Insects

20 pages, 2840 KiB

Open AccessArticle

Functional Analysis of BmHemolin in the Immune Defense of Silkworms

by Long He, Lijing Liu, Huawei Liu, Xin Tang, Yide Meng, Hui Xie, Lin Zhu, Qingyou Xia and Ping Zhao

Insects 2025, 16(8), 778; https://doi.org/10.3390/insects16080778 - 29 Jul 2025

Abstract

Hemolin has been identified as a crucial immune gene in insect immune defense. The silkworm is susceptible to infections by pathogenic microorganisms when reared on artificial diets. In this study, through comparative analysis of the expression patterns of BmHemolin in silkworms fed on [...] Read more.

Hemolin has been identified as a crucial immune gene in insect immune defense. The silkworm is susceptible to infections by pathogenic microorganisms when reared on artificial diets. In this study, through comparative analysis of the expression patterns of BmHemolin in silkworms fed on mulberry leaves and artificial diets, we found that the expression of BmHemolin was significantly upregulated in silkworms reared on artificial diets, and this upregulation was highly likely induced by pathogenic microorganisms. Further interaction analysis revealed that BmHemolin could bind to pathogenic microorganisms and form aggregates. Meanwhile, BmHemolin enhanced the melanization and aggregation of hemocytes. Subsequent in vitro antibacterial experiments showed that BmHemolin had the ability to inhibit the growth of Escherichia coli. In vivo clearance experiments demonstrated that BmHemolin facilitated the clearance of pathogens in the body. Moreover, CRISPR/Cas9-mediated knockout of the BmHemolin gene led to the downregulation of antimicrobial peptides and phagocytosis-related factors, while an excess of BmHemolin could enhance the expression of these genes, thereby improving the silkworm’s immune resistance to Enterococcus mundtii and increasing survival rates. In summary, our research demonstrates that BmHemolin played a pivotal role in both humoral and cellular immunity in the silkworm, thereby defending against pathogen invasion. Full article

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

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16 pages, 1251 KiB

Open AccessArticle

Demographic Parameters and Life History Traits of Neoseiulus cucumeris (Oudemans) (Acari: Phytoseiidae) Influenced by Different Temperatures and Two Types of Food

by Mohammed M. E. Elmoghazy, Eslam Kamal Fahmy, Tagwa Salah Ahmed Mohammed Ali, Mohamed El-Sherbiny, Rasha Hamed Al-Serwi, Moaz Abulfaraj and Dalia M. A. Elsherbini

Insects 2025, 16(8), 777; https://doi.org/10.3390/insects16080777 - 29 Jul 2025

Abstract

Studying the nutritional ecology of Neoseiulus cucumeris (Oudemans) at different temperatures is a fundamental tool for improving mass production for use in biological control of pest mites. The current research studied the impact of both food types and temperatures on the life history [...] Read more.

Studying the nutritional ecology of Neoseiulus cucumeris (Oudemans) at different temperatures is a fundamental tool for improving mass production for use in biological control of pest mites. The current research studied the impact of both food types and temperatures on the life history and demographic parameters of the predator mite N. cucumeris. Mite cultures in the laboratory were developed using Tetranychus urticae Koch, and N. cucumeris was collected from field plants. The developmental stages of N. cucumeris fed on date palm pollen and the immature stages of T. urticae were investigated in a laboratory setting at different temperatures. Our research revealed that N. cucumeris readily accepted both food types at all the tested temperatures. The developmental stages and adult longevity of N. cucumeris, both female and male, decreased dramatically when the temperature increased from 18 °C to 34 °C. The net reproductive rate (R₀) reached its greatest values of 22.52 and 9.72 offspring/individual at 26 °C, and the intrinsic rate of increase (r_m) reached its maximum values of 0.17 and 0.13 day⁻¹ at 34 °C and minimum of 0.12 and 0.10 day⁻¹ at 18 °C, when fed on date palm pollen and immature stages of T. urticae, respectively. Conversely, the average generation time (T) showed a notable reduction from 22.48 to 16.48 and 20.88 to 16.76 days, accompanied by an upsurge in temperature from 18 °C to 34 °C, when fed on date palm pollen and immature stages of T. urticae, respectively. The finite rate of growth (λ) exhibited distinct variations, reaching its highest value at 34 °C, 26 °C, and 18 °C when fed on date palm pollen and immature stages of T. urticae, respectively. From these results, we can conclude that N. cucumeris was successfully fed date palm pollen as an alternate source of nourishment. In addition, the immature stages of T. urticae are suitable as food sources for N. cucumeris because they shorten the mean generation time. Therefore, the success of mass-rearing the predator mite N. cucumeris on a different, less expensive diet, such as date palm pollen, and determining the most suitable temperature for it has increased its spread as a biocontrol agent. Full article

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

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21 pages, 1274 KiB

Open AccessArticle

Detection and Quantification of House Crickets (Acheta domesticus) in the Gut of Yellow Mealworm (Tenebrio molitor) Larvae Fed Diets Containing Cricket Flour: A Comparison of qPCR and ddPCR Sensitivity

by Pavel Vejl, Agáta Čermáková, Martina Melounová, Daniela Čílová, Kamila Zdeňková, Eliška Čermáková and Jakub Vašek

Insects 2025, 16(8), 776; https://doi.org/10.3390/insects16080776 - 28 Jul 2025

Abstract

Due to their nutritional value and sustainability, edible insect-based foods are gaining popularity in Europe. Their use is regulated by EU legislation, which defines authorised species and sets labelling requirements. Molecular tools are being developed to authenticate such products. In this study, yellow [...] Read more.

Due to their nutritional value and sustainability, edible insect-based foods are gaining popularity in Europe. Their use is regulated by EU legislation, which defines authorised species and sets labelling requirements. Molecular tools are being developed to authenticate such products. In this study, yellow mealworm (Tenebrio molitor) larvae authorised for human consumption were fed wheat flour-based diets containing varying proportions of house cricket (Acheta domesticus) flour for 21 days. This was followed by a 48 h starvation period to assess the persistence of insect DNA in the digestive tract. Two novel, species-specific, single-copy markers were designed: ampd gene for the Acheta domesticus and MyD88 gene for the Tenebrio molitor. These were applied using qPCR and ddPCR. Both methods successfully detected cricket DNA in the guts of starved larvae. Linear regression analysis revealed a strong, statistically significant correlation between the proportion of Acheta domesticus flour in the diet and the normalised relative quantity of DNA. ddPCR proved to be more sensitive than qPCR, particularly in the detection of low DNA levels. These results suggest that the presence of DNA from undeclared insect species in edible insects may be indicative of their diet rather than contamination or adulteration. This highlights the importance of contextual interpretation in food authenticity testing. Full article

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

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12 pages, 7580 KiB

Open AccessArticle

Three New Species of Nolidae (Lepidoptera) from Palawan Island, the Philippines, with Checklists of the Genera Wittonola, Aeneanola, and Evonima

by Yeong-Bin Cha, Ulziijargal Bayarsaikhan, Jae-Ho Ko, Tak-Gi Lee, Chang-Moon Jang, Hanul Kim, Jeong-Nam Kim and Yang-Seop Bae

Insects 2025, 16(8), 775; https://doi.org/10.3390/insects16080775 - 28 Jul 2025

Abstract

This paper contains three newly recorded genera (Wittonola László, Ronkay & Ronkay, 2015; Aeneanola László, Ronkay & Ronkay, 2013; and Evonima Walker, 1865) and each new species (W. bicyanasp. nov., A. crassasp. nov., and E. palawanensissp. [...] Read more.

This paper contains three newly recorded genera (Wittonola László, Ronkay & Ronkay, 2015; Aeneanola László, Ronkay & Ronkay, 2013; and Evonima Walker, 1865) and each new species (W. bicyanasp. nov., A. crassasp. nov., and E. palawanensissp. nov.) from Palawan, the Philippines. We provide illustrations of three new species and their genitalia, photographs of collecting sites, and checklists of the three genera. Full article

(This article belongs to the Special Issue Revival of a Prominent Taxonomy of Insects)

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14 pages, 2165 KiB

Open AccessArticle

Evaluation on Biocontrol Efficacy of Episyrphus balteatus De Geer (Diptera: Syrphidae) Against Aphis craccivora, Myzus persicae, and Megoura crassicauda

by Shanshan Jiang, Hui Li and Kongming Wu

Insects 2025, 16(8), 774; https://doi.org/10.3390/insects16080774 - 28 Jul 2025

Abstract

Larvae of Episyrphus balteatus De Geer (Diptera: Syrphidae) are important natural enemies of common agricultural pests such as aphids (Hemiptera: Aphididae). This well-known aphidophagous flower fly is used as a biological control agent. The predatory functional responses, control efficacy, and oviposition and predatory [...] Read more.

Larvae of Episyrphus balteatus De Geer (Diptera: Syrphidae) are important natural enemies of common agricultural pests such as aphids (Hemiptera: Aphididae). This well-known aphidophagous flower fly is used as a biological control agent. The predatory functional responses, control efficacy, and oviposition and predatory preferences of E. balteatus against Aphis craccivora Koch, Myzus persicae Sulzer, and Megoura crassicauda Mordvilko were systematically determined through controlled laboratory experiments. The best functional response model of both second- and third-instar E. balteatus larvae to these three aphid species was the Holling type III model, except for the third-instar larvae to A. craccivora, for which the Holling type II model was superior. The A. craccivora population decline rates for ratios of 1:500 and 1:1000 were 94.67% and 100.00% on day 12 after inoculation; the M. persicae population decline rates for ratios of 1:2000 and 1:4000 reached 96.67% and 95.42% by day 12, and the M. crassicauda population at a ratio of 1:250 was completely eliminated by day 9, achieving a 100.00% population decline rate. The oviposition and predatory preferences of E. balteatus were consistent, in that it preferred M. crassicauda for oviposition and had a positive predatory preference for this aphid species. These results provide scientific evidence for the biological control strategy of E. balteatus against these aphids. Full article

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

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20 pages, 1398 KiB

Open AccessArticle

Effects of Multi-Generational Rearing on Job’s Tears on the Performance and Host Plant Preference of Spodoptera frugiperda (Lepidoptera: Noctuidae)

by Feng-Luan Yao, Yao-Yao Wu, Gao-Ke Lei, Xiao-Yan Huang, Xue-Ling Ding, Xue-Song Lu, Yu Zheng and Yu-Xian He

Insects 2025, 16(8), 773; https://doi.org/10.3390/insects16080773 - 28 Jul 2025

Abstract

The fall armyworm (FAW), Spodoptera frugiperda, is a highly polyphagous pest posing a major threat to Poaceae crops, particularly corn (Zea mays), in China. However, its ability to adapt to Job’s tears (Coix lacryma-jobi), an edible and medicinal [...] Read more.

The fall armyworm (FAW), Spodoptera frugiperda, is a highly polyphagous pest posing a major threat to Poaceae crops, particularly corn (Zea mays), in China. However, its ability to adapt to Job’s tears (Coix lacryma-jobi), an edible and medicinal Poaceae species, under continuous rearing remains insufficiently understood. In this study, FAW survival, development, and reproduction were assessed over eight generations on two cultivars of Job’s tears, ‘Cuiyi 1’ and ‘Puyi 6’. Feeding and oviposition preferences were also examined in FAW populations reared on ‘Puyi 6’ by offering corn and ‘Puyi 6’ as hosts. Sustained rearing for five to eight generations on both cultivars significantly increased population fitness, with greater improvements observed in the ‘Puyi 6’ group. FAW reared on corn or ‘Puyi 6’ for two generations exhibited strong preferences for corn, whereas those reared on ‘Puyi 6’ for five to eight generations showed no significant host preference. These findings suggest that transgenerational adaptation markedly improved FAW performance and acceptance of Job’s tears, underscoring the need for intensified monitoring of FAW dynamics during the cultivation of Job’s tears. Full article

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

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12 pages, 1515 KiB

Open AccessArticle

Expression of Heat Shock Protein 90 Genes Induced by High Temperature Mediated Sensitivity of Aphis glycines Matsumura (Hemiptera: Aphididae) to Insecticides

by Xue Han, Yulong Jia, Changchun Dai, Xiaoyun Wang, Jian Liu and Zhenqi Tian

Insects 2025, 16(8), 772; https://doi.org/10.3390/insects16080772 - 28 Jul 2025

Abstract

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is a major pest of soybean fields. While high-temperature stress induced by global warming can initially suppress aphid populations, these pests may eventually adapt, leading to more severe infestations and crop damage. Heat shock proteins (HSPs), [...] Read more.

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is a major pest of soybean fields. While high-temperature stress induced by global warming can initially suppress aphid populations, these pests may eventually adapt, leading to more severe infestations and crop damage. Heat shock proteins (HSPs), which are upregulated in response to heat stress to protect aphid development, also confer tolerance to other abiotic stressors, including insecticides. To investigate the role of HSPs in insecticide resistance in A. glycines, we analyzed the expression profiles of three AgHsp90 genes (AgHsp75, AgHsp83, and AgGrp94) following exposure to high temperatures and insecticides. Functional validation was performed using RNA interference (RNAi) to silence AgHsp90 genes. Our results demonstrated that AgHsp90 genes were significantly upregulated under both heat and insecticide stress conditions. Furthermore, after feeding on dsRNA of AgHsp90 genes, mortality rates of A. glycines significantly increased when exposed to imidacloprid and lambda-cyhalothrin. This study provides evidence that AgHsp90 genes play a crucial role in mediating thermal tolerance and insecticide resistance in A. glycines. Full article

(This article belongs to the Special Issue RNAi in Insect Physiology)

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12 pages, 10018 KiB

Open AccessArticle

Unraveling the Compound Eye Design of the Diurnal Moth Histia flabellicornis (Lepidoptera: Zygaenidae)

by Qing-Xiao Chen, Ya-Fei Li and Yun-Zhu Huo

Insects 2025, 16(8), 771; https://doi.org/10.3390/insects16080771 - 27 Jul 2025

Abstract

Lepidoptera typically exhibit a dichotomy in compound eye design: diurnal butterflies possess apposition eyes for high resolution in bright light, whereas nocturnal moths have superposition eyes for enhanced sensitivity under dim conditions. However, exceptions, particularly among diurnal moths, challenge this pattern and offer [...] Read more.

Lepidoptera typically exhibit a dichotomy in compound eye design: diurnal butterflies possess apposition eyes for high resolution in bright light, whereas nocturnal moths have superposition eyes for enhanced sensitivity under dim conditions. However, exceptions, particularly among diurnal moths, challenge this pattern and offer insights into the evolution of compound eyes in Lepidoptera. In this study, we investigated the compound eye design of the diurnal moth Histia flabellicornis (Fabricius) using light, scanning, and transmission electron microscopy to determine whether it has superposition or apposition eyes, and to quantitatively analyze the structural features and visual acuity. Our results reveal that H. flabellicornis possesses apposition-type compound eyes composed of over 2000 ommatidia, each comprising a cornea, a crystalline cone, nine retinula cells forming a fused rhabdom, and a few isolated tracheoles. The calculated interommatidial angles (Δϕ = 4.08°) and the eye parameter P (P = 1.74) suggest a visual system adapted to moderate light conditions, balancing spatial resolution with photon capture. These findings confirm the presence of apposition eyes in H. flabellicornis, supporting the moth’s adaptation to diurnal behavior and contributing to understanding the evolutionary diversification of compound eye designs in Lepidoptera. Full article

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

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22 pages, 3852 KiB

Open AccessArticle

The Study on Culicoides: The Environment They Live in and Trypanosomatids They Coexist

by Margarita Kazak, Kristina Valavičiūtė-Pocienė and Rasa Bernotienė

Insects 2025, 16(8), 770; https://doi.org/10.3390/insects16080770 - 27 Jul 2025

Abstract

Information on Culicoides transmitted parasites, especially trypanosomatids, infecting animals and insects, is scarce. Our goal was to clarify the seasonal patterns of both Culicoides and trypanosomatids detected in these insects and the relationships between Culicoides abundance and meteorological parameters. UV light traps were [...] Read more.

Information on Culicoides transmitted parasites, especially trypanosomatids, infecting animals and insects, is scarce. Our goal was to clarify the seasonal patterns of both Culicoides and trypanosomatids detected in these insects and the relationships between Culicoides abundance and meteorological parameters. UV light traps were used to collect biting midges in four study sites in 2022–2023; collected Culicoides females were dissected and analyzed using microscopy and PCR-based methods. Out of 1631 parous Culicoides females belonging to 14 different species, 6.5% were found to be infected with trypanosomatids (5.0% with at least three Trypanosoma species and 1.5% with monoxenous parasites). The highest Culicoides abundance was detected in June. The prevalence of trypanosomatids in biting midges increased during the summer (5.3% in June, 8.8% in July, and 11.2% in August). Temperature was recorded to be a presiding environmental gradient structuring Culicoides species composition, while wind speed and precipitation explained little of the variation. Our results indicate that both avian and mammalian trypanosomes can be found in these insects, although further research is needed to better understand the development of these parasites in biting midges and Culicoides vectorial capacity. Full article

(This article belongs to the Collection Advances in Diptera Biology)

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14 pages, 1829 KiB

Open AccessArticle

Investigating the Spatial Biases and Temporal Trends in Insect Pollinator Occurrence Data on GBIF

by Ehsan Rahimi and Chuleui Jung

Insects 2025, 16(8), 769; https://doi.org/10.3390/insects16080769 - 26 Jul 2025

Abstract

Research in biogeography, ecology, and biodiversity hinges on the availability of comprehensive datasets that detail species distributions and environmental conditions. At the forefront of this endeavor is the Global Biodiversity Information Facility (GBIF). This study focuses on investigating spatial biases and temporal trends [...] Read more.

Research in biogeography, ecology, and biodiversity hinges on the availability of comprehensive datasets that detail species distributions and environmental conditions. At the forefront of this endeavor is the Global Biodiversity Information Facility (GBIF). This study focuses on investigating spatial biases and temporal trends in insect pollinator occurrence data within the GBIF dataset, specifically focusing on three pivotal pollinator groups: bees, hoverflies, and butterflies. Addressing these gaps in GBIF data is essential for comprehensive analyses and informed pollinator conservation efforts. We obtained occurrence data from GBIF for seven bee families, six butterfly families, and the Syrphidae family of hoverflies in 2024. Spatial biases were addressed by eliminating duplicate records with identical latitude and longitude coordinates. Species richness was assessed for each family and country. Temporal trends were examined by tallying annual occurrence records for each pollinator family, and the diversity of data sources within GBIF was evaluated by quantifying unique data publishers. We identified initial occurrence counts of 4,922,390 for bees, 1,703,131 for hoverflies, and 31,700,696 for butterflies, with a substantial portion containing duplicate records. On average, 81.4% of bee data, 77.2% of hoverfly data, and 65.4% of butterfly data were removed post-duplicate elimination for dataset refinement. Our dataset encompassed 9286 unique bee species, 2574 hoverfly species, and 17,895 butterfly species. Our temporal analysis revealed a notable trend in data recording, with 80% of bee and butterfly data collected after 2022, and a similar threshold for hoverflies reached after 2023. The United States, Germany, the United Kingdom, and Sweden consistently emerged as the top countries for occurrence data across all three groups. The analysis of data publishers highlighted iNaturalist.org as a top contributor to bee data. Overall, we uncovered significant biases in the occurrence data of pollinators from GBIF. These biases pose substantial challenges for future research on pollinator ecology and biodiversity conservation. Full article

(This article belongs to the Special Issue Insect Pollinators and Pollination Service Provision)

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14 pages, 911 KiB

Open AccessArticle

Physiological Response of Tribolium castaneum to CO₂ Controlled Atmosphere Stress Under Trehalose Feeding

by Yuya Zhang, Shangrong Hu, Min Zhou, Xinyi Zhang, Liwen Guan, Yanfei Zhou, Jun Lv and Bin Tang

Insects 2025, 16(8), 768; https://doi.org/10.3390/insects16080768 - 26 Jul 2025

Abstract

This study investigated the physiological regulatory mechanisms by which exogenous trehalose intake enhances the adaptation of the global stored-grain pest T. castaneum to high-concentration carbon dioxide (CO₂) stress. By supplementing exogenous trehalose under high-CO₂ controlled atmosphere stress, we measured the [...] Read more.

This study investigated the physiological regulatory mechanisms by which exogenous trehalose intake enhances the adaptation of the global stored-grain pest T. castaneum to high-concentration carbon dioxide (CO₂) stress. By supplementing exogenous trehalose under high-CO₂ controlled atmosphere stress, we measured the activities of key detoxification enzymes (e.g., carboxylesterase and cytochrome P450) and the levels of carbohydrate substances (e.g., glycogen, glucose, and trehalose). The results demonstrated that trehalose feeding significantly alleviated CO₂ induced mortality in T. castaneum and prolonged their survival time. In terms of detoxification metabolism, a trehalose-rich diet significantly reduced the activities of cytochrome P450 and carboxylesterase, while the glucose content in the beetles decreased markedly. These findings indicate that trehalose accumulation mitigates physiological damage caused by high-CO₂ stress in T. castaneum. Furthermore, exogenous trehalose intake did not disrupt carbohydrate metabolic homeostasis in the beetles, as trehalase activity and the levels of various carbohydrates remained relatively stable. This study elucidates the role of trehalose metabolism in T. castaneum’s adaptation to high-CO₂ environments, providing a theoretical foundation for optimizing controlled atmosphere grain storage technology and developing novel pest control strategies. Full article

(This article belongs to the Special Issue Controlling Insect Pests in Postharvest Agricultural Products Using Non-Chemical Methods)

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15 pages, 1299 KiB

Open AccessArticle

Host-Dependent Variation in Tetranychus urticae Fitness and Microbiota Composition Across Strawberry Cultivars

by Xu Zhang, Hongjun Yang, Zhiming Yan, Yuanhua Wang, Quanzhi Wang, Shimei Huo, Zhan Chen, Jialong Cheng and Kun Yang

Insects 2025, 16(8), 767; https://doi.org/10.3390/insects16080767 - 25 Jul 2025

Abstract

Tetranychus urticae, commonly known as the two-spotted spider mite, is a highly adaptable and polyphagous arthropod in the family Tetranychidae, capable of feeding on over 1200 plant species, including strawberries (Fragaria × ananassa Duch.). The fitness and microbiota of herbivorous arthropods [...] Read more.

Tetranychus urticae, commonly known as the two-spotted spider mite, is a highly adaptable and polyphagous arthropod in the family Tetranychidae, capable of feeding on over 1200 plant species, including strawberries (Fragaria × ananassa Duch.). The fitness and microbiota of herbivorous arthropods can vary significantly across different plant species and cultivars. In this study, we investigated the fecundity, longevity, growth rate, and microbiota composition of T. urticae reared on seven Chinese strawberry cultivars: Hongyan (HY), Yuexiu (YX), Tianshi (TS), Ningyu (NY), Xuetu (XT), Zhangjj (ZJ), and Xuelixiang (XLX). Our findings revealed significant differences among cultivars: mites reared on the XT cultivar exhibited the highest fecundity (166.56 ± 7.82 eggs), while those on XLX had the shortest pre-adult period (7.71 ± 0.13 days). Longevity was significantly extended in mites reared on XLX, XT, and NY cultivars (25.95–26.83 days). Microbiota analysis via 16S rRNA sequencing showed that Proteobacteria dominated (>89.96% abundance) across all mite groups, with Wolbachia as the predominant symbiont (89.58–99.19%). Male mites exhibited higher bacterial diversity (Shannon and Chao1 indices) than females, though Wolbachia abundance did not differ significantly between sexes or cultivars. Functional predictions highlighted roles of microbiota in biosynthesis, detoxification, and energy metabolism. These findings underscore the influence of host plant variety on T. urticae fitness and microbiota composition, suggesting potential strategies for breeding resistant strawberry cultivars and leveraging microbial interactions for pest management. Full article

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17 pages, 3503 KiB

Open AccessArticle

Functional Analysis of NPC2 in Alarm Pheromone Recognition by the Red Imported Fire Ant, Solenopsis invicta (Formicidae: Solenopsis)

by Peng Lin, Jiacheng Shen, Xinyi Jiang, Fenghao Liu and Youming Hou

Insects 2025, 16(8), 766; https://doi.org/10.3390/insects16080766 - 25 Jul 2025

Abstract

The red imported fire ant (Solenopsis invicta) is a dangerous invasive insect. These ants rely on releasing an alarm pheromone, mainly composed of 2-ethyl-3,6-dimethylptrazine (EDMP), to warn nestmates of danger and trigger group defense or escape behaviors. This study found two [...] Read more.

The red imported fire ant (Solenopsis invicta) is a dangerous invasive insect. These ants rely on releasing an alarm pheromone, mainly composed of 2-ethyl-3,6-dimethylptrazine (EDMP), to warn nestmates of danger and trigger group defense or escape behaviors. This study found two NPC2 proteins in the ant antennae: SinvNPC2a and SinvNPC2b. SinvNPC2a was highly expressed in the antennae; phylogenetic analysis also suggests that SinvNPC2 likely possesses conserved olfactory recognition functions. By knocking down the SinvNPC2a gene, we found that the electrophysiological response of ant antennae to EDMP became weaker. More importantly, ants lacking SinvNPC2a showed significantly reduced movement range and speed when exposed to EDMP, compared to normal ants not treated with RNAi. These ants did not spread out quickly. Furthermore, tests showed that the purified SinvNPC2a protein could directly bind to EDMP molecules. Computer modeling also showed that they fit together tightly. These findings provide direct evidence that the SinvNPC2a protein plays a key role in helping fire ants detect the EDMP alarm pheromone. It enables the ants to sense this chemical signal, allowing ant colonies to respond quickly. Understanding this mechanism improves our knowledge of how insects smell things. It also suggests a potential molecular target for developing new methods to control fire ants, such as using RNAi to block its function. Full article

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

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7 pages, 408 KiB

Open AccessBrief Report

A Note on the Honey Bee Parasitic Phorid Fly (Apocephalus borealis Brues) in an Urban Ecosystem

by Lioh Jaboeuf, Miguel Cabrera, Jenny Hoffmann, Emma Gallagher, Laura Byrne, John F. Mejía and Mitzy F. Porras

Insects 2025, 16(8), 765; https://doi.org/10.3390/insects16080765 - 25 Jul 2025

Abstract

The honey bee is a crucial pollinator in urban ecosystems but faces multiple challenges, including habitat degradation, pollution, and parasitism by species such as the phorid fly, Apocephalus borealis Brues (Diptera: Phoridae). This study investigated honey bee abundance and the percentage of A. [...] Read more.

The honey bee is a crucial pollinator in urban ecosystems but faces multiple challenges, including habitat degradation, pollution, and parasitism by species such as the phorid fly, Apocephalus borealis Brues (Diptera: Phoridae). This study investigated honey bee abundance and the percentage of A. borealis parasitism in an urban environment in San Francisco, California. We monitored six sites weekly for six months using two sampling methods. Individual bees were weighed and observed for parasitoid emergence under controlled laboratory conditions. Our results indicate fluctuations in honey bee parasitism by A. borealis from September 2024 to May 2025, with four distinct peaks occurring in mid-September, February, late March, and early May. The highest parasitism rates exceeded 50% in early May, coinciding with increased temperatures and drops in relative humidity. These results suggest a potential link between abiotic conditions and parasitoid activity, highlighting the importance of long-term monitoring to understand the seasonal dynamics of host–parasite interactions in urban environments. Full article

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

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21 pages, 1355 KiB

Open AccessArticle

Nationwide Screening for Arthropod, Fungal, and Bacterial Pests and Pathogens of Honey Bees: Utilizing Environmental DNA from Honey Samples in Australia

by Gopika Bhasi, Gemma Zerna and Travis Beddoe

Insects 2025, 16(8), 764; https://doi.org/10.3390/insects16080764 - 25 Jul 2025

Abstract

The European honey bee (Apis mellifera) significantly contributes to Australian agriculture, especially in honey production and the pollination of key crops. However, managed bee populations are declining due to pathogens, agrochemicals, poor forage, climate change, and habitat loss. Major threats include [...] Read more.

The European honey bee (Apis mellifera) significantly contributes to Australian agriculture, especially in honey production and the pollination of key crops. However, managed bee populations are declining due to pathogens, agrochemicals, poor forage, climate change, and habitat loss. Major threats include bacteria, fungi, mites, and pests. With the increasing demand for pollination and the movement of bee colonies, monitoring these threats is essential. It has been demonstrated that honey constitutes an easily accessible source of environmental DNA. Environmental DNA in honey comes from all organisms that either directly or indirectly aid in its production and those within the hive environments. In this study, we extracted eDNA from 135 honey samples and tested for the presence of DNA for seven key honey bee pathogens and pests—Paenibacillus larvae, Melissococcus plutonius (bacterial pathogens), Nosema apis, Nosema ceranae (microsporidian fungi), Ascosphaera apis (fungal pathogen), Aethina tumida, and Galleria mellonella (arthropod pests) by using end-point singleplex and multiplex PCR assays. N. ceranae emerged as the most prevalent pathogen, present in 57% of the samples. This was followed by the pests A. tumida (40%) and G. mellonella (37%), and the pathogens P. larvae (21%), N. apis (19%), and M. plutonius (18%). A. apis was detected in a smaller proportion of the samples, with a prevalence of 5%. Additionally, 19% of the samples tested negative for all pathogens and pests analysed. The data outlines essential information about the prevalence of significant arthropod, fungal, and bacterial pathogens and pests affecting honey bees in Australia, which is crucial for protecting the nation’s beekeeping industry. Full article

(This article belongs to the Special Issue Recent Advances in Bee Parasite, Pathogen, and Predator Interactions)

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23 pages, 8883 KiB

Open AccessArticle

Venom IMP-L2 from the Ectoparasitoid Scleroderma guani Regulates the IIS/TOR Pathway in Tenebrio molitor

by Wenxiu Wang, Zhiquan Zhang, Xuemin Ren, Chaoyan Wu and Jiaying Zhu

Insects 2025, 16(8), 763; https://doi.org/10.3390/insects16080763 - 24 Jul 2025

Abstract

Parasitoid venom significantly influences host physiology and development. Our previous research identified high levels of insulin-binding protein IMP-L2 in the venom of Scleroderma guani. IMP-L2 may inhibit the insulin/insulin-like growth factor signaling (IIS) cascade by competitively binding insulin-like peptides (ILPs) with insulin [...] Read more.

Parasitoid venom significantly influences host physiology and development. Our previous research identified high levels of insulin-binding protein IMP-L2 in the venom of Scleroderma guani. IMP-L2 may inhibit the insulin/insulin-like growth factor signaling (IIS) cascade by competitively binding insulin-like peptides (ILPs) with insulin receptor (InR). However, how to regulate IIS transduction is unclear. We speculate that venom-derived IMP-L2 may bind ILPs to inhibit IIS transduction. Consequently, we investigated the regulation of the IIS/TOR pathway by venom-derived IMP-L2. An expression analysis of IIS/TOR pathway genes across various developmental stages of Tenebrio molitor demonstrated that this pathway governs the entire developmental process. By examining gene expression before and after parasitism, we determined that S. guani predominantly inhibits TOR pathway signaling in T. molitor post-parasitism. Bioinformatics and expression analyses revealed that IMP-L2 is critically involved in Hymenoptera insects, exhibiting high expression in the venom apparatus, and is upregulated in response to S. guani parasitism factors. Additionally, recombinant IMP-L2 was produced via eukaryotic expression. Finally, the recombinant IMP-L2 was found to inhibit the TOR and IIS/TOR signaling pathways at early (6 h) and late (24 h) stages post-injection. Knockdown of IMP-L2 in S. guani parasitized T. molitor pupae, resulting in accelerated death of T. molitor. During parasitism, S. guani may suppress host growth and development by modulating the IIS/TOR signaling pathway through venom-derived IMP-L2, potentially affecting host lifespan. Full article

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

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19 pages, 11648 KiB

Open AccessArticle

Edge Effects on the Spatial Distribution and Diversity of Drosophilidae (Diptera) Assemblages in Deciduous Forests of Central European Russia

by Nikolai G. Gornostaev, Alexander B. Ruchin, Oleg E. Lazebny, Alex M. Kulikov and Mikhail N. Esin

Insects 2025, 16(8), 762; https://doi.org/10.3390/insects16080762 - 24 Jul 2025

Abstract

In the forest ecosystems of Central European Russia, the influence of forest edges on the spatial distribution of Drosophilidae was studied for the first time. The research was conducted during the period of 2021–2022 in the Republic of Mordovia. Beer traps baited with [...] Read more.

In the forest ecosystems of Central European Russia, the influence of forest edges on the spatial distribution of Drosophilidae was studied for the first time. The research was conducted during the period of 2021–2022 in the Republic of Mordovia. Beer traps baited with fermented beer and sugar were used to collect Drosophilidae. Two study plots were selected, differing in their forest edges, tree stands, and adjacent open ecosystems. In both cases, the forest directly bordered an open ecosystem. Edges serve as transitional biotopes, where both forest and meadow (open area) faunas coexist. Knowing that many drosophilid species prefer forest habitats, we designated forest interior sites as control points. Traps were set at heights of 1.5 m (lower) and 7.5 m (upper) on trees. A total of 936 specimens representing 27 species were collected. Nine species were common across all traps, while ten species were recorded only once. At the forest edges, 23 species were captured across both heights, compared to 19 species in the forest interiors. However, the total abundance at the forest edges was 370 specimens, while it was 1.5 times higher in the forest interiors. Both abundance and species richness varied between plots. Margalef’s index was higher at the forest edges than in the forest interiors, particularly at 1.5 m height at the edge and at 7.5 m height in the forest interior. Shannon and Simpson indices showed minimal variation across traps at different horizontal and vertical positions. The highest species diversity was observed among xylosaprobionts (9 species) and mycetophages (8 species). All ecological groups were represented at the forest edges, whereas only four groups were recorded in the forest interiors, with the phytosaprophagous species Scaptomyza pallida being absent. In general, both species richness and drosophilid abundance increased in the lower strata, both at the forest edge and within the interior. Using the R package Indicspecies, we identified Gitona distigma as an indicator species for the forest edge and Scaptodrosophila rufifrons as an indicator for the forest interior in the lower tier for both plots. In addition, Drosophila testacea, D. phalerata, and Phortica semivirgo were found to be indicator species for the lower tier in both plots, while Leucophenga quinquemaculata was identified as an indicator species for the upper tier at the second plot. Full article

(This article belongs to the Topic Arthropod Biodiversity: Ecological and Functional Aspects, 2nd Edition)

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14 pages, 3308 KiB

Open AccessArticle

Dietary Sodium Butyrate Supplementation Enhances Silkworm Silk Yield by Simultaneously Promoting Larval Growth and Silk Gland Development

by Xiaoxiao Ren, Xingjiang He, Zhanfeng Ye, Zhuo Qing, Wanjun Yang, Chaobin Luo and Dan Xing

Insects 2025, 16(8), 761; https://doi.org/10.3390/insects16080761 - 24 Jul 2025

Abstract

Silk yield enhancement in sericulture has plateaued. Sodium butyrate (NaB) is known to improve production performance in livestock and poultry, yet its effects on silkworm silk yield remain uncharacterized. Here, we evaluated the impact of dietary NaB supplementation on silkworm growth, silk gland [...] Read more.

Silk yield enhancement in sericulture has plateaued. Sodium butyrate (NaB) is known to improve production performance in livestock and poultry, yet its effects on silkworm silk yield remain uncharacterized. Here, we evaluated the impact of dietary NaB supplementation on silkworm growth, silk gland development, and cocoon output. Mulberry leaves were immersed in NaB solutions at concentrations of 0, 2.5, 5, 10, 20, 40, or 80 mM, and subsequently provided as feed to third- to fifth-instar larvae. Among these, 10 mM NaB treatment most effectively promoted larval and pupal weight gain and increased food intake. Phenotypic and economic trait analyses revealed that 10 mM NaB treatment significantly enlarged the silk gland and boosted overall silk yield. Mechanistically, NaB enhanced body growth by increasing feeding intake and influencing the juvenile hormone and ecdysteroid signaling pathways; moreover, it promoted DNA replication in silk gland cells, thereby influencing silk gland development. Taken together, our findings demonstrate that dietary supplementation with an appropriate concentration of NaB concurrently enhances body growth and silk gland development, leading to higher silk production, and underscore the potential of short-chain fatty acid salts in advancing sericulture. Full article

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

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14 pages, 1482 KiB

Open AccessArticle

Development of Forensically Important Megaselia scalaris and Dohrniphora cornuta (Diptera: Phoridae) in Sandy Loam Under Constant Moisture and Different Temperature Regimes

by Wei Han, Dianxing Feng and Yanan Tang

Insects 2025, 16(8), 760; https://doi.org/10.3390/insects16080760 - 24 Jul 2025

Abstract

The Phoridae are relatively common insects on buried corpses, and their developmental information plays an important role in estimating post-burial interval (PBI) for buried corpses. Developmental time, larval body length, and intra-puparial developmental changes in two forensically important phorid flies, Megaselia scalaris (Loew, [...] Read more.

The Phoridae are relatively common insects on buried corpses, and their developmental information plays an important role in estimating post-burial interval (PBI) for buried corpses. Developmental time, larval body length, and intra-puparial developmental changes in two forensically important phorid flies, Megaselia scalaris (Loew, 1866) and Dohrniphora cornuta (Bigot, 1857) (Diptera: Phoridae), were studied in sandy loam with 20% moisture content at 18, 21, 24, and 27 °C. The juvenile development time of both species decreased with increasing temperature. At 18, 21, 24, and 27 °C, the larval development time of M. scalaris was 165.18 ± 2.96 h, 119.72 ± 2.74 h, 90.28 ± 3.54 h, and 63.04 ± 3.45 h, respectively, with corresponding intra-puparial development times of 606.67 ± 3.38 h, 404.62 ± 3.28 h, 269.22 ± 6.04 h, and 237.57 ± 3.41 h. For D. cornuta, the larval development time was 249.37 ± 4.88 h, 154.59 ± 1.81 h, 108.80 ± 2.65 h, and 86.04 ± 3.91 h, respectively, while the intra-puparial development time was 593.37 ± 4.75 h, 414.23 ± 3.51 h, 261.02 ± 3.16 h, and 236.52 ± 2.66 h. The larval body length of both species showed a cubic curve relationship with development time. Based on the morphological characteristics, the intra-puparial period of both species were divided into 12 substages. As the temperature increased, the time required for both species to reach each substage decreased significantly. The present study enriches the developmental information of the two Phoridae species and provides a reference basis for using these two phorid flies to estimate the post-burial interval (PBI) of corpses in China. Full article

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

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