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Editor’s Choice Articles

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

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18 pages, 8224 KiB  
Article
Floral Volatile Organic Compounds and a List of Pollinators of Fallopia baldschuanica (Polygonaceae)
by Anna Jakubska-Busse, Mariusz Dziadas, Iwona Gruss and Michał J. Kobyłka
Insects 2022, 13(10), 904; https://doi.org/10.3390/insects13100904 - 5 Oct 2022
Cited by 4 | Viewed by 3596
Abstract
Fallopia baldschuanica (Polygonaceae) is an Asian plant growing wild in parts of Europe and North and Central America as an introduced taxon, in many countries it is considered a potentially invasive species. This article presents the list of 18 volatile organic compounds (VOCs) [...] Read more.
Fallopia baldschuanica (Polygonaceae) is an Asian plant growing wild in parts of Europe and North and Central America as an introduced taxon, in many countries it is considered a potentially invasive species. This article presents the list of 18 volatile organic compounds (VOCs) emitted by the flowers of F. baldchuanica and identified by headspace gas chromatography/mass spectrometry (HS-GC/MS) analyzes, and a list of flower-visiting and pollinating insects that have been observed in the city center of Wrocław (SW Poland). β-ocimene, heptanal, nonanal, α-pinene, 3-thujene, and limonene, were detected as the floral scent’s most important aroma compounds. F. baldschuanica also produces the aphid alarm pheromones, i.e., β-farnesene and limonene, that repels aphids. Additionally, the pollinators of F. baldschuanica were indicated, based on two years of observations in five sites in the urban area. It was found, that the pollinators of this plant with the highest species stability are: Diptera from families Syrphidae (Chrysotoxum bicinctum, Eristalis pertinax, Eupeodes corollae, Episyrphus balteatus, Eristalis tenax, Syrphus ribesii, Eristalis intricaria), Muscidae (Musca domestica), Sarcophagidae (Sarcophaga spp.), Calliphoridae (Lucilia sericata, Lucilia caesar), Hymenoptera from families Vespidae (Vespula vulgaris), and Apidae (Apis sp., Bombus sp.). The key role of VOCs in adaptation to plant expansion is discussed. Full article
(This article belongs to the Special Issue Physical and Chemical Interactions between Insects and Plants)
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18 pages, 2338 KiB  
Article
Effects of a Mealworm (Tenebrio molitor) Extract on Metabolic Syndrome-Related Pathologies: In Vitro Insulin Sensitivity, Inflammatory Response, Hypolipidemic Activity and Oxidative Stress
by Joaquín Navarro del Hierro, Emma Cantero-Bahillo, M. Teresa Fernández-Felipe, Mónica R. García-Risco, Tiziana Fornari, Patricia Rada, Laura Doblado, Vitor Ferreira, Ana B. Hitos, Ángela M. Valverde, María Monsalve and Diana Martin
Insects 2022, 13(10), 896; https://doi.org/10.3390/insects13100896 - 30 Sep 2022
Cited by 11 | Viewed by 4390
Abstract
The mealworm (Tenebrio molitor Linnaeus 1758) is gaining importance as one of the most popular edible insects. Studies focusing on its bioactivities are increasing, although alternative forms of consumption other than the whole insect or flour, such as bioactive non-protein extracts, remain underexplored. [...] Read more.
The mealworm (Tenebrio molitor Linnaeus 1758) is gaining importance as one of the most popular edible insects. Studies focusing on its bioactivities are increasing, although alternative forms of consumption other than the whole insect or flour, such as bioactive non-protein extracts, remain underexplored. Furthermore, the incidence of metabolic syndrome-related pathologies keeps increasing, hence the importance of seeking novel natural sources for reducing the impact of certain risk factors. The aim was to study the potential of a non-protein mealworm extract on metabolic syndrome-related pathologies, obtained with ethanol:water (1:1, v/v) by ultrasound-assisted extraction. We characterized the extract by gas-chromatography mass-spectrometry and assessed its hypolipidemic potential, its ability to scavenger free radicals, to attenuate the inflammatory response in microglial cells, to affect mitochondrial respiration and to enhance insulin sensitivity in mouse hepatocytes. The extract contained fatty acids, monoglycerides, amino acids, certain acids and sugars. The mealworm extract caused a 30% pancreatic lipase inhibition, 80% DPPH· scavenging activity and 55.9% reduction in the bioaccessibility of cholesterol (p = 0.009). The extract was effective in decreasing iNOS levels, increasing basal, maximal and ATP coupled respiration as well as enhancing insulin-mediated AKT phosphorylation at low insulin concentrations (p < 0.05). The potential of a non-protein bioactive mealworm extract against metabolic syndrome-related pathologies is shown, although further studies are needed to elucidate the mechanisms and relationship with compounds. Full article
(This article belongs to the Special Issue Insects as Food and Feed: Opportunities and Risks)
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10 pages, 907 KiB  
Article
Meta-Analysis of Transcriptomes in Insects Showing Density-Dependent Polyphenism
by Kouhei Toga, Kakeru Yokoi and Hidemasa Bono
Insects 2022, 13(10), 864; https://doi.org/10.3390/insects13100864 - 23 Sep 2022
Cited by 5 | Viewed by 7522
Abstract
With increasing public data, a statistical analysis approach called meta-analysis, which combines transcriptome results obtained from multiple studies, has succeeded in providing novel insights into targeted biological processes. Locusts and aphids are representative of insect groups that exhibit density-dependent plasticity. Although the physiological [...] Read more.
With increasing public data, a statistical analysis approach called meta-analysis, which combines transcriptome results obtained from multiple studies, has succeeded in providing novel insights into targeted biological processes. Locusts and aphids are representative of insect groups that exhibit density-dependent plasticity. Although the physiological mechanisms underlying density-dependent polyphenism have been identified in aphids and locusts, the underlying molecular mechanisms remain largely unknown. In this study, we performed a meta-analysis of public transcriptomes to gain additional insights into the molecular underpinning of density-dependent plasticity. We collected RNA sequencing data of aphids and locusts from public databases and detected differentially expressed genes (DEGs) between crowded and isolated conditions. Gene set enrichment analysis was performed to reveal the characteristics of the DEGs. DNA replication (GO:0006260), DNA metabolic processes (GO:0006259), and mitotic cell cycle (GO:0000278) were enriched in response to crowded conditions. To date, these processes have scarcely been the focus of research. The importance of the oxidative stress response and neurological system modifications under isolated conditions has been highlighted. These biological processes, clarified by meta-analysis, are thought to play key roles in the regulation of density-dependent plasticity. Full article
(This article belongs to the Special Issue Insect Genome and Transcriptome Data)
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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 45 | Viewed by 8692
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 Collection Integrated Pest Management in Agricultural Crops and Forest Ecosystems)
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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 16 | Viewed by 9523
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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27 pages, 1543 KiB  
Review
Synanthropic Flies—A Review Including How They Obtain Nutrients, along with Pathogens, Store Them in the Crop and Mechanisms of Transmission
by John G. Stoffolano, Jr.
Insects 2022, 13(9), 776; https://doi.org/10.3390/insects13090776 - 27 Aug 2022
Cited by 4 | Viewed by 10263
Abstract
An attempt has been made to provide a broad review of synanthropic flies and, not just a survey of their involvement in human pathogen transmission. It also emphasizes that the crop organ of calliphorids, sarcophagids, and muscids was an evolutionary development and has [...] Read more.
An attempt has been made to provide a broad review of synanthropic flies and, not just a survey of their involvement in human pathogen transmission. It also emphasizes that the crop organ of calliphorids, sarcophagids, and muscids was an evolutionary development and has served and assisted non-blood feeding flies in obtaining food, as well as pathogens, prior to the origin of humans. Insects are believed to be present on earth about 400 million years ago (MYA). Thus, prior to the origin of primates, there was adequate time for these flies to become associated with various animals and to serve as important transmitters of pathogens associated with them prior to the advent of early hominids and modern humans. Through the process of fly crop regurgitation, numerous pathogens are still readily being made available to primates and other animals. Several studies using invertebrate-derived DNA = iDNA meta-techniques have been able to identify, not only the source the fly had fed on, but also if it had fed on their feces or the animal's body fluids. Since these flies are known to feed on both vertebrate fluids (i.e., from wounds, saliva, mucus, or tears), as well as those of other animals, and their feces, identification of the reservoir host, amplification hosts, and associated pathogens is essential in identifying emerging infectious diseases. New molecular tools, along with a focus on the crop, and what is in it, should provide a better understanding and development of whether these flies are involved in emerging infectious diseases. If so, epidemiological models in the future might be better at predicting future epidemics or pandemics. Full article
(This article belongs to the Special Issue Biology, Ecology and Control of Synanthropic Flies)
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18 pages, 1389 KiB  
Review
Drosophila Glue: A Promising Model for Bioadhesion
by Manon Monier and Virginie Courtier-Orgogozo
Insects 2022, 13(8), 734; https://doi.org/10.3390/insects13080734 - 16 Aug 2022
Cited by 6 | Viewed by 4839
Abstract
The glue produced by Drosophila larvae to attach themselves to a substrate for several days and resist predation until the end of metamorphosis represents an attractive model to develop new adhesives for dry environments. The adhesive properties of this interesting material have been [...] Read more.
The glue produced by Drosophila larvae to attach themselves to a substrate for several days and resist predation until the end of metamorphosis represents an attractive model to develop new adhesives for dry environments. The adhesive properties of this interesting material have been investigated recently, and it was found that it binds as well as strongly adhesive commercial tapes to various types of substrates. This glue hardens rapidly after excretion and is made of several proteins. In D. melanogaster, eight glue proteins have been identified: four are long glycosylated mucoproteins containing repeats rich in prolines, serines and threonines, and four others are shorter proteins rich in cysteines. This protein mix is produced by the salivary glands through a complex packaging process that is starting to be elucidated. Drosophila species have adapted to stick to various substrates in diverse environmental conditions and glue genes appear to evolve rapidly in terms of gene number, number of repeats and sequence of the repeat motifs. Interestingly, besides its adhesive properties, the glue may also have antimicrobial activities. We discuss future perspectives and avenues of research for the development of new bioadhesives mimicking Drosophila fly glue. Full article
(This article belongs to the Special Issue Contributions of Women in Insect Science)
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15 pages, 14914 KiB  
Article
Artificial Nesting Hills Promote Wild Bees in Agricultural Landscapes
by Ulrich Neumüller, Hannah Burger, Antonia V. Mayr, Sebastian Hopfenmüller, Sabrina Krausch, Nadine Herwig, Ronald Burger, Olaf Diestelhorst, Katrin Emmerich, Mare Haider, Manuel Kiefer, Jonas Konicek, Johann-Christoph Kornmilch, Marina Moser, Christoph Saure, Arno Schanowski, Erwin Scheuchl, Julia Sing, Max Wagner, Julia Witter, Hans R. Schwenninger and Manfred Ayasseadd Show full author list remove Hide full author list
Insects 2022, 13(8), 726; https://doi.org/10.3390/insects13080726 - 14 Aug 2022
Cited by 8 | Viewed by 5987
Abstract
The availability of nesting resources influences the persistence and survival of bee communities. Although a positive effect of artificial nesting structures has frequently been shown for aboveground cavity-nesting wild bees, studies on below ground-nesting bees are rare. Artificial nesting hills designed to provide [...] Read more.
The availability of nesting resources influences the persistence and survival of bee communities. Although a positive effect of artificial nesting structures has frequently been shown for aboveground cavity-nesting wild bees, studies on below ground-nesting bees are rare. Artificial nesting hills designed to provide nesting habitats for ground-nesting bees were therefore established within the BienABest project in 20 regions across Germany. Wild bee communities were monitored for two consecutive years, accompanied by recordings of landscape and abiotic nest site variables. Bee activity and species richness increased from the first to the second year after establishment; this was particularly pronounced in landscapes with a low cover of semi-natural habitat. The nesting hills were successively colonized, indicating that they should exist for many years, thereby promoting a species-rich bee community. We recommend the construction of nesting hills on sun-exposed sites with a high thermal gain of the substrate because the bees prefer south-facing sites with high soil temperatures. Although the soil composition of the nesting hills plays a minor role, we suggest using local soil to match the needs of the local bee community. We conclude that artificial nesting structures for ground-nesting bees act as a valuable nesting resource for various bee species, particularly in highly degraded landscapes. We offer a construction and maintenance guide for the successful establishment of nesting hills for bee conservation. Full article
(This article belongs to the Special Issue Advances in the Use of Hymenoptera as Bioindicators in Agricultural Landscapes)
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11 pages, 7570 KiB  
Article
Mechanical Acaricides Active against the Blacklegged Tick, Ixodes scapularis
by Elise A. Richardson, Loganathan Ponnusamy and R. Michael Roe
Insects 2022, 13(8), 672; https://doi.org/10.3390/insects13080672 - 26 Jul 2022
Cited by 7 | Viewed by 3883
Abstract
Cases of Lyme disease in humans are on the rise in the United States and Canada. The vector of the bacteria that causes this disease is the blacklegged tick, Ixodes scapularis. Current control methods for I. scapularis mainly involve chemical acaricides. Unfortunately, [...] Read more.
Cases of Lyme disease in humans are on the rise in the United States and Canada. The vector of the bacteria that causes this disease is the blacklegged tick, Ixodes scapularis. Current control methods for I. scapularis mainly involve chemical acaricides. Unfortunately, ticks are developing resistance to these chemicals, and more and more, the public prefers non-toxic alternatives to chemical pesticides. We discovered that volcanic glass, ImergardTM WP, and other industrial minerals such as Celite 610 were efficacious mechanical insecticides against mosquitoes, filth flies, and agricultural pests. In this report, when 6–10- and 50–70-day old unfed I. scapularis nymphs were dipped for 1–2 s into Celite, the time to 50% mortality (LT50) was 66.8 and 81.7 min, respectively, at 30 °C and 50% relative humidity (RH). The LT50 was actually shorter at a higher 70% RH, 43.8 min. Scanning electron microscopy showed that the ticks were coated over most of their body surface, including partial to almost total coverage of the opening to their respiratory system. The other mechanical insecticide, Imergard, had similar efficacy against blacklegged unfed nymphs with an LT50 at 30 °C and 50% RH of 70.4 min. Although more research is needed, this study suggests that industrial minerals could be used as an alternative to chemical pesticides to control ticks and Lyme disease. Full article
(This article belongs to the Section Medical and Livestock Entomology)
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39 pages, 15099 KiB  
Article
Building International Capacity for Citizen Scientist Engagement in Mosquito Surveillance and Mitigation: The GLOBE Program’s GLOBE Observer Mosquito Habitat Mapper
by Russanne D. Low, Theresa G. Schwerin, Rebecca A. Boger, Cassie Soeffing, Peder V. Nelson, Dan Bartlett, Prachi Ingle, Matteo Kimura and Andrew Clark
Insects 2022, 13(7), 624; https://doi.org/10.3390/insects13070624 - 13 Jul 2022
Cited by 11 | Viewed by 5686
Abstract
The GLOBE Program’s GLOBE Observer Mosquito Habitat Mapper is a no-cost citizen scientist data collection tool compatible with Android and iOS devices. Available in 14 languages and 126 countries, it supports mosquito vector surveillance, mitigation, and education by interested individuals and as part [...] Read more.
The GLOBE Program’s GLOBE Observer Mosquito Habitat Mapper is a no-cost citizen scientist data collection tool compatible with Android and iOS devices. Available in 14 languages and 126 countries, it supports mosquito vector surveillance, mitigation, and education by interested individuals and as part of participatory community surveillance programs. For low-resource communities where mosquito control services are inadequate, the Mosquito Habitat Mapper supports local health action, empowerment, and environmental justice. The tangible benefits to human health supported by the Mosquito Habitat Mapper have encouraged its wide adoption, with more than 32,000 observations submitted from 84 countries. The Mosquito Habitat Mapper surveillance and data collection tool is complemented by an open database, a map visualization interface, data processing and analysis tools, and a supporting education and outreach campaign. The mobile app tool and associated research and education assets can be rapidly deployed in the event of a pandemic or local disease outbreak, contributing to global readiness and resilience in the face of mosquito-borne disease. Here, we describe the app, the Mosquito Habitat Mapper information system, examples of Mosquito Habitat Mapper deployment in scientific research, and the outreach campaign that supports volunteer training and STEM education of students worldwide. Full article
(This article belongs to the Special Issue Citizen Science Approaches to Vector Surveillance)
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14 pages, 1191 KiB  
Article
Systematic Functional Annotation Workflow for Insects
by Hidemasa Bono, Takuma Sakamoto, Takeya Kasukawa and Hiroko Tabunoki
Insects 2022, 13(7), 586; https://doi.org/10.3390/insects13070586 - 27 Jun 2022
Cited by 9 | Viewed by 6242
Abstract
Next-generation sequencing has revolutionized entomological study, rendering it possible to analyze the genomes and transcriptomes of non-model insects. However, use of this technology is often limited to obtaining the nucleotide sequences of target or related genes, with many of the acquired sequences remaining [...] Read more.
Next-generation sequencing has revolutionized entomological study, rendering it possible to analyze the genomes and transcriptomes of non-model insects. However, use of this technology is often limited to obtaining the nucleotide sequences of target or related genes, with many of the acquired sequences remaining unused because other available sequences are not sufficiently annotated. To address this issue, we have developed a functional annotation workflow for transcriptome-sequenced insects to determine transcript descriptions, which represents a significant improvement over the previous method (functional annotation pipeline for insects). The developed workflow attempts to annotate not only the protein sequences obtained from transcriptome analysis but also the ncRNA sequences obtained simultaneously. In addition, the workflow integrates the expression-level information obtained from transcriptome sequencing for application as functional annotation information. Using the workflow, functional annotation was performed on the sequences obtained from transcriptome sequencing of the stick insect (Entoria okinawaensis) and silkworm (Bombyx mori), yielding richer functional annotation information than that obtained in our previous study. The improved workflow allows the more comprehensive exploitation of transcriptome data and is applicable to other insects because the workflow has been openly developed on GitHub. Full article
(This article belongs to the Special Issue Insect Genome and Transcriptome Data)
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13 pages, 573 KiB  
Review
The Role of Insect Symbiotic Bacteria in Metabolizing Phytochemicals and Agrochemicals
by Man Zhao, Xingyu Lin and Xianru Guo
Insects 2022, 13(7), 583; https://doi.org/10.3390/insects13070583 - 26 Jun 2022
Cited by 33 | Viewed by 5335
Abstract
The diversity and high adaptability of insects are heavily associated with their symbiotic microbes, which include bacteria, fungi, viruses, protozoa, and archaea. These microbes play important roles in many aspects of the biology and physiology of insects, such as helping the host insects [...] Read more.
The diversity and high adaptability of insects are heavily associated with their symbiotic microbes, which include bacteria, fungi, viruses, protozoa, and archaea. These microbes play important roles in many aspects of the biology and physiology of insects, such as helping the host insects with food digestion, nutrition absorption, strengthening immunity and confronting plant defenses. To maintain normal development and population reproduction, herbivorous insects have developed strategies to detoxify the substances to which they may be exposed in the living habitat, such as the detoxifying enzymes carboxylesterase, glutathione-S-transferases (GSTs), and cytochrome P450 monooxygenases (CYP450s). Additionally, insect symbiotic bacteria can act as an important factor to modulate the adaptability of insects to the exposed detrimental substances. This review summarizes the current research progress on the role of insect symbiotic bacteria in metabolizing phytochemicals and agrochemicals (insecticides and herbicides). Given the importance of insect microbiota, more functional symbiotic bacteria that modulate the adaptability of insects to the detrimental substances to which they are exposed should be identified, and the underlying mechanisms should also be further studied, facilitating the development of microbial-resource-based pest control approaches or protective methods for beneficial insects. Full article
(This article belongs to the Special Issue Insect Microbiome and Immunity)
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21 pages, 1092 KiB  
Review
Deciphering the Biological Enigma—Genomic Evolution Underlying Anhydrobiosis in the Phylum Tardigrada and the Chironomid Polypedilum vanderplanki
by Yuki Yoshida and Sae Tanaka
Insects 2022, 13(6), 557; https://doi.org/10.3390/insects13060557 - 19 Jun 2022
Cited by 8 | Viewed by 4838
Abstract
Anhydrobiosis, an ametabolic dehydrated state triggered by water loss, is observed in several invertebrate lineages. Anhydrobiotes revive when rehydrated, and seem not to suffer the ultimately lethal cell damage that results from severe loss of water in other organisms. Here, we review the [...] Read more.
Anhydrobiosis, an ametabolic dehydrated state triggered by water loss, is observed in several invertebrate lineages. Anhydrobiotes revive when rehydrated, and seem not to suffer the ultimately lethal cell damage that results from severe loss of water in other organisms. Here, we review the biochemical and genomic evidence that has revealed the protectant molecules, repair systems, and maintenance pathways associated with anhydrobiosis. We then introduce two lineages in which anhydrobiosis has evolved independently: Tardigrada, where anhydrobiosis characterizes many species within the phylum, and the genus Polypedilum, where anhydrobiosis occurs in only two species. Finally, we discuss the complexity of the evolution of anhydrobiosis within invertebrates based on current knowledge, and propose perspectives to enhance the understanding of anhydrobiosis. Full article
(This article belongs to the Special Issue The Adaptations of Arthropods to Extreme Environments)
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14 pages, 3378 KiB  
Article
Exploring Honeybee Abdominal Anatomy through Micro-CT and Novel Multi-Staining Approaches
by Jessica Carreira De Paula, Kevin Doello, Cristina Mesas, Garyfalia Kapravelou, Alberto Cornet-Gómez, Francisco José Orantes, Rosario Martínez, Fátima Linares, Jose Carlos Prados, Jesus María Porres, Antonio Osuna and Luis Miguel de Pablos
Insects 2022, 13(6), 556; https://doi.org/10.3390/insects13060556 - 18 Jun 2022
Cited by 8 | Viewed by 5522
Abstract
Continuous improvements in morphological and histochemical analyses of Apis mellifera could improve our understanding of the anatomy and physiology of these insects at both the cellular and tissue level. In this work, two different approaches have been performed to add new data on [...] Read more.
Continuous improvements in morphological and histochemical analyses of Apis mellifera could improve our understanding of the anatomy and physiology of these insects at both the cellular and tissue level. In this work, two different approaches have been performed to add new data on the abdomen of worker bees: (i) Micro-computed tomography (Micro-CT), which allows the identification of small-scale structures (micrometers) with adequate/optimal resolution and avoids sample damage and, (ii) histochemical multi-staining with Periodic Acid-Schiff-Alcian blue, Lactophenol-Saphranin O and pentachrome staining to precisely characterize the histological structures of the midgut and hindgut. Micro-CT allowed high-resolution imaging of anatomical structures of the honeybee abdomen with particular emphasis on the proventriculus and pyloric valves, as well as the connection of the sting apparatus with the terminal abdominal ganglia. Furthermore, the histochemical analyses have allowed for the first-time description of ventricular telocytes in honeybees, a cell type located underneath the midgut epithelium characterized by thin and long cytoplasmic projections called telopodes. Overall, the analysis of these images could help the detailed anatomical description of the cryptic structures of honeybees and also the characterization of changes due to abiotic or biotic stress conditions. Full article
(This article belongs to the Section Insect Physiology, Reproduction and Development)
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23 pages, 2147 KiB  
Article
Reviewing the WHO Tube Bioassay Methodology: Accurate Method Reporting and Numbers of Mosquitoes Are Key to Producing Robust Results
by Giorgio Praulins, Daniel P. McDermott, Angus Spiers and Rosemary Susan Lees
Insects 2022, 13(6), 544; https://doi.org/10.3390/insects13060544 - 14 Jun 2022
Cited by 14 | Viewed by 4876
Abstract
Accurately monitoring insecticide resistance in target mosquito populations is important for combating malaria and other vector-borne diseases, and robust methods are key. The “WHO susceptibility bioassay” has been available from the World Health Organization for 60+ years: mosquitoes of known physiological status are [...] Read more.
Accurately monitoring insecticide resistance in target mosquito populations is important for combating malaria and other vector-borne diseases, and robust methods are key. The “WHO susceptibility bioassay” has been available from the World Health Organization for 60+ years: mosquitoes of known physiological status are exposed to a discriminating concentration of insecticide. Several changes to the test procedures have been made historically, which may seem minor but could impact bioassay results. The published test procedures and literature for this method were reviewed for methodological details. Areas where there was room for interpretation in the test procedures or where the test procedures were not being followed were assessed experimentally for their impact on bioassay results: covering or uncovering of the tube end during exposure; the number of mosquitoes per test unit; and mosquito age. Many publications do not cite the most recent test procedures; methodological details are reported which contradict the test procedures referenced, or methodological details are not fully reported. As a result, the precise methodology is unclear. Experimental testing showed that using fewer than the recommended 15–30 mosquitoes per test unit significantly reduced mortality, covering the exposure tube had no significant effect, and using mosquitoes older than 2–5 days old increased mortality, particularly in the resistant strain. Recommendations are made for improved reporting of experimental parameters Full article
(This article belongs to the Special Issue Insecticides for Mosquito Control: Strengthening the Evidence Base)
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15 pages, 1465 KiB  
Article
Technological Performance of Cricket Powder (Acheta domesticus L.) in Wheat-Based Formulations
by Andrea Bresciani, Gaetano Cardone, Costanza Jucker, Sara Savoldelli and Alessandra Marti
Insects 2022, 13(6), 546; https://doi.org/10.3390/insects13060546 - 14 Jun 2022
Cited by 28 | Viewed by 4369
Abstract
The recent socio-economic situation requires producers to change the composition of basic foods. The aim of this study was to assess the technological properties of wheat flour enriched with cricket powder (CP) (at 5%, 10%, and 20% levels) for the development of bread [...] Read more.
The recent socio-economic situation requires producers to change the composition of basic foods. The aim of this study was to assess the technological properties of wheat flour enriched with cricket powder (CP) (at 5%, 10%, and 20% levels) for the development of bread and pasta. The hydration (i.e., water absorption capacity, oil absorption capacity, water absorption index, water solubility index, and swelling power), foaming (i.e., foaming capacity and stability),emulsifying (emulsifying activity and emulsion stability), and rheological (during gluten aggregation, mixing, extension, and leavening) properties were investigated. Finally, bread and fresh pasta were prepared and characterized. Emulsifying activity, stability, and foaming capacity decreased in the presence of CP, whereas foaming stability and water solubility increased. The results on dough rheology highlighted the need to increase the amount of water, and to decrease the mixing and leavening time, to keep an acceptable bread volume. Indeed, 10% CP enrichment led to a product characterized by a similar volume and crumb hardness to the control (wheat flour). Despite the decrease in extensibility caused by CP, it was possible to produce fresh pasta enriched with CP, with the best cooking behavior obtained at a 5% replacement level. Full article
(This article belongs to the Collection Edible Insects and Circular Economy)
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16 pages, 12629 KiB  
Article
Microscopic Identification of Anatomical Elements and Chemical Analysis of Secondary Nests of Vespa velutina nigrithorax du Buyson
by Nazaret Crespo, José Louzada, Lisete S. Fernandes, Pedro B. Tavares and José Aranha
Insects 2022, 13(6), 537; https://doi.org/10.3390/insects13060537 - 10 Jun 2022
Cited by 6 | Viewed by 3586
Abstract
Vespa velutina accidentally arrived in Europe (France) in 2004, and rapidly expanded throughout the entire country. Its presence in mainland Portugal was first noticed in 2011. Being an invasive species with no natural predators in the region to control it, it has caused [...] Read more.
Vespa velutina accidentally arrived in Europe (France) in 2004, and rapidly expanded throughout the entire country. Its presence in mainland Portugal was first noticed in 2011. Being an invasive species with no natural predators in the region to control it, it has caused enormous environmental and economic damage, particularly on Apis mellifera (honeybee) colonies. Although there is already some research on this species’ biology, little is known about its adaption to European ecological conditions, specifically in terms of nest building. This type of hornet builds a primary nest in the spring to start a colony. During the summer, they build a secondary nest to develop the main colony. These secondary nests are ovoid-shaped and range in size from 18.7 cm to 45.0 cm in diameter and from 19.2 cm to 65.0 cm in length, attaining their highest development in late summer. The external appearance of these nests is characterized by alternating stripes that are beige and brown in color. The main objective of this study is to identify the composition and the origin of the materials that are used by Vespa velutina nigrithorax to build the outer envelope of these secondary nests. This information could be very interesting and will not only increase our knowledge on the biology of the species in regions far from its original area, but will also be relevant for the future implementation of new policies to control this invasive species by means biological control. Several samples were taken from each nest and were observed under different optical magnifying devices. In the second stage, their chemical composition was analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM/EDS). It was noticed that almost all of the materials used in the nests’ construction were lignocellulose from woody materials from both softwood (gymnosperm) and hardwood (angiosperm) forest species as well from leaves and small particles of agricultural origin (grasses). The beige strips were formed almost exclusively from woody softwood cells, while the brown strips were composed of hardwood cells, leaf tissues, and grasses. Chemically, it was noticed that this material mainly consisted of cellulose, with more than 99% being composed of C and O and very little mineral material from elements such as Na, Al, Si, K, and Ca. The achieved results allow us to state that in the construction of these secondary nests, these hornets only used organic materials that are then probably agglomerated through their mouths. Full article
(This article belongs to the Topic Arthropod Biodiversity: Ecological and Functional Aspects)
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17 pages, 1934 KiB  
Article
Biological Control Options for the Golden Twin-Spot Moth, Chrysodeixis chalcites (Esper) (Lepidoptera: Noctuidae) in Banana Crops of the Canary Islands
by Modesto del Pino, Tomás Cabello and Estrella Hernández-Suárez
Insects 2022, 13(6), 516; https://doi.org/10.3390/insects13060516 - 31 May 2022
Cited by 2 | Viewed by 3122
Abstract
Chrysodeixis chalcites (Esper) (Lepidoptera: Noctuidae) is a significant pest in banana plantations in the Canary Islands. Field surveys were carried out to identify its naturally occurring parasitoids and estimate their parasitism rates between September 2007 and October 2010. Ch. chalcites was parasitized by [...] Read more.
Chrysodeixis chalcites (Esper) (Lepidoptera: Noctuidae) is a significant pest in banana plantations in the Canary Islands. Field surveys were carried out to identify its naturally occurring parasitoids and estimate their parasitism rates between September 2007 and October 2010. Ch. chalcites was parasitized by six different larval/pupal parasitoid species: Cotesia sp., C. glomerata L. (Hym.: Braconidae), Aplomyia confinis Fallén (Dip.: Tachinidae), Hyposoter rufiventris Perez, Ctenochares bicolorus L. (Hym.: Ichneumonidae) and Aleiodes sp. (Hym.: Braconidae). Among them, Cotesia sp. was the most frequent species, accounting for 8.18% of parasitized larvae. High levels of egg parasitism were detected, with Trichogramma achaeae Nagaraja and Nagarkatti (Hym.: Trichogrammatidae) being the most widely distributed egg parasitoid. A greenhouse assay was also carried out on a commercial banana crop with the aim of evaluating the potential of T. achaeae as a biological control agent and compared with a chemical control. Five periodic inundative releases of 35 adults/m2 every 21 days were necessary to achieve an adequate parasitism level (56.25 ± 1.61%). Moreover, there was 15.75% less foliar damage in the biological control plot compared to the chemical control plot. These results indicate that T. achaeae could be a promising biocontrol agent of Ch. chalcites in greenhouse banana crops. Full article
(This article belongs to the Topic Integrated Pest Management of Crops)
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20 pages, 796 KiB  
Review
All for One Health and One Health for All: Considerations for Successful Citizen Science Projects Conducting Vector Surveillance from Animal Hosts
by Karen C. Poh, Jesse R. Evans, Michael J. Skvarla and Erika T. Machtinger
Insects 2022, 13(6), 492; https://doi.org/10.3390/insects13060492 - 24 May 2022
Cited by 8 | Viewed by 5222
Abstract
Many vector-borne diseases that affect humans are zoonotic, often involving some animal host amplifying the pathogen and infecting an arthropod vector, followed by pathogen spillover into the human population via the bite of the infected vector. As urbanization, globalization, travel, and trade continue [...] Read more.
Many vector-borne diseases that affect humans are zoonotic, often involving some animal host amplifying the pathogen and infecting an arthropod vector, followed by pathogen spillover into the human population via the bite of the infected vector. As urbanization, globalization, travel, and trade continue to increase, so does the risk posed by vector-borne diseases and spillover events. With the introduction of new vectors and potential pathogens as well as range expansions of native vectors, it is vital to conduct vector and vector-borne disease surveillance. Traditional surveillance methods can be time-consuming and labor-intensive, especially when surveillance involves sampling from animals. In order to monitor for potential vector-borne disease threats, researchers have turned to the public to help with data collection. To address vector-borne disease and animal conservation needs, we conducted a literature review of studies from the United States and Canada utilizing citizen science efforts to collect arthropods of public health and veterinary interest from animals. We identified common stakeholder groups, the types of surveillance that are common with each group, and the literature gaps on understudied vectors and populations. From this review, we synthesized considerations for future research projects involving citizen scientist collection of arthropods that affect humans and animals. Full article
(This article belongs to the Special Issue Citizen Science Approaches to Vector Surveillance)
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15 pages, 2834 KiB  
Review
Coconut Rhinoceros Beetle in Samoa: Review of a Century-Old Invasion and Prospects for Control in a Changing Future
by Sulav Paudel, Sean D. G. Marshall, Nicola K. Richards, George Hazelman, Pueata Tanielu and Trevor A. Jackson
Insects 2022, 13(5), 487; https://doi.org/10.3390/insects13050487 - 23 May 2022
Cited by 12 | Viewed by 7755
Abstract
It is now more than 100 years since the coconut rhinoceros beetle (CRB: Oryctes rhinoceros L.) was first detected in the Pacific Island state of Samoa. The exotic pest from Asia became the principal pest of coconut palms in Samoa and, from this [...] Read more.
It is now more than 100 years since the coconut rhinoceros beetle (CRB: Oryctes rhinoceros L.) was first detected in the Pacific Island state of Samoa. The exotic pest from Asia became the principal pest of coconut palms in Samoa and, from this first point of invasion, spread to several surrounding countries in the South-West Pacific Ocean. An intensive control operation was initiated, but the beetle could not be eliminated. Various pest management strategies were attempted but had limited success until the introduction of a biological control agent (BCA), Oryctes rhinoceros nudivirus (OrNV), during the late 1960s and early 1970s. The biocontrol release was very successful and became the prime example of “classical biological control” of an insect pest by a virus. Changing economic and social conditions in Samoa and other islands of the Pacific require a re-evaluation of the threat of CRB to coconut production to suggest how the IPM system may be modified to meet future needs. Therefore, it is timely to review the history of CRB in Samoa and summarize experiences in development of an integrated pest management (IPM) system limiting the impact of the pest. We also present results from a recent study conducted in 2020 on the island of Upolu to define the current status of the CRB population and its BCA, OrNV. The lessons from Samoa, with its long history of containment and management of CRB, are applicable to more recent invasion sites. Recommendations are provided to modify the IPM programme to enhance the sustainable control of CRB and support the ongoing coconut replantation program promoted by the Samoan government. Full article
(This article belongs to the Special Issue Coleoptera as Pest and Biological Agents in Agricultural and Forest Ecosystems)
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32 pages, 4788 KiB  
Review
Protists in the Insect Rearing Industry: Benign Passengers or Potential Risk?
by Edouard Bessette and Bryony Williams
Insects 2022, 13(5), 482; https://doi.org/10.3390/insects13050482 - 21 May 2022
Cited by 8 | Viewed by 5549
Abstract
As the insects for food and feed industry grows, a new understanding of the industrially reared insect microbiome is needed to better comprehend the role that it plays in both maintaining insect health and generating disease. While many microbiome projects focus on bacteria, [...] Read more.
As the insects for food and feed industry grows, a new understanding of the industrially reared insect microbiome is needed to better comprehend the role that it plays in both maintaining insect health and generating disease. While many microbiome projects focus on bacteria, fungi or viruses, protists (including microsporidia) can also make up an important part of these assemblages. Past experiences with intensive invertebrate rearing indicate that these parasites, whilst often benign, can rapidly sweep through populations, causing extensive damage. Here, we review the diversity of microsporidia and protist species that are found in reared insect hosts and describe the current understanding of their host spectra, life cycles and the nature of their interactions with hosts. Major entomopathogenic parasite groups with the potential to infect insects currently being reared for food and feed include the Amoebozoa, Apicomplexa, Ciliates, Chlorophyta, Euglenozoa, Ichtyosporea and Microsporidia. However, key gaps exist in the understanding of how many of these entomopathogens affect host biology. In addition, for many of them, there are very limited or even no molecular data, preventing the implementation of molecular detection methods. There is now a pressing need to develop and use novel molecular tools, coupled with standard molecular diagnostic methods, to help unlock their biology and predict the effects of these poorly studied protist parasites in intensive insect rearing systems. Full article
(This article belongs to the Special Issue Insect–Pathogen Interactions in Mass-Reared Insects)
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20 pages, 1917 KiB  
Review
Olfactory Strategies in the Defensive Behaviour of Insects
by Kavitha Kannan, C. Giovanni Galizia and Morgane Nouvian
Insects 2022, 13(5), 470; https://doi.org/10.3390/insects13050470 - 18 May 2022
Cited by 27 | Viewed by 9179
Abstract
Most animals must defend themselves in order to survive. Defensive behaviour includes detecting predators or intruders, avoiding them by staying low-key or escaping or deterring them away by means of aggressive behaviour, i.e., attacking them. Responses vary across insect species, ranging from individual [...] Read more.
Most animals must defend themselves in order to survive. Defensive behaviour includes detecting predators or intruders, avoiding them by staying low-key or escaping or deterring them away by means of aggressive behaviour, i.e., attacking them. Responses vary across insect species, ranging from individual responses to coordinated group attacks in group-living species. Among different modalities of sensory perception, insects predominantly use the sense of smell to detect predators, intruders, and other threats. Furthermore, social insects, such as honeybees and ants, communicate about danger by means of alarm pheromones. In this review, we focus on how olfaction is put to use by insects in defensive behaviour. We review the knowledge of how chemical signals such as the alarm pheromone are processed in the insect brain. We further discuss future studies for understanding defensive behaviour and the role of olfaction. Full article
(This article belongs to the Special Issue Recent Advances in Physiology of Insect Olfaction)
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26 pages, 7619 KiB  
Article
Insects in Art during an Age of Environmental Turmoil
by Barrett Anthony Klein and Tierney Brosius
Insects 2022, 13(5), 448; https://doi.org/10.3390/insects13050448 - 9 May 2022
Cited by 6 | Viewed by 10460
Abstract
Humans are reshaping the planet in impressive, and impressively self-destructive, ways. Evidence and awareness of our environmental impact has failed to elicit meaningful change in reversing our behavior. A multifaceted approach to communicating human-induced environmental destruction is critical, and art can affect our [...] Read more.
Humans are reshaping the planet in impressive, and impressively self-destructive, ways. Evidence and awareness of our environmental impact has failed to elicit meaningful change in reversing our behavior. A multifaceted approach to communicating human-induced environmental destruction is critical, and art can affect our behavior by its power to evoke emotions. Artists often use insects in their works because of our intimate and varied relationship with this diverse, abundant lineage of animals. We surveyed work by 73 artists featuring insects or insect bodily products to gauge how extensively artists are addressing anthropogenic environmental distress, and what insects they are choosing as subjects in the process. Categories often cited as contributing to species extinction are (1) habitat destruction, (2) invasive species, (3) pollution, (4) human population, and (5) overharvesting. After adding insect-specific categories of (6) decline of insect pollinators and (7) the intentional modification or extermination of insects, we categorized our surveyed works, confirming categorizations with 53 of the living artists. Forty-seven percent of the artists addressed habitat destruction or climate change, but some other categories were severely underrepresented, with almost no work explicitly addressing overpopulation or overharvesting. Artists favored Hymenoptera (62%) over potentially more species-rich orders. Recognizing these biases could alert scientists, artists, and others to more effectively communicate messages of universal importance. Full article
(This article belongs to the Collection Cultural Entomology: Our Love-hate Relationship with Insects)
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19 pages, 1080 KiB  
Review
Edible Insect Farming in the Context of the EU Regulations and Marketing—An Overview
by Krystyna Żuk-Gołaszewska, Remigiusz Gałęcki, Kazimierz Obremski, Sergiy Smetana, Szczepan Figiel and Janusz Gołaszewski
Insects 2022, 13(5), 446; https://doi.org/10.3390/insects13050446 - 7 May 2022
Cited by 76 | Viewed by 13370
Abstract
Insects are increasingly being considered as an attractive source of protein that can cater to the growing demand for food around the world and promote the development of sustainable food systems. Commercial insect farms have been established in various countries, mainly in Asia, [...] Read more.
Insects are increasingly being considered as an attractive source of protein that can cater to the growing demand for food around the world and promote the development of sustainable food systems. Commercial insect farms have been established in various countries, mainly in Asia, but in Europe, edible insects have not yet emerged as a viable alternative to traditional plant- and animal-based sources of protein. In this paper, we present an interdisciplinary overview of the technological aspects of edible insect farming in the context of the EU regulations and marketing. Based on a review of the literature, we have concluded that edible insect farming can be a viable business sector that significantly contributes to the overall sustainability of food systems if the appropriate regulations are introduced and food safety standards are guaranteed. However, the success of the edible insect industry also requires consumer acceptance of entomophagy, which is rather low in Western societies. Therefore, targeted marketing strategies are indispensable to support the implementation of edible insect programs. Full article
(This article belongs to the Collection Edible Insects and Circular Economy)
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28 pages, 716 KiB  
Guidelines
Strain Characterisation for Measuring Bioefficacy of ITNs Treated with Two Active Ingredients (Dual-AI ITNs): Developing a Robust Protocol by Building Consensus
by Rosemary S. Lees, Jennifer S. Armistead, Salum Azizi, Edi Constant, Christen Fornadel, John E. Gimnig, Janet Hemingway, Daniel Impoinvil, Seth R. Irish, William Kisinza, Natalie Lissenden, Henry D. Mawejje, Louisa A. Messenger, Sarah Moore, Corine Ngufor, Richard Oxborough, Natacha Protopopoff, Hilary Ranson, Graham Small, Joseph Wagman, David Weetman, Sarah Zohdy and Angus Spiersadd Show full author list remove Hide full author list
Insects 2022, 13(5), 434; https://doi.org/10.3390/insects13050434 - 6 May 2022
Cited by 13 | Viewed by 4600
Abstract
Durability monitoring of insecticide-treated nets (ITNs) containing a pyrethroid in combination with a second active ingredient (AI) must be adapted so that the insecticidal bioefficacy of each AI can be monitored independently. An effective way to do this is to measure rapid knock [...] Read more.
Durability monitoring of insecticide-treated nets (ITNs) containing a pyrethroid in combination with a second active ingredient (AI) must be adapted so that the insecticidal bioefficacy of each AI can be monitored independently. An effective way to do this is to measure rapid knock down of a pyrethroid-susceptible strain of mosquitoes to assess the bioefficacy of the pyrethroid component and to use a pyrethroid-resistant strain to measure the bioefficacy of the second ingredient. To allow robust comparison of results across tests within and between test facilities, and over time, protocols for bioefficacy testing must include either characterisation of the resistant strain, standardisation of the mosquitoes used for bioassays, or a combination of the two. Through a series of virtual meetings, key stakeholders and practitioners explored different approaches to achieving these goals. Via an iterative process we decided on the preferred approach and produced a protocol consisting of characterising mosquitoes used for bioefficacy testing before and after a round of bioassays, for example at each time point in a durability monitoring study. We present the final protocol and justify our approach to establishing a standard methodology for durability monitoring of ITNs containing pyrethroid and a second AI. Full article
(This article belongs to the Special Issue Insecticides for Mosquito Control: Strengthening the Evidence Base)
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31 pages, 764 KiB  
Article
Genotype-by-Diet Interactions for Larval Performance and Body Composition Traits in the Black Soldier Fly, Hermetia illucens
by Christoph Sandrock, Simon Leupi, Jens Wohlfahrt, Cengiz Kaya, Maike Heuel, Melissa Terranova, Wolf U. Blanckenhorn, Wilhelm Windisch, Michael Kreuzer and Florian Leiber
Insects 2022, 13(5), 424; https://doi.org/10.3390/insects13050424 - 30 Apr 2022
Cited by 25 | Viewed by 4737
Abstract
Further advancing black soldier fly (BSF) farming for waste valorisation and more sustainable global protein supplies critically depends on targeted exploitation of genotype-phenotype associations in this insect, comparable to conventional livestock. This study used a fully crossed factorial design of rearing larvae of [...] Read more.
Further advancing black soldier fly (BSF) farming for waste valorisation and more sustainable global protein supplies critically depends on targeted exploitation of genotype-phenotype associations in this insect, comparable to conventional livestock. This study used a fully crossed factorial design of rearing larvae of four genetically distinct BSF strains (FST: 0.11–0.35) on three nutritionally different diets (poultry feed, food waste, poultry manure) to investigate genotype-by-environment interactions. Phenotypic responses included larval growth dynamics over time, weight at harvest, mortality, biomass production with respective contents of ash, fat, and protein, including amino acid profiles, as well as bioconversion and nitrogen efficiency, reduction of dry matter and relevant fibre fractions, and dry matter loss (emissions). Virtually all larval performance and body composition traits were substantially influenced by diet but also characterised by ample BSF genetic variation and, most importantly, by pronounced interaction effects between the two. Across evaluated phenotypes, variable diet-dependent rankings and the lack of generally superior BSF strains indicate the involvement of trade-offs between traits, as their relationships may even change signs. Conflicting resource allocation in light of overall BSF fitness suggests anticipated breeding programs will require complex and differential selection strategies to account for pinpointed trait maximisation versus multi-purpose resilience. Full article
(This article belongs to the Section Role of Insects in Human Society)
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15 pages, 6265 KiB  
Article
Reactive Oxygen Species Initiate Defence Responses of Potato Photosystem II to Sap-Sucking Insect Feeding
by Ilektra Sperdouli, Stefanos S. Andreadis, Ioannis-Dimosthenis S. Adamakis, Julietta Moustaka, Eleni I. Koutsogeorgiou and Michael Moustakas
Insects 2022, 13(5), 409; https://doi.org/10.3390/insects13050409 - 24 Apr 2022
Cited by 22 | Viewed by 3932
Abstract
Potato, Solanum tuberosum L., one of the most commonly cultivated horticultural crops throughout the world, is susceptible to a variety of herbivory insects. In the present study, we evaluated the consequence of feeding by the sap-sucking insect Halyomorpha halys on potato leaf photosynthetic [...] Read more.
Potato, Solanum tuberosum L., one of the most commonly cultivated horticultural crops throughout the world, is susceptible to a variety of herbivory insects. In the present study, we evaluated the consequence of feeding by the sap-sucking insect Halyomorpha halys on potato leaf photosynthetic efficiency. By using chlorophyll fluorescence imaging methodology, we examined photosystem II (PSII) photochemistry in terms of feeding and at the whole leaf area. The role of reactive oxygen species (ROS) in potato’s defence response mechanism immediately after feeding was also assessed. Even 3 min after feeding, increased ROS generation was observed to diffuse through the leaf central vein, probably to act as a long-distance signalling molecule. The proportion of absorbed energy being used in photochemistry (ΦPSII) at the whole leaf level, after 20 min of feeding, was reduced by 8% compared to before feeding due to the decreased number of open PSII reaction centres (qp). After 90 min of feeding, ΦPSII decreased by 46% at the whole leaf level. Meanwhile, at the feeding zones, which were located mainly in the proximity of the leaf midrib, ΦPSII was lower than 85%, with a concurrent increase in singlet-excited oxygen (1O2) generation, which is considered to be harmful. However, the photoprotective mechanism (ΦNPQ), which was highly induced 90 min after feeding, was efficient to compensate for the decrease in the quantum yield of PSII photochemistry (ΦPSII). Therefore, the quantum yield of non-regulated energy loss in PSII (ΦNO), which represents 1O2 generation, remained unaffected at the whole leaf level. We suggest that the potato PSII response to sap-sucking insect feeding underlies the ROS-dependent signalling that occurs immediately and initiates a photoprotective PSII defence response to reduce herbivory damage. A controlled ROS burst can be considered the primary plant defence response mechanism to herbivores. Full article
(This article belongs to the Collection Plant Responses to Insect Herbivores)
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18 pages, 2469 KiB  
Article
The Early Season Community of Flower-Visiting Arthropods in a High-Altitude Alpine Environment
by Marco Bonelli, Elena Eustacchio, Daniele Avesani, Verner Michelsen, Mattia Falaschi, Marco Caccianiga, Mauro Gobbi and Morena Casartelli
Insects 2022, 13(4), 393; https://doi.org/10.3390/insects13040393 - 16 Apr 2022
Cited by 8 | Viewed by 4694
Abstract
In mountain ecosystems, climate change can cause spatiotemporal shifts, impacting the composition of communities and altering fundamental biotic interactions, such as those involving flower-visiting arthropods. On of the main problems in assessing the effects of climate change on arthropods in these environments is [...] Read more.
In mountain ecosystems, climate change can cause spatiotemporal shifts, impacting the composition of communities and altering fundamental biotic interactions, such as those involving flower-visiting arthropods. On of the main problems in assessing the effects of climate change on arthropods in these environments is the lack of baseline data. In particular, the arthropod communities on early flowering high-altitude plants are poorly investigated, although the early season is a critical moment for possible mismatches. In this study, we characterised the flower-visiting arthropod community on the early flowering high-altitude Alpine plant, Androsace brevis (Primulaceae). In addition, we tested the effect of abiotic factors (temperature and wind speed) and other variables (time, i.e., hour of the day, and number of flowers per plant) on the occurrence, abundance, and diversity of this community. A. brevis is a vulnerable endemic species growing in the Central Alps above 2000 m asl and flowering for a very short period immediately after snowmelt, thus representing a possible focal plant for arthropods in this particular moment of the season. Diptera and Hymenoptera were the main flower visitors, and three major features of the community emerged: an evident predominance of anthomyiid flies among Diptera, a rare presence of bees, and a relevant share of parasitoid wasps. Temperature and time (hour of the day), but not wind speed and number of flowers per plant, affected the flower visitors’ activity. Our study contributes to (1) defining the composition of high-altitude Alpine flower-visiting arthropod communities in the early season, (2) establishing how these communities are affected by environmental variables, and (3) setting the stage for future evaluation of climate change effects on flower-visiting arthropods in high-altitude environments in the early season. Full article
(This article belongs to the Collection Insects in Mountain Ecosystems)
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18 pages, 1225 KiB  
Review
Bugs in Bugs: The Role of Probiotics and Prebiotics in Maintenance of Health in Mass-Reared Insects
by Carlotta Savio, Loretta Mugo-Kamiri and Jennifer K. Upfold
Insects 2022, 13(4), 376; https://doi.org/10.3390/insects13040376 - 11 Apr 2022
Cited by 31 | Viewed by 6301
Abstract
Interactions between insects and their microbiota affect insect behaviour and evolution. When specific microorganisms are provided as a dietary supplement, insect reproduction, food conversion and growth are enhanced and health is improved in cases of nutritional deficiency or pathogen infection. The purpose of [...] Read more.
Interactions between insects and their microbiota affect insect behaviour and evolution. When specific microorganisms are provided as a dietary supplement, insect reproduction, food conversion and growth are enhanced and health is improved in cases of nutritional deficiency or pathogen infection. The purpose of this review is to provide an overview of insect–microbiota interactions, to review the role of probiotics, their general use in insects reared for food and feed, and their interactions with the host microbiota. We review how bacterial strains have been selected for insect species reared for food and feed and discuss methods used to isolate and measure the effectiveness of a probiotic. We outline future perspectives on probiotic applications in mass-reared insects. Full article
(This article belongs to the Special Issue Insect–Pathogen Interactions in Mass-Reared Insects)
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20 pages, 17002 KiB  
Review
Enantiomeric Discrimination in Insects: The Role of OBPs and ORs
by Cassie Sims, Michael A. Birkett and David M. Withall
Insects 2022, 13(4), 368; https://doi.org/10.3390/insects13040368 - 8 Apr 2022
Cited by 19 | Viewed by 4548
Abstract
Olfaction is a complex recognition process that is critical for chemical communication in insects. Though some insect species are capable of discrimination between compounds that are structurally similar, little is understood about how this high level of discrimination arises. Some insects rely on [...] Read more.
Olfaction is a complex recognition process that is critical for chemical communication in insects. Though some insect species are capable of discrimination between compounds that are structurally similar, little is understood about how this high level of discrimination arises. Some insects rely on discriminating between enantiomers of a compound, demonstrating an ability for highly selective recognition. The role of two major peripheral olfactory proteins in insect olfaction, i.e., odorant-binding proteins (OBPs) and odorant receptors (ORs) has been extensively studied. OBPs and ORs have variable discrimination capabilities, with some found to display highly specialized binding capability, whilst others exhibit promiscuous binding activity. A deeper understanding of how odorant-protein interactions induce a response in an insect relies on further analysis such as structural studies. In this review, we explore the potential role of OBPs and ORs in highly specific recognition, specifically enantiomeric discrimination. We summarize the state of research into OBP and OR function and focus on reported examples in the literature of clear enantiomeric discrimination by these proteins. Full article
(This article belongs to the Special Issue Recent Advances in Physiology of Insect Olfaction)
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28 pages, 18075 KiB  
Review
The Symbiotic Fungus Leucoagaricus gongylophorus (Möller) Singer (Agaricales, Agaricaceae) as a Target Organism to Control Leaf-Cutting Ants
by Sean Araújo, Janaína Seibert, Ana Ruani, Ricardo Alcántara-de la Cruz, Artur Cruz, Alana Pereira, Doraí Zandonai, Moacir Forim, Maria Fátima Silva, Odair Bueno and João Fernandes
Insects 2022, 13(4), 359; https://doi.org/10.3390/insects13040359 - 6 Apr 2022
Cited by 4 | Viewed by 5831
Abstract
Atta and Acromyrmex are the main genera of leaf-cutting ants present in North and South America, causing extensive damage to agroforestry. Control of the ants requires high handling costs with few effective methods available to decrease the losses. The symbiosis between the leaf-cutting [...] Read more.
Atta and Acromyrmex are the main genera of leaf-cutting ants present in North and South America, causing extensive damage to agroforestry. Control of the ants requires high handling costs with few effective methods available to decrease the losses. The symbiosis between the leaf-cutting ants and the fungus Leucoagaricus gongylophorus is essential for ant nest survival. Therefore, L. gongylophorus may be a key target in controlling leaf-cutting ants, since its reduction may cause an imbalance in the symbiosis necessary to maintain the nest. Among the options for natural fungal control, plant species are considered important sources of compounds belonging to several classes of natural products that show potential as antifungal agents. This review also presents studies that establish that the antagonist fungi from the Escovopsis and Trichoderma genera effectively reduce the development of L. gongylophorus. The development of nanostructured delivery systems, which have shown advantages over conventional formulations, is suggested for ant control; no commercial nanotechnology-based product has yet been developed, and this appears to be a new approach for future studies. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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21 pages, 620 KiB  
Review
Multimodal Information Processing and Associative Learning in the Insect Brain
by Devasena Thiagarajan and Silke Sachse
Insects 2022, 13(4), 332; https://doi.org/10.3390/insects13040332 - 28 Mar 2022
Cited by 21 | Viewed by 7313
Abstract
The study of sensory systems in insects has a long-spanning history of almost an entire century. Olfaction, vision, and gustation are thoroughly researched in several robust insect models and new discoveries are made every day on the more elusive thermo- and mechano-sensory systems. [...] Read more.
The study of sensory systems in insects has a long-spanning history of almost an entire century. Olfaction, vision, and gustation are thoroughly researched in several robust insect models and new discoveries are made every day on the more elusive thermo- and mechano-sensory systems. Few specialized senses such as hygro- and magneto-reception are also identified in some insects. In light of recent advancements in the scientific investigation of insect behavior, it is not only important to study sensory modalities individually, but also as a combination of multimodal inputs. This is of particular significance, as a combinatorial approach to study sensory behaviors mimics the real-time environment of an insect with a wide spectrum of information available to it. As a fascinating field that is recently gaining new insight, multimodal integration in insects serves as a fundamental basis to understand complex insect behaviors including, but not limited to navigation, foraging, learning, and memory. In this review, we have summarized various studies that investigated sensory integration across modalities, with emphasis on three insect models (honeybees, ants and flies), their behaviors, and the corresponding neuronal underpinnings. Full article
(This article belongs to the Special Issue Recent Advances in Physiology of Insect Olfaction)
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18 pages, 2731 KiB  
Article
Field Suppression of Spotted Wing Drosophila (SWD) (Drosophila suzukii Matsumura) Using the Sterile Insect Technique (SIT)
by Rafael A. Homem, Zeus Mateos-Fierro, Rory Jones, Daniel Gilbert, Andrew R. Mckemey, Glen Slade and Michelle T. Fountain
Insects 2022, 13(4), 328; https://doi.org/10.3390/insects13040328 - 26 Mar 2022
Cited by 13 | Viewed by 5627
Abstract
Drosophila suzukii (spotted wing drosophila—SWD) is an economically important pest of soft and stone fruit worldwide. Control relies on broad-spectrum insecticides, which are neither fully effective nor environmentally sustainable. The sterile insect technique (SIT) is a proven, effective and environmentally friendly pest-management tool. [...] Read more.
Drosophila suzukii (spotted wing drosophila—SWD) is an economically important pest of soft and stone fruit worldwide. Control relies on broad-spectrum insecticides, which are neither fully effective nor environmentally sustainable. The sterile insect technique (SIT) is a proven, effective and environmentally friendly pest-management tool. Here, we investigated, for the first time, the potential of using SIT to control D. suzukii in field conditions without physical barriers that limit insect invasion. A proprietary method of rearing and irradiation with X-rays was used to obtain males that were > 99% sterile. Sterile males were released twice per week from April to October 2021 on a site in Kent, UK, where everbearing strawberries were grown in open polytunnels. The infestation of wild female D. suzukii was monitored weekly using red sticky traps with dry lure at the treated site and at two similar control sites that did not receive sterile male releases. Releases of sterile males suppressed the wild female D. suzukii population by up to 91% in comparison with the control sites. We thus demonstrated the feasibility of SIT to achieve season-long control of D. suzukii using early, sustained and dynamically targeted releases of sterile males. This provides a promising environmentally friendly method to control this important pest. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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8 pages, 946 KiB  
Article
Effect of Temperature and Photoperiod on Development, Survival, and Growth Rate of Mealworms, Tenebrio molitor
by Stephan Eberle, Lisa-Marie Schaden, Johannes Tintner, Christian Stauffer and Martin Schebeck
Insects 2022, 13(4), 321; https://doi.org/10.3390/insects13040321 - 24 Mar 2022
Cited by 33 | Viewed by 9946
Abstract
Insects are a potential substitute for conventional meat and can be part of a sustainable human diet due to their valuable nutrients and relatively low environmental production impact. One species that is already produced for human consumption and livestock feed is the mealworm, [...] Read more.
Insects are a potential substitute for conventional meat and can be part of a sustainable human diet due to their valuable nutrients and relatively low environmental production impact. One species that is already produced for human consumption and livestock feed is the mealworm, i.e., larvae of Tenebrio molitor. Knowledge of the effects of temperature, and particularly photoperiod, on mealworm development is scarce, but crucial for the improvement of rearing. Therefore, the effects of three temperatures (20 °C, 25 °C, and 30 °C), in combination with three photoperiods (long-day—16 h:8 h light:dark; short-day—8 h:16 h light:dark, and constant darkness) on mealworm survival, developmental time, and growth rate were tested. We describe a significant effect of temperature on survival rate, developmental time, and growth rate. Furthermore, significant effects of photoperiod on developmental time and growth rate were found. At 25 and 30 °C and constant darkness, the highest survival and growth rate, along with the shortest developmental time, were observed. Our data can be used to improve the mass rearing of mealworms for an efficient production of food and feed. Full article
(This article belongs to the Section Other Arthropods and General Topics)
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14 pages, 3472 KiB  
Article
A Practical Insecticide Resistance Monitoring Bioassay for Orally Ingested Dinotefuran in Anopheles Malaria Vectors
by George John Ian Parsons, Rosemary Susan Lees, Sofia Balaska and John Vontas
Insects 2022, 13(4), 311; https://doi.org/10.3390/insects13040311 - 22 Mar 2022
Cited by 6 | Viewed by 3920
Abstract
Attractive Toxic Sugar Baits (ATSB) deployed outdoors are likely to be particularly effective against outdoor biting mosquitoes and, if they contain insecticides with a different mode of action, mosquitoes resistant to pyrethroids. One such ATSB based on the neonicotinoid dinotefuran is currently under [...] Read more.
Attractive Toxic Sugar Baits (ATSB) deployed outdoors are likely to be particularly effective against outdoor biting mosquitoes and, if they contain insecticides with a different mode of action, mosquitoes resistant to pyrethroids. One such ATSB based on the neonicotinoid dinotefuran is currently under evaluation in Africa. As with any insecticide-based intervention, it will be important to monitor for the possible emergence of vector resistance. While methods for detecting resistance to insecticides via tarsal contact are recommended by the World Health Organization (WHO), these may not be applicable for orally ingested insecticides. Here, a new ingestion assay, appropriate for a controlled laboratory setting, is described using fluorescein sodium salt (uranine) as a feeding marker. Conventional topical application bioassays, more appropriate for routine deployment, have also been used to apply dinotefuran to the thorax of adult Anopheles mosquitoes with an organic carrier to bypass lipid cuticle barriers. The two methods were compared by establishing lethal doses (LD) in several Anopheles strains. The similarity of the ratios of susceptibility to dinotefuran between pairs of pyrethroid susceptible and resistant strains validates topical application as a suitable, more practical and field applicable method for monitoring for the emergence of resistance to orally ingested dinotefuran. A discriminating dose is proposed, which will be further validated against field populations and used to routinely monitor for the emergence of resistance alongside ATSB trials. Full article
(This article belongs to the Special Issue Insecticides for Mosquito Control: Strengthening the Evidence Base)
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14 pages, 1766 KiB  
Article
Larvicidal Activity of Carbon Black against the Yellow Fever Mosquito Aedes aegypti
by Erick J. Martínez Rodríguez, Parker Evans, Megha Kalsi, Noah Rosenblatt, Morgan Stanley and Peter M. Piermarini
Insects 2022, 13(3), 307; https://doi.org/10.3390/insects13030307 - 20 Mar 2022
Cited by 11 | Viewed by 6404
Abstract
The yellow fever mosquito Aedes aegypti is one of the deadliest animals on the planet because it transmits several medically important arboviruses, including Zika, chikungunya, dengue, and yellow fever. Carbon-based nanoparticles (CNPs) derived from natural sources have previously been shown to have toxic [...] Read more.
The yellow fever mosquito Aedes aegypti is one of the deadliest animals on the planet because it transmits several medically important arboviruses, including Zika, chikungunya, dengue, and yellow fever. Carbon-based nanoparticles (CNPs) derived from natural sources have previously been shown to have toxic effects on mosquito larvae and offer a potential alternative to chemical insecticides such as pyrethroids, for which mosquitoes have evolved resistance. However, CNPs derived from industrial sources, such as carbon black, have not previously been evaluated as larvicides. Here, we evaluate the effects of a commercially-available carbon black, EMPEROR® 1800 (E1800), on mortality and development of pyrethroid-susceptible (PS) and pyrethroid-resistant (PR) strains of Ae. aegypti. We found that E1800 exhibited concentration-dependent mortality against 1st instar larvae of both strains within the first 120 h after exposure, but after this period, surviving larvae did not show delays in their development to adults. Physical characterization of E1800 suspensions suggests that they form primary particles of ~30 nm in diameter that fuse into fundamental aggregates of ~170 nm in diameter. Notably, larvae treated with E1800 showed internal accumulation of E1800 in the gut and external accumulation on the respiratory siphon, anal papillae, and setae, suggesting a physical mode of toxic action. Taken together, our results suggest that E1800 has potential use as a larvicide with a novel mode of action for controlling PS and PR mosquitoes. Full article
(This article belongs to the Special Issue Integrated Management of Public Health Pests)
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43 pages, 731 KiB  
Review
Integrative Alternative Tactics for Ixodid Control
by Allan T. Showler and Perot Saelao
Insects 2022, 13(3), 302; https://doi.org/10.3390/insects13030302 - 18 Mar 2022
Cited by 17 | Viewed by 5023
Abstract
Ixodids (hard ticks), ectoparasitic arthropods that vector the causal agents of many serious diseases of humans, domestic animals, and wildlife, have become increasingly difficult to control because of the development of resistance against commonly applied synthetic chemical-based acaricides. Resistance has prompted searches for [...] Read more.
Ixodids (hard ticks), ectoparasitic arthropods that vector the causal agents of many serious diseases of humans, domestic animals, and wildlife, have become increasingly difficult to control because of the development of resistance against commonly applied synthetic chemical-based acaricides. Resistance has prompted searches for alternative, nonconventional control tactics that can be used as part of integrated ixodid management strategies and for mitigating resistance to conventional acaricides. The quest for alternative control tactics has involved research on various techniques, each influenced by many factors, that have achieved different degrees of success. Alternative approaches include cultural practices, ingested and injected medications, biological control, animal- and plant-based substances, growth regulators, and inert desiccant dusts. Research on biological control of ixodids has mainly focused on predators, parasitoid wasps, infective nematodes, and pathogenic bacteria and fungi. Studies on animal-based substances have been relatively limited, but research on botanicals has been extensive, including whole plant, extract, and essential oil effects on ixodid mortality, behavior, and reproduction. The inert dusts kaolin, silica gel, perlite, and diatomaceous earth are lethal to ixodids, and they are impervious to environmental degradation, unlike chemical-based toxins, remaining effective until physically removed. Full article
(This article belongs to the Special Issue Integrated Management of Public Health Pests)
37 pages, 5267 KiB  
Review
Impacts of Wildflower Interventions on Beneficial Insects in Fruit Crops: A Review
by Michelle T. Fountain
Insects 2022, 13(3), 304; https://doi.org/10.3390/insects13030304 - 18 Mar 2022
Cited by 39 | Viewed by 8489
Abstract
Integrated pest management (IPM) has been practiced by the fruit industry for at least 30 years. Naturally occurring beneficial insects have been encouraged to thrive alongside introduced predatory insects. However, Conservation Biological Control (CBC) and augmented biocontrol through the release of large numbers [...] Read more.
Integrated pest management (IPM) has been practiced by the fruit industry for at least 30 years. Naturally occurring beneficial insects have been encouraged to thrive alongside introduced predatory insects. However, Conservation Biological Control (CBC) and augmented biocontrol through the release of large numbers of natural enemies is normally only widely adopted when a pest has become resistant to available conventional pesticides and control has begun to break down. In addition, the incorporation of wild pollinator management, essential to fruit production, has, in the past, not been a priority but is now increasingly recognized through integrated pest and pollinator management (IPPM). This review focuses on the impacts on pest regulation and pollination services in fruit crops through the delivery of natural enemies and pollinating insects by provisioning areas of fruiting crops with floral resources. Most of the studies in this review highlighted beneficial or benign impacts of floral resource prevision to fruit crops. However, placement in the landscape and spill-over of beneficial arthropods into the crop can be influential and limiting. This review also highlights the need for longer-term ecological studies to understand the impacts of changing arthropod communities over time and the opportunity to tailor wildflower mixes to specific crops for increased pest control and pollination benefits, ultimately impacting fruit growers bottom-line with less reliance on pesticides. Full article
(This article belongs to the Special Issue Pollinator Diversity in Sustainable Agroecosystems)
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25 pages, 1978 KiB  
Review
The Contribution of Silk Fibroin in Biomedical Engineering
by Cristian Lujerdean, Gabriela-Maria Baci, Alexandra-Antonia Cucu and Daniel Severus Dezmirean
Insects 2022, 13(3), 286; https://doi.org/10.3390/insects13030286 - 14 Mar 2022
Cited by 97 | Viewed by 10622
Abstract
Silk fibroin (SF) is a natural protein (biopolymer) extracted from the cocoons of Bombyx mori L. (silkworm). It has many properties of interest in the field of biotechnology, the most important being biodegradability, biocompatibility and robust mechanical strength with high tensile strength. SF [...] Read more.
Silk fibroin (SF) is a natural protein (biopolymer) extracted from the cocoons of Bombyx mori L. (silkworm). It has many properties of interest in the field of biotechnology, the most important being biodegradability, biocompatibility and robust mechanical strength with high tensile strength. SF is usually dissolved in water-based solvents and can be easily reconstructed into a variety of material formats, including films, mats, hydrogels, and sponges, by various fabrication techniques (spin coating, electrospinning, freeze-drying, and physical or chemical crosslinking). Furthermore, SF is a feasible material used in many biomedical applications, including tissue engineering (3D scaffolds, wounds dressing), cancer therapy (mimicking the tumor microenvironment), controlled drug delivery (SF-based complexes), and bone, eye and skin regeneration. In this review, we describe the structure, composition, general properties, and structure–properties relationship of SF. In addition, the main methods used for ecological extraction and processing of SF that make it a green material are discussed. Lastly, technological advances in the use of SF-based materials are addressed, especially in healthcare applications such as tissue engineering and cancer therapeutics. Full article
(This article belongs to the Special Issue Silkworm and Silk: Traditional and Innovative Applications)
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15 pages, 331 KiB  
Review
A Review of Commercial Metarhizium- and Beauveria-Based Biopesticides for the Biological Control of Ticks in the USA
by Cheryl Frank Sullivan, Bruce L. Parker and Margaret Skinner
Insects 2022, 13(3), 260; https://doi.org/10.3390/insects13030260 - 5 Mar 2022
Cited by 43 | Viewed by 7145
Abstract
There is a need for the development of sustainable, nonchemical tick management strategies. Mycoacaricide and mycoinsecticide product development worldwide has focused primarily on fungi in the genera Beauveria (Hypocreales: Cordycipitaceae) and Metarhizium (Hypocreales: Clavicipitaceae). Microbial biopesticides containing entomopathogenic fungi have potential in tick [...] Read more.
There is a need for the development of sustainable, nonchemical tick management strategies. Mycoacaricide and mycoinsecticide product development worldwide has focused primarily on fungi in the genera Beauveria (Hypocreales: Cordycipitaceae) and Metarhizium (Hypocreales: Clavicipitaceae). Microbial biopesticides containing entomopathogenic fungi have potential in tick management. However, despite considerable progress in the development of fungal biopesticides over the past 20 years, the establishment of commercial products available for use against ticks continues to be slow. We reviewed published scientific literature and compiled a comprehensive list of reports of the effectiveness of commercial biopesticides based on the fungal genera Metarhizium and Beauveria and registered for use in the USA against ixodid ticks under laboratory and field conditions. We also report on results when these biopesticides were used as a part of integrated tick management. Until efficacious fungus-based products become more available, tick management will rely primarily on synthetic chemical acaricides, with natural-product acaricides as the alternative. Full article
(This article belongs to the Special Issue Ecology of Ticks and Their Control)
19 pages, 1110 KiB  
Article
Interactions between Rice Resistance to Planthoppers and Honeydew-Related Egg Parasitism under Varying Levels of Nitrogenous Fertilizer
by Ainara Peñalver-Cruz and Finbarr G. Horgan
Insects 2022, 13(3), 251; https://doi.org/10.3390/insects13030251 - 1 Mar 2022
Cited by 6 | Viewed by 4695
Abstract
Host plant resistance is the most researched method for the management of planthoppers and leafhoppers in tropical rice. For optimal effects, resistance should be resilient to fertilizer inputs and work in synergy with natural enemies. In field plot experiments, we examined how rice [...] Read more.
Host plant resistance is the most researched method for the management of planthoppers and leafhoppers in tropical rice. For optimal effects, resistance should be resilient to fertilizer inputs and work in synergy with natural enemies. In field plot experiments, we examined how rice resistance and fertilizer inputs affect mortality of planthopper and leafhopper eggs by hymenopteran parasitoids. We used IR62 as a variety with resistance to Nilaparvata lugens (Stål) [BPH], Sogatella furcifera (Horváth) [WBPH] and Nephotettix virescens (Distant) [GLH], and IR64 as a susceptible control. The herbivores were more abundant during wet season sampling in low-nitrogen plots. During this study, parasitoids killed between 31 and 38% of BPH eggs and 24 and 52% of WBPH eggs during four days of field exposure. Parasitism, mainly due to Oligosita spp., was generally higher in high-nitrogen and IR64 plots. Similar densities of eggs in exposed plants suggest that these trends were mediated by semiochemicals and therefore support the Optimal Defense Hypothesis. Honeydew from BPH on IR62 had more xylem-derived wastes than honeydew on IR64. We applied honeydew from both varieties to sentinel plants. Parasitism by Anagrus spp. was higher on plants of either variety treated with honeydew derived from IR62; however, the effect was only apparent in high-nitrogen plots. Results suggest that Anagrus spp., by responding to honeydew, will counter the nitrogen-induced enhancement of planthopper fitness on resistant rice. Full article
(This article belongs to the Collection Biology and Management of Sap-Sucking Pests)
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25 pages, 2985 KiB  
Review
Visible beyond Violet: How Butterflies Manage Ultraviolet
by David Stella and Karel Kleisner
Insects 2022, 13(3), 242; https://doi.org/10.3390/insects13030242 - 28 Feb 2022
Cited by 9 | Viewed by 5625
Abstract
Ultraviolet (UV) means ‘beyond violet’ (from Latin ‘ultra’, meaning ‘beyond’), whereby violet is the colour with the highest frequencies in the ‘visible’ light spectrum. By ‘visible’ we mean human vision, but, in comparison to many other organisms, human visual perception is rather limited [...] Read more.
Ultraviolet (UV) means ‘beyond violet’ (from Latin ‘ultra’, meaning ‘beyond’), whereby violet is the colour with the highest frequencies in the ‘visible’ light spectrum. By ‘visible’ we mean human vision, but, in comparison to many other organisms, human visual perception is rather limited in terms of the wavelengths it can perceive. Still, this is why communication in the UV spectrum is often called hidden, although it most likely plays an important role in communicating various kinds of information among a wide variety of organisms. Since Silberglied’s revolutionary Communication in the Ultraviolet, comprehensive studies on UV signals in a wide list of genera are lacking. This review investigates the significance of UV reflectance (and UV absorption)—a feature often neglected in intra- and interspecific communication studies—mainly in Lepidoptera. Although the text focuses on various butterfly families, links and connections to other animal groups, such as birds, are also discussed in the context of ecology and the evolution of species. The basic mechanisms of UV colouration and factors shaping the characteristics of UV patterns are also discussed in a broad context of lepidopteran communication. Full article
(This article belongs to the Special Issue Reproductive Behaviour in Insects and other Non-Marine Arthropods)
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13 pages, 1778 KiB  
Article
Designing a Pest and Disease Outbreak Warning System for Farmers, Agronomists and Agricultural Input Distributors in East Africa
by Molly E. Brown, Stephen Mugo, Sebastian Petersen and Dominik Klauser
Insects 2022, 13(3), 232; https://doi.org/10.3390/insects13030232 - 26 Feb 2022
Cited by 12 | Viewed by 6007
Abstract
Early warnings of the risks of pest and disease outbreaks are becoming more urgent, with substantial increases in threats to agriculture from invasive pests. With geospatial data improvements in quality and timeliness, models and analytical systems can be used to estimate potential areas [...] Read more.
Early warnings of the risks of pest and disease outbreaks are becoming more urgent, with substantial increases in threats to agriculture from invasive pests. With geospatial data improvements in quality and timeliness, models and analytical systems can be used to estimate potential areas at high risk of yield impacts. The development of decision support systems requires an understanding of what information is needed, when it is needed, and at what resolution and accuracy. Here, we report on a professional review conducted with 53 professional agronomists, retailers, distributors, and growers in East Africa working with the Syngenta Foundation for Sustainable Agriculture. The results showed that respondents reported fall armyworm, stemborers and aphids as being among the most common pests, and that crop diversification was a key strategy to reduce their impact. Chemical and cultural controls were the most common strategies for fall armyworm (FAW) control, and biological control was the least known and least used method. Of the cultural control methods, monitoring and scouting, early planting, and crop rotation with non-host crops were most used. Although pests reduced production, only 55% of respondents were familiar with early warning tools, showing the need for predictive systems that can improve farmer response. Full article
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16 pages, 1535 KiB  
Article
Comparative Screening of Mexican, Rwandan and Commercial Entomopathogenic Nematodes to Be Used against Invasive Fall Armyworm, Spodoptera frugiperda
by Patrick Fallet, Lara De Gianni, Ricardo A. R. Machado, Pamela Bruno, Julio S. Bernal, Patrick Karangwa, Joelle Kajuga, Bancy Waweru, Didace Bazagwira, Thomas Degen, Stefan Toepfer and Ted C. J. Turlings
Insects 2022, 13(2), 205; https://doi.org/10.3390/insects13020205 - 16 Feb 2022
Cited by 27 | Viewed by 4492
Abstract
The fall armyworm (FAW), Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) is an important pest of maize originating from the Americas. It recently invaded Africa and Asia, where it causes severe yield losses to maize. To fight this pest, tremendous quantities of synthetic insecticides are [...] Read more.
The fall armyworm (FAW), Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) is an important pest of maize originating from the Americas. It recently invaded Africa and Asia, where it causes severe yield losses to maize. To fight this pest, tremendous quantities of synthetic insecticides are being used. As a safe and sustainable alternative, we explore the possibility to control FAW with entomopathogenic nematodes (EPN). We tested in the laboratory whether local EPNs, isolated in the invasive range of FAW, are as effective as EPNs from FAW native range or as commercially available EPNs. This work compared the virulence, killing speed and propagation capability of low doses of forty EPN strains, representing twelve species, after placing them with second-, third- and sixth-instar caterpillars as well as pupae. EPN isolated in the invasive range of FAW (Rwanda) were found to be as effective as commercial and EPNs from the native range of FAW (Mexico) at killing FAW caterpillars. In particular, the Rwandan Steinernema carpocapsae strain RW14-G-R3a-2 caused rapid 100% mortality of second- and third-instar and close to 75% of sixth-instar FAW caterpillars. EPN strains and concentrations used in this study were not effective in killing FAW pupae. Virulence varied greatly among EPN strains, underlining the importance of thorough EPN screenings. These findings will facilitate the development of local EPN-based biological control products for sustainable and environmentally friendly control of FAW in East Africa and beyond. Full article
(This article belongs to the Special Issue Entomopathogenic Nematodes: Lethal Parasites of Insects)
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8 pages, 1411 KiB  
Article
The Effect of Resistance to Bt Corn on the Reproductive Output of Spodoptera frugiperda (Lepidoptera: Noctuidae)
by Natália de Souza Ribas, Jeremy N. McNeil, Hernane Dias Araújo, Bruna de Souza Ribas and Eraldo Lima
Insects 2022, 13(2), 196; https://doi.org/10.3390/insects13020196 - 14 Feb 2022
Cited by 5 | Viewed by 3457
Abstract
The fall armyworm (FAW) Spodoptera frugiperda is the most significant lepidopteran corn pest in South American countries. Transgenic Bt corn, producing the Cry1Fa toxins, has been used to control this pest, but there is clear evidence that some FAW populations have developed resistance. [...] Read more.
The fall armyworm (FAW) Spodoptera frugiperda is the most significant lepidopteran corn pest in South American countries. Transgenic Bt corn, producing the Cry1Fa toxins, has been used to control this pest, but there is clear evidence that some FAW populations have developed resistance. To determine if there are costs associated with resistance, we compared the mass of adults, the duration of mating, and the mass of the first spermatophore produced, as well as the lifetime fecundity and fertility of once-mated susceptible (SS) and resistant (RR) females. Adult mass was affected by both sex and strain, with SS females being significantly larger than RR ones, while the inverse was true for males. RR pairs took significantly longer to mate than SS pairs, yet the mass of spermatophores produced by RR males was significantly less than those of SS males. The total number of eggs laid did not differ but the fertility of eggs from once-mated RR pairs was significantly lower than that of SS pairs. Our data provided clear evidence that the development of Bt resistance affected the reproductive capacity of resistant FAW. Full article
(This article belongs to the Special Issue Applied Insect Reproductive Biology)
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14 pages, 825 KiB  
Article
Imported Dengue Case Numbers and Local Climatic Patterns Are Associated with Dengue Virus Transmission in Florida, USA
by Caroline Stephenson, Eric Coker, Samantha Wisely, Song Liang, Rhoel R. Dinglasan and John A. Lednicky
Insects 2022, 13(2), 163; https://doi.org/10.3390/insects13020163 - 3 Feb 2022
Cited by 15 | Viewed by 4995
Abstract
Aedes aegypti mosquitoes are the main vector of dengue viruses globally and are present throughout much of the state of Florida (FL) in the United States of America. However, local transmission of dengue viruses in FL has mainly occurred in the southernmost counties; [...] Read more.
Aedes aegypti mosquitoes are the main vector of dengue viruses globally and are present throughout much of the state of Florida (FL) in the United States of America. However, local transmission of dengue viruses in FL has mainly occurred in the southernmost counties; specifically Monroe and Miami-Dade counties. To get a better understanding of the ecologic risk factors for dengue fever incidence throughout FL, we collected and analyzed numerous environmental factors that have previously been connected to local dengue cases in disease-endemic regions. We analyzed these factors for each county-year in FL, between 2009–2019, using negative binomial regression. Monthly minimum temperature of 17.5–20.8 °C, an average temperature of 26.1–26.7 °C, a maximum temperature of 33.6–34.7 °C, rainfall between 11.4–12.7 cm, and increasing numbers of imported dengue cases were associated with the highest risk of dengue incidence per county-year. To our knowledge, we have developed the first predictive model for dengue fever incidence in FL counties and our findings provide critical information about weather conditions that could increase the risk for dengue outbreaks as well as the important contribution of imported dengue cases to local establishment of the virus in Ae. aegypti populations. Full article
(This article belongs to the Special Issue Vector-Borne Infections: From Ecology to Vector-Microbe-Host Interactions)
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19 pages, 708 KiB  
Review
Improving Natural Enemy Selection in Biological Control through Greater Attention to Chemical Ecology and Host-Associated Differentiation of Target Arthropod Pests
by Morgan N. Thompson, Raul F. Medina, Anjel M. Helms and Julio S. Bernal
Insects 2022, 13(2), 160; https://doi.org/10.3390/insects13020160 - 2 Feb 2022
Cited by 18 | Viewed by 9051
Abstract
Host-associated differentiation (HAD) refers to cases in which genetically distinct populations of a species (e.g., herbivores or natural enemies) preferentially reproduce or feed on different host species. In agroecosystems, HAD often results in unique strains or biotypes of pest species, each attacking different [...] Read more.
Host-associated differentiation (HAD) refers to cases in which genetically distinct populations of a species (e.g., herbivores or natural enemies) preferentially reproduce or feed on different host species. In agroecosystems, HAD often results in unique strains or biotypes of pest species, each attacking different species of crops. However, HAD is not restricted to pest populations, and may cascade to the third trophic level, affecting host selection by natural enemies, and ultimately leading to HAD within natural enemy species. Natural enemy HAD may affect the outcomes of biological control efforts, whether classical, conservation, or augmentative. Here, we explore the potential effects of pest and natural enemy HAD on biological control in agroecosystems, with emphases on current knowledge gaps and implications of HAD for selection of biological control agents. Additionally, given the importance of semiochemicals in mediating interactions between trophic levels, we emphasize the role of chemical ecology in interactions between pests and natural enemies, and suggest areas of consideration for biological control. Overall, we aim to jump-start a conversation concerning the relevance of HAD in biological control by reviewing currently available information on natural enemy HAD, identifying challenges to incorporating HAD considerations into biological control efforts, and proposing future research directions on natural enemy selection and HAD. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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10 pages, 461 KiB  
Article
Could Sterile Aedes albopictus Male Releases Interfere with Aedes aegypti Population in Reunion Island?
by Harilanto Felana Andrianjakarivony, David Damiens, Lucie Marquereau, Benjamin Gaudillat, Nausicaa Habchi-Hanriot and Louis-Clément Gouagna
Insects 2022, 13(2), 146; https://doi.org/10.3390/insects13020146 - 29 Jan 2022
Cited by 2 | Viewed by 2982
Abstract
In Reunion Island, the feasibility of an Aedes albopictus control program using the Sterile Insect Technique (SIT) is studied. Because, in some regions, Ae. albopictus is living in sympatry with Aedes aegypti, the impact of releasing millions of sterile male Ae. albopictus [...] Read more.
In Reunion Island, the feasibility of an Aedes albopictus control program using the Sterile Insect Technique (SIT) is studied. Because, in some regions, Ae. albopictus is living in sympatry with Aedes aegypti, the impact of releasing millions of sterile male Ae. albopictus on female Ae. aegypti reproduction needs to be assessed. Thus, to study the potential heterospecific matings, a marking technique using rhodamine B has been used. Rhodamine is given in solution to male mosquitoes to be incorporated into the male body and seminal fluid and transferred during mating into the bursa inseminalis and spermathecae of females. The presence of rhodamine in females occurred in 15% of cases when Ae. aegypti females were offered non-irradiated Ae. albopictus males, 5% when offered irradiated Ae. albopictus males and 18% of cases in the inverse heterospecific matings. Moreover, our results also showed that these matings gave few eggs but were not viable. Finally, the results showed that whatever the type of mating crosses, females in cages previously crossed with males of another species can re-mate with males of their species and produce an equivalent amount of egg compared to females only mated with conspecific males. Despite the promiscuity of the males and females in small cages for three days, heterospecific mating between sterile male Ae. albopictus and female Ae aegypti, 95% of the females have not been inseminated suggesting that in the field the frequency satyrization would be very low. Full article
(This article belongs to the Special Issue Mosquito Handling, Transport, Release and Male Trapping Methods)
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19 pages, 2904 KiB  
Article
Quick Spreading of Populations of an Exotic Firefly throughout Spain and Their Recent Arrival in the French Pyrenees
by Marcel Koken, José Ramón Guzmán-Álvarez, Diego Gil-Tapetado, Miguel Angel Romo Bedate, Geneviève Laurent, Lucas Ezequiel Rubio, Segimon Rovira Comas, Nicole Wolffler, Fabien Verfaillie and Raphaël De Cock
Insects 2022, 13(2), 148; https://doi.org/10.3390/insects13020148 - 29 Jan 2022
Cited by 6 | Viewed by 7287
Abstract
In August 2018, a firefly (Coleoptera: Lampyridae) of American origin was observed in several localities in Girona (Catalonia, Spain) and was described as Photinus immigrans by Zaragoza-Caballero and Vinolas, 2018. Here, we show that this species dispersed very quickly throughout northeastern [...] Read more.
In August 2018, a firefly (Coleoptera: Lampyridae) of American origin was observed in several localities in Girona (Catalonia, Spain) and was described as Photinus immigrans by Zaragoza-Caballero and Vinolas, 2018. Here, we show that this species dispersed very quickly throughout northeastern Spain and was, in 2020, observed in the French Pyrenees. The animal’s quick progress is documented, and part of its biology is described (dispersion speed, land use, phenology, identification of all life stages). An additional population was localized in Extremadura, and its special status is discussed. We were able to determine its Argentinian–Uruguayan origin and propose, therefore, to consider Photinus immigrans as a synonym of Photinus signaticollis (Blanchard, 1846) (=Photinus immigrans Zaragoza-Caballero and Viñolas, 2018, syn. nov.). Our data clearly show that at least the Catalan and French populations are spreading very quickly and are able to settle permanently if adequate ecosystems are found. The species is highly expansive and may well be invasive; our citizen science platforms are ideally suited to monitor their progress throughout Spain and France. This is important for avoiding future ecological problems with diverse native faunas, such as glow-worms, fireflies and earthworms. If no ways are found to stop the species’ progression, the animals will quite probably invade substantial areas of France, Spain and the rest of Europe in the years to come. Full article
(This article belongs to the Special Issue Reproductive Behaviour in Insects and other Non-Marine Arthropods)
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26 pages, 821 KiB  
Article
Temperature-Specific and Sex-Specific Fitness Effects of Sympatric Mitochondrial and Mito-Nuclear Variation in Drosophila obscura
by Pavle Erić, Aleksandra Patenković, Katarina Erić, Marija Tanasković, Slobodan Davidović, Mina Rakić, Marija Savić Veselinović, Marina Stamenković-Radak and Mihailo Jelić
Insects 2022, 13(2), 139; https://doi.org/10.3390/insects13020139 - 28 Jan 2022
Cited by 6 | Viewed by 21918
Abstract
The adaptive significance of sympatric mitochondrial (mtDNA) variation and the role of selective mechanisms that maintain it are debated to this day. Isofemale lines of Drosophila obscura collected from four populations were backcrossed within populations to construct experimental lines, with all combinations of [...] Read more.
The adaptive significance of sympatric mitochondrial (mtDNA) variation and the role of selective mechanisms that maintain it are debated to this day. Isofemale lines of Drosophila obscura collected from four populations were backcrossed within populations to construct experimental lines, with all combinations of mtDNA Cyt b haplotypes and nuclear genetic backgrounds (nuDNA). Individuals of both sexes from these lines were then subjected to four fitness assays (desiccation resistance, developmental time, egg-to-adult viability and sex ratio) on two experimental temperatures to examine the role of temperature fluctuations and sex-specific selection, as well as the part that interactions between the two genomes play in shaping mtDNA variation. The results varied across populations and fitness components. In the majority of comparisons, they show that sympatric mitochondrial variants affect fitness. However, their effect should be examined in light of interactions with nuDNA, as mito-nuclear genotype was even more influential on fitness across all components. We found both sex-specific and temperature-specific differences in mitochondrial and mito-nuclear genotype ranks in all fitness components. The effect of temperature-specific selection was found to be more prominent, especially in desiccation resistance. From the results of different components tested, we can also infer that temperature-specific mito-nuclear interactions rather than sex-specific selection on mito-nuclear genotypes have a more substantial role in preserving mtDNA variation in this model species. Full article
(This article belongs to the Special Issue Selected Papers from the 1st International Electronic Conference on Entomology)
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