Insects

19 pages, 1118 KB

Open AccessArticle

Phylogeographic Insights into Aedes albopictus in Korea: Integrating COX1, ND5, and CYTB Analyses

by Sezim Monoldorova, Jong-Uk Jeong, Sungkyeong Lee, Ilia Titov, In-Yong Lee, Hojong Jun, Jin-Hee Han, Fauzi Muh, Kwang-Jun Lee and Bo-Young Jeon

Insects 2026, 17(1), 82; https://doi.org/10.3390/insects17010082 (registering DOI) - 10 Jan 2026

Abstract

The Asian tiger mosquito (Aedes albopictus) is an important vector of arboviruses, including dengue, chikungunya, and Zika. Its rapid global expansion has been facilitated by climate change and human activities. Phylogenetic studies of Ae. albopictus have largely relied on mitochondrial [...] Read more.

The Asian tiger mosquito (Aedes albopictus) is an important vector of arboviruses, including dengue, chikungunya, and Zika. Its rapid global expansion has been facilitated by climate change and human activities. Phylogenetic studies of Ae. albopictus have largely relied on mitochondrial cytochrome c oxidase subunit 1 (COX1) and NADH dehydrogenase subunit 5 (ND5) markers, while the utility of cytochrome b (CYTB) remains underexplored. We collected Ae. albopictus from 13 sites in seven provinces of South Korea and analyzed COX1, ND5, and CYTB sequences. Genetic diversity indices were calculated, and phylogenetic relationships were reconstructed using maximum-likelihood trees and haplotype networks with a dataset obtained from GenBank. COX1 revealed 46 haplotypes, including six novel variants, with the highest diversity in southern coastal regions such as Busan and Suncheon. ND5 showed limited variation, with only two haplotypes. CYTB revealed three haplotypes, including region-specific variants in Busan and Wonju, supporting its role as a complementary marker. The Busan haplotype H41 bridged domestic and international lineages, suggesting Busan as a likely entry point. This study demonstrates that integrating COX1, ND5, and CYTB improves the resolution of Ae. albopictus phylogeography in Korea and highlights the need for continued molecular surveillance to guide vector control strategies. Full article

(This article belongs to the Special Issue Challenges in Mosquito Surveillance and Control)

17 pages, 37724 KB

Open AccessArticle

Multi-Condition Cultivation Reveals the Host Plant-Dependent Gut Bacteria Diversity in Tomato Leafminer (Tuta absoluta) Larvae

by Xiaoyu Fang, Ruoyi Wen, Liyan Yang, Jianyang Guo, Wenjun Shen, Nianwan Yang, Fanghao Wan, Zhichuang Lü and Wanxue Liu

Insects 2026, 17(1), 81; https://doi.org/10.3390/insects17010081 (registering DOI) - 10 Jan 2026

Abstract

Tomato leafminer (Tuta absoluta) significantly affects tomato (Solanum lycopersicum) and eggplant (Solanum melongena) crops worldwide, with its feeding patterns being closely associated with its gut microbiota. We aimed to compare the cultivable gut bacteria of T. absoluta [...] Read more.

Tomato leafminer (Tuta absoluta) significantly affects tomato (Solanum lycopersicum) and eggplant (Solanum melongena) crops worldwide, with its feeding patterns being closely associated with its gut microbiota. We aimed to compare the cultivable gut bacteria of T. absoluta larvae fed on tomato and eggplant to investigate their role in host adaptation. Gut bacteria were cultivated on Luria–Bertani broth, nutrient agar, and Brain Heart Infusion media under different temperature conditions, followed by morphology- and 16S rRNA-based identification. Notably, both feeding groups revealed distinct gut bacterial community structures. Tomato-fed larvae harbored bacteria spanning eight species, five genera, four families, and two phyla. In contrast, eggplant-fed larvae exhibited greater microbial diversity, encompassing 15 species, 10 genera, 9 families, and 3 phyla, including unique genera such as Pseudomonas and Pectobacterium, which was attributed to the host plant contribution. Enterococcus mundtii was the most dominant bacterium, and species such as Bacillus wiedmannii and Micrococcus luteus were most thermotolerant. Overall, these findings highlight the importance of multi-condition culture approaches for thoroughly characterizing insect gut microbiota and underscore the role of host plants in pest adaptability by modulating gut microbial communities, providing new insights for developing sustainable control strategies utilizing “plant–insect–microorganism” interactions. Full article

(This article belongs to the Section Insect Physiology, Reproduction and Development)

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13 pages, 4101 KB

Open AccessArticle

Transcriptome Dynamics of BmN Cells During the Early Phase of Bombyx mori Nucleopolyhedrovirus Infection

by Xiong Wang, Fangyu Miao, Wei Wang, Jingchen Sun and Lunguang Yao

Insects 2026, 17(1), 80; https://doi.org/10.3390/insects17010080 - 9 Jan 2026

Abstract

The silkworm, Bombyx mori, is an economically important insect severely impacted by Bombyx mori nucleopolyhedrovirus (BmNPV), a double-stranded DNA virus that causes substantial losses to the sericulture industry. To elucidate the mechanisms of BmNPV infection and replication, we performed transcriptome sequencing of [...] Read more.

The silkworm, Bombyx mori, is an economically important insect severely impacted by Bombyx mori nucleopolyhedrovirus (BmNPV), a double-stranded DNA virus that causes substantial losses to the sericulture industry. To elucidate the mechanisms of BmNPV infection and replication, we performed transcriptome sequencing of BmN cells infected with a recombinant BmNPV at 12 and 24 h post infection (hpi). A total of 1136 differentially expressed genes (DEGs) were identified in the 12 hpi group, including 789 up-regulated and 347 down-regulated genes, while 5191 DEGs were detected at 24 hpi, including 2102 up-regulated and 3089 down-regulated genes. Functional annotation via GO and KEGG analyses highlighted the ECM–receptor interaction pathway as particularly significant. Furthermore, RT-qPCR results demonstrated that Map3k12 inhibits BmNPV replication. These findings lay the groundwork for further investigation into the molecular mechanisms of BmNPV infection and can be utilized for breeding dominant genes conferring resistance to nucleopolyhedrovirus in the silkworm. Full article

(This article belongs to the Section Insect Behavior and Pathology)

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16 pages, 1339 KB

Open AccessArticle

Comparative Analysis of the Gut Bacterial Community in Laboratory-Reared and Seasonally Field-Released Larvae of the Antheraea pernyi

by Peng Hou, Li Liu, Ding Yang, Chuntian Zhang and Jianfeng Wang

Insects 2026, 17(1), 79; https://doi.org/10.3390/insects17010079 - 9 Jan 2026

Abstract

Analyzing the composition and structure of the gut bacterial community in Antheraea pernyi is essential for improving its economic traits, as well as for understanding gut bacteria–host interactions in lepidopteran insects. This study utilized the Illumina MiSeq PE 300 platform to conduct 16S [...] Read more.

Analyzing the composition and structure of the gut bacterial community in Antheraea pernyi is essential for improving its economic traits, as well as for understanding gut bacteria–host interactions in lepidopteran insects. This study utilized the Illumina MiSeq PE 300 platform to conduct 16S rRNA gene sequencing for a comparative analysis of gut bacterial community in laboratory-reared and field-released (spring and autumn) Antheraea pernyi larvae of the same strain. The study revealed the specific effects of rearing environment and seasonal variation on the structural and functional dynamics of the larval gut bacterial communities. The composition of the dominant gut bacteria varied significantly with rearing environment and season. Laboratory-reared and spring field-released groups exhibited similar bacterial community structures, whereas the autumn field-released group showed a significant trend toward specialization, characterized by enrichment of specific bacterial taxa. Linear discriminant analysis effect size identified statistically significant biomarkers across samples. Taxonomic analysis revealed that Actinomycetota, Actinobacteria, Mycobacteriales, Dietziaceae, and Dietzia were characteristic of the gut bacteria profile in spring field-released, Lactobacillales, Enterococcaceae, and Enterococcus were enriched in the autumn field-released group, and the laboratory-reared group exhibited a relative dominance of Alphaproteobacteria. Functional prediction indicated that gut bacterial community structure likely influences its metabolic potential, which may suggest an adaptive response of the Antheraea pernyi to distinct ecological environments. This study provides important insights into the highly complex nature of insect-microbe interactions. Full article

(This article belongs to the Section Insect Physiology, Reproduction and Development)

15 pages, 3928 KB

Open AccessArticle

Integrative Taxonomy Clarifies Species Limits in Two Closely Related Solitary Wasps: Pachymenes ater and Pachymenes ghilianii (Hymenoptera: Vespidae: Eumeninae)

by Wellington Ferreira, Rodolpho Menezes, Matheus Viana and Marcel Hermes

Insects 2026, 17(1), 78; https://doi.org/10.3390/insects17010078 - 9 Jan 2026

Abstract

Species delimitation in morphologically conserved groups poses a significant challenge for traditional taxonomy. In the Neotropical wasp genus Pachymenes (Hymenoptera: Vespidae: Eumeninae), two putative sister species—Pachymenes ater and P. ghilianii—have historically been distinguished by a limited set of ambiguous morphological characters, [...] Read more.

Species delimitation in morphologically conserved groups poses a significant challenge for traditional taxonomy. In the Neotropical wasp genus Pachymenes (Hymenoptera: Vespidae: Eumeninae), two putative sister species—Pachymenes ater and P. ghilianii—have historically been distinguished by a limited set of ambiguous morphological characters, often complicated by intraspecific variation and overlapping geographic distributions. Here, we apply an integrative taxonomic framework combining morphological, molecular, and geographic evidence to test species limits between these two taxa. We reassess previously proposed diagnostic traits and explore the utility of additional characters across multiple lines of evidence. Our results indicate that some morphological characters traditionally used for identification are insufficient for clear separation of species, while other, previously overlooked traits offer improved resolution. Molecular data further support species distinction and provide new insights into the evolutionary relationship between P. ater and P. ghilianii. This study highlights the importance of combining diverse data sources for robust species delimitation in solitary wasps and contributes to a better understanding of species boundaries within Eumeninae. Full article

(This article belongs to the Section Insect Systematics, Phylogeny and Evolution)

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22 pages, 2983 KB

Open AccessArticle

Predicting Phloeosinus cupressi (Coleoptera: Curculionidae: Phloeosinus) Distribution for Management Planning Under Climate Change

by Yu Cao, Kaitong Xiao, Lei Ling, Qiang Wu, Beibei Huang, Xiaosu Deng, Yingxuan Cao, Hang Ning and Hui Chen

Insects 2026, 17(1), 77; https://doi.org/10.3390/insects17010077 - 9 Jan 2026

Abstract

Phloeosinus cupressi Hopkins is an invasive bark beetle that poses a serious threat to Cupressus trees, with potential ecological and economic impacts globally. Native to North America, it has spread to Australia and New Zealand, and climate change may further alter its range. [...] Read more.

Phloeosinus cupressi Hopkins is an invasive bark beetle that poses a serious threat to Cupressus trees, with potential ecological and economic impacts globally. Native to North America, it has spread to Australia and New Zealand, and climate change may further alter its range. Global trade increases the risk of spread, highlighting the need for predictive modeling in management. In this study, we employed CLIMEX and random forest (RF) models to project the potential global distribution of P. cupressi, incorporating host distribution data for Cupressus. Climatic suitability is concentrated in temperate, subtropical, and Mediterranean zones, including Europe, the U.S., South America, China, Australia, and New Zealand, totaling 10,165.22 × 10⁴ km². Coldest-quarter precipitation (bio19) and annual temperature range (bio7) were identified as the most influential variables. Under RCP6.0 scenarios, suitable areas are projected to expand northward, increasing by ~18%. Regional shifts include contraction in southern Europe and South China, expansion in southern Argentina, southeastern Australia, and coastal New Zealand. Temperature sensitivity is expected to exceed precipitation, enhancing colonization. Due to global Cupressus trade, quarantine and monitoring should focus on high-risk regions. Our findings support early detection, long-term monitoring, and control measures for managing P. cupressi under climate change. Full article

(This article belongs to the Special Issue Global and Regional Patterns of Insect Biodiversity)

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12 pages, 2095 KB

Open AccessArticle

Caste-Dependent Interspecific Tolerance Permits Alien Reproductives to Reproduce Within Host Colonies in Reticulitermes Termites Under Laboratory Conditions

by Zhuang-Dong Bai, Ya-Nan Dong, David Sillam-Dussès and Rui-Wu Wang

Insects 2026, 17(1), 76; https://doi.org/10.3390/insects17010076 - 9 Jan 2026

Abstract

Nestmate recognition is the primary defense mechanism maintaining the integrity of eusocial insect colonies. While social parasitism is widespread in Hymenoptera, it is rarely documented in termites, and the behavioral boundaries preventing interspecific infiltration remain poorly understood. Here, we investigated the potential for [...] Read more.

Nestmate recognition is the primary defense mechanism maintaining the integrity of eusocial insect colonies. While social parasitism is widespread in Hymenoptera, it is rarely documented in termites, and the behavioral boundaries preventing interspecific infiltration remain poorly understood. Here, we investigated the potential for interspecific integration between two closely related termite species under laboratory conditions. We introduced Reticulitermes labralis workers and reproductives (queens and kings) into orphaned groups of R. aculabialis. We found that host workers exhibited caste-dependent aggression: introduced workers were immediately attacked and eliminated, whereas alien reproductives were partially tolerated. Surviving alien reproductives successfully integrated into host group, receiving allogrooming and trophallactic care from host workers. Crucially, these integrated pairs produced viable eggs and larvae. Molecular analysis confirmed that the brood reared by the host workers were the genetic offspring of the introduced R. labralis pair, demonstrating successful “cuckoo-like” reproduction. These findings reveal that termite colony recognition is sufficiently flexible to permit the acceptance of heterospecific reproductives when native royals are absent. While field evidence remains to be discovered, our results demonstrate that the behavioral and physiological prerequisites for social parasitism exist in termites, supporting the hypothesis that close phylogenetic relatedness (Emery’s rule) facilitates the breach of social barriers. Full article

(This article belongs to the Section Social Insects and Apiculture)

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5 pages, 172 KB

Open AccessEditorial

Special Issue “Women’s Special Issue Series: Insects”

by Carmen Scieuzo, Rosanna Salvia and Patrizia Falabella

Insects 2026, 17(1), 75; https://doi.org/10.3390/insects17010075 - 9 Jan 2026

Abstract

The scientific community has long recognized that diversity drives innovation, creativity, and progress [...] Full article

(This article belongs to the Special Issue Women’s Special Issue Series: Insects)

25 pages, 2831 KB

Open AccessArticle

Lightweight Vision–Transformer Network for Early Insect Pest Identification in Greenhouse Agricultural Environments

by Wenjie Hong, Shaozu Ling, Pinrui Zhu, Zihao Wang, Ruixiang Zhao, Yunpeng Liu and Min Dong

Insects 2026, 17(1), 74; https://doi.org/10.3390/insects17010074 - 8 Jan 2026

Abstract

This study addresses the challenges of early recognition of fruit and vegetable diseases and pests in facility horticultural greenhouses and the difficulty of real-time deployment on edge devices, and proposes a lightweight cross-scale intelligent recognition network, Light-HortiNet, designed to achieve a balance between [...] Read more.

This study addresses the challenges of early recognition of fruit and vegetable diseases and pests in facility horticultural greenhouses and the difficulty of real-time deployment on edge devices, and proposes a lightweight cross-scale intelligent recognition network, Light-HortiNet, designed to achieve a balance between high accuracy and high efficiency for automated greenhouse pest and disease detection. The method is built upon a lightweight Mobile-Transformer backbone and integrates a cross-scale lightweight attention mechanism, a small-object enhancement branch, and an alternative block distillation strategy, thereby effectively improving robustness and stability under complex illumination, high-humidity environments, and small-scale target scenarios. Systematic experimental evaluations were conducted on a greenhouse pest and disease dataset covering crops such as tomato, cucumber, strawberry, and pepper. The results demonstrate significant advantages in detection performance, with mAP@50 reaching

0.872

, mAP@50:95 reaching

0.561

, classification accuracy reaching

0.894

, precision reaching

0.886

, recall reaching

0.879

, and F1-score reaching

0.882

, substantially outperforming mainstream lightweight models such as YOLOv8n, YOLOv11n, MobileNetV3, and Tiny-DETR. In terms of small-object recognition capability, the model achieved an mAP-small of

0.536

and a recall-small of

0.589

, markedly enhancing detection stability for micro pests such as whiteflies and thrips as well as early-stage disease lesions. In addition, real-time inference performance exceeding 20 FPS was achieved on edge platforms such as Jetson Nano, demonstrating favorable deployment adaptability. Full article

(This article belongs to the Special Issue Artificial Intelligence (AI) and Insect Pests Management: Securing Food Security, Human Health, and Natural Resources)

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16 pages, 1003 KB

Open AccessArticle

Direct and Indirect Effects of a Glyphosate-Based Herbicide on Spodoptera frugiperda Multiple Nucleopolyhedrovirus (Baculoviridae) on Diet, Maize Plants and Soil

by Juan S. Gómez-Díaz, Arely Y. Cubas, Mara J. Arias-Robledo and Trevor Williams

Insects 2026, 17(1), 73; https://doi.org/10.3390/insects17010073 - 8 Jan 2026

Abstract

Glyphosate is a broad-spectrum, systemic herbicide that has attracted concern over its non-target effects, environmental persistence, and the presence of residues in food. The fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), is a major invasive pest of maize that can be controlled by application [...] Read more.

Glyphosate is a broad-spectrum, systemic herbicide that has attracted concern over its non-target effects, environmental persistence, and the presence of residues in food. The fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), is a major invasive pest of maize that can be controlled by application of its homologous nucleopolyhedrovirus (SfMNPV), an occluded virus in the family Baculoviridae. We examined the effects of a glyphosate-based herbicide on S. frugiperda growth and survival and on virus occlusion bodies (OBs) exposed to product label-recommended concentrations of the herbicide. Larval growth, time to pupation, pupal weight, duration of the pupal stage and sex ratio were not affected by exposure to the herbicide (1% v/v solution) applied to the surface of semi-synthetic diet. Exposure to 1–2% herbicide solution had no effect on the median lethal concentration (LC₅₀) of OBs, the susceptibility of second instar larvae to virus infection, or the production of OBs in virus-killed larvae. Virus acquisition did not vary significantly when larvae fed on virus-sprayed maize plants at 1 and 6 days after they had been treated with herbicide, compared to healthy plants. Finally, the presence of 2% herbicide solution did not influence the persistence of OBs in non-sterilized soil samples over a 6-week greenhouse experiment. Although the laboratory and greenhouse experiments indicated that the glyphosate-based herbicide tested was unlikely to influence the transmission or persistence of SfMNPV OBs, future studies should verify these findings across a range of field conditions, soil types and different herbicide formulations. Full article

(This article belongs to the Special Issue The 15th Anniversary of Insects—Advances in Insect Pest and Vector Management)

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12 pages, 2455 KB

Open AccessArticle

Study on the Stability of Reference Genes and HSP60 for Expression Analysis in Chilo suppressalis in Response to Humidity Stress

by Ming Zhao, Yong Chen, Hai-Bo Zhang, Jian-Fei Mei and Ya-Jun Guo

Insects 2026, 17(1), 72; https://doi.org/10.3390/insects17010072 - 7 Jan 2026

Abstract

Quantitative real-time PCR (qRT-PCR) is a high-reliability, -sensitivity, and -operability technique to quantify gene expression. It is necessary to select stable reference genes for normalization. Water plays important roles in the metabolism, physiology, distribution, and so on, in insects. In this study, the [...] Read more.

Quantitative real-time PCR (qRT-PCR) is a high-reliability, -sensitivity, and -operability technique to quantify gene expression. It is necessary to select stable reference genes for normalization. Water plays important roles in the metabolism, physiology, distribution, and so on, in insects. In this study, the suitability of various reference genes for qRT-PCR analysis was evaluated in different developmental stages of Chilo suppressalis exposed to desiccation or rehydration stress. The ∆Ct method, geNorm, NormFinder, and BestKeeper were used to evaluate the suitability of nine reference genes for normalizing gene expression in the third instar larvae, the fifth instar larvae, male pupae, female pupae, male adults, and female adults under different humidities. The results indicated that 18S rRNA was the most stable reference gene for monitoring gene expression in the third instar larvae, while ACTIN, TUB, UBI, UBI, and EF1 were the optimal genes for the fifth instar larvae, male pupae, female pupae, male adults, and female adults, respectively. The optimal number of reference genes recommended by geNorm analysis indicated that two candidate reference genes were sufficient for data normalization under all experimental conditions tested. To validate these recommendations, the expression profile of the gene encoding heat shock protein 60 (Hsp60) was investigated. Hsp60 transcript levels showed significant differences when normalized to the most stable single reference gene, or combined reference genes, compared with the least stable reference gene. The reference genes identified in the present study will enhance the reliability of gene expression data for C. suppressalis under humidity stress. Full article

(This article belongs to the Special Issue Insects Ecology and Biological Control Applications)

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12 pages, 1182 KB

Open AccessArticle

Endosymbiont Infections in Korean Insects: Patterns Across Orders and Habitat Types

by Jae-Yeon Kang, Gilsang Jeong, In Jung An, Kihyun Kim, Se-hwan Son and Soyeon Park

Insects 2026, 17(1), 71; https://doi.org/10.3390/insects17010071 - 7 Jan 2026

Abstract

Endosymbiotic bacteria influence the ecology and evolution of insects through complex associations within host cells. To explore how these relationships vary among environments and taxa, we examined 1028 insect specimens from 14 orders across Korea for infections by three representative endosymbionts (Wolbachia [...] Read more.

Endosymbiotic bacteria influence the ecology and evolution of insects through complex associations within host cells. To explore how these relationships vary among environments and taxa, we examined 1028 insect specimens from 14 orders across Korea for infections by three representative endosymbionts (Wolbachia, Rickettsia, and Spiroplasma). Overall, 33.8% of specimens were infected, with single infections predominating and co-infections remaining relatively less common. Weak-to-modest but statistically significant associations were detected between several symbiont pairs (Rickettsia–Spiroplasma, Wolbachia–Spiroplasma, and Wolbachia–Rickettsia). Infection rates exhibited no significant variation among host orders except for Spiroplasma, and Wolbachia infections were more frequently detected in terrestrial than in aquatic insects. These results indicate that endosymbiont infection patterns might be shaped by factors operating at multiple biological scales, including host taxonomy and habitat types. As this study relied on polymerase chain reaction detection, infection frequencies should be interpreted as comparative rather than absolute measures. This survey provides baseline data that might help characterize regional patterns of endosymbiont distributions and their variation across taxonomic and ecological contexts. Full article

(This article belongs to the Special Issue Insect Microbiome and Immunity—2nd Edition)

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14 pages, 889 KB

Open AccessReview

Genomic Insights and Bioconversion Potential in the Black Soldier Fly (Hermetia illucens): Current Advances and Future Directions

by Joana Oliveira, Leonardo Gaston Guilgur, Ricardo Assunção, Daniel Murta and Alexandre Trindade

Insects 2026, 17(1), 70; https://doi.org/10.3390/insects17010070 - 7 Jan 2026

Abstract

The global population continues to rise, placing increasing pressure on the agri-food sector and leading to the accelerated generation of urban organic waste, factors that collectively intensify climate stress and environmental instability. Insects are recognised for their remarkable capacity to transform substrates into [...] Read more.

The global population continues to rise, placing increasing pressure on the agri-food sector and leading to the accelerated generation of urban organic waste, factors that collectively intensify climate stress and environmental instability. Insects are recognised for their remarkable capacity to transform substrates into valuable products, with the black soldier fly larvae (BSFL) emerging as one of the most efficient and widely utilised species for this purpose. Beyond recycling organic matter, BSFL can also mitigate microbial contamination, effectively reducing bacterial and fungal loads in waste substrates. Understanding and manipulating the genome could provide tools to improve BSFL bioconversion process and contribute to sustainability. In this review, we provide an overview of recent advances in black soldier fly genomics and genome-editing technologies. Although research in this subject remains limited, recent studies have clarified its origin, characterised its genome, and established the foundation for targeted genetic improvements to enhance by-product conversion, nutrient recovery, and environmental sustainability. Full article

(This article belongs to the Special Issue Genome Editing and Synthetic Biology in Insects)

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15 pages, 2970 KB

Open AccessArticle

Growth Inhibition, Mortality Induction, Adverse Impacts of Development, and Underlying Molecular Mechanisms of Thymol Against Spodoptera frugiperda

by Huiyin Hu, Huanqian Yao, Shuyin He, Xinyi Xie, Cuiting Liu, Veeran Sethuraman, Jingjing Zhang and Benshui Shu

Insects 2026, 17(1), 69; https://doi.org/10.3390/insects17010069 - 6 Jan 2026

Abstract

The global migratory pest, Spodoptera frugiperda, has garnered widespread attention due to the serious damage it inflicts on agricultural productivity, particularly in maize. Thymol is a phytochemical that exhibits functional diversification in plant defense, encompassing antibacterial activities and insect pest management. However, [...] Read more.

The global migratory pest, Spodoptera frugiperda, has garnered widespread attention due to the serious damage it inflicts on agricultural productivity, particularly in maize. Thymol is a phytochemical that exhibits functional diversification in plant defense, encompassing antibacterial activities and insect pest management. However, the impact of thymol on S. frugiperda is still undetermined. This study examined the growth inhibition and mortality induction in S. frugiperda larvae after thymol exposure. The detrimental effects of 2.0 and 4.0 mg/g thymol treatments on the growth and development of S. frugiperda were also examined. RNA-Seq was used to investigate the probable toxicological mechanism of thymol on S. frugiperda, resulting in the identification of 1754 and 1022 DEGs impacted by 2.0 and 4.0 mg/g thymol treatments, respectively. The DEGs associated with chitin metabolism and cuticle synthesis, hormone biosynthesis, and protein and fat digestion were subjected to additional analysis. Our findings demonstrate the efficacy of thymol in controlling S. frugiperda and lay the groundwork for understanding the molecular toxicological mechanisms of thymol on larvae. Full article

(This article belongs to the Special Issue Insects Ecology and Biological Control Applications)

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19 pages, 2586 KB

Open AccessArticle

Preliminary Evaluation of the Toxic Effects of Essential Oils as Natural Pesticides Against Maize Weevil (Sitophilus zeamais) and Its Fungal Pathogens

by Ompelege Jacqueline Phokwe, Kabelo Magoro, Mametsi Rahab Maseme and Madira Coutlyne Manganyi

Insects 2026, 17(1), 68; https://doi.org/10.3390/insects17010068 - 6 Jan 2026

Abstract

To control maize weevils (Sitophilus zeamais), a major pest of stored grains, this study explores the use of essential oils from Eucalyptus globulus and Lantana camara as natural biopesticides. Given the risks of synthetic pesticides, these oils offer a sustainable alternative. [...] Read more.

To control maize weevils (Sitophilus zeamais), a major pest of stored grains, this study explores the use of essential oils from Eucalyptus globulus and Lantana camara as natural biopesticides. Given the risks of synthetic pesticides, these oils offer a sustainable alternative. The research first identified ten fungal pathogens associated with the weevils, including the dominant species, Fusarium solani. Preliminary results showed that both oils were then tested for their ability to kill the fungi and the weevils. Eucalyptus globulus oil proved to be a superior antifungal agent, inhibiting fungal growth by up to 93%, significantly outperforming Lantana camara oil. Both oils demonstrated potent insecticidal properties, achieving 100% weevil mortality at a 10% concentration within 24 hrs. However, Eucalyptus oil was more effective, maintaining 100% mortality even at a lower 5% concentration, unlike Lantana oil. Chemical analysis showed that Eucalyptus oil’s high effectiveness may be associated with its main component, eucalyptol (52.8%). Lantana oil had a more varied composition, with caryophyllene (31%) as its primary constituent. The findings suggest that Eucalyptus globulus essential oil is a promising, two-in-one biopesticide capable of controlling both maize weevils and their associated fungal pathogens. Full article

(This article belongs to the Special Issue The Efficacy of Insecticides and Botanicals Against Pests—2nd Edition)

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18 pages, 2887 KB

Open AccessArticle

Effects of Microwave on Mortality and Detection Efficiency of Three Stored Grain Insect Adults in Stored Paddy, and on Grain Quality

by Shiyuan Miao, Yiting Zhou, Suisui Wang, Zhipeng Yang, Adrien Guverinoma, Yaru Zhao and Yujie Lu

Insects 2026, 17(1), 67; https://doi.org/10.3390/insects17010067 - 6 Jan 2026

Abstract

Microwave heating has been widely used for disinfestation in the food industry due to its selective heating. However, research on the effects of microwave heating on stored product insects is still relatively limited, which has restricted its broader application in grain pest control [...] Read more.

Microwave heating has been widely used for disinfestation in the food industry due to its selective heating. However, research on the effects of microwave heating on stored product insects is still relatively limited, which has restricted its broader application in grain pest control storage. Therefore, this study evaluated the lethal effects of different microwave powers and exposure times on three major pests in paddy and investigated the impact of microwave treatment on improving adult detection efficiency, intending to develop a rapid and efficient detection method for stored grain insects. The results showed that the mortality of Sitophilus oryzae, Tribolium castaneum, and Oryzaephilus surinamensis increased with the increase in microwave power and exposure time. Specifically, 100% mortality was achieved for both S. oryzae and T. castaneum at 700 W for 60 s exposure. However, higher power levels and longer exposure durations exacerbated the non-uniformity of grain temperature distribution and adversely affected the germination rate. In addition, microwave treatment at 350 W, 490 W, and 700 W significantly reduced fungal load in paddy. The moisture content and water activity of rice decreased with the increase in microwave power and exposure time, while the percentage of grain breakage remained largely unaffected. These findings indicated that microwave treatment can effectively control insects and fungi without significantly altering the main physical properties of paddy. Notably, microwave treatment with short exposure durations (20–30 s) at all three power levels is conducive to increasing the recovery percentage of S. oryzae adults, while microwave treatment at low power (350 W) with exposure durations of 25–40 s helps improve that of T. castaneum. Accordingly, microwave heating is not only a promising strategy for protecting stored grains but also has potential for development as a rapid detection method for specific insect pests. Full article

(This article belongs to the Special Issue Integrated Pest Management in Stored Products)

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14 pages, 1511 KB

Open AccessArticle

CarE1 and GST1 Are Involved in Beta-Cypermethrin Resistance in Field Populations of the Mirid Bug, Apolygus lucorum

by Haojie Wang, Weicheng Song, Qiyuan Wu, Liming Xu, Lin Niu and Qingbo Tang

Insects 2026, 17(1), 66; https://doi.org/10.3390/insects17010066 - 6 Jan 2026

Abstract

The widespread cultivation of transgenic Bt cotton has elevated Apolygus lucorum (Meyer-Dür) to a major pest in cotton agroecosystems. Its rapidly developing resistance to insecticides poses a serious challenge to sustainable agriculture. In this study, we assessed the susceptibility of a field-collected population [...] Read more.

The widespread cultivation of transgenic Bt cotton has elevated Apolygus lucorum (Meyer-Dür) to a major pest in cotton agroecosystems. Its rapidly developing resistance to insecticides poses a serious challenge to sustainable agriculture. In this study, we assessed the susceptibility of a field-collected population from Anyang, Henan Province, in relation to a laboratory-susceptible strain, to elucidate the present status and molecular basis of resistance to beta-cypermethrin. First, the toxicity of beta-cypermethrin to A. lucorum was assessed through a diet-incorporation method. Subsequently, the enzymatic activities of carboxylesterase (CarE) and glutathione S-transferase (GST) were measured, and the expression levels of CarE1 and GST1 were quantified by quantitative real-time PCR (qRT-PCR). Finally, the function of candidate genes was confirmed using RNA interference (RNAi) technology. The bioassays results indicated that the median lethal concentration (LC₅₀) for the laboratory and Anyang field strain were 343.34 mg/L and 700.45 mg/L, respectively. Following 48 h of exposure to the LC₃₀ of the susceptible strain, the mortality rate of the field population (20.00%) was significantly lower than that of the laboratory population (33.33%), suggesting an increase in resistance. The field population of A. lucorum exhibited significantly higher activities of CarE (1.61-fold) and GST (1.71-fold) compared to the laboratory strain, accompanied by 3.63- and 4.23-fold overexpression of the corresponding genes CarE1 and GST1. Spatiotemporal expression profiling revealed that CarE1 expression was highest in 4th–5th instar nymphs and adults, with predominant localization in the midgut, while GST1 expression peaked in 4th–5th instar nymphs and was abundant in the midgut and fat body. RNAi-mediated knockdown of CarE1 and GST1 significantly enhanced susceptibility to beta-cypermethrin in field populations, resulting in elevated mortality 48 h post-treatment compared to controls. In conclusion, the field population of A. lucorum has developed considerable resistance to beta-cypermethrin, strongly correlated with overexpression of CarE1 and GST1. These results deepen our understanding of metabolic resistance mechanisms and offer valuable insights for developing targeted pest control strategies. Full article

(This article belongs to the Special Issue Insecticide Resistance and Toxicology: Challenges in Pest Management and Basic Research—2nd Edition)

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19 pages, 2427 KB

Open AccessArticle

Terpenoid Mixtures as Repellents Against the American Cockroach: Their Synergy and Low Toxicity Against Non-Target Species

by Hataichanok Passara, Tanapoom Moungthipmalai, Chamroon Laosinwattana, Sirawut Sittichok, Kouhei Murata and Mayura Soonwera

Insects 2026, 17(1), 65; https://doi.org/10.3390/insects17010065 - 5 Jan 2026

Abstract

The repellent activities (Periplaneta americana) of lone and binary mixtures of terpenoids—geranial, trans-anethole, and trans-cinnamaldehyde—against adult American cockroaches were evaluated in this study. The respective efficacies of these mixtures were compared with that of 12% (w/w [...] Read more.

The repellent activities (Periplaneta americana) of lone and binary mixtures of terpenoids—geranial, trans-anethole, and trans-cinnamaldehyde—against adult American cockroaches were evaluated in this study. The respective efficacies of these mixtures were compared with that of 12% (w/w) DEET. Safety bioassays for all formulations on non-target species, namely, earthworms (Eudrilus eugeniae) and guppy fish (Poecilia reticulata), were conducted to identify natural compounds with repellent efficacy equal to or surpassing that of DEET while ensuring ecological safety for non-target organisms such as fish and earthworms. All mixtures (RC₅₀ of 0.3 to 1.6 µL/cm³) were more effective than all lone terpenoids (RC₅₀ of 6.2 to 9.1 µL/cm³) and DEET (RC₅₀ of 3.0 µL/cm³), demonstrating strong synergy, with an increased repellent value (IV) of 79 to 96%. The strongest repellency, 98.0% at 72 h and an RC₅₀ of 0.3 µL/cm³, was achieved using geranial + trans-cinnamaldehyde (1:1). This mixture was 5.9 to 10 times more effective as a repellent than DEET. The toxicity of every lone terpenoid and terpenoid mixture to non-target species was low; hence, these mixtures can be considered safe, whereas DEET was highly toxic to non-target species (100% mortality). The terpenoid mixture geranial + trans-cinnamaldehyde showed strong repellency against P. americana. Full article

(This article belongs to the Special Issue Urban Entomology and One Health)

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12 pages, 2220 KB

Open AccessArticle

Isolation and Identification of the Sex Pheromone of Evergestis extimalis Scopoli (Lepidoptera: Pyralidae)

by Mingang Qin, Youhua Ma, Youpeng Lai, Siyu Liu and Gui Zhang

Insects 2026, 17(1), 64; https://doi.org/10.3390/insects17010064 - 5 Jan 2026

Abstract

In Qinghai Province, Evergestis extimalis is an important pest of spring rape and is primarily controlled using chemical pesticides. Sex pheromones offer an alternative method for pest management in relatively non-polluted environments. In this study, the sex of E. extimalis pupae was identified, [...] Read more.

In Qinghai Province, Evergestis extimalis is an important pest of spring rape and is primarily controlled using chemical pesticides. Sex pheromones offer an alternative method for pest management in relatively non-polluted environments. In this study, the sex of E. extimalis pupae was identified, followed by isolation and structural characterization of female pheromone components using GC-EAD and GC-MS. A field attraction assay was then performed. The results showed that female pupae possess a longitudinal crack on the upper central ventral surface of the eighth abdominal segment, which connects the seventh and ninth abdominal segments. The two sides of this crack are open and flat, without protruding semicircles. Male pupae lack this longitudinal crack on the eighth abdominal segment but display one on the central ninth ventral segment, accompanied by semicircular tubercles on each side. The primary component extracted from female sex glands was identified as E11-14Ac. In field trials, E11-14 displayed a stronger attractive effect on E. extimalis males than the other tested attractants. In conclusion, E11-14Ac was preliminarily identified as the main component of the sex pheromone of E. extimalis, providing a foundation for its control using sex pheromones. Full article

(This article belongs to the Section Insect Pest and Vector Management)

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