Insects

14 pages, 14779 KB

Open AccessArticle

Decoding Biodiversity in Baiyangdian Lake: A DNA Barcode Reference Library for Aquatic Insects

by Ya-Jun Qiao, Ze-Peng Wang, Meng-Yu Lv, Pei-Dong Su, Tong Wu, Hai-Feng Xu, Yu-Fan Li, Xiao-Long Lin and Chun-Hui Zhang

Insects 2026, 17(1), 60; https://doi.org/10.3390/insects17010060 (registering DOI) - 1 Jan 2026

Abstract

Freshwater ecosystems are among the most vulnerable habitats worldwide, and reliable biodiversity assessment is essential for their conservation. Baiyangdian Lake, the largest freshwater lake in northern China, has undergone severe ecological degradation but is now experiencing recovery through restoration efforts. To provide a [...] Read more.

Freshwater ecosystems are among the most vulnerable habitats worldwide, and reliable biodiversity assessment is essential for their conservation. Baiyangdian Lake, the largest freshwater lake in northern China, has undergone severe ecological degradation but is now experiencing recovery through restoration efforts. To provide a molecular basis for monitoring biodiversity, we constructed a COI DNA barcode reference library of aquatic insects from Baiyangdian Lake. From January 2023 to May 2025, systematic sampling across representative habitats yielded 315 high-quality sequences covering 104 species, 74 genera, and 33 families within eight insect orders. Diptera, particularly Chironomidae, showed the highest diversity, followed by Odonata. Phylogenetic analysis using maximum likelihood resolved all orders and families as well-supported monophyletic groups, demonstrating strong congruence with morphological taxonomy. Genetic distance analysis revealed a pronounced barcode gap, with mean intraspecific divergence of 0.46% and nearest-neighbor divergence exceeding 15%, confirming the discriminatory power of COI for species identification. Accumulation curves indicated that genus-level diversity is largely captured, while species-level diversity, especially among Diptera, remains incompletely revealed. This study provides the first comprehensive DNA barcode reference library for Baiyangdian aquatic insects, supporting ecological restoration evaluation, eDNA applications, and regional biodiversity conservation strategies. Full article

(This article belongs to the Special Issue Aquatic Insects Biodiversity and eDNA Monitoring)

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16 pages, 5863 KB

Open AccessArticle

Transcriptomic Analysis of the Cold Resistance Mechanisms During Overwintering in Apis mellifera

by Xiaoyin Deng, Yali Du, Jiaxu Wu, Jinming He, Haibin Jiang, Yuling Liu, Qingsheng Niu and Kai Xu

Insects 2026, 17(1), 59; https://doi.org/10.3390/insects17010059 (registering DOI) - 1 Jan 2026

Abstract

Safe overwintering is a challenging issue in rearing management that is inevitably faced by beekeepers in high-latitude regions. Under the combined influence of multiple factors, the overwintering loss rate of Western honey bees has risen continuously, and investigating the molecular mechanisms related to [...] Read more.

Safe overwintering is a challenging issue in rearing management that is inevitably faced by beekeepers in high-latitude regions. Under the combined influence of multiple factors, the overwintering loss rate of Western honey bees has risen continuously, and investigating the molecular mechanisms related to safe overwintering has become key. The Hunchun bee, an Apis mellifera ecotype in Jilin Province, China, exhibits strong overwintering ability during an overwintering period of more than five months. To investigate the molecular mechanisms of its cold resistance, we conducted a comparative transcriptomic analysis between the summer breeding period (July) and different overwintering intervals (November, December, January, and February), and then systematically identified key genes and signaling pathways related to cold resistance. The results showed that the highest number of differentially expressed genes (DEGs) was found between December and July. Compared with July, the upregulated genes in Hunchun bee in December were significantly enriched in several pathways, such as ion transport and neuroactive ligand–receptor interactions, and the downregulated genes were significantly enriched in pathways related to fatty acid metabolism, glutathione metabolism, and the peroxisome. Notably, a total of 378 shared DEGs were obtained from the four comparison groups, and several candidate cold-resistant gene families, such as AFPs, HSPs, C₂H₂-ZFPs, STKs, and LRRCs, were identified among the shared DEGs of the winter season. Additionally, 749 shared DEGs related to protein modification and metabolic process regulation were identified between the four successive overwintering intervals. Four shared genes, including sensory neuron membrane protein 1 (SNMP1), were revealed by pairwise comparison of the four intervals. The above results collectively indicate that the Hunchun bee attenuates winter-induced stress responses during the overwintering process by maintaining osmotic pressure balance, reducing fatty acid metabolism, increasing antioxidant capacity, and synthesizing cold-resistant macromolecular proteins. It was also found that chemical signal perception may serve a role in maintaining the stability of the overwintering bee colony. The key genes and pathways related to cold resistance identified in this study not only provide a basis for explaining the overwintering molecular mechanism for Apis mellifera of Hunchun bee but also offer key data to improve overwintering management strategies for Western honey bees. Full article

(This article belongs to the Special Issue Insect Transcriptomics)

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13 pages, 3704 KB

Open AccessArticle

Seasonal Dynamics and Nest Characterization of Vespa orientalis (Hymenoptera: Vespidae) in Apiaries: Insights from Bait Trap Capture Efficiency

by Sabreen G. El-Gohary, Abd El-Aziz M. A. Mohsen, Mohammed A. I. Youssif, Lamya Ahmed Alkeridis, Laila A. Al-Shuraym, Samy Sayed, Mustafa Shukry and Sherin M. M. Y. Helaly

Insects 2026, 17(1), 58; https://doi.org/10.3390/insects17010058 (registering DOI) - 1 Jan 2026

Abstract

This study investigated the population dynamics of Vespa orientalis L. (Hymenoptera: Vespidae) across two consecutive seasons (2023–2024) in selected apiaries, with a focus on nest composition (eggs, larvae, and pupae) and the effectiveness of various bait traps for capturing the species. Monthly monitoring [...] Read more.

This study investigated the population dynamics of Vespa orientalis L. (Hymenoptera: Vespidae) across two consecutive seasons (2023–2024) in selected apiaries, with a focus on nest composition (eggs, larvae, and pupae) and the effectiveness of various bait traps for capturing the species. Monthly monitoring revealed the highest population peaks in October and the lowest in December. Notable inter-seasonal variations in population density were observed across the studied sites. The average number of individuals per nest varied between seasons, reflecting fluctuations in colony development and environmental factors. In 2023, the mean counts of cells, eggs, larvae, and pupae per nest were 30.14, 18.77, 13.33, and 20.88, respectively, while in 2024, they were 10.55, 14.81, 18.02, and 30.43. Among the tested attractants, grape juice proved the most effective, capturing an average of 511.67 hornets, followed by black honey (422.33 hornets), whereas the capturing trap caught only 5 hornets. These findings provide insights into the seasonal activity and reproductive status of V. orientalis and support the development of environmentally friendly capture strategies. Full article

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

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11 pages, 757 KB

Open AccessArticle

Validation of Stable Reference Genes for RT-qPCR Normalization in Oxycetonia jucunda (Coleoptera: Scarabaeidae)

by Shi-Hang Zhao, Yang Yue, Rui-Tao Yu, Qi Gao, Jia-Qiang Zhao, Sheng-Ping Zhang, Nan Zhou and Guo-Liang Xu

Insects 2026, 17(1), 57; https://doi.org/10.3390/insects17010057 (registering DOI) - 1 Jan 2026

Abstract

The polyphagous pest Oxycetonia jucunda Faldermann can cause substantial damage to a range of economically important crops, with the adult beetles feeding directly on floral tissues and young leaves. RT-qPCR is widely used to analyze gene expression, for which the selection of stable [...] Read more.

The polyphagous pest Oxycetonia jucunda Faldermann can cause substantial damage to a range of economically important crops, with the adult beetles feeding directly on floral tissues and young leaves. RT-qPCR is widely used to analyze gene expression, for which the selection of stable reference genes is essential for enabling an accurate normalization of expression. However, no systematic evaluations of suitable reference genes for RT-qPCR analysis using different tissues of O. jucunda have been conducted. To assess their applicability as reliable normalization controls, we used five computational methods to examine the stability of seven potential reference genes (GAPDH, EF1α, RPS3, RPS18, RPL18, RPS31, and UBC5A) across six adult tissues, with three biological replicates per tissue. The findings revealed RPS3 and RPS31 to be the most stably expressed. This pair of reference genes was further validated by normalizing the expression of the odorant-binding protein 3 (OBP3) target gene. Our findings will provide important foundational data for the accurate analysis of functional gene expression in O. jucunda. Full article

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

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10 pages, 1305 KB

Open AccessCommunication

Modeling Pine Caterpillar, Dendrolimus spectabilis (Lepidoptera: Lasiocampidae), Population Dynamics with a Stage-Structured Matrix Model Based on Field Observations

by Young-Kyu Park, Youngwoo Nam and Won Il Choi

Insects 2026, 17(1), 56; https://doi.org/10.3390/insects17010056 (registering DOI) - 1 Jan 2026

Abstract

Population models offer insights into both theoretical and practical aspects of insect population dynamics. Among the models, stage-structured matrix models are used to describe the population dynamics of insects because the development of insects is by nature stage-structured. Field populations of the pine [...] Read more.

Population models offer insights into both theoretical and practical aspects of insect population dynamics. Among the models, stage-structured matrix models are used to describe the population dynamics of insects because the development of insects is by nature stage-structured. Field populations of the pine caterpillar, Dendrolimus spectabilis (Lepidoptera: Lasiocampidae) were monitored in a pine stand located in Dorak-ri, Cheongsan-myeon, Wando-gun, Jeollanam-do, from May 1998 to March 1999, and the pest density was measured as the number of larvae, pupae, or eggs at one-month intervals, excluding the winter season. Life tables and matrix models were constructed based on field observations, and the most vulnerable life stage was identified through sensitivity analysis. The density of the pine caterpillar (number per 1000 cm² branch) was 7.9 on 8 May 1998, and subsequently decreased to 0.5 on 14 March 1999, showing a decreasing trend of caterpillar density. The population growth rate was 0.74, a decreasing trend. The most vulnerable stages were (1) the larvae immediately after hatching and (2) again during overwintering, probably due to indirect mortality caused by humid conditions and activities of natural enemies during winter. Given the significant damage caused by mature larvae in the spring and that the density of the caterpillar after overwintering typically remains stable, forest management requires that the pest density be monitored soon after overwintering to allow decisions about control measures to be taken. Our results showed that a matrix model is useful to describe the population dynamics of the pine caterpillar and to construct suitable management strategies. Full article

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

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22 pages, 4733 KB

Open AccessArticle

Integrative Analysis of Antennal Morphology and Olfactory Receptor Gene Expression Across the Three Castes of Bombus terrestris (Hymenoptera: Apidae)

by Yu Zhang, Lina Guo and Yuan Guo

Insects 2026, 17(1), 55; https://doi.org/10.3390/insects17010055 (registering DOI) - 1 Jan 2026

Abstract

To systematically investigate how the olfactory system of Bombus terrestris adapts to its social division of labor and reproductive strategies, this study integrated the micromorphology of antennal sensilla and the expression profiles of olfactory receptor (OR) genes from the heads of its three [...] Read more.

To systematically investigate how the olfactory system of Bombus terrestris adapts to its social division of labor and reproductive strategies, this study integrated the micromorphology of antennal sensilla and the expression profiles of olfactory receptor (OR) genes from the heads of its three castes (workers, drones, and queens) for a multi-level analysis. Scanning electron microscopy (SEM) revealed that drones possess significantly longer chaetic sensilla (Sch), sensilla trichodea (Str A/B), and sensilla basiconica (Sba A), as well as larger-diameter sensilla coeloconica (Sco) compared to workers and queens, indicating structural and functional specialization for sensitive detection of single key signals (e.g., queen pheromones). In contrast, workers and queens exhibited a more complete composition of sensilla types and a higher sensilla distribution density, suggesting the construction of a perceptual system capable of processing multiple chemical signals simultaneously. RNA-seq combined with qRT-PCR confirmed the significant upregulation of seven OR genes (e.g., BterOR3, BterOR4) in drones, while workers showed upregulation of BterOR3/5/7 accompanied by enrichment of P450 detoxification pathways. Phylogenetic analysis suggested that BterOR5 serves as a conserved co-receptor, and some OR genes may originate from recent duplication events. In summary, distinct differences were observed in the morphological structure and molecular expression of the olfactory system among B. terrestris castes. Drones exhibited structural and gene expression features consistent with specialization in queen pheromone detection, while workers and queens demonstrated sensilla diversity and olfactory receptor expression patterns indicative of a broader response capacity to diverse chemical signals. These findings support the view that the olfactory system has undergone multi-level adaptive evolution driven by social division of labor and reproductive roles. Full article

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

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10 pages, 12175 KB

Open AccessArticle

Deciphering Morphological Variability: Addressing Taxonomic Ambiguities in Contemporary Species Delimitation (Hymenoptera, Figitidae)

by Mar Ferrer-Suay, George E. Heimpel, Ehsan Rakhshani and Jesús Selfa

Insects 2026, 17(1), 54; https://doi.org/10.3390/insects17010054 (registering DOI) - 1 Jan 2026

Abstract

Species delimitation in Charipinae hyperparasitoids (Hymenoptera: Figitidae) is notoriously difficult due to their minute size and limited morphological variability. Traditional diagnostic characters sometimes show intraspecific variation, raising concerns about their reliability. Here, we applied an integrative taxonomic framework to evaluate species boundaries among [...] Read more.

Species delimitation in Charipinae hyperparasitoids (Hymenoptera: Figitidae) is notoriously difficult due to their minute size and limited morphological variability. Traditional diagnostic characters sometimes show intraspecific variation, raising concerns about their reliability. Here, we applied an integrative taxonomic framework to evaluate species boundaries among six species of Alloxysta Förster and four species of Phaenoglyphis Förster. We combined a morphological dataset of 53 characters with data from three molecular markers (COI, ITS2, and 16S rRNA) and reconstructed phylogenies under maximum-likelihood criteria. Phylogenies consistently recovered morphologically defined taxa as well-supported clades, confirming the overall reliability of traditional characters (pronotal and propodeal carinae, radial cell shape, and flagellomere proportions). On the other hand, molecular evidence refined certain species limits and highlighted cases of potential cryptic variation. Our results demonstrate that morphology still provides a strong baseline for Charipinae taxonomy, but integration with molecular data yields more robust and stable classifications. This study underscores the value of multi-locus approaches for resolving taxonomic ambiguities and provides a framework for future ecological and evolutionary research on these hyperparasitoid wasps. Full article

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

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14 pages, 4811 KB

Open AccessArticle

The Honey Bee Body Surface as a Microbial Hub: Connectivity Shaped by Monoculture vs. Polyculture Farming

by Baobei Guo, Xueyan Yi, Qihang Sun, Ke Sun, Lina Guo and Yuan Guo

Insects 2026, 17(1), 53; https://doi.org/10.3390/insects17010053 (registering DOI) - 1 Jan 2026

Abstract

Honey bees, as vital pollinators and essential contributors to terrestrial ecosystems, play a critical role in maintaining biodiversity and ecological stability. Beyond their role as pollinators, honey bees are increasingly recognized as bioindicators of environmental health, with their microbiomes reflecting habitat quality, agricultural [...] Read more.

Honey bees, as vital pollinators and essential contributors to terrestrial ecosystems, play a critical role in maintaining biodiversity and ecological stability. Beyond their role as pollinators, honey bees are increasingly recognized as bioindicators of environmental health, with their microbiomes reflecting habitat quality, agricultural practices, and broader ecological conditions. This study examines the impact of monoculture and polyculture systems on bee-associated microbiomes, focusing on microbial diversity, composition, and functional roles. Microbial communities from floral surfaces, pollen, nectar, foraging bees, hive matrices, and bioaerosols were analyzed across three agricultural plots: a rape monoculture, a pear monoculture, and a polyculture plot. Using 16S rRNA amplicon sequencing, network co-occurrence analysis, and microbial source tracking, the findings reveal that plant species and cultivation methods significantly shape microbial dynamics (Adonis = 0.67 ***). Floral microbiomes exhibit host specificity (Adonis = 0.73 ***), while the honey bee body surface functions as a microbial hub linking environmental, floral, and hive microbial networks (average degree pear: 21.86; rape: 21.96). The polyculture system improves microbial diversity due to the diversity of nectar plants, enhancing ecosystem connectivity and potentially benefiting honey bee health. These results highlight the ecological importance of optimizing agricultural practices to preserve microbial diversity, enhance honey bee health, and maintain ecological stability. Full article

(This article belongs to the Special Issue Current Advances in Pollinator Insects)

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14 pages, 1115 KB

Open AccessCommunication

Characterization of the Bacteriome of Culicoides reevesi from Chihuahua, Northern Mexico: Symbiotic and Pathogenic Associations

by Rodolfo González-Peña, David Orlando Hidalgo-Martínez, Stephanie V. Laredo-Tiscareño, Herón Huerta, Erick de Jesús de Luna-Santillana, Jaime R. Adame-Gallegos, Carlos A. Rodríguez-Alarcón, Ezequiel Rubio-Tabares, Julián E. García-Rejón, Zilia Y. Muñoz-Ramírez, Chandra Tangudu and Javier A. Garza-Hernández

Insects 2026, 17(1), 52; https://doi.org/10.3390/insects17010052 (registering DOI) - 1 Jan 2026

Abstract

Culicoides biting midges are vectors of veterinary and zoonotic pathogens, yet the bacteriome of several species remains unexplored. Culicoides reevesi, a poorly studied species in northern Mexico, represents an opportunity to investigate microbial associations that may influence vector biology. Adults of C. [...] Read more.

Culicoides biting midges are vectors of veterinary and zoonotic pathogens, yet the bacteriome of several species remains unexplored. Culicoides reevesi, a poorly studied species in northern Mexico, represents an opportunity to investigate microbial associations that may influence vector biology. Adults of C. reevesi were analyzed using 16S rRNA amplicon sequencing, followed by functional prediction with PICRUSt2. Heatmaps and pathway summaries were generated to highlight dominant taxa and functions. The bacteriome was dominated by Pseudomonadota, followed by Actinomycetota, Bacillota, and Bacteroidota. Symbiotic taxa such as Asaia and Cardinium were identified alongside potentially pathogenic bacteria, including Escherichia coli, Mycobacterium avium, Vibrio parahaemolyticus, and Enterococcus faecalis. Functional predictions indicated metabolic versatility, with abundant pathways related to aerobic respiration, the TCA cycle, amino acid biosynthesis, and quorum sensing. Despite all samples being collected from the same site and date, apparent differences in bacterial composition were observed across pools, suggesting microhabitat or host-related variability. This study provides the first taxonomic and functional baseline of the C. reevesi bacteriome. The detection of both symbiotic and pathogenic bacteria highlights the dual ecological role of the microbiome in host fitness and pathogen transmission potential. In conclusion, we suggest that these microbial associations influence vector physiology and competence, providing a basis for future microbiome-based control strategies. These findings emphasize the importance of integrating microbiome analyses into entomological surveillance and vector control strategies in endemic regions. Full article

(This article belongs to the Topic Diversity of Insect-Associated Microorganisms)

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14 pages, 904 KB

Open AccessArticle

A Compound Fungicide Impairs Cognitive Performance in Honey Bees (Apis mellifera)

by Xufeng Zhang, Qian Cao, Qihang Sun, Yuting Tian, Yinyin Du and Yuan Guo

Insects 2026, 17(1), 51; https://doi.org/10.3390/insects17010051 - 30 Dec 2025

Abstract

Fungicides play a critical role in crop protection, yet their potential threats to pollinator remain a concern. This study investigated the sublethal effects of a commercial fungicide, Chunmanchun^® (a suspension-emulsion of 7% propiconazole and 28% carbendazim), on cognitive functions of the honey [...] Read more.

Fungicides play a critical role in crop protection, yet their potential threats to pollinator remain a concern. This study investigated the sublethal effects of a commercial fungicide, Chunmanchun^® (a suspension-emulsion of 7% propiconazole and 28% carbendazim), on cognitive functions of the honey bee (Apis mellifera). Using the proboscis extension reflex (PER) assay, we evaluated sucrose sensitivity and olfactory learning and memory in workers exposed to the recommended field concentration (PC), along with sublethal (LD₁₀) and semi-lethal (LD₅₀) concentrations. Fungicide exposure significantly reduced sucrose sensitivity across all concentrations tested (0.1%, 1%, and 3%), with the strongest reductions occurring at the LD₁₀ and LD₅₀ levels. While olfactory associative learning was not significantly impaired, memory retention was adversely affected. Bees in the LD₅₀ group showed significantly reduced PER rates at both1 h and 6 h post-training, and LD₁₀ and LD₅₀ groups exhibited significant memory deficits by 1 h and 6 h relative to the control. These results demonstrate that Chunmanchun^® impairs both sucrose responsiveness and olfactory memory in honey bees, which may impair foraging efficiency and ultimately affect colony performance. This study highlights a potential ecological risk posed by this fungicide to pollinators in agricultural environments. Full article

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

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12 pages, 1746 KB

Open AccessArticle

The First Record of Whitefly (Hemiptera, Sternorrhyncha, Aleyrodidae) from Bitterfeld Amber

by Jowita Drohojowska, Anita Gorzelańczyk, Natalia Tomanek, Małgorzata Kalandyk-Kołodziejczyk and Jacek Szwedo

Insects 2026, 17(1), 50; https://doi.org/10.3390/insects17010050 - 30 Dec 2025

Abstract

A male specimen of whitefly Pudrica christianottoi Drohojowska et Szwedo, 2024, of subfamily Aleyrodinae, previously known from the sole female specimen from Lower Lusatia succinite, is here described, based on an inclusion from Bitterfeld amber. This fossil is contributing new data to our [...] Read more.

A male specimen of whitefly Pudrica christianottoi Drohojowska et Szwedo, 2024, of subfamily Aleyrodinae, previously known from the sole female specimen from Lower Lusatia succinite, is here described, based on an inclusion from Bitterfeld amber. This fossil is contributing new data to our understanding of morphological disparity, sexual dimorphism, taxonomic diversity and palaeobiogeographic distribution of the whiteflies in the Eocene fossil resins. It is also a contribution to the ongoing discussions on age, similarities, dissimilarities and taphonomic differences among Eocene resins of Europe collectively known as ‘Baltic amber’. Full article

(This article belongs to the Special Issue Fossil Insects: Diversity and Evolutionary History)

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18 pages, 3317 KB

Open AccessArticle

Bumblebee Diversity in Different Habitat Types and Along an Altitudinal Gradient at a Forest–Grassland Ecotone in the East Range of the Qinghai–Tibet Plateau

by Xunlu Xu, Lei Bai, Zhaolong Wang, Jianping He, Yalin Zhang and Xiushan Li

Insects 2026, 17(1), 49; https://doi.org/10.3390/insects17010049 - 30 Dec 2025

Abstract

Bumblebees are the most important pollinators in alpine areas. Their survival is vulnerable to anthropogenic disturbance. To comprehend the variation in bumblebee diversity in different habitat types and altitudinal gradient, this study carried out transect counting in three distinct habitat types and altitudinal [...] Read more.

Bumblebees are the most important pollinators in alpine areas. Their survival is vulnerable to anthropogenic disturbance. To comprehend the variation in bumblebee diversity in different habitat types and altitudinal gradient, this study carried out transect counting in three distinct habitat types and altitudinal gradient in the source area of the Bailong River between June and September from 2021 to 2022. The result indicates (1) high species richness in bumblebees, as 27 species and 1106 individuals from 9 subgenera were collected. It indicates that the Forest–Grassland ecotone has rich bumblebee diversity. Edge effective and suitable habitats bred rich bumblebees. (2) Species richness and abundance differed between three habitat types: alpine meadows had the highest; shrubs on the forest edge had the second highest; and grasslands had the lowest. (3) The distribution pattern in the altitude of bumblebees shows two peaks. The species richness and abundance of bumblebee are highest in the ranges of 3500–3700 m and 2900–3100 m, while 3100–3500 m is lower than the other altitude ranges, presumably because this range is just a large grassland with overgrazing. (4) The results of redundancy analysis indicate that environmental factors significantly affect the diversity of bumblebees. (5) The conservation measures should mainly focus on alpine meadows, as they are the most important habitat of the bumblebee. Reducing overgrazing in large-scale grasslands is beneficial to bumblebees as well as wildflower plants. Full article

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

17 pages, 3199 KB

Open AccessArticle

Effects of Different Levels of Drought Stress in Ficus Plants on the Life History and Population Growth of Perina nuda (Lepidoptera: Lymantriidae): An Age-Stage, Two-Sex Life Table Analysis

by Changqi Chen, Yunfang Guan, Yan Wang, Ying Zhang, Zhu Liu, Yana Zhou, Zongbo Li and Yuan Zhang

Insects 2026, 17(1), 48; https://doi.org/10.3390/insects17010048 - 30 Dec 2025

Abstract

Under the background of global climate change, frequent drought events have significantly impacted plant–insect interaction. This study focuses on Ficus microcarpa, an important landscaping and urban greening tree species in tropical and subtropical regions, and its primary herbivorous pest, Perina nuda, [...] Read more.

Under the background of global climate change, frequent drought events have significantly impacted plant–insect interaction. This study focuses on Ficus microcarpa, an important landscaping and urban greening tree species in tropical and subtropical regions, and its primary herbivorous pest, Perina nuda, by applying the age-stage, two-sex life table theory to systematically evaluate the effects on the life history traits and population dynamics of P. nuda reared on F. microcarpa subjected to different levels of drought stress. The results demonstrated that reared on drought-stressed F. microcarpa significantly altered multiple life history traits of P. nuda. All drought treatments significantly shortened the larval development period. Under both light and severe drought conditions, adult lifespan was prolonged, the total pre-oviposition period was reduced, fecundity per female increased, and generation time (T) was shortened. However, significant increases in pupal weight, intrinsic rate of increase (r), and finite rate of increase (λ) were observed only under light drought stress. The population prediction results indicate that both light and severe drought stress lead to obviously higher population growth rates and larger population sizes at 200 days compared to the control group. These findings suggest that the population fitness of P. nuda is enhanced under light and severe drought stress, potentially increasing the probability of pest outbreaks. This study provides an important theoretical basis and practical advice on forecasting population dynamics and implementing integrated management strategies for P. nuda in the context of climate change. Full article

(This article belongs to the Special Issue Effects of Environment and Food Stress on Insect Population)

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21 pages, 12116 KB

Open AccessArticle

Morphological Ontogeny and Life Cycle of Laboratory-Maintained Eremobelba eharai (Acari: Oribatida: Eremobelbidae)

by Chang Chu, Yu Chen and Jun Chen

Insects 2026, 17(1), 47; https://doi.org/10.3390/insects17010047 - 30 Dec 2025

Abstract

This study presents the first successful laboratory rearing of Eremobelba eharai, with the establishment of a sustainable multigenerational breeding system. We document for the first time its complete morphological ontogeny across all developmental stages (from larva to adult) and characterize its life [...] Read more.

This study presents the first successful laboratory rearing of Eremobelba eharai, with the establishment of a sustainable multigenerational breeding system. We document for the first time its complete morphological ontogeny across all developmental stages (from larva to adult) and characterize its life cycle. We supplement the original adult description with detailed morphological characterization and illustrations of the gnathosomatic structures, including the subcapitulum, palps, and chelicerae. Scanning electron microscopy showed that its surface is covered with a granular cerotegument. Under isolated rearing conditions, this species can complete the entire egg-to-egg developmental cycle. In addition, preliminary behavioral observations during rearing revealed preferences for dark environments, characteristic leg-shaking movements, and gregarious oviposition on active dry yeast particles, with no evidence of cannibalism. Full article

(This article belongs to the Section Other Arthropods and General Topics)

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9 pages, 372 KB

Open AccessArticle

The Lacewings Micromus angulatus and Chrysoperla carnea as Predators of the Rhododendron Aphid, Illinoia lambersi, Under Different Temperature Regimes

by Marie Froyen, Robin Beckx, Ellen Peeters, Wan-Yi Liao, Joachim Audenaert, Ruth Verhoeven, Alberto Pozzebon, Bruno Gobin and Patrick De Clercq

Insects 2026, 17(1), 46; https://doi.org/10.3390/insects17010046 - 30 Dec 2025

Abstract

Illinoia lambersi is a key aphid pest in Rhododendron cultivation in northwestern Europe, where control measures still heavily rely on chemical insecticides. The present laboratory study assessed the predatory potential of the brown lacewing Micromus angulatus on a mix of late instars and [...] Read more.

Illinoia lambersi is a key aphid pest in Rhododendron cultivation in northwestern Europe, where control measures still heavily rely on chemical insecticides. The present laboratory study assessed the predatory potential of the brown lacewing Micromus angulatus on a mix of late instars and adults of I. lambersi across three temperatures (15, 20, and 25 °C) and compared its performance with that of the commonly used green lacewing Chrysoperla carnea sensu lato. Predation rates were measured for third-instar larvae and adults of M. angulatus and for second- and third-instar larvae of C. carnea. Third instars of M. angulatus were highly effective, killing 30–52 aphids per day, with predation significantly increasing at 25 °C. At 15 °C, M. angulatus third instars performed similarly to C. carnea third instars; at 20 °C, C. carnea exhibited higher predation. In all cases, M. angulatus third instars outperformed C. carnea second instars. Female M. angulatus adults maintained steady predation rates (≈30–40 aphids per day) across temperatures, whereas males were less voracious. These findings highlight the potential of M. angulatus as a predator in both its larval and adult stages for integration into IPM programs targeting in particular early-season I. lambersi outbreaks under cool spring conditions. Further field studies are needed to validate laboratory findings and assess the performance of the predator across different Rhododendron cultivars. Full article

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

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14 pages, 8611 KB

Open AccessArticle

The Courtship Behavior and the Ultrastructure of Sex Pheromone Glands in the Hind Tibiae of Male Ghost Moth Endoclita davidi (Lepidoptera: Hepialidae)

by Xingrui Huang, Shan Chen, Xing Li, Zihao Zhou and Qiong Zhou

Insects 2026, 17(1), 45; https://doi.org/10.3390/insects17010045 - 30 Dec 2025

Abstract

The courtship behavior of moths is closely related to the biosynthesis and release of sex pheromones. To understand the mechanisms of the reproductive behavior of the ghost moth Endoclita davidi, a host insect of Cordyceps xuefeng (Ophiocordyceps xuefengensis), this study [...] Read more.

The courtship behavior of moths is closely related to the biosynthesis and release of sex pheromones. To understand the mechanisms of the reproductive behavior of the ghost moth Endoclita davidi, a host insect of Cordyceps xuefeng (Ophiocordyceps xuefengensis), this study examined the courtship behavior and the ultrastructure of the sex pheromone gland of E. davidi. Infrared photography was used to analyze the courtship behavior, while SEM, paraffin tissue sectioning, and TEM were employed to examine the sex pheromone glands on the hind tibia. The courtship behavior of E. davidi occurs during the scotophase, during which males vibrate their wings and unfold the hairpencils located on the hind tibiae to lure the female moths. The hairpencil’s surface features regular longitudinal ridges interspersed with multiple circular pits. Multiple small holes were evident on the slightly enlarged areas close to the ends of the hairpencils. These small holes, formed at the base of the circular pits, connect to the internal glandular duct within the hairpencil, which links to the tibia glandular canal. The epidermal layer of the hind tibiae contains numerous glandular canals and dense microvilli. The glandular cells, specialized from dermal cells, contain numerous mitochondria, rough endoplasmic reticulum, clear vesicles of varying sizes, and round lipid droplets. The sex pheromone glands of male E. davidi release pheromones through the hairpencils in the hind tibia. The courtship behavior and ultrastructure of the sex pheromone gland of the male E. davidi provide a basis for further understanding pheromone release and communication mechanisms. Full article

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

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13 pages, 19345 KB

Open AccessArticle

Coalescent Simulations and Field Experiments Support Natural Selection as the Driving Force Maintaining Color Differences Between Adjacent Populations of Ceroglossus chilensis (Coleoptera: Carabidae)

by Benjamín Arenas-Gutierrez, Antonio Rivera-Hutinel and Carlos P. Muñoz-Ramírez

Insects 2026, 17(1), 44; https://doi.org/10.3390/insects17010044 - 30 Dec 2025

Abstract

Determining the drivers of phenotypic evolution and their role on shaping regional phenotypic diversity is a fundamental aspect of mimicry research. Beetles of the genus Ceroglossus are well known for their rampant color diversity, and species have been shown to exhibit convergence in [...] Read more.

Determining the drivers of phenotypic evolution and their role on shaping regional phenotypic diversity is a fundamental aspect of mimicry research. Beetles of the genus Ceroglossus are well known for their rampant color diversity, and species have been shown to exhibit convergence in elytral coloration when in sympatry. Despite solid phylogenetic evidence showing that color convergence is not the result of shared ancestry, more direct evidence of the role of selection on color evolution is lacking. In this study, we used two different, but complementary approaches to test whether selection plays a role in color divergence and whether predators are responsible for its maintenance. We first used molecular data to assess gene flow. Subsequently, we used the sequence data to conduct coalescent simulations and generate expectations for color fixation under the hypothesis of genetic drift. Second, we conducted field experiments to test whether predators exhibited different preferences on mimetic versus non-mimetic phenotypes. Results from the coalescent simulations showed that color fixation exhibited strong deviations from the genetic drift expectation, implying that selection must be responsible for color divergence. Field experiments showed that translocated beetles (into areas where they were not mimics) suffered higher rates of attacks than those beetles that mimicked the locally abundant phenotypes. Thus, our study supports the hypothesis of selection as a driving force of color evolution in Ceroglossus beetles and provides the context that explains and supports previous claims of Müllerian mimicry. Full article

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

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26 pages, 7201 KB

Open AccessArticle

Niche Differentiation and Predicted Functions of Microbiomes in a Tri-Trophic Willow–Gall (Euura viminalis)–Parasitoid Wasp System

by Yuhao Nie, Gaopeng Yu and Hongying Hu

Insects 2026, 17(1), 43; https://doi.org/10.3390/insects17010043 - 29 Dec 2025

Abstract

Chalcidoids (Hymenoptera: Chalcidoidea), the most important natural enemies of parasitoids, serve as a pivotal factor in the regulation and management of pest populations. Microbiotas mediate interactions among plants, herbivores, and natural enemies and shape host immunity, parasitoid development, and gall formation; however, the [...] Read more.

Chalcidoids (Hymenoptera: Chalcidoidea), the most important natural enemies of parasitoids, serve as a pivotal factor in the regulation and management of pest populations. Microbiotas mediate interactions among plants, herbivores, and natural enemies and shape host immunity, parasitoid development, and gall formation; however, the niche-specific diversity and functions of tritrophic parasitoid–host–gall systems remain unclear. Focusing on leaf galls induced on twisted willow (Salix matsudana f. tortuosa) by the willow-galling sawfly Euura viminalis and on two chalcidoids, Eurytoma aethiops and Aprostocetus sp., we profiled bacterial and fungal microbiomes across plant surfaces, gall lumen, host larval tissues, and parasitoids using HTAS. Fungal diversity peaked on parasitoids but was depleted in the gall lumen and host tissues; bacterial richness showed the opposite trend, peaking in the gall lumen and decreasing on parasitoids. In networks contrasted by kingdom, fungi showed positive interface-hub connectivity (Cladosporium, Alternaria), whereas bacteria showed negative hub-mediated associations (Pseudomonas, Acinetobacter), indicating habitat-specific replacements: exposed niches favored transport, two-component, secretion–motility and energy functions, whereas the gall lumen reduced transport/motility but selectively retained N/S metabolism; and in host tissues, information processing and nitrogen respiration were highlighted. These results inform microbiome-guided parasitoid biocontrol. Full article

(This article belongs to the Topic Diversity of Insect-Associated Microorganisms)

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16 pages, 5067 KB

Open AccessArticle

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

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

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

Abstract

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

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

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

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