Plant Insect Research Articles

Mechanism of Exogenous Jasmonic Acid-Induced Resistance to Thrips palmi in Hemerocallis citrina Baroni Revealed by Combined Physiological, Biochemical and Transcriptomic Analyses

Jasmonic acid (JA) is a regulator of plant resistance to phytophagous insects, and exogenous JA treatment induces plant insect resistance. This study investigated the mechanism of exogenous JA-induced resistance of Hemerocallis citrina Baroni (daylily) to Thrips palmi at the biochemical and molecular levels. Daylily leaves sprayed with JA showed significantly higher levels of secondary metabolites—tannins, flavonoids, and total phenols, and activity of defense enzymes—peroxidase, phenylalanine ammonia lyase, polyphenol oxidase, and protease inhibitor (PI) than control leaves; the most significant effects were observed with 1 mmol L−1 JA. Owing to an improved defense system, significantly fewer T. palmi were present on the JA-treated plants than control plants. The JA-treated leaves had a smoother wax layer and fewer stomata, which was unfavorable for insect egg attachment. The differentially expressed genes (DEGs) were significantly enriched in insect resistance pathways such as lignin and wax biosynthesis, cell wall thickening, antioxidant enzyme synthesis, PI synthesis, secondary metabolite synthesis, and defense hormone signaling. A total of 466 DEGs were predicted to be transcription factors, mainly bHLH and WRKY family members. Weighted gene co-expression network analysis identified 13 key genes; TRINITY_DN16412_c0_g1 and TRINITY_DN6953_c0_g1 are associated with stomatal regulation and lipid barrier polymer synthesis, TRINITY_DN7582_c0_g1 and TRINITY_DN11770_c0_g1 regulate alkaloid synthesis, and TRINITY_DN7597_c1_g3 and TRINITY_DN1899_c0_g1 regulate salicylic acid and ethylene biosynthesis. These results indicate that JA treatment of daylily improved its resistance to T. palmi. These findings provide a scientific basis for the utilization of JA as an antagonist to control T. palmi in daylily.

Diffusive Phyllosphere Microbiome Potentially Regulates Harm and Defence Interactions Between Stephanitis nashi and Its Crabapple Host.

Pear lace bug (Stephanitis nashi) is a significant herbivorous pest, harbouring a diverse microbiome crucial for crabapple (Malus sp.) host adaptation. However, the mutual influence of S. nashi- and plant-associated microbiomes on plant responses to pest damage remains unclear. This study found that S. nashi damage significantly altered bacterial community structure and reduced bacterial evenness in the crabapple phyllosphere. Notably, bacterial diversity within S. nashi was significantly lower than that in the environment, potentially influenced by insect developmental stage, bacterial diffusion stage and endosymbiont species number and abundance. Extensive bacterial correlation and diffusion effect between S. nashi and adjacent plant environments were observed, evident in a gradual decrease in bacterial diversity and an increase in bacterial acquisition ratio from soil to phyllosphere to S. nashi. Correspondingly, S. nashi significantly impacted the metabolic response of crabapple leaves, altering pathways involved in vitamin, amino acid and lipid metabolism and so forth. Furthermore, association analysis linked these metabolic changes to phyllosphere bacterial alterations, emphasizing the important role of diffusive phyllosphere microbiome in regulating S. nashi-crabapple interactions. This study highlights bacterial diffusion effect between insect and plants and their potential role in regulating insect adaptability and plant defence responses, providing new insights into plant-insect-microbiome interactions.

Cicada nymph trace fossils from South American Maastrichtian paleosols

The Cretaceous was a pivotal Period in the evolution of major insect groups, including cicadas. Insect diversification led to an increased complexity in the paleosol ichnofabrics due to the emergence of chambers associated with reproductive and feeding behaviors. Therefore, any new record of trace fossils attributed to cicadas from the Cretaceous period represent a significant advancement in understanding the diversification of this group and the emergence of insect feeding chambers, throughout the geological record. This work describes the record of the ichnogenus Feoichnus attributed to feeding chambers of cicada nymphs (Hemiptera: Cicadidae) from Maastrichtian paleosols developed in floodplain deposits of The Marília Formation (Bauru Basin, Brazil). The described Feoichnus chambers are elongated, hemispherical, and upwardly concave, with a lining covering the inner surface of the wall. The inner surface exhibits thin, irregular ridges and grooves, likely associated with fine roots. Feoichnus occurs in association with Beaconites antarcticus and root traces found within the feeding chamber, it could be indicating the movement of the trace maker and the feeding chamber from one root to another. These characteristics indicate the xylem-feeding behavior of Feoichnus trace maker in accordance with extant cicada nymph ecology. The presence of Beaconites antarcticus associated with Feoichnus and rhizoliths probably represents the foraging behavior of cicada nymphs and the displacement of feeding chambers in well-drained, rooted soils. Therefore, the cicada nymph could be the trace maker of both traces representing feeding and locomotion behavior. This contribution expands the knowledge about plant–insect interactions and insect groups that compose the Cretaceous paleosols ichnofabrics from South America.

Navigational Signals for Insect and Slug Parasitic Nematodes: The Role of Ascorbate-Glutathione System and Volatiles Released by Insect-Damaged Sweet Pepper Roots.

This study of underground multitrophic communication, involving plant roots, insects, and parasitic nematodes, is an emerging field with significant implications for understanding plant-insect-nematode interactions. Our research investigated the impact of wireworm (Agriotes lineatus L. [Coleoptera: Elateridae]) infestations on the ascorbate-glutathione system in sweet pepper (Capsicum annuum L.) plants in order to study the potential role in root-exudate-mediated nematode chemotaxis. We observed that an A. lineatus infestation led to a decrease in leaf ascorbate levels and an increase in root ascorbate, with corresponding increases in the glutathione content in both roots and leaves. Additionally, a pigment analysis revealed increased carotenoid and chlorophyll levels and a shift towards a de-epoxidized state in the xanthophyll cycle. These changes suggest an individual and integrated regulatory function of photosynthetic pigments accompanied with redox modifications of the ascorbate-glutathione system that enhance plant defense. We also noted changes in the root volatile organic compound (VOC). Limonene, methyl salicylate, and benzyl salicylate decreased, whereas hexanal, neoisopulegol, nonanal, phenylethyl alcohol, m-di-tert-butylbenzene, and trans-β-ionone increased in the roots of attacked plants compared to the control group. Most notably, the VOC hexanal and amino acid exudate cysteine were tested for the chemotaxis assay. Nematode responses to chemoattractants were found to be species-specific, influenced by environmental conditions such as temperature. This study highlights the complexity of nematode chemotaxis and suggests that VOC-based biological control strategies must consider nematode foraging strategies and environmental factors. Future research should further explore these dynamics to optimize nematode management in agricultural systems.

Warming, nitrogen deposition, and provenance shift above-belowground insect interactions and host compensatory growth.

Above-belowground insect herbivore interactions and plant compensatory growth are crucial for reshaping the fitness of invasive plants, and it is likely that climate warming, nitrogen (N) deposition, and plant provenance influence this interaction and growth in a complex way. We performed an experiment with Solidago canadensis from home and introduced ranges, leaf-chewing Spodoptera litura, and root-feeding Protaetia brevitarsis under climate warming and N deposition, and addressed how these abiotic stressors and plant provenance jointly shaped the reciprocal effects between S. litura and P. brevitarsis and the compensatory growth of S. canadensis after herbivory. Under ambient conditions, S. litura and P. brevitarsis inhibited each other on the basis of growth; warming, N addition or warming plus N addition shifted or even reversed this competition depending on provenance. While the survival-based above-belowground interactions differed from growth-based ones, warming or warming plus N addition also shifted or even reversed the neutralism or amensalism detected under ambient conditions depending on provenance. S. canadensis from its home range was more tolerant of herbivory than from its introduced range under ambient conditions; warming, N addition or warming plus N addition decreased the plant compensatory growth of native S. canadensis, but increased that of invasive S. canadensis relative to ambient conditions. These findings suggest that climate warming and N deposition could enhance positive above-belowground insect interactions, increasing insect pressures on S. canadensis, and that plant provenance might be important in mediating climate change effects on insect interactions and host compensatory growth under plant invasions.

The Passo das Tropas outcrop complex and the Dicroidium Flora in southern Brazil

The Dicroidium flora, composed of different genera of fossil plants, has its first records dating back to the Permian, expanded significantly in diversity in the Triassic, occupying several regions of the Gondwanan territory, becoming a biostratigraphic landmark for the Triassic. In Brazil, this paleoflora is found in the sedimentary rocks of the Santa Maria region, state of Rio Grande do Sul, in locations close to the Passo das Tropas Creek, an informal type section of the Passo das Tropas Member, of the Santa Maria Formation. Pioneering studies on the subject in the region began in 1952, at the Passo das Tropas outcrop, which described the first records of the Dicroidium flora. Over the years, different outcrops were found in this region, which also revealed this paleoflora, such as: “Dom Antônio Reis” outcrop, “Zenir Aita” outcrop and “Espuma” outcrop, where several paleontological collections were carried out. In addition to plant fossils, fish scales and insect wings were recorded in these outcrops. However, these outcrops were totally or partially buried due to the urbanization process in the city of Santa Maria and its surroundings, making further studies impossible. This article presents a historical and stratigraphic review, compiling the work carried out in the last 70 years on the outcrops of the Passo das Tropas Member and presents a new fossil site, the outcrop called Estância dos Montes. A total of 125 specimens were recovered from the Estância dos Montes outcrop, belonging to Dicroidium odontopteroides, D. zuberi, D. lancifolium, Umkomasia sp., Pteruchus sp., Neocalamites sp. and seeds. The fossils presented in this work come from a paleontological rescue carried out at the Estância dos Montes outcrop and are currently deposited in the Paleontological Collection of the Laboratório de Estratigrafia e Paleobiologia of the Universidade Federal de Santa Maria. Not only the importance of preserving and protecting fossil sites and their contents is highlighted, but also the uniqueness of these fossils for the valorization of the regional heritage of Santa Maria and the global relevance of adding more data to compress the biota during the Gondwanan Triassic.

A Mini-Review on the Structural Characteristics and Anticancer Activity of Nagilactones

Abstract: Natural products provide abundant resources for the development of new drugs. Podocarpus nagi is an arbor of Podocarpus L'Hér. ex Persoon. Its fruits, leaves, and roots exhibit a broad spectrum of pharmacological activities (such as antitumor, plant growth regulation, termite killing, and insect larval toxicity), which have been used in Yao folk for a long history. Nagilactone is one of the key components discovered in Podocarpus nagi, which has a variety of structures and a broad spectrum of antitumor activities. In this mini-review, the structures and spectral characteristics, together with the antitumor activities and the structure-activity relationships of nagilactones, are summarized by searching the database in order to provide detailed references for researchers to elucidate and modify their structures.

Belowground diversity drives multifunctionality in grazing pastures on the eastern Tibetan Plateau

Livestock grazing can alter ecosystem structure, functions, and services across diverse biomes, with grazing intensity being a key factor affecting grassland function. Although the effects of grazing on plant and soil properties have been extensively studied, the effects of grazing intensity on biodiversity and ecosystem multifunctionality (EMF) remain largely unexplored. Therefore, this study addresses this gap using 28 indicator variables from a well-controlled yak grazing intensity experiment in alpine meadows on the eastern Tibetan Plateau. The results showed that aboveground diversity (calculated using plant species richness and insect diversity) exhibited a hump-shaped and significant response to increasing grazing intensity, multidiversity (whole-ecosystem biodiversity) and belowground diversity (calculated using nematode richness and microbial diversity) showed no significant response, and EMF significantly declined. Grazing decreased carbon and nitrogen cycling indices (calculated by carbon and nitrogen in plants and soils), but did not affect phosphorus cycling. Structural equation modelling indicated that EMF was directly affected by grazing intensity and belowground diversity (i.e., nematode and fungal diversity), rather than by multidiversity, aboveground diversity, and plant pathogens. Grazing-induced decreases in plant pathogens showed no direct or indirect effects on EMF but increased multidiversity and aboveground diversity. Overall, our results highlight the critical role of conserving belowground diversity in promoting and maintaining multifunctionality in grazing pastures on the Tibetan Plateau.

Heat wave impacts on crop‐pest dynamics are dependent upon insect ontogeny and plant resistance

AbstractHeat waves, brief periods of unusually high temperatures, are damaging to agroecosystems and are increasing in frequency and intensity due to climate change. Despite growing appreciation for the threat that heat waves pose to agricultural sustainability, we have a poor understanding of what determines their impact on agroecological interactions in the field. Here, we report the results of a field experiment that examined how heat waves and their timing interact with crop pest resistance to influence the interactions between potato (Solanum tuberosum) and its most damaging pest, the Colorado potato beetle (CPB; Leptinotarsa decemlineata). We used open‐top chambers and ceramic heaters to generate heat wave conditions in field plots with pest‐resistant and pest‐susceptible potato varieties at four CPB developmental stages. We then assessed CPB performance, leaf herbivory, and tuber yield. The neonate‐stage heat wave reduced larval survival by 10%, but the surviving larvae were 18% larger and developed 15% faster. However, these effects occurred only on the susceptible variety; both larval survival and growth were unaffected by the heat wave in the pest‐resistant variety. Moreover, the neonate‐stage heat wave reduced adult survival by 15%, suggesting negative carry‐over effects of early‐life heat exposure. Heat wave events after the neonate stage had no effects on CPB performance, crop damage, or tuber yield. Our results indicate that timing and pest resistance in crops are essential for understanding the impacts of extreme heat events on crop‐pest dynamics. Agroecological pest management in an increasingly variable and extreme climate will likely benefit from the development of strategies that account for the seasonal timing of potential heat events and from the continued use of crop varieties bred for pest resistance, which our results suggest may dampen the impacts of extreme temperatures on crop‐pest interactions.

Manipulation of juvenile hormone signaling by the fire blight pathogen Erwinia amylovora mediates fecundity enhancement of pear psylla.

In nature, plant pathogens often rely on insect vectors for transmission. Through long-term evolution, plant pathogens and insect vectors have established a mutually beneficial symbiotic relationship. Fire blight, caused by the Gram-negative bacterium Erwinia amylovora (Eam), poses a significant global threat to apple and pear production due to its rapid dissemination among host plants of the Rosaceae family. Despite evidence of E. amylovora transmission by various insects, the association between this pathogen and the pear psylla Cacopsylla chinensis, a common vector insect in pear orchards, remains unclear. Sampling investigations and qRT-PCR results revealed that C. chinensis, from 11 pear orchards severely affected by fire blight disease in Xinjiang of China, harbored varying levels of this pathogen. Eam-positive females exhibited significantly higher fecundity compared to Eam-negative individuals, displaying accelerated ovarian development and a notable increase in egg production. Further RNAi results revealed that juvenile hormone (JH) receptor methoprene-tolerant (CcMet) and a crucial downstream gene Krüppel-homologue 1 (CcKr-h1) mediated the fecundity improvement of C. chinensis induced by Eam. Additionally, miR-2b, which targets CcKr-h1, was identified as being involved in Eam-induced fecundity enhancement in C. chinensis. This study unveils, for the first time, that Eam colonize and amplify the fecundity of C. chinensis females. Host miR-2b targets CcKr-h1 of the JH signaling pathway to regulate the heightened fecundity of C. chinensis induced by Eam. These findings not only broaden our understanding of the interaction between plant pathogens and insect vectors, but also provide novel strategies for managing fire blight and pear psylla. © 2024 Society of Chemical Industry.

The feeding behavior of Diaphorina citri monitored by using an electrical penetration graph (DC-EPG) on citrus plants treated with Bacillus cereus and Bacillus velezensis

Diaphorina citri, an important pest and insect vector that can transmit the pathogenic bacteria Candidatus Liberibacter asiaticus, causing Huanglongbing disease, is one of many challenges in citrus agriculture. Integrated pest management by utilizing microorganisms is a wise and efficient alternative without damaging the environment. Utilization of Plant Growth Promoting Rhizobacteria (PGPR), such as Bacillus cereus and B. velezensis, is a potential strategy for the biological control of plant diseases or insect vectors. By inducing systemic resistance in plants, PGPR can enhance plant defense against diseases and insect pests while activating molecular and physiological changes in plants. This research aimed to determine the effect of B. cereus and B. velezensis on the plant growth and feeding behavior of D. citri. The height and volume of the plant canopy were observed periodically for 6 months, while the feeding behavior of D. citri was monitored using the Electrical Penetration Graph (DC-EPG). The results showed increased height and volume of the citrus plant canopy treated with B. cereus, indicating that B. cereus could act as a PGPR. The application of B. cereus and B. velezensis to citrus seedlings affected the feeding behavior of D. citri. D citri showed difficulty in penetrating the phloem tissue of citrus plants.

Use and impact of endophytic entomopathogenic fungi: Their potential in the context of agricultural sustainability

The use of entomopathogenic fungi (EF) as endophytes is an environmentally friendly alternative for sustainable food production, given that the current paradigm in crop protection is based on the use of organosynthetic pesticides, with more than two million tons per year worldwide. For these reasons, EF have the ability to live within plant tissues as endophytes acting as biopesticides. Under this scenario, this review analyzes and discusses the global status of the endophytic entomopathogenic fungi (EEF), their potential in plant protection against plant diseases and insect pests and as plant growth promoters. Successes and failures, and prospects for field application are examined. More than 7000 studies on EEF have been published, with important success cases. However, it is necessary to understand that the agricultural production is based on the use of external inputs, mainly pesticides. While progressive changes occur, it is fundamental to investigate the effect of these substances on the efficacy and persistence of EEF, without neglecting that the lack of knowledge of the effect of biotic and abiotic factors on EEF is an important cause of failures. Future studies should be focused on clarifying aspects such as: application strategies, endophytic persistence and transmission routes to improve the sustainability of agricultural production.

Histone deacetylase HDAC3 regulates ergosterol production for oxidative stress tolerance in the entomopathogenic and endophytic fungus Metarhizium robertsii.

Oxidative stress is encountered by fungi in almost all niches, resulting in fungal degeneration or even death. Fungal tolerance to oxidative stress has been extensively studied, but the current understanding of the mechanisms regulating oxidative stress tolerance in fungi remains limited. The entomopathogenic and endophytic fungus Metarhizium robertsii encounters oxidative stress when it infects insects and develops a symbiotic relationship with plants, and we found that host reactive oxygen species (ROSs) greatly limited fungal growth in both insects and plants. We identified a histone H3 deacetylase (HDAC3) that catalyzed the deacetylation of lysine 56 of histone H3. Deleting Hdac3 significantly reduced the tolerance of M. robertsii to oxidative stress from insects and plants, thereby decreasing fungal ability to colonize the insect hemocoel and plant roots. HDAC3 achieved this by regulating the expression of three genes in the ergosterol biosynthesis pathway, which includes the lanosterol synthase gene Las1. The deletion of Hdac3 or Las1 reduced the ergosterol content and impaired cell membrane integrity. This resulted in an increase in ROS accumulation in fungal cells that were thus more sensitive to oxidative stress. We further showed that HDAC3 regulated the expression of the three ergosterol biosynthesis genes in an indirect manner. Our work significantly advances insights into the epigenetic regulation of oxidative stress tolerance and the interactions between M. robertsii and its plant and insect hosts.IMPORTANCEOxidative stress is a common challenge encountered by fungi that have evolved sophisticated mechanisms underlying tolerance to this stress. Although fungal tolerance to oxidative stress has been extensively investigated, the current understanding of the mechanisms for fungi to regulate oxidative stress tolerance remains limited. In the model entomopathogenic and plant symbiotic fungus Metarhizium robertsii, we found that the histone H3 deacetylase HDAC3 regulates the production of ergosterol, an essential cell membrane component. This maintains the cell membrane integrity to resist the oxidative stress derived from the insect and plant hosts for successful infection of insects and development of symbiotic associates with plants. Our work provides significant insights into the regulation of oxidative stress tolerance in M. robertsii and its interactions with insects and plants.

Multiscale spatial analysis of two plant–insect interactions: effects of landscape, resource distribution, and other insects

ContextBiotic resource exploitation is a critical determinant of species’ distributions. However, quantifying resource exploitation patterns through space and time can be difficult, complicating their incorporation in spatial ecology studies. Therefore, understanding the local drivers of spatial patterns of resource exploitation may contribute to better large-scale species distribution models.ObjectivesWe investigated (1) how the resource exploitation patterns of two trophic interactions (plant–insect) are explained by insect behaviour, resource aggregation, and potential insect-insect interactions. We also analyzed how (2) resource patch size and (3) resource accessibility in a heterogeneous landscape affected host exploitation patterns.MethodsWe quantified nectar robbing by insects in the genus Bombus (bumblebees) and seed predation by Brachypterolus vestitus larvae (Antirrhinum beetle) on Antirrhinum majus L. (wild snapdragons) in the Pyrenees Mountains, Catalonia, Spain. We tested hypotheses about resource exploitation by integrating spatial analyses at multiple scales.ResultsBoth trophic interactions were aggregated, explained by the aggregation of their resource. At some scales, nectar robbing is more aggregated than the resource. Trophic interaction abundance is proportional to resource patch size, following the ideal free distribution model. Landscape features do not explain the locations exploited. Nectar robbing and seed predation occur together more often than expected.ConclusionsOur findings suggest that multiple biotic and ecological spatial factors may simultaneously affect resource exploitation at a local scale. These findings should be considered when developing agricultural projects, management plans and conservation policies.

Application of deep ensemble learning for palm disease detection in smart agriculture

Agriculture has notably become one of the fields experiencing intensive digital transformation. Leveraging state-of-the-art techniques in this domain has provided numerous advantages for agricultural activities. Deep learning (DL) algorithms have proven beneficial in addressing various agricultural challenges. This study presents a comprehensive investigation into applying DL models for palm disease detection and classification in the context of smart agriculture. The research aims to address the limitations observed in previous studies and improve the robustness and generalizability of the results. To achieve this, a two-stage optimization methodology is employed. First, transfer learning and fine-tuning techniques are applied using various pre-trained deep neural network models. The experiments show promising results, with all models achieving high accuracy rates during training and validation. Furthermore, their performance on unseen test data is also assessed to ensure practical applicability. The top-performing models are MobileNetV2 (92.48 %), ResNet (92.42 %), ResNetRS50 (92.30 %), and DenseNet121 (92.01 %). Second, a deep ensemble learning approach is applied to enhance the models' generalization capability further. The best-performing models with different criteria are combined using the ensemble technique, resulting in remarkable improvements in disease detection tasks. DELM1 emerges as the most successful ensemble model, achieving an ROC AUC Score of 99 %. This study demonstrates the effectiveness of deep ensemble learning models in palm disease detection and classification for smart agriculture applications. The findings contribute to advancing disease detection systems and emphasize the potential of ensemble learning. The study provides valuable insights for future research, guiding the application of DL techniques to address critical agricultural challenges and improve crop health monitoring systems. Another contribution is combining various plant diseases and insect pest classes using diverse datasets. A comprehensive classification system is achieved by considering different disease classes and stages within the white scale category, improving the model's robustness.

Diversity, Stability, and the Forecast Challenge in Forest Lepidopteran Predictive Ecology: Are Multi-Scale Plant–Insect Interactions the Key to Increased Forecast Precision?

I report on long-term patterns of outbreak cycling in four study systems across Canada and illustrate how forecasting in these systems is highly imprecise because of complexity in the cycling and a lack of spatial synchrony amongst sample locations. I describe how a range of bottom-up effects could be generating complexity in these otherwise periodic systems. (1) The spruce budworm in Québec exhibits aperiodic and asynchronous behavior at fast time-scales, and a slow modulation of cycle peak intensity that varies regionally. (2) The forest tent caterpillar across Canada exhibits eruptive spiking behavior that is aperiodic locally, and asynchronous amongst regions, yet aggregates to produce a pattern of periodic outbreaks. In Québec, forest tent caterpillar cycles differ in the aspen-dominated northwest versus the maple-dominated southeast, with opposing patterns of cycle intensity between the two regions. (3) In Alberta, forest tent caterpillar outbreak cycles resist synchronization across a forest landscape gradient, even at very fine spatial scales, resulting in a complex pattern of cycling that defies simple forecasting techniques. (4) In the Border Lakes region of Ontario and Minnesota, where the two insect species coexist in a mixedwood landscape of hardwood and conifers, outbreak cycle intensity in each species varies spatially and temporally in response to host forest landscape structure. Much attention has been given to the effect of top-down agents in driving synchronizable population cycles. However, foliage loss, tree death, and forest succession at stem, stand, and landscape scales affect larval and adult dispersal success, and may serve to override regulatory processes that cause otherwise top-down-driven periodic, synchronized, and predictable population oscillations to become aperiodic, asynchronous, and unpredictable. Incorporating bottom-up effects at multiple spatial and temporal scales may be the key to making significant improvements in forest insect outbreak forecasting.

Aspects of the ecology of Leporinus striatus Kner 1858 as a support for its conservation in a Federal Conservation Unit

This work describes aspects of the ecology and feeding of Leporinus striatus to fill the gap in information about the species in Brazilian rivers. The study area is in the Ipanema National Forest, Iperó/São Paulo, with the Ipanema River as the place where the specimens were collected in its middle and lower reaches. The size ranged from class 9.0 - 9.5 cm to class 11.5 - 12.0 cm, with females being found in all classes. Class 10 - 10.5 was the one with the highest relative frequency, with males being most abundant in the 9.5-10.0 cm length class and females in the 10-10.5 cm length class. The species' diet was composed of autochthonous species, with the most frequent items being insect fragments and plant material. Based on this information, the species was classified as omnivorous. Underwater observations made it possible to verify that the species is gregarious, inhabiting the water column between midwater and the bottom, preferring stretches with currents and rocky substrate. It performs foraging by leaning its body close to the substrate and biting food on solid surfaces. Small groups made up of at least six individuals shared the areas between rocks and branches. We conclude that, to guarantee the preservation of the species, it is crucial to recognize the significant role played by Conservation Units. However, given the aquatic nature of the species studied, its life cycle is intrinsically linked to stretches that extend beyond the limits of the UC. Additionally, the ecological analyses presented in this study reveal that the species relies on the preservation of a healthy river environment that transcends the boundaries of the conversational unit.

Integrated vegetation management within electrical transmission landscapes promotes floral resource and flower-visiting insect diversity.

Electrical transmission rights-of-way are ubiquitous and critical infrastructure across the landscape. Active vegetation management of these rights-of-way, a necessity to deliver electricity more safely, maintains these landscape features as stages of early successional habitat, a rarity in many regions, making these areas viable movement corridors for many taxa. The goals of this study were to (i) evaluate the effects of different electrical transmission landscape management practices on flowering plant and flower-visiting insect diversity parameters and (ii) generate conservation management inferences for these landscapes. In this study we tested the impact of three vegetation management levels across 18 electrical transmission sites. We evaluated the effects of treatment on bloom abundance and species richness as well as flower-visiting insect abundance and family richness. We identified 76541 flowers/inflorescences across 456 transects, including 188 species in 56 plant families. Additionally, we obtained data on 11361 flower-visitoring insects representing 33 families from 2376 pan trap sets. High vegetation management favored the reduction of coarse woody debris in the sites and harbored the highest level of abundance and richness of both floral resources and flower-visiting insects. We discuss that we can align social and ecological values of rights-of-way, ensuring their sustainability by applying regular and targeted integrated vegetation management. Thus, we can use rights-of-way landscapes not only as an effective management strategy for the delivery of essential human services, but also to provide conservation benefits for wild pollinators.

First Report of Impatiens Necrotic Spot Virus (INSV) Infecting Tomatoes in North Carolina.

Impatiens necrotic spot virus (INSV) (Orthotospovirus impatiensnecromaculae) is a virus in the Order Bunyavirales and Family Tospoviridae. The virus is vectored by several species of thrips and is a serious pathogen of ornamentals and lettuce in the United States (Hasegawa & Del Pozo-Valdivia 2023; Daughtrey, M. L., et al. 1997; Webster, C. G., et al. 2015). In January 2023, tomato plants (Solanum lycopersicum,'Big Dena') with viral symptoms of reduced vigor, wilting, necrotic spots on leaves, and sunken lesions on the stem were observed in one greenhouse in Guilford County, North Carolina (NC) (Figure 1A-C). Disease incidence was low (2%), with only three symptomatic plants in the single greenhouse. Affected plants also had signs of thrips feeding (dead thrips, frass, and feeding scars) present across the whole plant (Figure 1D). Samples were submitted to the NC State Plant Disease and Insect Clinic and tested positive for INSV, but negative for TSWV, using Agdia ImmunoStrips®. RNA was extracted from symptomatic leaf tissue using the IBI Total RNA Mini kit (Plant), and complementary DNA (cDNA) was generated using the ThermoFisher Verso cDNA synthesis kit. A reverse transcriptase (RT)-PCR with INSV nucleocapsid (N) primers (F:5'-ATGAACAAAGCAAAGATTACC-3' and R:5'- TTAAATAGAATCATTTTTCCC-3') was used to confirm INSV presence (Hassani-Mehraban et al. 2016). Full length N cDNA amplicon sequencing [GenBank No. PP658213] revealed 99.62% nucleotide identity to NCBI GenBank accessions KF926828 (orchid in California), MH453554.1 (hosta from NY), and MH453552.1 (foxglove from NY), all of which are INSV N sequences. The infected leaf samples were used to mechanically inoculate Emilia sonchifolia and tomato (cv.'Moneymaker') using standard virological methods. We successfully infected E. sonchifolia with INSV (confirmed with visual mosaic symptoms and positive INSV ImmunoStrip). However, mechanical inoculation of the tomato plants proved unsuccessful. Using the INSV infected E. sonchifolia leaves as an inoculum source, we generated a viruliferous Frankliniella occidentalis (Western flower thrips) cohort and challenged three week old tomatoes using thrips mediated inoculation (adapted from Aramburu et al. 2009 and Rotenberg et al., 2009). Twenty days post-inoculation, tomatoes with thrips feeding scars were symptomatic for INSV infection with chlorotic and necrotic spots, stunting, and reduced vigor. INSV infection of these tomato plants was verified with a positive INSV ImmunoStrip® result, two-step RT-PCR amplification of N, and Sanger sequencing of N. Samples from thrips-inoculated tomato plants did not test positive for TSWV. Sequence alignment showed that the recovered virus sequence was 99.85% identical to the original INSV sequence from the diagnostic sample (a single nucleotide difference). To the best of our knowledge, this is the first instance of INSV infecting tomato in NC production systems. Although TSWV is more common in vegetable production in NC (253 cases of TSWV compared to 1 case of INSV in vegetable crops based on NC State Plant Disease and Insect Clinic records since 2008), INSV incursion into tomato producing areas is concerning and should be closely monitored, especially at the transplant stage. This report also underscores the importance of using thrips vectors to transmit virus in screening for susceptibility to orthotospoviruses.

Densovirus infection facilitates plant-virus transmission by an aphid.

The interactions among plant viruses, insect vectors, and host plants have been well studied; however, the roles of insect viruses in this system have largely been neglected. We investigated the effects of MpnDV infection on aphid and PVY transmission using bioassays, RNA interference (RNAi), and GC-MS methods and green peach aphid (Myzus persicae (Sulzer)), potato virus Y (PVY), and densovirus (Myzus persicae nicotianae densovirus, MpnDV) as model systems. MpnDV increased the activities of its host, promoting population dispersal and leading to significant proliferation in tobacco plants by significantly enhancing the titer of the sesquiterpene (E)-β-farnesene (EβF) via up-regulation of expression levels of the MpFPPS1 gene. The proliferation and dispersal of MpnDV-positive individuals were faster than that of MpnDV-negative individuals in PVY-infected tobacco plants, which promoted the transmission of PVY. These results combined showed that an insect virus may facilitate the transmission of a plant virus by enhancing the locomotor activity and population proliferation of insect vectors. These findings provide novel opportunities for controlling insect vectors and plant viruses, which can be used in the development of novel management strategies.