Search Results (77)

The entomopathogenic fungus Beauveria bassiana (Hypocreales: Cordycipitaceae) is widely used as a biological control agent, yet its efficacy against orthopteran pests remains poorly characterized. In this study, we evaluated the susceptibility of second-, third-, and fourth-instar nymphs of the Italian locust, Calliptamus italics (Orthoptera: Acrididae), to B. bassiana strain PPRI5339 under controlled laboratory conditions. Nymphs were exposed to six conidial concentrations (1 × 10³ to 1 × 10⁸ conidia/mL) via treated food, with mortality recorded over 10 days. The fungus caused significant, dose- and time-dependent mortality across all instars. Second-instar nymphs exhibited the highest susceptibility, with an LC₅₀ of 5.8 × 10⁵ conidia/mL and an LT₅₀ of 3.1 days at the highest concentration. Susceptibility decreased with advancing developmental stage; fourth-instar nymphs required higher concentrations and longer exposure to achieve comparable mortality (LC₅₀ = 2.3 × 10⁶ conidia/mL; LT₅₀ = 4.5 days). Cox proportional hazards analysis confirmed that the mortality hazard was significantly lower for third (HR = 0.66) and fourth (HR = 0.51) instars compared to second instars (HR = 1.00). These results demonstrate that B. bassiana is pathogenic to C. italicus, with pronounced stage-dependent susceptibility. Full article

Sterol Carrier Protein X (SCP-x) is an evolutionarily conserved lipid transport protein that plays important roles in sterol metabolism. In insects, cholesterol is an essential component of cellular membranes and the precursor of ecdysteroids, yet insects cannot synthesize cholesterol de novo and must obtain it from dietary sources. However, the functional role of SCP-x in cholesterol absorption and transport in insects remains poorly understood. In this study, the SCP-x gene from the migratory locust Locusta migratoria was identified and characterized using transcriptomic data from the midgut and fat body. The full-length LmSCP-x encodes a 404-amino-acid protein containing both the 3-oxoacyl-CoA thiolase domain and the sterol carrier protein-2 domain. Expression analysis revealed that LmSCP-x is predominantly expressed in the midgut and fat body, and subcellular localization experiments showed that the protein is mainly distributed in the cytoplasm. RNA interference-mediated knockdown of LmSCP-x significantly reduced cholesterol levels in the fat body and delayed nymphal development. Structural prediction using AlphaFold 3 further revealed a conserved three-dimensional structure of the SCP-2 domain, and molecular docking identified key amino acid residues involved in cholesterol binding, which were subsequently validated by bio-layer interferometry assays. Together, these results demonstrate that LmSCP-x plays a crucial role in cholesterol transport in L. migratoria and provide new insights into sterol metabolism in insects, offering potential targets for the development of novel pest management strategies. Full article

The Moroccan locust (Dociostaurus maroccanus) is one of the most economically significant locust species in the Caucasus and Central Asia. In the past, the Mediterranean region also experienced severe damage to crops and pastures, until widespread grassland conversion to cropland began in the second half of the 20th century. However, climate change, environmental shifts, land-use changes, cropland abandonment, and overgrazing are likely to alter the spatial distribution and outbreak patterns of this pest. Understanding potential changes and geographic shifts is essential for proactive pest management, including effective monitoring and control strategies. In this study, we apply Ecological Niche Modelling (ENM) using 12 machine learning algorithms, historical survey data covering the species’ full distribution range, and relevant abiotic variables to identify the most suitable areas for potential mass breeding during 1991–2020 and the near future (2021–2040), based on the “middle-of-the-road” Shared Socioeconomic Pathway (SSP2-4.5) scenario. Our results indicate significant regional shifts. Notably, breeding suitability is projected to increase in parts of Greece, Turkey, Armenia, Georgia, Kyrgyzstan, and Tajikistan. In contrast, countries such as Turkmenistan, Afghanistan, Pakistan, and Spain are likely to experience a decline in optimal breeding areas. The forecast results support field observations of a geographical shift northward and toward higher altitudes. Additionally, higher temperatures in suitable areas suggest more drought-like conditions, which typically promote locust population explosions and outbreaks. If left unaddressed, such outbreaks can cause severe economic damage to affected regions. Full article

This study was conducted in the Xinjiang region, China, along the Sino-Kazakh border, an area recognized as high-risk for locust outbreaks and characterized by ongoing shifts in dominant pest species. This study systematically examined the structural characteristics of locust communities across different grassland types and identified the underlying environmental driving mechanisms. Field surveys were conducted to assess the diversity characteristics, density variations, and niche width of the locust communities across the different grassland types. The locust community in the mountain meadows had a significantly lower Shannon diversity index compared with the other grassland types (p < 0.05). Although the Simpson dominance index and Pielou evenness index were also the lowest in the mountain meadows, these differences were not statistically significant (p > 0.05). Permutational multivariate analysis of variance (PermANOVA) revealed highly significant differences in locust density among the grassland types (p = 0.001). Ecological niche analysis revealed stronger interspecific competition in the lowland meadow, and weaker competition in the temperate steppe-enriched deserts and temperate desert grasslands. Structural equation modeling and random forest analysis identified soil organic, plant total potassium, and soil pH as the key factors driving locust community structure across grassland types. This study clarifies the diversity patterns of locust communities in the Xinjiang region along the Sino-Kazakh border and provides empirical data to better understand locust community structure and distribution. It also offers a scientific basis for developing sustainable locust management strategies. Full article

The Asian migratory locust (Oedaleus decorus asiaticus) is a major grassland pest in northern China, with outbreak dynamics closely linked to phase transition mediated by chemical communication. This study focused on a chemosensory protein, OasiCSP12, to explore its potential role in this process. We analyzed its expression patterns via qRT-PCR, purified the recombinant protein, and identified potential ligands through fluorescence competitive binding assays. Structural insights were gained through homology modeling, molecular docking, and molecular dynamics simulations, with binding energetics assessed using MM/PBSA. Results showed that OasiCSP12 expression is phase- and sex-specific, being significantly upregulated in gregarious adult antennae. The protein bound selectively to 15 locust body-surface volatiles, including aldehydes and esters. Its structure features a hydrophobic binding cavity where van der Waals interactions, primarily predicted to be mediated by residues Val86, Leu71, and Trp101, likely stabilize ligand complexes. These findings indicate that OasiCSP12 is potentially associated with both chemical perception and phase regulation in O. d. asiaticus, providing a candidate target for developing behavior-based green control strategies against this pest. Full article

Locusta migratoria (Orthoptera: Acrididae) is a major agricultural pest, characterized by its strong reproductive capacity and rapid reproduction rate. Consequently, identifying novel targets to control or reduce the fecundity of locusts is of significant practical importance. Insulin/insulin-like growth factor signaling (IIS) and the DEAD-box RNA helicase 3 (DDX3) exhibit extensive functional convergence; both govern key life-history traits in insects, including lifespan, metabolic homeostasis, and fecundity. Strikingly, each pathway can influence oogenesis through Notch signaling. Thus, we hypothesize that DDX3 may modulate insect reproduction associated with this pathway. After silencing DDX3 through RNA interference (RNAi), we found that the key genes of IIS were significantly downregulated and the content of trehalose and glycogen decreased significantly, proving that DDX3 inhibits reproduction associated with IIS. In addition, DDX3 interference led to a marked reduction in the mRNA expression of Vgs (VgA/B) and JHAMT, which was accompanied by a significant decrease in ovarian development. Furthermore, integrating our previous findings, we posit that DDX3 engages in locust reproduction via the regulation of pivotal IIS pathway genes such as InR and FOXO, thereby completing the putative regulatory circuitry through which DDX3 modulates reproductive processes. Our findings deepen the understanding of the endogenous circuitry governing locust reproduction and provide novel theoretical justification for targeting DDX3 in locust management strategies. Full article

The Moroccan locust Dociostaurus maroccanus (Thunberg, 1815) (Orthoptera: Acrididae) is recognized as a serious pest of pastures and crops in many Mediterranean countries. So far, the identification of chemical compounds involved in intraspecific communication has been elusive, with only one male-specific compound, namely (2E,7R,11R)-3,7,11,15-tetramethylhexadec-2-enal (2E,7R,11R-phytal), proposed as candidate sex pheromone component. Previous works reported that males also release the sex-specific long-chain aldehydes tetradecanal and hexadecanal, although no evidence of their role in chemical signaling has been presented so far. Here we additionally report another male-specific compound, viz. pentadecanal, and also report the electroantennographic and behavioral responses of virgin and mated females to these three aldehydes. We first demonstrated that their release is age-dependent, with emission overall peaking at 1–2 weeks after fledging. Solid-phase microextraction analyses from male hind legs suggest that these aldehydes are released from this body part. Overall, the antennae of virgin and mated females exhibited a dose-dependent response to increasing concentrations of each aldehyde, except for the response of virgin females to hexadecanal. Significant differences were observed between virgin and mated females at all doses of hexadecanal, while the mating status did not influence the response to tetradecanal and pentadecanal. Furthermore, the behavioral response of females varied according to their mating status. Specifically, mated females showed a significant preference for tetradecanal and pentadecanal, whereas a slight but non-significant attraction to hexadecanal was observed on virgin females. These findings provide new insights into the sexual communication of the species, although further research is needed to decipher their ecological function, especially on mated females. Full article

Locusta migratoria manilensis (Meyen) is a highly destructive insect pest worldwide. However, excessive reliance on insecticides has resulted in significant environmental pollution. Biocontrol complexes combine two or more BCAs to address the limitations of individual agents. However, biocontrol complex for locust control has been rarely reported. Here, we propose BioControl 3.0, which integrates Metarhizium anisopliae var. acridum (Driver and Milner) and Carabus smaragdinus (Fischer von Waldheim) for locust control. We evaluated this system through a series of laboratory bioassays and semi-field cage experiments, comparing single-agent applications, sequential combinations (BioControl 2.0), and predator-mediated delivery (BioControl 3.0), and quantified locust mortality and interaction effects between predation and infection We found that M. anisopliae caused >85% mortality of locust nymphs at 1 × 10⁸ conidia/mL (LT₅₀ ≈ 6 days) while exhibiting negligible virulence toward C. smaragdinus. BioControl 2.0 (sequential application) increased mortality compared to single agents. However, this approach revealed a significant negative interaction between predation and infection, which limited the total control efficacy. BioControl 3.0 (predator-vectored fungus) achieved the highest corrected mortality, with predation and infection acting independently and additively (no detectable antagonistic interaction). By leveraging a predatory vector, BioControl 3.0 decouples negative interaction and harnesses dual biotic pressures, offering a cost-effective, environmentally benign alternative to conventional locust control. Our findings provide a blueprint for designing integrated predator-pathogen complexes and optimizing deployment strategies for sustainable management of locust outbreaks. Full article

Locusts represent a persistent global agricultural pest, responsible for significant crop losses and socio-economic repercussions. The initiation of chemical control measures dates back to the late 19th century, with the use of poisoned baits, before advancing in the mid-20th century with the introduction of organochlorines, such as dieldrin. Despite their efficacy, the associated environmental, ecological, and human health risks led to the prohibition of dieldrin by the United States and the FAO by 1988. The demand for insecticides with reduced persistence and toxicity prompted the establishment of international organizations to coordinate locust research and management. In recent decades, chemical control has transitioned towards compounds with diminished persistence and selective agents. Concurrently, research has progressed in the development of bioinsecticides, notably Metarhizium acridum, and has reinforced preventive strategies. Emerging technologies, including remote sensing and machine learning, have facilitated early monitoring and predictive modeling, thereby enhancing outbreak forecasting. These tools support proactive, targeted interventions and are consistent with Integrated Pest Management principles, promoting more sustainable and ecologically responsible locust control strategies. Full article

The migratory locust (Locusta migratoria), is a destructive pest in agriculture and ecological conservation, characterized by its unique phase polyphenism (phase change). Parthenogenesis, defined as oviparous reproduction without fertilization, has been studied less extensively than fertilized reproduction, with particularly scarce research on parthenogenesis in migratory locust. This study investigates the relationship between parthenogenesis and the phase change in migratory locusts. Through comparative studies between two phases, we found that solitary locusts exhibit a higher parthenogenesis capacity compared to gregarious locusts, as evidenced by greater total oviposition quantity and higher hatching rates. However, parthenogenesis resulted in significantly lower hatching rates compared to sexually fertilized females, with distinct differences in oviposition dynamics and hatching patterns. Furthermore, we observed that gregarious locusts, when isolated after eclosion, exhibited increased parthenogenetic capacity, depending on their juvenile density. Together, this study provides insights into the understanding of insect parthenogenesis and lays basis for the potential underlying mechanism. Full article

The desert locust (Schistocerca gregaria) represents one of the most destructive agricultural pests globally, renowned for its ability to form massive swarms that can devastate crops and threaten food security across vast regions. Despite the widespread application of the CRISPR/Cas9 gene-editing system in several insect orders, its utilization in locusts, particularly in the desert locust, has remained relatively unexplored. We established a CRISPR/Cas9-mediated gene-editing workflow for the desert locust using gene encoding for neuropeptide corazonin (Crz) as a target. We also analyzed the phenotypic and physiological characteristics of the mutant using paraffin sectioning, HE staining, and chitin staining techniques. Our findings revealed that while Crz knockout desert locusts were viable and maintained normal fertility, they exhibited striking phenotypic alterations, including albinism and a significant reduction in cuticle thickness. These observations not only highlight the functional role of Crz in pigmentation and cuticle development but also underscore the potential of CRISPR/Cas9 as a powerful tool for dissecting gene function in locusts. Furthermore, the successful application of CRISPR/Cas9 in desert locusts also paves the way for similar genetic studies in other non-model insects, expanding the scope of functional genomics in entomology. Full article

Insects are among the most diverse and abundant organisms on Earth, and their population dynamics are strongly influenced by entomopathogenic fungi. This study examines the role of carbon and nitrogen metabolism in the virulence of the entomopathogenic fungus Metarhizium rileyi against the migratory locust, Locusta migratoria. The findings demonstrate that the capacity of M. rileyi to utilize different carbon and nitrogen sources is a key factor in its virulence. Specifically, two strains of M. rileyi (PPDB201006 and SZCY201010) exhibited distinct metabolic abilities, with PPDB201006 displaying superior growth and enzyme activities on various carbon and nitrogen sources compared to SZCY201010. These metabolic differences were associated with significant variations in virulence, as PPDB201006 induced higher mortality rates in L. migratoria than SZCY201010. Metabolomics analysis revealed that infection by M. rileyi led to substantial alterations in the hemolymph metabolites of L. migratoria, particularly in organic acids, amino acids, sugars, and lipids. These results emphasize the significance of carbon and nitrogen metabolism in the pathogenicity of entomopathogenic fungi and offer new perspectives for optimizing their application as biological control agents. This study not only improves our understanding of fungal virulence mechanisms but also contributes to the development of more effective and sustainable pest management strategies. Full article

The effects of climate change are particularly pronounced in cities, where urban green infrastructure—such as trees, parks, and green spaces—plays a vital role in both climate adaptation and mitigation. This study assesses the carbon sequestration potential of urban forests in Budapest, the capital city of Hungary, which lies at the intersection of the Great Hungarian Plain and the Buda Hills, and is traversed by the Danube River. The city is characterized by a temperate climate with hot summers and cold winters, and a diverse range of soil types, including shallow Leptosols and Cambisols in the limestone and dolomite hills of Buda, well-developed Luvisols and Regosols in the valleys, Fluvisols and Arenosols in the flood-affected areas of Pest, and Technosols found on both sides of the city. The assessment utilizes data from the National Forestry Database and the Copernicus Land Monitoring Service High Resolution Layer Tree Cover Density. The results show that Budapest’s urban forests and trees contribute an estimated annual carbon offset of −41,338 tCO₂, approximately 1% of the city’s total emissions. The urban forests on the Buda and Pest sides of the city exhibit notable differences in carbon sequestration and storage, age class structure, tree species composition, and naturalness. On the Buda side, older semi-natural forests dominated by native species primarily act as in situ carbon reservoirs, with limited additional sequestration capacity due to their older age, slower growth, and longer rotation periods. In contrast, the Pest-side forests, which are primarily extensively managed introduced forests and tree plantations, contain a higher proportion of non-native species such as black locust (Robinia pseudoacacia) and hybrid poplars (Populus × euramericana). Despite harsher climatic conditions, Pest-side forests perform better in carbon sink capacity compared to those on the Buda side, as they are younger, with lower carbon stocks but higher sequestration rates. Our findings provide valuable insights for the development of climate-resilient urban forestry and planning strategies, emphasizing the importance of enhancing the long-term carbon sequestration potential of urban forests. Full article

Yunnan is located on the southwest border of China, with a complex geographical environment and rich biodiversity, which is the first stop for many migratory pests to enter China. In recent years, Ceracris kiangsu has migrated into China through the China–Laos border line. The migratory C. kiangsu has shown typical characteristics of migratory locusts, which has seriously jeopardized the ecological security, biosecurity and food security of China. In order to prevent and control C. kiangsu from the source as soon as possible, this study used hotspot analysis and trajectory analysis to clarify the migration dynamics, source regions and migration corridors of C. kiangsu. The results showed that the migratory C. kiangsu was mainly distributed in the towns of Jiangcheng County, and the source regions were concentrated in Phongsaly, Laos. There are three cross-border migration corridors of C. kiangsu, among which the Laos–Niuluohe border migration corridor running through the entire migration cycle is the most important corridor. The study answered three key questions about the prevention and control of C. kiangsu. Ascertaining when C. kiangsu arrived at Yunnan, where it came from, and where the population then went will greatly improve the efficiency of the prevention and control of C. kiangsu as well as provide a theoretical basis for subsequent monitoring and early warning. Full article

This study employed an integrated approach combining multi-source remote sensing data and the MaxEnt model to systematically assess the ecological niche characteristics of the oriental migratory locust (Locusta migratoria manilensis) in Hainan Island, while projecting the evolution of its suitable habitats under both historical and future climate scenarios (up to 2040). Firstly, we synthesized traditional climate, soil, and topography data with remote sensing data to characterize the suitable areas of the oriental migratory locust based on MaxEnt model (with high accuracy of AUC = 0.935 and TSS = 0.76). Subsequently, six dominant environmental variables—precipitation in April (PRE04), precipitation in September (PRE09), maximum temperature in August (TMAX08), minimum temperature in December (TMIN12), NDVI in February (NDVI02), and NDVI in May (NDVI02)—were identified as key predictors. Their threshold values were determined, with PRE04, PRE09, TMAX08, and TMIN12 ranging from 39 to 44 mm, 196 to 223 mm, 31.1 to 32.2 °C, and 17.7 to 18.0 °C in high-suitability zones, respectively. Finally, these six predictors were used to assess habitat suitability across Hainan Island for both the 2001–2020 and 2021–2040 periods. Under historical climate conditions, highly suitable areas (505 km², 1.41% of total land area) were concentrated in the western and northeastern regions, particularly in Dongfang City (46.27%), Ledong Li Autonomous County (32.91%), and Changjiang Li Autonomous County (18.39%). Future projections indicate significant habitat expansion, with total suitable areas increasing by 13.4–42.0% and highly suitable areas reaching 571–831 km² by 2040. The study highlights the critical Dongfang–Danzhou–Ledong region for targeted locust control, providing scientific support for pest management in tropical island ecosystems under climate change. Full article