Insects

16 pages, 5067 KB

Open AccessArticle

Response of Leafhopper Community Structure and Diversity to Fragmented Habitat in a Rocky Karst Desertification Area, Guizhou, China

by Wenming Xu, Jinqiu Wang, Yuanqi Zhao and Yuehua Song

Insects 2026, 17(1), 42; https://doi.org/10.3390/insects17010042 (registering DOI) - 29 Dec 2025

Abstract

Guizhou Province is located in the karst area of southern China, where rocky desertification is severe, and habitat fragmentation is prominent. Leafhoppers are widely distributed, with over 2000 recognized species found in China. However, the impact of habitat fragmentation in karst areas on [...] Read more.

Guizhou Province is located in the karst area of southern China, where rocky desertification is severe, and habitat fragmentation is prominent. Leafhoppers are widely distributed, with over 2000 recognized species found in China. However, the impact of habitat fragmentation in karst areas on the biodiversity of leafhoppers has not been comprehensively explored. Leafhopper specimens were collected in Bijie City, Guizhou Province (a light to moderate karst rocky desertification area) from 2019 to 2022. Using methods such as the generalized linear model (GLM) and redundancy analysis (RDA), this study explored the impacts of habitat fragmentation and environmental factors (plants, soil, climate) on the genus-level and genetic diversity of leafhoppers. When the degree of habitat fragmentation decreased, the genus diversity of leafhoppers increased significantly. The GLM showed that among the characteristics of fragmented habitats, patch area had the greatest impact on the generic richness of leafhoppers. RDA indicated that gene exchange among leafhoppers was more frequent between patches with irregular boundaries, and leafhoppers in patches with small areas and complex boundaries had greater genetic diversity. As phytophagous insects, leafhoppers were mainly affected by host plants and less affected by soil properties. Mitigating habitat fragmentation had a positive impact on the biodiversity of leafhoppers, which emphasizes the necessity of protecting biodiversity by reducing habitat fragmentation in the future. Full article

(This article belongs to the Section Insect Ecology, Diversity and Conservation)

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16 pages, 914 KB

Open AccessArticle

Active Assessment of Female Codling Moth, Cydia pomonella (L.), Mating Status Under Mating Disruption Technologies

by Alan Lee Knight, Michele Preti and Esteban Basoalto

Insects 2026, 17(1), 41; https://doi.org/10.3390/insects17010041 - 28 Dec 2025

Abstract

Most assessments of sex pheromone-based mating disruption (MD) for codling moth (CM), Cydia pomonella (L.), have not included measurements of female mating. The recent development of a dual-sex lure (CM4K) combining ethyl (E,Z)-2,4-decadienoate, 4,8-dimethyl-1,3,7-nonatriene, pyranoid linalool oxide, and acetic [...] Read more.

Most assessments of sex pheromone-based mating disruption (MD) for codling moth (CM), Cydia pomonella (L.), have not included measurements of female mating. The recent development of a dual-sex lure (CM4K) combining ethyl (E,Z)-2,4-decadienoate, 4,8-dimethyl-1,3,7-nonatriene, pyranoid linalool oxide, and acetic acid has significantly increased the catch of female CM and made it easier to directly assess various MD programs. Samples of wild female CM populations using this lure were collected from 142 orchards, either untreated or treated with one of seven different dispenser systems for CM MD, from 2021 to 2022. The proportion of unmated females ranged from <0.20 to >0.80 with a median of 0.43 in both years. No differences in the mean proportion of unmated females were found between apple and pear. Moth immigration and supplemental insecticide sprays were hypothesized to be key factors affecting the variability within each MD tactic. Mating levels were significantly higher later in the season. More females were unmated in conventional compared with organic orchards. Means for females not mating among the CM MD programs varied over a 0.20 range, except for one. The exception occurred when two MD tactics (aerosol units plus hand-applied dispensers) were accidentally used together, and the proportion of unmated females was significantly higher. Full article

(This article belongs to the Special Issue Tortricid Moths (Lepidoptera: Tortricidae): Biology, Ecology and Integrated Pest Management)

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21 pages, 3042 KB

Open AccessArticle

Temperature Changes Affect the Vulnerability of Cotton Bollworms, Helicoverpa armigera (Hübner)

by Jian Huang, Pengfei Wu, Wenyuan Xing and Xiaojun Wang

Insects 2026, 17(1), 40; https://doi.org/10.3390/insects17010040 - 28 Dec 2025

Abstract

The cotton bollworm, Helicoverpa armigera (Hübner), a cosmopolitan agricultural pest, inflicts severe impacts on global agriculture. As a poikilotherm, it was highly susceptible to climate change, yet critical gaps persist in understanding how its sensitivity interacts with climatic shifts—knowledge essential for integrated pest [...] Read more.

The cotton bollworm, Helicoverpa armigera (Hübner), a cosmopolitan agricultural pest, inflicts severe impacts on global agriculture. As a poikilotherm, it was highly susceptible to climate change, yet critical gaps persist in understanding how its sensitivity interacts with climatic shifts—knowledge essential for integrated pest management (IPM). We, therefore, analyzed H. armigera’s susceptibility to temperature variations using long-term pest population and meteorological data from Maigaiti and Bachu Counties (southern Xinjiang) and Shawan County (northern Xinjiang). The results showed H. armigera populations increased overall, with reduced interannual fluctuation magnitude. The main meteorological factors influencing the interannual population changes of H. armigera in Maigaiti, Bachu, and Shawan were T_max difference in winter (98.0%), T_min difference in May (80.7%), and T_min difference in July (99.4%), respectively. Higher winter temperature (particularly February) reduced the spring population sizes across all three regions, with only the population in Bachu showing a significant correlation. For annual populations, warmer winter caused a significant decline in Bachu, a marked increase in Maigaiti, and a non-significant rise in Shawan. Summer temperature below 33 °C boosted populations in all regions; above 33 °C, the Maigaiti population declined non-significantly, while the Bachu population dropped significantly. Climate warming advanced the pest’s first appearance, delayed its disappearance, and extended its active period, increasing population size—a trend projected to intensify in the future. Maigaiti and Shawan populations were governed by T_max in winter and T_min in July, respectively, whereas the Bachu population was constrained by temperature differences during multiple key growth and development periods throughout the year. These divergent regulatory patterns and climatic responses reflect varying vulnerability levels, providing a theoretical basis for targeted H. armigera control. Full article

(This article belongs to the Special Issue Cotton Pest Management)

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21 pages, 8711 KB

Open AccessArticle

Phylogenetic and Morphological Analysis of Wing Base Articulation in Vespidae (Hymenoptera): A Cladistic Approach

by Hasin Ullah, Xiaojuan Huang, Yao Zhang, Jia Li, Danyang Zhu, Chenlu Yang, Yuan Hua, Lian-Xi Xing and Jiangli Tan

Insects 2026, 17(1), 39; https://doi.org/10.3390/insects17010039 - 27 Dec 2025

Abstract

Insect wing base sclerites are crucial to wing function and evolution, yet their diversity beyond order-level comparisons remains poorly understood. We examine variation in wing base sclerites across Vespidae, focusing on the axillary sclerites (1Ax, 2Ax, and 3Ax), the shoulder sclerite, and associated [...] Read more.

Insect wing base sclerites are crucial to wing function and evolution, yet their diversity beyond order-level comparisons remains poorly understood. We examine variation in wing base sclerites across Vespidae, focusing on the axillary sclerites (1Ax, 2Ax, and 3Ax), the shoulder sclerite, and associated structures. The first axillary sclerite shows distinct regional differentiation and bears a well-sclerotized knob that influences wing articulation. Additionally, 2Ax in Vespidae is a single, triangular structure with three attachment points, distinct from the two-part composition in some other wasps, which facilitates high-frequency wing vibrations. Our findings also highlight variable fusion patterns in 3Ax and its interaction with 2Ax, contributing to wing flexibility. The basiradial bridge, connecting the subcostal and radial veins, reinforces wing stability and articulation. Phylogenetic analysis based on wing-base morphology does not support the monophyly of Vespidae and differs from molecular hypotheses, but it refines previous morphological interpretations. The well-supported subfamily relationships confirm Vespinae as a monophyletic group and reveal a close association among Polistinae, Stenogastrinae, and Eumeninae, as represented by Polistes, Eustenogaster, and Oreumenes, respectively, suggesting evolutionary transitions in social behavior within the family Vespidae. The absence of a fourth axillary sclerite challenges earlier hypotheses, providing new insights into Hymenopteran wing base evolution. Two articulation models are proposed for forewings and hindwings, supported by three-dimensional reconstructions of axillary sclerites, indirect and direct flight muscles, and their attachment sites. These results refine interpretations of wasp wing mechanics, evolution, and morphological diversification across taxa. Full article

(This article belongs to the Special Issue Selected Papers from the Second International Electronic Conference on Entomology)

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9 pages, 1170 KB

Open AccessArticle

Foraging Patterns of Two Sympatric Wasp Species: The Worldwide Invasive Polistes dominula and the Native Hypodynerus labiatus

by Sabrina Moreyra and Mariana Lozada

Insects 2026, 17(1), 38; https://doi.org/10.3390/insects17010038 - 27 Dec 2025

Abstract

Invasive insects pose significant ecological challenges due to their interactions with other species, which can have a considerable impact on pre-existent ecosystems. In the present study, we analysed the foraging behaviour of the invasive Polistes dominula, which was first detected in NW [...] Read more.

Invasive insects pose significant ecological challenges due to their interactions with other species, which can have a considerable impact on pre-existent ecosystems. In the present study, we analysed the foraging behaviour of the invasive Polistes dominula, which was first detected in NW Patagonia in 2003, and the native wasp Hypodynerus labiatus. We evaluated their foraging behaviour in two types of environments: closed habitats with dense vegetation and open habitats without surrounding bushes and trees. Additionally, we recorded the wasps’ feeding choices at three different heights within each context. Our results showed that these sympatric wasps prefer to forage in different environments and in distinct microsite strata within each environment. Polistes dominula collected food from the ground level in both open and closed habitats, while H. labiatus was more frequently observed in closed areas, gathering resources from higher strata. The observed differences suggest that the collecting sites showed minimal overlap, which may facilitate their coexistence. These findings shed new light on the behavioural processes and interspecific interactions between a highly invasive wasp and a poorly studied native species that inhabit urban and semi urban environments in Patagonia. Full article

(This article belongs to the Special Issue Systematic and Biological Studies on Hymenoptera: Vespidae)

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12 pages, 4098 KB

Open AccessArticle

Integrative Taxonomy Clarifies the Taxonomic Status of the Morphologically Intermediate Form Between Tropidothorax cruciger and T. sinensis (Hemiptera: Lygaeidae)

by Chenguang Zheng, Xiuxiu Zhu, Yaning Zhang, Ying Wang and Wenjun Bu

Insects 2026, 17(1), 37; https://doi.org/10.3390/insects17010037 - 26 Dec 2025

Abstract

(1) Background: The identification of Tropidothorax cruciger and T. sinensis is often complicated by the presence of the “intermediate form”. Due to the lack of molecular data, the taxonomic status of the “intermediate form” and the species boundaries between T. cruciger and T. [...] Read more.

(1) Background: The identification of Tropidothorax cruciger and T. sinensis is often complicated by the presence of the “intermediate form”. Due to the lack of molecular data, the taxonomic status of the “intermediate form” and the species boundaries between T. cruciger and T. sinensis remain uncertain; (2) Methods: In this study, we integrated morphological, molecular, and ecological data to delimit species boundaries of these two species using multiple species delimitation approaches; (3) Results: Most species delimitation analyses based on the cytochrome c oxidase subunit I (COI) fragment suggested that T. cruciger and the “intermediate form” comprised a single species, with T. sinensis representing a separate species. This delimitation result was also supported by the analyses of BFD* and genetic clustering based on genome-wide SNPs. Under this species delimitation scenario, a clear-cut barcode gap was discovered between the interspecific and intraspecific genetic distances. In addition, environmental-related analyses showed highly similar ecological requirements of T. cruciger and the “intermediate form”, supporting their recognition as a single species; (4) Conclusions: This study clarifies the taxonomic status of the “intermediate form” and the species boundaries between T. cruciger and T. sinensis, which is essential for further studies of ecology and evolution of these species. Full article

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

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22 pages, 3184 KB

Open AccessArticle

Evaluating the Influence of Trap Type and Crop Phenological Stage on Insect Population Diversity in Mediterranean Open-Field Tomatoes

by Nada Abdennour, Mehdia Fraj, Ramzi Mansour, Amal Ghazouani, Ahmed Mahmoud Ismail, Hossam S. El-Beltagi, Mohamed M. El-Mogy, Sherif Mohamed El-Ganainy, Wael Elmenofy, Mohamed J. Hajjar, Shimat V. Joseph and Sabrine Attia

Insects 2026, 17(1), 36; https://doi.org/10.3390/insects17010036 - 26 Dec 2025

Abstract

The relationship between insect diversity and crop production has been of continuous scientific interest. Understanding insect community dynamics using various sampling and monitoring methods at different crop phenology stages is crucial for enhancing pest management and ecosystem service functioning. The present study assessed [...] Read more.

The relationship between insect diversity and crop production has been of continuous scientific interest. Understanding insect community dynamics using various sampling and monitoring methods at different crop phenology stages is crucial for enhancing pest management and ecosystem service functioning. The present study assessed the influence of four trap types (Blue, Yellow, White, and Malaise) applied at four tomato developmental stages (start of planting, flowering, flowering fruit development and harvest) on insect diversity in northeastern Tunisian open-field conditions. A total of 1771 insect individuals belonging to seven orders and 31 families were trapped, with the order Hymenoptera being the most common in the sampled plots, which was represented by 25 families. Trap type exerted a strong effect on both abundance and alpha diversity parameters. Yellow pan traps showed the highest diversity, with family richness (S) ranging from 1 to 16, Shannon diversity (H) reaching 2.54, Simpson (Is) diversity ranging from 0.72 to 0.90 and Pielou’s evenness (J) ranging from 0.83 to 0.98. Blue and white traps displayed intermediate diversity (Blue: S = 6 and H = 1.7; White: S = 7 and H = 1.6), while Malaise traps captured the least diverse assemblages (S = 4, H = 1.2 and Is = 0.65). These differences were highly significant (p < 0.05). Phenological stage significantly structured Hymenoptera diversity. Richness peaked at the start of planting (S = 1–16 and H up to 2.54) and declined sharply at harvest (S = 1–6). Pollinator families (Apidae, Halictidae, Megachilidae) were the most abundant during flowering, whereas parasitoid families (Braconidae, Eulophidae) dominated during the fruit development stage. Beta diversity analyses (NMDS, stress = 0.25) and PERMANOVA showed that trap type and phenological stage jointly explained 15.5% of the variation in community composition (R² = 0.155, p = 0.014). Although a strong taxonomic overlap among traps was observed, Indicator Value analysis revealed significant trap-specific associations, including the family Andrenidae with Blue traps and the family Scoliidae with White and Yellow traps. Overall, the results of the present study demonstrate that both trap type and crop phenology significantly influence insect population diversity. A multi-trap sampling strategy combining colored pan traps and Malaise traps could be recommended to accurately characterize insect communities and associated ecosystem services in Mediterranean open-field tomato systems. Full article

(This article belongs to the Special Issue Advances on Conservation of Biodiversity, Monitoring Programs and Trend Assessment)

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21 pages, 4529 KB

Open AccessReview

Exploring the Role of Pheromones and CRISPR/Cas9 in the Behavioral and Olfactory Mechanisms of Spodoptera frugiperda

by Yu Wang, Chen Zhang, Mei-Jun Li, Asim Iqbal, Kanwer Shahzad Ahmed, Atif Idrees, Habiba, Bai-Ming Yang and Long Jiang

Insects 2026, 17(1), 35; https://doi.org/10.3390/insects17010035 - 25 Dec 2025

Abstract

Globally, Spodoptera frugiperda is a major threat to many important crops, including maize, rice, and cotton, causing significant economic damage. To control this invasive pest, environmentally friendly pest control techniques, including pheromone detection and identification of potential molecular targets to disrupt S. frugiperda [...] Read more.

Globally, Spodoptera frugiperda is a major threat to many important crops, including maize, rice, and cotton, causing significant economic damage. To control this invasive pest, environmentally friendly pest control techniques, including pheromone detection and identification of potential molecular targets to disrupt S. frugiperda mating communication, are needed. Female moths biosynthesize pheromones and emit them from the pheromone gland, which significantly depends on the intrinsic factors of the moth. Male S. frugiperda have a sophisticated olfactory circuit on their antennae that recognizes pheromone blends via olfactory receptor neurons (ORNs). With its potential to significantly modify the insect genome, CRISPR/Cas9 offers a revolutionary strategy to control this insect pest. The impairing physiological behaviors and disrupting the S. frugiperda volatile-sensing mechanism are the main potential applications of CRISPR/Ca9 explored in this review. Furthermore, the release of mutant S. frugiperda for their long-term persistence must be integral to the adoption of this technology. Looking forward, CRISPR/Cas9-based gene drive systems have the potential to synergistically target pheromone signaling pathways in S. frugiperda by disrupting pheromone receptors and key biosynthesis genes, thereby effectively blocking intraspecific communication and reproductive success. In conclusion, CRISPR/Cas9 provides an environmentally friendly and revolutionary platform for precise, targeted pest management in S. frugiperda. Full article

(This article belongs to the Special Issue Spodoptera frugiperda: Current Situation and Future Prospects)

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15 pages, 278 KB

Open AccessArticle

Phytochemical Profiling and Larvicidal Activity of Ethanolic Extracts from Persea americana Mill. (Var. Lorena) Against Aedes aegypti

by Clara Barragán-Avilez, Paula Pareja-Loaiza, Katherine Girón Domínguez, Beatriz López-Monroy, Adriana E. Flores, Martha Sánchez-Bolívar, Jaime Luna-Carrascal, Leonardo C. Pacheco-Londoño, Nataly J. Galán-Freyle, Elkin Navarro Quiroz, Karina Castellanos-Romero, Ronald Maestre-Serrano, Roger Valle-Molinares and Fabián Espitia-Almeida

Insects 2026, 17(1), 34; https://doi.org/10.3390/insects17010034 - 25 Dec 2025

Abstract

Dengue is a mosquito-borne viral disease transmitted by Aedes aegypti, the main vector in the Americas. The lack of effective antiviral treatments, limited vaccine coverage, and the increasing resistance of mosquitoes to conventional insecticides emphasize the need for alternative vector control strategies. [...] Read more.

Dengue is a mosquito-borne viral disease transmitted by Aedes aegypti, the main vector in the Americas. The lack of effective antiviral treatments, limited vaccine coverage, and the increasing resistance of mosquitoes to conventional insecticides emphasize the need for alternative vector control strategies. Plant-derived larvicides represent a promising and eco-friendly approach. This study characterized the phytochemical profile of Persea americana Mill. (var. Lorena) and evaluated its larvicidal activity against Ae. aegypti (Rockefeller strain). The phytochemical profile was assessed through qualitative screening, UV-Vis spectrophotometry, and UHPLC analysis. Larvicidal activity was evaluated against third-instar larvae of Ae. aegypti (Rockefeller strain) and the median lethal concentration (LC₅₀) values were determined. Preliminary screening of ethanolic extracts revealed the presence of various secondary metabolites of pharmacological relevance, including alkaloids, coumarins, tannins, flavonoids, saponins, triterpenes/sterols, and quinones. UV-Vis spectra displayed distinct absorption patterns, with a prominent peak near 260 nm, consistent with the presence of aromatic compounds. UHPLC profiling revealed high chemical diversity across different plant parts, with 70, 98, 71, and 52 peaks (above 1 × 10⁵ intensity) detected in seed, flower, pulp, and leaf extracts, respectively. Larvicidal bioassays showed significant activity, particularly in the seed extract, with LC₅₀ values (µg/mL) of 3.8 (3.3–4.1) for seeds, 22.4 (21.8–23.9) for flowers, 23.0 (21.5–24.6) for pulp, and 29.7 (28.1–31.2) for leaves. This study highlights the larvicidal potential of ethanolic extracts from P. americana (var. Lorena), with the seed extract exhibiting the highest chemical diversity and bioactivity against Ae. aegypti larvae. The detection of key secondary metabolites, including flavonoids, alkaloids, and saponins, supports the development of an effective, plant-based larvicide for sustainable vector control strategies. Full article

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

15 pages, 32122 KB

Open AccessArticle

Functional Analysis of the Scarlet Gene in the Cricket Gryllus bimaculatus

by Li-Fen Zeng, Yun Bai, Long Chen, Xin-Kun Yang, Jin-Li Xu, Zhu-Qing He and Kai Li

Insects 2026, 17(1), 33; https://doi.org/10.3390/insects17010033 - 25 Dec 2025

Abstract

The scarlet gene encodes an ATP-binding cassette transporter involved in eye pigmentation across various insect species. In this study, we functionally characterized the scarlet homolog (Gbst) in the cricket Gryllus bimaculatus, a hemimetabolous model organism. Clustered regularly interspaced short palindromic [...] Read more.

The scarlet gene encodes an ATP-binding cassette transporter involved in eye pigmentation across various insect species. In this study, we functionally characterized the scarlet homolog (Gbst) in the cricket Gryllus bimaculatus, a hemimetabolous model organism. Clustered regularly interspaced short palindromic repeats/CRISPR-associated nuclease 9-mediated knockout of Gbst generated a stable yellow-eyed mutant line (Gbst^−/−) with changed pigmentation evident from embryogenesis through adulthood. Quantitative real-time PCR analysis showed that scarlet expression was extremely low in Gbst^−/−, and the transcript levels of white and brown were also reduced. Histological sections of the compound eyes showed that both WT and Gbst^−/− mutant possessed complete and well-defined ommatidial structures, indicating that the scarlet gene does not affect compound eye structure. In addition, reproduction tests showed that knockout of the Gbst gene did not affect egg production or embryonic viability. These findings demonstrate that Gbst is a key factor involved in eye pigmentation in G. bimaculatus, and has potential for application as a visual transgenic marker gene. Full article

(This article belongs to the Section Insect Molecular Biology and Genomics)

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15 pages, 2684 KB

Open AccessArticle

Thermal Ecology and Homeostasis in Colonies of the Neotropical Arboricolous Ant Azteca chartifex spiriti (Formicidae: Dolichoderinae)

by Josieia Teixeira dos Santos, Elmo Borges de Azevedo Koch, Julya Lopes dos Santos, Laís da Silva Bomfim, Jacques Hubert Charles Delabie and Cléa dos Santos Ferreira Mariano

Insects 2026, 17(1), 32; https://doi.org/10.3390/insects17010032 - 25 Dec 2025

Abstract

Arboreal ants occupy a thermally dynamic environment, yet the mechanisms integrating nest architecture and worker behavior to maintain colony homeostasis remain understudied. We investigated the interplay among circadian rhythm, nest homeostasis, and worker morphology in Azteca chartifex spiriti, a Neotropical arboreal species [...] Read more.

Arboreal ants occupy a thermally dynamic environment, yet the mechanisms integrating nest architecture and worker behavior to maintain colony homeostasis remain understudied. We investigated the interplay among circadian rhythm, nest homeostasis, and worker morphology in Azteca chartifex spiriti, a Neotropical arboreal species that builds large polydomous nests suspended in trees. In ten colonies, we measured internal moisture and temperature gradients in the main nest, which houses most individuals, including the reproductive female, immatures, and numerous workers. In six colonies, we assessed the polymorphism of foraging workers over a 24 h cycle in relation to external temperature variation. The results show integrated thermoregulatory mechanisms that combine passive strategies, derived from nest architecture and moisture gradients from the suspension base to the lower extremity, with active strategies linked to foraging patterns and worker polymorphism. Internal temperature (27.8 ± 2.41 °C) remained buffered relative to external fluctuations, and moisture was significantly higher at the nest’s lower extremity (p < 0.001). Worker size displayed a bimodal distribution during the day that shifted to a unimodal pattern at night, indicating behavioral adjustments to thermal and operational demands. These findings demonstrate that the interaction between physical structure and worker behavior maintains colony homeostasis, providing essential insights into how dominant canopy ants may cope with future climate change scenarios. Full article

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

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19 pages, 2799 KB

Open AccessArticle

Infestation, Community Structure, and Seasonal Dynamics of Chiggers on Small Mammals at a Focus of Scrub Typhus in Northern Yunnan, Southwest China

by Yan Lv, Peng-Wu Yin, Xian-Guo Guo, Rong Fan, Cheng-Fu Zhao, Zhi-Wei Zhang, Ya-Fei Zhao and Lei Zhang

Insects 2026, 17(1), 31; https://doi.org/10.3390/insects17010031 - 24 Dec 2025

Abstract

Chiggers are common ectoparasites and the exclusive vector of scrub typhus. From November 2020 to October 2021, a 12-month investigation was conducted at Waxi Village of Binchuan County, Yunnan Province of southwest China, a focus of scrub typhus. A total of 217,671 chiggers [...] Read more.

Chiggers are common ectoparasites and the exclusive vector of scrub typhus. From November 2020 to October 2021, a 12-month investigation was conducted at Waxi Village of Binchuan County, Yunnan Province of southwest China, a focus of scrub typhus. A total of 217,671 chiggers collected from 1329 small mammal hosts (belonging to 18 species) at the survey site were taxonomically identified as 115 species and 13 genera in the family Trombiculidae with high species diversity. Among the 115 chigger species identified, there were nine vector species. The prevalence (P_M = 69.38%), mean abundance (MA = 163.79 mites/per examined host), and mean intensity (MI = 236.09 mites/per infested host) were high. Three rodent species, Rattus andamanensis, Apodemus chevrieri, and Mus caroli, were the dominant hosts. Three vector chiggers, L. deliense, L. scutellare, and L. imphalum, were the dominant chiggers, with a constituent ratio (C_r) of 60.72%. The indexes of chigger infestation and community showed varying degrees of monthly and seasonal fluctuations. From August (summer) to September and October (autumn), the Margalef richness index (R), Shannon–Wiener diversity index (H), and Pielou evenness (E) of chiggers were at low levels, but the Simpson dominance index (D) was at a high level. The C_r and infestation indexes (MA, MI) of chiggers were high from August to October in summer and autumn, with abundant vector chiggers (such as L. deliense and L. imphalum) appearing in these seasons. The species richness of chigger community was highest in winter, but lowest in summer. The similarity of the chigger community was very high between August (summer) and September to October (autumn). The evenness of the chigger community was highest in spring and lowest in summer. In conclusion, small mammals are susceptible to chigger infestation with coexistence of multiple vector chigger species. Most chigger species have a wide range of hosts with low host specificity. The abundant vector chiggers (especially L. deliense and L. imphalum) in summer and autumn suggests that the surveillance campaign of scrub typhus and vector chiggers should mainly focus on these two seasons at the survey site. Full article

(This article belongs to the Section Medical and Livestock Entomology)

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76 pages, 6452 KB

Open AccessArticle

A New Comprehensive Generic Framework for Tettigometra Latreille, 1804 s.l.: A Taxonomic and Nomenclatural Revision of the Tribe Tettigometrini (Hemiptera: Fulgoromorpha)

by Fariba Mozaffarian and Thierry Bourgoin

Insects 2026, 17(1), 30; https://doi.org/10.3390/insects17010030 - 24 Dec 2025

Abstract

The taxonomy of Tettigometra Latreille, 1804 s.l. (Hemiptera, Tettigometridae, Tettigometrini) has long remained unstable due to weak diagnostic characters, conflicting interpretations, and frequent misidentifications. Based on extensive examination of the illustrated literature and major museum collections, a new generic framework is proposed, relying [...] Read more.

The taxonomy of Tettigometra Latreille, 1804 s.l. (Hemiptera, Tettigometridae, Tettigometrini) has long remained unstable due to weak diagnostic characters, conflicting interpretations, and frequent misidentifications. Based on extensive examination of the illustrated literature and major museum collections, a new generic framework is proposed, relying primarily on comparative analyses of male genital morphology (particularly the mediodorsal aedeagal process and paired ventral anal processes) while external morphology alone is shown to be unreliable for stable delimitation. In discussing the need for a taxonomy that is both phylogenetically grounded and operational, allowing reliable identifications, preserving compatibility with past determinations despite the lack of molecular evidence, and remaining flexible enough to accommodate future results, we recognize two informal taxonomic groups and fourteen genera. The tettigometrinan group includes Tettigometra, Brachyceps, Metroplaca, Mimarada, Mediodentometra gen. nov., and Persiametra gen. nov.; the apexometrinan group includes Apexometra gen. nov., Erratometra gen. nov., Eurychila, Hystrigonia, Micracanthometra gen. nov., Mitricephalus, Stirometra, and Macrometrina. Following a conservative and operational taxonomic approach, we refrained from describing new species or accepting unsubstantiated synonymies, preferring to retain potentially distinct forms as provisionally valid species pending molecular confirmation. Each taxon is listed with its taxonomic and nomenclatural status, diagnosis, species composition, and distribution. Problematic taxa and misapplied names are clarified, and a key to genera is provided. Full article

(This article belongs to the Special Issue Revival of a Prominent Taxonomy of Insects—2nd Edition)

16 pages, 3236 KB

Open AccessArticle

Identification and Expression Analysis of the Cytochrome P450 Genes in Phyllotreta striolata and CYP6TH1/CYP6TH2 in the Involvement of Pyridaben Tolerance

by Yongqin Zhu, Zhongting Liu, Wenyong Mai, Xinhua Pu, Haoyue Mo, Benshui Shu and Zhongzhen Wu

Insects 2026, 17(1), 29; https://doi.org/10.3390/insects17010029 - 24 Dec 2025

Abstract

The striped flea beetle, Phyllotreta striolata, is a worldwide pest that causes severe damage to cruciferous crops. Pyridaben, an inhibitor of mitochondrial complex I, has been widely used for the control of P. striolata. Identifying key genes involved in pyridaben tolerance [...] Read more.

The striped flea beetle, Phyllotreta striolata, is a worldwide pest that causes severe damage to cruciferous crops. Pyridaben, an inhibitor of mitochondrial complex I, has been widely used for the control of P. striolata. Identifying key genes involved in pyridaben tolerance is vital for establishing effective resistance management strategies. A total of 94 full-length cytochrome P450 (CYP) genes were identified in P. striolata. The identified genes were classified into four clans (mitochondrial, CYP2, CYP3, and CYP4), 23 families, and 57 subfamilies. Transcriptomic analysis across developmental stages and tissues revealed distinct expression patterns were seen in these P450 genes. Pyridaben exposure significantly upregulated the expression of CYP6TH1 and CYP6TH2. Tissue-specific expression profiling indicated that CYP6TH1 and CYP6TH2 were highly expressed in the head and fat body. RNA interference-mediated knockdown of these genes significantly increased the susceptibility of P. striolata to pyridaben. Molecular docking confirmed stable binding between pyridaben and both CYP proteins, with binding free energies of −7.73 and −7.57 kcal/mol for CYP6TH1 and CYP6TH2, respectively. This study demonstrates that CYP6TH1 and CYP6TH2 play critical roles in pyridaben tolerance in P. striolata, which highlights promising genetic targets for future resistance management strategies. Full article

(This article belongs to the Section Insect Molecular Biology and Genomics)

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18 pages, 2408 KB

Open AccessArticle

Unlocking the Potential of Bacillus Strains for a Two-Front Attack on Wireworms and Fungal Pathogens in Oat

by Aneta Buntić, Marina Dervišević Milenković, Jelena Pavlović, Uroš Buzurović, Jelena Maksimović, Marina Jovković and Magdalena Knežević

Insects 2026, 17(1), 28; https://doi.org/10.3390/insects17010028 - 24 Dec 2025

Abstract

(1) Background: Oat (Avena sativa L.) is a crop that is widely used in human nutrition, while it also plays an important role in animal husbandry as a high-quality forage crop. However, this crop is particularly susceptible to combined biotic stressors, including [...] Read more.

(1) Background: Oat (Avena sativa L.) is a crop that is widely used in human nutrition, while it also plays an important role in animal husbandry as a high-quality forage crop. However, this crop is particularly susceptible to combined biotic stressors, including insect pests (Agriotes lineatus) and fungal infections (Fusarium spp.). These stresses act synergistically: root damage caused by wireworms increases the plant’s susceptibility to fungal infection, while pathogens further limit nutrient uptake and root system development. In recent years, the reduced efficacy of chemical pesticides against both insect pests and fungal pathogens has highlighted the need for alternative strategies in oat protection, leading to an increased focus on developing bacterial bio-inoculants as sustainable and effective biocontrol agents. (2) Methods: This study aimed to identify bacterial strains capable of suppressing wireworms (Agriotes lineatus) and Fusarium spp. in oats, while simultaneously promoting plant growth. Bacterial isolates were screened for key Plant Growth Promoting (PGP) and biocontrol traits, including IAA and siderophore production, phosphate solubilization, and the presence of toxin- and antibiotic-coding genes. (3) Results: The highest insecticidal effect against wireworms was recorded for Bacillus velezensis BHC 3.1 (63.33%), while this isolate also suppressed the growth of F. proliferatum for 59%, F. oxysporum for 65%, F. poae for 71%, and F. graminearum for 15%. The most effective Bacillus strains (with insecticidal and antifungal activity) were identified and tested in two pot experiments, where their ability to enhance plant growth in the presence of insects and fungi was evaluated under semi-controlled conditions. An increase in plant biomass, grain yield, and nitrogen content was observed in oat inoculated with B. velezensis BHC 3.1 and B. thuringiensis BHC 2.4. (4) Conclusions: These results demonstrate the strong potential of both strains as multifunctional bio-inoculants for enhancing oat growth and mitigating the adverse effects of wireworm damage and Fusarium infection. Full article

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

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14 pages, 3352 KB

Open AccessArticle

An XGBoost-Based Morphometric Classification System for Automatic Subspecies Identification of Apis mellifera

by Miaoran Zhang, Yali Du, Xiaoyin Deng, Jinming He, Haibin Jiang, Yuling Liu, Jingyu Hao, Peng Chen, Kai Xu and Qingsheng Niu

Insects 2026, 17(1), 27; https://doi.org/10.3390/insects17010027 - 24 Dec 2025

Abstract

The conservation and breeding of the western honey bee (Apis mellifera) is central dependent on accurate subspecies assignment, but the most commonly used methods are labor-intensive classical morphometrics and costly molecular assays. We developed an XGBoost-based classification framework using a compact [...] Read more.

The conservation and breeding of the western honey bee (Apis mellifera) is central dependent on accurate subspecies assignment, but the most commonly used methods are labor-intensive classical morphometrics and costly molecular assays. We developed an XGBoost-based classification framework using a compact set of routinely measurable characters. A curated dataset of labeled workers was measured under harmonized protocols; features were screened according to embedded importance, and model performance was assessed using five-fold cross-validation, outperforming standard machine learning baselines. The resulting model using only the top 10 characters—primarily forewing venation angles and abdominal plate metrics—achieved high performance (accuracy = 0.98; F1 = 0.99) and an area under the receiver operating characteristic curve (AUC) of 0.99 (95% CI = 0.995–0.999). SHAP analyses confirmed the discriminatory contributions of these features, while error inspection suggested that misclassifications were concentrated in morphologically overlapping lineages. The model’s performance supports its use as a rapid triage tool alongside genetic testing, providing a scalable and interpretable tool for researchers to create and deploy custom morphometric models, demonstrated here for A. mellifera but portable to other insect taxa. Full article

(This article belongs to the Special Issue Biology and Conservation of Honey Bees)

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20 pages, 774 KB

Open AccessReview

Sublethal Effects of Neonicotinoids: How Physiological and Behavioral Disruptions in Non-Target Insects Threaten Biodiversity and Ecosystem Services

by Sarah K. Spence, Shorooq A. M. Alharbi, Afure Ejomah, Feizollah A. Maleki, Michael S. Wolfin and Mônica F. Kersch-Becker

Insects 2026, 17(1), 26; https://doi.org/10.3390/insects17010026 - 24 Dec 2025

Abstract

Neonicotinoid insecticides were initially hailed as safer alternatives to organochlorine and organophosphate pesticides due to their perceived lower toxicity to non-target organisms. However, it has been recently discovered that sublethal exposure to neonicotinoids negatively affects beneficial arthropods that are essential for a functional [...] Read more.

Neonicotinoid insecticides were initially hailed as safer alternatives to organochlorine and organophosphate pesticides due to their perceived lower toxicity to non-target organisms. However, it has been recently discovered that sublethal exposure to neonicotinoids negatively affects beneficial arthropods that are essential for a functional ecosystem. These beneficial arthropods include pollinators, biological control agents, and decomposers. This review synthesizes current research on the physiological, behavioral, and reproductive consequences of neonicotinoids on non-target arthropods and their broader ecological impact. The chemical and physical properties of neonicotinoids raise concerns about long-term ecological consequences of neonicotinoid use because these chemicals are persistent in plants and soil, which contributes to prolonged exposure risks for organisms. Sublethal doses of neonicotinoids can disrupt the ecological services provided by these organisms by impairing essential biological processes including motor function, odor detection, development, and reproduction in insects, while also altering behavior such as foraging, mating, and nesting. Furthermore, neonicotinoid exposure can alter community structure, disrupting trophic interactions and food web stability. Recognizing the sublethal impacts of neonicotinoids is critical for the development of more sustainable pest management strategies. It is imperative that future research investigates the underlying mechanisms of sublethal toxicity and identifies safer, more effective approaches to neonicotinoid-based pest control to mitigate adverse ecological effects. Incorporating this knowledge into future environmental risk assessments will be essential for protecting biodiversity and maintaining ecosystem functionality. Full article

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

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9 pages, 1458 KB

Open AccessArticle

Simulated Heatwaves Affect Development of Two Congeneric Gregarious Larval–Pupal Endoparasitoids

by Lizhi Wang, Yanli Zhao, Zhihui Jiao, Baoping Li and Minghui Fei

Insects 2026, 17(1), 25; https://doi.org/10.3390/insects17010025 - 24 Dec 2025

Abstract

Ongoing climate change is increasing the frequency and magnitude of high-temperature events, and extreme weather events such as heatwaves are expected to become more common. The impacts of extreme temperatures are likely even more severe at higher trophic levels, which depend on the [...] Read more.

Ongoing climate change is increasing the frequency and magnitude of high-temperature events, and extreme weather events such as heatwaves are expected to become more common. The impacts of extreme temperatures are likely even more severe at higher trophic levels, which depend on the adaptive capacity of lower trophic levels. However, compared with parasitoids at the third trophic level, less is known about these effects on parasitoids at the fourth trophic level, which occupy the terminal end of food chains. This study investigates the effects of experimental heatwave duration variability on the development of two congeneric gregarious larval–pupal endoparasitoids, Oomyzus scaposus and O. spiraculus, parasitizing the seven-spot ladybird, Coccinella septempunctata L. Heatwave treatments negatively affected the brood size of both species. The heatwave also affected the sex ratio of O. scaposus, though it remained highly female-biased. Exposure to heatwaves for 1 h accelerated the development of O. scaposus. For O. scaposus, the body mass of both females and males was lowest under the 3 h heatwave treatment. In contrast, for O. spiraculus, heatwaves had a marginally negative effect on the body mass of both female and male adults, though this effect was not statistically significant. Our results indicate that both species respond similarly, and even daily heatwave exposure of a few hours can affect the performance of O. scaposus and O. spiraculus. Full article

(This article belongs to the Special Issue Host Specificity of Parasitoid Wasps and Its Applications in Biological Control)

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15 pages, 10940 KB

Open AccessCommunication

Effectiveness of Repellent Plants for Controlling Potato Tuber Moth (Symmetrischema tangolias) in the Andean Highlands

by Alex Villanueva, Fernando Escobal, Héctor Cabrera, Héctor Cántaro-Segura, Luis Diaz-Morales and Daniel Matsusaka

Insects 2026, 17(1), 24; https://doi.org/10.3390/insects17010024 - 24 Dec 2025

Abstract

Postharvest losses from potato tuber moth severely constrain seed quality in Andean smallholder systems. This study evaluated four locally available repellent plants—Ambrosia peruviana, Eucalyptus globulus, Artemisia absinthium, and Minthostachys mollis—applied as dried leaves layered within seed bags of [...] Read more.

Postharvest losses from potato tuber moth severely constrain seed quality in Andean smallholder systems. This study evaluated four locally available repellent plants—Ambrosia peruviana, Eucalyptus globulus, Artemisia absinthium, and Minthostachys mollis—applied as dried leaves layered within seed bags of INIA 302 ‘Amarilis’ under farmer-like storage at two highland sites in Cajamarca, Peru (Huaytorco, 3350 m; Samaday, 2750 m), over 187 days. Within each site, a Completely Randomized Design with three bag-level replicates per treatment was used, and damage was assessed after 187 days as incidence of attacked tubers, internal damage severity and live larval counts. Endpoint data were analyzed separately by site using Kruskal–Wallis tests followed by Dunn’s post hoc test with Šidák correction (α = 0.05). Across both sites, all botanicals significantly reduced damage severity and live larval counts relative to the untreated control. At the warmer, lower site, A. absinthium and M. verticillata achieved large effect sizes, with severity and larval numbers reduced by roughly 80–90% compared with the control, while at the cooler, higher site, larvae were not detected in any botanical treatment. These findings indicate that simple layering of dried leaves from locally available plants, particularly wormwood and muña, can substantially mitigate S. tangolias damage in highland seed potato stores and represents a promising, low-cost complement to integrated pest management, although multi-season and dose-response studies are still needed to confirm and refine this approach. Full article

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

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