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Insects, Volume 13, Issue 1 (January 2022) – 105 articles

Cover Story (view full-size image): Fireflies are charismatic beetles with a fascinating biology and economic interest, yet their diversity is poorly studied, especially in the tropics, where they are most diverse. Here, by studying museum specimens, we discovered a new genus and three new species of fireflies endemic to the Amazon biome, which share in common a unique mating device on the last few segments of the abdomen. Our phylogenetic analyses based on morphological data suggest the new genus is related to Scissicauda, fireflies from the Atlantic Rainforest which also have mating clamps, although in a different arrangement. View this paper
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Review
Insect Rearing Techniques for Biological Control Programs, a Component of Sustainable Agriculture in Brazil
Insects 2022, 13(1), 105; https://doi.org/10.3390/insects13010105 - 17 Jan 2022
Cited by 1 | Viewed by 1235
Abstract
This article describes the importance of rearing insects, whether on a small scale for research or a large scale for mass rearing, for use in biological control (BC) programs with macro-organisms. These inter- or multidisciplinary research programs are necessarily long-term and depend on [...] Read more.
This article describes the importance of rearing insects, whether on a small scale for research or a large scale for mass rearing, for use in biological control (BC) programs with macro-organisms. These inter- or multidisciplinary research programs are necessarily long-term and depend on rearing techniques for their complete development. Some successful examples of BC in Brazil are presented, including case studies of Trichogramma spp. These required broad bioecological studies that provided the basis for both mass rearing and transfer of the necessary technology to farmers. This has allowed Brazil to occupy a leadership position in biological control in “Open Fields”. For example, about three million ha are being treated with Trichogramma galloi (a native parasitoid), and about three and a half million ha with Cotesia flavipes (an exotic parasitoid) to control Diatraea saccharalis, the sugarcane borer. These natural enemies are produced by commercial firms, or by laboratories in sugar and alcohol plants themselves, in the case of C. flavipes. Full article
(This article belongs to the Special Issue Rearing Techniques for Biocontrol Agents of Insects, Mites, and Weeds)
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Article
Decoyinine Induced Resistance in Rice against Small Brown Planthopper Laodelphax striatellus
Insects 2022, 13(1), 104; https://doi.org/10.3390/insects13010104 - 17 Jan 2022
Cited by 1 | Viewed by 674
Abstract
Induced resistance against SBPH via microbial pesticides is considered as an eco-friendly and promising management approach. In this study, the induced resistance against SBPH in rice seedling by a new potential microbial pesticide, decoyinine (DCY), a secondary metabolite produced by Streptomyces hygroscopicus, was [...] Read more.
Induced resistance against SBPH via microbial pesticides is considered as an eco-friendly and promising management approach. In this study, the induced resistance against SBPH in rice seedling by a new potential microbial pesticide, decoyinine (DCY), a secondary metabolite produced by Streptomyces hygroscopicus, was evaluated to investigate the effects of DCY on SBPH’s biological and population parameters along with defense-related physiological and biochemical indices in rice against SBPH feeding. We found that DCY has potential to improve rice resistance and significantly reduced the fecundity of SBPH. Laboratory results revealed that DCY treated rice significantly changed SBPH’s fecundity and population life table parameters. The concentrations of hydrogen peroxide (H2O2), soluble sugars and malondialdehyde (MDA) were significantly lower in DCY treated rice plants against SBPH infestation at 24, 48 and 96 hours post infestation (hpi), respectively. The concentrations of antioxidant enzymes, catalase (CAT) was significantly higher at 72 hpi, while super oxidase dismutase (SOD) and peroxidase (POD) concentrations were recorded higher at 96 hpi. The concentrations of synthases enzymes, phenyl alanine ammonia-lyase (PAL) was higher at 48 hpi, whereas polyphenol oxidase (PPO) concentration was maximum at 72 hpi against SBPH infestation. The results imply that DCY has unique properties to enhance rice resistance against SBPH by stimulating plant defensive responses. Microbial pesticides may be developed as an alternative to chemical pest control. Full article
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Article
Persistency of Indigenous and Exotic Entomopathogenic Fungi Isolates under Ultraviolet B (UV-B) Irradiation to Enhance Field Application Efficacy and Obtain Sustainable Control of the Red Palm Weevil
Insects 2022, 13(1), 103; https://doi.org/10.3390/insects13010103 - 17 Jan 2022
Viewed by 646
Abstract
The red palm weevil Rhynchophorus ferrugineus Olivier (Coleoptera: Dryophthoridae) has become a key invasive pest and major threat to the palm tree worldwide. Several entomopathogenic fungi are used in insect biological control programs. In the present study, persistency of different local and exotic [...] Read more.
The red palm weevil Rhynchophorus ferrugineus Olivier (Coleoptera: Dryophthoridae) has become a key invasive pest and major threat to the palm tree worldwide. Several entomopathogenic fungi are used in insect biological control programs. In the present study, persistency of different local and exotic fungal isolates of Beauveria bassiana and Metarhizium anisopliae was evaluated under UV-B irradiation with different exposure intervals. Several factors, including ultraviolet (UV) light, significantly decrease germination rate of fungi, as UV penetrates and damages their DNA. Several studies have investigated that UV-resistant conidia germinate better under harsh environmental conditions. Seven local and exotic fungi isolates (“BbSA-1”, “BbSA-2”, “BbSA-3”, “MaSA-1”, “BbIDN-1”, “MaIDN-1”, and “MaIDN-2”) were tested in the current study under UV-B irradiation having different UV exposure times (i.e., 15, 30, 60, 120, 180, 240, and 300 min). The colony-forming unit (CFU) in each isolate was used to calculate the survival rate. Results indicated that survival rate of all the isolates decreased under UV-B irradiation for all exposure times compared to no exposure to UV-B irradiation. The CFU number decreased as the exposure time increased. Fungi isolates “MaSA-1”, “BbSA-1”, “BbSA-2”, “MaIDN-1”, and “MaIDN-2” could persist after 300 min exposure to UV-B, while the remaining isolates, such as “BbIDN-1”, and “BbSA-3”, could not persist after 300 min exposure to UV-B. The ultimate objective of the present research was to explore an ultraviolet-tolerant fungal isolate that might be useful in the field application for the sustainable management of the red palm weevil, which has become a key invasive pest in many regions rather than its native range. Most of the fungus isolates studied in the present work were collected from Saudi Arabia’s Al-Qatif region, where the red palm weevil has infested more than ten thousand trees, worth millions of riyals. Full article
(This article belongs to the Collection Biocontrol and Behavioral Approaches to Manage Invasive Insects)
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Article
A New Cixiid Fossil Genus of the Tribe Acrotiarini from Mid-Cretaceous Burmese Amber (Insecta, Hemiptera, Fulgoromorpha)
Insects 2022, 13(1), 102; https://doi.org/10.3390/insects13010102 - 17 Jan 2022
Cited by 1 | Viewed by 643
Abstract
A new Burmese amber genus Maculixiusgen. nov. with its type species Maculixius jiewenaesp. nov. is described in the planthopper family Cixiidae. This new genus is unique in Burmese Cixiidae by its forewing venation, with Pcu and A1 merging in the middle [...] Read more.
A new Burmese amber genus Maculixiusgen. nov. with its type species Maculixius jiewenaesp. nov. is described in the planthopper family Cixiidae. This new genus is unique in Burmese Cixiidae by its forewing venation, with Pcu and A1 merging in the middle of clavus, the late bifurcation of ScP+R slightly after this level, and the early CuA forking well before this level. Although the head capsule is missing, it belongs to the recently described tribe Acrotiarini, based on the pentacarinated mesonotum and the distinctly arched RA on forewing with cell C1 wider submedially than apically. Morphological characteristics of Acrotiarini are discussed, and a key to identification of Acrotiarini genera is provided. The new taxon broadens the knowledge of the tribe, and it underlines the already great diversity of the family in the Cretaceous. Full article
(This article belongs to the Section Insect Systematics, Phylogeny and Evolution)
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Article
Five-Year Monitoring of a Desert Burrow-Dwelling Spider Following an Environmental Disaster Indicates Long-Term Impacts
Insects 2022, 13(1), 101; https://doi.org/10.3390/insects13010101 - 17 Jan 2022
Viewed by 1375
Abstract
Deserts are characterized by unpredictable precipitation and extreme temperatures. Their fauna and flora are sensitive to anthropogenic environmental changes, and often recover slowly from environmental disasters. The effects of oil spills on the biota of desert regions, however, have scarcely been studied. We [...] Read more.
Deserts are characterized by unpredictable precipitation and extreme temperatures. Their fauna and flora are sensitive to anthropogenic environmental changes, and often recover slowly from environmental disasters. The effects of oil spills on the biota of desert regions, however, have scarcely been studied. We predicted that terrestrial invertebrates suffer long-term negative effects from an oil spill, due to their close association with the substrate. Thus, we investigated the effects of two oil spills that occurred in 1975 and 2014 in the hyper-arid ‘Arava desert (Israel), on a spider that constructs silk-lined nests in burrows in compact, sandy soil in this extreme desert habitat. The spider, Sahastata aravaensis sp. nov. (Filistatidae), is described herein. We assessed spider burrow abundance in plots located in oil-contaminated and nearby uncontaminated clean soil (control) areas over five consecutive years and measured habitat characteristics in these plots. In the laboratory, we determined the preference of individuals for clean vs. oil-contaminated soil as a resting substrate. Finally, as this species was previously undescribed, we added a new species description. The abundance of Sahastata was significantly lower in oil-contaminated plots, and this was the case in the 40-year-old oil spill (1975) as well as in the recent one (2014). In laboratory tests, spiders showed a significant preference for the clean soil substrate over the oil-contaminated substrate. In the field, soil crust hardness and vegetation density did not differ significantly between oil-contaminated and control plots, but these measures were highly variable. The burrows were significantly clustered, suggesting that the young disperse only short distances. In the laboratory adult spiders did not dig burrows, perhaps indicating that adults remain permanently in their natal burrows and that in the field they may use vacant burrows. We conclude that Sahastata populations were affected negatively by the oil spills and these effects were long-lasting. We propose that by monitoring their spatial distribution, burrow-dwelling spiders such as Sahastata can be used as effective bioindicators of soil pollution in desert habitats. Full article
(This article belongs to the Special Issue Arthropods in Desert Ecosystems)
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Article
Bacterial Survey in the Guts of Domestic Silkworms, Bombyx mori L.
Insects 2022, 13(1), 100; https://doi.org/10.3390/insects13010100 - 17 Jan 2022
Viewed by 885
Abstract
Silkworm, Bombyx mori L., research involves studies on improving strains for enhanced sustainability of high-quality silk production. Several of these have investigated the factors affecting growth and development of silkworm larvae and cocoon characteristics that subsequently affect the yield and quality of silk. [...] Read more.
Silkworm, Bombyx mori L., research involves studies on improving strains for enhanced sustainability of high-quality silk production. Several of these have investigated the factors affecting growth and development of silkworm larvae and cocoon characteristics that subsequently affect the yield and quality of silk. The gut microbiota has been reported to impact growth and development of silkworms and has been linked, in particular, with absorption and utilization of nutrients and immunity to diseases. The silkworm strains maintained in the Philippines lack sufficient biological data for use in strain improvement. This prompted efforts to augment the data by profiling bacterial communities through high-throughput 16S rRNA gene amplicon sequencing and analysis in four of the local silkworm strains that are bred and maintained in the country. Results of the study showed that the four silkworm strains are abundant in bacteria that belong to the genera Pseudomonas, Sphingomonas, Delftia, Methylobacterium and Acinetobacter. Results also showed that bacterial diversity and evenness increase as larvae mature, which can be correlated to larval development and shifts in the amount and age of mulberry leaves the larvae consume. Full article
(This article belongs to the Special Issue Silkworm and Silk: Traditional and Innovative Applications)
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Article
Comparison of the Parasitization of Chelonus inanitus L. (Hymenoptera: Braconidae) in Two Spodoptera Pests and Evaluation of the Procedure for Its Production
Insects 2022, 13(1), 99; https://doi.org/10.3390/insects13010099 - 15 Jan 2022
Viewed by 755
Abstract
Chelonus inanitus (L.) is an egg-larval parasitoid of noctuids Spodoptera exigua (Hübner) and S. littoralis (Boisduval), whose mass rearing or real potential has not been targeted yet. To improve the rearing in the factitious host Ephestia kuehniella Zeller, we investigated the influence of [...] Read more.
Chelonus inanitus (L.) is an egg-larval parasitoid of noctuids Spodoptera exigua (Hübner) and S. littoralis (Boisduval), whose mass rearing or real potential has not been targeted yet. To improve the rearing in the factitious host Ephestia kuehniella Zeller, we investigated the influence of host age and number of females parasitizing simultaneously on the overall rearing success, the influence of host age on the life cycle, and the influence of host species on the parasitoid body size. The proportion of emerging C. inanitus was higher from young host eggs, but more females emerged from mature eggs. Under high parasitoid competition, we observed a reduction in non-parasitized hosts without reducing parasitoid emergence. The parasitoid life cycle was longer in females, but the mismatch between sexes was smaller in mature eggs. The parasitoid size was smaller in the factitious host than in the natural hosts. Under semi-field conditions, we investigated the competition among parasitoid females on the overall parasitism success. The reproductive parasitism was more successful in S. exigua than in S. littoralis, and the maximum emergence was reached with three and four females, respectively. The control of S. littoralis may be attributed to the high developmental mortality, a non-reproductive parasitism that is often underestimated. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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Article
Dominance of Fructose-Associated Fructobacillus in the Gut Microbiome of Bumblebees (Bombus terrestris) Inhabiting Natural Forest Meadows
Insects 2022, 13(1), 98; https://doi.org/10.3390/insects13010098 - 15 Jan 2022
Viewed by 849
Abstract
Bumblebees are key pollinators in agricultural landscapes. However, little is known about how gut microbial communities respond to anthropogenic changes. We used commercially produced colonies of buff-tailed bumblebees (Bombus terrestris) placed in three habitats. Whole guts (midgut, hindgut, and rectum) of [...] Read more.
Bumblebees are key pollinators in agricultural landscapes. However, little is known about how gut microbial communities respond to anthropogenic changes. We used commercially produced colonies of buff-tailed bumblebees (Bombus terrestris) placed in three habitats. Whole guts (midgut, hindgut, and rectum) of B. terrestris specimens were dissected from the body and analyzed using 16S phylogenetic community analysis. We observed significantly different bacterial community composition between the agricultural landscapes (apple orchards and oilseed rape (Brassica napus) fields) and forest meadows, whereas differences in gut communities between the orchards and oilseed rape fields were nonsignificant. Bee-specific bacterial genera such as Lactobacillus, Snodgrassella, and Gilliamella dominated gut communities of B. terrestris specimens. In contrast, the guts of B. terrestris from forest meadows were dominated by fructose-associated Fructobacillus spp. Bacterial communities of workers were the most diverse. At the same time, those of males and young queens were less diverse, possibly reflecting greater exposure to the colony’s inner environment compared to the environment outside the colony, as well as bumblebee age. Our results suggest that habitat quality, exposure to environmental microbes, nectar quality and accessibility, and land use significantly affect gut bacterial composition in B. terrestris. Full article
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Article
Evaluation of Optimal Reference Genes for qRT-PCR Analysis in Hyphantria cunea (Drury)
Insects 2022, 13(1), 97; https://doi.org/10.3390/insects13010097 - 14 Jan 2022
Cited by 1 | Viewed by 355
Abstract
The relative quantification of gene expression is mainly achieved through reverse transcription-quantitative PCR (qRT-PCR); however, its reliability and precision rely on proper data normalization using one or more optimal reference genes. Hyphantria cunea (Drury) has been an invasive pest of forest trees, ornamental [...] Read more.
The relative quantification of gene expression is mainly achieved through reverse transcription-quantitative PCR (qRT-PCR); however, its reliability and precision rely on proper data normalization using one or more optimal reference genes. Hyphantria cunea (Drury) has been an invasive pest of forest trees, ornamental plants, and fruit trees in China for many years. Currently, the molecular physiological role of reference genes in H. cunea is unclear, which hinders functional gene study. Therefore, eight common reference genes, RPS26, RPL13, UBI, AK, RPS15, EIF4A, β-actin, α-tub, were selected to evaluate levels of gene expression stability when subjected to varied experimental conditions, including developmental stage and gender, different tissues, larvae reared on different hosts and different larval density. The geNorm, BestKeeper, ΔCt method, and NormFinder statistical algorithms were used to normalize gene transcription data. Furthermore, the stability/suitability of these candidates was ranked overall by RefFinder. This study provides a comprehensive evaluation of reference genes in H. cunea and could help select reference genes for other Lepidoptera species. Full article
(This article belongs to the Section Insect Molecular Biology and Genomics)
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Article
Identification and Expression Profile of Chemosensory Receptor Genes in Aromia bungii (Faldermann) Antennal Transcriptome
Insects 2022, 13(1), 96; https://doi.org/10.3390/insects13010096 - 14 Jan 2022
Viewed by 465
Abstract
The red-necked longicorn beetle, Aromia bungii (Faldermann) (Coleoptera: Cerambycidae), is a major destructive, wood-boring pest, which is widespread throughout the world. The sex pheromone of A. bungii was reported earlier; however, the chemosensory mechanism of the beetle remains almost unknown. In this study, [...] Read more.
The red-necked longicorn beetle, Aromia bungii (Faldermann) (Coleoptera: Cerambycidae), is a major destructive, wood-boring pest, which is widespread throughout the world. The sex pheromone of A. bungii was reported earlier; however, the chemosensory mechanism of the beetle remains almost unknown. In this study, 45 AbunORs, 6 AbunGRs and 2 AbunIRs were identified among 42,197 unigenes derived from the antennal transcriptome bioinformatic analysis of A. bungii adults. The sequence of putative Orco (AbunOR25) found in this study is highly conserved with the known Orcos from other Coleoptera species, and these Orco genes might be potentially used as target genes for the future development of novel and effective control strategies. Tissue expression analysis showed that 29 AbunOR genes were highly expressed in antennae, especially in the antennae of females, which was consistent with the idea that females might express more pheromone receptors for sensing pheromones, especially the sex pheromones produced by males. AbunOR5, 29, 31 and 37 were clustered with the pheromone receptors of the cerambycid Megacyllene caryae, suggesting that they might be putative pheromone receptors of A. bungii. All six AbunGRs were highly expressed in the mouthparts, indicating that these GRs may be involved in the taste perception process. Both AbunIRs were shown to be female-mouthparts-biased, suggesting that they might also be related to the tasting processes. Our study provides some basic information towards a deeper understanding of the chemosensing mechanism of A. bungii at a molecular level. Full article
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The First Report of the Genera Abaria and Drepanocentron (Trichoptera: Xiphocentronidae) from China, with Descriptions of Two New Species
Insects 2022, 13(1), 95; https://doi.org/10.3390/insects13010095 - 14 Jan 2022
Viewed by 294
Abstract
The genera Abaria Mosely 1948 and Drepanocentron Schmid 1982 are recorded in China for the first time. In this study, two new species, Abaria herringbona sp. nov., from Guang-xi, and Drepanocentron fuxiensis sp. nov., from An-hui, are described and illustrated. Male genitalia of [...] Read more.
The genera Abaria Mosely 1948 and Drepanocentron Schmid 1982 are recorded in China for the first time. In this study, two new species, Abaria herringbona sp. nov., from Guang-xi, and Drepanocentron fuxiensis sp. nov., from An-hui, are described and illustrated. Male genitalia of these two new species is distinguishable from those of other Abaria and Drepanocentron species. In addition, Melanotrichia attia Malicky & Chantaramongkol 1992 is a new record for the Chinese caddisfly fauna. Full article
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Article
Changes in Biomass and Diversity of Soil Macrofauna along a Climatic Gradient in European Boreal Forests
Insects 2022, 13(1), 94; https://doi.org/10.3390/insects13010094 - 14 Jan 2022
Viewed by 508
Abstract
Latitudinal gradients allow insights into the factors that shape ecosystem structure and delimit ecosystem processes, particularly climate. We asked whether the biomass and diversity of soil macrofauna in boreal forests change systematically along a latitudinal gradient spanning from 60° N to 69° N. [...] Read more.
Latitudinal gradients allow insights into the factors that shape ecosystem structure and delimit ecosystem processes, particularly climate. We asked whether the biomass and diversity of soil macrofauna in boreal forests change systematically along a latitudinal gradient spanning from 60° N to 69° N. Invertebrates (3697 individuals) were extracted from 400 soil samples (20 × 20 cm, 30 cm depth) collected at ten sites in 2015–2016 and then weighed and identified. We discovered 265 species living in soil and on the soil surface; their average density was 0.486 g d·w·m−2. The species-level diversity decreased from low to high latitudes. The biomass of soil macrofauna showed no latitudinal changes in early summer but decreased towards the north in late summer. This variation among study sites was associated with the decrease in mean annual temperature by ca 5 °C and with variation in fine root biomass. The biomass of herbivores and fungivores decreased towards the north, whereas the biomass of detritivores and predators showed no significant latitudinal changes. This variation in latitudinal biomass patterns among the soil macrofauna feeding guilds suggests that these guilds may respond differently to climate change, with poorly understood consequences for ecosystem structure and functions. Full article
(This article belongs to the Section Insect Ecology, Diversity and Conservation)
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Communication
Isolation of Beauveria Strains and Their Potential as Control Agents for Lema bilineata Germar (Coleoptera: Chrysomelidae)
Insects 2022, 13(1), 93; https://doi.org/10.3390/insects13010093 - 14 Jan 2022
Viewed by 356
Abstract
Lema bilineata Germar (Coleoptera: Chrysomelidae) was recently reported to damage Physalis peruviana crops in Brazil. Given the potential for inflicting damage on other Solanaceae species and the lack of alternatives for controlling this pest, we assessed the pathogenicity of 15 Beauveria isolates against [...] Read more.
Lema bilineata Germar (Coleoptera: Chrysomelidae) was recently reported to damage Physalis peruviana crops in Brazil. Given the potential for inflicting damage on other Solanaceae species and the lack of alternatives for controlling this pest, we assessed the pathogenicity of 15 Beauveria isolates against L. bilineata adults in vitro. In addition, three of these isolates were tested for their ovicidal effect against L. bilineata eggs. Fungal strains were isolated from mummified corpses of L. bilineata collected in a non-commercial field in Paraná, Brazil. The isolates were identified as Beauveria bassiana using molecular markers. Lema bilineata adults were susceptible to conidial suspensions of all these isolates at a concentration of 108 conidia mL−1. Deaths caused by fungal extrusion were confirmed. Three strains were found to be more virulent against L. bilineata adults and showed ovicidal effects. This is the first study on entomopathogenic fungi isolated from dead insects collected from P. peruviana crops and tested against L. bilineata carried out in Brazil. The results obtained in the laboratory indicate the high potential of the use of three B. bassiana strains against L. bilineata as a biocontrol agent. Full article
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Article
Species-Specificity in Thermopreference and CO2-Gated Heat-Seeking in Culex Mosquitoes
Insects 2022, 13(1), 92; https://doi.org/10.3390/insects13010092 - 14 Jan 2022
Cited by 1 | Viewed by 516
Abstract
Combining thermopreference (Tp) and CO2-gated heat-seeking assays, we studied the thermal preferendum and response to thermal cues in three Culex mosquito species exhibiting differences in native habitat and host preference (e.g., biting cold and/or warm-blooded animals). Results show that [...] Read more.
Combining thermopreference (Tp) and CO2-gated heat-seeking assays, we studied the thermal preferendum and response to thermal cues in three Culex mosquito species exhibiting differences in native habitat and host preference (e.g., biting cold and/or warm-blooded animals). Results show that these species differ in both Tp and heat-seeking behavior. In particular, we found that Culex territans, which feed primarily on cold-blood hosts, did not respond to heat during heat-seeking assays, regardless of the CO2 concentration, but exhibited an intermediate Tp during resting. In contrast, Cx. quinquefasciatus, which feeds on warm blooded hosts, sought the coolest locations on a thermal gradient and responded only moderately to thermal stimuli when paired with CO2 at higher concentrations. The third species, Cx. tarsalis, which has been shown to feed on a wide range of hosts, responded to heat when paired with high CO2 levels and exhibited a high Tp. This study provides the first insights into the role of heat and CO2 in the host seeking behavior of three disease vectors in the Culex genus and highlights differences in preferred resting temperatures. Full article
(This article belongs to the Collection Insect Sensory Biology)
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Efficacy of Helicoverpa Armigera Nucleopolyhedrovirus on Soybean for Control of Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) in Arkansas Agriculture
Insects 2022, 13(1), 91; https://doi.org/10.3390/insects13010091 - 13 Jan 2022
Viewed by 358
Abstract
Helicoverpa armigera nucleopolyhedrovirus (HearNPV) is a naturally occurring virus commercially produced for control of Heliothines, including Helicoverpa zea. One drawback with using this virus for control has been the slower time to mortality compared with synthetic insecticides. However, a new formulation (Heligen [...] Read more.
Helicoverpa armigera nucleopolyhedrovirus (HearNPV) is a naturally occurring virus commercially produced for control of Heliothines, including Helicoverpa zea. One drawback with using this virus for control has been the slower time to mortality compared with synthetic insecticides. However, a new formulation (Heligen®) has anecdotally been thought to result in quicker mortality than previously observed. The objective of this study was to evaluate percent defoliation, the efficacy of HearNPV on mortality for each H. zea larval instar, and the potential for control of a second infestation. Fourteen days after the first infestation, all plants were re-infested with a second instar larva to simulate a second infestation. Helicoverpa armigera nucleopolyhedrovirus was effective at killing 1st–3rd instars, resulting in 99% mortality over 4–6 days. However, 4th and 5th instar mortality only reached 35%. Second infestation larvae died between 3.4 and 3.8 days, significantly faster than the 1st infestation of 2nd instars, which had a mean time to mortality of 4.9 days. An increase in mortality rate is probably due to increasing viral concentrations after viral replication within the first hosts. Final defoliation percentages were significantly smaller in the treated plants versus the untreated plants. Only 3rd and 4th instar larvae caused percent defoliation to exceed the current Arkansas action threshold of 40%. Helicoverpa armigera nucleopolyhedrovirus in the Heligen formulation can control 1st–3rd instars within 4–6 days, while keeping defoliation below the action threshold of 40%. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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Article
Herbivore-Induced Rice Volatiles Attract and Affect the Predation Ability of the Wolf Spiders, Pirata subpiraticus and Pardosa pseudoannulata
Insects 2022, 13(1), 90; https://doi.org/10.3390/insects13010090 - 13 Jan 2022
Viewed by 363
Abstract
Spiders are important natural enemies of rice pests. Studying the effects of herbivore-induced rice volatiles on spider attraction and predation ability may lead to safer methods for pest prevention and control. In this study, four-arm olfactometer, predation ability experiment, and field trapping experiment [...] Read more.
Spiders are important natural enemies of rice pests. Studying the effects of herbivore-induced rice volatiles on spider attraction and predation ability may lead to safer methods for pest prevention and control. In this study, four-arm olfactometer, predation ability experiment, and field trapping experiment were used to evaluate the effects of herbivore-induced rice volatiles on Pirata subpiraticus Bösenberg et Strand (Araneae: Lycosidae) and Pardosa pseudoannulata Bösenberg et Strand (Araneae: Lycosidae). The 0.5 μg/μL linalool concentration was attractive, and also shortened the predation latency in male P. subpiraticus and female P. pseudoannulata. The 0.5 μg/μL linalool concentration increased the daily predation capacity of female P. pseudoannulata. Male P. pseudoannulata were attracted to 1.0 g/L methyl salicylate, which also shortened their predation latency. In field experiments, methyl salicylate and linalool were effective for trapping spiders. Herbivore-induced rice volatiles attract rice field spiders and affect their predatory ability. These results suggest that herbivore-induced rice volatiles can be used to attract spiders and provide improved control of rice pests. Full article
(This article belongs to the Special Issue Physical and Chemical Interactions between Insects and Plants)
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Article
Use of Pyriproxyfen to Induce Oogenesis in Diapausing Megacopta cribraria (Heteroptera: Plataspidae), and Evaluation of Pyriproxyfen-Induced Eggs for Rearing the Parasitoid Paratelenomus saccharalis (Hymenoptera: Scelionidae)
Insects 2022, 13(1), 89; https://doi.org/10.3390/insects13010089 - 13 Jan 2022
Viewed by 337
Abstract
The mass rearing of hymenopteran egg parasitoids requires an abundant supply of host eggs. The onset of reproductive diapause and subsequent decline in egg production poses a challenge for parasitoid rearing when using host colonies augmented by field-collected insects. We investigated the application [...] Read more.
The mass rearing of hymenopteran egg parasitoids requires an abundant supply of host eggs. The onset of reproductive diapause and subsequent decline in egg production poses a challenge for parasitoid rearing when using host colonies augmented by field-collected insects. We investigated the application of pyriproxyfen, a juvenile hormone analog, to induce oviposition in diapausing adult kudzu bugs, Megacopta cribraria (Fabricius) (Heteroptera: Plataspidae), and the use of eggs produced by pyriproxyfen-treated kudzu bugs to rear the egg parasitoid, Paratelenomus saccharalis (Dodd) (Hymenoptera: Scelionidae). The effects of pyriproxyfen and photoperiod treatments on host mortality, egg production, and rates of parasitoid eclosion from the eggs were used to calculate the parasitoid yield for the different treatment regimes. A combination of pyriproxyfen and a long-day photoperiod increased the parasitoid yield by 87% compared to acetone and a long-day photoperiod. The general applicability of JH-analog mediated egg production for parasitoid rearing is discussed. Full article
(This article belongs to the Special Issue Rearing Techniques for Biocontrol Agents of Insects, Mites, and Weeds)
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Article
Sampling Optimization and Crop Interface Effects on Lygus lineolaris Populations in Southeastern USA Cotton
Insects 2022, 13(1), 88; https://doi.org/10.3390/insects13010088 - 13 Jan 2022
Viewed by 423
Abstract
Tarnished plant bug, Lygus lineolaris (Hemiptera: Miridae), is an economically damaging pest in cotton production systems across the southern United States. We systematically scouted 120 commercial cotton fields across five southeastern states during susceptible growth stages in 2019 and 2020 to investigate sampling [...] Read more.
Tarnished plant bug, Lygus lineolaris (Hemiptera: Miridae), is an economically damaging pest in cotton production systems across the southern United States. We systematically scouted 120 commercial cotton fields across five southeastern states during susceptible growth stages in 2019 and 2020 to investigate sampling optimization and the effect of interface crop and landscape composition on L. lineolaris abundance. Variance component analysis determined field and within-field spatial scales, compared with agricultural district and state, accounted for more variation in L. lineolaris density using sweep net and drop cloth sampling. This result highlights the importance of field-level scouting efforts. Using within-field samples, a fixed-precision sampling plan determined 8 and 23 sampling units were needed to determine L. lineolaris population estimates with 0.25 precision for sweep net (100 sweeps per unit) and drop cloth (1.5 row-m per unit) sampling, respectively. A spatial Bayesian hierarchical model was developed to determine local landscape (<0.5 km from field edges) effects on L. lineolaris in cotton. The proportion of agricultural area and double-crop wheat and soybeans were positively associated with L. lineolaris density, and fields with more contiguous cotton areas negatively predicted L. lineolaris populations. These results will improve L. lineolaris monitoring programs and treatment management decisions in southeastern USA cotton. Full article
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Article
Effects of Acetamiprid at Low and Median Lethal Concentrations on the Development and Reproduction of the Soybean Aphid Aphis glycines
Insects 2022, 13(1), 87; https://doi.org/10.3390/insects13010087 - 13 Jan 2022
Cited by 1 | Viewed by 351
Abstract
The soybean aphid Aphis glycines Matsumura (Hemiptera: Aphididae) is a major pest of soybean and poses a serious threat to soybean production. Studies on the effect of acetamiprid on the life table parameters of A. glycines, provide important information for the effective [...] Read more.
The soybean aphid Aphis glycines Matsumura (Hemiptera: Aphididae) is a major pest of soybean and poses a serious threat to soybean production. Studies on the effect of acetamiprid on the life table parameters of A. glycines, provide important information for the effective management of this pest. We found that exposure to acetamiprid at LC50 significantly extended the mean generation time, adult pre-reproductive period, and total pre-reproduction period compared with the control, whereas exposure to acetamiprid at LC30 significantly shortened these periods. Exposure to acetamiprid at both LC30 and LC50 significantly decreased the fecundity of the female adult, net reproductive rate, intrinsic rate of increase, and finite rate of increase compared with the control. The probability of attaining the adult stage was 0.51, 0.38, and 0.86 for a newly born nymph from the LC30 acetamiprid treatment group, LC50 acetamiprid treatment group, and control group, respectively. Acetamiprid at both LC50 and LC30 exerted stress effects on A. glycines, with the LC50 treatment significantly decreased the growth rate compared with the LC30 treatment. The present study provides reference data that could facilitate the exploration of the effects of acetamiprid on A. glycines in the field. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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Article
The Diversity of Bacteria Associated with the Invasive Gall Wasp Dryocosmus kuriphilus, Its Galls and a Specialist Parasitoid on Chestnuts
Insects 2022, 13(1), 86; https://doi.org/10.3390/insects13010086 - 13 Jan 2022
Viewed by 404
Abstract
Dryocosmus kuriphilus (Hymenoptera: Cynipidae) induces galls on chestnut trees, which results in massive yield losses worldwide. Torymus sinensis (Hymenoptera: Torymidae) is a host-specific parasitoid that phenologically synchronizes with D. kuriphilus. Bacteria play important roles in the life cycle of galling insects. The [...] Read more.
Dryocosmus kuriphilus (Hymenoptera: Cynipidae) induces galls on chestnut trees, which results in massive yield losses worldwide. Torymus sinensis (Hymenoptera: Torymidae) is a host-specific parasitoid that phenologically synchronizes with D. kuriphilus. Bacteria play important roles in the life cycle of galling insects. The aim of this research is to investigate the bacterial communities and predominant bacteria of D. kuriphilus, T. sinensis, D. kuriphilus galls and the galled twigs of Castanea mollissima. We sequenced the V5–V7 region of the bacterial 16S ribosomal RNA in D. kuriphilus, T. sinensis, D. kuriphilus galls and galled twigs using high-throughput sequencing for the first time. We provide the first evidence that D. kuriphilus shares most bacterial species with T. sinensis, D. kuriphilus galls and galled twigs. The predominant bacteria of D. kuriphilus are Serratia sp. and Pseudomonas sp. Furthermore, the bacterial community structures of D. kuriphilus and T. sinensis clearly differ from those of the other groups. Many species of the Serratia and Pseudomonas genera are plant pathogenic bacteria, and we suggest that D. kuriphilus may be a potential vector of plant pathogens. Furthermore, a total of 111 bacteria are common to D. kuriphilus adults, T. sinensis, D. kuriphilus galls and galled twigs, and we suggest that the bacteria may transmit horizontally among D. kuriphilus, T. sinensis, D. kuriphilus galls and galled twigs on the basis of their ecological associations. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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Article
Detection of Yeast-like Symbionts in Brown Planthopper Reared on Different Resistant Rice Varieties Combining DGGE and Absolute Quantitative Real-Time PCR
Insects 2022, 13(1), 85; https://doi.org/10.3390/insects13010085 - 13 Jan 2022
Viewed by 272
Abstract
The brown planthopper (BPH), Nilaparvata lugens, is a serious pest of rice throughout Asia. Yeast-like symbionts (YLS) are endosymbionts closely linked with the development of BPH and the adapted mechanism of BPH virulence to resistant plants. In this study, we used semi-quantitative [...] Read more.
The brown planthopper (BPH), Nilaparvata lugens, is a serious pest of rice throughout Asia. Yeast-like symbionts (YLS) are endosymbionts closely linked with the development of BPH and the adapted mechanism of BPH virulence to resistant plants. In this study, we used semi-quantitative DGGE and absolute quantitative real-time PCR (qPCR) to quantify the number of the three YLS strains (Ascomycetes symbionts, Pichia-like symbionts, and Candida-like symbionts) that typically infect BPH in the nymphal stages and in newly emerged female adults. The quantities of each of the three YLS assessed increased in tandem with the developing nymphal instar stages, peaking at the fourth instar stage, and then declined significantly at the fifth instar stage. However, the amount of YLS present recovered sharply within the emerging adult females. Additionally, we estimated the quantities of YLS for up to eight generations after their inoculation onto resistant cultivars (Mudgo, ASD7, and RH) to reassociate the dynamics of YLS with the fitness of BPH. The minimum number of each YLS was detected in the second generation and gradually increased from the third generation with regard to resistant rice varieties. In addition, the Ascomycetes symbionts of YLS were found to be the most abundant of the three YLS strains tested for all of the development stages of BPH. Full article
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Review
Nitrogen Acquisition Strategies Mediated by Insect Symbionts: A Review of Their Mechanisms, Methodologies, and Case Studies
Insects 2022, 13(1), 84; https://doi.org/10.3390/insects13010084 - 12 Jan 2022
Viewed by 461
Abstract
Nitrogen is usually a restrictive nutrient that affects the growth and development of insects, especially of those living in low nitrogen nutrient niches. In response to the low nitrogen stress, insects have gradually developed symbiont-based stress response strategies—biological nitrogen fixation and nitrogenous waste [...] Read more.
Nitrogen is usually a restrictive nutrient that affects the growth and development of insects, especially of those living in low nitrogen nutrient niches. In response to the low nitrogen stress, insects have gradually developed symbiont-based stress response strategies—biological nitrogen fixation and nitrogenous waste recycling—to optimize dietary nitrogen intake. Based on the above two patterns, atmospheric nitrogen or nitrogenous waste (e.g., uric acid, urea) is converted into ammonia, which in turn is incorporated into the organism via the glutamine synthetase and glutamate synthase pathways. This review summarized the reaction mechanisms, conventional research methods and the various applications of biological nitrogen fixation and nitrogenous waste recycling strategies. Further, we compared the bio-reaction characteristics and conditions of two strategies, then proposed a model for nitrogen provisioning based on different strategies. Full article
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Article
Neglected Very Long-Chain Hydrocarbons and the Incorporation of Body Surface Area Metrics Reveal Novel Perspectives for Cuticular Profile Analysis in Insects
Insects 2022, 13(1), 83; https://doi.org/10.3390/insects13010083 - 12 Jan 2022
Viewed by 428
Abstract
Most of our knowledge on insect cuticular hydrocarbons (CHCs) stems from analytical techniques based on gas-chromatography coupled with mass spectrometry (GC-MS). However, this method has its limits under standard conditions, particularly in detecting compounds beyond a chain length of around C40. Here, we [...] Read more.
Most of our knowledge on insect cuticular hydrocarbons (CHCs) stems from analytical techniques based on gas-chromatography coupled with mass spectrometry (GC-MS). However, this method has its limits under standard conditions, particularly in detecting compounds beyond a chain length of around C40. Here, we compare the CHC chain length range detectable by GC-MS with the range assessed by silver-assisted laser desorption/ionization mass spectrometry (Ag-LDI-MS), a novel and rarely applied technique on insect CHCs, in seven species of the order Blattodea. For all tested species, we unveiled a considerable range of very long-chain CHCs up to C58, which are not detectable by standard GC-MS technology. This indicates that general studies on insect CHCs may frequently miss compounds in this range, and we encourage future studies to implement analytical techniques extending the conventionally accessed chain length range. Furthermore, we incorporate 3D scanned insect body surface areas as an additional factor for the comparative quantification of extracted CHC amounts between our study species. CHC quantity distributions differed considerably when adjusted for body surface areas as opposed to directly assessing extracted CHC amounts, suggesting that a more accurate evaluation of relative CHC quantities can be achieved by taking body surface areas into account. Full article
(This article belongs to the Special Issue Hydrocarbons in Insects: Advances and Pitfalls)
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Article
Peering into the Darkness: DNA Barcoding Reveals Surprisingly High Diversity of Unknown Species of Diptera (Insecta) in Germany
Insects 2022, 13(1), 82; https://doi.org/10.3390/insects13010082 - 12 Jan 2022
Cited by 2 | Viewed by 1564
Abstract
Determining the size of the German insect fauna requires better knowledge of several megadiverse families of Diptera and Hymenoptera that are taxonomically challenging. This study takes the first step in assessing these “dark taxa” families and provides species estimates for four challenging groups [...] Read more.
Determining the size of the German insect fauna requires better knowledge of several megadiverse families of Diptera and Hymenoptera that are taxonomically challenging. This study takes the first step in assessing these “dark taxa” families and provides species estimates for four challenging groups of Diptera (Cecidomyiidae, Chironomidae, Phoridae, and Sciaridae). These estimates are based on more than 48,000 DNA barcodes (COI) from Diptera collected by Malaise traps that were deployed in southern Germany. We assessed the fraction of German species belonging to 11 fly families with well-studied taxonomy in these samples. The resultant ratios were then used to estimate the species richness of the four “dark taxa” families (DT families hereafter). Our results suggest a surprisingly high proportion of undetected biodiversity in a supposedly well-investigated country: at least 1800–2200 species await discovery in Germany in these four families. As this estimate is based on collections from one region of Germany, the species count will likely increase with expanded geographic sampling. Full article
(This article belongs to the Special Issue Diptera Diversity in Space and Time)
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Article
Exploring Higher-Order Conceptual Learning in an Arthropod with a Large Multisensory Processing Center
Insects 2022, 13(1), 81; https://doi.org/10.3390/insects13010081 - 12 Jan 2022
Viewed by 433
Abstract
Comparative cognition aims to understand the evolutionary history and current function of cognitive abilities in a variety of species with diverse natural histories. One characteristic often attributed to higher cognitive abilities is higher-order conceptual learning, such as the ability to learn concepts independent [...] Read more.
Comparative cognition aims to understand the evolutionary history and current function of cognitive abilities in a variety of species with diverse natural histories. One characteristic often attributed to higher cognitive abilities is higher-order conceptual learning, such as the ability to learn concepts independent of stimuli—e.g., ‘same’ or ‘different’. Conceptual learning has been documented in honeybees and a number of vertebrates. Amblypygids, nocturnal enigmatic arachnids, are good candidates for higher-order learning because they are excellent associational learners, exceptional navigators, and they have large, highly folded mushroom bodies, which are brain regions known to be involved in learning and memory in insects. In Experiment 1, we investigate if the amblypygid Phrynus marginimaculatus can learn the concept of same with a delayed odor matching task. In Experiment 2, we test if Paraphrynus laevifrons can learn same/different with delayed tactile matching and nonmatching tasks before testing if they can transfer this learning to a novel cross-modal odor stimulus. Our data provide no evidence of conceptual learning in amblypygids, but more solid conclusions will require the use of alternative experimental designs to ensure our negative results are not simply a consequence of the designs we employed. Full article
(This article belongs to the Collection Insect Senses: From Perception to Cognition)
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Article
Optimising Vine Weevil, Otiorhynchus sulcatus F. (Coleoptera: Curculionidae), Monitoring Tool Design
Insects 2022, 13(1), 80; https://doi.org/10.3390/insects13010080 - 12 Jan 2022
Viewed by 603
Abstract
Vine weevil, Otiorhynchus sulcatus F. (Coleoptera: Curculionidae), is an economically important insect pest of horticultural crops. To identify an effective and reliable monitoring system for adult vine weevil, this study investigated the influence of colour, height and entrance position on the efficacy of [...] Read more.
Vine weevil, Otiorhynchus sulcatus F. (Coleoptera: Curculionidae), is an economically important insect pest of horticultural crops. To identify an effective and reliable monitoring system for adult vine weevil, this study investigated the influence of colour, height and entrance position on the efficacy of a model monitoring tool using modified paper cups as refuges. Vine weevil preferences were determined by the number of individuals recorded within a refuge. When provided with a binary choice between black or white refuges, vine weevil adults showed a preference for black refuges. Vine weevils provided with a range of coloured refuges (blue, green, red and yellow) in addition to black and white refuges showed a preference for black and blue over the other colours and white refuges in group choice experiments. Refuge height and entrance position also influenced vine weevil behaviour with individuals exhibiting a preference for taller refuges and those with entrance openings around the refuge base. These results provide insights into refuge selection by adult vine weevils, which can be exploited to improve monitoring tool design. The importance of developing an effective monitoring tool for vine weevil adults as part of an integrated pest management programme is discussed. Full article
(This article belongs to the Collection Integrated Pest Management Strategies for Horticultural Crops)
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Article
Climate Change Increases the Expansion Risk of Helicoverpa zea in China According to Potential Geographical Distribution Estimation
Insects 2022, 13(1), 79; https://doi.org/10.3390/insects13010079 - 11 Jan 2022
Viewed by 467
Abstract
Helicoverpa zea, a well-documented and endemic pest throughout most of the Americas, affecting more than 100 species of host plants. It is a quarantine pest according to the Asia and Pacific Plant Protection Commission (APPPC) and the catalog of quarantine pests for [...] Read more.
Helicoverpa zea, a well-documented and endemic pest throughout most of the Americas, affecting more than 100 species of host plants. It is a quarantine pest according to the Asia and Pacific Plant Protection Commission (APPPC) and the catalog of quarantine pests for plants imported to the People’s Republic of China. Based on 1781 global distribution records of H. zea and eight bioclimatic variables, the potential geographical distributions (PGDs) of H. zea were predicted by using a calibrated MaxEnt model. The contribution rate of bioclimatic variables and the jackknife method were integrated to assess the significant variables governing the PGDs. The response curves of bioclimatic variables were quantitatively determined to predict the PGDs of H. zea under climate change. The results showed that: (1) four out of the eight variables contributed the most to the model performance, namely, mean diurnal range (bio2), precipitation seasonality (bio15), precipitation of the driest quarter (bio17) and precipitation of the warmest quarter (bio18); (2) PGDs of H. zea under the current climate covered 418.15 × 104 km2, and were large in China; and (3) future climate change will facilitate the expansion of PGDs for H. zea under shared socioeconomic pathways (SSP) 1-2.6, SSP2-4.5, and SSP5-8.5 in both the 2030s and 2050s. The conversion of unsuitable to low suitability habitat and moderately to high suitability habitat increased by 8.43% and 2.35%, respectively. From the present day to the 2030s, under SSP1-2.6, SSP2-4.5 and SSP5-8.5, the centroid of the suitable habitats of H. zea showed a general tendency to move eastward; from 2030s to the 2050s, under SSP1-2.6 and SSP5-8.5, it moved southward, and it moved slightly northward under SSP2-4.5. According to bioclimatic conditions, H. zea has a high capacity for colonization by introduced individuals in China. Customs ports should pay attention to host plants and containers of H. zea and should exchange information to strengthen plant quarantine and pest monitoring, thus enhancing target management. Full article
(This article belongs to the Topic Insects in Sustainable Agroecosystems)
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Article
Thelytokous Reproduction of Onion Thrips, Thrips tabaci Lindeman 1889, Infesting Welsh Onion and Genetic Variation among Their Subpopulations
Insects 2022, 13(1), 78; https://doi.org/10.3390/insects13010078 - 11 Jan 2022
Viewed by 473
Abstract
Parthenogenesis is not uncommon in thrips. This asexual reproduction produces males (arrhenotokous) or female (thelytokous). Only females are found in the onion thrips (Thrips tabaci Lindeman 1889) infesting Welsh onion (Allium fistulosum) in several areas of Korea. To determine the [...] Read more.
Parthenogenesis is not uncommon in thrips. This asexual reproduction produces males (arrhenotokous) or female (thelytokous). Only females are found in the onion thrips (Thrips tabaci Lindeman 1889) infesting Welsh onion (Allium fistulosum) in several areas of Korea. To determine the reproduction mode of T. tabaci, thrips infesting Welsh onion were collected from different localities in Korea. Cytochrome oxidase I (COI) sequences were then assessed. Results showed that all test local populations had signature motif specific to a thelytokous type. These COI sequences were clustered with other thelytokous populations separated from arrhenotokous T. tabaci populations. In a laboratory test, individual rearing produced female progeny without any males. These results support that Korean onion thrips infesting Welsh onion have the thelytokous type of parthenogenesis. Local thrips populations exhibited significant variations in susceptibility to chemical and biological insecticides. Random amplified polymorphic DNA (RAPD) analysis indicated genetic variations of local populations. However, the genetic distance estimated from RAPD was independent of the actual distance among different local populations. These results suggest that genetic variations of T. tabaci are arisen from population subdivision due to asexual thelytokous reproductive mode. Full article
(This article belongs to the Special Issue Economic Pest Thrips: Biology, Ecology, and Population Genetics)
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Article
Basic Studies Aiming at Orius minutus (Hemiptera: Anthocoridae) Mass-Rearing
Insects 2022, 13(1), 77; https://doi.org/10.3390/insects13010077 - 10 Jan 2022
Viewed by 388
Abstract
This study presented biological and economic data for the mass-rearing of Orius minutus in Korea. Simplifying the mass-rearing process through an alternative diet and an artificial oviposition substrate is a prerequisite for enhancing the usability of this insect as a biological control agent. [...] Read more.
This study presented biological and economic data for the mass-rearing of Orius minutus in Korea. Simplifying the mass-rearing process through an alternative diet and an artificial oviposition substrate is a prerequisite for enhancing the usability of this insect as a biological control agent. We compare the hatch rate of O. minutus eggs deposited on a plant substrate with that of eggs deposited on two artificial substrates, cork sheets and rubber. The results indicate that cork sheet is the most cost-effective artificial oviposition substrate for the mass-rearing of O. minutus. We also examine five feeding treatments that included two types of brine shrimp eggs and eggs of Ephestia cautella to compare the number of eggs laid in the fifth generation. We found no significant difference between the two treatment groups; 61.3 eggs were laid in the treatment group fed iron-coated brine shrimp and moth eggs, and 67.4 eggs were laid in the control group. The plant-free model developed in our study can reduce rearing costs by 70.5% compared to the conventional mass-rearing model. Full article
(This article belongs to the Special Issue Rearing Techniques for Biocontrol Agents of Insects, Mites, and Weeds)
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Article
Trypanosoma cruzi Parasite Load Modulates the Circadian Activity Pattern of Triatoma infestans
Insects 2022, 13(1), 76; https://doi.org/10.3390/insects13010076 - 10 Jan 2022
Cited by 1 | Viewed by 524
Abstract
American trypanosomiasis is a disease caused by the flagellate protozoan Trypanosoma cruzi, which is transmitted mainly in endemic areas by blood-sucking triatomine vectors. Triatoma infestans is the most important vector in the southern cone of South America, exhibiting a nocturnal host-seeking behavior. [...] Read more.
American trypanosomiasis is a disease caused by the flagellate protozoan Trypanosoma cruzi, which is transmitted mainly in endemic areas by blood-sucking triatomine vectors. Triatoma infestans is the most important vector in the southern cone of South America, exhibiting a nocturnal host-seeking behavior. It has been previously documented that the parasite produces changes in some triatomine species, but this is the first time that the behavior of a vector has been evaluated in relation to its parasite load. After comparing the movement events and distance traveled of infected and non-infected T. infestans, we evaluated the change produced by different T. cruzi parasite loads on its circadian locomotor activity. We observed differences between infected and non-infected triatomines, and a significant relation between the parasite load and the increase in locomotor activity of T. infestans, which was accentuated during the photophase. This could have direct implications on the transmission of T. cruzi, as the increased movement and distance traveled could enhance the contact of the vector with the host, while increasing the predation risk for the vector, which could both constitute a risk for vectorial and oral transmission to mammals. Full article
(This article belongs to the Section Insect Behavior and Pathology)
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