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Insects, Volume 16, Issue 6 (June 2025) – 92 articles

Cover Story (view full-size image): Drosophila subobscura is a species that stands out for its large chromosomal inversion polymorphism that affects its five long chromosomes. Investigations into natural populations have revealed that its inversion polymorphism has adaptive properties. In this work, we localize the breakpoints of inversions U6 and U8 as a first approach to candidate genes in the inversions that may be affected by selection. Interestingly, our results suggest that the origin of both inversions could have been mediated by transposons, and, in the case of U8, we found a new fold-back-type element characteristic of the subobscura species group that we have designated Ziga-ZagaView this paper
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22 pages, 3591 KiB  
Article
Trends and Emerging Hotspots in Toxicology of Chironomids: A Comprehensive Bibliometric Analysis
by Wen-Bin Liu, Wen-Xuan Pei, Zi-Ming Shao, Jia-Xin Nie, Wei Cao and Chun-Cai Yan
Insects 2025, 16(6), 639; https://doi.org/10.3390/insects16060639 - 17 Jun 2025
Abstract
(1) Background: Aquatic organisms are more sensitive to pollutants than terrestrial ones, making them ideal for ecotoxicology studies. Chironomids, a key bioindicator species, have been widely used in environmental pollution research. With the continuous deepening of research on water environmental pollution and the [...] Read more.
(1) Background: Aquatic organisms are more sensitive to pollutants than terrestrial ones, making them ideal for ecotoxicology studies. Chironomids, a key bioindicator species, have been widely used in environmental pollution research. With the continuous deepening of research on water environmental pollution and the continuous development of molecular biology, it is therefore very important to understand the current research progress of the toxicology of chironomids. (2) Methods: This study used bibliometrics to analyze 1465 publications on chironomid toxicology from the Web of Science and PubMed databases, aiming to reveal research trends, hotspots, and future directions. The data analysis involved Microsoft Excel, VOS viewer, CiteSpace, and ChatGLM. (3) Results: Heavy metals, pesticides, and microplastics were the main pollutants studied, with Chironomus riparius being the most researched species. The analysis indicated a growing research trend since 1998, reflecting an increasing global concern over aquatic pollution. This study concludes that more molecular-level research is needed to uncover toxic mechanisms and improve environmental risk assessments. (4) Conclusions: This work will aid scientists and policymakers in developing better pollution control strategies and conservation efforts for aquatic ecosystems, ultimately contributing to environmental protection and public health. Full article
(This article belongs to the Section Other Arthropods and General Topics)
29 pages, 7911 KiB  
Article
The Dysregulation of Tuning Receptors and Transcription Factors in the Antennae of Orco and Ir8a Mutants in Aedes aegypti Suggests a Chemoreceptor Regulatory Mechanism Involving the MMB/dREAM Complex
by Matthew M. Cooke, Michael S. Chembars II and Ronald Jason Pitts
Insects 2025, 16(6), 638; https://doi.org/10.3390/insects16060638 - 17 Jun 2025
Abstract
Olfaction has been extensively studied in the yellow fever mosquito, Aedes aegypti. This species uses its sense of smell to find blood hosts and other resources, contributing to its impact as a vector for human pathogens. Two major families of protein-coding genes, [...] Read more.
Olfaction has been extensively studied in the yellow fever mosquito, Aedes aegypti. This species uses its sense of smell to find blood hosts and other resources, contributing to its impact as a vector for human pathogens. Two major families of protein-coding genes, the odorant receptors (Ors) and the ionotropic receptors (Irs), provide the mosquito with sensitivities to distinct classes of volatile compounds in the antennae. Individual tuning receptors in both families require co-receptors for functionality: Orco for all Ors, and Ir8a for many Irs, especially ones that are involved in carboxylic acid detection. In Drosophila melanogaster, disruptions of Orco or Ir8a impair receptor function, tuning receptor expression, and membrane localization, leading to general anosmia. We reasoned that Orco and Ir8a might also be important for coordinated chemosensory receptor expression in the antennal sensory neurons of Ae. aegypti. To test this, we performed RNAseq and differential expression analysis in wildtype versus Orco−/− and Ir8a−/− mutant adult female antennae. Our analyses revealed Or and Ir tuning receptors are broadly under-expressed in Orco−/− mutants, while a subset of tuning Irs are under-expressed in Ir8a mutants. Other chemosensory and non-chemosensory genes are also dysregulated in these mutants. Furthermore, we identify differentially expressed transcription factors including homologs of the Drosophila melanogaster Mip120 gene. These data suggest a previously unknown pleiotropic role for the Orco and Ir8a co-receptors in the coordination of expression of chemosensory receptors within the antennae of Ae. aegypti by participating in a feedback loop involving amos and members of the MMB/dREAM complex. Full article
(This article belongs to the Section Insect Molecular Biology and Genomics)
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15 pages, 1480 KiB  
Article
Development of a New Trapping System with Potential Implementation as a Tool for Mosquito-Borne Arbovirus Surveillance
by Luísa Maria Inácio da Silva, Larissa Krokovsky, Rafaela Cassiano Matos, Gabriel da Luz Wallau and Marcelo Henrique Santos Paiva
Insects 2025, 16(6), 637; https://doi.org/10.3390/insects16060637 - 17 Jun 2025
Abstract
Mosquitoes of the Aedes and Culex genera are primary vectors of arboviruses such as the dengue, Zika, chikungunya (CHIKV), Oropouche, and West Nile viruses, causing millions of infections annually. Standard virus detection in mosquitoes requires capturing, transporting, and processing samples with a cold [...] Read more.
Mosquitoes of the Aedes and Culex genera are primary vectors of arboviruses such as the dengue, Zika, chikungunya (CHIKV), Oropouche, and West Nile viruses, causing millions of infections annually. Standard virus detection in mosquitoes requires capturing, transporting, and processing samples with a cold chain to preserve RNA, which is challenging in resource-limited areas. FTA cards preserve viral RNA at room temperature and have been used to collect mosquito saliva, a key sample for assessing transmission. However, most FTA-based traps require electricity or CO2, limiting use in low-resource settings. This study adapted and evaluated the BR-ArboTrap, a low-cost trap derived from an oviposition trap, integrating a sugar-based attractant with FTA cards to collect mosquito saliva, without electricity or refrigeration. Aedes aegypti exposed to CHIKV were used in three experiments to evaluate: (i) RNA preservation under different conditions, (ii) the minimum number of positive mosquitoes for detection, and (iii) RNA amounts on FTA versus blood. RT-qPCR detected CHIKV RNA in 90% of FTA cards and 96% of exposed mosquitoes. RNA remained stable under varying conditions, with no significant difference compared to blood. BR-ArboTrap is an effective, affordable, and field-ready tool to enhance arbovirus surveillance in remote and low-resource areas. Full article
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27 pages, 12102 KiB  
Article
Genome Annotation of Molting-Related Protein-Coding Genes in Propsilocerus akamusi Reveals Transcriptomic Responses to Heavy Metal Contamination
by Wenbin Liu, Anmo Zhou, Ziming Shao, Jiaxin Nie, Chuncai Yan, Shaobo Gao and Yiwen Wang
Insects 2025, 16(6), 636; https://doi.org/10.3390/insects16060636 - 17 Jun 2025
Abstract
The exoskeleton of insects, known as the cuticle, necessitates regular renewal during molting and metamorphosis, with chitin being its primary structural component. Consequently, the molting and metamorphosis processes in insects are characterized by periodic degradation and synthesis of chitin, which are tightly regulated [...] Read more.
The exoskeleton of insects, known as the cuticle, necessitates regular renewal during molting and metamorphosis, with chitin being its primary structural component. Consequently, the molting and metamorphosis processes in insects are characterized by periodic degradation and synthesis of chitin, which are tightly regulated by juvenile hormone (JH) and 20-hydroxyecdysone (20E). Propsilocerus akamusi, a species that plays a crucial role in freshwater ecosystems, demonstrates remarkable resilience to environmental pollutants, including metallic elements found in industrial waste. In this investigation, we systematically analyzed and summarized the metabolic pathways associated with JH, 20E, chitin, and heavy metal transport in P. akamusi. Based on previous genome assembly, we conducted a systematic annotation and functional analysis of genes involved in these metabolic pathways in P. akamusi. This was achieved by querying conserved domains using Pfam and SMART, as well as identifying gene-specific classical consensus regions through amino acid sequence alignment using DNAMAN. Through our validation, a total of 109 genes were definitively categorized into four distinct metabolic pathways: 27 genes were involved in the JH metabolic pathway, 24 in the 20E metabolic pathway, 27 in the chitin metabolic pathway, and 31 in metal transport pathways. A total of 30 genes failed our validation and were temporarily excluded. Furthermore, through RNA sequencing (RNA-seq)-based transcriptome analysis, we observed that under copper (Cu) stress, the expression levels of the majority of genes participating in these metabolic pathways in P. akamusi were altered. This finding suggests that copper exposure influences the molting process in P. akamusi. Full article
(This article belongs to the Special Issue Aquatic Insects Biodiversity and eDNA Monitoring)
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13 pages, 845 KiB  
Article
Low-Temperature Phosphine Fumigation Is Effective Against Drosophila suzukii in Sweet Cherry
by Hang Zou, Li Li, Jun Zhang, Baishu Li, Yu Xiao, Yonglin Ren, Ju Huang, Wei Chen and Tao Liu
Insects 2025, 16(6), 635; https://doi.org/10.3390/insects16060635 - 17 Jun 2025
Abstract
Drosophila suzukii, classified as a quarantine pest in some countries, poses a serious threat to global trade due to its ability to damage berries and cherries. Recent studies indicate that low-temperature phosphine (PH3) fumigation effectively controls this pest without compromising [...] Read more.
Drosophila suzukii, classified as a quarantine pest in some countries, poses a serious threat to global trade due to its ability to damage berries and cherries. Recent studies indicate that low-temperature phosphine (PH3) fumigation effectively controls this pest without compromising fresh produce quality. However, the specific protocol for managing D. suzukii larvae in cherries using this method remains underexplored. This study evaluates the efficacy of low-temperature PH3 fumigation in controlling D. suzukii larvae across three cherry varieties at 3 °C and investigates potential effects on key quality metrics. Tolerance assessments revealed that 3rd instar larvae exhibit the highest resistance to PH3 among all developmental stages. A concentration of 800 mL/m3 PH3 for 84 h at 3 °C achieved phytosanitary efficacy for 0.99997 with no negative effect on the quality attributes of the tested cherry varieties. These results support low-temperature PH3 fumigation as a viable postharvest treatment for D. suzukii management in sweet cherries. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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18 pages, 2663 KiB  
Article
Functional Differentiation Reconfiguration in the Midgut of Nezara viridula (Hemiptera: Pentatomidae) Based on Transcriptomics: Multilayer Enrichment Analysis and Topological Network Interpretation
by Dongyue Yu, Jingyu Liang and Wenjun Bu
Insects 2025, 16(6), 634; https://doi.org/10.3390/insects16060634 - 16 Jun 2025
Abstract
The present investigation systematically elucidates the distinct functional specialization within the M1–M3 midgut sections of the significant agricultural pest, Nezara viridula. Employing an integrated transcriptomic analysis, three pivotal discoveries were achieved: (1) each midgut segment possesses unique gene expression signatures; (2) metabolic [...] Read more.
The present investigation systematically elucidates the distinct functional specialization within the M1–M3 midgut sections of the significant agricultural pest, Nezara viridula. Employing an integrated transcriptomic analysis, three pivotal discoveries were achieved: (1) each midgut segment possesses unique gene expression signatures; (2) metabolic and signal transduction pathways exhibit coordinated regulatory patterns; and (3) parallel expression changes occur between neuroreceptor (e.g., TACR/HTR) and metabolic enzyme (e.g., GLA/NAGA) genes within identical midgut segments. These data reveal that the M1 region is primarily enriched in metabolic processes and neural signaling; the M2 region emphasizes cellular junctions and immune responses, while the M3 region is mainly responsible for cellular senescence and renewal. These discoveries advance the understanding of feeding adaptation mechanisms in Hemipteran insects and propose a “metabolism–defense–regeneration” functional model for the midgut. The established multi-level analytical framework provides a robust methodology for subsequent dissection of complex biological systems, identification of key molecular targets for functional validation, and for the development of novel pest control strategies. Full article
(This article belongs to the Section Insect Molecular Biology and Genomics)
13 pages, 1288 KiB  
Article
Electrophysiological and Behavioral Responses of Thrips hawaiiensis (Thysanoptera: Thripidae) to the Floral Volatiles of the Horticultural Plant Magnolia grandiflora (Magnoliales: Magnoliaceae)
by Tao Zhang, Yuping Yang, Filippo Maggi, Feiyu Jiang, Rongrong Yuan, Lujie Huang, Xueyan Zhang, Yu Cao and Yulin Gao
Insects 2025, 16(6), 633; https://doi.org/10.3390/insects16060633 - 16 Jun 2025
Abstract
Volatile cues are important in the host detection and discrimination of phytophagous insects, allowing them to find suitable hosts. Here, the electroantennography (EAG) and behavioral responses of female Thrips hawaiiensis to the floral volatiles of different plants, Magnolia grandiflora L. (Magnoliales: Magnoliaceae), Gerbera [...] Read more.
Volatile cues are important in the host detection and discrimination of phytophagous insects, allowing them to find suitable hosts. Here, the electroantennography (EAG) and behavioral responses of female Thrips hawaiiensis to the floral volatiles of different plants, Magnolia grandiflora L. (Magnoliales: Magnoliaceae), Gerbera jamesonii Bolus (Asterales: Asteraceae), Lilium brownii Baker (Liliales: Liliaceae), and Rosa rugosa Thunb. (Rosales: Rosaceae), were studied. Y-tube olfactometer bioassays revealed that M. grandiflora was the preferred host for T. hawaiiensis. Fifty-two compounds were identified from the volatile profile of M. grandiflora by gas chromatography–mass spectrometry analysis, of which β-elemen (15.39%), bicyclogermacren (11.99%), and (E)-α-bisabolene (6.05%) showed the highest relative contents. The EAG bioassays revealed that the antennae of T. hawaiiensis could perceive these tested volatile compounds at different concentrations. In six-arm olfactometer bioassays, T. hawaiiensis showed significant positive responses to β-elemen and (E)-α-bisabolene at various concentrations, and 10 μg/μL was found to be the most attractive concentration for β-elemen, and 50 and 100 μg/μL for (E)-α-bisabolene. Based on the four-arm olfactometer bioassays, β-elemen was more attractive than (E)-α-bisabolene to T. hawaiiensis when compared at their optimal concentrations. Therefore, T. hawaiiensis could perceive and distinguish the floral volatiles from the preferred host plant (M. grandiflora). These findings assist in better understanding the mechanism of host preferences of T. hawaiiensis from a chemoecological perspective. In particular, β-elemen showed the greatest potential to be developed as a novel attractant for the monitoring and control of T. hawaiiensis. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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22 pages, 2827 KiB  
Article
Invertebrates of Siberia, a Potential Source of Animal Protein for Innovative Food and Feed Production: Biomass Nutrient Composition Change in the Earthworm Eisenia fetida (Savigny, 1826) and the House Cricket Acheta domesticus (Linnaeus, 1758)
by Sergei E. Tshernyshev, Andrei S. Babenko, Irina B. Babkina, Ruslan T.-O. Baghirov, Vera P. Modyaeva, Margarita D. Morozova, Ksenia E. Skribtcova, Elena Y. Subbotina, Mikhail V. Shcherbakov and Anastasia V. Simakova
Insects 2025, 16(6), 632; https://doi.org/10.3390/insects16060632 - 16 Jun 2025
Abstract
The possibility of designing the nutrient composition of invertebrate biomass was investigated. Two model species of terrestrial invertebrates, the house cricket Acheta domesticus (Linnaeus, 1758) and the earthworm Eisenia fetida (Savigny, 1826), were studied after feeding on substrates alternately enriched with certain nutrient [...] Read more.
The possibility of designing the nutrient composition of invertebrate biomass was investigated. Two model species of terrestrial invertebrates, the house cricket Acheta domesticus (Linnaeus, 1758) and the earthworm Eisenia fetida (Savigny, 1826), were studied after feeding on substrates alternately enriched with certain nutrient precursors proposed in single and double doses. Crickets and earthworms showed similar tendencies to increase the B vitamin content of those vitamins whose initial level was high. Double-dose enrichment of the food substrate increased the levels of vitamin C, fat-soluble vitamins and most B vitamins. In a control group of crickets, vitamin C levels were 1.5 times lower than in a control group of earthworms. After enrichment of the feed substrate, the vitamin C content in the biomass of the crickets did not change significantly, but in the earthworms it increased significantly. The content of a wide range of minerals did not change after single-dose enrichment, but some micro-elements such as Pb and Se decreased significantly in earthworms after double-dose enrichment of the feed substrate. The calorific value of crickets was twice that of earthworms and did not change significantly after double-dose enrichment. It is shown that the nutrient composition of invertebrate biomass can be increased by enriching the feed substrate with precursors. The most effective increases are observed for all vitamins and several minerals. The results can be used to achieve specific nutrient concentrations in biomass for food and medical purposes. Full article
(This article belongs to the Special Issue Insects as the Nutrition Source in Animal Feed)
17 pages, 1640 KiB  
Article
Time to Emergence of the Lyme Disease Pathogen in Habitats of the Northeastern U.S.A.
by Dorothy Wallace, Michael Palace, Lucas Eli Price and Xun Shi
Insects 2025, 16(6), 631; https://doi.org/10.3390/insects16060631 - 16 Jun 2025
Abstract
Ticks carry a range of pathogens, the best known of which causes Lyme disease, prevalent in the northeastern United States. Emerging diseases do not yet consist of a wide range of Lyme diseases, raising the question of how long it takes for a [...] Read more.
Ticks carry a range of pathogens, the best known of which causes Lyme disease, prevalent in the northeastern United States. Emerging diseases do not yet consist of a wide range of Lyme diseases, raising the question of how long it takes for a newly introduced tick-borne disease to establish itself. The aim of this study was to address this question, with the agent of Lyme disease used as the test case. A prior process-based model of the Ixodes scapularis (Say 1821) life cycle and the transmission of Borrelia burgdorferi (Burgdorfer 1982) between this tick and its various hosts was used to predict the dynamics of disease introduction into a new area. The importance of temperature, infection probabilities, and tick host populations, relative to that of other factors, was established by a global sensitivity analysis using Latin hypercube sampling. The results of those samples were analyzed to determine the time to near-equilibrium. Eight locations in New Hampshire were chosen for high/low temperature, high/low mouse, and high/low deer values. Mammal abundance was estimated by relating the known mammal density from previous studies to a MaxEnt analysis output. The time required to reach Borrelia endemicity in the ticks of New Hampshire ranged from 8 to 20 years in regions where the tick population is viable, with a strong dependency on susceptible tick host populations. Full article
(This article belongs to the Section Medical and Livestock Entomology)
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13 pages, 1115 KiB  
Article
Spatial Distribution Characteristics and Driving Factors of Formicidae in Small Watersheds of Loess Hilly Regions
by Yu Tian, Fangfang Qiang, Guangquan Liu, Changhai Liu and Ning Ai
Insects 2025, 16(6), 630; https://doi.org/10.3390/insects16060630 - 15 Jun 2025
Viewed by 47
Abstract
This study takes the Jinfoping Small Watershed in the Loess Hilly Region as the research area. Through field investigation and laboratory analysis, combined with methods such as spatial autocorrelation analysis, the ordinary least squares method (OLS), and the geographically weighted regression model (GWR), [...] Read more.
This study takes the Jinfoping Small Watershed in the Loess Hilly Region as the research area. Through field investigation and laboratory analysis, combined with methods such as spatial autocorrelation analysis, the ordinary least squares method (OLS), and the geographically weighted regression model (GWR), it deeply explores the spatial distribution characteristics and driving factors of Formicidae in the study area. The research results are as follows: (1) Spatial autocorrelation analysis indicates that the distribution of Formicidae is significantly regulated by spatial dependence and has significant spatial autocorrelation (global Moran’s I = 0.332; p < 0.01). (2) The spatial visualization analysis of the GWR model reveals that soil physical and chemical properties and topographic factors have local influences on the spatial distribution of Formicidae. Available phosphorus (AP) and slope (SLP) were significantly positively correlated with the number of ants. Hydrogen peroxidase (HP) and topographic relief (TR) were significantly negatively correlated with the number of ants. This study reveals the spatial distribution pattern of Formicidae in the Loess Hilly Region and its complex relationship with environmental factors, and clarifies the importance of considering spatial heterogeneity when analyzing ecosystem processes. The research results provide a scientific basis for the protection and management of soil ecosystems, and also offer new methods and ideas for future related research. Full article
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15 pages, 1849 KiB  
Article
Sublethal Effects of Abamectin and Acetamiprid on the Longevity, Fecundity and Detoxification Enzyme Activity of Rhopalosiphum padi
by Bokun Wang, Hongming Hui, Xingye Li, Xueqing Yang and Yuting Li
Insects 2025, 16(6), 629; https://doi.org/10.3390/insects16060629 - 15 Jun 2025
Viewed by 41
Abstract
The bird cherry-oat aphid Rhopalosiphum padi (L.) poses a significant threat to wheat production, resulting in substantial yield reductions. Abamectin and acetamiprid are frequently utilized for management. This study assessed the sublethal effects of abamectin and acetamiprid on R. padi through life table [...] Read more.
The bird cherry-oat aphid Rhopalosiphum padi (L.) poses a significant threat to wheat production, resulting in substantial yield reductions. Abamectin and acetamiprid are frequently utilized for management. This study assessed the sublethal effects of abamectin and acetamiprid on R. padi through life table analysis and enzyme activity assays. At 24 h, the LC10 and LC30 values for abamectin to R. padi were 0.063 mg/L and 0.252 mg/L, respectively, while, for acetamiprid, the corresponding values were 0.065 and 0.293 mg/L. The results indicated that exposure to sublethal concentrations of abamectin (AB-LC10) extended the longevity of R. padi F0 generation, while acetamiprid (AC-LC10 and AC-LC30) decreased it. Furthermore, the fecundity of the F0 generation was significantly reduced following exposure to AB-LC30, AC-LC10 and AC-LC30. In the F1 generation, exposure to sublethal concentrations of acetamiprid negatively impacted on R. padi, as evidenced by a significant reduction in longevity; fecundity and population parameters (R0, r, λ, sxj, lx, lxmx, vxj and exj). Conversely, sublethal concentrations of abamectin did not significantly affect these parameters. Additionally, population projections revealed a significantly smaller total population size of R. padi in the acetamiprid-exposed group compared to both the abamectin-exposed and control groups. Except these population-level effects, the activities of detoxification enzymes, including cytochrome P450 monooxygenases (P450), glutathione S-transferases (GST) and carboxylesterases (CarE), changed differently after treatments. These results suggest that sublethal concentrations of acetamiprid, but not abamectin, significantly inhibit the population growth of R. padi. These insights are crucial for R. padi control and facilitate the development of effective control strategies that take into account these sublethal effects in integrated pest management strategies targeting R. padi. Full article
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17 pages, 1232 KiB  
Article
Wohlfahrtia nuba (Wiedemann, 1830) (Diptera: Sarcophagidae) Development and Survival Under Fluctuating Temperatures
by Abeer S. Yamany, Manal F. Elkhadragy and Rewaida Abdel-Gaber
Insects 2025, 16(6), 628; https://doi.org/10.3390/insects16060628 - 13 Jun 2025
Viewed by 119
Abstract
The flesh fly, Wohlfahrtia nuba (Wiedemann) (Diptera: Sarcophagidae), is one of the first necrophagous insects to arrive on a cadaver and is vital for understanding decomposition. Environmental factors, especially temperature, influence insect development, which is crucial for estimating postmortem interval (PMI) in forensic [...] Read more.
The flesh fly, Wohlfahrtia nuba (Wiedemann) (Diptera: Sarcophagidae), is one of the first necrophagous insects to arrive on a cadaver and is vital for understanding decomposition. Environmental factors, especially temperature, influence insect development, which is crucial for estimating postmortem interval (PMI) in forensic entomology. This study explored how seasonal temperature variations affect the survival and development of W. nuba’s immature stages. The W. nuba colony was reared in the laboratory for four seasons from 3 October 2023 to 30 September 2024. The duration of the larval and pupal phases, the percentage of survival and mortality of the larvae and pupae, the larval growth rate, the percentage of emergence, fecundity, the sex ratio, and the pre-larviposition period were among the many life cycle characteristics that were documented during the study. Research indicates that seasonal changes affect development, shortening the growth period as temperatures rise. Flies raised at an average temperature of 38.3 °C grew faster but experienced higher larval mortality and lower survival rates. The average duration of larval and pupal stages was reduced, with an optimal development temperature of 27.9 °C showing higher survival rates, maximum body weight, and fecundity. The largest mortality rate occurred during winter at an average temperature of 18.5 °C, with males and females showing significant pupal elongation. The findings could help forensic entomologists working on legal investigations to ascertain PMI. Full article
(This article belongs to the Section Insect Physiology, Reproduction and Development)
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14 pages, 5097 KiB  
Article
Potentially Suitable Habitat for the Pest Histia rhodope Based on Its Host Plant Bischofia polycarpa and Climatic Factors in China
by Huicong Du, Jingxin Shen, Wenping Luo, Zi Yang, Daizhen Zhang and Xiangbo Kong
Insects 2025, 16(6), 627; https://doi.org/10.3390/insects16060627 - 13 Jun 2025
Viewed by 141
Abstract
Histia rhodope is a defoliating pest that feeds mainly on the ornamental garden plant Bischofia polycarpa. Recently, frequent outbreaks of H. rhodope in Southern China have severely affected cityscapes and people’s lives. To provide a predictive early-warning program for the spread risk [...] Read more.
Histia rhodope is a defoliating pest that feeds mainly on the ornamental garden plant Bischofia polycarpa. Recently, frequent outbreaks of H. rhodope in Southern China have severely affected cityscapes and people’s lives. To provide a predictive early-warning program for the spread risk of H. rhodope in China and reduce damage to B. polycarpa, we used the MaxEnt model to investigate the potentially suitable spread characteristics of H. rhodope and its host B. polycarpa under different climate scenarios for the years 2050 and 2070. The results showed that the potentially suitable habitat of H. rhodope under the SSP5-8.5 scenario will reach an area of 3174.55 × 103 km2 in the 2070s, an increase of 1010 × 103 km2 from the current distribution. The potentially suitable habitat of B. polycarpa under the SSP5-8.5 scenario will reach 2618.01 × 103 km2 in the 2070s (an increase of 464 × 103 km2). The potentially suitable habitats of H. rhodope and B. polycarpa are expected to shift to higher elevations under future climate scenarios. We also identified ten key environmental factors, of which Precipitation of Warmest Quarter (bio18) had the greatest influence on the probability of moth and host plant occurrence. Our results highlight the risk of further expansion of the potentially suitable area for H. rhodope and the important role of the host plant in this process, and provide a firm scientific basis for the monitoring and management of H. rhodope and B. polycarpa. Full article
(This article belongs to the Special Issue Effects of Environment and Food Stress on Insect Population)
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14 pages, 3023 KiB  
Article
Distribution Pattern and Change Prediction of Luprops orientalis (Coleoptera: Tenebrionidae) Suitable Area in East Asia Under Climate Change
by Jieqiong Wang, Shuangyi Wang, Yunchun Li, Shuangmei Ding, Zhonghua Wei, Aimin Shi and Ding Yang
Insects 2025, 16(6), 626; https://doi.org/10.3390/insects16060626 - 13 Jun 2025
Viewed by 132
Abstract
Luprops orientalis (Motschulsky, 1868) is an economically important pest in traditional Chinese medicines, widely distributed in East Asia. However, the primary limiting factors affecting its distribution, potential suitable areas, as well as its response to global warming, remain largely unknown. Utilizing 295 filtered [...] Read more.
Luprops orientalis (Motschulsky, 1868) is an economically important pest in traditional Chinese medicines, widely distributed in East Asia. However, the primary limiting factors affecting its distribution, potential suitable areas, as well as its response to global warming, remain largely unknown. Utilizing 295 filtered distribution points and 10 environmental variables (9 climate variables and 1 land cover type), this study uses the MaxEnt model to predict the potential distribution of L. orientalis under near-current and future environmental change scenarios. The results indicated that precipitation of the warmest quarter (bio18), temperature seasonality (bio04), and precipitation of the wettest month (bio13) were the most significant environmental variables affecting the distribution of suitable habitats for L. orientalis, while the contribution of average variation in daytime temperature (bio2) was the smallest. Under the near-current climate, the areas of low, moderate, and high suitability for L. orientalis are approximately 1.02 × 106 km2, 1.65 × 106 km2, and 8.22 × 105 km2, respectively. The suitable areas are primarily located in North China, Central China, the Korean Peninsula, and Central and Southern Japan. Under future climate conditions, the potential suitable areas are expected to expand significantly, especially in Central China. However, the high-suitability areas in North China are predicted to experience a slight reduction. With the increase in carbon emission concentrations, the suitable area shows an increasing trend in the 2050s, followed by a declining trend in the 2090s. The centroids of suitable areas will shift to the northeast in the future. These findings enhance our understanding of how climate change affects the distribution of L. orientalis and will assist governments in formulating effective pest control strategies, including widespread monitoring and stringent quarantine measures. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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24 pages, 14728 KiB  
Article
Death-Leading Envenomization of Rabbits with Snake Versus Scorpion Venoms: A Comparative Forensic Investigation of Postmortem Decomposition and Beetle Succession
by Afnan Saleh Al-Qurashi, Mohammed Saleh Al-Khalifa, Hathal Mohammed Al Dhafer, Mahmoud Saleh Abdel-Dayem, Hossam Ebaid and Ashraf Mohamed Ahmed
Insects 2025, 16(6), 625; https://doi.org/10.3390/insects16060625 - 13 Jun 2025
Viewed by 184
Abstract
Background:Envenomation by poisonous creatures is a major global cause of mortality. Its concomitant impact on the postmortem corpse decomposition and associated insect succession pattern is still poorly understood. Purpose of the study: This study comparatively investigates the impact of envenomization with [...] Read more.
Background:Envenomation by poisonous creatures is a major global cause of mortality. Its concomitant impact on the postmortem corpse decomposition and associated insect succession pattern is still poorly understood. Purpose of the study: This study comparatively investigates the impact of envenomization with the venoms of the snake Walterinnesia aegyptia L. versus the scorpion, Androctonus crassicauda L., on rabbit corpse decomposition and beetle succession. Methods: Three groups of rabbits (five animals each) were injected with the snake venom, the scorpion venom, or 0.9% saline (control) prior to euthanasia with CO2. The corpse decomposition stages and beetle succession were monitored over 11 days. Results: Four stages of decomposition with venom-dependent duration variation were observed. The scorpion-envenomized corpses showed a longer decay stage and a delayed dry stage. A total of 1094 beetles belonging to 27 species of 14 families were reported. Histeridae, Dermestidae, Scarabaeidae, and Tenebrionidae were the most diversified and prevalent families. Chrysomelidae, Elateridae, Hybosoridae, and Ptinidae were incidentally attracted to control corpses, while Nitidulidae and Zopheridae were only found on control and snake-envenomized ones. Four species belonging to the families Anthicidae, Histeridae, Scarabaeidae, and Tenebrionidae were predominant on all corpses. Four species belonging to the families Chrysomelidae, Curculionidae, Elateridae, and Hybosoridae were distinctively associated with the control corpses. Conclusions: These findings provided evidence that envenomation impacted the decomposition process and beetle succession in a venom-dependent manner, which could be significant for forensic investigations. Full article
(This article belongs to the Section Role of Insects in Human Society)
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17 pages, 2226 KiB  
Article
Transcriptome-Wide Identification of Neuropeptides and Neuropeptide Receptors in the Twenty-Eight-Spotted Ladybird Henosepilachna vigintioctopunctata
by Quanxing Lei, Ziming Wang, Shuangyan Yao, Aili Lin, Yunhui Zhang, Chengxian Sun, Xiaoguang Liu, Mengfang Du, Xiaoming Liu and Shiheng An
Insects 2025, 16(6), 624; https://doi.org/10.3390/insects16060624 - 13 Jun 2025
Viewed by 189
Abstract
The ladybird beetle, Henosepilachna vigintioctopunctata, is an oligophagous pest with significant economic impact. This pest causes considerable economic damage on numerous Solanaceae crops. Neuropeptides, along with their designated receptors, play a pivotal role in regulating diverse biological processes in insects, presenting a [...] Read more.
The ladybird beetle, Henosepilachna vigintioctopunctata, is an oligophagous pest with significant economic impact. This pest causes considerable economic damage on numerous Solanaceae crops. Neuropeptides, along with their designated receptors, play a pivotal role in regulating diverse biological processes in insects, presenting a promising avenue for innovative pest management strategies. Herein, the transcriptome of the central nervous system (CNS) of H. vigintioctopunctata was sequenced. Overall, our analysis identified 58 neuropeptide precursor genes, from which 98 diverse mature peptides were predicted. Furthermore, 31 neuropeptide receptor genes belonging to three distinct classes were discovered, along with predictions for their potential ligands. Moreover, the expression patterns of these 58 neuropeptide genes across larval brain tissue, ventral nerve cord, and gut were evaluated using quantitative real-time PCR. Collectively, these findings will significantly contribute to future research focused on understanding the physiological functions and pharmacological characteristics of neuropeptides and their receptors in H. vigintioctopunctata. Ultimately, these insights may facilitate the development of targeted neuropeptide-based solutions for managing this pest affecting solanaceous plants. Full article
(This article belongs to the Section Insect Molecular Biology and Genomics)
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15 pages, 4822 KiB  
Article
Predicting the Current and Future Habitat Distribution for an Important Fruit Pest, Grapholita dimorpha Komai (Lepidoptera: Tortricidae), Using an Optimized MaxEnt Model
by Li Huang, Shichao Zuo, Yiqi Huo, Lizong Hu, Zhengbing Wang, Jiahui Zhang, Jin Liu, Weili Ding, Keshi Ma and Mingsheng Yang
Insects 2025, 16(6), 623; https://doi.org/10.3390/insects16060623 - 12 Jun 2025
Viewed by 473
Abstract
The Grapholita dimorpha is one of the significant borer pests that primarily damage plum, pear, and apple trees, often resulting in substantial economic losses in fruit production. However, the potential distribution range of this economically important pest remains poorly understood. In this study, [...] Read more.
The Grapholita dimorpha is one of the significant borer pests that primarily damage plum, pear, and apple trees, often resulting in substantial economic losses in fruit production. However, the potential distribution range of this economically important pest remains poorly understood. In this study, we simulated an optimized maximum entropy (MaxEnt) model to predict the spatiotemporal distribution pattern of G. dimorpha and identified its underlying driving factors. The results indicate that suitable habitats, under current bioclimatic conditions, are mainly distributed in eastern China, northeastern China, Korea, and Japan, covering a total of 273.5 × 104 km2. The highly suitable habitats are primarily located in Korea and parts of central Japan, with a total area of 19.8 × 104 km2. In future projections, the suitable area is expected to increase by 17.74% to 62.10%, and the suitable habitats are predicted to shift northward overall. In particular, there are more highly suitable habitats for G. dimorpha in China and Japan compared to their predominance in Korea under current climatic conditions. The bio9 and bio18 contribute 51.9% and 20.7% to the modeling, respectively, indicating that the distribution of G. dimorpha may be shaped mainly by the mean temperature of the driest quarter and precipitation of the warmest quarter. In summary, the distribution range predicted, particularly for regions with highly suitable habitats, poses a high risk of G. dimorpha outbreaks, emphasizing the priority of pest monitoring and management. Furthermore, the key bioclimatic variables identified could also provide crucial reference for pest monitoring. Full article
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10 pages, 3033 KiB  
Article
Glycosidase Isoforms in Honey and the Honey Bee (Apis mellifera L.): Differentiating Bee- and Yeast-Derived Enzymes and Implications for Honey Authentication
by Ratko Pavlović, Sanja Stojanović, Marija Pavlović, Nenad Drulović, Miroslava Vujčić, Biljana Dojnov and Zoran Vujčić
Insects 2025, 16(6), 622; https://doi.org/10.3390/insects16060622 - 12 Jun 2025
Viewed by 247
Abstract
The enzymes in honey can originate not only from bees and the plants from which the bees collect pollen and nectar but also from feed provided by beekeepers. Enzymes that hydrolyze sucrose—present in honey (α-glucosidase) or honey adulterated with invert syrup (β-fructofuranosidase)—can be [...] Read more.
The enzymes in honey can originate not only from bees and the plants from which the bees collect pollen and nectar but also from feed provided by beekeepers. Enzymes that hydrolyze sucrose—present in honey (α-glucosidase) or honey adulterated with invert syrup (β-fructofuranosidase)—can be distinguished using zymography, where enzymatic bands are detected with nitroblue tetrazolium (NBT) after sugar removal via ultrafiltration. This method enables the identification of honey produced in hives that have been improperly fed with invert syrup, leading to the mixture of natural honey and syrup, and offers a practical tool to detect indirect adulteration. The NBT assay, in combination with ultrafiltration, was used to determine the isoelectric point of honey bee α-glucosidases. The pI value of 6.63 for isoforms found in the head, midgut, and natural honey extracts during winter can be attributed to α-glucosidase III. Two additional isoforms with isoelectric points of 5.20 and 5.77 were observed in the midgut extract and may correspond to α-glucosidase I and II. The difference between α-glucosidase and β-fructofuranosidase was confirmed using a substrate specificity test, followed by thin-layer chromatography, where it was confirmed that α-glucosidase from natural honey, bee head, and bee midgut does not hydrolyze raffinose, in contrast to yeast β-fructofuranosidase. Full article
(This article belongs to the Special Issue Current Advances in Pollinator Insects)
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12 pages, 1087 KiB  
Article
Activation of BmToll9-1 in Silkworm (Bombyx mori) Larval Midgut by Escherichia coli and Regulation of Growth
by Jisheng Liu, Weijian Chen, Minchun Lai, Jiahua Chen and Luc Swevers
Insects 2025, 16(6), 621; https://doi.org/10.3390/insects16060621 - 11 Jun 2025
Viewed by 332
Abstract
Insects rely on their innate immune system to defend against pathogens, and the Toll signaling pathway plays an important role in immune regulation. Our previous studies have shown that BmToll9-1 functions as a positive regulator in the Toll pathway. This study seeks to [...] Read more.
Insects rely on their innate immune system to defend against pathogens, and the Toll signaling pathway plays an important role in immune regulation. Our previous studies have shown that BmToll9-1 functions as a positive regulator in the Toll pathway. This study seeks to elucidate the role of BmToll9-1, as a sensor to bacterial challenge, in modulating larval development and downstream Toll signaling pathways. Silkworm larvae were subjected to infection with either Gram-negative Escherichia coli or Gram-positive Staphylococcus aureus bacteria following silencing of BmToll9-1 by RNA interference (RNAi). This bacterial challenge triggered a compensatory re-induction of BmToll9-1 expression, which resulted in the recovery of larval weight and size to levels observed in untreated controls. Furthermore, upon bacterial infection of BmToll9-1-silenced larvae, there was an up-regulation in the expression of both signaling genes in the Toll pathway and downstream effector genes, with a marked preference for Gram-negative bacteria. These results highlight the involvement of BmToll9-1 in the Toll signaling pathway as a positive regulator, influencing silkworm development. Additionally, BmToll9-1 and BmToll9-2 were cross-validated to be genetically distinct genes, even though they were confirmed to be functionally analogous in the silkworm. Full article
(This article belongs to the Special Issue RNAi in Insect Physiology)
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12 pages, 1284 KiB  
Article
Invasion Dynamics and Migration Patterns of Fall Armyworm (Spodoptera frugiperda) in Shaanxi, China
by Zhanfeng Yan, Xiaojun Feng, Xing Wang, Xiangqun Yuan, Yongjun Zhang, Daibin Yang, Kanglai He, Feizhou Xie, Zhenying Wang and Yiping Li
Insects 2025, 16(6), 620; https://doi.org/10.3390/insects16060620 - 11 Jun 2025
Viewed by 280
Abstract
The fall armyworm (Spodoptera frugiperda) is a highly invasive agricultural pest that has caused significant damage to maize and other crops since its initial detection in China in 2019. Understanding its invasion dynamics, migration patterns, genetic diversity, and overwintering capacity is [...] Read more.
The fall armyworm (Spodoptera frugiperda) is a highly invasive agricultural pest that has caused significant damage to maize and other crops since its initial detection in China in 2019. Understanding its invasion dynamics, migration patterns, genetic diversity, and overwintering capacity is crucial for developing effective pest management strategies. This study investigates these aspects in Shaanxi Province, a critical transitional zone between northern and southern climates in China, from 2019 to 2023. We conducted field surveys in six cities across Shaanxi to monitor the initial infestation of FAW. Migration trajectories were simulated using the HYSPLIT model, integrating pest occurrence data and meteorological information. Genetic analyses were performed on 113 FAW individuals from 12 geographical populations using mitochondrial COI and nuclear Tpi genes. Additionally, an overwintering experiment was conducted to assess the survival of FAW pupae under local winter conditions. The first detection dates of FAW in Shaanxi showed significant interannual variation, with a trend of delayed infestation each year. Three primary migration routes into Shaanxi were identified, originating from Sichuan, Hubei-Chongqing, and Henan. Genetic analysis revealed a predominance of the rice-strain FAW in Shaanxi, with some corn-strain variants in northern regions. The overwintering experiment indicated that FAW pupae could not survive the winter in Shaanxi, suggesting that the region does not support year-round breeding of this pest. This study provides comprehensive insights into the spatiotemporal dynamics and migration patterns of FAW in Shaanxi. The findings highlight the importance of integrated pest management approaches, including monitoring migration routes and genetic diversity, to develop targeted control measures. The inability of FAW to overwinter in Shaanxi suggests that regional climate conditions play a significant role in limiting its year-round presence, which is valuable information for designing early warning systems and sustainable pest management strategies. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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16 pages, 3031 KiB  
Article
Histopathological and Transcriptional Changes in Silkworm Larval Gonads in Response to Chlorfenapyr Exposure
by Tao Li, Changxiong Hu, Zenghu Liu, Qiongyan Li, Yonghui Fan, Pengfei Liao, Min Liu, Weike Yang, Xingxing Li and Zhanpeng Dong
Insects 2025, 16(6), 619; https://doi.org/10.3390/insects16060619 - 11 Jun 2025
Viewed by 352
Abstract
Chlorfenapyr is a widely used insecticide known to harm non-target insects, but its effects on reproductive development in the silkworm (Bombyx mori L.) remain incompletely understood. In this study, we investigated the histopathological and transcriptional changes in the gonads (ovaries and testes) [...] Read more.
Chlorfenapyr is a widely used insecticide known to harm non-target insects, but its effects on reproductive development in the silkworm (Bombyx mori L.) remain incompletely understood. In this study, we investigated the histopathological and transcriptional changes in the gonads (ovaries and testes) of newly molted fifth-instar silkworm larvae exposed to chlorfenapyr. Histopathological analysis revealed delayed gonadal development, a reduction in oogonia and oocytes in the ovaries, and decreased numbers of spermatocytes in the testes. Transcriptome analysis identified significant differentially expressed genes (DEGs), mainly enriched in pathways such as “Drug metabolism—cytochrome P450”, “Insect hormone biosynthesis”, and “Ribosome”. Key up-regulated genes included members of the cytochrome P450 family (CYP6B5, CYP9f2, CYP6B6), glutathione S-transferases (GSTT1, GST1), and juvenile hormone-related enzymes (JHAMT, JHEH), indicating active detoxification and hormonal regulation responses. Several transcription factor families, particularly C2H2, HB-other, and TRAF, exhibited altered expression, suggesting roles in stress adaptation. Protein–protein interaction (PPI) network analysis identified hub genes such as EcR, Kr-h1, and various ribosomal proteins, highlighting their potential involvement in reproductive development. Quantitative PCR (qPCR) validated the transcriptomic data, confirming the reliability of the results. Overall, these findings enhance our understanding of chlorfenapyr’s impact on silkworm reproductive development and the underlying molecular mechanisms, providing valuable insights for sustainable pest management and ecological risk assessment of insecticides. Full article
(This article belongs to the Section Insect Physiology, Reproduction and Development)
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22 pages, 12796 KiB  
Article
The Thoracic Anatomy of Two Flightless Chrysolina Species (Coleoptera: Chrysomelidae)
by Sipei Liu, Xiaokun Liu, Xieshuang Wang, Wenjie Li, Xin Liu and Siqin Ge
Insects 2025, 16(6), 618; https://doi.org/10.3390/insects16060618 - 11 Jun 2025
Viewed by 375
Abstract
Flight loss has independently evolved across nearly all winged insect orders. Comparing the thoracic structures of flightless insects with those of their flight-capable relatives can reveal key characteristics linked with flight. Although flight loss has been widely studied in beetles, exploration of this [...] Read more.
Flight loss has independently evolved across nearly all winged insect orders. Comparing the thoracic structures of flightless insects with those of their flight-capable relatives can reveal key characteristics linked with flight. Although flight loss has been widely studied in beetles, exploration of this phenomenon has been limited to taxonomic and geographic distribution studies in the species-rich family Chrysomelidae, with little analysis of thoracic anatomical structures. This study employs a suite of morphological techniques to examine the thoracic structures of two flightless beetle species Chrysolina: sulcicollis and Chrysolina virgata, originating from desert and temperate regions, respectively. A comparison between the two flightless species reveals that C. sulcicollis has fewer tergo-pleural muscles involved in elytral movement likely to save water, but more muscles that contribute to stabilizing larger body structures. Meanwhile, differences are also observed in the elytral base, the anterior corner of the mesal suture, and the setae on the meso-inner region of the epipleuron. Compared to other flight-capable chrysomelid beetles, apart from the absence of flight-related muscles, the two flightless beetles exhibit similar thoracic skeletal structures. The absence of lateral cervical sclerites, along with the presence of muscles Idvm4, 5 and Itpm5, could enhance head mobility as a compensatory adaptation doe the loss of flight capability. Additionally, the greater number of tergo-pleural muscles in the mesothorax of C. virgata could suggest that its elytra serve a specialized function. Compared to other flightless beetles, aside from the similarly reduced flight muscles, these two species have relatively intact thoracic skeletons. Further data on habitat, functional compensation and other related factors are needed to compare their evolutionary processes with those of other flightless beetles. Full article
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18 pages, 1392 KiB  
Review
Environmental Impacts and Behavioral Adaptations of Honeybees in Algeria: A Review of Apis mellifera intermissa and Apis mellifera sahariensis Characteristics
by Yamina Haider, Noureddine Adjlane and Nizar Haddad
Insects 2025, 16(6), 617; https://doi.org/10.3390/insects16060617 - 11 Jun 2025
Viewed by 338
Abstract
Honeybees are vital for pollination and the overall health of ecosystems. Since the 18th century, the intricate biology of honeybees has been a subject of scientific inquiry. Understanding their biological and behavioral characteristics is essential for effective beekeeping, honey production, and ecosystem sustainability. [...] Read more.
Honeybees are vital for pollination and the overall health of ecosystems. Since the 18th century, the intricate biology of honeybees has been a subject of scientific inquiry. Understanding their biological and behavioral characteristics is essential for effective beekeeping, honey production, and ecosystem sustainability. This review examines the environmental impact and management practices on the health of local honeybees in Algeria, focusing on Apis mellifera intermissa and Apis mellifera sahariensis. We summarize research findings on genetic diversity, morphometric traits, behavioral characteristics, and adaptation of local honeybees. Additionally, we discuss the threats posed by abiotic and biotic stressors and highlight the importance of conservation and sustainable management. The reviewed studies indicate that environmental factors significantly influence the behavioral characteristics and adaptation of local honeybees. Notably, the hygienic behavior of A. m. intermissa contributes to their resistance against diseases and the Varroa destructor mite. Further research in these areas is important for enhancing our understanding of honeybee health and population dynamics in Algeria, thereby informing strategies for sustainable beekeeping practices. Full article
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13 pages, 1435 KiB  
Article
Development of an Experimental Method Using a Portable Photosynthesis-Monitoring System to Measure Respiration Rates in Small-Sized Insects
by Bi-Yue Ding, Qin-Qin Xu, Yu-Jing Liu, Yu-Hong Zhong and Yan Zhou
Insects 2025, 16(6), 616; https://doi.org/10.3390/insects16060616 - 10 Jun 2025
Viewed by 253
Abstract
Respiration rates in insects are critical for survival and environmental adaptation, being influenced by developmental stages, environmental conditions, and the regulation of mitochondrial protein-coding genes. However, methods for field-based measurements in small-sized insects remain limited. In this study, we established a portable photosynthesis [...] Read more.
Respiration rates in insects are critical for survival and environmental adaptation, being influenced by developmental stages, environmental conditions, and the regulation of mitochondrial protein-coding genes. However, methods for field-based measurements in small-sized insects remain limited. In this study, we established a portable photosynthesis system to quantify respiration rates in five small-sized insects (body length < 8 mm): Acyrthosiphon pisum, Aphis citricidus, Tuta absoluta, Tribolium castaneum, and Bactrocera dorsalis. We tested its effectiveness across life stages and under diverse treatments, including light/dark cycles, insecticides, temperature shifts, starvation, mitochondrial inhibitors, and RNA interference. The system exhibited high sensitivity and reproducibility rates, revealing stage-specific respiration patterns. Various treatments, as well as expression changes in mitochondrial protein-coding genes, significantly affected respiration rates. This study validates the portable system as a reliable tool for insect respiration studies and highlights regulatory networks associated with respiratory plasticity. These findings enhance experimental methodologies and advance our understanding of insect adaptation to environmental stressors and pest control strategies. Full article
(This article belongs to the Special Issue Research on Insect Molecular Biology)
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14 pages, 645 KiB  
Review
Overview and Recent Advances in Bioassays to Evaluate the Potential of Entomopathogenic Fungi Against Ambrosia Beetles
by Jesús Enrique Castrejón-Antonio and Patricia Tamez-Guerra
Insects 2025, 16(6), 615; https://doi.org/10.3390/insects16060615 - 10 Jun 2025
Viewed by 333
Abstract
Ambrosia beetles, known for their symbiotic relationship with fungi cultivated within the tissues of host trees, have become significant pests, particularly when they serve as vectors for pathogenic fungi such as Raffaelea lauricola. Given the regulatory and environmental constraints for chemical application [...] Read more.
Ambrosia beetles, known for their symbiotic relationship with fungi cultivated within the tissues of host trees, have become significant pests, particularly when they serve as vectors for pathogenic fungi such as Raffaelea lauricola. Given the regulatory and environmental constraints for chemical application as a tool for their control, entomopathogenic fungi (EPF) represent a promising pest management alternative. This review presents an overview of bioassays assessing the pathogenicity and virulence of EPF against ambrosia beetles. Most studies have been performed in vivo (artificial diet) under laboratory conditions, focusing on exotic species and testing EPF genera such as Beauveria, Metarhizium, Isaria, and Purpureocillium. However, variations in inoculation methods, environmental conditions, and fungal formulations, have led to diverse results. In addition, the complex biology of these insects, particularly their dependence on symbiotic fungi, represents significant methodological challenges. Field trials (in situ bioassays) are still scarce, and there is a need to move toward standardized protocols and more objective experimental models that consider not only insects’ behavior but also ecological factors. Bridging this gap is essential for successfully implementing EPF-based strategies to assess ambrosia beetles’ biocontrol. Full article
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15 pages, 1181 KiB  
Article
Effects of Orally Delivered Double-Stranded RNA of Trehalose-6-Phosphate Synthase on the Population of Frankliniella occidentalis
by Tao Lin, Xiaoyu Chen, Ying Chen, Ting Chen, Xueyi Liang, Hui Wei and Guang Yang
Insects 2025, 16(6), 614; https://doi.org/10.3390/insects16060614 - 10 Jun 2025
Viewed by 325
Abstract
The invasive pest Frankliniella occidentalis (western flower thrip, WFT) severely impacts agricultural production. RNA interference (RNAi) has emerged as a viable alternative to chemical control methods. Trehalose-6-phosphate synthase (TPS) is an important enzyme for the synthesis of trehalose in insects. The TPS gene [...] Read more.
The invasive pest Frankliniella occidentalis (western flower thrip, WFT) severely impacts agricultural production. RNA interference (RNAi) has emerged as a viable alternative to chemical control methods. Trehalose-6-phosphate synthase (TPS) is an important enzyme for the synthesis of trehalose in insects. The TPS gene is a potential target for RNAi-based pest control; however, its efficacy against WFTs remains unclear. Feeding with the synthesized dsFoTPS to WFT significantly increased the mortalities of first- and second-instar nymphs and adults and significantly decreased the number of eggs laid by adults within 72 h; the expression of FoTPS was significantly down-regulated in 24, 48, and 72 h. Ingestion of WFTs on Escherichia coli expressing dsFoTPS led to a marked increase in the total pre-reproductive period; reductions in survival rate, adult longevity, oviposition days, fecundity, peak reproduction value, the intrinsic rate of increase, the finite rate of increase, and the net reproductive rate; and an extension of the mean generation time. TPS gene expression was significantly down-regulated on days 7 and 28. A population simulation of WFTs fed with E. coli expressing dsFoTPS indicated that the population suppression was reduced to 1/34 of the control in 100 d. Oral delivery of E. coli expressing dsFoTPS effectively inhibited the survival, fecundity, and population growth of WFTs, offering a novel approach and rationale for the prevention and control of WFTs. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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23 pages, 2291 KiB  
Article
Mating Behavior of Cyclocephala barrerai Martínez (Coleoptera: Melolonthidae)
by Abraham Sanchez-Cruz, Patricia Villa-Ayala and Alfredo Jiménez-Pérez
Insects 2025, 16(6), 613; https://doi.org/10.3390/insects16060613 - 10 Jun 2025
Viewed by 605
Abstract
Our study aimed to characterize mating behavior in virgin and once-mated males and females of Cyclocephala barrerai. We reared the specimens under laboratory conditions and recorded the age at which the organisms began their reproductive activity and the time they remained active. [...] Read more.
Our study aimed to characterize mating behavior in virgin and once-mated males and females of Cyclocephala barrerai. We reared the specimens under laboratory conditions and recorded the age at which the organisms began their reproductive activity and the time they remained active. We characterized behavioral acts during mating in two groups—virgin and once-mated organisms. Transitions between behaviors were analyzed using Markov chains and the generated ethograms. The duration of behaviors and the percentage of transitions were compared between the two groups. To characterize the mating behavior of C. barrerai, we adopted a framework commonly used in the literature, dividing mating behavior into three phases: premating, mating, and postmating. (A) Premating: Males search for females and mount and stimulate them, which the females resist through fighting behaviors. (B) Mating: The male mounts the female, which moves around and then stops; the male performs specific movements of the antennae and head and inserts his aedeagus into the female. (C) Postmating: Males exhibit guarding behavior over females. Although differences in pre- and postmating behaviors were observed between virgin and once-mated organisms, the duration of the acts did not show significant differences. These results provide key information on the reproductive behavior of C. barrerai, contributing to a better understanding of their biology and sexual interaction patterns. Full article
(This article belongs to the Special Issue Arthropod Reproductive Biology)
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20 pages, 4156 KiB  
Article
Reproductive Senescence in the Pollinator, Megachile rotundata
by Jacob B. Pithan, Brooke L. Kohler, Arun Rajamohan and Kendra J. Greenlee
Insects 2025, 16(6), 612; https://doi.org/10.3390/insects16060612 - 10 Jun 2025
Viewed by 571
Abstract
The disposable soma theory posits that organisms allocate limited resources between reproduction, maintenance, and growth, resulting in trade-offs, particularly as they age. In this study, we examined age-related reproductive senescence in Megachile rotundata, a solitary bee and important agricultural pollinator. We hypothesized [...] Read more.
The disposable soma theory posits that organisms allocate limited resources between reproduction, maintenance, and growth, resulting in trade-offs, particularly as they age. In this study, we examined age-related reproductive senescence in Megachile rotundata, a solitary bee and important agricultural pollinator. We hypothesized that, similarly to social bees, aging females would show declines in foraging behavior and reproductive fitness. Contrary to this hypothesis, we found no evidence of reproductive senescence in M. rotundata within the timeframe observed. Instead, older females increased their foraging rate, leading to larger provisions and offspring. We also observed that older bees exhibited improved foraging efficiency, likely due to learning and muscle physiology changes. Furthermore, ovarian development showed no decline with age, indicating that reproductive capacity remains stable throughout the observed timeframe. Our results challenge conventional assumptions about reproductive senescence in solitary bees and suggest that older M. rotundata may contribute to more efficient pollination, with implications for pollinator management. This study provides new insights into the aging process in solitary bees, emphasizing the need for further research into the mechanisms behind age-related behavioral and reproductive changes. Full article
(This article belongs to the Section Insect Physiology, Reproduction and Development)
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13 pages, 1070 KiB  
Article
Laboratory Test Indirectly Reveals the Unreliability of RNA-Dependent 16S rRNA Amplicon Sequences in Detecting the Gut Bacterial Diversity of Delia antiqua
by Miaomiao Li, Xin Cao, Linfeng Xu, Luyao Lin, Xiaoqing Wu, Susu Fan, Xinjian Zhang and Fangyuan Zhou
Insects 2025, 16(6), 611; https://doi.org/10.3390/insects16060611 - 10 Jun 2025
Viewed by 282
Abstract
In insect–microbe symbiosis, understanding the diversity of associated bacteria is crucial. DNA-dependent sequence methods are widely used to assess microbial diversity in insects, but they cannot distinguish between live and dead microbes. In contrast, RNA-dependent sequencing can identify alive bacterial communities, making them [...] Read more.
In insect–microbe symbiosis, understanding the diversity of associated bacteria is crucial. DNA-dependent sequence methods are widely used to assess microbial diversity in insects, but they cannot distinguish between live and dead microbes. In contrast, RNA-dependent sequencing can identify alive bacterial communities, making them more suitable for evaluating alive microbiota diversity. However, its practical reliability in insect–microbe symbiosis remains poorly validated. This study investigated larval gut bacteria diversity of Delia antiqua, a major pest of Liliaceae crops, by employing both DNA- and RNA-dependent 16S rRNA amplicon sequencing. The reliability of both sequencing methods was evaluated by comparing the effects of synthetic communities (SynComs, constructed according to DNA- or RNA-dependent sequencing) and bacterial communities from wild larvae on axenic larvae. Results revealed significant differences in bacterial community between DNA- and RNA-dependent sequence samples. Compared to bacterial communities from wild larvae, the SynCom constructed based on RNA-dependent sequencing exhibited inhibition effects on D. antiqua larvae survival and body weight, while DNA-dependent SynCom did not, suggesting that DNA-dependent methods were superior for assessing symbiotic microbiota in D. antiqua. This work will provide insights into microbial diversity detection in D. antiqua and offer a framework for other insect–microbe studies. Full article
(This article belongs to the Section Insect Behavior and Pathology)
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20 pages, 5993 KiB  
Article
High-Precision Stored-Grain Insect Pest Detection Method Based on PDA-YOLO
by Fuyan Sun, Zhizhong Guan, Zongwang Lyu and Shanshan Liu
Insects 2025, 16(6), 610; https://doi.org/10.3390/insects16060610 - 10 Jun 2025
Viewed by 366
Abstract
Effective stored-grain insect pest detection is crucial in grain storage management to prevent economic losses and ensure food security throughout production and supply chains. Existing detection methods suffer from issues such as high labor costs, environmental interference, high equipment costs, and inconsistent performance. [...] Read more.
Effective stored-grain insect pest detection is crucial in grain storage management to prevent economic losses and ensure food security throughout production and supply chains. Existing detection methods suffer from issues such as high labor costs, environmental interference, high equipment costs, and inconsistent performance. To address these limitations, we proposed PDA-YOLO, an improved stored-grain insect pest detection algorithm based on YOLO11n which integrates three key modules: PoolFormer_C3k2 (PF_C3k2) for efficient local feature extraction, Attention-based Intra-Scale Feature Interaction (AIFI) for enhanced global context awareness, and Dynamic Multi-scale Aware Edge (DMAE) for precise boundary detection of small targets. Trained and tested on 6200 images covering five common stored-grain insect pests (Lesser Grain Borer, Red Flour Beetle, Indian Meal Moth, Maize Weevil, and Angoumois Grain Moth), PDA-YOLO achieved an mAP@0.5 of 96.6%, mAP@0.5:0.95 of 60.4%, and F1 score of 93.5%, with a computational cost of only 6.9 G and mean detection time of 9.9 ms per image. These results demonstrate the advantages over mainstream detection algorithms, balancing accuracy, computational efficiency, and real-time performance. PDA-YOLO provides a reference for pest detection in intelligent grain storage management. Full article
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