Insects

14 pages, 3601 KiB

Open AccessArticle

CRISPR/Cas9-Mediated Knockout of BmGDAP2 in the Silkworm, Bombyx mori: Extended Lifespan and Altered Gene Expression Impacting Developmental Pathways

by Chaojun Yuan, Zichong Zhou, Qifeng Guo, Ying Yang, Yue Sun, Yong Liu, Wenyi Jia, Shuoqi Fan, Jinxin Wu, Xiaoting Hua, Ping Lin, Ping Zhao and Qingyou Xia

Insects 2025, 16(4), 354; https://doi.org/10.3390/insects16040354 (registering DOI) - 27 Mar 2025

Abstract

Ganglioside-induced differentiation-associated protein 2 (GDAP2) is a gene involved in hereditary cerebellar ataxia. At present, little is known about the function of GDAP2 in insects. In this study, BmGDAP2 was detected to be highly expressed in the head, epidermis, midgut, and [...] Read more.

Ganglioside-induced differentiation-associated protein 2 (GDAP2) is a gene involved in hereditary cerebellar ataxia. At present, little is known about the function of GDAP2 in insects. In this study, BmGDAP2 was detected to be highly expressed in the head, epidermis, midgut, and anterior silk glands of silkworms. We generated a knockout mutant, BmGDAP2 (BmGDAP2^KO), using the CRISPR/Cas9 system. Compared with that of the wild-type, the growth cycle of BmGDAP2^KO larvae was significantly prolonged, while their body size was reduced. Furthermore, we found 149 differentially expressed genes (DEGs) between BmGDAP2^KO and the wild-type, including 106 upregulated and 43 downregulated genes. GO annotation analysis indicated that BmGDAP2 primarily influences structural and molecular activities, as well as catalytic and binding functions. KEGG pathway analysis revealed that the differentially expressed genes were mainly enriched in pathways related to peroxidase activity, hormone synthesis, apoptosis, and longevity regulation. Further investigation focused on candidate genes related to these pathways. We found that the expression levels of MAD2L1, which can inhibit cell proliferation and promote apoptosis, and Aurka-b, which plays a crucial role in cell cycle regulation, were significantly reduced in BmGDAP2^KO silkworms. These changes may interfere with the normal functions of cell division, leading to the prolonged developmental cycle observed in BmGDAP2^KO larvae. Our findings demonstrate that knockout of BmGDAP2 significantly prolongs the life cycle of Bombyx mori by affecting genes related to autophagy, apoptosis, and hormone regulation. Full article

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

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13 pages, 261 KiB

Open AccessArticle

Evaluation of Selected Plant Essential Oils for Aphid Pest Control in Integrated Pest Management

by José Luis Casas, María López Santos-Olmo, Aitor Sagarduy-Cabrera and Mᵃ Ángeles Marcos-García

Insects 2025, 16(4), 353; https://doi.org/10.3390/insects16040353 (registering DOI) - 27 Mar 2025

Abstract

Aphids are major agricultural pests, feeding on plant sap and transmitting viruses to economically important crops. The use of synthetic pesticides is increasingly restricted due to stricter regulations aimed at protecting both human and environmental health. To address this challenge, we investigated the [...] Read more.

Aphids are major agricultural pests, feeding on plant sap and transmitting viruses to economically important crops. The use of synthetic pesticides is increasingly restricted due to stricter regulations aimed at protecting both human and environmental health. To address this challenge, we investigated the potential of essential oils (EOs) extracted from rosemary (Salvia rosmarinus Spenn.), laurel (Laurus nobilis L.), and cypress (Cupressus sempervirens L.) as alternatives to synthetic insecticides, while ensuring compatibility with biological control strategies. The EOs were extracted via hydrodistillation, diluted in acetone, and tested against the aphid Myzus persicae and its natural predator, the hoverfly (Sphaerophoria rueppellii). Aphid mortality was dose-dependent, reaching 85% with rosemary EO, 83% with laurel, and 81% with cypress. In contrast, hoverfly larvae mortality remained low, with a maximum of 20%, which could largely be attributed to the solvent used in the assays. These promising results support further research to develop effective EO-based tools for integrated pest management. Full article

(This article belongs to the Special Issue Protecting Field Crops from Economically Damaging Aphid Infestation)

16 pages, 7250 KiB

Open AccessArticle

Interspecific Mating Is Trivial and Asymmetrical Between Two Destructive Anoplophora Beetles

by Tian Xu, Wenbo Wang, Xiaoyuan Chen, Jing Ma, Ruixu Chen, Xue Sun, Yang Yang, Guohao Li, Yadi Deng and Dejun Hao

Insects 2025, 16(4), 352; https://doi.org/10.3390/insects16040352 (registering DOI) - 27 Mar 2025

Abstract

The Asian longhorn beetle (ALB), Anoplophora glabripennis, and citrus longhorn beetle (CLB), Anoplophora chinensis, are two destructive invasive wood-boring pests, with high similarities in morphology, geographical distribution, host range, life cycle, adult behaviors and male-produced pheromone, implying a potential existence of [...] Read more.

The Asian longhorn beetle (ALB), Anoplophora glabripennis, and citrus longhorn beetle (CLB), Anoplophora chinensis, are two destructive invasive wood-boring pests, with high similarities in morphology, geographical distribution, host range, life cycle, adult behaviors and male-produced pheromone, implying a potential existence of interspecific interactions. Matings have been found to occur across females and males of the two species when manually paired in confined spaces. However, interspecific mating and its regulating factors are unclear between sympatric populations on hosts. Herein, by observing mountings and tracking the beetles that freely coexisted on host branches in cages, we found that the majority of mountings appeared within species; however, interspecific mountings occasionally occurred between male CLBs and female ALBs. The CLB was more active than the ALB at night. It seems that males actively searched for female ALBs, while the inverse was the case with CLBs. The main release periods of shared pheromone components overlapped between the two species, while compound ratios had significant differences. Our results unveil a trivial and asymmetrical interspecific mating between ALBs and CLBs, implying a risk of co-outbreaks of the two species in either native or invaded areas. Full article

(This article belongs to the Special Issue Bark and Wood-Boring Insects: Past and Present Research and Essential Future Knowledge—2nd Edition)

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12 pages, 1117 KiB

Open AccessReview

An Overview of the Adverse Impacts of Old Combs on Honeybee Colonies and Recommended Beekeeping Management Strategies

by Qingxin Meng, Rong Huang, Shunhua Yang, Wutao Jiang, Yakai Tian and Kun Dong

Insects 2025, 16(4), 351; https://doi.org/10.3390/insects16040351 (registering DOI) - 27 Mar 2025

Abstract

The honeybee comb serves as the primary site for all essential colony activities, and its structural and functional integrity plays a crucial role in colony development. As combs age through successive brood-rearing cycles, their physicochemical properties undergo significant changes, which can negatively affect [...] Read more.

The honeybee comb serves as the primary site for all essential colony activities, and its structural and functional integrity plays a crucial role in colony development. As combs age through successive brood-rearing cycles, their physicochemical properties undergo significant changes, which can negatively affect colony health and productivity. This review synthesizes the current knowledge on the biological functions of combs, the aging process, and the negative impacts of old combs on cell structure, worker morphology, colony strength, and bee product quality. Additionally, it examines the adaptive strategies employed by honeybees and the recommended beekeeping management practices to mitigate these effects. Specifically, old combs undergo structural changes in cell dimensions and reduced spatial capacity, leading to the growth of smaller bees with diminished foraging and productivity. Furthermore, bee products, such as honey and beeswax, collected from old combs demonstrate compromised quality and higher levels of environmental contaminants. To counteract these challenges, colonies engage in hygienic behaviors, such as cell cleaning and comb rebuilding, while their enhanced immune and detoxification systems help mitigate comb-derived stressors. This review demonstrates that the systematic replacement of old brood combs is a critical management strategy to optimize bee health and ensure sustainable apiculture. Full article

(This article belongs to the Special Issue Advances in the Health, Behavior, and Physiology of Honeybees and Other Pollinators)

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17 pages, 500 KiB

Open AccessReview

Environmental Sources of Possible Associated Pathogens and Contaminants of Stingless Bees in the Neotropics

by Joseline Sofía Ocaña-Cabrera, Sarah Martin-Solano and Claude Saegerman

Insects 2025, 16(4), 350; https://doi.org/10.3390/insects16040350 (registering DOI) - 27 Mar 2025

Abstract

Stingless bees are crucial for pollination and support diverse ecological relationships, offering economic benefits and contributing to enhanced crop yields. Their tropical pollinator status makes them highly sensitive to environmental changes and disruptions, which could affect their survival, as well as to pathogens [...] Read more.

Stingless bees are crucial for pollination and support diverse ecological relationships, offering economic benefits and contributing to enhanced crop yields. Their tropical pollinator status makes them highly sensitive to environmental changes and disruptions, which could affect their survival, as well as to pathogens that threaten their health. The lack of comprehensive research and the scattering of reports make it difficult to identify pathogens and contaminants. This review aims to provide an overview of diseases in stingless bees, examine chemical contaminants in their products, and explore threatened sources. Using the PRISMA flowchart, a total of 30 articles from 2009 to 2024 concerning pathogens and contaminants in stingless bees were retrieved. A total of 15 pathogens and 26 pollutants affect life expectancy and survival rate of stingless bees (mainly the genera Melipona and Tetragonisca) were identified in five major areas of the Neotropics, including Brazil, Mexico, Costa Rica, Australia, and Asia. Studies indicated that the bacterial genera Pseudomonas, Melissococcus, and Lysinibacillus are affecting the survival of stingless bees, particularly their brood, and contributing to annual colony deaths. Heavy metals, polycyclic aromatic hydrocarbons (PAHs), and microplastics have been detected in by-products of stingless bees, especially honey. Epidemiological research is crucial, including studies on pathogens associated with diseases, the effects of contaminants on bees, and the development of quality guidelines for stingless-bee products. Full article

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

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14 pages, 4119 KiB

Open AccessArticle

Abundance of the Dominant Endosymbiont Rickettsia and Fitness of the Stored-Product Pest Liposcelis bostrychophila (Psocoptera: Liposcelididae)

by Chunqi Bai, Yiwen Duan, Chao Zhao, Lei Yan, Duangsamorn Suthisut, Jianhua Lü, Yueliang Bai, Fangfang Zeng and Meng Zhang

Insects 2025, 16(4), 349; https://doi.org/10.3390/insects16040349 (registering DOI) - 27 Mar 2025

Abstract

Endosymbiotic bacteria are key factors that regulate the biological traits of Liposcelis bostrychophila. This study employed metagenomic methods to analyze the dominant species of symbiotic microorganisms associated with L. bostrychophila. By controlling the environmental temperature, we were able to manipulate the [...] Read more.

Endosymbiotic bacteria are key factors that regulate the biological traits of Liposcelis bostrychophila. This study employed metagenomic methods to analyze the dominant species of symbiotic microorganisms associated with L. bostrychophila. By controlling the environmental temperature, we were able to manipulate the abundance of endosymbionts and establish populations with high, medium, and low levels of these bacteria. This allowed us to examine the fitness parameters of L. bostrychophila under different levels of endosymbiont abundance. The experimental results revealed that L. bostrychophila hosts 51 genera of symbiotic microorganisms, with Rickettsia being the dominant genus, accounting for 84.11% to 98.16% of the total share. Environmental temperature significantly affected the abundance of Rickettsia, with notable differences observed during the adult stage of L. bostrychophila. A temperature gradient of 28 °C, 35 °C, and 37 °C was established, allowing for the classification of populations based on Rickettsia abundance into three categories: high-abundance populations (LBhp), medium-abundance populations (LBmp), and low-abundance populations (LBlp). The abundance of Rickettsia had a significant impact on the fitness of L. bostrychophila. Specifically, a high abundance of Rickettsia contributed positively to population fitness by increasing egg production, prolonging egg hatching time, enhancing lifespan, and improving both survival and reproductive rates. Therefore, the endosymbiont Rickettsia plays a crucial role in the growth and development of L. bostrychophila. In the future, our research will help further uncover the interactions between Rickettsia and its host, providing new perspectives for pest control and offering a better understanding of insect biology and ecology. Full article

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

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13 pages, 2470 KiB

Open AccessArticle

Additive Insecticidal Effects of Chitosan/dsRNA Nanoparticles Targeting V-ATPaseD and Emamectin Benzoate–Lufenuron Formulations Against Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

by Shigang Guo, Zhongwei Li, Xuhui Zhao, Donghai Zhang, Camilo Ayra-Pardo, Yunchao Kan and Dandan Li

Insects 2025, 16(4), 348; https://doi.org/10.3390/insects16040348 (registering DOI) - 27 Mar 2025

Abstract

The fall armyworm, Spodoptera frugiperda, a lepidopteran pest from the family Noctuidae, has become a major invasive pest since 2016. Using RNAi methods to control S. frugiperda is currently under investigation. This study is the first to target the V-ATPaseD gene of [...] Read more.

The fall armyworm, Spodoptera frugiperda, a lepidopteran pest from the family Noctuidae, has become a major invasive pest since 2016. Using RNAi methods to control S. frugiperda is currently under investigation. This study is the first to target the V-ATPaseD gene of S. frugiperda using RNAi. Injection of dsRNA-V-ATPaseD into the hemolymph of 4th-instar larvae significantly suppressed gene expression at 24 and 48 h post-injection. Treated larvae showed delayed development and reduced pupation after 7 days. Subsequently, V-ATPaseD silencing was achieved through topical or oral administration of chitosan/dsRNA-V-ATPaseD nanoparticles. Larvae fed these nanoparticles exhibited significant reductions in V-ATPaseD mRNA at 72 h, persisting until 96 h before normalizing. Additionally, the treated larvae displayed disrupted molting and impaired pupation. Furthermore, larvae fed chitosan/dsRNA-V-ATPaseD were more susceptible to emamectin benzoate–lufenuron at LC30 concentrations, resulting in 68% mortality—27% higher than the pesticide alone—72 h post-exposure. Combining chitosan/dsRNA-V-ATPaseD nanoparticles with emamectin benzoate–lufenuron significantly enhanced pest control efficacy, providing new insights into pesticide reduction and sustainable pest control methods for this invasive species. Full article

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

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13 pages, 2095 KiB

Open AccessArticle

The Dangers of Growing Old: Adult Moths Face Higher Predation Pressures than Caterpillars in Hyles lineata

by Braulio A. Sanchez, Oceane Da Cunha, Jackson W. Savage, L. Miles Horne, Sol Saenz-Arreola, Kajaya Pollard, Oliver Neria, Spencer Duffendack, Simon Terrazas, Javier M. Diaz, John Deitsch and Brett M. Seymoure

Insects 2025, 16(4), 347; https://doi.org/10.3390/insects16040347 (registering DOI) - 27 Mar 2025

Abstract

Holometabolous insects display drastically different morphologies across life stages (i.e., larvae vs. adults). Morphological differences across life stages, such as different sizes and coloration, likely result in differential survival, as predators may find individuals of one life stage more conspicuous and/or more energetically [...] Read more.

Holometabolous insects display drastically different morphologies across life stages (i.e., larvae vs. adults). Morphological differences across life stages, such as different sizes and coloration, likely result in differential survival, as predators may find individuals of one life stage more conspicuous and/or more energetically profitable than another. Furthermore, prey conspicuousness may vary temporally because both the sensory environment and predator sensory abilities differ between day and night. Here, we investigated how the interaction between life stage (caterpillar vs. moth) and time of day (day vs. night) influences predation of the white-lined sphinx (Lepidoptera: Hyles lineata). We predicted that caterpillars would be less susceptible to predation than adult moths, as adults are larger and have a more conspicuous shape. After quantifying predation for 72 h during dawn and dusk using 199 plasticine replicas each of adults and caterpillars, predation on adult replicas was twice that of predation on caterpillar replicas. Furthermore, replicas were six times more likely to be predated on during the day than during the night. Lastly, attacks were made mainly by birds, which carried out 86% of the attacks on adult models and 85% of those on caterpillar models. These data support the hypothesis that predation rates differ across life stages in holometabolous insects. This research lays a foundation for further investigation into how specific differences in morphology across life stages affect predation and survival in holometabolous insects. Full article

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

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15 pages, 1580 KiB

Open AccessArticle

Patterns of Detoxification Enzyme Activities During the Selection of Phortica okadai Resistant to β-Cypermethrin Under Laboratory Conditions

by Juan Zhou, Fang Wu, Yang Luo, Zhenfu Chen, Donghua Long, Hui Liu, Bo Luo, Rong Yan and Lingjun Wang

Insects 2025, 16(4), 346; https://doi.org/10.3390/insects16040346 (registering DOI) - 26 Mar 2025

Abstract

After eight generations of laboratory selection with β-cypermethrin, a P. okadai strain was cultivated that displayed a 10.04-fold increase in resistance (RS) relative to the susceptible strain (SS), with an estimation of heritability (h²) of 0.34. Compared with the SS, [...] Read more.

After eight generations of laboratory selection with β-cypermethrin, a P. okadai strain was cultivated that displayed a 10.04-fold increase in resistance (RS) relative to the susceptible strain (SS), with an estimation of heritability (h²) of 0.34. Compared with the SS, the developmental duration of the eggs was significantly prolonged (p < 0.05); however, the pupal stage duration was shorter, with no statistically significant difference. Moreover, the levels of GSTs, CarEs, and CYP450 activity were notably higher in the RS than in the SS. In addition, the level of CarE and CYP450 activity in the RS was significantly higher in the midgut (MG), fat body (FB), and Malpighian tubules (MTs) compared to the SS; however, the GSTs showed no statistically significant difference in the MTs. These results suggest that P. okadai‘s resistance to β-cypermethrin could be selected rapidly and the decreases in the intrinsic rate of increase (r) observed in the RS are likely due to mutations in the detoxification enzyme genes under the strong selection pressure exerted by β-cypermethrin. The increased activity of GSTs, CarEs, and CYP450 was associated with β-cypermethrin resistance in the RS of P. okadai. The data reported herein provide a foundation for future studies on the mechanisms responsible for β-cypermethrin resistance in P. okadai. Full article

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

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22 pages, 889 KiB

Open AccessReview

CRISPR/Cas Technology in Insect Insecticide Resistance

by Qiuchen Xu, Mingyun Wang, Jiahui Zeng, Hangzhen Sun, Xiaoqi Wei, Hui Jiang, Xuping Shentu and Dan Sun

Insects 2025, 16(4), 345; https://doi.org/10.3390/insects16040345 (registering DOI) - 26 Mar 2025

Abstract

Chemicals and biological insecticides play a crucial role as pest management strategies in modern agriculture and forestry. However, their excessive and unreasonable use inevitably leads to varying degrees of resistance among insect populations, which seriously affects the sustainability of insecticide use. One primary [...] Read more.

Chemicals and biological insecticides play a crucial role as pest management strategies in modern agriculture and forestry. However, their excessive and unreasonable use inevitably leads to varying degrees of resistance among insect populations, which seriously affects the sustainability of insecticide use. One primary reason for this resistance is alterations or mutations in insect gene expression. One class of genes encodes proteins that serve as critical targets for insecticides to exert their toxic effects in insects, while another class of genes encodes proteins involved in the detoxification process of insecticides within insects. Reverse genetics has become a vital research tool for studying the molecular mechanisms underlying changes and mutations in these target genes and their impact on insect resistance. The advent of CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) and the CRISPR-associated gene Cas as gene-editing technologies has significantly advanced our understanding of how insects adapt to and resist insecticides. This article aims to provide a comprehensive and objective review of the progress made using the CRISPR/Cas system in various arthropods within the field of pest control. Full article

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

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19 pages, 2660 KiB

Open AccessArticle

Seasonal Dynamics and Factors Shaping Aquatic Insect Assemblages in Mountain Streams of the Pannonian Lowland Ecoregion

by Viktorija Ergović, Dubravka Čerba, Bojana Tubić, Boris Novaković, Miran Koh and Zlatko Mihaljević

Insects 2025, 16(4), 344; https://doi.org/10.3390/insects16040344 (registering DOI) - 26 Mar 2025

Abstract

This study focused on the aquatic insect orders that serve as biological indicators. Ephemeroptera, Plecoptera, Trichoptera, Coleoptera, and Odonata were studied with their relationships to physical, chemical, hydrological and morphological variables in 14 streams on three Croatian mountains: Papuk, Medvednica and Psunj. From [...] Read more.

This study focused on the aquatic insect orders that serve as biological indicators. Ephemeroptera, Plecoptera, Trichoptera, Coleoptera, and Odonata were studied with their relationships to physical, chemical, hydrological and morphological variables in 14 streams on three Croatian mountains: Papuk, Medvednica and Psunj. From 675 samples collected in three dominant sediment microhabitats (e.g., macrolithal and mesolithal) in each stream, we identified 130 macroinvertebrate taxa. The most abundant group was Ephemeroptera (36 taxa). Aquatic insect assemblages between Papuk and Psunj showed higher similarity due to the geographical proximity of these two mountains, which is expressed as spatial connectivity. In spring, greater variability and diversity of investigated aquatic insects were observed due to the phenology of studied insects. The combination of environmental and morphological properties (e.g., oxygen concentration and substrate type) had the most significant influence on shaping the assemblage of aquatic insects of Psunj, while morphological properties were the most important in shaping aquatic insect assemblages on Papuk (e.g., streambed width) and Medvednica (e.g., elevation). Baetis sp. was the dominant taxon in summer, Protonemura montana in spring, and Leuctra sp. in autumn. Seasonal shifts in environmental conditions lead to functionally unique communities that utilize the pool of available seasonal resources. The dominance of feeding groups varied by season, with scrapers and collector–gatherers being most prevalent in summer, while shredders were dominant in spring. The results on the relationships between environmental characteristics and species richness, functional structure, and distribution of aquatic insects in mountain streams provide important clues for future research and conservation strategies in these vulnerable ecosystems. Full article

(This article belongs to the Special Issue Aquatic Insects: Diversity, Ecology and Evolution)

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15 pages, 421 KiB

Open AccessArticle

Developmental Regulation of Corazonin, Eclosion Hormone, and Bursicon Messages and RNAi Suppression of Corazonin in Adult, Female American Dog Ticks, Dermacentor variabilis

by Anirudh Dhammi, Brooke Bissinger, Loganathan Ponnusamy, Daniel E. Sonenshine and R. Michael Roe

Insects 2025, 16(4), 343; https://doi.org/10.3390/insects16040343 (registering DOI) - 25 Mar 2025

Abstract

The insect molting process is critical to growth and development and is regulated in part by the neuropeptides corazonin, eclosion hormone, and α and β bursicon. We found messages in a synganglion transcriptome from adult, female American dog ticks, Dermacentor variabilis (that do [...] Read more.

The insect molting process is critical to growth and development and is regulated in part by the neuropeptides corazonin, eclosion hormone, and α and β bursicon. We found messages in a synganglion transcriptome from adult, female American dog ticks, Dermacentor variabilis (that do not molt), with a high similarity to the larval insect neuropeptides that control molting. The phylogenetic analysis of the tick putative neuropeptides compared to other arthropods is discussed in detail. The relative gene expression of these peptides was determined by quantitative PCR during the following adult developmental stages: (i) virgin, unfed 0–24 h after entering the adult stage (non-host-seeking), (ii) host-seeking, unfed, and not mated (3 d after emergence), (iii) part-fed (unmated, attached to host; 1st and 3rd day after emergence), (iv) mated (females are part-fed; allowed to mate for ≤1 day, 7th day after emergence), (v) mated repletes (completion of blood feeding but still attached to host), and (vi) post-drop-off (from host) with egg laying starting within 1 d of detachment. Eclosion hormone transcript levels peaked at mating and at drop-off. Bursicon α levels were highest just after molting into adults, with a second smaller peak in replete females. Bursicon β levels were highest (32-fold) post-drop-off. Corazonin message levels peaked in part-feds and were much higher (40-fold) in repletes compared to 0–24 h after emergence. RNAi suppression of the corazonin message by injection in newly molted ticks reduced oviposition and the number of vitellogenic eggs in the ovaries at drop-off but had no apparent effect on host-seeking, partial feeding, mating, feeding to repletion, and drop-off. The possible roles of these transcripts in adult, female tick development are discussed. Full article

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

10 pages, 718 KiB

Open AccessReview

Bored Rotten: Interactions Between the Coffee Berry Borer and Coffee Fruit Rot

by Paul Bayman and Luz M. Serrato-Diaz

Insects 2025, 16(4), 342; https://doi.org/10.3390/insects16040342 (registering DOI) - 25 Mar 2025

Abstract

The coffee berry borer (CBB) is the most destructive pest of coffee worldwide, with damages exceeding $500 M a year and affecting the livelihood of 25 million farmers. Coffee fruit rot (CFR) is described as an anthracnose disease; it can cause up to [...] Read more.

The coffee berry borer (CBB) is the most destructive pest of coffee worldwide, with damages exceeding $500 M a year and affecting the livelihood of 25 million farmers. Coffee fruit rot (CFR) is described as an anthracnose disease; it can cause up to 80% loss of the crop on susceptible cultivars when conditions favor it. These two serious threats to coffee production have been studied separately, but a link between them was not shown until recently. Several recent studies show that CBB damage is associated with a higher incidence of fruit rot; CBBs carry Colletotrichum and Fusarium fungi, also found in rotted fruits, and can transmit disease to coffee fruits as they bore into them. Previous studies on the relationship between CBB and Fusarium did not take into account that Fusarium is involved in coffee fruit rot, so these recent findings shed new light on the relationship. Here we discuss this relationship and its implications, both ecological and practical. Full article

(This article belongs to the Special Issue Biology, Ecology, and Management of the Coffee Berry Borer (Hypothenemus hampei)—2nd Edition)

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15 pages, 248 KiB

Open AccessArticle

Evaluation of Lure and Dispenser Combinations for Halyomorpha halys (Hemiptera: Pentatomidae) Trapping

by Vito Antonio Giannuzzi, Valeria Rossi, Rihem Moujahed, Adriana Poccia, Florinda D’Archivio, Tiziano Rossi Magi, Elena Chierici, Luca Casoli, Gabriele Rondoni and Eric Conti

Insects 2025, 16(4), 341; https://doi.org/10.3390/insects16040341 - 25 Mar 2025

Abstract

The brown marmorated stink bug (BMSB), Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is a polyphagous pest native to East Asia and invasive in many countries. Various approaches have been used to control its spread, including IPM strategies. Monitoring pest populations is the starting point [...] Read more.

The brown marmorated stink bug (BMSB), Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is a polyphagous pest native to East Asia and invasive in many countries. Various approaches have been used to control its spread, including IPM strategies. Monitoring pest populations is the starting point for developing an appropriate control strategy. The most common attractant for H. halys is based on its two-component aggregation pheromone ((3S,6S,7R,10S)-10,11-epoxy-1-bisabolen-3-ol and (3R,6S,7R,10S)-10,11-epoxy-1-bisabolen-3-ol), in combination with the synergist methyl (2E,4E,6Z)-2,4,6-decatrienoate. The aim of this research was to evaluate the most effective combination of the pheromone and the synergist for different types of adjuvants and dispensers, i.e., Blister Pack, Wax Tablet, and Polymers (Non-Biodegradable and Biodegradable Polymers). Field trials were carried out in Northern Italy, during summer and autumn 2023 and 2024. The effectiveness of the different combinations was evaluated on the basis of the number of H. halys individuals caught in sticky traps baited with the different treatments, separated by 50 m each. Individuals actively collected in the surrounding vegetation were also monitored. During the first year, the Non-Biodegradable Polymer performed better than the others. In the second year, H. halys captures were quite similar among the tested dispensers, and all were higher than the control. Captures of non-target stink bugs and other bugs of the Coreidae family were evaluated but, in most cases, were negligible. Under laboratory conditions, the release rate of the chemical compounds differed depending on the type of dispenser. Our results confirm the specificity of the semiochemical lure combination tested towards H. halys and its persistence in the field for at least 12 weeks. The results could be useful for improving the effectiveness of H. halys trapping, as well as for attract-and-kill or push–pull strategies of the pest. Full article

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

28 pages, 390 KiB

Open AccessReview

Patterns and Mechanisms of Niche Partitioning Between Related Parasitoids (Hymenoptera) Sharing the Same Host Species

by Vladimir E. Gokhman

Insects 2025, 16(4), 340; https://doi.org/10.3390/insects16040340 - 25 Mar 2025

Abstract

Related species of parasitoid Hymenoptera often coexist on a certain host, but many details of interactions between these organisms remain unclear. The present review summarizes the main existing concepts and facts and suggests principal patterns and mechanisms that allow for the coexistence of [...] Read more.

Related species of parasitoid Hymenoptera often coexist on a certain host, but many details of interactions between these organisms remain unclear. The present review summarizes the main existing concepts and facts and suggests principal patterns and mechanisms that allow for the coexistence of several members of a particular parasitoid genus at the expense of the same host. Although the successful introduction of exotic parasitic wasps into the existing ecosystems often leads to the competitive displacement of related parasitoids, mere spatial and/or temporal niche partitioning between these insects is also possible. Nevertheless, many cases of coexistence of related wasp species on the same host defy simple explanations since they apparently result from complex interactions between the host and its parasitoids. The main characteristics of the oviposition process, i.e., egg volume, fecundity, and duration of the egg-laying period, are likely to correlate with other basic features of life-history strategies in parasitoid Hymenoptera. Specialist parasitic wasps often aggregate over the host patches, whereas generalists can be randomly distributed, thus reducing the degree of interspecific competition among parasitoids. However, some of the coexisting parasitic wasps, usually the weakest competitors, must also have access to enemy-free space to survive. Full article

(This article belongs to the Special Issue Taxonomy and Biology of Parasitoids and Potential for Their Biological Control)

18 pages, 1963 KiB

Open AccessArticle

Functional and Numerical Responses of Tytthus chinensis (Hemiptera: Miridae) to Sogatella furcifera (Hemiptera: Delphacidae)

by Qian Huang, Liping Long, Suosheng Huang, Biqiu Wu, Cheng Li and Yan Ling

Insects 2025, 16(4), 339; https://doi.org/10.3390/insects16040339 - 24 Mar 2025

Abstract

The predatory function and numerical responses of natural enemy insects are critical for evaluating their biological control potential, particularly in understanding pest suppression mechanisms and ecological adaptability. Here, we examined the predation capacity of Tytthus chinensis Stål (Hemiptera: Miridae) on Sogatella furcifera eggs [...] Read more.

The predatory function and numerical responses of natural enemy insects are critical for evaluating their biological control potential, particularly in understanding pest suppression mechanisms and ecological adaptability. Here, we examined the predation capacity of Tytthus chinensis Stål (Hemiptera: Miridae) on Sogatella furcifera eggs under laboratory conditions (24 ± 1 °C, 12:12 h light:dark photoperiod, 75% humidity). Functional response experiments were conducted at different prey densities (3, 4, 10, 20, and 30 eggs/day), and life table parameters were established to evaluate the effects of prey density on the development, reproduction, and population dynamics of T. chinensis. The daily average predation of nymphs significantly increased with age, and their functional responses fitted the Holling Type II response. In the adult stage, the daily average predation of females was significantly higher than that of males, and males had a higher a/T_h ratio, which reflected sex-specific predation strategies. Prey density significantly influenced survival, reproduction, and population dynamics. The minimum prey density required for population stability was 4 eggs/day, and survival and reproduction rates markedly increased at 10 eggs/day. At 30 eggs/day, females reproduced earlier, and the lifespan of males was shortened. These findings confirm the strong pest control ability of T. chinensis and highlight the critical role of S. furcifera egg density in regulating the population dynamics of T. chinensis. Full article

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

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13 pages, 1520 KiB

Open AccessArticle

Phototaxis Characteristics of Lymantria xylina (Lepidoptera: Erebidae)

by Jifeng Zhang, Baode Wang, Rong Wang, Xiancheng Peng, Junnan Li, Changchun Xu, Yonghong Cui, Mengxia Liu and Feiping Zhang

Insects 2025, 16(4), 338; https://doi.org/10.3390/insects16040338 - 24 Mar 2025

Abstract

Lymantria xylina Swinhoe (Lepidoptera: Erebidae) is considered a potentially internationally invasive forest pest with limited knowledge about its phototactic behavior. This study investigated the phototaxis of L. xylina males and females using various insecticidal lamps in the field. The results showed that all [...] Read more.

Lymantria xylina Swinhoe (Lepidoptera: Erebidae) is considered a potentially internationally invasive forest pest with limited knowledge about its phototactic behavior. This study investigated the phototaxis of L. xylina males and females using various insecticidal lamps in the field. The results showed that all lamps attracted both males and females, but females were captured in a very low numbers, with a female-to-male ratio of 1:322. The insecticidal lamp with a peak wavelength of 363 nm was most effective for male trapping. Males exhibited a distinct light-trapping rhythm, peaking around midnight (23:00–0:00), with 29.5% capture, while females were most active at dusk (19:00–20:00), with 44.4% capture. Light-trapped females were smaller and lighter than indoor-emerged females and had lower egg-carrying capacity. Females, when laying eggs, did not exhibit phototactic behavior. Only 14.6% of non-ovipositing females showed phototactic behavior, and only 0.6% flew directly toward the lamp. These findings suggest that while non-ovipositing females can exhibit phototaxis, only a small proportion will, potentially reducing the risk of long-distance dispersal of L. xylina via ocean-going freighters. The results showed that the non-ovipositing females could fly under phototaxis, but their phototaxis was limited. This study provides a basis for the risk assessment of the long-distance dispersal of L. xylina via ocean-going freighters through female moth phototactic flight. Full article

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

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14 pages, 5200 KiB

Open AccessArticle

Comparative Transcriptome Analysis Reveals the Effects of a High-Protein Diet on Silkworm Midgut

by Xinyi Chen, Jiahao Li, Yuxi Shan, Qiaoling Wang, Pingzhen Xu, Heying Qian and Yangchun Wu

Insects 2025, 16(4), 337; https://doi.org/10.3390/insects16040337 - 24 Mar 2025

Abstract

The silkworm is a species within the order Lepidoptera and an economic insect. The nutrients are obtained from the leaf and utilized by the silkworm larvae for body growth, development, and cocoon formation. Protein plays a significant functional role in the diet of [...] Read more.

The silkworm is a species within the order Lepidoptera and an economic insect. The nutrients are obtained from the leaf and utilized by the silkworm larvae for body growth, development, and cocoon formation. Protein plays a significant functional role in the diet of silkworms. To investigate the impact of the high-protein diet (HPD 6%) on silkworm growth and development, transcriptomic analysis was conducted on the silkworm midgut, and 1724 differentially expressed genes (DEGs) were identified, comprising 803 up-regulated genes and 921 down-regulated genes. The up-regulated genes exhibited the majority pathway of mitochondrial oxidative phosphorylation, ribosome, and ribosome biogenesis in eukaryotes. The down-regulated genes of DEGs were mostly annotated in ABC transporters, lysosome, endocytosis, and sphingolipid metabolism pathways. The comprehensive analysis of DEGs indicated that substantial modifications were observed in various pathways associated with crucial biological processes. HPD 6% decreased oxidative stress and increased mitochondrial activity, ribosomal activity, and DNA repair capacity. Additionally, the ATP levels were increased in the midgut, malpighian tubule, middle silk gland, and posterior silk gland of the HPD 6% group. Moreover, the activities of SOD and NADH were enhanced in the midgut of the HPD 6% group. Our findings provide valuable insights into the wide-ranging effects of an HPD treatment in insects such as silkworms. Full article

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

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18 pages, 6082 KiB

Open AccessFeature PaperArticle

The Delineation of Management Zones of the Halyomorpha halys (Hemiptera: Pentatomidae) Population Based on Its Spatiotemporal Distribution for Precision Agriculture Purposes

by Vasileios Liakos, Eleni I. Koutsogeorgiou, Sofia Charouli, Ioannis E. Navrozidis, Georgios Proias and Stefanos S. Andreadis

Insects 2025, 16(4), 336; https://doi.org/10.3390/insects16040336 - 22 Mar 2025

Abstract

Precision Agriculture is an agricultural management strategy that aims to increase farmers’ profit, maximize crop productivity and sustainability, and protect the environment by applying inputs in optimum rates based on plant needs. The delineation of site-specific management zones is a crucial step at [...] Read more.

Precision Agriculture is an agricultural management strategy that aims to increase farmers’ profit, maximize crop productivity and sustainability, and protect the environment by applying inputs in optimum rates based on plant needs. The delineation of site-specific management zones is a crucial step at the application of Precision Agriculture. However, the procedure of delineating management zones for pest management is difficult since pest populations are dynamic and change spatially and temporally throughout a growing season. The objectives of this work is to study kiwi canopy characteristics, to correlate them with Halyomorpha halys (Hemiptera: Pentatomidae) populations and delineate management zones for pesticide applications in variable rates. To achieve this, four kiwi orchards in total were selected in the regions of Pieria and Imathia in Greece. Τen traps were installed from early May to late October within each selected kiwi orchard: two types of traps at every side of the orchards and the center. The installed traps were examined weekly, and the number of the captured H. halys was recorded. During the same days, sentinel satellite images were analyzed to calculate the indices: NDVI (Normalized Difference Vegetation Index) and NDWI (Normalized Difference Water Index). The collected data were combined in a GIS software to delineate management zones using a K means algorithm and unsupervised classification. The results of this three-year study showed population variability within the kiwi orchards since the population of H. halys was higher in field regions where NDVI and NDWI values were high. The delineation of management zones revealed that there are spatio-temporal stable zones in each field where there is high, medium, and low risk to develop H. halys populations. The benefits of the proposed strategy are multiple since it is expected that farmers will be able to reduce the production expenses of kiwifruits and environmental protection while increasing profit. Full article

(This article belongs to the Collection Hemiptera: Ecology, Physiology, and Economic Importance)

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