Climate change is expected to alter the spatial distribution of forest-associated insects, yet responses may vary among closely related species. We used an ensemble species distribution modeling framework to project current and future potential suitable areas for 5 Coraebus species (Coraebus acutus, C. cloueti, C. diminutus, C. quadriundulatus, and C. sauteri) in China under four Shared Socioeconomic Pathways (SSP126, SSP245, SSP370, and SSP585). Under current climatic conditions, suitable habitats were primarily concentrated in southeastern China, with species-specific differences in highly suitable areas. Future projections revealed scenario-dependent redistribution patterns. While total suitable areas showed moderate overall change, centroid migration displayed stage-specific displacement peaks, particularly under higher-emission scenarios. Temperature-related variables, especially indices describing thermal variability and extremes, consistently ranked among the most influential predictors, indicating that seasonal constraints play a central role in shaping distribution dynamics. Interspecific heterogeneity was evident, with species differing in both migration magnitude and temporal response patterns. Redistribution did not proceed linearly through time but exhibited mid-to-late-century intensification under certain emission pathways, suggesting potential threshold responses to climatic forcing. These findings highlight that climate-driven redistribution of wood-boring beetles may be species-specific and temporally variable. Incorporating multiple emission scenarios and species-level assessments can improve monitoring strategies and support adaptive forest management under changing climatic conditions.

The assembly of insect mitochondrial genomes remains challenging in certain taxa due to extreme AT biases and long repetitive regions. The family Diaspididae (Hemiptera: Coccomorpha) exemplifies this difficulty; despite more than 2,700 described species worldwide, no complete mitogenome has been reported prior to this study. Here, the complete mitogenome is presented of Aulacaspis yasumatsui, assembled using a hybrid approach combining second- and third-generation sequencing platforms. The A. yasumatsui mitogenome is the longest identified to date among scale insects, spanning 21,273 bp. It exhibits several extraordinary features, most notably the highest AT content (92%) yet recorded in Insecta, extensive gene rearrangements, the absence of half of the tRNA genes, and the first identified ultra-long repeat region (> 5,000 bp) in Coccomorpha. The leg degeneration and loss observed in Diaspididae evolution may have contributed to the emergence of such an extreme mitogenome structure. Comparative analysis of sequencing strategies revealed substantial coverage bias in Illumina data, which was effectively mitigated by Oxford Nanopore long reads. We propose a standardized pipeline tailored for efficient and accurate assembly of highly AT-rich and structurally complex mitogenomes. This study provides both methodological insights and a valuable genomic resource for future evolutionary and comparative studies on Diaspididae and other taxa with challenging mitogenomes.

Aphis aurantii (Hemiptera: Aphididae) is a polyphagous insect pest that inflicts significant damage to diverse host plants, particularly within the Theaceae and Rutaceae, and transmits plant viruses such as citrus tristeza virus (CTV). These impacts highlight the need for genomic resources to support research on host adaptation and pest management. Here, we present the first high-quality chromosome-level genome assembly of A. aurantii. The assembled genome spans 347.32 Mb with a contig N50 of 40.10 Mb, and BUSCO assessment revealed a high completeness score of 96.85%. Using Hi-C scaffolding, 340.64 Mb of the genome was anchored into four pseudochromosomes, achieving a scaffold N50 of 90.37 Mb. Additionally, we annotated 16,881 protein-coding genes. This genome provides a reference resource for future investigations of genetic variation, host plant interactions, and polyphagy in aphids.

ABSTRACT Symbiotic bacteria play a crucial role in the life history of insects. Aphids and their diverse symbiotic bacteria serve as an excellent model for studying the bacterial‐insect symbiotic relationship. Our recent study revealed that the aphid Periphyllus koelreuteriae, an important ornamental pest specifically feeding on Koelreuteria plants and widely distributed in the temperate and subtropical regions of China, is actually a species complex that includes three species (P. koelreuteriae, P. blackmani, and P. guangxuei). To characterize the composition and abundance of the symbiotic bacterial communities within this species complex, we employed Illumina NovaSeq high‐throughput sequencing to assess symbiotic bacterial diversity and further investigated the associations between symbiont community profiles and aphid species, geographic populations, and host plants. The results show that two dominant symbiotic bacteria were detected, namely Buchnera and Serratia. The mean relative abundance of Buchnera exhibited the trend: P. guangxuei (88.41%) < P. blackmani (95.36%) < P. koelreuteriae (98.51%), which are distributed in subtropical highland, subtropical humid, and temperate regions, respectively, whereas Serratia showed the opposite pattern. Redundancy analysis (RDA) revealed that latitude (LAT) and the minimum temperature of the coldest month (BIO6) are critical environmental factors affecting the composition of symbiotic bacteria in the P. koelreuteriae species complex. The relative abundance of Buchnera significantly decreased with decreasing latitude and increasing minimum temperature of the coldest month, whereas the relative abundance of Serratia exhibited the opposite. These results indicate that the composition and abundance of symbiotic bacteria in this species complex are influenced by both aphid species and geographic‐climatic conditions, with latitude (LAT) and the minimum temperature of the coldest month (BIO6) identified as key environmental factors shaping the community structure. This study elucidates the distribution patterns of symbiotic bacteria across closely allied aphid species and along environmental gradients, providing a theoretical foundation for understanding the ecological adaptation mechanisms of this aphid species complex and laying a scientific basis for developing targeted integrated management strategies in the future.

The Qinghai-Tibet Plateau-Himalaya region (QTP-Himalayas) is a global biodiversity hotspot that has been shaped by the evolution of complex topography and elevational gradients during Cenozoic collisional tectonics. In this paper, we analyze modern distribution patterns of Lepidoptera based on 70,661 records of 6099 species to infer aspects of palaeobiogeographic evolution. Results indicate that species richness is concentrated along the Himalayan margin. Through multivariate regressive and geographic random forest analyses, we identify water availability and habitat heterogeneity as the strongest predictors positively associated with modern species richness, whereas climate stability and historical climate change variables exerted significant negative impacts on species richness. Analyses of phylogenetic diversity patterns reveal pronounced spatial heterogeneity. The Hengduan Mountains exhibits a trend toward phylogenetic overdispersion and harbors a higher proportion of ancient Cretaceous-Paleogene lineages, highlighting this southeastern region of the QTP-Himalayas as a biodiversity “museum”. In contrast, the Pamir Plateau shows significant phylogenetic clustering dominated by relatively younger Neogene lineages, reflecting the role of this arid western area as a biodiversity “cradle”. The evolution of Lepidoptera diversity is therefore primarily regulated by the combined effects of climate stability and topographic heterogeneity. These findings are important for insect diversity conservation practices in the QTP-Himalayas region.

Arthropods play critical roles in forest ecosystems, contributing to pollination, nutrient cycling, and food web dynamics. With increasing global forest fragmentation, forest edges are expanding. Yet, the influence of edge effects on arthropod abundance and richness remains unclear. Using a hierarchical meta-analysis, we examined global patterns in arthropod abundance and richness between forest edges and interiors, and identified the key drivers of these differences. Based on 1472 abundance effects (73 studies) and 89 richness effects (33 studies), forest edges had 53.47% higher abundance and 14.34% greater richness than interiors. However, significant heterogeneity indicated considerable variation in effect sizes across studies. Among the seven moderating factors examined, edge contrast, flight ability, and diet significantly influenced the edge-interior difference in arthropod abundance, whereas flight ability, diet, and taxonomic order were significant for species richness. Edge contrast influenced abundance positively at low and medium contrast edges but negatively at high contrast edges. Flying arthropods exhibited a stronger preference for edges than crawling species, and plant-dependent taxa (e.g., phytophages, sap-suckers, and pollinivores/nectarivores) increased more in abundance and richness at edges. However, taxa dependent on stable microclimates (e.g., spiders) showed reduced abundance and richness at forest edges. These findings help clarify arthropod distribution patterns in fragmented forests and provide practical implications for forest conservation and integrated landscape management.

Hemipteran insects typically rely on lineage-specific bacterial symbionts to meet their nutritional needs. However, soft scales (Hemiptera: Coccidae) are unique, with fungal rather than bacterial dominant symbionts. While bacterial symbioses in Hemiptera have been widely studied, fungal symbionts remain poorly understood. In this study, we investigated the red wax scale Ceroplastes rubens, a major pest of ornamental plants, by analysing 260 samples collected from 47 locations across 14 provinces in China between 2010 and 2023. We sequenced mitochondrial COI and nuclear 28S genes of the host and ITS and EF-1 alpha genes of its fungal symbiont, Ophiocordyceps (Hypocreales, Ophiocordycipitaceae). Phylogenetic reconstruction revealed four geographically distinct lineages of C. rubens in southern China, shaped by biogeographic barriers, host plant variation, and historical climate patterns. Each lineage harboured a specific Ophiocordyceps clade, exhibiting strong phylogenetic congruence. Cophylogenetic analyses revealed a significant association between the host and its fungal symbiont, supporting the parallel evolution hypothesis. Divergence time estimates suggested that the Ophiocordyceps symbiont associated with C. rubens originated after its host and subsequently underwent codiversification. This study provides the most comprehensive phylogenetic framework to date for scale insects and their fungal symbionts, offering novel insights into the evolution of obligate symbioses in Hemiptera.

Inadequate research on polymorphism and functional adaptations of sensilla in social aphids hinders elucidation of the sensory basis underlying their caste differentiation and host specialization. This study employed scanning electron microscopy to investigate and compare the key sensilla traits on the sensory appendages across castes of the social aphid Pseudoregma bambucicola. Eight morphological types encompassing 16 subtypes of sensilla were identified. Antennae possess the most diverse sensilla, including 8 types and 11 subtypes. Five SB-1 sensilla are consistently distributed at the antennal apex. The ultimate rostral segment uniquely harbors ST-3, SB-2, and SB-3. AS are found exclusively along the subcostal vein of the forewings in alate females. Sch-1 is restricted to articular junctions. The first tarsomere bears CS, while SB-1 is present on the second tarsomere. Notably, the sensilla types differ between alate and apterous morphs. Statistical analysis also revealed significant differences in key functional sensilla traits across castes of P. bambucicola. Specifically, the abundance and length of ST-1, the volume of SB-1, and the area of RMPS differed significantly between the An/As and soldier/nymph caste pairs. The caste- and tissue-specific distribution and variation of sensilla traits in P. bambucicola may arise from the intrinsic biology, ecological adaptation, and distinct functional demands of each caste. This study provides a comprehensive map of sensilla types and distribution in a social aphid, establishing a morphological framework for future research on the communication of social information.

Aphids, as specialised, sap-sucking herbivores, pose a serious threat to plants, both in natural ecosystems and in agriculture. While their specialisation allows effective management, due to their ecological plasticity, any factors disturbing this specialisation may increase their harmfulness. Here we report unexpected exploitation of Capsicum (Magnoliopsida, Solanaceae) by the widely distributed black fern aphid Idiopterus nephrelepidis, previously recorded only on ferns (Polypodiopsida). Incidental observation of unusual host plant exploitation in household conditions demonstrated the remarkable ability of this aphid to alter its nutritional source. Analysis of plant structure demonstrated clear anatomical and chemical differences in both exploited hosts, without specialised structures or sensillary organs in the aphid mouthparts. Two alternative hypotheses explaining the observed host expansion are discussed: (1) In the wild, the black fern aphid exploits (or exploited) some Solanaceae species, possibly as the primary host, consequently retaining an ability to overcome the deterrent properties of pepper. (2) Feeding in an anthropogenic environment (e.g. greenhouse) may reduce the negative selective pressure of natural enemies, enabling aphids to feed on new plant species. In either case, the observed host expansion highlights the need to monitor the potential of this aphid to exploit crop plants.

Cuticular proteins (CPs) constitute the primary structural components of the insect cuticle and play crucial roles in cuticle formation. In the social aphid Pseudoregma bambucicola, sterile soldiers cease molting and evolve specialized defensive structures, including enlarged forelegs and elongated hindlegs, whereas normal nymphs lack these features. However, it remains unclear whether soldier caste-specific CPs are involved in regulating reproductive sterility, suppression of molting, and the formation of defensive leg structures. To explore this, we identified 89 CP genes in the P. bambucicola genome. Chromosomal mapping revealed multiple gene duplication events. Transcriptomic analysis demonstrated distinct temporal expression patterns of CP genes between soldiers and normal nymphs. Cluster II genes are associated with molting and development of normal nymphs, while soldiers exhibit the opposite pattern for these genes. Cluster I genes show transient expression at the early stage of post-embryonic development in soldiers, whereas Cluster III genes maintain stable expression levels throughout postnatal development. Among these, PbamCPR-54, a pro-resilin-like gene containing the RR-2 motif, exhibits upregulated expression from 2 to 72 h during post-embryonic development of soldiers, with the highest levels detected in hindleg tissues. To investigate its function, RNA interference (RNAi) knockdown of PbamCPR-54 was performed, resulting in deformities and bending of soldier hind tibiae. Eosin Y staining further revealed that gene silencing altered the structural integrity of hindleg cuticle. These findings provide novel insights into the roles of CP genes in caste-specific development and morphological differentiation in social insects.

Housekeeping and colony defense behaviors are crucial for social aphids, as they help maintain a habitable living environment and enhance their ecological adaptability. However, over the past decades, numerous studies have focused on housekeeping and colony defense behaviors in species living in primary hosts, but little attention has been given to the secondary host stage. This constrains a deeper understanding of the altruistic behavior of social aphids, as well as the ecological and evolutionary significance of such behavior. We employed indoor video recordings to document and analyze the behaviors displayed by the soldiers of the sugarcane wooly aphid, C. lanigera, on secondary hosts. C. lanigera soldiers continuously patrol around the colony to detect potential threats. When encountering potential threats or obstacles, soldiers actively initiate cleaning behavior. The soldiers use their frontal horns to disengage the hardened honeydew, corpses, or honeydew simulants (rock sugar) that are attached to the surface of host plant leaves. Subsequently, they transport these materials away from the colony using their frontal horns or forelegs, either discarding or flicking them directly. When soldiers identify obstacles—such as predator eggshells—as natural enemies, they attack them with their frontal horns. Our findings contribute to a broader understanding of altruistic behavior in social aphids and the evolutionary success of their sociality.

Phosphorus (P), a non-renewable resource essential for sustaining life, faces increasing environmental losses from agricultural systems. However, the effects of flavonoid-induced iron oxide on soil P behavior remain poorly understood, particularly in paddy soils. Here, we conducted a 7-year field trial under four fertilization regimes combined with laboratory incubations to reveal how flavonoid-modified iron oxides regulate P at the molecular scale. Results showed that manure-applied (NPKM) soils increased the content of flavonoids by 48.7% and short-range-order minerals (SROs) by 8.7% compared with chemically fertilized (NPK) soils. Through interfacial reactions between Fe-P minerals and quercetin, the formation of 2-line ferrihydrite was promoted by quercetin with an interplanar distance of 0.26/0.30 nm at pH 7. It was found that 14.25% of the Fe-phosphate group was incorporated at a quercetin concentration of 1 mM, and Fe oxides acted as the "core" for retaining P in these complexes. Further, phosphate release was observed during the interfacial reaction with increasing quercetin concentrations, suggesting a potential trade-off between P fixation and release. Despite these benefits, NPKM soils exhibited the highest degree of phosphorus saturation (DPS) (18.61%) and the lowest soil phosphorus storage capacity (1.70 mg kg-1), indicating an elevated risk of P loss. A significant positive correlation was identified among SROs, flavonoids, and DPS in paddy soils. Collectively, our findings demonstrate that flavonoids can modify the morphology of Fe oxides in paddy soils, thereby enhancing P fixation. This presents a promising approach for mitigating diffuse P pollution and promoting sustainable agriculture.

Scale insects (Hemiptera: Coccoidea), comprising archaeococcoids and neococcoids, represent the fourth largest superfamily within the order Hemiptera and are recognized as significant agricultural and forestry pests. Despite the increasing availability of insect genomic data, systematic phylogenetic studies of scale insects at the family level have been limited due to challenges in specimen collection, identification, and sequencing. In this study, we sequenced the genomes of 46 species representing 20 families and integrated this data with publicly available sequences to encompass 22 families, representing 95% of Coccoidea taxa. Notably, 14 of these families are sequenced for the first time. This work establishes a robust phylogenetic framework for scale insects. Our findings clarified the phylogenetic relationships of archaeococcoids, confirming Matsucoccidae as the most primitive extant group of scale insects and identifying Putoidae as a transitional lineage between archaeococcoids and neococcoids. We further demonstrated that Xenococcidae belongs to the neococcoids, distinct from Pseudococcidae, and revealed that Coccidae form a paraphyletic group, with Aclerdidae nested within Coccidae. Using MCMCTree analysis, we estimated the divergence times of various Coccoidea families and proposed a comprehensive evolutionary framework for scale insects. This study addresses key gaps in the phylogenetic and evolutionary understanding of Coccoidea, providing a valuable genomic resource and advancing our knowledge of their phylogeny and evolutionary history.

Nuclear receptors (NRs) constitute a superfamily of transcription factors that regulate diverse biological processes. In insects, NRs not only govern essential physiological functions including metabolism, development, and reproduction, but also play pivotal roles in regulating caste differentiation and division of labor within social insect colonies. Pseudoregma bambucicola is a species of social aphid in which adults exhibit a specialized reproductive division of labor. This unique system produces first-instar nymphs and soldiers, which share an identical genetic background yet exhibit distinct morphological and behavioral traits. Although NRs exhibit pleiotropic regulatory capacities, their roles in the unique developmental patterns of P. bambucicola remain unclear. This study identified 21 NR genes based on the genomic data of P. bambucicola and analyzed the duplication and loss events of these genes through phylogenetic analysis. Additionally, differential expression of NR genes was analyzed using transcriptomic data. The TLL exhibited significant differential expression in adults with distinct reproductive behaviors, suggesting its involvement in the regulation of reproductive division of labor. E75 and HNF4 were found to be important for the post-embryonic development of soldiers. Furthermore, quantitative real-time PCR confirmed caste-specific expression patterns of HR4 and HR39, indicating their potential involvement in morphological differentiation and developmental regulation among castes. This study conducted bioinformatic identification of NR genes in the social aphid P. bambucicola, and investigated their potential roles in morphological differentiation and behavioral division through analysis of differential gene expression. The findings provide preliminary evidence for the functional significance of NR genes in social aphids, while offering novel insights for subsequent research exploration.

Two new species of Baetis s. l. are described and illustrated based on nymphal materials. Baetis chongqingensis sp. nov. is characterized by the elongated labrum, the presence of stout setae on scape, the absence of apical scale on segment II of maxillary palp, the well-developed projection on segment II of labial palp, and the absence of chagrin and spatulate setae on abdominal terga. Baetis (Rhodobaetis) qianlei sp. nov. can be differentiated from the other species of subgenus Rhodobaetis by the number of spatulate setae on the scape and pedicel, the shape of labial palp and tergalii, and the length of paracercus.

Most phloem-feeding insects face nutritional deficiency and rely on their intracellular symbionts to provide nutrients, and most of endosymbiont genomes have undergone reduction. However, the study of genome reduction processes of endosymbionts has been constrained by the limited availability of genome data from different insect lineages. The obligate relationship between aphids and Buchnera aphidicola (hereafter Buchnera) makes them a classic model for studying insect-endosymbiont interaction. Here, we report 29 newly sequenced Buchnera genomes from 11 aphid subfamilies, and a comprehensive dataset based on 90 Buchnera genomes from 14 aphid subfamilies. The dataset shows a significant genomic difference of Buchnera among different aphid lineages. The dataset exhibits a more balanced distribution of Buchnera (from 14 aphid subfamilies) genome sizes, ranging from 400 kb to 600 kb, which can illustrate the genome reduction process of Buchnera. The new genome data provide valuable insights into the microevolutionary processes leading to genomic reduction of insect endosymbionts.

The diversity and health of insects that feed on plants are closely related to their mutualistic symbionts and host plants. These symbiotic partners significantly influence various metabolic activities in these insects. However, the symbiotic bacterial community of toxic plant feeders still needs further characterisation. This study aims to unravel bacterial communities associated with the different species of insect representing three insect orders: Thysanoptera, Hemiptera, and Lepidoptera, along with their predicted functional role, which exclusively feeds on latex-rich plant species Ficus microcarpa. By using 16S rRNA gene high-throughput sequencing, the analysis was able to define the major alignment of the bacterial population, primarily comprising Proteobacteria, Firmicutes, Bacteroidota, Actinobacteriota, and Acidobacteriota. Significant differences in symbiotic organisms between three insect groups were discovered by the study: hemipterans had Burkholderia and Buchnera, and lepidopterans had Acinetobacter. At the same time, Pseudomonas was detected in high abundance in both lepidopteran and thysanopteran insects. Furthermore, these symbionts exhibit consistent core functions, potentially explaining how different insects can consume the same host plant. The identified core functions of symbionts open avenues for innovative approaches in utilising these relationships to develop environment-friendly solutions for pest control, with broader implications for agriculture and environmental conservation.

The health and diversity of plant-feeding insects are strictly linked to their host plants and mutualistic symbionts. However, the study of bacterial symbionts within different insects on the same plant lineage is very limited. This study aimed to investigate the bacterial diversity in insect samples that exclusively feed on Bambusa, representing three insect orders, Hemiptera, Lepidoptera, and Blattodea, each exhibiting distinct dietary preferences. The bacterial community was predominantly composed of Proteobacteria, Spirochaetota, Cyanobacteria, Firmicutes, and Bacteroidota. The study found significant variations in symbiotic organisms among three insect orders: hemipterans had Buchnera, lepidopterans had Acinetobacter, and blattodean had Treponema. Furthermore, the dietary preferences of these insects played a pivotal role in shaping the symbiotic relationship of insects. Proteobacteria are prevalent in sap feeders, Spirochaetota dominate in stem feeders, and Cyanobacteria are abundant in leaf feeders. Seasonal influences also affect bacterial symbionts in P. bambucicola, with Serratia present exclusively in winter. We also observed that the bacterial composition varies across all samples, but their core functions appear to be consistent. This highlights the complex relationship between host phylogeny and diet, with phylogeny being the primary driver, shaping adaptations to specialized diets.

Host plants play a vital role in insect population differentiation, while symbiotic associations between bacteria and insects are ubiquitous in nature. However, existing studies have given limited attention to the connection between host-related differentiation and symbiotic bacterial communities in phytophagous insects. In this study, we collected 58 samples of Aphis odinae from different host plants in southern China and constructed phylogenetic trees to investigate their differentiation in relation to host plants. We also selected aphid samples from the five most preferred host plants and analyzed their symbiotic bacterial composition using Illumina sequencing of the V3–V4 hypervariable region of the 16S rRNA gene. The phylogeny and symbiotic bacterial community structure of A. odinae populations on different host plants showed that samples from Triadica sebifera (Euphorbiaceae) had a consistent presence of Wolbachia as the predominant secondary symbiont and suggested the possibility of undergoing differentiation. Conversely, although differentiation was observed in samples from Rhus chinensis (Anacardiaceae), no consistent presence of predominant secondary symbionts was found. Additionally, the samples from Heptapleurum heptaphyllum (Araliaceae) consistently carried Serratia, but no host differentiation was evident. In summary, this study reveals a partial correspondence between symbiotic bacterial communities and host-related differentiation in A. odinae. The findings contribute to our understanding of the microevolutionary influencing the macroevolutionary relationships between bacterial symbionts and phytophagous insects. The identification of specific symbionts associated with host-related differentiation provides valuable insights into the intricate dynamics of insect-bacteria interactions.

The rapid advancement of high-throughput sequencing has led to a great increase in sequencing data, resulting in a significant accumulation of contamination, for example, sequences from non-target species may be present in the target species’ sequencing data. Insecta, the most diverse group within Arthropoda, still lacks a comprehensive evaluation of contamination prevalence in public databases and an analysis of potential contamination causes. In this study, COI barcodes were used to investigate contamination from insects and mammals in GenBank’s genomic and transcriptomic data across four insect orders. Among the 2796 WGS and 1382 TSA assemblies analyzed, contamination was detected in 32 (1.14%) WGS and 152 (11.0%) TSA assemblies. Key findings from this study include the following: (1) TSA data exhibited more severe contamination than WGS data; (2) contamination levels varied significantly among the four orders, with Hemiptera showing 9.22%, Coleoptera 3.48%, Hymenoptera 7.66%, and Diptera 1.89% contamination rates; (3) possible causes of contamination, such as food, parasitism, sample collection, and cross-contamination, were analyzed. Overall, this study proposes a workflow for checking the existence of contamination in WGS and TSA data and some suggestions to mitigate it.