Search Results (14)

Due to its abundance, bird cherry–oat aphid is the most important vector in Poland of the complex of viruses causing barley yellow dwarf virus (BYDV). These viruses infect all cereals. During the growing season, cereal plants are exposed to many species of agrophages, which can limit their growth, development and yield. As observed for many years, global warming contributes to changes in the development of many organisms. Aphids (Aphidoidea), which are among the most important pests of agricultural crops, respond very dynamically to these changes. Under favorable conditions, their populations can increase several-fold within a few days. The bird cherry–oat aphid (Rhopalosiphum padi L.) is a dioecious species that undergoes a seasonal host shift during its life cycle. Its primary hosts are trees and shrubs (Prunus padus L.), while secondary hosts include cereals and various grass species. R. padi feeds directly on bird cherry tree, reducing its ornamental value, and on cereals, where it contributes to yields losses. The species can also damage plants indirectly by transmitting harmful viruses. Indirect damage is generally more serious than direct feeding injury. Monitoring aphid flights with a Johnson suction trap (JST) is useful for plant protection, which enables early detection of their presence in the air and then on cereal crops. To provide early detection of R. padi migrations and to study the dynamics of abundance, flights were monitored in 2020–2024 with Johnson suction traps at two localities: Winna Góra (Greater Poland Province) and Sośnicowice (Silesia Province). The aim of the research conducted in 2020–2024 was to study the dynamics of the bird cherry–oat aphid (Rhopalosiphum padi L.) population in relation to meteorological conditions as recorded by a Johnson suction trap. Over five years of research, a total of 129,638 R. padi individuals were captured using a Johnson suction trap at two locations (60,426 in Winna Góra and 69,212 in Sośnicowice). In Winna Góra, the annual counts were as follows: 5766 in 2020, 6498 in 2021, 36,452 in 2022, 5598 in 2023, and 6112 in 2024. In Sośnicowice, the numbers were as follows: 6954 in 2020, 9159 in 2021, 49,120 in 2022, 3855 in 2023, and 124 in 2024. The year 2022 was particularly notable for the exceptionally high abundance of R. padi, especially in the autumn. Monitoring crops for the presence of pests is the basis of integrated plant protection. Climate change, modern cultivation technologies, and increasing restrictions on chemical control are the main factors contributing to the development and spread of aphids. Therefore, measures based on monitoring the level of threat and searching for control solutions are necessary. Full article

Telomeres are terminal regions of chromosomes that protect and stabilize chromosome structures. Telomeres are usually composed of specific DNA repeats (motifs) that are maintained by telomerase and a complex of specific proteins. Telomeric DNA sequences are generally highly conserved throughout the evolution of different groups of eukaryotes. The most common motif in insects is TTAGG, but it is not universal, including in the large order Hemiptera. In particular, several derived telomeric motifs were identified in this order by analyzing chromosome-level genome assemblies or by FISH screening the chromosomes of target species. Here, we analyzed chromosome-level genome assemblies of 16 species from three hemipteran suborders, including Sternorrhyncha (Coccoidea: Planococcus citri, Acanthococcus lagerstroemiae, and Trionymus diminutus; Aphidoidea: Tuberolachnus salignus, Metopolophium dirhodum, Rhopalosiphum padi, and Schizaphis graminum), Auhenorrhyncha (Cicadomorpha: Allygus modestus, Arthaldeus pascuellus, Aphrophora alni, Cicadella viridis, Empoasca decipiens, and Ribautiana ulmi), and Heteroptera (Gerromorpha: Gerris lacustris; Pentatomomorpha: Aradus depressus and A. truncatus). In addition, scaffold-level genome assemblies of three more species of Heteroptera (Gerromorpha: Gerris buenoi, Microvelia longipes, and Hermatobates lingyangjiaoensis) were examined. The presumably ancestral insect motif TTAGG was found at the ends of chromosomes of all species studied using chromosome-level genome assembly analysis, with four exceptions. In Aphrophora alni, we detected sequences of 4 bp repeats of TGAC, which were tentatively identified as a telomeric motif. In Gerris lacustris, from the basal true bug infraorder Gerromorpha, we found a 10 bp motif TTAGAGGTGG, previously unknown not only in Heteroptera or Hemiptera but also in Arthropoda in general. Blast screening of the scaffold-level assemblies showed that TTAGAGGTGG is also likely to be a telomeric motif in G. buenoi and Microvelia. longipes, while the results obtained for H. lingyangjiaoensis were inconclusive. In A. depressus and A. truncatus from the basal for Pentatomomorpha family Aradidae, we found a 10 bp motif TTAGGGATGG. While the available data allowed us to present two alternative hypotheses about the evolution of telomeric motifs in Heteroptera, further data are needed to verify them, especially for the yet unstudied basal infraorders Enicocephalomorpha, Dipsocoromorpha, and Leptopodomorpha. Full article

The whitefly Bemisia tabaci (Hemiptera: Aleyrodoidea) causes direct feeding damage to crop plants and transmits pathogenic plant viruses, thereby threatening global food security. Although whitefly-infecting RNA viruses are known and proposed as biocontrol agents, no insect DNA virus has been found in any member of Aleyrodoidea. Using rolling circle amplification (RCA) of viral DNA from whiteflies collected from crop fields in Morocco, followed by Illumina sequencing of the RCA products, we found a novel insect single-stranded (ss) DNA parvovirus (family Parvoviridae) in addition to plant ssDNA geminiviruses transmitted by whiteflies. Based on its genome organization with inverted terminal repeats and evolutionarily conserved proteins mediating viral DNA replication (NS1/Rep) and encapsidation (VP), encoded on the forward and reverse strands, respectively, we named this virus Bemisia tabaci ambidensovirus (BtaDV) and classified it as a founding member of a new genus within the subfamily Densovirinae. This subfamily also contains three distinct genera of ambisense densoviruses of other hemipteran insects (Aphidoidea, Coccoidea, and Psylloidea). Furthermore, we provide evidence for the genetic variants of BtaDV circulating in whitefly populations and for its partial sequences integrated into the B. tabaci genome, with one integrant locus potentially expressing a fusion protein composed of viral Rep endonuclease and host DNA-binding domains. This suggests a long-term virus-host interaction and neofunctionalization of BtaDV-derived endogenous viral elements. Full article

Agriculture plays an essential role in meeting global food demand, and so effective pest control is crucial. Aphids (Hemiptera: Aphididae) are a significant problem for many crops worldwide, and cause crop losses. They are considered one of the most important groups of pests in the world. Aphid parasitoids are very important as biological agents, both for their effectiveness and their host range selectivity. This study provides a review of these groups of parasitoids and their possible role and use in aphid biological control. Two groups of primary parasitoids, Aphelinidae and Braconidae: Aphidiinae, are the main groups that can be used in the biological control of aphids. There is also a diversity of hyperparasitoids whose hosts are these primary parasitoids and therefore are likely to be detrimental to the biological control programs: Megaspilidae in the superfamily Ceraphronoidea, the following Chalcidoidea families: Encyrtidae, Eulophidae, Moranilidae, Pteromalidae, and Signiphoridae, and Cynipoidea: Figitidae: Charipinae. Records of Mymaridae emerging from aphids, while assumed to be obligate egg-parasitoids, are discussed. Dichotomous keys are provided to identify the superfamilies, families and most important genera associated with aphids. Full article

Seventeen species of the mali-group of Aphelinus (Hymenoptera: Aphelinidae) are reviewed worldwide, including three new species, and five previously described species in China. The mali-group was defined by a combination of characters: head and body dark with parts of metasoma pale; fore wing with a complete row of setae inside the linea calva, or also only with a few setae in the angle between the linea and marginal vein; legs with mesocoxae, metacoxae and metatibia dark, metafemur pale. In this paper, three new species, Aphelinus tuberocephalus Wang & Huang, sp.n., Aphelinus hainanensis Wang & Huang, sp.n. and Aphelinus ruellia Wang & Huang, sp.n., are described and illustrated, with notes on one species, Aphelinus coreae Hopper & Woolley, new to China. A revised key to species of the mali-group is provided. Mitochondrial (COI) partial sequences were obtained successfully for A. tuberocephalus, A. hainanensis, A. ruellia and A. coreae. Full article

Expanding on previous efforts to survey the visual opsin repertoires of the Hemiptera, this study confirms that homologs of the UV- and LW-opsin subfamilies are conserved in all Hemiptera, while the B-opsin subfamily is missing from the Heteroptera and subgroups of the Sternorrhyncha and Auchenorrhyncha, i.e., aphids (Aphidoidea) and planthoppers (Fulgoroidea), respectively. Unlike in the Heteroptera, which are characterized by multiple independent expansions of the LW-opsin subfamily, the lack of B-opsin correlates with the presence of tandem-duplicated UV-opsins in aphids and planthoppers. Available data on organismal wavelength sensitivities and retinal gene expression patterns lead to the conclusion that, in both groups, one UV-opsin paralog shifted from ancestral UV peak sensitivity to derived blue sensitivity, likely compensating for the lost B-opsin. Two parallel bona fide tuning site substitutions compare to 18 non-corresponding amino acid replacements in the blue-shifted UV-opsin paralogs of aphids and planthoppers. Most notably, while the aphid blue-shifted UV-opsin clade is characterized by a replacement substitution at one of the best-documented UV/blue tuning sites (Rhodopsin site 90), the planthopper blue-shifted UV-opsin paralogs retained the ancestral lysine at this position. Combined, the new findings identify aphid and planthopper UV-opsins as a new valuable data sample for studying adaptive opsin evolution. Full article

Insect species are subjected to disparate selection pressure due to various biotic and abiotic stresses. Management practices including the heavy use of chemical insecticides and introduction of insect-resistant plant cultivars have been found to accelerate these processes. Clearly, natural selection coupled with human intervention have led to insect adaptations that alter phenotypes and genetic structure over time, producing distinct individuals with specialized traits, within the populations, commonly defined as biotypes. Biotypes are commonly found to have better fitness in the new environment and, in the case of aphids, the most commonly studied system for biotypes, have the ability to successfully infest previously resistant host plants and new species of host plants. Although a large number of studies have explored biotypes, the concept for defining biotypes varies among scientists, as we lack a consistency in estimating biotype behavior and their variation within and between biotypes. The concept of biotypes is even more complicated in aphid species (Aphidoidea), as they undergo parthenogenetic reproduction, making it difficult to understand the source of variation or quantify gene flow. In this review, we aim to illuminate the concept of biotype and how it has been used in the study of aphids. We intend to further elaborate and document the existence of aphid biotypes using sugarcane aphid (Melanaphis sacchari) as a model to understand their differences, level of variation, evolution, and significance in pest management. Full article

Our aim was to investigate the among-populations diversity of prey composition in Eurasian Reed Warblers’ diets via their droppings, both to assess the ecological validity of this sampling method and to test whether the prey species most abundant in fecal samples were also the most present in the Italian study site. We collected fecal samples at four sites throughout Italy, for a total of 144 samples. Within reedbeds, the breeding habitat of the Eurasian Reed Warbler, we also collected arthropods by carrying out entomological sweepings at one of the study sites. Within the fecal samples, we identified dozens of prey species, belonging mainly to Araneae, Coleoptera, Diptera, Hymenoptera and Aphidoidea taxa, whose compositions were not statistically different among sites. The commonest prey species were Coleoptera in the droppings (68.5%) and Diptera in the reedbeds (31.3%), although the latter was less numerous in the fecal samples. The diets of different Italian populations of Eurasian Reed Warbler emerging from our study underline a strong Coleopteran presence, without differences across Italy. Fecal samples appear to be an exhaustive method to study variation in Eurasian Reed Warbler diet and its ecological importance; however, although potential caveats do exist, such as the possible under-representation of Diptera. Full article

Aphids (Hemiptera: Aphidoidea) are among the most detrimental insects for agricultural plants, and their management is a great challenge in agronomical research. A new class of proteins, called Bacteriocyte-specific Cysteine-Rich (BCR) peptides, provides an alternative to chemical insecticides for pest control. BCRs were initially identified in the pea aphid Acyrthosiphon pisum. They are small disulfide bond-rich proteins expressed exclusively in aphid bacteriocytes, the insect cells that host intracellular symbiotic bacteria. Here, we show that one of the A. pisum BCRs, BCR4, displays prominent insecticidal activity against the pea aphid, impairing insect survival and nymphal growth, providing evidence for its potential use as a new biopesticide. Our comparative genomics and phylogenetic analyses indicate that BCRs are restricted to the aphid lineage. The 3D structure of BCR4 reveals that this peptide belongs to an as-yet-unknown structural class of peptides and defines a new superfamily of defensins. Full article

Plant stress caused by aphid foraging can cause a number of disturbances in its vital functions. The degree of disturbance depends on the duration of the stress factor and its intensity. The aim of this study has been to evaluate the impact of aphids (Acyrthosiphon pisum Harris, Rhopalosiphum padi L., Myzus persicae Sulzer) foraging on plants and the intensity of photosynthesis and transpiration in several crops (Pisum sativum L., Triticum aestivum L., Brassica napus L.). The laboratory experiment conducted for this purpose revealed that aphids feeding on plants affect the course of photosynthesis and transpiration in crops. Statistically significant correlations were determined between the efficiency of these processes and the number of aphids as well as the duration of their foraging. The average values of the intensity of photosynthesis and transpiration in the test crops were found to increase with the increasing number of aphids in a short feeding period (day 5). A longer foraging time (10, 15 days) coincided with a decrease in the intensity of photosynthesis and transpiration. A detailed analysis of the three species of crops demonstrated that the effect of the biotic stressors on the course of the analysed processes could vary, depending on the host plant. Full article

Combined seed treatment with neonicotinoids and fungicides offers a potential control measure for pest management at the wheat seeding stage. In this study, a novel, highly-efficient seed-coating agent was prepared using thifluzamide, fludioxonil, and clothianidin as its active components and other additives (abbreviated to TFC). Laboratory experiments and field trials revealed a positive effect on germination, plant height, and root length, with 90% control efficiency on wheat sharp eyespots and aphid infestations. Meanwhile, the distribution of thifluzamide, fludioxonil, and clothianidin residues in the wheat plants at harvest was below 0.05 mg/kg both at the recommended dosage and at 2.0 times the recommended dose. Furthermore, an artificial soil assay of biotoxicity in earthworms revealed a low level of toxicity at LC₅₀ > 10 mg/kg. Overall, these findings suggest that TFC has the potential to control major soil-borne diseases and pest infestations in wheat, offering an environmentally-friendly alternative to more toxic pesticides. Full article

In order to provide more evidence for the evaluation of the ecological risks of transgenic maize, arthropod population dynamics and biodiversity in fields planted with two kinds of transgenic maize (DBN9868, expressing the PAT and EPSPS genes, and DBN9936, expressing the Cry1Ab and EPSPS gene) were investigated by direct observation and trapping for three years. The recorded arthropod species belonged to 19 orders and 87 families, including Aphidoidea, Chrysomelidae, Coccinellidae, Chrysopidae and Araneae. The species richness, Shannon–Wiener diversity index, Pielou evenness index, dominance index and community similarity index of arthropod communities in maize fields were statistically analyzed, and the results showed that (1) the biodiversity difference of arthropod communities between transgenic maize and non-transgenic maize was smaller than that between different conventional cultivars; (2) the differences between ground-dwelling arthropod communities were less obvious than those between plant-inhabiting arthropod communities; and (3) Lepidoptera, the target pests of Bt maize, were not the dominant population in maize fields, and the dominant arthropod population in maize fields varied greatly between years and months. Combining those results, we concluded that the transgenic maize DBN9868 and DBN9936 had no significant effect on the arthropod communities in the field. Full article

Turnip mosaic virus (TuMV) is an important threat to the yield and quality of brassica crops in China, and has brought serious losses to brassica crops in the Far East, including China and the north. Aphids (Hemiptera, Aphidoidea) are the main mediators of TuMV transmission in field production, and not only have strong virus transmission ability (small individuals, strong concealment, and strong fecundity), but are also influenced by the environment, making them difficult to control. Till now, there have been few studies on the resistance to aphids in brassica crops, which depended mainly on pesticide control in agriculture production. However, the control effect was temporarily effective, which also brought environmental pollution, pesticide residues in food products, and destroyed the ecological balance. This study reviews the relationship among brassica crop–TuMV, TuMV–aphid, and brassica crop–aphid interactions, and reveals the influence factors (light, temperature, and CO₂ concentration) on brassica crop–TuMV–aphid interactions, summarizing the current research status and main scientific problems about brassica crop–TuMV–aphid interactions. It may provide theoretical guidance for opening up new ways of aphid and TuMV management in brassica crops. Full article

Fungi can synthesize a wealth of secondary metabolites, which are widely used in the exploration of lead compounds of pharmaceutical or agricultural importance. Beauveria, Metarhizium, and Cordyceps are the most extensively studied fungi in which a large number of biologically active metabolites have been identified. However, relatively little attention has been paid to Purpureocillium lilacinum. P. lilacinum are soil-habituated fungi that are widely distributed in nature and are very important biocontrol fungi in agriculture, providing good biological control of plant parasitic nematodes and having a significant effect on Aphidoidea, Tetranychus cinnbarinus, and Aleyrodidae. At the same time, it produces secondary metabolites with various biological activities such as anticancer, antimicrobial, and insecticidal. This review attempts to provide a comprehensive overview of the secondary metabolites of P. lilacinum, with emphasis on the chemical diversity and biological activity of these secondary metabolites and the biosynthetic pathways, and gives new insight into the secondary metabolites of medical and entomogenous fungi, which is expected to provide a reference for the development of medicine and agrochemicals in the future. Full article