Search Results (785)

Toxoptera aurantii is a globally distributed piercing-sucking pest that severely threatens tea production. While the direct damage caused by aphid feeding is well documented, the systemic effects of infestation on plant-associated and soil microbial communities remain poorly understood. Here, we employed full-length 16S rRNA gene sequencing and untargeted metabolomics to investigate the influence of T. aurantii infestation on the microbiota of tea plants (Camellia sinensis) and rhizosphere soil across four sample compartments: aphid bodies, healthy leaves, aphid-infested leaves, and root-zone soil. Our results revealed pronounced niche-specific microbial assembly patterns. The aphid microbiome exhibited the lowest diversity and was dominated by obligate endosymbionts, including Buchnera aphidicola and the secondary symbiont Serratia symbiotica. Soil harbored the highest microbial diversity with a balanced phylum-level structure. Aphid infestation significantly reduced phyllosphere microbial diversity (Shannon index) and shifted community composition, with a decline in a sequence putatively assigned to Methylobacterium brachiatum and a modest increase in a taxon assigned to the opportunistic plant pathogen OTU assigned to Dickeya chrysanthemi. This pattern suggests a hypothesis that aphid infestation may create conditions permissive for such opportunistic pathogens, although experimental validation is required. Concurrently, infestation was associated with profound metabolic reprograming in tea leaves, including upregulation of defense-related flavonoids and terpenoids and downregulation of several primary metabolites. Notably, the phyllosphere of infested leaves showed reduced microbial diversity and an increased relative abundance of a 16S rRNA sequence assigned to Dickeya chrysanthemi, while certain plant-derived antimicrobial metabolites were decreased. These patterns suggest a possible association between aphid infestation, altered antimicrobial metabolite profiles and increased relative abundance of Dickeya-assigned sequences. These findings demonstrate that T. aurantii infestation triggers a systemic response in the aboveground compartments (aphid and leaf), while the soil compartment maintains a distinct and highly diverse microbial community that serves as a potential reservoir. The study characterizes microbial communities across these three compartments without inferring infestation-driven soil remodeling. This study advances our understanding of tripartite interactions in tea ecosystems and provides a basis for developing microbiome-based strategies for sustainable pest management. Full article

Silene zawadskii Herbich is an endemic species restricted to the South-Eastern Carpathians, being found in Romania and Ukraine. The species is rare and protected in the two countries. The root system is deep, to facilitate water absorption, the basal leaves, arranged in a rosette, are leathery and glabrous. The stem presents numerous multicellular, uniseriate non-glandular trichomes, only in the upper part; they become caducous at the base. The small size of the plant, correlated with the very narrow xylem vessels, represents a way of increasing the resistance to physiological drought and preventing embolism in drier periods. Another particular feature of this species is the presence of numerous large calcium oxalate crystals (druses), both in the stem and especially in the leaves. The flowers are adapted to entomophilous pollination, showing structural traits that facilitate interactions with alpine pollinators, particularly under conditions of reduced insect diversity at high altitudes. These anatomical traits reflect its ecological specialization, making it a valuable indicator for assessing edaphic–climatic niche specificity and the functional connectivity of high-altitude ecological networks. Full article

Lychee, an entomophilous fruit crop cultivated in tropical and subtropical regions, depends heavily on pollination services for optimal fruit yield and the economic sustainability of farmers. However, information on its pollinator interactions remains limited. This study was conducted over three flowering seasons to document the pollinator assemblage of lychee and examine variation in their activity under different physical conditions, including time of day, panicle height, and light–shade environments. Several insects (here, 47, including many butterflies, bees and flies) were recorded as flower visitors of lychee. The most effective pollinators were Apis cerana, Apis dorsata, Apis florea, Braunsapis mixta, and Tetragonula pagdeni. Pollinator abundance, species richness, diversity, and foraging traits (e.g., flower visitation rate and flower handling time) varied with daytime, inflorescence height, and light availability (light versus shade). Greater abundance, richness, and diversity were documented between 8:00 and 12:00 h, at mid-canopy height (2–6 m), and on well-lit inflorescences. Flower visitation rate was higher under these conditions, whereas flower handling time was lower. This study uncovered the key pollinators of lychee and demonstrated that plant–pollinator interactions vary across different physical conditions. These findings may help to improve pollinator management and enhance pollination services in lychee cultivation. Full article

Artemisia campestris is a medicinal plant species endemic to Algeria, particularly abundant in the southern regions and the central Sahara. Its long-standing use in traditional medicine has recently gained scientific attention, prompting further investigation into its bioactive potential. This study focuses on the phytochemical composition and biological activity of its hydromethanolic extract, with a particular emphasis on its ability to inhibit neural enzymes associated with insect physiology with particular relevance to Aphis gossypii (Glover), a major polyphagous agricultural pest. Preliminary screening revealed a diverse array of secondary metabolites, including tannins (catechic and gallic), flavonoids, quinones, glycosides, terpenoids, saponins, coumarins, and alkaloids; however, anthocyanins were not detected. Quantitative analysis confirmed high concentrations of total phenolics (80.91 ± 1.58 mg GAE/g), flavonoids (60.45 ± 2.02 mg RE/g), phenolic acids (4.24 ± 0.38 mg CAE/g), and condensed tannins (2.26 ± 0.29 mg CE/g). Enzyme inhibition assays were performed using Ellman’s method, and IC₅₀ values were calculated by nonlinear regression analysis based on dose–response curves. The extract demonstrated significant in vitro inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), with IC₅₀ values of 13.79 ± 0.79 µg/mL and 8.34 ± 0.58 µg/mL, respectively. Molecular docking analyses further confirmed strong binding affinities of cyanidin-3-O-glucoside, malvidin-3-O-glucoside, and apigenin (−8.20 to −8.50 kcal/mol) with the AChE active site, stabilized by hydrogen bonding and π–π interactions with key residues. These results were benchmarked against galantamine, a reference inhibitor, which exhibited IC₅₀ values of 1.50 ± 0.12 µg/mL under the same conditions. Although galantamine showed superior potency, the relatively low IC₅₀ values of the A. campestris extract support its potential as a natural cholinesterase-inhibitory agent warranting further investigation. These findings suggest that A. campestris may represent a promising source of natural cholinesterase inhibitors with potential relevance for eco-friendly insect control. These in vitro and in silico findings provide a mechanistic rationale warranting future in vivo bioassay validation against A. gossypii and related agricultural pests. Full article

The increasing resistance of agricultural pests and disease-vectoring arthropods to synthetic pesticides underscores the urgent need for novel and sustainable biocidal agents. This study evaluates, for the first time, the insect antifeedant and ixodicidal activities of essential oils derived from ten Amazonian Piper species and their major constituents. Antifeedant effects were assessed against Spodoptera littoralis, Myzus persicae, and Rhopalosiphum padi, whereas ixodicidal activity was tested on Hyalomma lusitanicum. Additionally, the effects of these oils on the plant-parasitic nematode Meloidogyne javanica were investigated. Essential oils from Piper mituense (51.6% apiol) and P. sancti-felicis (76.1% apiol) exhibited the highest bioactivity, achieving more than 75% feeding inhibition across all insect species and 100% tick mortality. P. mituense consistently demonstrated greater potency, suggesting possible synergistic interactions among its minor constituents. Principal component analysis linked apiol-rich chemotypes with broad-spectrum activity. In contrast, oils rich in oxygenated caryophyllene derivatives, particularly those from P. casapiense, showed strong selective antifeedant effects against R. padi. Pure apiol displayed activity across all assays, whereas no nematicidal effects were observed. Molecular docking analyses supported these findings, indicating that apiol can interact with acetylcholinesterase in addition to its known effect on cytochrome P450 targets. Overall, these results identify complementary Piper chemotypes with promising potential as dual-purpose biopesticides for integrated pest management strategies. Full article

Globally, Trichogramma Westwood (Hymenoptera: Trichogrammatidae) is known as the most effective biological control agent due to its ability to parasitize insect pest eggs. However, identifying an appropriate host is vital for Trichogramma to prosper. Therefore, this study delves into the complex role of semiochemicals in shaping the host-seeking behavior of Trichogramma parasitoids, with a particular focus on their responses to both plant-derived and host-derived cues. The mechanism of semiochemical reception in Trichogramma wasps relies on a highly specialized, sensitive olfactory and gustatory system to locate host eggs and mates. Semiochemicals, which mediate ecological interactions, have been identified as pivotal in influencing the parasitic efficiency of Trichogramma species. Trichogramma’s host-seeking behavior is influenced not solely by ovipositional cues but also by the intrinsic physical attributes of Lepidopteran hosts, such as the scales on the wings and abdomen, which emit semiochemicals capable of eliciting positive chemotactic responses, thereby guiding parasitoids toward optimal sites for oviposition. Furthermore, the interplay between insect-derived and plant-derived chemical cues exhibits a synergistic effect, collectively enhancing the chemotactic attraction of Trichogramma, thereby fine-tuning its host-seeking behavior with greater precision and specificity. This study further underscores Trichogramma’s innate behavioral ability to discriminate between host eggs of varying developmental stages, facilitating the precise identification and selection of the most suitable host for parasitization. Age and experience both make Trichogramma more selective of hosts, but younger parasitoids may take a broader approach to host selection due to their greater life expectancy. Furthermore, the removal of these cues affects their host localization and learning abilities. Associative learning enables Trichogramma to exhibit flexible behaviors, providing them with a selective advantage; allows them to explore various hosts; and reduces environmental uncertainty. Plant structure, host density, and host age are the key factors that significantly influence the foraging and parasitism of Trichogramma. The searching speed of this parasitoid is significantly influenced by temperature. Heat stress increases VOC emissions in plants such as potato via stomatal opening, reducing herbivore attraction and enhancing parasitoid recruitment. Furthermore, air pollution, including CO₂, O₃, and NOx, impairs parasitoid efficiency by disrupting volatile-mediated host location and reducing biological control performance. Trichogramma wasps are generally effective biological control agents, but their success depends on the species used, target pest, crop, release density, and field conditions. Overall, species such as T. ostriniae, T. japonicum, and T. leucaniae show the strongest performance in several crops by increasing parasitism, reducing pest damage, and improving yield. This study highlights the successful integration of semiochemical cues in pest management programs and the effective utilization of Trichogramma in conjunction with entomopathogenic bacteria to control Lepidopteran pests. This approach contributes to the development of more effective pest management strategies, thereby promoting agricultural sustainability. Full article

Plants can provide natural enemies with alternative food resources that enhance their performance in addition to prey consumption. Extrafloral nectaries attract beneficial insects by supplying nectar in exchange for pest suppression, although other arthropods may also benefit. This study aimed to characterize the extrafloral nectar composition of bottle gourd, Lagenaria siceraria (Molina) Standley (Cucurbitaceae), a host plant of Nesidiocoris tenuis Reuter (Hemiptera: Miridae), and to evaluate the effects of its carbohydrate profile on key biological parameters of this predator. Extrafloral nectar was chemically characterized for carbohydrate and amino acid composition, and laboratory bioassays were conducted to assess the effects of a sugar solution of the extrafloral nectar carbohydrate profile when provided with two factitious food sources, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) eggs and Artemia sp. (Anostraca: Artemiidae) cysts. Female egg production, nymphal development and food source consumption were evaluated. Chemical analysis revealed that bottle gourd extrafloral nectar consisted primarily of glucose, fructose, sucrose and melezitose, while serine was the dominant amino acid. Four essential amino acids were also detected. Sugar supplementation did not affect nymphal development rate but significantly reduced factitious food consumption. Significant differences in egg production were observed among feeding regimes. Sugar supplementation did not affect egg production when E. kuehniella eggs were provided, but significantly increased egg production when Artemia cysts were used as food source. These results indicate that extrafloral nectar carbohydrates can function as effective supplementary nutritional resources for N. tenuis, particularly when lower-quality factitious food sources are used. These findings enhance our understanding of plant–predator nutritional interactions and suggest that extrafloral nectar-derived components warrant further evaluation for incorporation into mass rearing protocols. Full article

The mosquito-associated virome may modulate host biology and influence vector competence, highlighting the importance of understanding its composition. Here, a metagenomic analysis was conducted to characterize the virome of the sea-rock pool mosquito Aedes mariae across sexes and developmental stages, together with water from its sea-rock pool breeding site in San Felice Circeo (Italy). A total of 51 viral taxa were identified, including viruses associated with bacteria and archaea (39%), plants, algae, fungi, and protists (35%), vertebrates (8%), and invertebrates (18%), including insect-specific viruses such as Mesoniviridae, Baculoviridae, Nudiviridae, Iridoviridae and Totiviridae. Twenty-five percent of the taxa were shared across samples, suggesting acquisition from breeding-site water and persistence across stages during development. Interestingly, the need for host genome filtering highlights the potential sequence similarity between viral and mosquito genomes, which may reflect the presence of endogenous viral elements or historical virus–host interactions. These findings represent the first characterization of the virome of Aedes mariae and highlight the role of aquatic breeding sites in shaping mosquito virome. Finally, we argue the importance of adequate sequencing depth and host genome filtering to capture the diversity of the mosquito virome. Full article

Bemisia tabaci (whitefly; Hemiptera: Aleyrodidae), a complex of morphologically similar but genetically distinct species, causes enormous agricultural damage worldwide. Farmers incur billions of dollars in losses each year from whiteflies, both through direct feeding damage and from the transmission of numerous plant viruses. Important crops that are heavily damaged by whiteflies include tomato, eggplant, cucumber, cotton, cucurbits, beans, and cassava. The global invasiveness and persistence of B. tabaci are largely attributed to its exceptional biological traits. Understanding these traits is essential for developing effective, long-term pest management strategies. This review describes in detail how the basic biology studies of B. tabaci provide a foundation for developing pest management strategies. Specifically, we discuss: (1) insights into the development of insecticide resistance can guide resistance management strategies; (2) knowledge of natural enemies supports the advancement of biological control approaches; and (3) understanding plant–insect interactions reveals molecular targets for innovative pest management solutions. We also examine emerging research trends and offer future perspectives on how ongoing studies may drive the development of next-generation control strategies (RNA interference, clustered regularly interspaced short palindromic repeats—CRISPR-associated protein 9 (CRISPR-Cas9), and horizontally transferred genes as targets). Full article

The melon fly, Zeugodacus cucurbitae (Coquillett), is a globally significant agricultural pest causing substantial economic losses. Odorant-binding proteins (OBPs) are critical of the insect olfactory system, yet their specific physiological functions in Z. cucurbitae remain largely uncharacterized. In this study, we functionally characterized ZcucOBP14 and investigated its putative involvement in host chemoreception and insecticide tolerance. Sequence alignment and phylogenetic analysis indicated that ZcucOBP14 belongs to the Minus-C OBP subfamily, and quantitative reverse transcription PCR (RT-qPCR) showed that it was predominantly expressed in both the head and abdomen. Fluorescence binding assays revealed that ZcucOBP14 exhibited broad binding affinity to 11 host plant volatiles, three sex pheromones, and two insecticides. Subsequent electroantennography (EAG) and behavioral bioassays identified isopulegol, 1-hexanol, linalool, and α-pinene as key ligands regulating the behavioral responses of Z. cucurbitae. RNA interference (RNAi)-mediated knockdown of ZcucOBP14 significantly reduced EAG responses to key ligands, eliminated behavioral preference, and increased insecticide-induced mortality by 20%. Molecular docking further identified that Tyr71, Ile67, Trp50, Val107, Phe116 and Leu70 were critical residues involved in ligand interactions. Collectively, these findings highlight the indispensable role of ZcucOBP14 in olfactory perception and its contribution to insecticide tolerance, laying a solid theoretical foundation for the development of novel behavior-modifying agents, attractants, and optimized integrated pest management (IPM) strategies against this pest. Full article

The xylem feeder Bathyllus albicinctus (Aphrophoridae: Cercopoidea: Hemiptera) has been identified as one of the most abundant and widely distributed cercopoid insects in Australia. This native Australian species might potentially vector Xylella fastidiosa, an exotic and deadly plant pathogen, if it were to arrive in Australia. Previous surveys indicated that B. albicinctus is associated with a wide range of plants, further elevating its impact as a potential disease vector. However, it is unknown if all the associated plants are equally viable hosts. Due to the variety of plant records and distribution across the southern half of Australia, it was expected that B. albicinctus would successfully feed and survive on a taxonomically diverse range of plants. In the present study, a small-scale no-choice feeding-controlled glasshouse experiment was completed where insect nymphs were supplied with plants that are economically significant and susceptible to X. fastidiosa. In this experiment, we monitored the maturation and longevity of B. albicinctus, specifically by comparing insect cohorts distinguished by nymph size, host species, or feeding season. This study documented important interactions of life-history factors for B. albicinctus, including suitability of host plant species among insect sex and season. This could indicate that the ability for B. albicinctus to spread X. fastidiosa may vary with host plant species and time of year. These findings provide a vital knowledge framework for future research and surveys to consider when implementing control efforts or tracking plant pathogens that may be spread by B. albicinctus. Full article

Most plant-based essential oil repellent products currently available on the market utilize a “green” approach based on the volatile properties of essential oils. In general, these essential oils contain terpenes, terpenoids, phenylpropanoids or benzenoids that can be used to either (1) eliminate a human’s scent through a process called odor masking, or (2) interfere with an insect’s ability to detect a person’s scent through interaction with both olfactory receptors and odorant binding proteins. Additionally, many of the essential oil blends that have been developed have been shown to exhibit antimicrobial and therapeutic properties. The primary drawback to using essential oil-based repellents is that their protection times vary widely, and typically last only a short period of time due to the volatile nature of the active ingredients, as well as differences in concentration and formulation among products. Encapsulation, nano-delivery systems, and rationally designed blend combinations are being proposed as potential methods to delay the release of the essential oil active ingredients, thus extending the duration of effectiveness of the repellent product. Since essential oils represent complex mixtures, there is a possibility that resistance to the repellent active ingredients could develop differently than it would for single-active agents. However, before such resistance can be assessed, the repellents must undergo extensive safety evaluations, along with standardized efficacy assessments against Environmental Protection Agency (EPA)-approved repellent products, and ultimately, field trials must be conducted in areas where the repellents will be used to prevent vector-borne diseases. In addition to conducting these evaluations, the repellents must comply with existing state and federal pesticide regulations. Full article

Insects, such as the Mediterranean fruit fly (Ceratitis capitata) and the armyworm (Mythimna unipuncta), and nematodes, including the root-knot nematode (Meloidogyne incognita) and the pine wood nematode (Bursaphelenchus xylophilus), are major agricultural pests. Essential oils (EOs) from aromatic plants are promising botanical pesticides due to their bioactivity. This study evaluated the in vitro effects of EOs from Origanum vulgare, Thymus vulgaris, Ocimum gratissimum, Mentha pulegium, and Cinnamomum cassia, and their main compounds (carvacrol, thymol, eugenol, pulegone, and trans-cinnamaldehyde, respectively), on acetylcholinesterase (AChE) and α- and β-glucosidases using crude enzyme extracts. All EOs inhibited AChE, with no significant effects on glucosidases. M. pulegium EO showed the strongest inhibition in C. capitata (IC₅₀ = 0.022 mg/mL) and B. xylophilus (IC₅₀ = 0.1209 mg/mL), while C. cassia EO was most effective against M. unipuncta (IC₅₀ = 0.0020 mg/mL) and M. incognita (IC₅₀ = 0.0197 mg/mL). In silico analysis revealed selective inhibition of insect AChE by EO-derived compounds, with insignificant effects on electric eel AChE, supporting species-specific interactions. These findings highlight EOs as selective, neurotargeting, and sustainable alternatives to synthetic pesticides. Full article

In plant–pre-dispersal seed predator interactions (e.g., flowerheads–flies), insect morphological differentiation is frequently driven by divergent host plants. However, wing morphological variation among flies associated with different flowerhead species has seldom been explored in natural alpine systems. In an alpine meadow of the Qinghai–Tibet Plateau, larvae of four host-associated morphological groups of Tephritis sp. cf. femoralis (1, 2, 3, 4) feed on four asteraceous species: Saussurea nigrescens (SN), Carduus nutans (CN), Leontopodium leontopodioides (LL), and Anaphalis lactea (AL). We examined the wing size and shape of these four groups using a landmark-based geometric morphometric approach. The host plants vary significantly in capitular diameter, dry weight, and depth. Within each host-associated group, female wing sizes (length, width and centroid size) were significantly larger than those of males. Wing size differed significantly among the four female and four male groups across host plants. Female ovipositor length varied in parallel with capitulum depth across the four host plants. Significant intersexual differences in wing shape were observed in SN, LL, and AL. Wing shape also varied distinctly among groups in both sexes across host plant capitula, enabling clear discrimination of host-associated groups. Linear discriminant analysis achieved high correct classification rates for both sexes, supporting clear morphological separation among host-associated groups. In conclusion, variations in wing size, wing shape and ovipositor length were associated with host traits. Overall, our study illustrates morphological differentiation correlated with host plants in flowerhead–fly pre-dispersal seed predator interactions in the alpine meadow system. Full article

Tomato yellow leaf curl virus (TYLCV) is a major plant pathogen that spreads worldwide through persistent circulative transmission by Bemisia tabaci. During transmission, TYLCV crosses several physiological barriers in the insect vector, evading immune defenses and altering host metabolic pathways to facilitate viral accumulation. Polyamines, essential for maintaining nucleic acid stability and promoting cellular processes, are known to play a critical role in viral accumulation. However, their role in TYLCV accumulation within B. tabaci is not well understood. Here, we demonstrate that TYLCV infection leads to significant alterations in polyamine levels in B. tabaci, with polyamine availability positively affecting viral DNA accumulation. Polyamine availability leads to higher viral loads and suppresses the expression of immune and MAPK signaling genes. These findings provide new insights into virus–vector and metabolic interactions underlying viral persistence in insect vectors. Full article