Journal Description
Insects
Insects
is an international, peer-reviewed, open access journal on entomology published monthly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), PubMed, PMC, PubAg, and other databases.
- Journal Rank: JCR - Q1 (Entomology) / CiteScore - Q1 (Insect Science)
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 17 days after submission; acceptance to publication is undertaken in 2.8 days (median values for papers published in this journal in the first half of 2024).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
Impact Factor:
2.7 (2023);
5-Year Impact Factor:
2.9 (2023)
Latest Articles
Field Exploration for Colony Selection: Evaluating Hygienic Behavior in Apis cerana indica Colonies
Insects 2024, 15(8), 598; https://doi.org/10.3390/insects15080598 - 6 Aug 2024
Abstract
Hygienic behavior (HB) emerges as a pivotal trait, impacting colony resistance to diseases. This study aimed to understand the behavioral traits of Apis cerana indica colonies, with a focus on HB and other key characteristics crucial for colony health, and to screen and
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Hygienic behavior (HB) emerges as a pivotal trait, impacting colony resistance to diseases. This study aimed to understand the behavioral traits of Apis cerana indica colonies, with a focus on HB and other key characteristics crucial for colony health, and to screen and identify colonies with superior hygienic behavior and better performance to combat prevailing diseases and pests. This research spans a comprehensive field analysis with different seasons and locations, encompassing the distinct environmental and management factors that influence honey bee behavior. The inclusion of A. cerana indica colonies from various locations provides a novel perspective, offering valuable insights regarding the hygienic behavior of A. cerana indica. Several statistical analyses, including descriptive statistics, principal component analysis (PCA), and Aligned Rank Transformation-Analysis of Variance (ART-ANOVA) for repeated measures, shed light on the distribution of hive metrics, emphasizing the significance of considering seasonality and location-specific factors. PCA highlights unique characteristics in Tirupur and Coimbatore colonies, while correlation analyses uncover relationships among HB, honey, pollen, brood area, and adult population. Moreover, the study’s nuanced findings gave the status of hygienic behavior of A. cerana indica colonies and identified colonies with better colony performance, which will be useful for future breeding programs with A. cerana indica.
Full article
(This article belongs to the Special Issue Bee Health and Beehive Management in a Changing World)
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Open AccessArticle
Temperature-Dependent Oviposition Models for Monochamus saltuarius (Coleoptera: Cerambycidae)
by
Hyoseok Lee, Jong-Kook Jung, Youngwoo Nam and Sang-Hyun Koh
Insects 2024, 15(8), 597; https://doi.org/10.3390/insects15080597 - 6 Aug 2024
Abstract
Monochamus saltuarius Gebler is a serious insect pest in Europe and East Asia regions, including Portugal, Spain, China, Japan, and Korea. It transfers the pine wood nematode Bursaphelenchus xylophilus to conifer trees, resulting in pine wilt disease (PWD). As temperature is a key
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Monochamus saltuarius Gebler is a serious insect pest in Europe and East Asia regions, including Portugal, Spain, China, Japan, and Korea. It transfers the pine wood nematode Bursaphelenchus xylophilus to conifer trees, resulting in pine wilt disease (PWD). As temperature is a key factor influencing insect population dynamics, temperature-dependent models describing M. saltuarius oviposition could estimate population growth potential and evaluate outbreak risks. In this study, the longevity and fecundity of M. saltuarius females were measured under constant temperature conditions ranging from 20 to 32 °C, and temperature-dependent models were constructed. The longevity of M. saltuarius females ranged from 83.36 days to 22.92 days, with a total fecundity of 141 eggs and 52.77 eggs at 20 °C and 32 °C, respectively. To describe oviposition, we used a single-phase simulation describing oviposition as a single model and a two-phase simulation describing sexual maturation and oviposition as two separate models. These models effectively described M. saltuarius oviposition (r2 > 0.96) under constant temperature conditions, with the two-phase simulation demonstrating greater accuracy overall. Such models could facilitate assessments of PWD risks. The modeling framework of this study shows potential for predicting threats from various forestry and agricultural pests.
Full article
(This article belongs to the Section Insect Pest and Vector Management)
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Open AccessArticle
Diversity of Ladybird Beetles (Coleoptera: Coccinellidae) in Tenerife and La Gomera (Canary Islands): The Role of Size and Other Island Characteristics
by
Jerzy Romanowski, Piotr Ceryngier, Jaroslav Vĕtrovec, Christian Zmuda and Karol Szawaryn
Insects 2024, 15(8), 596; https://doi.org/10.3390/insects15080596 - 6 Aug 2024
Abstract
This paper provides new data on the ladybird beetles (Coccinellidae) from two islands in the Canary archipelago: Tenerife, the largest island, and La Gomera, the second smallest. As they clearly differ in size but are similar in location and geological age, they are
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This paper provides new data on the ladybird beetles (Coccinellidae) from two islands in the Canary archipelago: Tenerife, the largest island, and La Gomera, the second smallest. As they clearly differ in size but are similar in location and geological age, they are a suitable model for testing the species–area relationship. Our study shows that, in line with this main assumption of the theory of island biogeography, clearly more species occur on a large island (Tenerife) than on a small one (La Gomera). The field surveys documented the occurrence of 35 ladybird species on Tenerife (including 5 not previously reported from this island) and of 20 species on La Gomera (2 species new to the island). Coelopterus sp. collected on Tenerife (a single female that could not be identified to species) is the first record of this genus for the whole Canary Islands. Taking our data and previously published records into account, 47 species of Coccinellidae are known to occur on Tenerife and 26 species on La Gomera. Tenerife has by far the richest ladybird fauna of all the Canary Islands (the next in line, Gran Canaria, has 41 recorded species), but it also has the highest number of non-native ladybird species. All of the ten non-native species recorded in the Canary Islands are found on Tenerife, and for most of them, Tenerife was the island of their first appearance in the archipelago. This island, much more distant from the mainland than the other relatively large islands (Fuerteventura, Lanzarote), appears to be the main recipient of ladybirds immigrating to the Canary Islands. Tenerife can play this role probably because of its great habitat diversity and altitude variation, as well as intensive tourism and trade-related transport.
Full article
(This article belongs to the Special Issue Advances in Understanding of the Ecology and Biodiversity of Coleoptera: Coccinellidae)
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Open AccessArticle
Effects of Bacillus thuringiensis Treatment on Expression of Detoxification Genes in Chlorantraniliprole-Resistant Plutella xylostella
by
Maryam Zolfaghari, Fei Yin, Juan Luis Jurat-Fuentes, Yong Xiao, Zhengke Peng, Jiale Wang, Xiangbing Yang and Zhen-Yu Li
Insects 2024, 15(8), 595; https://doi.org/10.3390/insects15080595 - 5 Aug 2024
Abstract
Detoxification genes are crucial to insect resistance against chemical pesticides, yet their expression may be altered by exposure to biopesticides such as spores and insecticidal proteins of Bacillus thuringiensis (Bt). Increased enzymatic levels of selected detoxification genes, including glutathione S-transferase (GST), cytochrome P450
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Detoxification genes are crucial to insect resistance against chemical pesticides, yet their expression may be altered by exposure to biopesticides such as spores and insecticidal proteins of Bacillus thuringiensis (Bt). Increased enzymatic levels of selected detoxification genes, including glutathione S-transferase (GST), cytochrome P450 (CYP450), and carboxylesterase (CarE), were detected in chlorantraniliprole (CAP)-resistant strains of the diamondback moth (DBM, Plutella xylostella) from China when compared to a reference susceptible strain. These CAP-resistant DBM strains displayed distinct expression patterns of GST 1, CYP6B7, and CarE-6 after treatment with CAP and a Bt pesticide (Bt-G033). In particular, the gene expression analysis demonstrated significant upregulation of the CYP6B7 gene in response to the CAP treatment, while the same gene was downregulated following the Bt-G033 treatment. Downregulation of CYP6B7 using RNAi resulted in increased susceptibility to CAP in resistant DBM strains, suggesting a role of this gene in the resistant phenotype. However, pretreatment with a sublethal dose of Bt-G033 inducing the downregulation of CYP6B7 did not significantly increase CAP potency against the resistant DBM strains. These results identify the DBM genes involved in the metabolic resistance to CAP and demonstrate how their expression is affected by exposure to Bt-G033.
Full article
(This article belongs to the Special Issue How the Detoxification Genes Increase Insect Resistance)
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Open AccessArticle
Evaluation and Validation of Reference Genes for Gene Expression Analysis Using qRT-PCR in the Sugarcane Stem Borer Chilo sacchariphagus (Lepidoptera: Pyralidae)
by
Zhixiong Wang, Xiankun Shang, Jili Wei, Xiaoli Tian, Yi Liu and Guohui Zhang
Insects 2024, 15(8), 594; https://doi.org/10.3390/insects15080594 - 4 Aug 2024
Abstract
Chilo sacchariphagus (Lepidoptera: Pyralidae) is an economically important sugarcane pest. Although numerous studies were conducted on the physiological responses in C. sacchariphagus, little is known regarding the genes regulating these physiological processes. Gene expression analysis by qRT-PCR can offer a significant indication
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Chilo sacchariphagus (Lepidoptera: Pyralidae) is an economically important sugarcane pest. Although numerous studies were conducted on the physiological responses in C. sacchariphagus, little is known regarding the genes regulating these physiological processes. Gene expression analysis by qRT-PCR can offer a significant indication for functional gene studies. To our knowledge, the reference genes of C. sacchariphagus have not been screened or evaluated, which hinders the functional gene study. In the present study, the stability of seven reference genes (β-ACT, GAPDH, BTF3, 28S, RPL7, EF1α, and SDHA) was evaluated in C. sacchariphagus under different experimental conditions, including tissues (antenna, head, thorax, abdomen, leg, and wing), temperatures (4 °C, 25 °C, and 37 °C) and sexes (male and female), through RefFinder, which integrates four algorithms (Normfinder, BestKeeper, ΔCt method, and geNorm). The findings suggested that the combination of β-ACT and RPL7 is ideal to analyze gene expressions in different tissues and at distinct temperatures, and EF1α and SDHA were suitable reference genes for comparing gene expressions between sexes. Finally, the expression profiles of CsacPBP1 gene were evaluated, and the outcomes further confirm the importance of selecting fitting reference genes for normalization of qRT-PCR data. This study represents the first kind in screening out suitable reference genes for gene expression analysis in C. sacchariphagus. Information from this study is poised to galvanize future inquiry into the gene expression of C. sacchariphagus, an economically important pest of sugarcane.
Full article
(This article belongs to the Section Insect Molecular Biology and Genomics)
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Open AccessReview
Structure and Evolution of Ribosomal Genes of Insect Chromosomes
by
Vladimir E. Gokhman and Valentina G. Kuznetsova
Insects 2024, 15(8), 593; https://doi.org/10.3390/insects15080593 - 4 Aug 2024
Abstract
Currently, clusters of 45S and 5S ribosomal DNA (rDNA) have been studied in about 1000 and 100 species of the class Insecta, respectively. Although the number of insect species with known 45S rDNA clusters (also referred to as nucleolus-organizing regions, or NORs) constitutes
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Currently, clusters of 45S and 5S ribosomal DNA (rDNA) have been studied in about 1000 and 100 species of the class Insecta, respectively. Although the number of insect species with known 45S rDNA clusters (also referred to as nucleolus-organizing regions, or NORs) constitutes less than 0.1 percent of the described members of this enormous group, certain conclusions can already be drawn. Since haploid karyotypes with single 45S and 5S rDNA clusters predominate in both basal and derived insect groups, this character state is apparently ancestral for the class Insecta in general. Nevertheless, the number, chromosomal location, and other characteristics of both 45S and 5S rDNA sites substantially vary across different species, and sometimes even within the same species. There are several main factors and molecular mechanisms that either maintain these parameters or alter them on the short-term and/or long-term scale. Chromosome structure (i.e., monocentric vs. holokinetic chromosomes), excessive numbers of rRNA gene copies per cluster, interactions with transposable elements, pseudogenization, and meiotic recombination are perhaps the most important among them.
Full article
(This article belongs to the Section Insect Molecular Biology and Genomics)
Open AccessArticle
The Fast Evolution of the Stenobothrini Grasshoppers (Orthoptera, Acrididae, and Gomphocerinae) Revealed by an Analysis of the Control Region of mtDNA, with an Emphasis on the Stenobothrus eurasius Group
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Svetlana Sorokina, Nikita Sevastianov, Tatiana Tarasova and Varvara Vedenina
Insects 2024, 15(8), 592; https://doi.org/10.3390/insects15080592 - 3 Aug 2024
Abstract
The two cryptic grasshopper species of the genus Stenobothrus, S. eurasius and S. hyalosuperficies, demonstrate different acoustic behavior despite a strong similarity in morphology. A hybridization between these species is possible in the contact zone; however, there are little molecular data
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The two cryptic grasshopper species of the genus Stenobothrus, S. eurasius and S. hyalosuperficies, demonstrate different acoustic behavior despite a strong similarity in morphology. A hybridization between these species is possible in the contact zone; however, there are little molecular data about the relationships of these species. The analysis of the mtDNA control region (CR) reveals that haplotypes of S. hyalosuperficies have more in common with the more distant Stenobothrus species than with the closely related S. eurasius. In the contact zone, S. eurasius has mt-haplotypes shared with S. hyalosuperficies, which might indicate an introgression of mtDNA from S. hyalosuperficies to the S. eurasius gene pool. We also analyze the structure and evolutionary rate of the mtDNA CR for the Stenobothrus genus and estimate the time of divergence of the species within the genus. The phylogenetic tree of the tribe Stenobothrini reconstructed with either the CR or COI gave the same four groups. The phylogenetic tree of the Stenobothrus genus has a star-like topology with each mtDNA haplotype found in any analyzed species, except S. eurasius, which forms a separate branch. The maximum degree of incomplete lineage sorting can demonstrate either ancestral polymorphism or introgression.
Full article
(This article belongs to the Section Insect Systematics, Phylogeny and Evolution)
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Open AccessArticle
Impact of Neem Seed Extract on Mortality, Esterase and Glutathione-S-Transferase Activities in Thai Polyvoltine Hybrid Silkworm, Bombyx mori L.
by
Ajin Rattanapan and Patcharawan Sujayanont
Insects 2024, 15(8), 591; https://doi.org/10.3390/insects15080591 - 3 Aug 2024
Abstract
Neem, a biopesticide, offers a safer alternative to the synthetic insecticides commonly used in mulberry cultivation, which can harm silkworms. This study aimed to investigate the effects of Thai neem seed extract on all instar larvae of the Thai polyvoltine hybrid silkworm, Bombyx
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Neem, a biopesticide, offers a safer alternative to the synthetic insecticides commonly used in mulberry cultivation, which can harm silkworms. This study aimed to investigate the effects of Thai neem seed extract on all instar larvae of the Thai polyvoltine hybrid silkworm, Bombyx mori L., Dok Bua strains, focusing on the mortality rate and the activities of esterase (EST) and glutathione S-transferases (GST) enzymes. Acute toxicity was assessed using the leaf-dipping method. Results showed that the mortality rate tended to be higher in younger instars than in older ones. The first instar larvae exhibited the highest mortality rate at 94%, whereas the LC50 was highest in the third instar at 5.23 mg L−1 at 72 h. This trend aligns with the activities of EST and GST, which were evaluated in the whole bodies of the first instar larvae and the midgut tissue of fifth instar larvae. As the extract concentration increased, EST activity decreased while GST activity increased in both the first and fifth instar larvae. These findings highlight that neem extract is toxic to all instar larvae, with GST playing a crucial role in detoxification, particularly in the whole body of the Thai polyvoltine hybrid silkworm.
Full article
(This article belongs to the Section Insect Pest and Vector Management)
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Open AccessArticle
Yellow Sticky Cards Reduce the Numbers of Trichogramma dendrolimi (Hymenoptera: Trichogrammatidae) Following Augmentative Releases against the Fruit Borers Carposina sasakii (Lepidoptera: Carposinidae) and Grapholita molesta (Lepidoptera: Tortricidae) in a Pear Orchard
by
Lu Gan, Yanan Wu, J. P. Michaud, Yisong Li, Xiaoxia Liu, Songdou Zhang and Zhen Li
Insects 2024, 15(8), 590; https://doi.org/10.3390/insects15080590 - 3 Aug 2024
Abstract
Integrated pest management relies upon mutual compatibility among pest control tactics. The fruit-boring moths Carposina sasakii and Grapholita molesta can be devastating pests of pome and stone fruit production. Trichogramma dendrolimi parasitizes the eggs of these pests, preventing their eclosion, but its efficacy
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Integrated pest management relies upon mutual compatibility among pest control tactics. The fruit-boring moths Carposina sasakii and Grapholita molesta can be devastating pests of pome and stone fruit production. Trichogramma dendrolimi parasitizes the eggs of these pests, preventing their eclosion, but its efficacy can be reduced by other pest control tactics. We tested T. dendrolimi attraction to five colors, and moth attraction to six colors, in laboratory choice tests, and thereafter deployed yellow sticky cards in tandem with releases of T. dendrolimi in field trials in a pear orchard. Yellow sticky cards deployed at high density trapped T. dendrolimi and reduced their numbers post-release. They also trapped adult G. molesta, which appeared to compensate for reduced egg parasitism on this species, but not on C. sasakii, which had higher abundance in plots with yellow sticky cards. The cards also captured adult lacewings, likely reducing their numbers in the field, but did not capture large numbers of lady beetles. The results suggest that yellow sticky cards can be used at high density to control aphids, psyllids and leafhoppers in early spring (March and April) when natural enemies are in low numbers, then removed in May so as not to interfere with augmentative releases of T. dendrolimi that must be timed to coincide with peak flights of fruit-boring moths. This strategy should enhance the compatibility of yellow sticky cards with egg parasitoid releases.
Full article
(This article belongs to the Section Insect Pest and Vector Management)
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Graphical abstract
Open AccessArticle
A Transcriptome Analysis of Poncirus trifoliata, an Aurantioideae Species Tolerant to Asian Citrus Psyllid, Has Identified Potential Genes and Events Associated with Psyllid Resistance
by
Xinyou Wang, Haoran Ji, Leijian Zhong, Wei Zeng, Zhigang Ouyang and Ruimin Li
Insects 2024, 15(8), 589; https://doi.org/10.3390/insects15080589 - 2 Aug 2024
Abstract
Citrus huanglongbing (HLB) is a devastating disease for citrus production, largely caused by the Asian citrus psyllid (ACP). Poncirus trifoliata exhibits high resistance to ACP; however, this resistance is weakened when C. sinensis is co-cultivated. This study aimed to identify the differentially expressed
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Citrus huanglongbing (HLB) is a devastating disease for citrus production, largely caused by the Asian citrus psyllid (ACP). Poncirus trifoliata exhibits high resistance to ACP; however, this resistance is weakened when C. sinensis is co-cultivated. This study aimed to identify the differentially expressed genes (DEGs) during ACP feeding and to uncover potential ACP resistance genes in P. trifoliata. In comparison to independent cultivation, 1247 and 205 DEGs were identified in P. trifoliata when co-cultivated with C. sinensis after 7 and 14 days, respectively. Analysis of enriched Gene Ontology categories revealed that DEGs were significantly associated with the cell wall, glucometabolic activities, and secondary metabolites. Additionally, these genes were found to be involved in phytohormone signaling, cell wall metabolism, redox state homeostasis, and secondary metabolites, as well as a number of transcription factor genes (TFs). Furthermore, we examined the impact of the ACP feeding factor on the gene expression patterns in P. trifoliata. Results showed an increase in the JA signaling pathway and various TFs. The RNA-seq results were verified using reverse transcription quantitative PCR. Our findings shed light on the molecular basis of ACP resistance in P. trifoliata and identified potential genes associated with this resistance.
Full article
(This article belongs to the Section Insect Molecular Biology and Genomics)
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Open AccessArticle
Impacts of Combining Steinernema carpocapsae and Bracon hebetor Parasitism on Galleria mellonella Larvae
by
Neama A. Aamer, Zeinab A. El-Moaty, Maria Augustyniak, Lamia M. El-Samad and Hanaa S. Hussein
Insects 2024, 15(8), 588; https://doi.org/10.3390/insects15080588 - 1 Aug 2024
Abstract
The greater wax moth, Galleria mellonella, is a significant pest in apiculture and a well-established model organism for immunological and ecotoxicological studies. This investigation explores the individual and combined effects of the ectoparasite Bracon hebetor (B.h.) and the entomopathogenic nematode Steinernema carpocapsae
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The greater wax moth, Galleria mellonella, is a significant pest in apiculture and a well-established model organism for immunological and ecotoxicological studies. This investigation explores the individual and combined effects of the ectoparasite Bracon hebetor (B.h.) and the entomopathogenic nematode Steinernema carpocapsae (S.c.) on G. mellonella larvae. We evaluated the activity of oxidative stress enzymes, including superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST), malondialdehyde (MDA) levels, cytochrome P450 activity, cell viability using Annexin V-FITC, DNA damage via comet assay, and larval morphology through scanning electron microscopy (SEM). Control larvae exhibited higher GPx and GST activities compared to those treated with B.h., S.c., or the B.h. + S.c. combination. Conversely, MDA levels displayed the opposite trend. SOD activity was reduced in the B.h. and S.c. groups but significantly higher in the combined treatment. Cytochrome P450 activity increased in response to parasitism by B. hebetor. The Annexin V-FITC assay revealed decreased cell viability in parasitized groups (B.h. 79.4%, S.c. 77.3%, B.h. + S.c. 70.1%) compared to controls. DNA damage analysis demonstrated significant differences between groups, and SEM observations confirmed severe cuticle abnormalities or malformations in G. mellonella larvae. These findings highlight the complex interactions between B. hebetor, S. carpocapsae, and their host, G. mellonella. Additionally, they illuminate the intricate physiological responses triggered within the host larvae.
Full article
(This article belongs to the Special Issue Host Specificity of Parasitoid Wasps and Its Applications in Biological Control)
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Open AccessArticle
Assessment of Lambda-Cyhalothrin and Spinetoram Toxicity and Their Effects on the Activities of Antioxidant Enzymes and Acetylcholinesterase in Honey Bee (Apis mellifera) Larvae
by
Ji-Yeong Choi, Kyongmi Chon, Juyeong Kim, Bala Murali Krishna Vasamsetti, Bo-Seon Kim, Chang-Young Yoon, Sojeong Hwang, Kyeong-Hun Park and Ji-Hoon Lee
Insects 2024, 15(8), 587; https://doi.org/10.3390/insects15080587 - 1 Aug 2024
Abstract
Honeybees play a crucial role as agricultural pollinators and are frequently exposed to various pollutants, including pesticides. In this study, we aimed to evaluate the toxicity of lambda-cyhalothrin (LCY) and spinetoram (SPI) in honey bee larvae reared in vitro through single (acute) and
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Honeybees play a crucial role as agricultural pollinators and are frequently exposed to various pollutants, including pesticides. In this study, we aimed to evaluate the toxicity of lambda-cyhalothrin (LCY) and spinetoram (SPI) in honey bee larvae reared in vitro through single (acute) and repeated (chronic) exposure. The acute LD50 values for LCY and SPI were 0.058 (0.051–0.066) and 0.026 (0.01–0.045) μg a.i./larva, respectively. In chronic exposure, the LD50 values of LCY and SPI were 0.040 (0.033–0.046) and 0.017 (0.014–0.019) μg a.i./larva, respectively. The chronic no-observed-effect dose of LCY and SPI was 0.0125 μg a.i./larva. Adult deformation rates exceeded 30% in all LCY treatment groups, showing statistically significant differences compared to the solvent control group (SCG). Similarly, SPI-treated bees exhibited significantly more deformities than SCG. Furthermore, we examined the activities of several enzymes, namely, acetylcholinesterase (AChE), glutathione-S-transferase (GST), catalase (CAT), and superoxide dismutase (SOD), in larvae, pupae, and newly emerged bees after chronic exposure at the larval stage (honey bee larval chronic LD50, LD50/10 (1/10th of LD50), and LD50/20 (1/20th of LD50)). LCY and SPI induced significant changes in detoxification (GST), antioxidative (SOD and CAT), and signaling enzymes (AChE) during the developmental stages (larvae, pupae, and adults) of honey bees at sublethal and residue levels. Our results indicate that LCY and SPI may affect the development of honey bees and alter the activity of enzymes associated with oxidative stress, detoxification, and neurotransmission. These results highlight the potential risks that LCY and SPI may pose to the health and normal development of honey bees.
Full article
(This article belongs to the Special Issue Toxicology and Molecular Physiology of Social Insects)
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Open AccessArticle
Chlorantraniliprole Enhances Cellular Immunity in Larvae of Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae)
by
Qingyan Liu, Xiaoyue Deng, Liuhong Wang, Wenqi Xie, Huilai Zhang, Qing Li, Qunfang Yang and Chunxian Jiang
Insects 2024, 15(8), 586; https://doi.org/10.3390/insects15080586 - 1 Aug 2024
Abstract
The innate immunity of insects encompasses cellular and humoral defense mechanisms and constitutes the primary defense against invading microbial pathogens. Cellular immunity (phagocytosis, nodulation, and encapsulation) is primarily mediated by hemocytes. Plasmatocytes and granulocytes play an important role and require changes in the
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The innate immunity of insects encompasses cellular and humoral defense mechanisms and constitutes the primary defense against invading microbial pathogens. Cellular immunity (phagocytosis, nodulation, and encapsulation) is primarily mediated by hemocytes. Plasmatocytes and granulocytes play an important role and require changes in the cytoskeletons of hemocytes. However, research investigating the immunological impacts of insecticides on the fall armyworm (FAW), Spodoptera frugiperda, remains scarce. Therefore, we conducted a study to investigate the effects of chlorantraniliprole exposure on cellular immunity in FAW larvae. Our findings revealed the presence of five types of hemocytes in the larvae: prohemocytes, plasmatocytes, granulocytes, oenocytoids, and spherulocytes. The LD10, LD20, and LD30 of chlorantraniliprole affected both the morphology and total count of some hemocytes in the larvae. Moreover, larvae exposed to chlorantraniliprole showed increased phagocytosis, nodulation, and encapsulation. To determine the mechanism of the enhanced cellular immunity, we studied plasmatocytes in the spread state and the cytoskeleton in hemocytes. It was found that the spreading ratio of plasmatocytes and the areas of the cytoskeletons in hemocytes were increased after chlorantraniliprole treatment. These results suggest that exposure to chlorantraniliprole results in an enhanced immune response function in FAW larvae, which may be mediated by cytoskeletal changes and plasmatocyte spreading. Consequently, this study provides valuable insights into the cellular immune response of FAW larvae to insecticide exposure.
Full article
(This article belongs to the Special Issue Research on Insect Interactions with Symbionts and Pathogens)
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Open AccessArticle
An Improved Bulk DNA Extraction Method for Detection of Helicoverpa armigera (Lepidoptera: Noctuidae) Using Real-Time PCR
by
Kayla A. Mollet, Luke R. Tembrock, Frida A. Zink, Alicia E. Timm and Todd M. Gilligan
Insects 2024, 15(8), 585; https://doi.org/10.3390/insects15080585 - 1 Aug 2024
Abstract
Helicoverpa armigera is among the most problematic agricultural pests worldwide due to its polyphagy and ability to evolve pesticide resistance. Molecular detection methods for H. armigera have been developed to track its spread, as such methods allow for rapid and accurate differentiation from
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Helicoverpa armigera is among the most problematic agricultural pests worldwide due to its polyphagy and ability to evolve pesticide resistance. Molecular detection methods for H. armigera have been developed to track its spread, as such methods allow for rapid and accurate differentiation from the native sibling species H. zea. Droplet digital PCR (ddPCR) is a preferred method for bulk screening due to its accuracy and tolerance to PCR inhibitors; however, real-time PCR is less expensive and more widely available in molecular labs. Improvements to DNA extraction yield, purity, and throughput are crucial for real-time PCR assay optimization. Bulk DNA extractions have recently been improved to where real-time PCR sensitivity can equal that of ddPCR, but these new methods require significant time and specialized equipment. In this study, we improve upon previously published bulk DNA extraction methods by reducing bench time and materials. Our results indicate that the addition of caffeine and RNase A improves DNA extraction, resulting in lower Cq values during real-time PCR while reducing the processing time and cost per specimen. Such improvements will enable the use of high throughput screening methods across multiple platforms to improve the probability of detection of H. armigera.
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(This article belongs to the Section Insect Molecular Biology and Genomics)
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Open AccessArticle
Monitoring Mosquito Abundance: Comparing an Optical Sensor with a Trapping Method
by
Topu Saha, Adrien P. Genoud, Gregory M. Williams, Gareth J. Russell and Benjamin P. Thomas
Insects 2024, 15(8), 584; https://doi.org/10.3390/insects15080584 - 1 Aug 2024
Abstract
Optical sensors have shown significant promise in offering additional data to track insect populations. This article presents a comparative study between abundance measurements obtained from a novel near-infrared optical sensor and physical traps. The optical instrument, named an Entomological Bistatic Optical Sensor System,
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Optical sensors have shown significant promise in offering additional data to track insect populations. This article presents a comparative study between abundance measurements obtained from a novel near-infrared optical sensor and physical traps. The optical instrument, named an Entomological Bistatic Optical Sensor System, or eBoss, is a non-destructive sensor operating in the near-infrared spectral range and designed to continuously monitor the population of flying insects. The research compares the mosquito aerial density (#/m3) obtained through the eBoss with trap counts from eight physical traps during an eight-month field study. The eBoss recorded over 302,000 insect sightings and assessed the aerial density of all airborne insects as well as male and female mosquitoes specifically with a resolution of one minute. This capability allows for monitoring population trends throughout the season as well as daily activity peaks. The results affirmed the correlation between the two methods. While optical instruments do not match traps in terms of taxonomic accuracy, the eBoss offered greater temporal resolution (one minute versus roughly three days) and statistical significance owing to its much larger sample size. These outcomes further indicate that entomological optical sensors can provide valuable complementary data to more common methods to monitor flying insect populations, such as mosquitoes or pollinators.
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(This article belongs to the Special Issue Breakthrough Technologies for Future Entomology)
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Open AccessArticle
Mapping the Distribution of Curculio davidi Fairmaire 1878 under Climate Change via Geographical Data and the MaxEnt Model (CMIP6)
by
Junhao Wu, Xinju Wei, Zhuoyuan Wang, Yaqin Peng, Biyu Liu and Zhihang Zhuo
Insects 2024, 15(8), 583; https://doi.org/10.3390/insects15080583 - 31 Jul 2024
Abstract
Curculio davidi is a major pest in chestnut-producing regions in China, and there have been many studies on its occurrence, biological characteristics, and management strategies. However, few of them have focused on the distribution changes of the pest under climate change. In this
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Curculio davidi is a major pest in chestnut-producing regions in China, and there have been many studies on its occurrence, biological characteristics, and management strategies. However, few of them have focused on the distribution changes of the pest under climate change. In this study, the MaxEnt model (version 3.3.4) and ArcGIS software (version 10.8) were first employed to map the current and future (2050 s and 2080 s) suitable habitat distribution of the weevil under climate change (CMIP 6: SSP1-2.6, SSP2-4.5, and SSP5-8.5). The results indicate that the highly suitable areas for C. davidi are mainly concentrated in Hubei, Henan, Anhui, Jiangxi, Jiangsu, Zhejiang, the coastal areas of Shandong, and eastern Guizhou, northwestern Hunan, and northeastern Sichuan provinces in China. Through the Jackknife test of 19 climate factors, six climate factors affecting the distribution of C. davidi were identified, with precipitation from July (Prec7), precipitation of warmest quarter (Bio18), and temperature seasonality (standard deviation × 100) (Bio4) contributing a combined percentage of 86.3%. Under three different climate scenarios (CMIP 6: SSP1-2.6, SSP2-4.5, and SSP5-8.5), the area of moderately suitable regions is projected to increase by 22.12–27.33% in the 2050 s and by 17.80–38.22% in the 2080 s compared to the current distribution, while the area of highly suitable regions shows a shrinking trend. This study provides data support for the management strategies of C. davidi and offers new insights into the dynamic changes of similar forestry pests.
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(This article belongs to the Section Insect Pest and Vector Management)
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Open AccessArticle
Discovering Native Ant Species with the Potential to Suppress Red Imported Fire Ants
by
Meihong Ni, Xinyi Yang, Yiran Zheng, Yuan Wang and Mingxing Jiang
Insects 2024, 15(8), 582; https://doi.org/10.3390/insects15080582 - 31 Jul 2024
Abstract
Native ants have long been considered for their potential to suppress the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), a highly invasive and destructive species. However, the knowledge in this field is limited to behavioral observations of a few related native
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Native ants have long been considered for their potential to suppress the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), a highly invasive and destructive species. However, the knowledge in this field is limited to behavioral observations of a few related native ants. In this study, by setting up a series of ant combinations of three native ants, i.e., Monomorium chinense Santschi, the robust crazy ant Nylanderia bourbonica Forel, and Iridomyrmex anceps Roger, with S. invicta, we observed the aggression levels and mortality rates. Using baited vials, we also investigated the abundance of native ants in four types of habitats in Eastern China that are preferred by S. invicta (woodland, green belts on roadsides, grassland, and farmland), as well as their seasonal abundance when co-existing with S. invicta and their spatial distribution before and after control of S. invicta. We found that M. chinense and N. bourbonica show a degree of aggression towards S. invicta and can kill substantial proportions of S. invicta under laboratory conditions, but I. anceps does not. Both M. chinense and N. bourbonica can occur in each type of habitat investigated and are more abundant in green belts (particularly lawns with turf) and grasslands relative to other habitats. In grasslands with S. invicta, M. chinense maintained a low density before early July; however, its abundance increased thereafter and reached a peak in September. N. bourbonica also had a low density early in the season and increased steadily from April. Its abundance began to decrease substantially from November. In grasslands invaded by S. invicta, both M. chinense and N. bourbonica were restricted to sites close to the margins before S. invicta was controlled; however, they spread to a larger range within a few weeks after control of S. invicta. In conclusion, M. chinense and N. bourbonica have the potential to suppress S. invicta invasion in habitats that are abundant with these two native ants.
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(This article belongs to the Section Insect Societies and Sociality)
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Open AccessArticle
Molecular Detection and Analysis of Trypanosoma (Megatrypanum) spp. Diversity in Tabanidae (Diptera) Collected in Lithuania
by
Jurga Turčinavičienė, Rasa Bernotienė and Andrius Petrašiūnas
Insects 2024, 15(8), 581; https://doi.org/10.3390/insects15080581 - 30 Jul 2024
Abstract
Trypanosomatids from the Tabanidae family have not been studied in Lithuania in any detail. In this study, a nested PCR amplifying the DNA fragment coding the SSU rRNA was used to determine the Trypanosoma spp. prevalence and diversity in the Tabanidae family collected
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Trypanosomatids from the Tabanidae family have not been studied in Lithuania in any detail. In this study, a nested PCR amplifying the DNA fragment coding the SSU rRNA was used to determine the Trypanosoma spp. prevalence and diversity in the Tabanidae family collected in Lithuania in 2018–2019. In total, 101 Tabanidae individuals were investigated from six areas in Lithuania, and 14 different species were identified. The overall positivity of Trypanosoma spp. DNA in tabanids was 50.5% (51/101). Tabanus maculicornis was the most abundant species and yielded the highest prevalence of trypanosomatids (84.62%, 22/26), while Hybomitra nitidifrons showed a high prevalence as well, reaching 77.8% (14/18). In flies of some species (Hybomitra lapponica and Hybomitra lurida), Trypanosoma was detected for the first time. Nine different haplotypes were detected as being distributed in different tabanid species. Analysis showed that most sequences obtained during our study were identical or extremely close to two major T. theileri subclades: TthI and TthII. Our data analysis suggests the presence of different Trypanosoma genotypes in the same tabanid species, meaning that different lineages of Trypanosoma could be more related to the vertebrate host and not the fly species. This is the first study of trypanosomatid parasites in tabanids from Lithuania, and our results are valuable in providing data on the diversity of these parasites in different Tabanidae species.
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(This article belongs to the Special Issue Flies of Veterinary Importance: Biology, Ecology and Control)
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Open AccessArticle
A New Endemic Locality of Dermacentor reticulatus in Central–Southern Poland and Its Potential Epidemiological Implications
by
Marek Asman, Katarzyna Bartosik, Justyna Jakubas-Zawalska, Agata Świętek and Joanna Witecka
Insects 2024, 15(8), 580; https://doi.org/10.3390/insects15080580 - 30 Jul 2024
Abstract
Dermacentor reticulatus (Acari: Ixodidae) is an important arthropod vector in medical and veterinary contexts. Its geographic range is divided into western and eastern populations separated by a “Dermacentor-free zone” in central Poland. Recent faunistic studies showed a new endemic locality of
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Dermacentor reticulatus (Acari: Ixodidae) is an important arthropod vector in medical and veterinary contexts. Its geographic range is divided into western and eastern populations separated by a “Dermacentor-free zone” in central Poland. Recent faunistic studies showed a new endemic locality of the species in Upper Silesia to the west of the Vistula River (central–southern Poland) and its co-occurrence with I. ricinus. The prevalence of five tick-borne pathogens (TBPs), e.g., B. burgdorferi s.l., Bartonella spp., Rickettsia spp., and Babesia spp., in the ticks was assessed with polymerase chain reaction (PCR) methods. The molecular studies revealed the presence of Rickettsia spp. in 23.8% of the D. reticulatus specimens. In turn, 94.1% of the I. ricinus adults were infected with B. burgdorferi s.l., 11.7 % with Babesia spp., and 5.8% with Rickettsia spp. Coinfections with two TBPs were noted in 17.6% of the I. ricinus. These findings highlight not only the risk of infestation by both tick species in an area previously considered Dermacentor-free, but also the high prevalence of TBPs in the study area. Increased focus on medical and veterinary services appears necessary to diagnose and prevent tick-borne diseases in this region.
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(This article belongs to the Section Medical and Livestock Entomology)
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Open AccessArticle
Characterization of the Spatial Distribution of the Pepper Weevil, Anthonomus eugenii Cano (Col.: Curculionidae), in Pepper Fields in South Florida
by
Victoria O. Adeleye, Dakshina R. Seal, Xavier Martini, Geoffrey Meru and Oscar E. Liburd
Insects 2024, 15(8), 579; https://doi.org/10.3390/insects15080579 - 30 Jul 2024
Abstract
The pepper weevil, Anthonomus eugenii Cano, is an economically important pest of cultivated peppers (Capsicum annuum) in tropical and subtropical regions of the world. This study aimed to ascertain the spatial distribution of pepper weevil infestation across various fields in Miami
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The pepper weevil, Anthonomus eugenii Cano, is an economically important pest of cultivated peppers (Capsicum annuum) in tropical and subtropical regions of the world. This study aimed to ascertain the spatial distribution of pepper weevil infestation across various fields in Miami Dade County, South Florida. The spatio-temporal dynamics of pepper weevil were evaluated using 144 sample points within each of seven pepper fields. The data were analyzed using three different geospatial techniques, spatial analysis by distance indices (SADIE), Moran’s I, and Geary’s C, to determine the spatial distribution of pepper weevil. The SADIE analysis revealed a significant aggregation distribution in 18 out of 30 sampling dates across all fields. The results from Geary’s C and Moran’s I indices indicated a positive spatial autocorrelation (spatial clustering/aggregation) of pepper weevil regardless of field or pepper types. Overall, the findings from this study depict an aggregated spatial distribution pattern of pepper weevil populations, characterized by a tendency for aggregation that transitions to a more uniform distribution as the season progresses.
Full article
(This article belongs to the Section Insect Pest and Vector Management)
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