Insects

17 pages, 2323 KiB

Open AccessArticle

Simultaneous Silencing of Gut Nucleases and a Vital Target Gene by Adult dsRNA Feeding Enhances RNAi Efficiency and Mortality in Ceratitis capitata

by Gennaro Volpe, Sarah Maria Mazzucchiello, Noemi Rosati, Francesca Lucibelli, Marianna Varone, Dora Baccaro, Ilaria Mattei, Ilaria Di Lelio, Andrea Becchimanzi, Ennio Giordano, Marco Salvemini, Serena Aceto, Francesco Pennacchio and Giuseppe Saccone

Insects 2024, 15(9), 717; https://doi.org/10.3390/insects15090717 - 19 Sep 2024

Abstract

Ceratitis capitata, known as the Mediterranean fruit fly (Medfly), is a major dipteran pest significantly impacting fruit and vegetable farming. Currently, its control heavily relies mainly on chemical insecticides, which pose health risks and have effects on pollinators. A more [...] Read more.

Ceratitis capitata, known as the Mediterranean fruit fly (Medfly), is a major dipteran pest significantly impacting fruit and vegetable farming. Currently, its control heavily relies mainly on chemical insecticides, which pose health risks and have effects on pollinators. A more sustainable and species-specific alternative strategy may be based on double-stranded RNA (dsRNA) delivery through feeding to disrupt essential functions in pest insects, which is poorly reported in dipteran species. Previous reports in Orthoptera and Coleoptera species suggested that dsRNA degradation by specific nucleases in the intestinal lumen is among the major obstacles to feeding-mediated RNAi in insects. In our study, we experimented with three-day adult feeding using a combination of dsRNA molecules that target the expression of the ATPase vital gene and two intestinal dsRNA nucleases. These dsRNA molecules were recently tested separately in two Tephritidae species, showing limited effectiveness. In contrast, by simultaneously feeding dsRNA against the CcVha68-1, CcdsRNase1, and CcdsRNase2 genes, we observed 79% mortality over seven days, which was associated with a decrease in mRNA levels of the three targeted genes. As expected, we also observed a reduction in dsRNA degradation following RNAi against nucleases. This research illustrates the potential of utilizing molecules as pesticides to achieve mortality rates in Medfly adults by targeting crucial genes and intestinal nucleases. Furthermore, it underscores the importance of exploring RNAi-based approaches for pest management. Full article

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

► Show Figures

Graphical abstract

24 pages, 17126 KiB

Open AccessArticle

Characteristics of a Spray-Dried Porcine Blood Meal for Aedes aegypti Mosquitoes

by Alexander R. Weaver, Nagarajan R. Rajagopal, Roberto M. Pereira, Philip G. Koehler, Andrew J. MacIntosh, Rebecca W. Baldwin and Christopher D. Batich

Insects 2024, 15(9), 716; https://doi.org/10.3390/insects15090716 - 19 Sep 2024

Abstract

Research into mosquito-borne illnesses faces hurdles because feeding fresh animal blood to rear female mosquitoes presents logistical, economic, and safety challenges. In this study, a shelf-stable additive (spray-dried porcine blood; SDPB) hypothesized to supply accessible hemoglobin was evaluated within an alternative meal (AM) [...] Read more.

Research into mosquito-borne illnesses faces hurdles because feeding fresh animal blood to rear female mosquitoes presents logistical, economic, and safety challenges. In this study, a shelf-stable additive (spray-dried porcine blood; SDPB) hypothesized to supply accessible hemoglobin was evaluated within an alternative meal (AM) containing whey powder and PBS for rearing the yellow fever mosquito Aedes aegypti. LC–MS/MS proteomics, microbial assays, and particle reduction techniques confirmed and characterized the functionality of hemoglobin in SDPB, while engorgement, fecundity, egg viability, and meal stability bioassays assessed AM performance. Chemical assays supported hemoglobin as the phagostimulant in SDPB with aggregates partially solubilized in the AM that can be more accessible via particle reduction. Unpaired two-tailed t-tests indicate that the AM stimulates oogenesis (t₁₁ = 13.6, p = 0.003) and is stable under ambient (1+ y; t₁₂ = 0.576, p = 0.575) and aqueous (14 d; t₁₂ = 0.515, p = 0.639) conditions without decreasing fecundity. Egg hatch rates for the ninth generation of AM-reared Ae. aegypti were 50–70+%. With further development, this meal may serve as a platform for mass rearing or studying effects of nutritional additives on mosquito fitness due to its low cost and stability. Future work may examine tuning spray drying parameters and resulting impacts on hemoglobin agglomeration and feeding. Full article

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

► Show Figures

Figure 1

21 pages, 3473 KiB

Open AccessArticle

Development of Tools to Understand the Relationship between Good Management Practices and Nest Losses in Meliponiculture: A Pilot Study in Latin American Countries

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

Insects 2024, 15(9), 715; https://doi.org/10.3390/insects15090715 - 19 Sep 2024

Abstract

Insect pollination services amount to USD 235–577 billion. Seventy five percent of agricultural production for human consumption depends on pollination, mainly by bees. A decline in pollinators, including Meliponini tribe bees, will impact the economy, food security, human health, and ecosystem stability, especially [...] Read more.

Insect pollination services amount to USD 235–577 billion. Seventy five percent of agricultural production for human consumption depends on pollination, mainly by bees. A decline in pollinators, including Meliponini tribe bees, will impact the economy, food security, human health, and ecosystem stability, especially in tropical forests where stingless bees are the main pollinators. The objective of this survey was to understand the relationship between good management practices and nest losses in meliponiculture, encompassing biosecurity and conservation criteria. A 36-question survey was organized and spread. We received 92 responses, representing 4548 managed nests. The primary motivation for engaging in meliponiculture was biodiversity conservation (92%). More than 50% of the questions on biosecurity were answered as “applied”. Hand washing before any activity with bees was the main rule, followed by material sterilization and personal protective equipment use. The annual mortality rate of stingless bee nests was estimated at 15%. Nest invaders (72%) and nearby sources of pollution (60%) were identified as the main potential causes of nest losses. From a general perspective, meliponiculture practices continue to expand remarkably. The implementation of effective nest management strategies is associated with a reduction in nest losses. It is important to consider One Health’s perspective to ensure optimal management practices. Full article

(This article belongs to the Collection Impact of Environmental Factors and Management Practices on Bee Health)

► Show Figures

Figure 1

15 pages, 7857 KiB

Open AccessArticle

Synergistic Larvicidal and Pupicidal Toxicity and the Morphological Impact of the Dengue Vector (Aedes aegypti) Induced by Geranial and trans-Cinnamaldehyde

by Sirawut Sittichok, Hataichanok Passara, Jirisuda Sinthusiri, Tanapoom Moungthipmalai, Cheepchanok Puwanard, Kouhei Murata and Mayura Soonwera

Insects 2024, 15(9), 714; https://doi.org/10.3390/insects15090714 - 18 Sep 2024

Abstract

Monoterpenes are effective and eco-friendly alternatives to conventional chemical larvicides. We tested single and binary mixtures of monoterpenes—geranial and trans-cinnamaldehyde—for their larvicidal and pupicidal activities against Aedes aegypti L. and for non-target toxicity on guppies (Poecilia reticulata Peters), using 1% ( [...] Read more.

Monoterpenes are effective and eco-friendly alternatives to conventional chemical larvicides. We tested single and binary mixtures of monoterpenes—geranial and trans-cinnamaldehyde—for their larvicidal and pupicidal activities against Aedes aegypti L. and for non-target toxicity on guppies (Poecilia reticulata Peters), using 1% (w/w) temephos as a reference. Geranial and trans-cinnamaldehyde at 250 ppm showed stronger larvicidal and pupicidal activities with a 100% mortality rate and an LT₅₀ ranging from 0.3 to 0.6 h. All combinations were strongly synergistic against larvae and pupae compared to single formulations, with an increased mortality value (IMV) of 6% to 93%. The combination of geranial + trans-cinnamaldehyde (1:1) at 200 ppm showed the highest impact, with an IMV of 93%. The strongest larvicidal and pupicidal activities, a 100% mortality rate, and an LT₅₀ of 0.2 h were achieved by geranial + trans-cinnamaldehyde (1:1) 500 ppm. They were thirty times more effective than a 1% temephos solution (LT₅₀ ranging from 6.7 to 96 h) and caused obviously shriveled cuticles and a swollen respiratory system. All single and binary mixtures were not toxic to the guppies. Thus, the combination of geranial + trans-cinnamaldehyde has great potential as a safe insecticide for controlling mosquito larvae and pupae. Full article

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

► Show Figures

Figure 1

17 pages, 7479 KiB

Open AccessArticle

Influences of Salt Stress on Cotton Metabolism and Its Consequential Effects on the Development and Fecundity of Aphis gossypii Glover

by Wangquan Jiao, Bingmei Song, Hongsheng Pan and Xiaoning Liu

Insects 2024, 15(9), 713; https://doi.org/10.3390/insects15090713 - 18 Sep 2024

Abstract

The degree of global soil salinization is gradually deepening, which will inevitably affect agricultural ecology. It has been found that salt stress induces the resistance of host plants to phytophagous pests. However, little is known about the effects of salt-stressed cotton plants on [...] Read more.

The degree of global soil salinization is gradually deepening, which will inevitably affect agricultural ecology. It has been found that salt stress induces the resistance of host plants to phytophagous pests. However, little is known about the effects of salt-stressed cotton plants on the fitness of cotton aphids (Aphis gossypii Glover). In this study, we investigated the differences between cotton metabolomes under mild (75 mM NaCl) and moderate (150 mM NaCl) salinity conditions and their effects on the fitness of cotton aphids. The results showed that 49 metabolites exhibited significant upregulation, while 86 metabolites were downregulated, with the increasing NaCl concentration. The duration of nymphal aphids under 150 mM NaCl significantly extended to 6.31 days when compared with the control (0 mM NaCl, 4.10 days). Meanwhile, the longevity of adult aphids decreased significantly under 75 and 150 mM NaCl, with an average of 10.38 days (0 mM NaCl) reduced to 8.55 and 4.89 days, respectively. Additionally, the total reproduction number of single females decreased from 31.31 (0 mM NaCl) to 21.13 (75 mM NaCl) and 10.75 (150 mM NaCl), whereas the survival rate of aphids decreased from 81.25% (0 mM NaCl) to 56.25% (75 mM NaCl) and 34.38% (150 mM NaCl) on the 12th day. These results support the hypothesis that plants growing under salt stress are better defended against herbivores. Furthermore, 49 differential metabolites were found to be negatively correlated with the longevity and fecundity of adult aphids, while 86 different metabolites showed the opposite trend. These results provide insights into the occurrence and control of cotton aphids amidst the escalating issue of secondary salinization. Full article

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

► Show Figures

Figure 1

15 pages, 2091 KiB

Open AccessArticle

High-Throughput Screening System Evaluation of Andrographis paniculata (Burm.f.) Extracts and Their Fractions against Mosquito Vectors

by Patcharawan Sirisopa, Theerachart Leepasert, Thitinun Karpkird, Jirod Nararak, Kanutcharee Thanispong, Alex Ahebwa and Theeraphap Chareonviriyaphap

Insects 2024, 15(9), 712; https://doi.org/10.3390/insects15090712 - 18 Sep 2024

Abstract

Infectious diseases that cause illness and/or death in humans can be contracted from mosquito bites. A viable and alternate method of personal protection that can lower the danger of human exposure to mosquito-borne diseases is the use of plant-based repellents. Using a high-throughput [...] Read more.

Infectious diseases that cause illness and/or death in humans can be contracted from mosquito bites. A viable and alternate method of personal protection that can lower the danger of human exposure to mosquito-borne diseases is the use of plant-based repellents. Using a high-throughput screening system, the current work examined the toxicity, contact irritancy, and spatial repellency of Andrographis paniculata crude extract and its fractions against Aedes aegypti, Anopheles minimus, and An. dirus. Five fractions (i.e., F1, F2, F3, F4, and F5) were separated from the crude extract by column and thin layer chromatography and analyzed using high-performance liquid chromatography and mass spectrometry. The major active compounds identified from F3 and F5 were 4-deoxy-11,12-didehydroandrographolide and andrographolide. Three concentrations (1.0, 2.5, and 5.0%) for each of the crude extracts and the five fractions were individually impregnated on nylon netting strips and evaluated against the three mosquito species. Results showed that the highest contact irritancy was elicited by the crude extract at 5% concentration against Ae. aegypti (43.70% escaped). Results of the spatial activity index (SAI) showed that fractions F3 and F5 at 2.5% demonstrated the strongest repellency against Ae. aegypti (SAI = 0.84) and An. minimus (SAI = 0.83), respectively. Both the crude extract and its components did not cause any knockdown or mortality. These findings suggest that fractionation of A. paniculata extracts is valuable in assessing their spatial repellent efficacy against mosquitoes. Fractions F3 and F5 hold promise as natural mosquito repellents and could contribute to developing effective mosquito control strategies. Full article

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

► Show Figures

Figure 1

27 pages, 2254 KiB

Open AccessReview

Research Status of Sarcosaprophagous Beetles as Forensic Indicators

by Shipeng Shao, Siqi Liu, Liangliang Li, Gengwang Hu, Yingna Zhang and Yu Wang

Insects 2024, 15(9), 711; https://doi.org/10.3390/insects15090711 - 17 Sep 2024

Abstract

In forensic entomology, research focused on sarcosaprophagous flies, but the sarcosaprophagous beetles, as important “forensic indicator species” of late-stage PMI in cadaver decomposition, received less attention. To increase attention on, and use and understanding of, sarcosaprophagous beetles in forensic entomology, this paper presents [...] Read more.

In forensic entomology, research focused on sarcosaprophagous flies, but the sarcosaprophagous beetles, as important “forensic indicator species” of late-stage PMI in cadaver decomposition, received less attention. To increase attention on, and use and understanding of, sarcosaprophagous beetles in forensic entomology, this paper presents a bibliometric analysis of the available relevant literature. The occurrence frequency of beetle families and species from succession studies, actual cases, and experiments were calculated and illustrated using graphs. As a result, a total of 14 families and 1077 species associated with carcasses were collected, with Staphylinidae being the most frequently recorded among the families, and Necrobia rufipes (Fabricius, 1781) (Coleoptera: Cleridae) being the most frequently recorded species. In addition, a brief introduction of the cadaver-related beetles of each family is given, and research on the species identification of the immature stages, age estimation of the immature stages, and estimation of the arrival time of sarcosaprophagous beetles are discussed and prospected. This work will aid in the increased use of sarcosaprophagous beetles in forensic science practice in the future. Full article

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

► Show Figures

Figure 1

18 pages, 3456 KiB

Open AccessArticle

A Comparative Analysis of Different Xenorhabdus Strains Reveals a Virulent Factor, Cyclic Pro-Phe, Using a Differential Expression Profile Analysis of Non-Ribosomal Peptide Synthetases

by Gahyeon Jin, Falguni Khan and Yonggyun Kim

Insects 2024, 15(9), 710; https://doi.org/10.3390/insects15090710 - 17 Sep 2024

Abstract

Entomopathogenic bacteria, classified into the genus Xenorhabdus, exhibit a dual lifestyle as mutualistic symbionts to Steinernema nematodes and as pathogens to a broad range of insects. Bacterial virulence depends on toxin proteins that induce toxemia and various immunosuppressive secondary metabolites that cause [...] Read more.

Entomopathogenic bacteria, classified into the genus Xenorhabdus, exhibit a dual lifestyle as mutualistic symbionts to Steinernema nematodes and as pathogens to a broad range of insects. Bacterial virulence depends on toxin proteins that induce toxemia and various immunosuppressive secondary metabolites that cause septicemia. Particularly, the immunosuppressive properties of Xenorhabdus bacteria determine the variability of their insecticidal activities. This study explored the role of peptide metabolites in virulence and its variation among six bacterial strains across three species: X. nematophila, X. bovienii, and X. hominickii. Initially, their virulence significantly varied against a susceptible lepidopteran host, Maruca vitrata, but showed less variation against a tolerant coleopteran host, Tenebrio molitor, with high median lethal bacterial doses. In M. vitrata, virulence was strongly correlated with bacterial growth rate and inhibitory activity against phospholipase A₂. Secondly, the six strains differed in the compositions of their secreted secondary metabolites, analyzed by GC-MS following ethyl acetate extraction. Notably, there was significant variation in the production of di- or tetra-peptides. Highly virulent strains commonly produced the cyclic Pro-Phe (cPF). Thirdly, the expression of non-ribosomal peptide synthetase (NRPS) genes varied greatly among the strains. NRPS genes were minimally expressed in the tolerant T. molitor and highly expressed in the susceptible M. vitrata. In M. vitrata, specific NRPS genes were markedly expressed in the virulent strains. Finally, cPF demonstrated potent immunosuppressive activity against the cellular and humoral responses of M. vitrata. The addition of cPF significantly enhanced the virulence against the tolerant T. molitor. These findings suggest that immunosuppression is necessary for the pathogenicity of Xenorhabdus bacteria, wherein NRPS products play a critical role in suppressing immune-associated factors in target insects. Full article

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

► Show Figures

Figure 1

15 pages, 10492 KiB

Open AccessArticle

The Spread of Lone Star Ticks (Amblyomma americanum) and Persistence of Blacklegged Ticks (Ixodes scapularis) on a Coastal Island in Massachusetts, USA

by Richard W. Johnson, Patrick Roden-Reynolds, Allison A. Snow and Stephen M. Rich

Insects 2024, 15(9), 709; https://doi.org/10.3390/insects15090709 - 17 Sep 2024

Abstract

In the northeastern USA, the distribution of lone star ticks (Amblyomma americanum) has expanded northward in recent decades, overlapping with the range of blacklegged ticks (Ixodes scapularis). Blacklegged ticks carry pathogens for diseases such as Lyme, babesiosis, and anaplasmosis, [...] Read more.

In the northeastern USA, the distribution of lone star ticks (Amblyomma americanum) has expanded northward in recent decades, overlapping with the range of blacklegged ticks (Ixodes scapularis). Blacklegged ticks carry pathogens for diseases such as Lyme, babesiosis, and anaplasmosis, while bites from lone star ticks cause other diseases and the alpha-gal syndrome allergy. Lone star ticks can become so abundant that they are perceived as more of a public health threat than blacklegged ticks. Using the island of Martha’s Vineyard, Massachusetts, as a case study, we analyzed data from a total of 1265 yard surveys from 2011 to 2024 to document lone star tick presence and subsequent expansion from two peripheral areas, Chappaquiddick and Aquinnah, to all six towns. The timing of lone star tick expansion on Martha’s Vineyard closely matched an increase in tick submissions to a pathogen testing center. At Chappaquiddick, drag sampling carried out in June 2023 and 2024 showed that both tick species were most common at wooded sites, where blacklegged nymphs were somewhat more abundant than lone star nymphs. However, lone star ticks occurred in a wider range of natural and peridomestic habitats than blacklegged nymphs, making them far more challenging for people to avoid and manage. Full article

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

► Show Figures

Figure 1

14 pages, 4718 KiB

Open AccessArticle

Global Distribution Prediction of Cyrtotrachelus buqueti Guer (Coleoptera: Curculionidae) Insights from the Optimised MaxEnt Model

by Yaqin Peng, Junyi Yang, Danping Xu and Zhihang Zhuo

Insects 2024, 15(9), 708; https://doi.org/10.3390/insects15090708 - 17 Sep 2024

Abstract

Cyrtotrachelus buqueti Guer is a major pest affecting bamboo forests economically, causing significant damage to bamboo forests in Sichuan Province, China. To understand how C. buqueti responds to future climate conditions, an optimized Maximum Entropy Model (Maxent) was used to simulate the potential [...] Read more.

Cyrtotrachelus buqueti Guer is a major pest affecting bamboo forests economically, causing significant damage to bamboo forests in Sichuan Province, China. To understand how C. buqueti responds to future climate conditions, an optimized Maximum Entropy Model (Maxent) was used to simulate the potential global distribution patterns of C. buqueti under current climate conditions and three different future climate scenarios and to analyze the dominant factors influencing its distribution. The results indicate that Bio18 (precipitation of the warmest quarter), Bio04 (temperature seasonality), Bio06 (minimum temperature of the coldest month), and Bio02 (mean diurnal temperature range) are the main environmental factors affecting the distribution of this species. The global area of high-suitability habitats for C. buqueti is 9.00 × 10⁴ km², primarily distributed in China. Under three different future climate scenarios, there are varying degrees of expansion in both the total suitable habitat and the medium-suitability areas for C. buqueti. Under the SSP5-8.5 scenario, the medium-suitability area of the species increases the most, reaching 9.83 × 10⁴ km². Additionally, these findings can serve as a reference for developing and implementing control strategies, assisting relevant authorities in more effectively managing and controlling this pest, and mitigating its potential threats to bamboo forest ecosystems and economies. Full article

(This article belongs to the Special Issue Insect Dynamics: Modeling in Insect Pest Management)

► Show Figures

Figure 1

22 pages, 3320 KiB

Open AccessArticle

Bioactive Insecticides from Chemometric Diverse Ant-Associated Symbionts Streptomyces novaecaesareae and Streptomyces nojiriensis against the Fall Armyworm Larvae

by Cecília Beatriz Nascimento Lima, Mariana Montini Joly, Luiz Alberto Beraldo Moraes and Fernando Luís Cônsoli

Insects 2024, 15(9), 707; https://doi.org/10.3390/insects15090707 - 17 Sep 2024

Abstract

The Streptomyces genus has long been recognized as a prolific and valuable source of diverse secondary metabolites. These metabolites contribute significantly to the intricate chemical diversity exhibited by Streptomyces, making them an indispensable reservoir for drug discovery, agricultural applications, and industrial processes. [...] Read more.

The Streptomyces genus has long been recognized as a prolific and valuable source of diverse secondary metabolites. These metabolites contribute significantly to the intricate chemical diversity exhibited by Streptomyces, making them an indispensable reservoir for drug discovery, agricultural applications, and industrial processes. Exploiting the potential of these natural compounds holds the promise of ushering in a new era in insect pest management, reducing reliance on synthetic chemicals and fostering ecologically sustainable solutions. This study dives into the realm of chemo diversity within isolates of Streptomyces nojiriensis and Streptomyces novaecaesareae, with a specific focus on the production of insecticidal compounds. We explored chromatographic techniques for the identification and isolation of insecticidal compounds, and two bioactive compounds were identified in extracts of S. novaecaesareae. Valinomycin was identified from hexanic extracts of strain Asp59, while naphthomycin from ethyl acetate extracts of strain Asp58. These compounds showed insecticidal activity against first instars of Spodoptera frugiperda (Asp59: LC₅₀ = 10.82 µg/µL, LC₉₀ = 26.25 µg/µL; Asp58: LC₅₀ = 15.05 µg/µL, LC₉₀ = 38.84 µg/µL). Notably, this is the first report of naphthomycin as an insecticidal compound. The present study suggests that valinomycin and naphthomycin may be a novel biological source for the control of Spodoptera frugiperda in early stages. Full article

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

► Show Figures

Figure 1

19 pages, 987 KiB

Open AccessReview

The Biology, Impact, and Management of Xyleborus Beetles: A Comprehensive Review

by Sared Helena Rodríguez-Becerra, Rafael Vázquez-Rivera, Karla Irazú Ventura-Hernández, Tushar Janardan Pawar and José Luis Olivares-Romero

Insects 2024, 15(9), 706; https://doi.org/10.3390/insects15090706 - 17 Sep 2024

Abstract

Xyleborus beetles, a diverse group of ambrosia beetles, present challenges to forestry and agriculture due to their damaging burrowing behavior and symbiotic relationships with fungi. This review synthesizes current knowledge on the biology, ecology, and management of Xyleborus. We explore the beetles’ [...] Read more.

Xyleborus beetles, a diverse group of ambrosia beetles, present challenges to forestry and agriculture due to their damaging burrowing behavior and symbiotic relationships with fungi. This review synthesizes current knowledge on the biology, ecology, and management of Xyleborus. We explore the beetles’ life cycle, reproductive strategies, habitat preferences, and feeding habits, emphasizing their ecological and economic impacts. Control and management strategies, including preventive measures, chemical and biological control, and integrated pest management (IPM), are critically evaluated. Recent advances in molecular genetics and behavioral studies offer insights into genetic diversity, population structure, and host selection mechanisms. Despite progress, managing Xyleborus effectively remains challenging. This review identifies future research needs and highlights innovative control methods, such as biopesticides and pheromone-based trapping systems. Full article

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

► Show Figures

Figure 1

15 pages, 975 KiB

Open AccessArticle

Monitoring and Detection of Insecticide Resistance in Spodoptera frugiperda (Lepidoptera: Noctuidae): Evidence for Field-Evolved Resistance in Egypt

by Moataz A. M. Moustafa, Nourhan A. El-Said, Nawal AbdulAziz Alfuhaid, Fatma M. A. Abo-Elinin, Radwa M. B. Mohamed and Ahmed A. A. Aioub

Insects 2024, 15(9), 705; https://doi.org/10.3390/insects15090705 - 16 Sep 2024

Abstract

Spodoptera frugiperda (J.E. Smith) (Noctuidae: Lepidoptera) is a notable insect pest that invades major cereal crops, causing significant damage and loss. Resistances of 2nd instar larvae of two Egyptian field populations of S. frugiperda, collected from the Fayoum and Giza governments, were [...] Read more.

Spodoptera frugiperda (J.E. Smith) (Noctuidae: Lepidoptera) is a notable insect pest that invades major cereal crops, causing significant damage and loss. Resistances of 2nd instar larvae of two Egyptian field populations of S. frugiperda, collected from the Fayoum and Giza governments, were measured against eight insecticides, including traditional insecticides (profenofos and cypermethrin), bio-insecticides (emamectin benzoate, spinosad, and Bacillus thuringiensis), and insect growth regulators (IGRs) (lufenuron, diflubenzuron, and methoxyfenozide). In addition, the synergistic effects of three synergists (Piperonyl butoxide (PBO), diethyl maleate (DEM), and triphenyl phosphate (TPP) were assessed, and the activities of detoxification enzymes (acetylcholine esterase (AChE), cytochrome P-450 (CYP-450), carboxylesterase (CarE), and glutathione-s-transferase (GST) were also determined. Resistance surveillance revealed that the Fayoum field population showed moderate resistance to cypermethrin (RR = 5.75-fold), followed by spinosad (RR = 2.62-fold), and lufenuron (2.01-fold). On the other hand, the Giza population exhibited significant resistance to cypermethrin only (RR = 3.65-fold). Our results revealed that emamectin benzoate was the most effective insecticide, with an LC₅₀ value of 0.003 mg/L for the Fayoum population and 0.001 mg/L for the Giza population, compared to the susceptible strain (0.005 mg/L). Among the biological insecticides, Bacillus thuringiensis was the least toxic insecticide of all the tested strains. Synergism assays indicated that DEM and TPP had the most synergistic effect on spinosad (SR = 8.00-fold for both), followed by PBO (SR = 5.71-fold) for the Fayoum population, compared with spinosad alone. The assay of detoxification enzymes showed that GST activity significantly (p < 0.05) increased in the two field strains compared to the susceptible strain. However, no significant changes were observed among the tested strains in CYP-450, CarE, or AChE. The findings of this study provide substantial insights into tracking and managing the development of insecticide resistance in S. frugiperda in Egypt. Full article

(This article belongs to the Special Issue Chemical Toxicology and Insecticide Resistance on Insect Pests)

► Show Figures

Graphical abstract

13 pages, 1044 KiB

Open AccessArticle

Effect of Co-Diet Supplementation on Biodegradation of Polyethylene by Galleria mellonella L. (Lepidoptera: Pyralidae)

by Areej Mahfooz, Muhammad Yasin, Mirza Abdul Qayyum, Asim Abbasi, Abeer Hashem, Khalid F. Almutairi, Elsayed Fathi Abd_Allah, Muhammad Farhan, Muhammad Anjum Aqueel and Mishal Subhan

Insects 2024, 15(9), 704; https://doi.org/10.3390/insects15090704 - 16 Sep 2024

Abstract

Pollution coming from plastic polymers, particularly polyethylene (PE), poses a serious threat to both humans and animals. The biodegradation of plastics facilitated by insects is a crucial and eco-friendly approach that can be employed to combat this global concern. Recently, the larvae of [...] Read more.

Pollution coming from plastic polymers, particularly polyethylene (PE), poses a serious threat to both humans and animals. The biodegradation of plastics facilitated by insects is a crucial and eco-friendly approach that can be employed to combat this global concern. Recently, the larvae of the greater wax moth Galleria mellonella (L.) have been recognized as avid ‘plastivores’. The current study was aimed at evaluating the feeding efficiency of G. mellonella larvae on PEs of various densities with a co-diet supplementation of wheat germ + honey and beeswax. The results reveal that maximum PE consumption (9.98 ± 1.25 mg) was recorded in the case of 1.0 mm thick PE after a 24 h interval; however, the same scenario also achieved the greatest reduction in larval weight (27.79 ± 2.02 mg). A significant reduction in PE mass (5.87 ± 1.44 mg) was also observed in 1.0 mm PE when fed beeswax; however, the larvae experienced minimal weight loss (9.59 ± 3.81 mg). The larvae exhibited a higher PE consumption in 1.0 mm PE, indicating that the lower the density of PE, the greater the consumed area. Moreover, the biodegradation levels were notably higher within the 24 h interval. In conclusion, these findings suggest that the density of PEs and the supplementation of the co-diet have an impact on PE biodegradation. Additionally, the utilization of G. mellonella for the biodegradation of PE proves effective when combined with beeswax, resulting in minimal weight loss of the larvae. Our findings offer initial insights into how Galleria mellonella larvae biodegrade polyethylene (PE) of four different densities, along with co-diet supplementation. This approach helps us evaluate how varying densities affect degradation rates and provides a better understanding of the larvae’s capabilities. Additionally, our observations at three specific time intervals (24, 48, and 72 h) allow us to identify the time required for achieving degradation rates. Through examining these time points, our method offers valuable insights into the initial phases of plastic consumption and biodegradation. Full article

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

► Show Figures

Figure 1

14 pages, 4957 KiB

Open AccessArticle

Toxicity Evaluation of Potassium Sorbate In Vivo with Drosophila Melanogaster

by Xubo Zhang, Qian Zhang, Xiaoxuan Song, Wanchen Yang, Andi Cheng, Jianzhen Zhang and Wei Dong

Insects 2024, 15(9), 703; https://doi.org/10.3390/insects15090703 - 14 Sep 2024

Abstract

Potassium sorbate (PS) is a preservative widely used in the food, pharmaceutical, and cosmetics industries. Improper and careless use of PS can lead to various health issues and potential environmental problems. Drosophila is capable of making rapid and sensitive responses to stress or [...] Read more.

Potassium sorbate (PS) is a preservative widely used in the food, pharmaceutical, and cosmetics industries. Improper and careless use of PS can lead to various health issues and potential environmental problems. Drosophila is capable of making rapid and sensitive responses to stress or other stimuli. Here we utilized Drosophila as a model organism to evaluate the potential toxicity of PS. Our study revealed that PS ingestion reduced the lifespan and fecundity of Drosophila. In addition, excessive PS ingestion led to cell apoptosis and ROS accumulation in the midgut. Furthermore, PS intake also enhanced the mitophagy of midgut cells. Strikingly, PS affected the cell differentiation progression as well, leading to the production of more enteroendocrine (EE) cells. We further demonstrated that the expression of notch (N), a vital player in intestinal stem cell (ISC) differentiation, was down-regulated in the midgut. This indicates that the differentiation progression was affected potentially by repressing the N expression. Full article

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

► Show Figures

Figure 1

13 pages, 5167 KiB

Open AccessArticle

Transcriptome-Wide Evaluation Characterization of microRNAs and Assessment of Their Functional Roles as Regulators of Diapause in Ostrinia furnacalis Larvae (Lepidoptera: Crambidae)

by Hongyue Ma, Ye Liu, Xun Tian, Yujie Chen and Shujing Gao

Insects 2024, 15(9), 702; https://doi.org/10.3390/insects15090702 - 14 Sep 2024

Abstract

microRNAs (miRNAs) function as vital regulators of diapause in insects through their ability to post-transcriptionally suppress target gene expression. In this study, the miRNA of Ostrinia furnacalis, an economically important global crop pest species, was characterized. For the included analyses, 9 small RNA [...] Read more.

microRNAs (miRNAs) function as vital regulators of diapause in insects through their ability to post-transcriptionally suppress target gene expression. In this study, the miRNA of Ostrinia furnacalis, an economically important global crop pest species, was characterized. For the included analyses, 9 small RNA libraries were constructed using O. furnacalis larvae in different diapause states (non-diapause, ND; diapause, D; diapause-termination, DT). The results identified 583 total miRNAs, of which 256 had previously been identified, whereas 327 were novel. Furthermore, comparison analysis revealed that 119 and 27 miRNAs were differentially expressed in the D vs. ND and DT vs. D, respectively. Moreover, the expression patterns of their miRNAs were also analyzed. GO and KEGG analysis of the target genes of differentially expressed miRNAs highlighted the importance of these miRNAs as diapause regulators in O. furnacalis, especially through metabolic processes, endocrine processes, 20-hydroxyecdysone, and circadian clock signaling pathways. In summary, this study highlighted the involvement of specific miRNAs in the control of diapause in O. furnacalis. To the best of our knowledge, this is the first study to identify miRNA expression patterns in O. furnacalis, thereby providing reference and novel evidence enhancing our current understanding of how small RNAs influence insect diapause. Full article

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

► Show Figures

Graphical abstract

13 pages, 1663 KiB

Open AccessArticle

Seasonal Abundance and Diversity of Culicoides Biting Midges in Livestock Sheds in Kanchanaburi Province, Thailand

by Arunrat Thepparat, Naoto Kamata, Padet Siriyasatien, Waranya Prempree, Kannika Dasuntad, Boonruam Chittsamart and Sunisa Sanguansub

Insects 2024, 15(9), 701; https://doi.org/10.3390/insects15090701 - 14 Sep 2024

Abstract

Culicoides biting midges were collected using UV light traps from nine livestock farms in Kanchanaburi Province, Thailand. Collections were made one night per month from June 2020 to May 2021 to determine the seasonal changes and spatial distribution of the Culicoides assemblage. The [...] Read more.

Culicoides biting midges were collected using UV light traps from nine livestock farms in Kanchanaburi Province, Thailand. Collections were made one night per month from June 2020 to May 2021 to determine the seasonal changes and spatial distribution of the Culicoides assemblage. The influence of four environmental factors (temperature, rainfall, humidity, and wind speed), types of animals in each shed (cattle, pigs, and avians), and neighboring animals (those in the other sheds and their proximity) were assessed. A subsample of 130,670 out of a total of 224,153 specimens collected was identified and counted. The collections were predominantly female (76.9%), though males were also commonly collected (23.1%). The dominant species included C. peregrinus (97,098 individuals; 43.0%), C. oxystoma (55,579; 24.6%), C. arakawae (45,996; 20.4%), and C. imicola (15,703; 7.0%), while other species accounted for the remaining 9777 individuals (4.4%). Trap captures were strongly influenced by seasons and animal sheds. Cattle exhibited the greatest effect on the community, likely due to their large biomass. Humidity and temperature had a positive effect on trap captures, whereas wind speed exhibited a negative effect. Cattle positively influenced all major species, except for C. arakawae, which showed a positive association with avians. A “neighboring effect” was also observed. Additionally, the lowest dispersal ability of C. arakawae was suggested. Full article

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

► Show Figures

Figure 1

16 pages, 2121 KiB

Open AccessArticle

Full-Length Transcriptome Profiling of the Complete Mitochondrial Genome of Sericothrips houjii (Thysanoptera: Thripidae: Sericothripinae) Featuring Extensive Gene Rearrangement and Duplicated Control Regions

by Qiaoqiao Liu, Shiwen Xu, Jia He, Wanzhi Cai, Xingmin Wang and Fan Song

Insects 2024, 15(9), 700; https://doi.org/10.3390/insects15090700 - 14 Sep 2024

Abstract

The mitochondrial genome (mitogenome) of Thysanoptera has extensive gene rearrangement, and some species have repeatable control regions. To investigate the characteristics of the gene expression, transcription and post-transcriptional processes in such extensively gene-rearranged mitogenomes, we sequenced the mitogenome and mitochondrial transcriptome of Sericothrips [...] Read more.

The mitochondrial genome (mitogenome) of Thysanoptera has extensive gene rearrangement, and some species have repeatable control regions. To investigate the characteristics of the gene expression, transcription and post-transcriptional processes in such extensively gene-rearranged mitogenomes, we sequenced the mitogenome and mitochondrial transcriptome of Sericothrips houjii to analyze. The mitogenome was 14,965 bp in length and included two CRs contains 140 bp repeats between COIII-trnN (CR1) and trnT-trnP (CR2). Unlike the putative ancestral arrangement of insects, S. houjii exhibited only six conserved gene blocks encompassing 14 genes (trnL2-COII, trnD-trnK, ND2-trnW, ATP8-ATP6, ND5-trnH-ND4-ND4L and trnV-lrRNA). A quantitative transcription map showed the gene with the highest relative expression in the mitogenome was ND4-ND4L. Based on analyses of polycistronic transcripts, non-coding RNAs (ncRNAs) and antisense transcripts, we proposed a transcriptional model of this mitogenome. Both CRs contained the transcription initiation sites (TISs) and transcription termination sites (TTSs) of both strands, and an additional TIS for the majority strand (J-strand) was found within antisense lrRNA. The post-transcriptional cleavage processes followed the “tRNA punctuation” model. After the cleavage of transfer RNAs (tRNAs), COI and ND3 matured as bicistronic mRNA COI/ND3 due to the translocation of intervening tRNAs, and the 3′ untranslated region (UTR) remained in the mRNAs for COII, COIII, CYTB and ND5. Additionally, isoform RNAs of ND2, srRNA and lrRNA were identified. In summary, the relative mitochondrial gene expression levels, transcriptional model and post-transcriptional cleavage process of S. houjii are notably different from those insects with typical mitochondrial gene arrangements. In addition, the phylogenetic tree of Thripidae including S. houjii was reconstructed. Our study provides insights into the phylogenetic status of Sericothripinae and the transcriptional and post-transcriptional regulation processes of extensively gene-rearranged insect mitogenomes. Full article

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

► Show Figures

Figure 1

14 pages, 299 KiB

Open AccessArticle

Thrips (Thysanoptera: Terebrantia) in Nectarine Orchards in North-East Spain: Species Diversity and Fruit Damage

by Albert Gallardo-Ferrand, Lucía Adriana Escudero-Colomar, Jesús Avilla and Dolors Bosch-Serra

Insects 2024, 15(9), 699; https://doi.org/10.3390/insects15090699 - 14 Sep 2024

Abstract

Thrips constitute one of the main nectarine pests, with damage either in flowering or before harvesting (silvering). Several species are associated with damage to flowers, but Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) is the main species associated with summer damage in Europe. Tree canopies [...] Read more.

Thrips constitute one of the main nectarine pests, with damage either in flowering or before harvesting (silvering). Several species are associated with damage to flowers, but Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) is the main species associated with summer damage in Europe. Tree canopies of nectarine orchards under organic and integrated management were sampled in Lleida and Girona at four key moments of the season (bud burst, full flowering, fruit setting stage, and colorization of the fruit) during 2021 and 2022 to determine the species composition in the area and the damage caused during fruit maturation. Adult individuals in flowers, leaves, and fruit surfaces were collected and identified, and silvering damage to the fruit surface was assessed in the Lleida area. Fifteen species in Lleida and 10 species in Girona were collected from the tree canopy. Organic orchards in Lleida showed lower populations and silvering damage levels when compared with integrated orchards. Thrips fuscipennis Haliday (Thysanoptera: Thripidae) 1836 was the main species in Lleida during harvest, and Frankliniella occidentalis (Pergande) 1895 was the main species in Girona. Due to their predominance, both species were associated with silvering damage during fruit maturation. Full article

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

Journal Description

Insects

Latest Articles

Journal Menu

Journal Browser

Highly Accessed Articles

Latest Books

E-Mail Alert

News

Topics

Conferences

Special Issues

Topical Collections

Further Information

Guidelines

MDPI Initiatives

Follow MDPI