Search Results (298)

Land-use type acts as a key anthropogenic factor shaping the diversity of pollinator communities. Different habitats indirectly alter pollinator species richness, abundance and community structure by regulating vegetation coverage and the abundance of host and nectar plants. To clarify the mechanisms underlying habitat effects on pollinator assemblages, we conducted transect surveys to investigate pollinator communities across three typical habitats (forest, cropland and urban area) in Nanchong City. Our results revealed that pollinator alpha diversity was significantly higher in forests than in croplands and urban areas, with urban habitats harboring the lowest species diversity. Vegetation coverage and nectar plant richness were identified as the primary environmental drivers of pollinator diversity. The plant–pollinator interaction network exhibited pronounced seasonal dynamics: spring networks displayed a distinct nested architecture dominated by generalized mutualistic interactions; networks shifted gradually from generalized to specialized links in early summer; and only a small number of specialist pollinators persisted in late summer to early autumn. Accordingly, retaining wild flowering herbs adjacent to pollinator-dependent crops and conserving autumn- and winter-blooming plant species can sustain continuous floral food resources for pollinators, promote pollinator richness, stabilize pollinator communities, and enhance the ecosystem service of pollination. Full article

Citizen science has extended the spatial and temporal scope of biodiversity data, yet questions remain regarding how these data can elucidate ecological interaction networks. Plant–pollinator networks are a comprehensive framework for assessing community structure, specialization, and resilience, but they are sensitive to sampling methodology and network composition. Here, we analyzed ten years of citizen science observations to characterize plant–pollinator network structure across four major insect orders, including Hymenoptera, Lepidoptera, Diptera, and Coleoptera. Key network metrics, including connectance, nestedness, linkage density, interaction evenness, specialization (H₂′), and modularity, were calculated to analyze network structure, including potential biases in the representation of specialist taxa (d′). To compare citizen science with standardized field observations, an Anthophila-only subset of the citizen science dataset was compared at the genus level with a traditionally sampled bee–flower network. Citizen science-based networks captured measurable specialization and connectance across four insect orders, exhibited significant spatial structure, and revealed that retained genera had significantly higher observed specialization than genera excluded by rare-taxon filtering, although the effect size was small. Within the Anthophila-only comparison, citizen science networks consistently exhibited higher linkage density and interaction evenness, whereas differences in connectance, nestedness, specialization, and modularity depended on whether complete, rarefied, or shared-genus networks were evaluated. These results indicate that inferred plant–pollinator network structure differed between sampling regimes and was sensitive to interaction count, taxonomic breadth, network dimensions, and spatial and temporal coverage. Citizen science captured broader spatial and taxonomic variation across a larger, temporally expansive dataset, whereas traditional sampling provided a more standardized snapshot of local bee–flower interaction structure. Full article

Camellia gauchowensis is widely distributed in South China. Field observations indicate that it produces abundant flowers but yields relatively few fruits under natural conditions. Understanding the intrinsic and extrinsic drivers of this low fruit output is essential both for revealing adaptive strategies in oil-tea camellia and informing cultivation improvement. In this study, we comprehensively investigated the flowering phenology, floral traits, pollen traits, pollinator activity, and breeding-system characteristics of C. gauchowensis. The results showed that C. gauchowensis produces perfect flowers but suffers from a narrow effective pollination window during its late-autumn-to-winter flowering period. Stomium-cell contaminants mixed with pollen grains may contribute to its poor pollen germination capacity. Cytochemical staining (TTC and FDA) significantly overestimated viability compared to in vitro germination results, and thus could not serve as a reliable substitute for functional pollen assessment. Both the outcrossing index and the pollen–ovule ratio indicated that C. gauchowensis exhibits a reproductive tendency toward outcrossing, with its sexual reproduction largely dependent on pollinators. Among the recorded floral visitors, Apis cerana represents the most promising pollinator candidate owing to its numerical dominance, frequent stigma contact, and superior cold-tolerance capacity. Our results reveal that reproductive success in C. gauchowensis is collectively constrained by multiple factors: a narrow effective pollination window, low pollen viability, winter-driven pollinator scarcity, and its reproductive tendency toward outcrossing. This study elucidates the coupled intrinsic–extrinsic mechanisms underlying low fruit output in this winter-flowering oil-tea camellia and provides theoretical underpinnings for pollination management and high-yield cultivation of this economically important woody crop. Full article

This review aims to synthesise existing knowledge on the efficacy, underlying mechanisms, and practical relevance of biostimulants within low-input agroecosystems, with particular emphasis on South Africa as a representative semi-arid, resource-constrained agricultural system, while highlighting broader implications for similar low-input agroecosystems in sub-Saharan Africa. This review paper reviews peer-reviewed and selected grey literature sources published between 1997 and 2026, retrieved through structured searches of Scopus, Web of Science, and Google Scholar using predefined keywords related to biostimulants, sustainable agriculture and South Africa. Across the literature, there is general agreement that biostimulants may indirectly support biodiversity through improved soil biological activity and reduced dependence on synthetic inputs, although direct field evidence remains limited. Methodologically, most studies are conducted under controlled or semi-controlled conditions, including greenhouses, growth chambers, and pot experiments. While these approaches allow for mechanistic understanding and precise variable control, they often fail to capture the complexity of field environments typical of low-input farming systems. This review synthesises peer-reviewed literature identified through structured searches of major databases utilising terms related to biostimulants, with an emphasis on studies conducted in both controlled environments and field settings. Evidence suggests that biostimulants can enhance plant physiological performance, improve stress tolerance, and contribute to more efficient resource use when integrated into appropriate management practices. However, their effectiveness is highly context-dependent, and they should not be considered substitutes for soil fertility management or sound agronomic practices. Future research, particularly in South Africa as a representative semi-arid and resource-constrained system, should prioritise field-based assessments and incorporate ecological indicators such as species abundance, pollinator visitation, and ecosystem resilience under biostimulant regimes to generate more robust and context-relevant evidence. Full article

While climate change is a significant pressure point for pollinators and honeybees, its long-term relationship with managed honeybee colonies and honey production remains unclear and context sensitive. This study, using FAOSTAT data from 1961 to 2024, examined the relationships between land surface temperature anomalies and the number of registered beehives, the constant-price honey production value, and the normalized honey production value per colony, both globally and specifically for 18 Mediterranean countries. To differentiate between long-term structural trends and short-term temperature relationships, correlation, regression, bootstrap confidence interval, temperature series sensitivity analysis, cross-correlation function, and normalized index analyses were used together. The study results show strong long-term co-movement between temperature anomalies and recorded beekeeping indicators at the global and Mediterranean scale in the level series; however, first-differenced (year-to-year) analyses show this association weakens substantially and, for Mediterranean honey production value, reverses sign, indicating that the level-series correlations are driven largely by common long-term trends. The relationship between temperature anomalies and beekeeping indicators shows a context-dependent structure among Mediterranean countries. The findings show that the increase in colony size does not always coincide with the increase in the constant-price honey production value per colony; in some cases, these two indicators can move in different directions. This indicates the need for an analytical decomposition of the dynamics of quantitative growth and economic production value per colony in the beekeeping sector. Full article

Honey bee colonies play a vital role in ecosystem stability and global food security. Together with bumble bees and other wild bee species, they form a diverse pollinator community that is particularly vulnerable to environmental pollution. Among stressors, environmental xenobiotics including heavy metals, metalloids, pesticides, polycyclic aromatic hydrocarbons, per- and polyfluoroalkyl substances, and emerging contaminants such as microplastics pose a growing concern due to their persistence, bioaccumulation potential and capacity to trigger oxidative stress and interact with pathogens, nutritional stress and climate-related extremes. The antioxidant defense system, encompassing enzymatic components (superoxide dismutase, catalase, glutathione-dependent enzymes and glutathione-S-transferase) and non-enzymatic antioxidants, represents a key protective mechanism, and its disruption leads to redox imbalance, immunosuppression, and behavioral alterations that can reduce honey bee colony vitality. This review synthesizes current knowledge on the sources, exposure pathways and toxicological effects of major environmental xenobiotics on the antioxidant defense systems of honey bees, with particular emphasis on oxidative-stress biomarkers for early detection of sublethal impairment in field and experimental settings. Where available, evidence from bumble bees and other wild bees is considered to place findings in a broader pollinator-health context and to highlight taxa-specific sensitivities. Work should now concentrate on a validated core panel of redox biomarkers, on chronic multi-stressor exposures that include PFAS and plastic particles, and on biomarker baselines for bumble bees and solitary bees tied to colony- or population-level endpoints. Full article

Breeding programs often adopt technologies before identifying the process that most limits genetic progress. This narrative review presents a bottleneck-first framework for annual self-pollinated crop breeding. It separates the diagnosis of a deficient pipeline domain from assessment of whether a specific intervention is actionable under uncertainty, capacity, and diversity constraints. Five domains are considered: usable variation, information for selection, biological progression and fixation, multi-environment validation, and delivery. Mandatory product gates and dependencies among domains determine priority. An intervention is actionable only when its lower uncertainty bound meets a predeclared minimum useful effect, downstream resources can absorb the added output, and diversity safeguards remain within declared limits. Three published cases provide retrospective stress tests: wheat high-throughput phenotyping, wheat pre-breeding, and SUBMERGENCE1 rice. Five additional cases examine realized gain, rapid generation advance, perennial selection, autotetraploid prediction, and promoter editing. A worked cereal example shows how capacity and diversity gates can reverse a technology-first priority. The framework complements rather than replaces selection indices, optimal contribution methods, genomic prediction, and breeding-scheme simulation. Its contribution is a transparent sequence for diagnosis, intervention testing, prioritization, and re-diagnosis. A prospective comparison with current breeding practice is still required. Full article

Macadamia (Macadamia spp.) is an economically important nut crop whose severe recalcitrance to genetic transformation substantially hinders progress in functional genomics and molecular breeding. To overcome this critical technical bottleneck, this study established a highly efficient and broadly applicable in planta hairy root genetic transformation system with integrated visual screening. This system utilizes an Agrobacterium rhizogenes-mediated transformation method, employing multiple visual reporter gene systems (DsRed2, eGFP, RUBY, and AtPAP2) to achieve antibiotic-independent and non-destructive screening of transgenic roots. Notably, the system innovatively incorporates the air layering (marcotting) technique to extend in planta genetic transformation to branches of mature trees in the field. By circumventing the stringent sterile conditions required for conventional in vitro tissue culture, this approach achieves a largely genotype-independent transformation across open-pollinated seedlings with diverse genetic backgrounds (A4, GR1, HAES900, and O.C.). The transgenic hairy root induction frequencies ranged from 39.25% to 47.38%, although the GR1 genotype exhibited a notable developmental stage-dependent decline in transformation efficiency. Furthermore, transgenic hairy roots were successfully induced on mature tree branches, with a maximum induction rate of 28.2%. Gene expression analyses confirmed the stable, high-level expression of the target transgenes in all the transgenic hairy root lines. This in planta transformation system provides a reliable in vivo experimental platform for the rapid functional validation of candidate genes and the investigation of root biology in Macadamia. Moreover, it establishes a novel strategy for plant regeneration via root-to-shoot organogenesis, offering a promising avenue for the genetic improvement of recalcitrant woody plants. Full article

To cope with severe seasonal changes in climate and food availability, colonies of Apis mellifera L. generate two distinct worker phenotypes during winter and summer. The aim of this research was to evaluate the effect of oral exposure to insecticides on the toxic susceptibility of winter and summer honeybee workers (Apis mellifera L.) under laboratory conditions. In this work, under all tested conditions and seasons, emamectin benzoate was the most toxic compound and used as the standard (Toxicity Index = 100) for comparison with other compounds. It had the lowest LC₅₀ (Lethal Concentration required to kill 50% of the tested honeybees) values, which decreased to 0.004 mg/L in winter bees after 48 h following oral exposure. Sulfoxaflor had moderate toxicity, and indoxacarb was the least toxic to honeybees. The results also revealed that the toxic effect was time-dependent, with lethal concentrations at 48 h significantly lower than those at 24 h. In addition, seasonal effects play a role; winter honeybees were, overall, more sensitive to the treatments than summer honeybees. Under the conditions of this study, it can be concluded that emamectin benzoate was the most toxic substance and indoxacarb the least toxic. Toxicity increased with exposure time. Winter honeybees showed greater sensitivity than summer honeybees. A field-relevant Hazard Quotient (HQ) analysis further indicated that indoxacarb, despite its lower acute toxicity, exhibited the narrowest margin relative to field-recommended spray concentrations, highlighting the value of incorporating field-relevant exposure metrics alongside LC₅₀-based rankings in pollinator risk assessment. It is worth clarifying that this narrower margin reflects indoxacarb’s higher field-recommended application rate relative to its LC₅₀, rather than a greater intrinsic toxicity than emamectin benzoate, and the two aspects of risk (intrinsic toxicity vs. use-rate-based field risk) should be interpreted separately. Full article

The nutritional composition and polyphenolic profile were determined in leaf and flowering shoots of burnet species (Sanguisorba officinalis, S. officinalis ‘Tanna’, and S. menziesii), with plant material further separated into leaves and stems. The results demonstrated that these herbs are valuable sources of dietary fiber, as well as being rich in protein and essential minerals. Depending on the morphological part, dietary fiber content ranged from 37.8 to 67.7 g/100 g, protein content from 5.3 to 19.5 g/100 g, and ash content from 3.8 to 9.9 g/100 g. Moreover, Sanguisorba species are particularly abundant in polyphenols (1–11% DM), with ellagitannins such as lambertianin C and sanguiin H-6 being the predominant constituents; in selected samples, they accounted for more than 90% of the total identified polyphenols. Due to their pleasant taste and aroma, and their dietary fiber, protein, and ellagitannin content, an attempt was made to evaluate their suitability as ingredients in food products. The results indicated that leaves are the most suitable for culinary applications into dishes such as soups and smoothies, whereas stems may serve as valuable raw material for dietary fiber- and phenolic-rich preparations. In conclusion, these findings support the promotion of edible herbs that are not only nutritious, palatable, and rich in ellagitannins, but also aesthetically valuable in garden settings and beneficial for pollinators. Full article

Knowledge of pollen viability, pollen longevity, and stigma receptivity in Zephyranthes remains limited despite their importance for successful hybridization. Therefore, this study evaluated these reproductive traits in four Zephyranthes species (Z. traubii, Z. candida, Z. grandiflora, and Z. citrina) and one cultivar, ‘Pim Chomphu’, to provide baseline reproductive information for controlled pollination. Pollen viability was evaluated using tetrazolium staining at different collection times and storage conditions, whereas stigma receptivity was assessed using 6% hydrogen peroxide (H₂O₂), with reproductive outcomes following controlled self-pollination evaluated at the corresponding time points. Tetrazolium-based pollen viability exhibited taxon-specific temporal patterns; however, viability was generally high at 11:00, corresponding to 1 day after anthesis (1 DAA) in Z. traubii and the day of anthesis (0 DAA) in the remaining taxa. The combined protocol of desiccation followed by storage at −5 °C or −20 °C maintained tetrazolium-based pollen viability for up to 120 days. Although all taxa showed positive H₂O₂-based stigma responses across the evaluated time points, reproductive outcomes following self-pollination differed markedly among taxa. Z. citrina set fruit at all pollination times, whereas Z. candida failed to set fruit. The remaining taxa showed variable fruit set and seed germination depending on pollination timing. These results indicate that positive H₂O₂-based stigma responses should be interpreted as biochemical indicators of potential stigma receptivity and considered together with subsequent reproductive outcomes. These findings provide baseline reproductive information to support pollen management and controlled pollination in Zephyranthes. Full article

The effective pollination period (EPP) is a key factor determining fruit set in sweet cherry, as it depends on the overlap between pollen tube growth and ovule longevity. This study investigated the duration and components of the EPP in three autochthonous cultivars (‘Stonska’, ‘Gomilička’, and ‘Tugarka’) grown in the Mediterranean region of Croatia over two consecutive flowering seasons. The EPP was determined under field conditions using sequential hand pollinations, while stigma receptivity, pollen tube growth, and ovule viability were assessed by fluorescence microscopy. Significant genotypic and seasonal variation in EPP and fruit set was observed. ‘Stonska’ and ‘Gomilička’ exhibited extended EPPs (9 and 11 days) and moderate to high fruit set. In contrast, ‘Tugarka’ showed a considerably shorter EPP (4–5 days) and consistently low fruit set (<10%). Stigma receptivity and pollen tube growth were not limiting factors for fertilization. However, rapid ovule degeneration in ‘Tugarka’, particularly under elevated temperatures during flowering, reduced the overlap between pollen tube arrival and ovule viability. These results indicated that ovule longevity plays a major role in determining fruit set and EPP under Mediterranean conditions. The study highlights genotypic differences in temperature sensitivity and provides insight into the potential impact of rising spring temperatures on sweet cherry production. Full article

Brazilian campos rupestres are a global center of plant endemism, but they are increasingly threatened by climate change and human activities. In this context, Sincoraea, an endemic genus of the Espinhaço Mountain Range, provides an important model for understanding how reproductive traits influence species persistence. This study investigated the floral biology, reproductive systems, nectar dynamics, and floral visitors’ interactions of several Sincoraea species through fieldwork conducted from 2023 to 2025. Floral biology and pollination were analyzed in four species, while pollen and stigma traits were examined in eight species using light and scanning electron microscopy. The flowers had white tubular corollas, diurnal anthesis, and high pollen viability during anthesis. Nectar production peaked in the morning. All recorded pollinators were hummingbirds and all species were self-incompatible, except S. burle-marxii, which was partially self-compatible. The reproductive effectiveness index was 1.00 for all species, suggesting that natural pollination provided effective conspecific pollen transfer without evidence of pollen limitation. These findings highlight the strong dependence of Sincoraea on floral visitors and emphasize the importance of conserving plant–floral visitor networks in campos rupestres. These interactions are essential for maintaining genetic diversity and the long-term stability of ecosystems. Full article

Background/Objectives: Rice (Oryza sativa) is the staple food for over half the global population, and nitrogen availability is the primary limiting factor determining rice yield. As the rate-limiting enzyme in nitrogen assimilation and allocation, glutamate synthase (GOGAT) plays an irreplaceable role throughout the plant life cycle. The evolutionary history, natural genetic variation, and regulatory networks of the GOGAT family in rice source–sink tissues during grain filling remain largely elusive. Methods: Here, we combined comparative genomics, population genetics, transcriptomic and biochemical approaches to systematically characterize the GOGAT gene family. Genome-wide identification was performed across 12 angiosperm species, followed by haplotype analysis using resequencing data from ~2000 rice accessions. Transcriptomic, enzymatic activity and metabolite content determination were integrated to investigate their responses to three nitrogen gradient treatments in source (roots, flag leaves) and sink (developing embryos) tissues. Results: A total of 48 GOGAT genes were identified, clustered into two ancient subfamilies (GLU/GLT), with a Poaceae-specific duplication event generating GLT1 and GLT2 subgroups. Specifically, three rice GOGAT genes exhibited distinct domestication signatures: Fd-GOGAT showed strong indica-japonica subspecific differentiation, while NADH-GOGAT2 harbored tropical japonica-specific haplotypes. Furthermore, tissue-specific and developmental stage-dependent nitrogen response patterns were revealed, identifying 5 days after pollination as the critical metabolic switch point. OsGOGAT promoters are enriched with light-, ABA- and stress-responsive cis-elements, suggesting coordinated hormonal and environmental regulation. Conclusions: This study provides comprehensive insights into the functional divergence of the plant GOGAT gene family and coordinated strategies that rice employs under exogenous nitrogen stress, and identifies elite haplotypes for nitrogen-efficient rice breeding. Full article

Honey bees (Apis mellifera) are key pollinators in agricultural ecosystems that face increasing pressure from pathogens and environmental change. However, how these environmental factors interact remains incompletely understood. To assess associations between climate, landscape composition, and pathogen occurrence in real agroecosystems, we monitored honey bee colonies across 30 apiaries in southern Italy over two years, in summer and autumn. Molecular screening revealed widespread multi-pathogen exposure, with two viruses, Black Queen Cell Virus (BQCV) and Deformed Wing Virus (DWV), and gut trypanosomatid parasite (Lotmaria passim) being the most frequently detected. In contrast, Nosema ceranae, along with Bee Macula-like Virus (BeeMLV) and Acute Bee Paralysis Virus (ABPV), occurred at lower but still notable frequencies. Infections were generally more frequent in adult foragers than in in-hive bees and larvae, and overall pathogen occurrence tended to be higher in summer than in autumn. Higher humidity was associated with higher overall pathogen occurrence and coinfection levels, whereas higher temperature showed a weaker association with these outcomes. Associations between landscape composition and pathogen occurrence differed across pathogens: a higher proportion of semi-natural habitats was associated with lower viral occurrence, particularly BQCV and DWV; however, N. ceranae was more frequently detected under the same landscape conditions. In contrast, L. passim showed context-dependent responses, with landscape effects emerging only through interactions with humidity and temperature. Pathogen coinfections were more occurrent under warm, humid conditions, although this pattern was partially buffered in landscapes richer in semi-natural habitats. Together, these results indicate that, within the studied apiaries, honey bee pathogen occurrence was associated with climate, season, and land use. These findings suggest that environmental context should be considered when interpreting honey bee health monitoring data in heterogeneous agricultural landscapes, with potential implications for apiary management. Full article