) wavelengths. However, recent studies among species of Piciformes–Coraciiformes (e.g., woodpeckers, barbets, toucans, bee-eaters, and allies) with violet-sensitive (VS) color vision discovered two kinds of blue shifts between the same plumage and dietary traits. Compared to UVS absolute red shifts (positive slopes at higher Diet_c), VS express absolute (negative slopes at higher Diet_c for yellow and orange plumages) or relative (zero slope for red plumages) blue shifts. These contrasting patterns for different color vision systems suggest that generalized symmetry concepts of opposite (plumage shift) patterns that maintain invariant (Diet_c, perception) processes can be abstracted from physical to biological systems, with positive versus negative responses formalized as “antisymmetries” and relative responses formalized as “broken symmetries”. A subset of VS “true woodpecker” (Picinae) species with known yellow and red plumage-carotenoid chemistries demonstrated similar blue shifts for the main reflectance bands and their independence from phylogeny, sex, and specimen collection year, thus providing key chemical details to further test generalized plumage symmetries. Juxtapositions were facilitated because both yellow and red plumages in true woodpeckers contained comparatively blue- and red-shifted carotenoid types. Despite this parallel, each plumage deployed chemical variations in radically different ways. Yellow plumage contained only chemically defined yellow carotenoids, including intrinsically more red-shifted natives (i.e., hydroxy-xanthophylls) widespread among birds through their diets, and intrinsically more blue-shifted picofulvins (i.e., 7,8-di- and tetra-hydro-carotenoids) probably characteristic of and metabolized by VS birds. Higher absolute and relative (to natives) picofulvin concentrations were significant predictors of absolute blue shifts in yellow plumage reflectance, and were significantly predicted by higher Diet_c. Transitivity implied Diet_c ⟶ native ⟶ picofulvin ⟶ reflectance, such that picofulvins caused absolute blue shifts at higher Diet_c, and natives caused absolute red shifts at lower Diet_c. Moreover, opposite trends for picofulvin and native concentrations in feathers were consistent with the proposed endogenous synthesis of picofulvins from natives. Yellow plumages comprised mainly of picofulvins at very low (from very low Diet_c from ants and termites) or high (from very high Diet_c from fruits) concentrations were especially distinctive for some of these and other interrelationships, suggesting some heterogeneity in yellow pigmentation strategies from dietary idiosyncrasies. Red plumages contained only relatively low concentrations of yellow dietary natives (hydroxy-xanthophylls), but varied widely in the concentration of metabolites of comparatively intermediate (4-oxo-keto-carotenoids) or extreme (4,4′-oxo-keto-carotenoids) redness. However, different red chemistries lacked any corresponding significant relationships with variations in reflectance or Diet_c. Variations in reflectance based on chemical compositions were more visible to humans for yellow than red plumage types, setting minimum salience levels for the more discriminating diurnal avian color visions. Therefore, VS yellow plumage chemistries that emphasize deposition of easily obtained (cheaper) dietary natives at low Diet_c, and of more deliberately synthesized (costly) picofulvin metabolites at higher Diet_c were consistent with several forms of honest signaling in UVS from resource limitations based on Diet_c, including through potential costs and benefits and their trade-offs. Conversely, the diverse chemical compositions and costs of red plumages of similar physical reflectance properties, and evidence that intrinsically orange carotenoids intermediate between red and yellow ones were actively excluded from plumage, suggested that true woodpecker reds were under selection for a convergent appearance. In light of true woodpecker biology, sensory bias, and social and aposematic mimicry are likely mechanisms promoting resemblance. These results extend to the chemical level earlier interpretations of opposite shift patterns as antisymmetries of invariant processes and relative shift patterns as broken symmetries of altered processes for VS vis-à-vis UVS carotenoid-based systems. Full article