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Insects
Volume 13
Issue 9
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Insects, Volume 13, Issue 9 (September 2022) – 99 articles

Cover Story (view full-size image): While consumption by predators directly reduces prey populations, some studies have shown that even the mere threat of predation can negatively impact the health and fitness of prey. This is referred to as the enemy-risk effect. The larvae of the diamondback moth (Plutella xylostella) show a characteristic enemy-escape behavior where they violently wriggle backwards and drop from their host plants, usually suspending themselves with a silk thread. We found that there was a developmental cost associated with this enemy avoidance. Larvae threatened by parasitoid wasps developed slower and became smaller adult moths. These physiological changes coincided with a change in caterpillar behavior to feed on older foliage, and the host plant species appeared to influence the severity of the enemy-risk effects. View this paper
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13 pages, 2081 KiB  
Communication
Optimized In Vitro CRISPR/Cas9 Gene Editing Tool in the West Nile Virus Mosquito Vector, Culex quinquefasciatus
by Tran Zen B. Torres, Brian C. Prince, Alexis Robison and Claudia Rückert
Insects 2022, 13(9), 856; https://doi.org/10.3390/insects13090856 - 19 Sep 2022
Cited by 2 | Viewed by 3228
Abstract
Culex quinquefasciatus mosquitoes are a globally widespread vector of multiple human and animal pathogens, including West Nile virus, Saint Louis encephalitis virus, and lymphatic filariasis. Since the introduction of West Nile virus to the United States in 1999, a cumulative 52,532 cases have [...] Read more.
Culex quinquefasciatus mosquitoes are a globally widespread vector of multiple human and animal pathogens, including West Nile virus, Saint Louis encephalitis virus, and lymphatic filariasis. Since the introduction of West Nile virus to the United States in 1999, a cumulative 52,532 cases have been reported to the CDC, including 25,849 (49.2%) neuroinvasive cases and 2456 (5%) deaths. Viral infections elicit immune responses in their mosquito vectors, including the RNA interference (RNAi) pathway considered to be the cornerstone antiviral response in insects. To investigate mosquito host genes involved in pathogen interactions, CRISPR/Cas9-mediated gene-editing can be used for functional studies of mosquito-derived cell lines. Yet, the tools available for the study of Cx. quinquefasciatus-derived (Hsu) cell lines remain largely underdeveloped compared to other mosquito species. In this study, we constructed and characterized a Culex-optimized CRISPR/Cas9 plasmid for use in Hsu cell cultures. By comparing it to the original Drosophila melanogaster CRISPR/Cas9 plasmid, we showed that the Culex-optimized plasmid demonstrated highly efficient editing of the genomic loci of the RNAi proteins Dicer-2 and PIWI4 in Hsu cells. These new tools support our ability to investigate gene targets involved in mosquito antiviral response, and thus the future development of gene-based vector control strategies. Full article
(This article belongs to the Section Insect Molecular Biology and Genomics)
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20 pages, 3688 KiB  
Article
Identification and Spread of the Ghost Silverfish (Ctenolepisma calvum) among Museums and Homes in Europe
by Pascal Querner, Nikolaus Szucsich, Bill Landsberger, Sven Erlacher, Lukasz Trebicki, Michał Grabowski and Peter Brimblecombe
Insects 2022, 13(9), 855; https://doi.org/10.3390/insects13090855 - 19 Sep 2022
Cited by 14 | Viewed by 8269
Abstract
Ctenolepisma calvum was first described in Sri Lanka (Ceylon) in 1910, and this island is probably the origin of this species. Later, it was also found in the Caribbean (Cuba and Trinidad and Tobago). Up until the present, it has only been identified [...] Read more.
Ctenolepisma calvum was first described in Sri Lanka (Ceylon) in 1910, and this island is probably the origin of this species. Later, it was also found in the Caribbean (Cuba and Trinidad and Tobago). Up until the present, it has only been identified within buildings (a synanthropic species), and its natural habitat is unknown. In 2007, it was discovered in Germany and was considered a neobiotic species of Lepismatidae in Europe. It has rapidly spread throughout Europe and beyond in recent years. This led us to analyze the available data of the first occurrences in Germany, Austria, and other European countries. Furthermore, we compared the spread inside of museums in Vienna (Austria) and Berlin (Germany). These museums have been monitored for a long period with sticky traps, representing the best source of information on the dispersion dynamics of Ctenolepisma calvum. We found a scattered occurrence of this species in 18 countries in Europe (including Russia and Ukraine). The first record for Poland has not previously been published; however, this species has been present there since 2014. Surprisingly, it was found in Hungary in 2003, but a record was only published online in 2021. Additionally, in Germany and Austria, where most data are available, the spread of the species does not follow any clear pattern. In museums in Berlin, the species has only been found in one location. In contrast, the species rapidly spread in museums in Vienna between 2014 and 2021, from four to 30 locations, and it is now a well-established species with occasional high abundance. We examined the spread of the species at three spatial scales: (i) Europe, (ii) national, and (iii) regional. Our observations indicate that it is possibly distributed with materials (packaging material, hygiene articles, paper, cardboard, and collection items). Little is yet known about the biology of this introduced pest. We describe its preferred habitat within buildings, its climate requirements, and its potential to act as a new museum pest in Central Europe. This species seems to thrive at room temperature in buildings. Further impact on the species due to climate change in the future is also discussed. We offer a simple morphological key and a detailed identification table to help correct species identification. Full article
(This article belongs to the Special Issue Advances in Urban Pest Management in Europe)
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35 pages, 2144 KiB  
Review
Lymantria dispar (L.) (Lepidoptera: Erebidae): Current Status of Biology, Ecology, and Management in Europe with Notes from North America
by Maria C. Boukouvala, Nickolas G. Kavallieratos, Anna Skourti, Xavier Pons, Carmen López Alonso, Matilde Eizaguirre, Enrique Benavent Fernandez, Elena Domínguez Solera, Sergio Fita, Tanja Bohinc, Stanislav Trdan, Paraskevi Agrafioti and Christos G. Athanassiou
Insects 2022, 13(9), 854; https://doi.org/10.3390/insects13090854 - 19 Sep 2022
Cited by 32 | Viewed by 6976
Abstract
The European Spongy moth, Lymantria dispar (L.) (Lepidoptera: Erebidae), is an abundant species found in oak woods in Central and Southern Europe, the Near East, and North Africa and is an important economic pest. It is a voracious eater and can completely defoliate [...] Read more.
The European Spongy moth, Lymantria dispar (L.) (Lepidoptera: Erebidae), is an abundant species found in oak woods in Central and Southern Europe, the Near East, and North Africa and is an important economic pest. It is a voracious eater and can completely defoliate entire trees; repeated severe defoliation can add to other stresses, such as weather extremes or human activities. Lymantria dispar is most destructive in its larval stage (caterpillars), stripping away foliage from a broad variety of trees (>500 species). Caterpillar infestation is an underestimated problem; medical literature reports that established populations of caterpillars may cause health problems to people and animals. Inflammatory reactions may occur in most individuals after exposure to setae, independent of previous exposure. Currently, chemical and mechanical methods, natural predators, and silvicultural practices are included for the control of this species. Various insecticides have been used for its control, often through aerial sprayings, which negatively affect biodiversity, frequently fail, and are inappropriate for urban/recreational areas. However, bioinsecticides based on various microorganisms (e.g., entomopathogenic viruses, bacteria, and fungi) as well as technologies such as mating disruption using sex pheromone traps have replaced insecticides for the management of L. dispar. Full article
(This article belongs to the Special Issue Integrated Pest Management in Agricultural Crops and Forest Ecosystems)
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11 pages, 1450 KiB  
Article
Energy Consumption and Cold Hardiness of Diapausing Fall Webworm Pupae
by Lvquan Zhao, Xinmei Wang, Zheng Liu and Alex S. Torson
Insects 2022, 13(9), 853; https://doi.org/10.3390/insects13090853 - 19 Sep 2022
Cited by 8 | Viewed by 2091
Abstract
Diapause and cold hardiness are essential components of winter survival for most insects in temperate zones. The fall webworm, Hyphantria cunea, overwinters in a pupal diapause. In this study, we investigated the energy consumption and cold hardiness of diapausing pupae. We found [...] Read more.
Diapause and cold hardiness are essential components of winter survival for most insects in temperate zones. The fall webworm, Hyphantria cunea, overwinters in a pupal diapause. In this study, we investigated the energy consumption and cold hardiness of diapausing pupae. We found that lipid content decreased from October to November and stabilized from November to March. Glycogen content decreased by 61.3% and 52.2% for females and males, respectively, from October to November, and decreased slowly from November to March. We also observed a significant increase in trehalose concentrations as ambient temperatures decreased from October to November and a decrease in trehalose as temperatures increased again in March. We did not observe substantial changes in pupal supercooling points among the dates sampled. In addition, prolonged pupal development time reduced their survival rate and had no significant effect on post-diapause adult body mass and fecundity but reduced egg diameter in females. These results suggest that the energy consumption of H. cunea pupae during early diapause depends on lipid and glycogen, while it shifts to depend on glycogen or other energy stores in the mid- and late diapause stages. Our results also suggest that the prolonged development time of diapausing pupae had a negative effect on post-diapause fitness. Full article
(This article belongs to the Section Insect Physiology, Reproduction and Development)
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16 pages, 2191 KiB  
Article
Transcriptome and Metabolome Analysis Reveals the Importance of Amino-Acid Metabolism in Spodoptera Frugiperda Exposed to Spinetoram
by Zupeng Gao, Raufa Batool, Weifeng Xie, Xiaodan Huang and Zhenying Wang
Insects 2022, 13(9), 852; https://doi.org/10.3390/insects13090852 - 19 Sep 2022
Cited by 5 | Viewed by 2671
Abstract
Pests are inevitably exposed to sublethal and lethal doses in the agroecosystem following the application of pesticides indispensable to protect food sources. The effect of spinetoram on amino-acid metabolism of fall armyworm, Spodoptera frugiperda (J.E. Smith), was investigated, at the dose of LC [...] Read more.
Pests are inevitably exposed to sublethal and lethal doses in the agroecosystem following the application of pesticides indispensable to protect food sources. The effect of spinetoram on amino-acid metabolism of fall armyworm, Spodoptera frugiperda (J.E. Smith), was investigated, at the dose of LC10 and LC90, by transcriptome and LC-MS/MS analysis. Using statistics-based analysis of both POS and NEG mode, a total of 715,501 metabolites in S. frugiperda were significantly changed after spinetoram treatment. The enhancement of glucose metabolism provides energy support for detoxification in larvae. The decrease in valine and isoleucine is associated with an increase in leucine, without maintaining the conservation of citric acid in the larvae. The down-regulation of phenylalanine may retard the tricarboxylic acid cycle to produce GTP. The abundance of lysine was decreased in response to spinetoram exposure, which damages the nervous system of the larvae. The abundance of arginine increases and causes non-functional contraction of the insect’s muscles, causing the larva to expend excess energy. Tryptophan provides an important substrate for eliminating ROS. The changes in glutamic acid, aspartic acid, and lysine cause damage to the nerve centers of the larvae. The results of transcriptome and LC-MS/MS analysis revealed the effects of pesticide exposure on amino-acid metabolism of S. frugiperda successfully and provide a new overview of the response of insect physio-biochemistry against pesticides. Full article
(This article belongs to the Section Insect Molecular Biology and Genomics)
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12 pages, 6058 KiB  
Article
Photosensitivity of Dispersing Cryptic Date Stone Beetles Coccotrypes dactyliperda (Coleoptera, Curculionidae, Scolytinae)—A Pilot Study
by Dirk H. R. Spennemann
Insects 2022, 13(9), 851; https://doi.org/10.3390/insects13090851 - 19 Sep 2022
Cited by 1 | Viewed by 1719
Abstract
The date stone beetle, Coccotrypes dactyliperda, is a cryptic spermatophagus species that spends almost its entire life cycle inside the seeds of palms, esp. Phoenix sp. Only during dispersal, when the host seed has been largely eaten out, do females emerge for [...] Read more.
The date stone beetle, Coccotrypes dactyliperda, is a cryptic spermatophagus species that spends almost its entire life cycle inside the seeds of palms, esp. Phoenix sp. Only during dispersal, when the host seed has been largely eaten out, do females emerge for a short period of time in search of a fresh seed in which to establish new brood galleries. Previous work indicated that C. dactyliperda might be photophobic, preferring to emerge from seeds during night hours, whereas anecdotal evidence suggested that the beetles might be photophilic in terms of their movements post emergence. This paper examines the photosensitivity of the species under controlled laboratory conditions. The results show that C. dactyliperda, once removed from the brood chamber, is attracted by and moves faster to a light source, but that the color of the lit surface (red, blue, green, black) has no influence on either direction or crawl speed. Full article
(This article belongs to the Special Issue Analysis of Small-Scale Insect Movement)
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18 pages, 26867 KiB  
Article
De Novo Transcription Responses Describe Host-Related Differentiation of Paracoccus marginatus (Hemiptera: Pseudococcidae)
by Lizhen Zheng, Jianyu Li, Mengzhu Shi, Yanting Chen, Xiaoyun He and Jianwei Fu
Insects 2022, 13(9), 850; https://doi.org/10.3390/insects13090850 - 19 Sep 2022
Cited by 2 | Viewed by 2248
Abstract
Paracoccus marginatus (Hemiptera: Pseudococcidae) is an invasive pest with a diverse host range, strong diffusion, and high fecundity. It has been observed that P. marginatus feeding on Carica papaya have a higher survival rate, fecundity, and longer lifespan than P. marginatus feeding on [...] Read more.
Paracoccus marginatus (Hemiptera: Pseudococcidae) is an invasive pest with a diverse host range, strong diffusion, and high fecundity. It has been observed that P. marginatus feeding on Carica papaya have a higher survival rate, fecundity, and longer lifespan than P. marginatus feeding on Solanum tuberosum, indicating their successful adaptation to C. papaya; however, the mechanisms underlying host plant adaptation remain unclear. Therefore, RNA-seq was performed to study the transcriptional responses of P. marginatus feeding on C. papaya and S. tuberosum plants. A total of 408 genes with significant differential expression were defined; most of them were downregulated in S. tuberosum, including those of digestive enzymes, detoxifying enzymes, ribosomes, and reproductive-related genes, which may result from the adaptation of the host to nutritional needs and changes in toxic chemical levels. Enrichment analysis of the Kyoto Encyclopedia of Genes and Genomes showed that lysosome and longevity regulating pathways related to digestion, detoxification, and longevity were enriched. We suggest that C. papaya is a more suitable host than S. tuberosum, and downregulated target genes may have important effects on the adaptation of P. marginatus to host transfer. Full article
(This article belongs to the Special Issue Adaption of Herbivorous Insects to Plant Chemical Defense)
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12 pages, 3665 KiB  
Article
Diversity and Distribution of Whiteflies Colonizing Cassava in Eastern Democratic Republic of Congo
by Clérisse M. Casinga, Everlyne N. Wosula, Mouritala Sikirou, Rudolph R. Shirima, Carine M. Munyerenkana, Leon N. Nabahungu, Benoit K. Bashizi, Henry Ugentho, Godefroid Monde and James P. Legg
Insects 2022, 13(9), 849; https://doi.org/10.3390/insects13090849 - 19 Sep 2022
Cited by 4 | Viewed by 1835
Abstract
The present study characterizes Bemisia tabaci and Bemisia afer from cassava in eastern Democratic Republic of Congo (DRC). The Mitochondrial COI sequencing revealed the occurrence of six cassava B. tabaci mitotypes, which were designated into four haplogroups (SSA-ECA, SSA-CA, SSA2, and SSA-ESA) using [...] Read more.
The present study characterizes Bemisia tabaci and Bemisia afer from cassava in eastern Democratic Republic of Congo (DRC). The Mitochondrial COI sequencing revealed the occurrence of six cassava B. tabaci mitotypes, which were designated into four haplogroups (SSA-ECA, SSA-CA, SSA2, and SSA-ESA) using KASP SNP genotyping. SSA-ECA (72%) was the most prevalent and occurred in the northern part of the surveyed area, in the Ituri and Nord/Sud-Kivu provinces, whilst SSA-CA (21%) was present in the south, primarily in Haut-Katanga. SSA-ECA was predominant in the areas of north-eastern DRC most severely affected by cassava brown streak disease and was also reported in the new outbreak area in Pweto territory, Haut-Katanga, in the south. Bemisia afer comprised two major clusters with 85.5% of samples in cluster one, while the rest were in cluster two, which has no reference sequence in GenBank. This study provides important information on the genetic diversity of B. tabaci and B. afer in eastern DRC. This knowledge will be used as a basis for further studies to understand and to identify the role of whitefly haplogroups, their population densities and consequences for virus epidemics and spread as well as leading to improved vector and virus management strategies. Full article
(This article belongs to the Section Insect Molecular Biology and Genomics)
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14 pages, 690 KiB  
Article
Host and Seasonal Effects on the Abundance of Bean Leaf Beetles (Ootheca spp.) (Coleoptera: Chrysomelidae) in Northern Uganda
by Moses Lutaakome, Samuel Kyamanywa, Pamela Paparu, Samuel Olaboro, Charles Halerimana, Stanley Tamusange Nkalubo and Michael Hilary Otim
Insects 2022, 13(9), 848; https://doi.org/10.3390/insects13090848 - 18 Sep 2022
Cited by 1 | Viewed by 2535
Abstract
Bean leaf beetles (BLBs) (Ootheca spp.) are serious legume pests in Uganda and sub-Saharan Africa, but their ecology is not well understood. We planted host plants, viz., common bean, cowpea, and soybean, in an experiment in the hotspot areas of Arua and [...] Read more.
Bean leaf beetles (BLBs) (Ootheca spp.) are serious legume pests in Uganda and sub-Saharan Africa, but their ecology is not well understood. We planted host plants, viz., common bean, cowpea, and soybean, in an experiment in the hotspot areas of Arua and Lira districts in Northern Uganda in order to assess their influence on the density of adults and immature stages of BLBs in different seasons. Overall, the number of adults, larvae, and pupae were higher in cowpea than common bean and soybean plots. The number of adults were highest in cowpea (29.5 adults/15 plants) in Arua during the long rainy season (2018A). The number of adults did not differ significantly during short rains (season B) in 2017 and 2018. Similarly, in Lira district, the highest number of adult BLBs was in cowpea (4.6 beetles) compared to the common bean (2.7 beetles) and soybean plots, with a peak at four weeks after planting (WAP). During 2018A, larvae of BLBs first appeared at five WAP and seven WAP and peaked at 13 WAP and 11 WAP in Arua and Lira, respectively. The pupae were present in the soil after the harvesting of crops during 2018A, but peaked at seven WAP and eight WAP in 2018B season in Arua and Lira, respectively. The occurrence of below-ground adults in 2018B followed the peak abundance of pupae, although this was delayed until six WAP in Arua compared to Lira. We conclude that cowpea is the most preferred by adults and larvae compared to common bean and soybean. Similarly, the first rain season (2018A) attracted higher abundance and damage than the second rain season. Management of the BLBs should thus take into consideration avoidance of host crop rotation and dealing with the below-ground stages. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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13 pages, 940 KiB  
Article
Assessment of Compaction, Temperature, and Duration Factors for Packaging and Transporting of Sterile Male Aedes aegypti (Diptera: Culicidae) under Laboratory Conditions
by Beni Ernawan, Tjandra Anggraeni, Sri Yusmalinar, Hadian Iman Sasmita, Nur Fitrianto and Intan Ahmad
Insects 2022, 13(9), 847; https://doi.org/10.3390/insects13090847 - 17 Sep 2022
Cited by 7 | Viewed by 2179
Abstract
Optimized conditions for the packaging and transportation of sterile males are crucial factors in successful SIT programs against mosquito vector-borne diseases. The factors influencing the quality of sterile males in packages during transportation need to be assessed to develop standard protocols. This study [...] Read more.
Optimized conditions for the packaging and transportation of sterile males are crucial factors in successful SIT programs against mosquito vector-borne diseases. The factors influencing the quality of sterile males in packages during transportation need to be assessed to develop standard protocols. This study was aimed to investigate the impact of compaction, temperature, and duration factors during packaging and transportation on the quality of gamma-sterilized male Ae. aegypti. Aedes aegypti males were sterilized at a dose of 70 Gy, compacted into Falcon tubes with densities of 40, 80, and 120 males/2 mL; and then exposed to temperatures of 7, 14, 21, and 28 °C. Each temperature setup was held for a duration of 3, 6, 12, 24, and 48 h at a 60 rpm constant vibration to simulate transportation. The parameters of mortality, flight ability, induced sterility, and longevity were investigated. Results showed that increases in density, temperature, and duration significantly increased mortality and reduced flight ability and longevity, but none of the factors significantly affected induced sterility. With a mortality rate of less than 20%, an escaping rate of more than 70%, considerable longevity, and the most negligible effect on induced sterility (approximately 98%), a temperature of 7 °C and a compaction density of 80 males/2 mL were shown to be optimized conditions for short-term transportation (no more than 24 h) with the minimum adverse effects compared with other condition setups. Full article
(This article belongs to the Special Issue Mosquito Handling, Transport, Release and Male Trapping Methods)
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16 pages, 760 KiB  
Review
Insights into the Use of Eco-Friendly Synergists in Resistance Management of Leptinotarsa decemlineata (Coleoptera: Chrysomelidae)
by Rana Muhammad Kaleem Ullah, Ayhan Gökçe, Allah Bakhsh, Muhammad Salim, Hai Yan Wu and Muhammad Nadir Naqqash
Insects 2022, 13(9), 846; https://doi.org/10.3390/insects13090846 - 16 Sep 2022
Cited by 5 | Viewed by 2918
Abstract
The Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), is the most notorious insect pest of potato globally. Injudicious use of insecticides for management of this pest has resulted in resistance to all major groups of insecticides along with many human, animal health, and [...] Read more.
The Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), is the most notorious insect pest of potato globally. Injudicious use of insecticides for management of this pest has resulted in resistance to all major groups of insecticides along with many human, animal health, and environmental concerns. Additionally, the input cost of insecticide development/discovery is markedly increasing because each year thousands of chemicals are produced and tested for their insecticidal properties, requiring billions of dollars. For the management of resistance in insect pests, synergists can play a pivotal role by reducing the application dose of most insecticides. These eco-friendly synergists can be classified into two types: plant-based synergists and RNAi-based synergists. The use of plant-based and RNAi-based synergists in resistance management of insect pests can give promising results with lesser environmental side effects. This review summarizes the resistance status of CPB and discusses the potential advantage of plant-based and RNAi-based synergists for CPB resistance management. It will motivate researchers to further investigate the techniques of using plant- and RNAi-based synergists in combination with insecticides. Full article
(This article belongs to the Special Issue The Evolution of Pesticide Resistance)
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11 pages, 825 KiB  
Article
Field and Cage Studies Show No Effects of Exposure to Flonicamid on Honey Bees at Field-Relevant Concentrations
by William G. Meikle and Milagra Weiss
Insects 2022, 13(9), 845; https://doi.org/10.3390/insects13090845 - 16 Sep 2022
Cited by 4 | Viewed by 2184
Abstract
The extent to which insecticides harm non-target beneficial insects is controversial. The effects of long-term exposure on honey bees to sublethal concentrations of flonicamid, a pyridinecarboxamide compound used as a systemic insecticide against sucking insects, were examined in a field study and two [...] Read more.
The extent to which insecticides harm non-target beneficial insects is controversial. The effects of long-term exposure on honey bees to sublethal concentrations of flonicamid, a pyridinecarboxamide compound used as a systemic insecticide against sucking insects, were examined in a field study and two cage studies. The field study involved the continuous weight, temperature, and CO2 monitoring of 18 honey bee colonies, 6 of which were exposed over six weeks to 50 ppb flonicamid in sugar syrup, 6 exposed to 250 ppb flonicamid in syrup, and 6 exposed to unadulterated syrup (control). Treatments were derived from concentrations observed in honey samples in a published study. No effects were observed on foraging activity, hive weight gain, thermoregulation, or average CO2 concentrations. However, Varroa mite infestations may have also contributed to experimental variability. The two cage studies, in which cages (200 newly-emerged bees in each) were exposed to the same flonicamid concentrations as the field study and kept in a variable-temperature incubator, likewise did not show any experiment-wide effects on survivorship, thermoregulation, or syrup consumption. These results suggest that field applications of flonicamid that result in concentrations as high as 250 ppb in honey may be largely safe for honey bees. Full article
(This article belongs to the Section Insect Societies and Sociality)
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18 pages, 2349 KiB  
Article
Epidemiology of the Microsporidium Nosema ceranae in Four Mediterranean Countries
by Clara Jabal-Uriel, Laura Barrios, Anne Bonjour-Dalmon, Shiran Caspi-Yona, Nor Chejanovsly, Tal Erez, Dora Henriques, Mariano Higes, Yves Le Conte, Ana R. Lopes, Aránzazu Meana, Maria Alice Pinto, Maritza Reyes-Carreño, Victoria Soroker and Raquel Martín-Hernández
Insects 2022, 13(9), 844; https://doi.org/10.3390/insects13090844 - 16 Sep 2022
Cited by 9 | Viewed by 2611
Abstract
Nosema ceranae is a highly prevalent intracellular parasite of honey bees’ midgut worldwide. This Microsporidium was monitored during a long-term study to evaluate the infection at apiary and intra-colony levels in six apiaries in four Mediterranean countries (France, Israel, Portugal, and Spain). Parameters [...] Read more.
Nosema ceranae is a highly prevalent intracellular parasite of honey bees’ midgut worldwide. This Microsporidium was monitored during a long-term study to evaluate the infection at apiary and intra-colony levels in six apiaries in four Mediterranean countries (France, Israel, Portugal, and Spain). Parameters on colony strength, honey production, beekeeping management, and climate were also recorded. Except for São Miguel (Azores, Portugal), all apiaries were positive for N. ceranae, with the lowest prevalence in mainland France and the highest intra-colony infection in Israel. A negative correlation between intra-colony infection and colony strength was observed in Spain and mainland Portugal. In these two apiaries, the queen replacement also influenced the infection levels. The highest colony losses occurred in mainland France and Spain, although they did not correlate with the Nosema infection levels, as parasitism was low in France and high in Spain. These results suggest that both the effects and the level of N. ceranae infection depends on location and beekeeping conditions. Further studies on host-parasite coevolution, and perhaps the interactions with other pathogens and the role of honey bee genetics, could assist in understanding the difference between nosemosis disease and infection, to develop appropriate strategies for its control. Full article
(This article belongs to the Section Insect Behavior and Pathology)
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22 pages, 6662 KiB  
Article
Fine-Structural Morphology of the Mouthparts of the Polyphagous Invasive Planthopper, Ricania speculum (Walker) (Hemiptera: Fulgoromorpha: Ricaniidae)
by Tiantian Gao, Jolanta Brożek and Wu Dai
Insects 2022, 13(9), 843; https://doi.org/10.3390/insects13090843 - 16 Sep 2022
Viewed by 2433
Abstract
Mouthparts are the crucial sensory and feeding organs associated with food detection and feeding in insects. The Asian ricaniid planthopper Ricania speculum (Walker), recently introduced into Europe, can cause severe economic damage by sucking the phloem sap of tea, camphor, citrus, black locust [...] Read more.
Mouthparts are the crucial sensory and feeding organs associated with food detection and feeding in insects. The Asian ricaniid planthopper Ricania speculum (Walker), recently introduced into Europe, can cause severe economic damage by sucking the phloem sap of tea, camphor, citrus, black locust and other plants using piercing-sucking mouthparts. To facilitate comprehensive understanding of feeding mechanisms in the Ricaniidae, the fine structure of the mouthparts of Ricania speculum was observed by scanning electron microscopy for the first time. The mouthparts are tubular, consist of a cone-shaped labrum, with a wrinkled epidermis and without sensilla; the tubular labium is divided into three segments: a slender stylet fascicle consisting of two mandibular stylets with four ridged processes and a row of longitudinal striations on the distal part of the outer surface; and two maxillary stylets with a smooth and sharp distal part, interlocked to form a larger food canal and a smaller salivary canal. On the labium, 15 kinds of sensilla of different functions were recognized. Two rows of short sensilla basiconica (SB I) are symmetrically distributed along the labial groove on the first segment. Two pairs of long sensilla basiconica (SB II) (proprioceptors) are on both sides of the labial groove at the junction of the second and third segments. A placoid, flattened sensillum (SPF) is symmetrically located laterally on the proximal end of the last segment and several flattened sensilla campaniformia (SFC) were visible on the ventral side on the second and third segments. The distribution of four types (I–IV) of sensilla cheatica of different lengths on the dorsal surface of the labium is significantly denser than on the lateral and ventral surfaces. The labial apex is divided into dorsal and ventral sensory fields, mainly including uniporous long peg sensilla (I), as well as smaller peg sensilla (II) and nonporous peg sensilla (PGSN) on each dorsal field. These nonporous sensilla basiconica (BSN I and III) occur on the ventral sensory fields and are constant in number and distribution. The nonporous sensilla basiconica (BSN II) are symmetrically arranged near the opening of the stylet fascicle similarly to two oval multiporous plate sensilla (OPSM). The sensilla arrangement is slightly different from that observed in previously studied Fulgoromorpha using scanning electron micrographs, which may reflect differences in feeding preference or behavior. Full article
(This article belongs to the Special Issue Feeding Organs in Hexapoda)
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11 pages, 979 KiB  
Article
Repellency and Reduction of Offspring Emergence Potential of Some Botanical Extracts against Sitophilus zeamais (Coleoptera: Curculionidae) in Stored Maize
by Diaine Cortese, Matheus Moreno Mareco Da Silva, Gisele Silva de Oliveira, Rosilda Mara Mussury and Marcos Gino Fernandes
Insects 2022, 13(9), 842; https://doi.org/10.3390/insects13090842 - 16 Sep 2022
Cited by 2 | Viewed by 2613
Abstract
Botanical repellents are, usually, considered safe to control Sitophilus zeamais, the main pest of stored maize, as they do not leave toxic residues in food, in addition to having lower costs than chemical insecticides. The aim of this study was to evaluate [...] Read more.
Botanical repellents are, usually, considered safe to control Sitophilus zeamais, the main pest of stored maize, as they do not leave toxic residues in food, in addition to having lower costs than chemical insecticides. The aim of this study was to evaluate the repellency potential and the reduction of emerged offspring of botanical extracts, of Schinus terebinthifolius, Ludwigia sericea, L. tomentosa, L. nervosa, L. longifolia, and use them as botanical insecticides for S. zeamais. For the repellency test, arenas were set up, containing 50 g of maize kernels exposed to aqueous extract, besides a control treatment. At the center of each arena, 100 insects were released. After 48 h, the proportion of insects in the treated grains was determined. To test the effects of the extracts on insect mating and egg-laying, free-choice and no-choice tests were performed. Insects in both tests remained for ten days for mating and egg-laying. After this period, insects were removed to evaluate the offspring emergence. Sixty days after grain infestation, the number of emerged insects was counted. All selected botanical extracts demonstrated repellent action against S. zeamais, even after 48 h of application. The L. nervosa aqueous extract significantly reduced the emergence of S. zeamais. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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14 pages, 7401 KiB  
Article
Record of New Termite (Blattodea, Termitidae) Species in Togo West Africa
by Toblie Quashie Effowe, Boris Dodji Kasseney, Abdoulaye Baïla Ndiaye and Adolé Isabelle Glitho
Insects 2022, 13(9), 841; https://doi.org/10.3390/insects13090841 - 15 Sep 2022
Cited by 1 | Viewed by 2159
Abstract
In Africa, despite their economic and ecological importance, termites are still relatively unknown. Their systematic remains uncertain, the approximate number of species for many biogeographic areas is underestimated, and there is still confusion in the identification of the species for many genera. This [...] Read more.
In Africa, despite their economic and ecological importance, termites are still relatively unknown. Their systematic remains uncertain, the approximate number of species for many biogeographic areas is underestimated, and there is still confusion in the identification of the species for many genera. This study combined morphological traits with morphometric measurements to determine several species collected in Togo and provided head illustrations of soldiers. Termites were sampled within the frame of transects laid in several landscapes inside three different parks including: Fosse aux Lions, Galangashie, and Fazao Malfakassa. Samples were grouped by morphospecies and measurements of part of the body (length and/or width of head, mandible, pronotum, gula, and hind tibia) were conducted. Twelve termite species including Foraminitermescorniferus, Lepidotermes sp., Noditermes cristifrons, Noditermes sp. 1 and Noditermes sp. 2, Promirotermes holmgren infera, Promirotermes sp., Unguitermes sp., Amitermes evuncifer, A. guineensis, A. truncatus, and A. spinifer were separated and pictured. Ten new species were added to the check list of the country, including five unidentified ones. Further studies such as biomolecular analysis should be carried out in order to clarify the status of these unknown species. Full article
(This article belongs to the Special Issue Selected Papers from the 1st International Electronic Conference on Entomology)
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11 pages, 8164 KiB  
Article
Comparative Analysis of Volatiles Emitted from Tomato and Pepper Plants in Response to Infection by Two Whitefly-Transmitted Persistent Viruses
by Saptarshi Ghosh, Shoshana Didi-Cohen, Alon Cna’ani, Svetlana Kontsedalov, Galina Lebedev, Vered Tzin and Murad Ghanim
Insects 2022, 13(9), 840; https://doi.org/10.3390/insects13090840 - 15 Sep 2022
Cited by 4 | Viewed by 3764
Abstract
The whitefly Bemisia tabaci is one of the most important agricultural pests due to its extreme invasiveness, insecticide resistance, and ability to transmit hundreds of plant viruses. Among these, Begomoviruses and recombinant whitefly-borne Poleroviruses are transmitted persistently. Several studies have shown that upon [...] Read more.
The whitefly Bemisia tabaci is one of the most important agricultural pests due to its extreme invasiveness, insecticide resistance, and ability to transmit hundreds of plant viruses. Among these, Begomoviruses and recombinant whitefly-borne Poleroviruses are transmitted persistently. Several studies have shown that upon infection, plant viruses manipulate plant-emitted volatile organic compounds (VOCs), which have important roles in communication with insects. In this study, we profiled and compared the VOCs emitted by tomato and pepper plant leaves after infection with the Tomato yellow leaf curl virus (TYLCV) (Bogomoviruses) and the newly discovered Pepper whitefly-borne vein yellows virus (PeWBVYV) (Poleroviruses), respectively. The results identified shared emitted VOCs but also uncovered unique VOC signatures for each virus and for whitefly infestation (i.e., without virus infection) independently. The results suggest that plants have general defense responses; however, they are also able to respond individually to infection with specific viruses or infestation with an insect pest. The results are important to enhance our understanding of virus- and insect vector-induced alteration in the emission of plant VOCs. These volatiles can eventually be used for the management of virus diseases/insect vectors by either monitoring or disrupting insect–plant interactions. Full article
(This article belongs to the Collection Plant Responses to Insect Herbivores)
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18 pages, 964 KiB  
Review
Mating and Sexual Selection in Empidine Dance Flies (Empididae)
by Rosalind L. Murray, Darryl T. Gwynne and Luc F. Bussière
Insects 2022, 13(9), 839; https://doi.org/10.3390/insects13090839 - 15 Sep 2022
Cited by 7 | Viewed by 3523
Abstract
Species whose behaviour or morphology diverges from typical patterns can provide unique insights on the evolutionary forces that promote diversity. Darwin recognised that while elaborate sexually selected traits mostly occurred among males, in a few species females possess such traits. Some species from [...] Read more.
Species whose behaviour or morphology diverges from typical patterns can provide unique insights on the evolutionary forces that promote diversity. Darwin recognised that while elaborate sexually selected traits mostly occurred among males, in a few species females possess such traits. Some species from the subfamily Empidinae (Diptera: Empididae) are among the animals that are often invoked to illustrate female ornaments. Empidines include taxa that exhibit varying levels of female ornament expression; some species possess multiple, elaborate female-specific ornaments while others have fewer and more modest adornments, and many species are altogether lacking discernible sexual ornamentation. This continuous variation in display traits in the Empidinae provides unique opportunities to explore the causes and consequences of sexually selected ornament expression. Here, we review the literature on sexual selection and mating systems in these flies and synthesise the evidence for various evolutionary forces that could conceivably create this impressive morphological and behavioural diversity, despite evolutionary constraints on female ornament exaggeration that help to explain its general rarity among animals. We also suggest some aspects of diversity that remain relatively unexplored or poorly understood, and close by offering suggestions for future research progress in the evolutionary ecology of mating behaviour among empidine flies. Full article
(This article belongs to the Special Issue Systematics, Evolution, and Diversity of Dance Flies (Diptera, Empidoidea))
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18 pages, 2500 KiB  
Article
Antibiotic Treatment Reduced the Gut Microbiota Diversity, Prolonged the Larval Development Period and Lessened Adult Fecundity of Grapholita molesta (Lepidoptera: Tortricidae)
by Xuan Zhang, Xing Wang, Zikun Guo, Xueying Liu, Ping Wang, Xiangqun Yuan and Yiping Li
Insects 2022, 13(9), 838; https://doi.org/10.3390/insects13090838 - 15 Sep 2022
Cited by 11 | Viewed by 3522
Abstract
Grapholita molesta, the oriental fruit moth, is a serious pest of fruit trees with host transfer characteristics worldwide. The gut microbiota, which plays a crucial part in insect physiology and ecology, can be influenced by many elements, such as antibiotics, temperature, diet, [...] Read more.
Grapholita molesta, the oriental fruit moth, is a serious pest of fruit trees with host transfer characteristics worldwide. The gut microbiota, which plays a crucial part in insect physiology and ecology, can be influenced by many elements, such as antibiotics, temperature, diet, and species. However, the effects of antibiotics on G. molesta gut microbiota are still unclear. In this study, we selected five common antibiotic agents to test the inhibition of G. molesta gut microbiota, and found ciprofloxacin shown the best antibacterial activity. After feeding 1 μg/mL of ciprofloxacin, the relative abundance of Actinobacteria and Cyanobacteria decreased significantly, while that of Firmicutes and Bacteroidetes increased. PICRUSt2 analysis indicated that most functional prediction categories were enriched in the G. molesta gut, including amino acid transport and metabolism, translation, ribosomal structure and biogenesis, carbohydrate transport and metabolism, transcription, cell wall/membrane/envelope biogenesis, and energy production and conversion. Finally, ciprofloxacin feeding significantly affected larval growth, development, and reproduction, resulting in prolonged larval development duration, shortened adult longevity, and significantly decreased single female oviposition and egg hatchability. In addition, we isolated and purified some culturable bacteria belonging to Proteobacteria, Firmicutes, Actinobacteria, and cellulase-producing bacteria from the G. molesta midgut. In brief, our results demonstrate that antibiotics can have an impact on G. molesta gut bacterial communities, which is beneficial for host growth and development, as well as helping female adults produce more fertile eggs. These results will thus provide a theoretical reference for developing new green control technology for G. molesta. Full article
(This article belongs to the Special Issue Arthropod Interactions and Pest Management in Fruit and Vegetable Crops)
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12 pages, 1421 KiB  
Article
Flight Performance, Fecundity, and Ovary Development of Grapholita molesta (Lepidoptera: Torticidae) at Different Ages
by Sha Su, Xiaohe Zhang, Jilong Zhang, Baojian Huang, Chengzhi Jian, Xiong Peng, Marc J. B. Vreysen and Maohua Chen
Insects 2022, 13(9), 837; https://doi.org/10.3390/insects13090837 - 14 Sep 2022
Cited by 5 | Viewed by 2334
Abstract
Grapholita molesta is one of the most serious pests in fruits orchards. Flight performance of male insects and fecundity of female insects are important quality control parameters when moths are mass-reared for use in environment-friendly control strategies such as the sterile insect technique [...] Read more.
Grapholita molesta is one of the most serious pests in fruits orchards. Flight performance of male insects and fecundity of female insects are important quality control parameters when moths are mass-reared for use in environment-friendly control strategies such as the sterile insect technique (SIT). However, information about flight performance, fecundity, and ovary development of G. molesta at different ages is scarce. In this study, we used a flight mill information system to measure the flight ability of female and male adults of G. molesta at different ages, and evaluated fecundity and ovarian development of female adults at different ages. The results demonstrated that the flight parameters (cumulative flight distance, cumulative flight time, maximum flight distance and maximum flight duration) of female and male G. molesta varied with age. Six-day-old female moths and three-day-old male moths were the strongest fliers, whereas the fecundity of one-day and two-day-old female moths was significantly lower than that of three to seven-day-old females. Five-day-old females had the highest fecundity. Their ovaries demonstrated mature eggs in the lateral and middle oviducts as of the third day post-emergence. It is suggested that the optimal age for moths to be released in SIT programs is three days, and moths older three days can be used for mass-rearing in a factory. Full article
(This article belongs to the Special Issue Improved Field Performance of Sterile Male Lepidoptera to Ensure Success in SIT Programmes)
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30 pages, 3474 KiB  
Article
The Effect of Feeding with Central European Local Mulberry Genotypes on the Development and Health Status of Silkworms and Quality Parameters of Raw Silk
by Andreja Urbanek Krajnc, Tamas Bakonyi, Istvan Ando, Eva Kurucz, Norbert Solymosi, Paula Pongrac and Rebeka Lucijana Berčič
Insects 2022, 13(9), 836; https://doi.org/10.3390/insects13090836 - 14 Sep 2022
Cited by 7 | Viewed by 2872
Abstract
Silkworm rearing activities ceased in the 1970′s in several European countries. Attempts on the re-establishment of ecological and sustainable sericulture in Slovenia and Hungary are ongoing. The aim of the study was to assess the usability of locally adapted mulberry genotypes for sericulture [...] Read more.
Silkworm rearing activities ceased in the 1970′s in several European countries. Attempts on the re-establishment of ecological and sustainable sericulture in Slovenia and Hungary are ongoing. The aim of the study was to assess the usability of locally adapted mulberry genotypes for sericulture and to estimate connections between leaf compound and silkworm performance parameters. A controlled feeding experiment of silkworms was performed to test the influence of leaves from selected trees on the growth of larvae, the health and microbiological status of larvae (e.g., gut bacterial microbiome, Bombyx mori nucleopolyhedrovirus infection), weight of cocoons and raw silk parameters. The Slovenian and Hungarian mulberry genotypes had significantly higher total protein contents, and lower total phenolic contents and differed significantly in some individual phenolics compared to the reference sericultural and fruit varieties. Significant differences were found in the contents of the macro- and microelements, namely S, Mn, Fe, and Sr. Based on correlative statistics and multivariate analysis, a combined positive influence of proteins, specific phenolics, and microelements on larval growth and silk thread parameters was predicted. The results of the study indicate that selected local Slovenian and Hungarian mulberry varieties are suitable for high-quality silk cocoon and raw silk production. Full article
(This article belongs to the Special Issue Silkworm and Silk: Traditional and Innovative Applications)
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17 pages, 3812 KiB  
Article
Transcriptome Analysis of Beet Webworm Shows That Histone Deacetylase May Affect Diapause by Regulating Juvenile Hormone
by Jin Cui, Kejian Lin, Linbo Xu, Fangzheng Yue, Liangbin Yu and Quanyi Zhang
Insects 2022, 13(9), 835; https://doi.org/10.3390/insects13090835 - 14 Sep 2022
Cited by 5 | Viewed by 2237
Abstract
The beet webworm (Loxostege sticticalis L.) is an important agricultural pest and can tolerate harsh environmental conditions by entering diapause. The diapause mechanism of beet webworm is unknown. Therefore, we conducted a transcriptomic study of the process from diapause induction to diapause [...] Read more.
The beet webworm (Loxostege sticticalis L.) is an important agricultural pest and can tolerate harsh environmental conditions by entering diapause. The diapause mechanism of beet webworm is unknown. Therefore, we conducted a transcriptomic study of the process from diapause induction to diapause release in beet webworms. The results revealed 393 gene modules closely related to the diapause of beet webworm. The hub gene of the red module was the HDACI gene, which acts through histone deacetylase (HDAC) enzymes. HDAC enzyme activity was regulated by the light duration and influenced the JH content under induced beet webworm diapause conditions (12 h light:12 h dark). In addition, transcriptomic data suggested that circadian genes may not be the key genes responsible for beet webworm diapause. However, we showed that the photoperiod affects HDAC enzyme activity, and HDAC can regulate the involvement of JH in beet webworm diapause. This study provided a new module for studying insect diapause and links histone acetylation and diapause at the transcriptome level. Full article
(This article belongs to the Section Insect Molecular Biology and Genomics)
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12 pages, 2333 KiB  
Article
Bta06987, Encoding a Peptide of the AKH/RPCH Family: A Role of Energy Mobilization in Bemisia tabaci
by Xiaofan Fan, Yong Liu, Zhuo Zhang, Zhanhong Zhang, Jing Peng, Yang Gao, Limin Zheng, Jianbin Chen, Jiao Du, Shuo Yan, Xuguo Zhou, Xiaobin Shi and Deyong Zhang
Insects 2022, 13(9), 834; https://doi.org/10.3390/insects13090834 - 13 Sep 2022
Cited by 2 | Viewed by 1908
Abstract
A neuropeptide precursor encoded by Bta06987 associates with AKH neuropeptide. In the AKH/RPCH family, these members have been demonstrated to participate in energy mobilization in many insects. In our research, the Bta06987 gene from Bemisia tabaci was cloned, and the amino acid sequence [...] Read more.
A neuropeptide precursor encoded by Bta06987 associates with AKH neuropeptide. In the AKH/RPCH family, these members have been demonstrated to participate in energy mobilization in many insects. In our research, the Bta06987 gene from Bemisia tabaci was cloned, and the amino acid sequence analysis was performed. During the starvation of B. tabaci, the mRNA level of Bta06987 showed a significant elevation. We investigated the functions of Bta06987 in B. tabaci using RNA interference (RNAi), and the adult females of B. tabaci after being fed with dsBta06987 showed a higher glycogen and triglyceride levels and lower trehalose content than the control. Furthermore, in the electrical penetration graph (EPG) experiment, B. tabaci showed changes in feeding behavior after feeding with dsBta06987, such as the reduction in parameters of E waveform percentage and total feeding time. Our findings might be helpful in developing strategies to control pest and plant virus transmission. Full article
(This article belongs to the Section Insect Molecular Biology and Genomics)
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14 pages, 4390 KiB  
Article
Parasitoid Wasps Can Manipulate Host Trehalase to the Benefit of Their Offspring
by Yan Song, Fengming Gu, Weihong Zhou, Ping Li, Fuan Wu and Sheng Sheng
Insects 2022, 13(9), 833; https://doi.org/10.3390/insects13090833 - 13 Sep 2022
Cited by 5 | Viewed by 2261
Abstract
Trehalase is an essential hydrolase of trehalose in insects. However, whether and how trehalase performs in the association of parasitoid wasps and their hosts still remains unknown. Here, the exact function of trehalase of the general cutworm Spodoptera litura after it was parasitized [...] Read more.
Trehalase is an essential hydrolase of trehalose in insects. However, whether and how trehalase performs in the association of parasitoid wasps and their hosts still remains unknown. Here, the exact function of trehalase of the general cutworm Spodoptera litura after it was parasitized by its predominant endoparasitoid Meterous pulchricornis was elucidated. Two trehalase genes (SlTre1, SlTre2) were identified, and they were highly expressed five days after parasitization by M. pulchricornis. Then, we successfully silenced SlTre1 and SlTre2 in parasitized third instar S. litura larvae. The content of glucose, which is the hydrolysate of trehalose, was significantly decreased after silencing SlTres in parasitized S. litura larvae, and the activities of trehalase were also notably reduced. In addition, the cocoon weight, the emergence rate, proportion of normal adults, and the body size of parasitoid offsprings were significantly decreased in SlTre1- or SlTre2-silenced groups compared to the controls. These results implied that parasitization by parasitoids regulated the trehalase of host larvae to create a suitable nutritional environment for the parasitoid offspring. The present study broadens the knowledge of trehalase in the interaction between parasitoids and their hosts and is of benefit to biological control of S. litura acting by parasitoid wasps. Full article
(This article belongs to the Section Insect Molecular Biology and Genomics)
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10 pages, 1310 KiB  
Article
RNA Interference of Chitin Synthase 2 Gene in Liriomyza trifolii through Immersion in Double-Stranded RNA
by Ya-Wen Chang, Yu-Cheng Wang, Yu-Qing Yan, Hong-Fang Xie, Deng-Rong Yuan and Yu-Zhou Du
Insects 2022, 13(9), 832; https://doi.org/10.3390/insects13090832 - 13 Sep 2022
Cited by 6 | Viewed by 1944
Abstract
Liriomyza trifolii is an important invasive pest that infects horticultural vegetables, displaying a strong competitive advantage and showing great potential for inflicting harm. Chitin synthase is one of the key enzymes in insect chitin metabolism and plays an important role in insect growth [...] Read more.
Liriomyza trifolii is an important invasive pest that infects horticultural vegetables, displaying a strong competitive advantage and showing great potential for inflicting harm. Chitin synthase is one of the key enzymes in insect chitin metabolism and plays an important role in insect growth and development. In this study, a chitin synthase (CHS) transcript of L. trifolii was cloned, and the results showed that LtCHS belongs to the CHS2 family. The expression analysis indicated the presence of the highest abundance of LtCHS2 in the pupae at different developmental stages but showed no significant difference among different tissues in the adult. Furthermore, a dsRNA immersion method was developed for RNA interference (RNAi) in L. trifolii using LtCHS2 transcript. RNAi can significantly reduce the expression of LtCHS2 in pupae, and the emergence rate of the pupae was significantly lower than that of the control. The results provide a theoretical basis for exploring the role of chitin synthase gene in L. trifolii and proposing new pest control strategies. Full article
(This article belongs to the Section Insect Molecular Biology and Genomics)
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17 pages, 384 KiB  
Review
Nutritional Composition of Black Soldier Fly Larvae (Hermetia illucens L.) and Its Potential Uses as Alternative Protein Sources in Animal Diets: A Review
by Shengyong Lu, Nittaya Taethaisong, Weerada Meethip, Jariya Surakhunthod, Boontum Sinpru, Thakun Sroichak, Pawinee Archa, Sorasak Thongpea, Siwaporn Paengkoum, Rayudika Aprilia Patindra Purba and Pramote Paengkoum
Insects 2022, 13(9), 831; https://doi.org/10.3390/insects13090831 - 13 Sep 2022
Cited by 111 | Viewed by 20664
Abstract
The rapidly growing population has increased demand for protein quantities and, following a shortage of plant-based feed protein sources and the prohibition of animal-based feed protein, has forced the search for new sources of protein. Therefore, humans have turned their attention to edible [...] Read more.
The rapidly growing population has increased demand for protein quantities and, following a shortage of plant-based feed protein sources and the prohibition of animal-based feed protein, has forced the search for new sources of protein. Therefore, humans have turned their attention to edible insects. Black soldier fly larvae (BSFL) (Hermetia illucens L.) are rich in nutrients such as fat, protein and high-quality amino acids and minerals, making them a good source of protein. Furthermore, BSFL are easily reared and propagated on any nutrient substrate such as plant residues, animal manure and waste, food scraps, agricultural byproducts, or straw. Although BSFL cannot completely replace soybean meal in poultry diets, supplementation of less than 20% has no negative impact on chicken growth performance, biochemical indicators and meat quality. In pig studies, although BSFL supplementation did not have any negative effect on growth performance and meat quality, the feed conversion ratio (FCR) was reduced. There is obviously less research on the feeding of BSFL in pigs than in poultry, particularly in relation to weaning piglets and fattening pigs; further research is needed on the supplementation level of sows. Moreover, it has not been found that BSFL are used in ruminants, and the next phase of research could therefore study them. The use of BSFL in animal feed presents some challenges in terms of cost, availability and legal and consumer acceptance. However, this should be considered in the context of the current shortage of protein feed and the nutritional value of BSFL, which has important research significance in animal production. Full article
10 pages, 272 KiB  
Article
Toxicities and Cross-Resistance of Imidacloprid, Acetamiprid, Emamectin Benzoate, Spirotetramat, and Indoxacarb in Field Populations of Culex quinquefasciatus (Diptera: Culicidae)
by Muhammad Kamran, Sarfraz Ali Shad, Muhammad Binyameen, Naeem Abbas, Muhammad Anees, Rizwan Mustafa Shah and Abdulwahab M. Hafez
Insects 2022, 13(9), 830; https://doi.org/10.3390/insects13090830 - 13 Sep 2022
Cited by 2 | Viewed by 2405
Abstract
Culex quinquefasciatus is a major vector of several pathogens and is capable of breeding in various aquatic habitats. The extensive and injudicious use of synthetic chemicals against the mosquito species has led to the problem of insecticide resistance. To explore this resistance in [...] Read more.
Culex quinquefasciatus is a major vector of several pathogens and is capable of breeding in various aquatic habitats. The extensive and injudicious use of synthetic chemicals against the mosquito species has led to the problem of insecticide resistance. To explore this resistance in detail, toxicity bioassays of imidacloprid, acetamiprid, emamectin benzoate, spirotetramat, and indoxacarb were performed on five Cx. quinquefasciatus field populations from Pakistan in addition to a laboratory susceptible strain. Compared with the susceptible strain, results for the five Cx. quinquefasciatus field populations were as follows: susceptibility to high resistance against imidacloprid (resistance ratio (RR): 0.09–11.18), susceptibility to moderate resistance against acetamiprid (RR: 0.39–8.00), susceptibility to emamectin benzoate (RR: 0.002–0.020), susceptibility to spirotetramat (RR: 0.01–0.07), and low to high resistance against indoxacarb (RR: 3.00–118.00). Correlation analyses revealed a significant positive correlation between imidacloprid, acetamiprid, and spirotetramat median lethal concentration (LC50) values, indicating the possibility of cross-resistance. In contrast, there were no significant correlations between the LC50 values of other tested insecticides, indicating the possible absence of cross-resistance. These results can assist public health authorities, medical entomologists, and pest managers to manage the insecticide resistance of Cx. quinquefasciatus as well as the associated pollution and human health issues. Full article
(This article belongs to the Special Issue Controlling Mosquitoes to Reduce the Spread of Mosquito-Borne Diseases)
12 pages, 1864 KiB  
Article
Annual Fluctuations in Winter Colony Losses of Apis mellifera L. Are Predicted by Honey Flow Dynamics of the Preceding Year
by Jes Johannesen, Saskia Wöhl, Stefen Berg and Christoph Otten
Insects 2022, 13(9), 829; https://doi.org/10.3390/insects13090829 - 12 Sep 2022
Cited by 7 | Viewed by 2513
Abstract
Winter loss rates of honey bee colonies may fluctuate highly between years in temperate climates. The present study combined survey data of autumn and winter loss rates in Germany (2012–2021) with estimates of honey flow—assessed with automated hive scales as the start of [...] Read more.
Winter loss rates of honey bee colonies may fluctuate highly between years in temperate climates. The present study combined survey data of autumn and winter loss rates in Germany (2012–2021) with estimates of honey flow—assessed with automated hive scales as the start of honey flow in spring and its magnitude in summer—with the aim of understanding annual fluctuations in loss rates. Autumn colony loss rates were positively and significantly correlated with winter loss rates, whereas winter loss rates were inversely related to loss rates in autumn of the following year. An early start of net honey flow in spring predicted high loss rates in both autumn and winter, whereas high cumulative honey flow led to lower loss rates. The start of net honey flow was related to temperature sums in March. Combined, the results implied that the winter loss rate in one year was influenced by the loss rate of the preceding winter and shaped by honey flow dynamics during the following year. Hence, the rate of colony loss in winter can be viewed as a cumulative death process affected by the preceding one and a half years. Full article
(This article belongs to the Special Issue Losses of Honey Bee Colonies across the World)
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14 pages, 20420 KiB  
Article
The First Representative of the Roachoid Family Spiloblattinidae (Insecta, Dictyoptera) from the Late Pennsylvanian of the Iberian Peninsula
by André Nel, Artai A. Santos, Antonio Hernández-Orúe, Torsten Wappler, José B. Diez and Enrique Peñalver
Insects 2022, 13(9), 828; https://doi.org/10.3390/insects13090828 - 12 Sep 2022
Cited by 4 | Viewed by 1907
Abstract
Sysciophlebia ‘sp. form Villablino’, the first Iberian representative of the Palaeozoic–Early Mesozoic family Spiloblattinidae, is described and illustrated. Its forewing colour pattern is strongly similar to those of the Gzhelian–early-middle Asselian species Sysciophlebia euglyptica, Sysciophlebia ilfeldensis, Sysciophlebia rubida, and ‘ [...] Read more.
Sysciophlebia ‘sp. form Villablino’, the first Iberian representative of the Palaeozoic–Early Mesozoic family Spiloblattinidae, is described and illustrated. Its forewing colour pattern is strongly similar to those of the Gzhelian–early-middle Asselian species Sysciophlebia euglyptica, Sysciophlebia ilfeldensis, Sysciophlebia rubida, and ‘Sysciophlebia sp. form KBQ’, supporting the currently proposed Gzhelian age for its type locality. It supports the use of the representatives of the Spiloblattinidae for stratigraphic purposes. The diagnoses and limits of the families Subioblattidae, Phyloblattidae, Compsoblattidae, Spiloblattinidae, and of the spiloblattinid genera are discussed. Full article
(This article belongs to the Special Issue Fossil Insects: From Carboniferous to Quaternary)
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10 pages, 1128 KiB  
Article
Effect of Parental Age and Mating Status on Reproductive Performance of Orius laevigatus (Hemiptera: Anthocoridae)
by Amador Rodríguez-Gómez, Virginia Balanza, Alberto Donate, Ana Belén Abelaira, María del Carmen Reche, Isabel Sánchez-Martínez and Pablo Bielza
Insects 2022, 13(9), 827; https://doi.org/10.3390/insects13090827 - 12 Sep 2022
Cited by 2 | Viewed by 1809
Abstract
The reproductive potential of biological control agents (BCAs) is crucial for efficient mass-rearing and field performance, and it all begins with mating. Fecundity can be strongly influenced by intrinsic conditions, such as female age and, often neglected, male age and mating status. However, [...] Read more.
The reproductive potential of biological control agents (BCAs) is crucial for efficient mass-rearing and field performance, and it all begins with mating. Fecundity can be strongly influenced by intrinsic conditions, such as female age and, often neglected, male age and mating status. However, little is known about the impact of parental status at mating on female reproductive outcomes in BCAs. Orius laevigatus (Fieber) (Hemiptera: Anthocoridae) is widely used to control thrips in protected crops. We evaluated how many consecutive females a male could successfully mate and the effect on a female’s reproductive output. In addition, we studied the effects of male and female age on mating. In the multiple mating experiment, the males showed a high capacity to fertilize females successively, not reducing fecundity until the sixth mated female. In the delayed mating experiment, copulation duration and fecundity increased with male age but decreased with female age. In contrast, fertility followed an opposite pattern, increasing with female age but decreasing with male age. However, fecundity gains outweighed fertility declines in both sexes. Therefore, reproductive capacity is increased when mating newly emerged females with males a few days old. The implications of our results for mass rearing and field performance are discussed. Full article
(This article belongs to the Collection Hemiptera: Ecology, Physiology, and Economic Importance)
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