Insect Science最新文献

Carbon dioxide (CO₂) plays a crucial role in the host search/localization process of bed bugs, Cimex lectularius L., and Cimex hemipterus (F.). Current research on the CO₂ perception by bed bugs mainly focuses on their behavioral responses, and the molecular mechanisms are still unclear. In addition, existing research has mainly been conducted on C. lectularius with very little research on C. hemipterus. In this study, we investigated the behavioral response of C. hemipterus to CO₂ and analyzed the role of antennae in the CO₂ sensing process. Then, potential CO₂ receptor genes were screened through antennal RNA sequencing and tissue-specific expression profiling analysis. Finally, the function of CO₂ receptors was further validated using RNA interference. Results indicated that increasing the CO₂ concentration in the air not only stimulated the activity of C. hemipterus, but also presented a directional attraction effect on them. CO₂, with a concentration of 0.06%-1.8%, had a significant attraction effect on C. hemipterus. Removal of the antennae led to the loss of bed bugs' preference for CO₂. Four candidate CO₂ receptor genes (ChGR1, ChGR2, ChGR3, and ChGR4) were identified through transcriptomic analysis of the bed bug antennae, and 3 of them (ChGR2, ChGR3, and ChGR4) were highly expressed in the antennae. Silencing ChGR2 or ChGR4 individually led to a significant reduction or even loss of CO₂ sensing ability in C. hemipterus. In conclusion, CO₂ can induce the host searching behavior of C. hemipterus; moreover, ChGR2 and ChGR4 are crucial for detecting CO₂ in C. hemipterus.

Harmonia axyridis was originally considered and used as a biocontrol agent throughout the world. But its effectiveness has turned into a serious detriment to ecosystems, as it has become an invasive and harmful species, gradually displacing native coccinellid populations. Its invasive success mostly relies on its voracity, aggressiveness, and dominance in intraguild predation (IGP) interactions. Aggressiveness is a major behavioral characteristic known to influence IGP occurrence and outcome. So, what if H. axyridis were confronted with more aggressive competitors? To understand the vulnerability of H. axyridis to aggressive competitors, we confronted it with an IGP interaction involving two artificially selected lines of the generalist predator Nabis americoferus (one aggressive and one docile) in the presence of extraguild prey (Myzus persicae). Two hypotheses were formulated: (1) the IGP intensity toward H. axyridis is positively correlated with the intraguild predator's aggressiveness, and (2) the IGP intensity decreases in the presence of extraguild prey for both the aggressive and docile lines. Results showed that, as expected, the aggressive line displayed a higher IGP rate on H. axyridis than the docile line, supporting the first hypothesis. The second hypothesis was also supported, since extraguild prey availability led to a decrease in IGP for both lines. Apart from providing insights into the relationship between aggressiveness and IGP occurrence, the discussion focuses on the consequences for H. axyridis in the field as an invasive species and as a biological control agent.

Pests are a major cause of agricultural and economic losses. Their high reproduction rate remains a considerable challenge for pest control. Insects with impaired border cell migration during oogenesis are unable to reproduce, offering a potential method to reduce their population growth. To fully understand the effects of the deubiquitinating enzyme (DUB) family on border cell migration, we generated 38 transgenic fly lines overexpressing distinct DUBs, using Gal4/UAS technology to drive their expression in border cells. Overexpression of usp10 led to reductions in ovary size, egg production, and egg hatchability. Interestingly, knockdown of usp10 also resulted in the same defects, indicating the importance of maintaining proper Usp10 levels for oogenesis. In addition, the immunofluorescence and confocal microscopy analysis revealed that either overexpression or knockdown of usp10 disrupts adherens junctions and actin filament distribution, ultimately leading to delayed border cell migration. Taken together, this study highlights the critical role of Usp10 in Drosophila fertility, and suggests Usp10 as a potential target for pest management.

The sterile insect technique (SIT) plays an important role in environmentally sustainable pest management. Its effectiveness hinges on specialized genetic tools called genetic sexing strains (GSSs), which enable the production and release of sterile male insects while excluding females. A collaborative initiative by the International Atomic Energy Agency (IAEA), designated as D44003 "A generic approach for the development of genetic sexing strains for Sterile Insect Technique applications," aimed to establish a universal framework for developing GSSs applicable to various pest species. This overview summarizes findings from 17 research studies, including laboratory models and field pests. The studies focused on enhancing genetic markers, genome editing, understanding sex determination, creating temperature-sensitive lethal systems, refining radiation protocols, and improving strain components. Collectively, these efforts demonstrate that a versatile, species-independent approach is both feasible and practical in real-world pest control efforts. This progress paves the way for the broader adoption of the SIT, promising a significant advance in integrated pest management.

Plutella xylostella, a major pest of cruciferous crops, has rapidly evolved resistance to pyrethroid insecticides, posing a significant threat to sustainable agriculture. Among the various resistance mechanisms, glutathione S-transferases (GSTs) play a pivotal role in the detoxification of xenobiotics. However, the molecular basis underlying their interaction with pyrethroids remains poorly understood. In this study, we investigated the metabolic function of PxGSTD5, a Delta-class GST from P. xylostella, in the detoxification of two widely used pyrethroids-esfenvalerate and deltamethrin-through a comprehensive approach integrating enzyme kinetics, in vitro metabolism assays, molecular docking, and site-directed mutagenesis. Our results revealed that PxGSTD5 exhibited substantial metabolic activity toward esfenvalerate (31.65%) and deltamethrin (41.20%). Molecular docking and mutagenesis analyses identified Ser12, His41, Tyr116, and Phe120 as key amino acid residues responsible for substrate binding and catalysis. Alanine substitution of these residues significantly impaired the enzyme's metabolic efficiency, underscoring their critical roles in GST-mediated detoxification. This study provides direct biochemical and structural evidence for the involvement of PxGSTD5 in pyrethroid metabolism and resistance in P. xylostella. These findings offer valuable insights into the molecular mechanisms of detoxification and support the rational design of next-generation insecticides capable of overcoming GST-mediated resistance, thereby contributing to improved pest management strategies.

The Bactrocera genus includes highly invasive fruit and vegetable pest species such as Bactrocera dorsalis, Bactrocera correcta, and Bactrocera oleae. The sterile insect technique (SIT) is a biological control method used to suppress populations of the invasive Bactrocera fruit flies by releasing sterilized male insects that compete with wild males for mates, reducing reproduction and eventually pest numbers. The effectiveness of the SIT against insect pests can be enhanced through male-only releases, achieved via genetic sexing strains (GSS) that enable early-stage sex separation. To overcome limitations faced when developing a new GSS through the classical genetic approach, a novel "neoclassical approach" has been proposed, focusing on the identification of genetic markers, the induction of desired phenotypes through genome editing, and the linkage of selectable markers to male sex. In this study, we evaluated the white pupae gene as a selectable marker for GSS development in 3 Bactrocera species. The white pupae orthologous genes have been identified, and, through CRISPR/Cas9 mutagenesis, the 3rd exon of the white pupae gene was knocked out resulting in white pupae lines in Bactrocera dorsalis, Bactrocera correcta, and Bactrocera oleae species. These results demonstrate the applicability of CRISPR/Cas9-mediated disruption of the conserved white pupae gene as a selectable marker in multiple Bactrocera species, supporting the development of genetic sexing systems for SIT-based pest management.

The sterile insect technique, which consists of the mass production and release of sterile insects to control populations of pests and disease vectors, has been effectively used for decades. An important component of sterile insect technique field applications is the availability of sex separation systems that reliably and economically eliminate females from mass-reared sterile insect populations destined for field release. Genetic sexing strains are important for the effectiveness and cost-efficiency of insect population control programs, including sterile insect technique. Classical approaches to generate genetic sexing strains, such as irradiation-induced chromosomal translocations, have yielded stable strains for species like the Mediterranean fruit fly, Ceratitis capitata. However, significant efforts are needed to establish genetic sexing strains using classical genetic methods, as large-scale random mutagenesis and screening are needed. We introduce here a neoclassical genetic approach, leveraging CRISPR-based gene-editing to target known genes to develop selectable genetic markers, followed by genetic rescue in a male-specific manner to speed up the development of genetic sexing strains and enhance their precision, stability, and adaptability. The integration of molecular tools, genetic markers like the white pupae and temperature-sensitive lethal, and strategies for maintaining genetic stability are discussed. We also review the challenges and opportunities in applying classical, transgenic, and neoclassical genetic approaches to improve genetic sexing strains for pest management.

The detection and characterization of sex chromosome sequences is particularly important for major pest families, like the Tephritidae, whereas alternative pest management approaches, mainly involving male-only release programs, rely on the ability to target and manipulate sex-specific genomic regions, particularly those of the Y chromosome. However, resolving and detecting X and Y chromosome sequences at the chromosome level requires careful consideration of algorithmic outputs, especially in species where extensive sex chromosome markers are not available. Here, we present R-CQ and KAMY, two computational methods developed for the detection of sex chromosome-linked sequences through sex-specific short-read DNA sequencing datasets. We evaluate their performance on newly generated chromosome-level assemblies of four important Tephritid pest species: Ceratitis capitata, Bactrocera dorsalis, Bactrocera zonata, and Anastrepha ludens. By combining algorithmic predictions with a manual curation process, we assess the strengths and limitations of each method and provide a robust dataset of curated X- and Y-linked sequences. Overall, our results establish a framework for studying poorly characterized sex chromosome lineages and identifying sex-specific genomic regions, supporting the broader development of sex chromosome-based pest managements systems.

Insect vectors play a key role in the transmission of plant viruses, acting as major drivers of crop losses worldwide. Noncirculative plant viruses rely on brief and transient interactions with their insect vectors for successful transmission. Here, we focused on aphids (Aphidoidea), whiteflies (Aleyrodoidea), and mealybugs (Coccoidea), hemipterans of the suborder Sternorrhyncha, known for transmitting 95% of viruses in a noncirculative mode. Based on the current knowledge, we compared specific morphological and behavioral traits related to their stylets, the cuticular needle-like structures. This comparison shed some light on the leading role of aphids as vectors, owing to their highly specialized mouthparts and unique intracellular probing behavior. The review also discusses known key molecular interactions at the virus-stylet interface. Comparing these features across the 3 hemipteran superfamilies underscores how specific behavioral and anatomical traits set aphids apart, enabling their remarkable capacity to transmit stylet-borne, noncirculative viruses.

Reports of serious and widespread insect declines have been a source of concern for years, but long-term changes in migratory insect communities-which are important components of large-scale ecosystem functioning-are still little understood. Most migratory insects fly at high altitudes, making quantitative investigation problematic. Aerial trapping is the oldest sampling method, and generally still the only one that can provide information on species identity and adequately sample the smaller species. However, aerial sampling is laborious, and thus sampling periods are usually not continuous and sampling sites are sparsely scattered worldwide. To address these issues, we integrated existing data obtained by sampling from aerial platforms (and some high-mountain netting in East Asia) in a comprehensive analysis. We found that, between 1926 and 2017, the aerial density of high-flying migratory insects from samples taken about 200 m above Europe (eastern United Kingdom), North America (southern and central United States), and Asia (east-central China, India, and the Philippines), remained relatively stable overall. Additionally, some key migratory agricultural pests have significantly increased over this period, indicating that the non-pest portion of the aerial migrant community may have declined. Changes in the community structure of high-altitude migratory insects will be closely associated with large-scale ecosystem changes. Thus, apart from continued long-term monitoring of agricultural insect pests and the development of diversified prevention and control methods, there is a need to protect the diversity of non-pest and beneficial migratory insects.