Insects

14 pages, 2210 KiB

Open AccessArticle

Nesting Preferences of Osmia orientalis (Hymenoptera: Megachilidae) in the Field and Its Potential as a Strawberry Pollinator in Greenhouses

by Ikuo Kandori, Yudai Ogata and Tomoyuki Yokoi

Insects 2025, 16(5), 473; https://doi.org/10.3390/insects16050473 - 29 Apr 2025

Abstract

The western honeybee, Apis mellifera, is used worldwide as a pollinator of crops such as strawberries; however, it is an introduced species in Japan. The mason bee, Osmia orientalis Benoist (Hymenoptera: Megachilidae), is native to Japan, where it nests in empty snail [...] Read more.

The western honeybee, Apis mellifera, is used worldwide as a pollinator of crops such as strawberries; however, it is an introduced species in Japan. The mason bee, Osmia orientalis Benoist (Hymenoptera: Megachilidae), is native to Japan, where it nests in empty snail shells and has potential as a crop pollinator. We conducted three experiments to collect information on the nesting habits and potential agricultural use of this species as a pollinator of greenhouse-grown strawberries. Our first experiment investigated the bees’ nesting preferences in the field by placing the empty shells of four snail species, Euhadra amaliae, Satsuma japonica, Sinotaia quadrata histrica, and Helix lucorum, in six different environments. The nesting rate was significantly higher in medium-sized, empty E. amaliae shells. Regarding the surrounding environment, O. orientalis preferred tall and short grasslands to bare ground and forest interiors. Our second experiment investigated per-visit strawberry flower pollination efficiency. The results indicated that the efficiency of O. orientalis was equal to or greater than that of A. mellifera. In our third experiment, as a replacement for empty snail shells, which are scarce natural sources, four types of plastic artificial shells were created and placed inside a greenhouse together with E. amaliae shells. The nesting rates in three types of artificial shells were nearly identical to those in E. amaliae shells, implying that these artificial shells may be effective nesting materials. Although many questions remain before practical application, our results indicate the potential for using O. orientalis as a pollinator of greenhouse-grown strawberries. Full article

(This article belongs to the Collection Insects on Pollination Ecology)

18 pages, 1518 KiB

Open AccessArticle

Adding Fruit Fermentation Liquid Improves the Efficiency of the Black Soldier Fly in Converting Chicken Manure and Reshapes the Structure of Its Intestinal Microbial Community

by Lifei Chen, Guiying Wang, Hanhan Song, Qi Yang, Jiani Fu, Jiale Liu, Haoyang Sun, Yuxi Wang, Qile Tian, Yuting Sun, Lei Sun, Hao Xin, Zuyin Xiao, Guoliang Wang, Zixuan Zhang, Yinling Zhao, Hongyan Yang and Lusheng Li

Insects 2025, 16(5), 472; https://doi.org/10.3390/insects16050472 - 29 Apr 2025

Abstract

This study evaluated how fruit fermentation liquid (FFL) enhances the conversion of chicken manure by black soldier fly larvae (BSFL) and modulates their gut microbiota. Three groups were tested: control (A: 300 g manure + 50 g water), low-dose FFL (B: 300 g [...] Read more.

This study evaluated how fruit fermentation liquid (FFL) enhances the conversion of chicken manure by black soldier fly larvae (BSFL) and modulates their gut microbiota. Three groups were tested: control (A: 300 g manure + 50 g water), low-dose FFL (B: 300 g manure + 25 g FFL + 25 g water), and high-dose FFL (C: 300 g manure + 50 g FFL). The results show that the dry matter conversion rate significantly increased by 9.5% (p < 0.05), while the feed-to-larvae ratio was reduced by 1.02 (p < 0.01) in group C. NH₃ emissions in group C decreased by 24.48 mg·kg⁻¹·DM (dry matter substrate) day⁻¹ (24.48 mg per kilogram of dry matter substrate per day) (p < 0.01), with suppressed H₂S release. Gut microbiota analysis revealed that FFL reduced the abundance of Proteobacteria (6.07% decrease in group C) while enriching Actinobacteriota (4.68% increase) and beneficial genera (Corynebacterium, Gallicola). Substrate microbial diversity in group C improved, with Proteobacteria and Firmicutes increasing by 11.07% and 4.83%, respectively, and pathogenic Sphingobacteriaceae declining by 21.16% by day 7. FFL likely introduced organic acids and nutrients, enhancing larval digestion and nutrient absorption while inhibiting the production of harmful gases. These findings demonstrate that FFL optimizes BSFL-driven waste conversion efficiency through modulation of the microbiota, offering a sustainable strategy for organic waste management and contributing to circular agricultural systems. Full article

(This article belongs to the Section Role of Insects in Human Society)

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9 pages, 1796 KiB

Open AccessCommunication

Hydrogen Stable Isotopes Indicate Reverse Migration of Fall Armyworm in North America

by Eduardo S. Calixto and Silvana V. Paula-Moraes

Insects 2025, 16(5), 471; https://doi.org/10.3390/insects16050471 - 29 Apr 2025

Abstract

Fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae), is a major pest in the U.S. and has spread globally, causing severe agricultural losses in different countries. Due to its high mobility and potential for long-distance dispersal, understanding FAW migration is [...] Read more.

Fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae), is a major pest in the U.S. and has spread globally, causing severe agricultural losses in different countries. Due to its high mobility and potential for long-distance dispersal, understanding FAW migration is a key tool for forecasting outbreaks and implementing timely management measures. Recent studies using stable hydrogen isotopes indicated reverse (southward) migration of Helicoverpa zea Boddie (Lepidoptera: Noctuidae). Here, we tested the reverse migration hypothesis for FAW in North America. Estimation of the hydrogen isotopic ratio on 324 samples collected in Florida, an intermixing zone at the edge of the continental U.S., indicated evidence of reverse migration in samples of FAW moths. They showed a high probability of origin from the U.S. Corn Belt, with a greater probability of origin in Nebraska, South Dakota, Minnesota, Kansas and Wisconsin. This southward movement provides new insights into the risk of spreading pesticide resistance alleles in this species to southern regions and contributes to the improvement of integrated pest management and insect resistance management programs. Full article

(This article belongs to the Special Issue Corn Insect Pests: From Biology to Control Technology)

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16 pages, 5233 KiB

Open AccessArticle

Effects of Colony Breeding System and Nest Architecture on Soil Microbiome and Fertility in the Fungus-Growing Termite Macrotermes barneyi Light

by Jiachang Zhou, Wenquan Qin, Yang Zeng, Xin Huang, Jing Yuan, Yuting Yin, Paike Xu, Xiaohong Fan, Runfeng Zhang, Ganghua Li and Yinqi Zhang

Insects 2025, 16(5), 470; https://doi.org/10.3390/insects16050470 - 29 Apr 2025

Abstract

Macrotermes barneyi is a typical fungus-growing termite that forms both monogynous (single queen) and polygynous (multiple queen) colonies in nature. This species influences the local soil fertility in part by redistributing nutrients across the landscape in its habitats. However, how the colony structure [...] Read more.

Macrotermes barneyi is a typical fungus-growing termite that forms both monogynous (single queen) and polygynous (multiple queen) colonies in nature. This species influences the local soil fertility in part by redistributing nutrients across the landscape in its habitats. However, how the colony structure of M. barneyi affects nutrient cycling and microbial communities within the nest is not well understood. In this study, we compared the physicochemical properties and microbial communities across nest parts between monogynous and polygynous colonies of M. barneyi. Our results showed that the fungus garden is the most nutrient-rich part of the nest, with higher soil moisture, organic matter, ammonium nitrogen, nitrate nitrogen, available sulfur, available potassium, available silicon, and available boron than other nest parts. Notably, the fungus garden in monogynous colonies had higher nitrate nitrogen, available sulfur, and available silicon than those in the polygynous colonies. The microbial α-diversity in the fungus garden was lower than that in other parts of the nest. β-diversity analysis revealed a clear separation of microbial communities between monogynous and polygynous colonies across nest parts. Furthermore, the relative abundance of functional genes associated with “cell cycle control, cell division, and chromosome partitioning” was higher in the fungus garden of polygynous colonies compared to monogynous colonies. Our results suggest that the fungus garden plays a crucial role in maintaining colony stability in M. barneyi colonies. The rapid depletion of nutrients in the fungus garden to sustain the larger population in polygynous colonies likely influences microbial community dynamics and nutrient cycling. Full article

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

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16 pages, 7129 KiB

Open AccessArticle

by Luyu Hou, Jinxin Wu, Die Liu, Haoran Xu, Hongbo Yao, Yiwen Liang, Qingyou Xia, Ping Lin and Guanwang Shen

Insects 2025, 16(5), 469; https://doi.org/10.3390/insects16050469 - 29 Apr 2025

Abstract

Estrogen-related receptors (ERRs) are important transcription factors within the nuclear receptor family that regulate cellular energy storage and consumption by binding to estrogen-related receptor response elements (ERREs) on gene promoters. While ERRs’ role in vertebrates is well-studied, their molecular mechanisms in insect metabolism [...] Read more.

Estrogen-related receptors (ERRs) are important transcription factors within the nuclear receptor family that regulate cellular energy storage and consumption by binding to estrogen-related receptor response elements (ERREs) on gene promoters. While ERRs’ role in vertebrates is well-studied, their molecular mechanisms in insect metabolism and development remain unclear. This study systematically summarizes the functions of ERRs in insects, focusing on silkworms by analyzing gene functions and comparing databases. ERRE-like elements were identified in the 2000 bp upstream promoter regions of 69 metabolism-related silkworm genes. Furthermore, electrophoretic mobility shift assays (EMSAs) revealed that ERREs within the promoters of 15 genes related to sugar, fat, and protein metabolism specifically bind to ERR. Notably, an ERRE in the promoter of the trehalose transporter 1 gene (BmTret1), crucial for trehalose homeostasis in insect hemolymph, exhibited significantly enhanced activity in ERR-overexpressing cells. These findings suggest that ERR is a potential regulatory factor in silkworm metabolism and refine its metabolic regulatory network. This study highlights the broader and more critical role of ERR in insects than that previously recognized, contributing to a deeper understanding of insect metabolism and its potential applications in related fields. Full article

(This article belongs to the Special Issue Genomics and Molecular Biology in Silkworm)

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12 pages, 1702 KiB

Open AccessArticle

Use of Sugar Dispensers at Lower Density Can Decrease Mealybug (Hemiptera: Pseudococcidae) Infestation in Vineyards by Disrupting Ants

by Giovanni Burgio, Serena Magagnoli, Luca Casoli, Marco Profeta, Donato Antonio Grasso, Enrico Schifani, Daniele Giannetti and Martina Parrilli

Insects 2025, 16(5), 468; https://doi.org/10.3390/insects16050468 - 29 Apr 2025

Abstract

Vineyard mealybugs (Hemiptera: Pseudococcidae) are economic pests in vineyards, demanding integrated control strategies. Several ant species can facilitate mealybug infestation by protecting them from natural enemies in a mutualistic relationship known as trophobiosis. In the frame of an ant management system, the provision [...] Read more.

Vineyard mealybugs (Hemiptera: Pseudococcidae) are economic pests in vineyards, demanding integrated control strategies. Several ant species can facilitate mealybug infestation by protecting them from natural enemies in a mutualistic relationship known as trophobiosis. In the frame of an ant management system, the provision of sugary liquid has proved worldwide to improve mealybug control. In the present study, a field trial was carried out within an important vineyard cultivation area of northern Italy with the aim of testing a lower density (80/ha) of sugar dispenser to facilitate the practicality of this method. The sugar dispensers tested, along with predators and parasitoid release, were effective in reducing mealybug infestations by 22% and resulted in a double increase in larval density of the predator Cryptolaemus mountrouzieri Mulsant. Mealybug parasitism was in general high, but it was not improved by sugar dispensers at this density. Our field validation confirms the importance of ants in mealybug infestation dynamics, and the benefits of ant management in the context of integrated strategies against mealybugs. Full article

(This article belongs to the Special Issue Advances in Research on Parasitoids for Biological Control of Agricultural Pests)

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17 pages, 4143 KiB

Open AccessArticle

Repellent Activity of DEET and Biont-Based Mosquito Repellents in the Chinese Market Against the Asian Long-Horned Tick, Haemaphysalis longicornis

by Weiqing Zheng, Yuyang Zhang, Jingzhi Huang, Qinglu Wu, Jintong Fu, Yongwei Wen, Siyu Fang, Xiaoyan Yang and Qianfeng Xia

Insects 2025, 16(5), 467; https://doi.org/10.3390/insects16050467 - 29 Apr 2025

Abstract

To investigate the repellent efficacy of commercially available mosquito repellents in China against Haemaphysalis longicornis, four representative DEET-based repellents and biont-derived repellents were selected. This study utilized a modified circular filter paper method repellent testing device to establish an evaluation system for [...] Read more.

To investigate the repellent efficacy of commercially available mosquito repellents in China against Haemaphysalis longicornis, four representative DEET-based repellents and biont-derived repellents were selected. This study utilized a modified circular filter paper method repellent testing device to establish an evaluation system for assessing the repellent effects of each product against three developmental stages of H. longicornis: larvae, nymphs, and adults. In our study, for DEET-based repellents, Johnson demonstrated the highest repellency against larvae within 1 h, with an average repellency rate exceeding 80.14%. Yamei and Johnson exhibited repellency rates more than 91.11% for nymphs within 1 h, surpassing the other two DEET products. Repellency rates of Longliqi and Xiaohuanxiong fluctuated between 80.95% and 100% at different time points. Yamei, Longliqi, and Johnson achieved 100% repellency to adults within 1 h, while Xiaohuanxiong showed slightly lower efficacy. The four biont-derived repellents showed significant variations in efficacy: larval-stage repellency ranged from 14.29% to 88.89%, nymphal-stage repellency from 57.89% to 100%, and adult-stage repellency from 50% to 79.49%. CaliforniaBaby exhibited the highest efficacy, comparable or superior to DEET-based products, whereas Longhu demonstrated the weakest repellency and poor persistence. We further conducted a persistence test for CaliforniaBaby and found that it maintained >75% repellency against H. longicornis for 6 h. This study provides scientific evidence for selecting tick repellents in practice, offers guidance for purchasing commercial biont-derived tick repellents, and serves as a reference for developing safer, more effective tick repellents. Full article

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

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20 pages, 3055 KiB

Open AccessArticle

Mealworm Frass as a Novel Insect Food-Based Attractant: The Case of Bactrocera oleae (Diptera: Tephritidae)

by Ioannis E. Koufakis, Argyro P. Kalaitzaki, George D. Broufas, Antonios E. Tsagkarakis and Maria L. Pappas

Insects 2025, 16(5), 466; https://doi.org/10.3390/insects16050466 - 28 Apr 2025

Abstract

The management of Bactrocera oleae (Rossi, 1790) has relied on chemical insecticides, applied as bait or cover sprays. However, concerns over insecticide resistance and environmental impact have driven the search for more effective and eco-friendly alternatives, such as mass trapping. The aim of [...] Read more.

The management of Bactrocera oleae (Rossi, 1790) has relied on chemical insecticides, applied as bait or cover sprays. However, concerns over insecticide resistance and environmental impact have driven the search for more effective and eco-friendly alternatives, such as mass trapping. The aim of the study was to assess a novel food-based attractant, derived from Tenebrio molitor Linnaeus, 1758 excreta “Frass”, for its attractiveness to B. oleae adults compared to widely used commercial food-based attractants. Over a four-year period, five field trials were conducted in two organic olive groves in Crete, Greece, using a randomized complete block design with five or six replicate blocks. Results showed that frass-based attractants captured significantly higher number of B. oleae adults than the other tested attractants. Additionally, trap–attractant combinations were assessed to determine the most efficient mass-trapping system. Frass-based attractant deployed in Anel or container traps demonstrated significantly higher attractiveness than all commercial traps and lures tested. The significant advantages of mealworm frass as an attractant highlight its potential to enhance the monitoring and suppression of B. oleae in olive orchards. Its consistent performance, sustainability, and environmental safety make it a promising tool in integrated pest management strategies. Full article

(This article belongs to the Special Issue Advances in Insect Pest Management: Innovative Approaches to Enhance Plant Protection)

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10 pages, 668 KiB

Open AccessArticle

Impact of Sulfoxaflor on Brown Marmorated Stink Bug: Developmental and Reproductive Effects

by Ren Li, Zehua Wang, Fan Yang, Tao Su, Guanghang Qiao and Shanning Wang

Insects 2025, 16(5), 465; https://doi.org/10.3390/insects16050465 - 28 Apr 2025

Abstract

The brown marmorated stink bug, Halyomorpha halys, has become a severe threat to agriculture worldwide with continuous invasion and spread. Sulfoxaflor is the pioneering sulfoximine insecticide and has been widely employed for managing sap-feeding insect pests across diverse crops. However, the sublethal [...] Read more.

The brown marmorated stink bug, Halyomorpha halys, has become a severe threat to agriculture worldwide with continuous invasion and spread. Sulfoxaflor is the pioneering sulfoximine insecticide and has been widely employed for managing sap-feeding insect pests across diverse crops. However, the sublethal effects of sulfoxaflor on the growth and reproduction of H. halys remain unexplored. This study employed age-stage life tables and physiological parameters to evaluate the sublethal effects of sulfoxaflor on H. halys. The bioassay results indicated that the LC₂₀ and LC₅₀ values of sulfoxaflor against second-instar nymphs of H. halys were 7.75 and 20.97 mg/L, respectively. Treatment with the LC₂₀ concentration of sulfoxaflor reduced the lifespan of female adults by 11.74 days. Importantly, the oviposition period of females was shortened by 9.47 days, and the fecundity was decreased by 1.4-fold. Additionally, the activities of cytochrome P450 (P450s) and glutathione S-transferase (GSTs) enzymes in H. halys were enhanced 1.40 and 1.54 times after treatment with sublethal concentrations of sulfoxaflor. These findings demonstrate that sublethal concentrations of sulfoxaflor significantly inhibit the population development of H. halys. Moreover, the detoxification enzymes P450s and GSTs may be associated with the potential resistance to sulfoxaflor in H. halys. This information provides valuable insights into the application of sulfoxaflor in the management of this pest. Full article

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

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17 pages, 4181 KiB

Open AccessArticle

“Hostbusters”: The Bacterial Endosymbiont Wolbachia of the Parasitoid Wasp Habrobracon hebetor Improves Its Ability to Parasitize Lepidopteran Hosts

by Alsu M. Utkuzova, Ekaterina A. Chertkova, Natalia A. Kryukova, Julia M. Malysh and Yuri S. Tokarev

Insects 2025, 16(5), 464; https://doi.org/10.3390/insects16050464 - 28 Apr 2025

Abstract

Habrobracon hebetor is a globally acknowledged larval ectoparasitoid that is widely used to control lepidopteran pests. Wolbachia is a natural endosymbiont that regulates various aspects of the insect host biology. The ability of H. hebetor to paralyze and develop on lepidopteran larvae from [...] Read more.

Habrobracon hebetor is a globally acknowledged larval ectoparasitoid that is widely used to control lepidopteran pests. Wolbachia is a natural endosymbiont that regulates various aspects of the insect host biology. The ability of H. hebetor to paralyze and develop on lepidopteran larvae from five families was tested under laboratory conditions. Two lines of the wasp were used, “W+” containing a naturally occurring Wolbachia from the supergroup B, and “W−”, with the endosymbiont eradicated by antibiotic treatment, followed by propagation of 20 subsequent generations. The proportions of larvae in which host paralysis, as well as parasitoid oviposition, larval, pupal, and adult development were observed, were usually higher in W+ compared to W−. In Loxostege sticticalis, differences in these indices were not statistically significant. In Galleria mellonella, Mamestra brassicae, and Ostrinia nubilalis, some of the parasitism indices were significantly higher in W+ than in W−. In Bombyx mori and Plutella xylostella, H. hebetor could not complete its life cycle, but parasitism levels at the initial steps (from paralysis symptoms to the presence of larvae/pupae of the parasitoid) were 2–5 times lower in W− compared to W+ (p < 0.01). It can be suggested that the presence of Wolbachia is advantageous for H. hebetor, as it increases the success of parasitism in a broad range of lepidopteran hosts. Full article

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

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16 pages, 1482 KiB

Open AccessReview

Exploring the Role of mRNA Methylation in Insect Biology and Resistance

by Jiayang Zhang, Luobin Lin, Botian Huang, Huoxi Liu, Huaqin Li and Wenmei Wu

Insects 2025, 16(5), 463; https://doi.org/10.3390/insects16050463 - 28 Apr 2025

Abstract

RNA methylation, characterized by modifications such as N⁶-methyladenosine, 5-methylcytosine, and N¹-methyladenosine plays a crucial role in post-transcriptional gene regulation across diverse biological systems. While research on RNA methylation has predominantly focused on mammals, particularly its roles in epigenetic regulation [...] Read more.

RNA methylation, characterized by modifications such as N⁶-methyladenosine, 5-methylcytosine, and N¹-methyladenosine plays a crucial role in post-transcriptional gene regulation across diverse biological systems. While research on RNA methylation has predominantly focused on mammals, particularly its roles in epigenetic regulation and cancer biology, recent studies in insects have begun to explore their extensive functions in insect physiology. This review examines the mechanisms by which RNA methylation regulates growth, development, reproduction, environmental adaptation, and immune response in insects, providing insights into the biological characteristics of these organisms without prematurely speculating on pest control strategies. It aims to offer valuable insights into the role of RNA methylation in insect biology and resistance. Full article

(This article belongs to the Topic Advances in Integrated Pest Management: New Tools and Tactics for Pest Control)

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11 pages, 1168 KiB

Open AccessArticle

Elevated Plasmodium Sporozoite Infection Rates in Primary and Secondary Malaria Vectors in Anopheles stephensi-Infested Areas of Ethiopia

by Dawit Hawaria, Timotwos Amanuel, Abraham Anbesie, Daibin Zhong, Solomon Kibret, Ming-Chieh Lee, Guofa Zhou, Chloe Wang, Jiale Chen, Tafesse Matewos, Amanuel Ejeso, Chirotaw Ayele, Temesgen Yosef, Delenesaw Yewhalaw and Guiyun Yan

Insects 2025, 16(5), 462; https://doi.org/10.3390/insects16050462 - 27 Apr 2025

Abstract

Assessing bloodmeal sources and sporozoite infection rates in mosquito vectors is essential for understanding their role in malaria transmission. This study investigated these factors in Hawassa, Southern Ethiopia—an area recently invaded by Anopheles stephensi—through adult mosquito collections conducted between January and April [...] Read more.

Assessing bloodmeal sources and sporozoite infection rates in mosquito vectors is essential for understanding their role in malaria transmission. This study investigated these factors in Hawassa, Southern Ethiopia—an area recently invaded by Anopheles stephensi—through adult mosquito collections conducted between January and April 2023 using BG-Pro traps, CDC Light Traps, and Prokopack Aspirators. A total of 738 female Anopheles mosquitoes were collected, including An. arabiensis (72.9%), An. pharoensis (13.4%), An. stephensi (7.5%), and An. coustani (6.2%). Human Blood Index (HBI) values were 23.3% for An. arabiensis, 43.8% for An. pharoensis, 8.3% for An. stephensi, and 25.0% for An. coustani. Plasmodium infection was detected in 8% of An. arabiensis and 4.7% of An. pharoensis, while An. stephensi and An. coustani were uninfected. The findings highlight the presence of multiple competent malaria vectors, with significant infection rates observed in both primary and secondary species, underscoring the need to include secondary vectors in control and surveillance programs. The detection of An. stephensi alongside native vectors adds complexity to malaria control efforts, reinforcing the importance of continuous monitoring to understand the changing dynamics of vector populations and their roles in transmission. Full article

(This article belongs to the Special Issue Insecticide Resistance in Mosquitoes)

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23 pages, 14601 KiB

Open AccessArticle

Deciphering the Olfactory Mechanisms of Sitotroga cerealella Olivier (Lepidoptera: Gelechiidae): Insights from Transcriptome Analysis and Molecular Docking

by Hui Li, Sheng Qiao, Xiwen Hong and Yangyang Wei

Insects 2025, 16(5), 461; https://doi.org/10.3390/insects16050461 - 27 Apr 2025

Abstract

Olfaction is crucial for insect activities such as host seeking, foraging, oviposition, and predator avoidance. While olfactory proteins have been identified across several insect species, their specific functions are largely enigmatic. In this study, we investigated the olfactory proteins of the Angoumois grain [...] Read more.

Olfaction is crucial for insect activities such as host seeking, foraging, oviposition, and predator avoidance. While olfactory proteins have been identified across several insect species, their specific functions are largely enigmatic. In this study, we investigated the olfactory proteins of the Angoumois grain moth, Sitotroga cerealella Olivier. A total of 165 presumptive olfactory genes were identified in the antennal transcriptome of S. cerealella, encompassing 33 odorant-binding proteins (OBPs), 10 chemosensory proteins (CSPs), 58 odorant receptors (ORs), 41 ionotropic receptors (IRs), 21 gustatory receptors (GRs), and 2 sensory neuron membrane proteins (SNMPs). BLASTX and a phylogenetic analysis showed a high similarity of these genes to the orthologs in other model insects. A qRT-PCR analysis demonstrated that ScerOBP15 and ScerOBP23 are specifically and highly expressed in antennae, exhibiting male-biased expression patterns. Moreover, molecular docking revealed their strong binding affinity to the wheat volatiles n-heptadecane and geranyl acetone. Also, the potential active sites within ScerOBP15 and ScerOBP23 that engage with these volatiles have been identified, implying a possible role in host localization. Our findings shed light on the mechanisms underlying the behavioral responses of S. cerealella to wheat odors, enhance our comprehension of their olfactory processes, and pave the way for the development of highly specific and sustainable pest management strategies. Full article

(This article belongs to the Special Issue Research on Insect Molecular Biology)

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10 pages, 1013 KiB

Open AccessArticle

miRNA Expression Response of Aedes aegypti (Linnaeus 1762) (Diptera: Culicidae) to Imidacloprid Exposure

by Gerardo Trujillo-Rodríguez, Mariana Lizbeth Jiménez-Martínez, Elda Flores-Contreras, Everardo González Gonzalez, María de Lourdes Ramírez Ahuja, Idalia Garza Veloz, Adriana E. Flores Suarez, Fabian Correa Morales, Felipe Dzul Manzanilla, Iram P. Rodriguez Sanchez and Margarita L. Martínez Fierro

Insects 2025, 16(5), 460; https://doi.org/10.3390/insects16050460 - 27 Apr 2025

Abstract

Aedes aegypti is a major vector of arboviruses, including dengue, Zika, chikungunya, yellow fever, and Mayaro. The extensive use of insecticides has led to resistance, complicating vector control efforts. MicroRNAs (miRNAs) are post-transcriptional regulators involved in detoxification and stress adaptation; however, their role [...] Read more.

Aedes aegypti is a major vector of arboviruses, including dengue, Zika, chikungunya, yellow fever, and Mayaro. The extensive use of insecticides has led to resistance, complicating vector control efforts. MicroRNAs (miRNAs) are post-transcriptional regulators involved in detoxification and stress adaptation; however, their role in the insecticide response of Ae. aegypti remains unclear. This study analyzed miRNA expression in Ae. aegypti following imidacloprid exposure, comparing a field strain, Martinez de la Torre from Mexico (MT), and a susceptible reference strain, New Orleans (NO). Small RNA sequencing identified 96 miRNAs, with miR-1, miR-281-5p, miR-100, and miR-184 being consistently expressed across all conditions. In contrast, let-7, miR-124, and miR-13-3p were exclusively detected in wild mosquitoes exposed to imidacloprid, while miR-14 and miR-275-3p showed condition-specific expression. Distinct miRNA expression patterns were observed between the field and susceptible strains, with specific miRNAs showing condition-dependent expression. These findings suggest that certain miRNAs may serve as potential biomarkers for resistance monitoring, contributing to a better understanding of insecticide response mechanisms and informing novel vector control strategies. Full article

(This article belongs to the Special Issue Biology, Ecology and Management of Mosquitoes Affecting Humans and Animals)

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12 pages, 1043 KiB

Open AccessArticle

Field-Based Evaluation of Insecticide Effectiveness on Megalurothrips usitatus in Guangdong, China: Implications for Pest Control Strategies

by Zhengke Peng, Mengni Li, Chaosong Guo, Huixin Zheng, Mingyue Wu, Fei Yin, Yong Xiao, Huanhuan Wang, Xiangyi Kong, Myron P. Zalucki, Wen Xie and Zhenyu Li

Insects 2025, 16(5), 459; https://doi.org/10.3390/insects16050459 - 27 Apr 2025

Abstract

In southern China, cowpea production is severely threatened by Megalurothrips usitatus due to its fast-evolving resistance to insecticides. The toxicity monitoring of commonly used insecticides against field populations provides key information for the resistance management of pests. In this study, field populations of [...] Read more.

In southern China, cowpea production is severely threatened by Megalurothrips usitatus due to its fast-evolving resistance to insecticides. The toxicity monitoring of commonly used insecticides against field populations provides key information for the resistance management of pests. In this study, field populations of Megalurothrips usitatus were collected from three locations (QY, YF, MM) in Guangdong, and the sensitivity of these populations against insecticides was determined by using a thrips insecticides bioassay system (TIBS) method. The bioassay results indicated there were sensitivity variances to insecticides between these three field populations. Among these 10 insecticides, spinetoram and spinosad both showed high toxicity against all three field populations. In addition, broflanilide for QY, emamectin benzoate for YF, and emamectin benzoate and cyantraniliprole for MM were suggested as alternate insecticides to alleviate selective pressure from insecticides on field populations. In field experiments, the corrected control efficacy of cyantraniliprole and spinetoram against M. usitatus was over 75% at 7 dpa, which proved to be ideal insecticides for field application. These field-based results provide guidance for chemical control against thrips and can be valuable in proposing appropriate strategies for thrips resistance management. Full article

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

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20 pages, 5859 KiB

Open AccessArticle

A Complex of Lance Flies (Diptera: Lonchaeidae) Infesting Figs in Veracruz, Mexico, with the Description of a New Species

by Rodrigo Lasa, Laura Navarro-de-la-Fuente, Iain MacGowan and Trevor Williams

Insects 2025, 16(5), 458; https://doi.org/10.3390/insects16050458 - 27 Apr 2025

Abstract

The black fig fly, Silba adipata, and a complex of Neosilba species have emerged as major fig pests in Veracruz, Mexico. To assess infestation patterns and species composition, we sampled figs during one production cycle (March–October 2024) in two plantations. A total [...] Read more.

The black fig fly, Silba adipata, and a complex of Neosilba species have emerged as major fig pests in Veracruz, Mexico. To assess infestation patterns and species composition, we sampled figs during one production cycle (March–October 2024) in two plantations. A total of 1647 S. adipata (821 females, 826 males) and 1250 Neosilba spp. (628 females, 622 males) emerged from samples. One species, Neosilba recurva, is described as new based on the characteristics of the male genitalia and COI sequencing. Neosilba spp. outnumbered S. adipata in the preharvest period, after which S. adipata became dominant. S. adipata emerged ~14 days earlier than Neosilba spp. Infestation by S. adipata caused uniform fig reddening, while Neosilba spp. produced patchy redness near larval exit holes. Approximately 65% of figs were lost to lonchaeid infestation preharvest. Based on male genitalia, we identified Neosilba batesi and N. recurva sp. nov. (that together comprised 64% of samples), as well as Neosilba sp.1 (26%) and N. glaberrima (10%), but COI sequences revealed greater diversity. Neosilba batesi formed a clade that did not match a Floridan sequence. Neosilba glaberrima clustered near N. pendula from Brazil, but another sequence diverged, suggesting the presence of an additional, undescribed species, Neosilba sp.2? Neosilba recurva and Neosilba sp.1, together with the newly described N. flavitarsis from Veracruz, formed distinct genetic branches, supporting their specific status. Full article

(This article belongs to the Special Issue Fly Biology, Ecology, Behavior and Management—2nd Edition)

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24 pages, 2189 KiB

Open AccessReview

Medical Potential of Insect Symbionts

by Fanglei Fan, Zhengyan Wang, Qiong Luo, Zhiyuan Liu, Yu Xiao and Yonglin Ren

Insects 2025, 16(5), 457; https://doi.org/10.3390/insects16050457 - 26 Apr 2025

Abstract

Insect symbionts and their metabolites are complex and diverse and are gradually becoming an important source of new medical materials. Some culturable symbionts from insects produce a variety of active compounds with medical potential. Among them, fatty acids, antibacterial peptides, polyene macrolides, alkaloids, [...] Read more.

Insect symbionts and their metabolites are complex and diverse and are gradually becoming an important source of new medical materials. Some culturable symbionts from insects produce a variety of active compounds with medical potential. Among them, fatty acids, antibacterial peptides, polyene macrolides, alkaloids, and roseoflavin can inhibit the growth of human pathogenic bacteria and fungi; lipases, yeast killer toxins, reactive oxygen species, pyridines, polyethers, macrotetrolide nactins, and macrolides can kill human parasites; and peptides and polyketides can inhibit human tumors. However, due to difficulty in the culture of symbionts in vitro, difficulty in targeting bacteria to specific sites in the human body, the limited capability of symbionts to produce active metabolites in vitro, inconsistent clinical research results, adverse reactions on humans, and the development of antibiotic resistance, the application of insect symbionts and their metabolites in the medical field remains in its infancy. This paper summarizes the medical potential of insect symbionts and their metabolites and analyzes the status quo and existing problems with their medical application. Possible solutions to these problems are also proposed, with the aim of hastening the utilization of insect symbionts and their metabolites in the medical field. Full article

(This article belongs to the Section Role of Insects in Human Society)

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33 pages, 8331 KiB

Open AccessArticle

Contribution to the African Ladybird Genus Epipleuria Fürsch (Coccinellidae: Coccidulini) with Description of a New Genus

by Tomasz Czerwiński and Karol Szawaryn

Insects 2025, 16(5), 456; https://doi.org/10.3390/insects16050456 - 25 Apr 2025

Abstract

The endemic African genus Epipleuria Fürsch is re-described, diagnosed and confronted with African species of the closely related genus Rhyzobius Stephens. The validity of the genus Epipleuria is confirmed. Two new species, Epipleuria capensis sp. nov. and Epipleuria tsitsikamma sp. nov., from [...] Read more.

The endemic African genus Epipleuria Fürsch is re-described, diagnosed and confronted with African species of the closely related genus Rhyzobius Stephens. The validity of the genus Epipleuria is confirmed. Two new species, Epipleuria capensis sp. nov. and Epipleuria tsitsikamma sp. nov., from the Republic of South Africa are described. Additionally, the male genitalia of Epipleuria natalensis Fürsch, 2001, are described and illustrated for the first time. Epipleuria endroedyi Fürsch, 2001; Epipleuria mahnerti Fürsch, 2001; and Rhyzobius stillatus Fürsch, 1992, are transferred to the newly established genus Pseudoepipleuria gen. nov. Full article

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

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13 pages, 1802 KiB

Open AccessArticle

Flupyradifurone Exhibits Greater Toxicity to the Asian Bumblebee Bombus lantschouensis Compared to the European Bumblebee Bombus terrestris

by Chunting Jie, Hong Zhang, Ziyu Zhou, Zhengying Miao, Bo Han, Baodi Guo, Yi Guo, Xiao Hu, Shahid Iqbal, Bingshuai Wei, Jiaxing Huang, Pingli Dai and Jiandong An

Insects 2025, 16(5), 455; https://doi.org/10.3390/insects16050455 - 25 Apr 2025

Abstract

Pesticides are considered a major factor in the decline of bee populations. Flupyradifurone, a novel insecticide, is believed to be relatively ‘bee-safe’. This study aims to evaluate the acute and chronic toxicity of flupyradifurone and assess its risks to both commercial bumblebee Bombus [...] Read more.

Pesticides are considered a major factor in the decline of bee populations. Flupyradifurone, a novel insecticide, is believed to be relatively ‘bee-safe’. This study aims to evaluate the acute and chronic toxicity of flupyradifurone and assess its risks to both commercial bumblebee Bombus terrestris and the Asian native species B. lantschouensis. Oral toxicity tests demonstrated species-specific sensitivity, with B. lantschouensis exhibiting 5.4-fold higher acute toxicity (72-h LD₅₀: 5.1 μg/bee vs. 28 μg/bee) and 3-fold lower chronic toxicity (No Observed Adverse Effect Concentration, NOAEC: 20 μg/mL vs. 60 μg/mL) compared to B. terrestris. Risk assessments indicated low Hazard Quotients (HQ) of 4 for B. terrestris and 20 for B. lantschouensis. However, the Exposure Toxicity Ratio (ETR) values from both screening and first-tier assessments exceeded the trigger levels, necessitating further testing. This study provides crucial data on the acute and chronic toxic effects of flupyradifurone and highlights the need for more comprehensive insecticide risk assessments, particularly for non-Apis pollinators, to better protect these vital species. Full article

(This article belongs to the Special Issue Bumblebee Biology and Ecology)

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