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Insects, Volume 13, Issue 12 (December 2022) – 102 articles

Cover Story (view full-size image): Investigations have been carried out to assess the extent of the diapause of Torymus sinensis, the biocontrol agent of the Asian chestnut gall wasp Dryocosmus kuriphilus. The seasonal variation in the galls’ toughness was measured to assess if dry galls can negatively affect emergence over time. The window of vulnerability of the galls was also evaluated in controlled conditions. The results showed that the prolonged diapause is negligible, in line with previous investigations, and thus not so decisive for the management of infestations. No difference was detected in the wall toughness of galls formed during the previous year when compared to current‐year dry galls. A negative correlation was recorded when comparing the number of oviposition events by T. sinensis and the gall toughness, highlighting how fresh galls formed in spring offer few physical barriers in relation to toughness. View this paper
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14 pages, 1942 KiB  
Article
Wheat-Bran-Based Artificial Diet for Mass Culturing of the Fall Armyworm, Spodoptera frugiperda Smith (Lepidoptera: Noctuidae)
by Shishuai Ge, Bo Chu, Wei He, Shan Jiang, Chunyang Lv, Lingyun Gao, Xiaoting Sun, Xianming Yang and Kongming Wu
Insects 2022, 13(12), 1177; https://doi.org/10.3390/insects13121177 - 19 Dec 2022
Cited by 3 | Viewed by 2508
Abstract
Spodoptera frugiperda Smith (fall armyworm (FAW)) has invaded many countries in Africa and Asia in recent years, considerably restricting global agricultural production. In this study, we assessed the rearing performance of four artificial diets (D1: an artificial FAW diet based on [...] Read more.
Spodoptera frugiperda Smith (fall armyworm (FAW)) has invaded many countries in Africa and Asia in recent years, considerably restricting global agricultural production. In this study, we assessed the rearing performance of four artificial diets (D1: an artificial FAW diet based on wheat bran and soybean, maize, and yeast powders; D2: an artificial diet developed for Helicoverpa armigera (Hübner), based on wheat bran and soybean and yeast powders; D3: an artificial diet based on soybean powder; D4: an artificial diet based on wheat bran) for FAWs. We designed D4 based on a traditional diet (D2) but substituted the wheat bran for soybean and yeast powders. At 25 ± 1 °C, 75% ± 5% RH, and a 16:8 h L:D photoperiod, the larval stage of FAWs fed on D4 lasted 15.88 d, the pupal stage lasted 9.48 d, the pupal mass was 270.45 mg, the number of eggs deposited was 1364.78, and the mating rate was 89.53%. Most biological indicators of the larvae that were fed D4 were basically consistent with those of the larvae fed on the traditional diet (D2), but the intrinsic rate of increase (r), finite rate of increase (λ), and net reproduction rate (R0) of the D4 FAWs were lower than those of the D2 FAWs. The flight capacity (flight distance, duration, and velocity were 19.73 km, 6.91 h, and 2.90 km/h, respectively) of the D4 FAWs was comparable to that of the FAWs fed a traditional diet and maize leaves. Compared with the three other formulas, the cost of using D4 was lower by 26.42% on average. These results show that using cheap wheat bran instead of soybean flour and yeast powder as the basic material for an artificial diet for FAWs is feasible, which will substantially reduce rearing costs and promote the development of new controlling measures for FAWs. In addition, this study also has a reference value for reducing the cost of artificial diets for other insects. Full article
(This article belongs to the Special Issue Recent Advances in Fall Armyworm Research)
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32 pages, 13296 KiB  
Article
Review on the Genus Stylophoronychus (Acari: Tetranychidae), with Description of a New Species
by Xiaojuan Pan, Ronald Ochoa, Daochao Jin and Tianci Yi
Insects 2022, 13(12), 1176; https://doi.org/10.3390/insects13121176 - 19 Dec 2022
Viewed by 1323
Abstract
Only two species of the genus Stylophoronychus, S. baghensis (Prasad, 1975) and S. guangzhouensis (Ma and Yuan, 1980), have been recorded in China. Herein we describe a new species Stylophoronychus wangaePan, Jin & Yi sp. nov. based on characteristics of [...] Read more.
Only two species of the genus Stylophoronychus, S. baghensis (Prasad, 1975) and S. guangzhouensis (Ma and Yuan, 1980), have been recorded in China. Herein we describe a new species Stylophoronychus wangaePan, Jin & Yi sp. nov. based on characteristics of the deutonymphs and adults. The synonym of S. guangzhouensis (Ma and Yuan, 1980) and S. lalli (Prasad, 1975) with S. vannus (Rimando, 1968) is proposed. A redescription of S. vannus (Rimando, 1968) based on the adults of both sexes, deutonymphs and a protonymph is given. The ontogenetic changes of leg chaetotaxy in two species are given and discussed. The updated key to the species of Stylophoronychus of the world is provided. Full article
(This article belongs to the Special Issue Mite Nature: Taxonomy, Behavior and Dispersion)
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13 pages, 2761 KiB  
Article
Use of a Sprayable Sex Pheromone Formulation in Landscape-Level Control of Choristoneura fumiferana Populations
by Lucas E. Roscoe, Wayne MacKinnon, Jacques Régnière, Glen Forbes, Matt Brophy and Rosanna Lamb
Insects 2022, 13(12), 1175; https://doi.org/10.3390/insects13121175 - 17 Dec 2022
Cited by 3 | Viewed by 1441
Abstract
Choristoneura fumiferana (SBW) is a major defoliating pest of balsam fir and spruce in eastern North America. As part of an integrated management strategy for SBW, we evaluated the effectiveness of mating disruption as a landscape-level population control tactic. Using a sprayable formulation [...] Read more.
Choristoneura fumiferana (SBW) is a major defoliating pest of balsam fir and spruce in eastern North America. As part of an integrated management strategy for SBW, we evaluated the effectiveness of mating disruption as a landscape-level population control tactic. Using a sprayable formulation (CONFOUNDSBW) containing a synthetic sex pheromone blend, we treated five 300 ha blocks in Northern New Brunswick with an aerially applied microencapsulated mixture. There were significant reductions in adult trap catches in treated blocks compared to untreated control blocks. Branch sampling in treated blocks showed uniform distribution of CONFOUNDSBW deposition throughout the blocks. Population densities following treatment were not significantly affected when compared to densities in control blocks, or prior to treatment. Analysis of egg:adult ratios indicates that no immigration events occurred within treatment or control blocks. The lack of population reduction following treatment strongly suggests that widespread application of CONFOUNDSBW at a rate of 50 g of active ingredient per hectare is not an effective tool in controlling SBW populations. Full article
(This article belongs to the Special Issue Chemical Communication in Insects: New Advances in IPM Strategies)
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8 pages, 881 KiB  
Article
Genetic Structure of Apis cerana Populations from South Korea, Vietnam and the Russian Far East Based on Microsatellite and Mitochondrial DNA Polymorphism
by Milyausha Kaskinova, Luisa Gaifullina, Rustem Ilyasov, Arkady Lelej, Hyung Wook Kwon, Pham Hong Thai and Elena Saltykova
Insects 2022, 13(12), 1174; https://doi.org/10.3390/insects13121174 - 17 Dec 2022
Cited by 1 | Viewed by 1402
Abstract
In this article, we present the results of the genetic analysis of Apis cerana samples from the Russian Far East, South Korea and Vietnam. An analysis of the polymorphism of seven microsatellite loci and an assessment of the haplotype diversity of the mtDNA [...] Read more.
In this article, we present the results of the genetic analysis of Apis cerana samples from the Russian Far East, South Korea and Vietnam. An analysis of the polymorphism of seven microsatellite loci and an assessment of the haplotype diversity of the mtDNA tRNAleu-COII locus were performed. A fragment of about 431 bp in tRNAleu-COII was sequenced. The analysis showed the presence of 14 haplotypes, while the predominant haplotype was Japan1. Microsatellite data revealed two differentiated clusters. The first cluster contained tropical climate A. cerana samples from Vietnam, and the second cluster combined temperate climate A. cerana samples from the Russian Far East and South Korea. Full article
(This article belongs to the Topic Advanced in Honey Bee and Apitherapy)
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14 pages, 1488 KiB  
Article
Transcriptomic Analyses Suggest the Adaptation of Bumblebees to High Altitudes
by Chengbo Liang, Daoxin Liu, Pengfei Song, Yuantao Zhou, Hongyan Yu, Guo Sun, Xiaoxuan Ma and Jingyan Yan
Insects 2022, 13(12), 1173; https://doi.org/10.3390/insects13121173 - 17 Dec 2022
Viewed by 1306
Abstract
Determining the adaptive mechanisms by which bumblebees adapt to high altitudes can help us to better understand their distribution, providing a basis for the future protection and utilization of bumblebee resources. For this study, the adaptive mechanisms of two dominant bumblebee species in [...] Read more.
Determining the adaptive mechanisms by which bumblebees adapt to high altitudes can help us to better understand their distribution, providing a basis for the future protection and utilization of bumblebee resources. For this study, the adaptive mechanisms of two dominant bumblebee species in the northeastern Qinghai-Tibet Plateau—Bombus kashmirensis and B. waltoni—were studied through transcriptomics methods. For each species, enrichment analysis of the differentially expressed genes and gene set enrichment analysis were carried out between samples collected at different altitudes (4000 m, 4500 m, and 5000 m). The results indicate that these bumblebees tend to up-regulate energy metabolism-related genes when facing extremely high-altitude environments. Of the enriched pathways up-regulated in higher altitudes, the pentose and glucuronate interconversions pathway presented the most severe up-regulation in multiple comparisons of different altitudes for B. kashmirensis, as well as the AMPK signaling pathway, which was found to be up-regulated in both species. Notably, limited by the extreme hypoxic conditions in this study, oxidative phosphorylation was found to be down-regulated with increasing altitude, which is uncommon in studies on bumblebee adaptation to high altitudes. Full article
(This article belongs to the Special Issue Insect Genome and Transcriptome Data)
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15 pages, 1237 KiB  
Article
Reference Genome Sequences of the Oriental Armyworm, Mythimna separata (Lepidoptera: Noctuidae)
by Kakeru Yokoi, Seiichi Furukawa, Rui Zhou, Akiya Jouraku and Hidemasa Bono
Insects 2022, 13(12), 1172; https://doi.org/10.3390/insects13121172 - 17 Dec 2022
Cited by 2 | Viewed by 2148
Abstract
Lepidopteran insects are an important group of animals, including those used as biochemical and physiological model species in the insect and silk industries as well as others that are major agricultural pests. Therefore, the genome sequences of several lepidopteran insects have been reported. [...] Read more.
Lepidopteran insects are an important group of animals, including those used as biochemical and physiological model species in the insect and silk industries as well as others that are major agricultural pests. Therefore, the genome sequences of several lepidopteran insects have been reported. The oriental armyworm, Mythimna separata, is an agricultural pest commonly used to study insect immune reactions and interactions with parasitoid wasps as hosts. To improve our understanding of these research topics, reference genome sequences were constructed in the present study. Using long-read and short-read sequence data, de novo assembly and polishing were performed and haplotigs were purged. Subsequently, gene predictions and functional annotations were performed. To search for orthologs of the Toll and Immune Deficiency (IMD) pathways and for C-type lectins, annotation data analysis, BLASTp, and Hummer scans were performed. The M. separata genome is 682 Mbp; its contig N50 was 2.7 Mbp, with 21,970 genes and 24,452 coding sites predicted. All orthologs of the core components of the Toll and IMD pathways and 105 C-type lectins were identified. These results suggest that the genome data were of sufficient quality for use as reference genome data and could contribute to promoting M. separata and lepidopteran research at the molecular and genome levels. Full article
(This article belongs to the Special Issue Insect Genome and Transcriptome Data)
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18 pages, 2629 KiB  
Article
Unexpected High Species Diversity of Mesolycus Gorham (Coleoptera, Lycidae) from China, with a Preliminary Investigation on Its Phylogenetic Position Based on Multiple Genes
by Haoyu Liu, Ruolan Du, Ya Kang, Xueying Ge, Xingke Yang and Yuxia Yang
Insects 2022, 13(12), 1171; https://doi.org/10.3390/insects13121171 - 17 Dec 2022
Cited by 1 | Viewed by 1139
Abstract
The lycid genus Mesolycus Gorham, 1883 is mainly distributed in East Palaearctic and Indochinese regions, but poorly studied in China; moreover, its phylogenetic placement remains controversial but has never been rigorously tested. In this study, Mesolycus was reviewed and its placement within Lycidae [...] Read more.
The lycid genus Mesolycus Gorham, 1883 is mainly distributed in East Palaearctic and Indochinese regions, but poorly studied in China; moreover, its phylogenetic placement remains controversial but has never been rigorously tested. In this study, Mesolycus was reviewed and its placement within Lycidae was tested based on a multilocus phylogeny (cox1, nad5, cox2 and Lrna) by both ML and BI analyses. The reconstructed phylogenies show that Mesolycus is a consistently recovered sister to Dilophotes Waterhouse, 1879, and they form a monophyletic clade which is well supported. This suggests that Mesolycus definitely belongs to Dilophotini rather than to Macrolycini of Lycinae. Besides, three species originally described or placed in Dilophotes are transferred to Mesolycus, including M. atricollis (Pic, 1926) comb. n., M. particularis (Pic, 1928) comb. n. and M. pacholatkoi (Bic, 2002) comb. n. Four new species are discovered in China, including M. shaanxiensis sp. n., M. dentatus sp. n., M. breviplatus sp. n. and M. varus sp. n. Two species, M. murzini Kazantsev, 2004 and M. rubromarginatus Kazantsev, 2013, are recorded from China for the first time. A key for the identification of all Mesolycus species is provided. China was revealed as the region with the highest species diversity of this genus. Full article
(This article belongs to the Section Insect Systematics, Phylogeny and Evolution)
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22 pages, 2625 KiB  
Article
A Non-Gradual Development Process of Cicada Eyes at the End of the Fifth-Instar Nymphal Stage to Obtain Visual Ability
by Minjing Su, Feimin Yuan, Tiantian Li and Cong Wei
Insects 2022, 13(12), 1170; https://doi.org/10.3390/insects13121170 - 16 Dec 2022
Viewed by 1574
Abstract
Insects’ visual system is directly related to ecology and critical for their survival. Some cicadas present obvious differences in color and ultrastructure of compound eyes between nymphal and adult stages, but little is known about when cicadas obtain their visual ability to deal [...] Read more.
Insects’ visual system is directly related to ecology and critical for their survival. Some cicadas present obvious differences in color and ultrastructure of compound eyes between nymphal and adult stages, but little is known about when cicadas obtain their visual ability to deal with the novel above-ground habitat. We use transcriptome analyses and reveal that cicada Meimuna mongolica has a trichromatic color vision system and that the eyes undergo a non-gradual development process at the end of the 5th-instar nymphal stage. The white-eye 5th-instar nymphs (i.e., younger 5th-instar nymphs) have no visual ability because critical components of the visual system are deficient. The transformation of eyes toward possessing visual function takes place after a tipping point in the transition phase from the white-eye period to the subsequent red-eye period, which is related to a decrease of Juvenile Hormone. The period shortly after adult emergence is also critical for eye development. Key differentially-expressed genes related to phototransduction and chromophore synthesis play positive roles for cicadas to adapt to above-ground habitat. The accumulation of ommochromes corresponds to the color change of eyes from white to red and dark brown during the end of the 5th-instar nymphal period. Cuticle tanning leads to eye color changing from dark-brown to light-brown during the early adult stage. We hypothesize that the accumulation of ommochromes occurring at the end of 5th-instar nymphal stage and the early adult stage is not only for cicadas to obtain visual ability, but also is a secure strategy to cope with potential photodamage after emergence. Full article
(This article belongs to the Section Insect Physiology, Reproduction and Development)
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20 pages, 4394 KiB  
Article
In Silico and In Vivo Evaluation of Synthesized SCP-2 Inhibiting Compounds on Life Table Parameters of Helicoverpa armigera (Hübner)
by Qamar Saeed, Faheem Ahmad, Numan Yousaf, Haider Ali, Syed Azhar Ali Shah Tirmazi, Abdulrahman Alshammari, Naeema Kausar, Mahmood Ahmed, Muhammad Imran, Muhammad Jamshed, Metab Alharbi and Muhammad Muddassar
Insects 2022, 13(12), 1169; https://doi.org/10.3390/insects13121169 - 16 Dec 2022
Viewed by 1619
Abstract
For environment-friendly, safe and nonpersistent chemical control of a significant polyphagous insect pest, Helicoverpa armigera, discovery of growth-regulating xenobiotics can offer a sustainable alternative to conventional insecticides. For this purpose, chemically synthesized compounds to inhibit sterol carrier protein (SCP-2) function using in [...] Read more.
For environment-friendly, safe and nonpersistent chemical control of a significant polyphagous insect pest, Helicoverpa armigera, discovery of growth-regulating xenobiotics can offer a sustainable alternative to conventional insecticides. For this purpose, chemically synthesized compounds to inhibit sterol carrier protein (SCP-2) function using in silico and in vivo assays were evaluated to estimate their impact on the survivals and lifetable indices of H. armigera. From nine chemically synthesized compounds, OA-02, OA-06 and OA-09 were selected for this study based on binding poses mimicking cholesterol, a natural substrate of sterol carrier protein and molecular dynamics simulations. In vivo bioassays revealed that all compounds significantly reduced the larval and pupal weight accumulations and stadia lengths. Subsequently, the pupal periods were prolonged upon treatment with higher doses of the selected compounds. Moreover, OA-09 significantly reduced pupation and adult emergence rates as well as the fertility of female moths; however, fecundity remained unaffected, in general. The life table parameters of H. armigera were significantly reduced when treated with OA-09 at higher doses. The population treated with 450 μM of OA-09 had the least net reproductive rates (Ro) and gross reproductive rate (GRR) compared to the control population. The same compound resulted in a declining survival during the early stages of development coupled with reduced larval and pupal durations, and fertility. These results have a significant implication for developing an effective and sustainable chemical treatment against H. armigera infestation. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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12 pages, 921 KiB  
Article
Expression of Immunity- and Stress-Related Genes during an Intermolt Period in the Colorado Potato Beetle
by Vadim Yu. Kryukov, Ulyana N. Rotskaya, Olga N. Yaroslavtseva, Yury A. Noskov and Viktor V. Glupov
Insects 2022, 13(12), 1168; https://doi.org/10.3390/insects13121168 - 16 Dec 2022
Cited by 2 | Viewed by 1559
Abstract
Different developmental stages of insects may be dissimilar in immunity functioning. Additionally, the stages often inhabit diverse environments with specific microbial communities. In the Colorado potato beetle, a strong increase in resistance to entomopathogenic fungi is observed during the intermolt period of last-instar [...] Read more.
Different developmental stages of insects may be dissimilar in immunity functioning. Additionally, the stages often inhabit diverse environments with specific microbial communities. In the Colorado potato beetle, a strong increase in resistance to entomopathogenic fungi is observed during the intermolt period of last-instar larvae, but mechanisms of this change are insufficiently understood. We studied changes in the expression of immunity- and stress-related genes in the fat body and integument during this intermolt period by quantitative PCR. By the end of the instar, there was upregulation of transcription factors of Toll, IMD, and Jak–Stat pathways as well as genes encoding metalloprotease inhibitors, odorant-binding proteins, and heat shock proteins. Nonetheless, the expression of gene LdRBLk encoding β-lectin did not change during this period. Most of the aforementioned genes were upregulated in response to Metarhizium robertsii topical infection. The expression alterations were more pronounced in recently molted larvae than in finishing feeding larvae and in the integument compared to the fat body. We believe that upregulation of immune-system- and stress-related genes at the end of the intermolt period is an adaptation caused by migration of larvae into soil, where the probability of encountering entomopathogenic fungi is high. Full article
(This article belongs to the Special Issue Insect Hormones, Metabolism, Immunity and Development)
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14 pages, 2545 KiB  
Article
Apilactobacillus kunkeei Alleviated Toxicity of Acetamiprid in Honeybee
by Peng Liu, Jingheng Niu, Yejia Zhu, Zhuang Li, Liang Ye, Haiqun Cao, Tengfei Shi and Linsheng Yu
Insects 2022, 13(12), 1167; https://doi.org/10.3390/insects13121167 - 16 Dec 2022
Viewed by 1310
Abstract
Nowadays, colony collapse disorder extensively affects honeybees. Insecticides, including acetamiprid, are considered as critical factors. As prevalent probiotics, we speculated that supplementation with lactic acid bacteria (LAB) could alleviate acetamiprid-induced health injuries in honeybees. Apilactobacillus kunkeei was isolated from beebread; it significantly increased [...] Read more.
Nowadays, colony collapse disorder extensively affects honeybees. Insecticides, including acetamiprid, are considered as critical factors. As prevalent probiotics, we speculated that supplementation with lactic acid bacteria (LAB) could alleviate acetamiprid-induced health injuries in honeybees. Apilactobacillus kunkeei was isolated from beebread; it significantly increased the survival of honeybees under acetamiprid exportation (from 84% to 92%). Based on 16S rRNA pyrosequencing, information on the intestinal bacteria of honeybees was acquired. The results showed that supplementation with A. kunkeei significantly increased survival and decreased pollen consumption by honeybees under acetamiprid exportation. Under acetamiprid exportation, some opportunistic and pathogenic bacteria invaded the intestinal regions. Subsequently, the community richness and diversity of symbiotic microbiota were decreased. The community structure of intestinal bacteria was changed and differentiated. However, with the supplementation of A. kunkeei, the community richness and community diversity of symbiotic microbiota showed an upward trend, and the community structure was stabilized. Our results showed that A. kunkeei alleviated acetamiprid-induced symbiotic microbiota dysregulation and mortality in honeybees. This demonstrates the importance of symbiotic microbiota in honeybees and supports the application of Apilactobacillus kunkeei as probiotics in beekeeping. Full article
(This article belongs to the Section Insect Societies and Sociality)
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16 pages, 2483 KiB  
Article
Behavior and Bioadhesives: How Bolas Spiders, Mastophora hutchinsoni, Catch Moths
by Candido Diaz, Jr. and John H. Long, Jr.
Insects 2022, 13(12), 1166; https://doi.org/10.3390/insects13121166 - 16 Dec 2022
Cited by 2 | Viewed by 2119
Abstract
Spiders use various combinations of silks, adhesives, and behaviors to ensnare and trap prey. A common but difficult to catch prey in most spider habitats are moths. They easily escape typical orb-webs because their bodies are covered in sacrificial scales that flake off [...] Read more.
Spiders use various combinations of silks, adhesives, and behaviors to ensnare and trap prey. A common but difficult to catch prey in most spider habitats are moths. They easily escape typical orb-webs because their bodies are covered in sacrificial scales that flake off when in contact with the web’s adhesives. This defense is defeated by spiders of the sub-family of Cyrtarachninae, moth-catching specialists who combine changes in orb-web structure, predatory behavior, and chemistry of the aggregate glue placed in those webs. The most extreme changes in web structure are shown by bolas spiders, who create a solitary capture strand containing only one or two glue droplets at the end of a single thread. They prey on male moths by releasing pheromones to draw them within range of their bolas, which they flick to ensnare the moth. We used a high-speed video camera to capture the behavior of the bolas spider Mastophora hutchinsoni. We calculated the kinematics of spiders and moths in the wild to model the physical and mechanical properties of the bolas during prey capture, the behavior of the moth, and how these factors lead to successful prey capture. We created a numerical model to explain the mechanical behavior of the bolas silk during prey capture. Our kinematic analysis shows that the material properties of the aggregate glue bolas of M. hutchinsoni are distinct from that of the other previously analyzed moth-specialist, Cyrtarachne akirai. The spring-like behavior of the M. hutchinsoni bolas suggests it spins a thicker liquid. Full article
(This article belongs to the Special Issue Spider Ecology and Behaviour)
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20 pages, 3244 KiB  
Article
Marked Effects of Larval Salt Exposure on the Life History and Gut Microbiota of the Malaria Vector Anopheles merus (Diptera: Culicidae)
by Ashmika Singh, Nashrin F. Patel, Mushal Allam, Wai-Yin Chan, Thabo Mohale, Arshad Ismail and Shüné V. Oliver
Insects 2022, 13(12), 1165; https://doi.org/10.3390/insects13121165 - 16 Dec 2022
Viewed by 1859
Abstract
Anopheles merus can breed in a range of saltwater concentrations. The consequences of this ability on the life history of adult An. merus are poorly understood. This study examined the effects of exposure to 0, 2.1875, 4.375, 8.75, and 17.5 g/L of sodium [...] Read more.
Anopheles merus can breed in a range of saltwater concentrations. The consequences of this ability on the life history of adult An. merus are poorly understood. This study examined the effects of exposure to 0, 2.1875, 4.375, 8.75, and 17.5 g/L of sodium chloride on An. merus. The effects on larval development, adult longevity, fertility, and fecundity, as well as deltamethrin tolerance were examined. The effect of larval salt exposure on the expression of defensin-1 in adults was examined by quantitative Real-Time PCR. Finally, the effect of the larval salt concentration on microbial dynamics was assessed by 16S Next Generation Sequencing. High concentrations of saltwater increased larval development time and number of eggs laid, as well as deltamethrin tolerance. Larval exposure to salt also reduced the expression of defensin-1. The exposure also had a significant effect on microbial diversity in larvae and adults. The diversity of larvae decreased once adults emerged. Salt-tolerant bacterial genera predominated in larvae but were absent in adults. High salt concentrations resulted in greater abundance of Plasmodium-protective genera in adults. Although this study was conducted on a laboratory strain of An. merus, these data suggest that osmoregulation has a significant effect on the life history of the species with potential epidemiological consequences. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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11 pages, 5749 KiB  
Article
Comparative Analysis of Mitogenomes of Chironomus (Diptera: Chironomidae)
by Shu-Yi Li, Yan-Min Zhao, Bing-Xin Guo, Chen-Hong Li, Bing-Jiao Sun and Xiao-Long Lin
Insects 2022, 13(12), 1164; https://doi.org/10.3390/insects13121164 - 16 Dec 2022
Cited by 5 | Viewed by 1482
Abstract
(1) Background: Chironomids are biological indicators, playing an important role in monitoring and assessing the changes in water ecosystems. Mitochondrial genomes have been widely applied as a molecular marker to analyze the taxonomy and phylogeny of insects. However, knowledge of the mitogenomes of [...] Read more.
(1) Background: Chironomids are biological indicators, playing an important role in monitoring and assessing the changes in water ecosystems. Mitochondrial genomes have been widely applied as a molecular marker to analyze the taxonomy and phylogeny of insects. However, knowledge of the mitogenomes of Chironomus species is scarce at present, which limits our understanding of the evolutionary relationships among Chironomus. (2) Methods: In our study, the mitogenomes and their basic structure of 12 Chironomus species and one Microchironomus species were newly sequenced. Combined with reported mitogenomes, a total of 15 mitogenomes of Chironomus were selected for a comparative mitogenomic analysis and phylogenetic reconstruction of Chironomus. (3) Results: Each mitogenome of the Chironomus species has the typical 37 genes and a control region. The basic structure of the whole mitogenomes of Chironomus species is relatively conservative, and the genetic arrangements stay the same as the ancestral mitogenome. (4) Conclusions: Our study enriches the library of mitogenomes of chironomids and provides a valuable resource for understanding the evolutionary history of Chironomus. Full article
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12 pages, 1894 KiB  
Article
Comparative Silk Transcriptomics Illuminates Distinctive Impact of Artificial Selection in Silkworm Modern Breeding
by Kesen Zhu, Yanfei Chen, Lei Chen and Hui Xiang
Insects 2022, 13(12), 1163; https://doi.org/10.3390/insects13121163 - 16 Dec 2022
Cited by 2 | Viewed by 1195
Abstract
Early domestication and the following improvement are two important processes in the cocoon silk evolution of silkworms. In contrast to early domestication, understanding of the improvement process is still fuzzy. By systematically comparing the larval silk gland transcriptomes of the wild, early domestic, [...] Read more.
Early domestication and the following improvement are two important processes in the cocoon silk evolution of silkworms. In contrast to early domestication, understanding of the improvement process is still fuzzy. By systematically comparing the larval silk gland transcriptomes of the wild, early domestic, and improved silkworms, we highlighted a novel landscape of transcriptome in the silk glands of improved ones. We first clarified that silk cocoon protein genes were up-regulated in modern breeding but not in early domestication. Furthermore, we found that differentially expressed genes (DEGs) between improved and early domestic silkworms (2711), as well as between improved and wild silkworms (2264), were obviously more than those between the early domestic and wild silkworms (158), with 1671 DEGs specific in the improved silkworm (IS-DEGs). Hierarchical clustering of all the DEGs consistently indicated that improved silkworms were significantly diverged from the early domestic and wild silkworms, suggesting that modern breeding might cause prompt and drastic dynamic changes of gene expression in the silk gland. We further paid attention to these 1671 IS-DEGs and were surprised to find that down-regulated genes were enriched in basic organonitrogen compound biosynthesis, RNA biosynthesis, and ribosome biogenesis processes, which are generally universally expressed, whereas those up-regulated genes were enriched in organonitrogen compound catabolic processes and functions involving in the dynamic regulation of protein post-translation of modification. We finally highlighted one candidate improvement gene among these up-regulated IS-DEGs, i.e., GDAP2, which may play roles in silk behavior and the overall robustness of the improved silkworm. The findings strongly suggest that modern breeding may facilitate effective control of the basic consumption of nitrogen and a stronger switch of nitrogen resources from other tissues to the silk glands, for an efficient supply for silk production, and implies the importance of brain behavior and robustness in silk yield improvement of modern breeding. Full article
(This article belongs to the Section Insect Systematics, Phylogeny and Evolution)
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14 pages, 825 KiB  
Article
Evaluation of Phosphine Resistance in Populations of Sitophilus oryzae, Oryzaephilus surinamensis and Rhyzopertha dominica in the Czech Republic
by Radek Aulicky, Vaclav Stejskal, Barbora Frydova and Christos Athanassiou
Insects 2022, 13(12), 1162; https://doi.org/10.3390/insects13121162 - 16 Dec 2022
Cited by 3 | Viewed by 1620
Abstract
Phosphine is globally the most widely adopted fumigant for the control of storage pests. Recently, an increase in the frequency of stored-product pest resistance has been observed with significant geographical and interspecific variations. In this context, there are available data for the occurrence [...] Read more.
Phosphine is globally the most widely adopted fumigant for the control of storage pests. Recently, an increase in the frequency of stored-product pest resistance has been observed with significant geographical and interspecific variations. In this context, there are available data for the occurrence of resistant populations from America, Asia, Africa, and Australia, but there are few data in the case of Europe. Therefore, the aim of this work was to evaluate phosphine efficacy in important beetle pests of stored products, i.e., Sitophilus oryzae (L.), Oryzaephilus surinamensis (L.), and Rhyzopertha dominica (F.) sampled from the Czech Republic, using a rapid diagnostic test that is based on the speed to knockdown after exposure. Apart from the standard laboratory populations, which were used as the controls, we tested 56 field populations of these three species, collected in Czech farm grain stores. The survey revealed that 57.1% of the tested field populations were classified as phosphine-susceptible, based on the knockdown method used. However, profound variations among species and populations were recorded. The species with the highest percentage of resistant populations was R. dominica (71.4% of the populations; resistance coefficient 0.5–4.1), followed by S. oryzae (57.1% of the populations; resistance coefficient 0.8–6.9), and O. surinamensis (9.5% of the populations; resistance coefficient 0.5–2.9). Regarding the intra-population variability in response to phosphine (slope of the knockdown time regression), the laboratory and slightly resistant populations of all species were homogenous, whereas the most resistant populations were strongly heterogeneous. Our data show that the occurrence of resistance in the Czech Republic is relatively widespread and covers a wide range of species, necessitating the need for the adoption of an action plan for resistance mitigation. Full article
(This article belongs to the Collection Integrated Management and Impact of Stored-Product Pests)
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25 pages, 145307 KiB  
Article
Comparative Studies of Perianal Structures in Myrmecophilous Aphids (Hemiptera, Aphididae)
by Natalia Kaszyca-Taszakowska, Mariusz Kanturski and Łukasz Depa
Insects 2022, 13(12), 1160; https://doi.org/10.3390/insects13121160 - 16 Dec 2022
Cited by 3 | Viewed by 1572
Abstract
There are three types of relationships between aphids and ants: non-myrmecophilous, obligatory and facultatively myrmecophilous. The degree of involvement in this mutualism is believed to be corelated with morphological adaptations of perianal structures. In this manuscript, we analyzed the differences of these structures [...] Read more.
There are three types of relationships between aphids and ants: non-myrmecophilous, obligatory and facultatively myrmecophilous. The degree of involvement in this mutualism is believed to be corelated with morphological adaptations of perianal structures. In this manuscript, we analyzed the differences of these structures in obligatorily (18 species) and facultatively (10 species) myrmecophilous aphids. Scanning electron microscopy (SEM) and light stereoscopic microscopy (LSM) techniques were used for these studies. Comparison of structures showed no strict relationship between their morphology and the degree myrmecophily, with certain indication that the microsculpture of perianal cuticle may play role in protection of aphids against honeydew droplet in facultatively myrmecophilous aphids. Full article
(This article belongs to the Collection Hemiptera: Ecology, Physiology, and Economic Importance)
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16 pages, 2555 KiB  
Article
Rickettsia Infection Benefits Its Whitefly Hosts by Manipulating Their Nutrition and Defense
by Ze-Yun Fan, Yuan Liu, Zi-Qi He, Qin Wen, Xin-Yi Chen, Muhammad Musa Khan, Mohamed Osman, Nasser Said Mandour and Bao-Li Qiu
Insects 2022, 13(12), 1161; https://doi.org/10.3390/insects13121161 - 15 Dec 2022
Cited by 4 | Viewed by 2038
Abstract
Endosymbionts play an essential role in the biology, physiology and immunity of insects. Many insects, including the whitefly Bemisia tabaci, are infected with the facultative endosymbiont Rickettsia. However, the mutualism between Rickettsia and its whitefly host remains unclear. This study investigated the [...] Read more.
Endosymbionts play an essential role in the biology, physiology and immunity of insects. Many insects, including the whitefly Bemisia tabaci, are infected with the facultative endosymbiont Rickettsia. However, the mutualism between Rickettsia and its whitefly host remains unclear. This study investigated the biological and physiological benefits of Rickettsia infection to B. tabaci. Results revealed that infection of Rickettsia increased the fertility, the survival rate from nymph to adult and the number of female whiteflies. In addition, this facilitation caused a significant reduction in nymphal developmental duration but did not affect percentage rate of egg hatching. Rickettsia infected B. tabaci had significantly higher glycogen, soluble sugar and trehalose contents than Rickettsia negative B. tabaci individuals. Rickettsia also improved the immunity of its whitefly hosts. Rickettsia infested B. tabaci had lower mortality rates and higher semi-lethal concentrations (LC50) when exposed to the fungus Akanthomyces attenuatus and the insecticides imidacloprid and spirotetramat. The percentage of parasitism by Encarsia formosa was also reduced by Rickettsia infection. Overall, Rickettsia infection benefits B. tabaci by improving the nutritional composition of its host, and also protects B. tabaci by enhancing its resistance towards insecticides (imidacloprid and spirotetramat), entomopathogenic fungi (A. attenuatus) and its main parasitoid (E. formosa); all of which could significantly impact on current management strategies. Full article
(This article belongs to the Special Issue Insect Vectors of Plant Diseases)
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14 pages, 1221 KiB  
Article
On the Origin of Neo-Sex Chromosomes in the Neotropical Dragonflies Rhionaeschna bonariensis and R. planaltica (Aeshnidae, Odonata)
by Liliana M. Mola, Iva Vrbová, Daniela S. Tosto, Magda Zrzavá and František Marec
Insects 2022, 13(12), 1159; https://doi.org/10.3390/insects13121159 - 15 Dec 2022
Viewed by 1601
Abstract
Odonata have holokinetic chromosomes. About 95% of species have an XX/X0 sex chromosome system, with heterogametic males. There are species with neo-XX/neo-XY sex chromosomes resulting from an X chromosome/autosome fusion. The genus Rhionaeschna includes 42 species found in the Americas. We analyzed the [...] Read more.
Odonata have holokinetic chromosomes. About 95% of species have an XX/X0 sex chromosome system, with heterogametic males. There are species with neo-XX/neo-XY sex chromosomes resulting from an X chromosome/autosome fusion. The genus Rhionaeschna includes 42 species found in the Americas. We analyzed the distribution of the nucleolar organizer region (NOR) using FISH with rDNA probes in Rhionaeschna bonariensis (n = 12 + neo-XY), R. planaltica (n = 7 + neo-XY), and Aeshna cyanea (n = 13 + X0). In R. bonariensis and A. cyanea, the NOR is located on a large pair of autosomes, which have a secondary constriction in the latter species. In R. planaltica, the NOR is located on the ancestral part of the neo-X chromosome. Meiotic analysis and FISH results in R. planaltica led to the conclusion that the neo-XY system arose by insertion of the ancestral X chromosome into an autosome. Genomic in situ hybridization, performed for the first time in Odonata, highlighted the entire neo-Y chromosome in meiosis of R. bonariensis, suggesting that it consists mainly of repetitive DNA. This feature and the terminal chiasma localization suggest an ancient origin of the neo-XY system. Our study provides new information on the origin and evolution of neo-sex chromosomes in Odonata, including new types of chromosomal rearrangements, NOR transposition, and heterochromatin accumulation. Full article
(This article belongs to the Special Issue Comparative Cytogenetics and Molecular Systematics of Insects)
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17 pages, 2273 KiB  
Article
Demographic Evaluation of the Control Potential of Orius minutus (Hemiptera: Anthocoridae) Preying on Dendrothrips minowai Priesner (Thysanoptera: Thripidae) at Different Temperatures
by Rongmeng Lan, Xiaoli Ren, Kunqian Cao, Xia Zhou and Linhong Jin
Insects 2022, 13(12), 1158; https://doi.org/10.3390/insects13121158 - 15 Dec 2022
Cited by 1 | Viewed by 1197
Abstract
Tea thrips (Dendrothrips minowai Priesner) are the main pests that seriously affect the yield and quality of tea, resulting in huge economic losses. The Orius minutus is one of the most important natural enemies or BCA of thrips. However, we are not [...] Read more.
Tea thrips (Dendrothrips minowai Priesner) are the main pests that seriously affect the yield and quality of tea, resulting in huge economic losses. The Orius minutus is one of the most important natural enemies or BCA of thrips. However, we are not concerned with its predation ability on tea thrips, nor thermal influence on this pattern and their interaction. Therefore, this study recorded life table data of O. minutus and tea thrips combined with predation rate data to assess the ability of O. minutus to control tea thrips using age-stage, two-sex life tables at five constant temperatures. The results showed that at 25 °C, O. minutus had the highest predation rate on tea thrips, with an average generation time (T) of 22 d, intrinsic rate of increase (r) of 0.12 d-1, fecundity of 64.17, net reproduction rate (R0) of 12.76 offspring, and net predation rate (c0) of 310.92. In addition, around 410,000 adults and 1.98 million eggs were produced within 120 days. While the temperature change was straightforward, temperature effects on insects are not linear. The population size of the O. minutus and tea thrip trended similarly at 15–30 °C and would eliminate dramatically at 35 °C. Meanwhile, the results indicated that O. minutus could effectively inhibit the population growth of tea thrips at 15–30 °C, within 5–19 days at an intervention ratio of 10 adult O. minutus and 200 thrips individuals. The simulations under different mediated temperatures demonstrated that O. minutus is effective against tea thrips over a wide temperature range expected to be potential for biocontrol of tea thrips in tea gardens. Full article
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8 pages, 542 KiB  
Article
A Binary Mixture of Emamectin Benzoate and Chlorantraniliprole Supplemented with an Adjuvant Effectively Controls Spodoptera frugiperda
by Junteng Zhang, Jianjun Jiang, Kan Wang, Yixi Zhang, Zewen Liu and Na Yu
Insects 2022, 13(12), 1157; https://doi.org/10.3390/insects13121157 - 15 Dec 2022
Cited by 6 | Viewed by 2301
Abstract
The fall armyworm (FAW) Spodoptera frugiperda is a notorious pest, causing severe crop damage worldwide and prompting effective prevention and control. Over-reliance on and intensive use of insecticides are prone to leading to the rapid evolution of insecticide resistance, urging rational insecticide application. [...] Read more.
The fall armyworm (FAW) Spodoptera frugiperda is a notorious pest, causing severe crop damage worldwide and prompting effective prevention and control. Over-reliance on and intensive use of insecticides are prone to leading to the rapid evolution of insecticide resistance, urging rational insecticide application. One effective way of rational insecticide application is to apply insecticides of different modes of action in combination or supplemented with adjuvants. In this study, we assessed the efficacies of two individual insecticides, emamectin benzoate (EB) and chlorantraniliprole (CT), and their mixture, supplemented with and without the oil adjuvant Jijian® to control FAW in laboratory bioassays and a field trial. Both EB and CT showed high toxicities to FAW. The EB × CT mixture at a mass ratio of 9:1 yielded a remarkable synergistic effect, with the co-toxicity coefficient (CTC) being 239.38 and the median lethal concentration (LC50) being 0.177 mg/L. In leaf-spray bioassays, the addition of the adjuvant reduced the LC50 values of both the individual insecticides and the EB × CT mixture by more than 59%, significantly improving the efficacies. The field trial confirmed the synergistic effects of the adjuvant, which reduced the amount of EB × CT mixture by 80%. This study provides an effective and promising insecticide–adjuvant mixture to control S. frugiperda. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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13 pages, 1536 KiB  
Article
Ecological Aspects of the Phlebotominae Fauna (Diptera: Psychodidae) among Forest Fragments and Built Areas in an Endemic Area of American Visceral Leishmaniasis in João Pessoa, Paraíba, Brazil
by Bruna Queiroz da Silva, Margarete Martins dos Santos Afonso, Lucas José Macêdo Freire, Antônio Luís Ferreira de Santana, Alessandre Pereira-Colavite and Elizabeth Ferreira Rangel
Insects 2022, 13(12), 1156; https://doi.org/10.3390/insects13121156 - 14 Dec 2022
Cited by 1 | Viewed by 1631
Abstract
Sand flies are dipterans of medical importance, as some species are vectors of American visceral leishmaniasis (AVL). The municipality of João Pessoa (Paraíba, northeastern Brazil), is an endemic region for AVL, having high rates of human and canine cases. The main objective was [...] Read more.
Sand flies are dipterans of medical importance, as some species are vectors of American visceral leishmaniasis (AVL). The municipality of João Pessoa (Paraíba, northeastern Brazil), is an endemic region for AVL, having high rates of human and canine cases. The main objective was to evaluate the sand fly fauna among forest fragments and built areas, and its relationship with environmental conditions. HP light traps were placed in the studied areas from March 2019 to July 2021. A total of 2141 specimens of phlebotomines were captured, comprising nine genera and ten species. Temperature and humidity were significant and positive only in built areas. The diversity composition among forest fragments and built areas was different and the AVL vector, Lutzomyia longipalpis, was the most prevalent species in built areas. The study showed that the built areas present differences in their richness and diversity of sand flies in relation to forest fragments, concluding that the conservation of forest areas, even if urban fragments, favors the diversity of phlebotomine species. Full article
(This article belongs to the Topic Arthropod Biodiversity: Ecological and Functional Aspects)
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14 pages, 2458 KiB  
Article
Comparison of Two Different Morphological Methods to Study the Pronotum of Cimicidae: Bed Bugs, Bat Bugs, and Swallow Bugs
by Dora M. Rajonhson, Chadchalerm Raksakoon, Anon Payakkapol, Sébastien Dujardin, Jean-Pierre Dujardin and Rutcharin Potiwat
Insects 2022, 13(12), 1155; https://doi.org/10.3390/insects13121155 - 14 Dec 2022
Cited by 2 | Viewed by 1975
Abstract
An infestation of a Cimicidae (Hemiptera: Cimicidae) member, especially the bed bug, can cause economic loss and impact health. A cost-effective and user-friendly method for identifying the infesting species will help with the early detection and control of infestations. A linear morphometric method [...] Read more.
An infestation of a Cimicidae (Hemiptera: Cimicidae) member, especially the bed bug, can cause economic loss and impact health. A cost-effective and user-friendly method for identifying the infesting species will help with the early detection and control of infestations. A linear morphometric method is often used, but it requires the examination of many characters and a highly preserved specimen. We conducted a comparative morphometric study of the effectiveness of Cimicidae classification using a single organ, the pronotum, through outline-based and linear morphometric methods. Bat (Stricticimex parvus), human (Cimex hemipterus), and bird (Paracimex sp.) ectoparasites were subject of the study. With both methods, the properties of size and shape were compared and used separately to classify the specimens. Classification analyses of the two methods provided similar results, but more informative variables of size and shape were obtained with the outline-based approach. Size, as analyzed with the outline-based method, could detect sexual dimorphism, and produced better reclassification. The shape variables obtained from the linear measurements were strongly influenced by size variation, much more than the ones obtained from coordinates describing the pronotum contours. Our data suggest that the outline-based approach provides better characterization variables, thus we recommend them for a wider use in other Cimicidae family members. Full article
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27 pages, 9965 KiB  
Article
Four New Species of Larval Charletonia and Leptus (Acari: Trombidiformes: Erythraeidae), with a Checklist of the Two Genera and Their Hosts from China
by Si-Yuan Xu, Tian-Ci Yi, Jian-Jun Guo and Dao-Chao Jin
Insects 2022, 13(12), 1154; https://doi.org/10.3390/insects13121154 - 14 Dec 2022
Cited by 2 | Viewed by 1251
Abstract
Four new species, Charletonia rectangia Xu and Jin sp. nov., Leptus (Leptus) bomiensis Xu and Jin sp. nov., Leptus (Leptus) longisolenidionus Xu and Jin sp. nov., and Leptus (Leptus) striatus Xu and Jin sp. [...] Read more.
Four new species, Charletonia rectangia Xu and Jin sp. nov., Leptus (Leptus) bomiensis Xu and Jin sp. nov., Leptus (Leptus) longisolenidionus Xu and Jin sp. nov., and Leptus (Leptus) striatus Xu and Jin sp. nov. are described and illustrated based on larvae. All four new species are from biodiversity hotspots, L. (L.) bomiensissp. nov. from the Eastern Himalayas biodiversity hotspot, while the other three species from the Indo–Burma biodiversity hotspot. Full article
(This article belongs to the Special Issue Mite Nature: Taxonomy, Behavior and Dispersion)
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15 pages, 3014 KiB  
Article
Attraction of Insects to Ornamental Lighting Used on Cultural Heritage Buildings: A Case Study in an Urban Area
by Anxo Méndez, Luis Martín, Justo Arines, Rafael Carballeira and Patricia Sanmartín
Insects 2022, 13(12), 1153; https://doi.org/10.3390/insects13121153 - 14 Dec 2022
Cited by 1 | Viewed by 2213
Abstract
Artificial light at night (ALAN) reduces insect populations by altering their movements, foraging, reproduction, and predation. Although ALAN is mainly associated with streetlights and road networks, the ornamental illumination of monuments is making an increasing (but not well-studied) contribution. We compared insect attraction [...] Read more.
Artificial light at night (ALAN) reduces insect populations by altering their movements, foraging, reproduction, and predation. Although ALAN is mainly associated with streetlights and road networks, the ornamental illumination of monuments is making an increasing (but not well-studied) contribution. We compared insect attraction to two different types of light sources: a metal halide lamp (a type currently used to illuminate monuments) and an environmentally sound prototype lamp (CromaLux) comprising a combination of green and amber LEDs. The experiment was performed within the pilot CromaLux project in Santiago de Compostela (NW Spain). The abundance and diversity of the insects captured between June and October 2021 in the areas surrounding both light sources and in an unlit area were compared. By limiting the light emitted to amber and green, the CromaLux lamps reduced the number and diversity of insects, morphospecies, and orders attracted to the light, with similar numbers captured as in the unilluminated area, while a greater diversity of insects was captured beside the metal halide lamp. This effect has been demonstrated for almost all insect orders trapped, especially in Diptera, Lepidoptera, Coleoptera, Hemiptera, and Hymenoptera. On the contrary, Psocoptera showed a similar attraction to the CromaLux and metal halide lamps, a phenomenon whose causes deserve further investigation. As expected, Diptera were the most diverse and abundant insects in all samples, but the abundance of Lepidoptera was unexpectedly low (4%), which is in line with the worldwide evidence of the progressive decline of populations of this group. The study findings provide evidence that selecting specific wavelengths for ornamental lighting reduces the attraction of insects while maintaining adequate illumination of monuments for aesthetic purposes, resulting in a lower environmental impact on nocturnal insects. This study provides reference data for developing principles of good practices leading to possible regulatory and legal solutions and the incorporation of specific measures for artificial lighting of monuments and urban structures. Full article
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16 pages, 1658 KiB  
Article
Insect Feeding on Sorghum bicolor Pollen and Hymenoptera Attraction to Aphid-Produced Honeydew
by Karen R. Harris-Shultz, John Scott Armstrong, Michael Caballero, William Wyatt Hoback and Joseph E. Knoll
Insects 2022, 13(12), 1152; https://doi.org/10.3390/insects13121152 - 14 Dec 2022
Viewed by 2474
Abstract
Pollinators are declining globally, potentially reducing both human food supply and plant diversity. To support pollinator populations, planting of nectar-rich plants with different flowering seasons is encouraged while promoting wind-pollinated plants, including grasses, is rarely recommended. However, many bees and other pollinators collect [...] Read more.
Pollinators are declining globally, potentially reducing both human food supply and plant diversity. To support pollinator populations, planting of nectar-rich plants with different flowering seasons is encouraged while promoting wind-pollinated plants, including grasses, is rarely recommended. However, many bees and other pollinators collect pollen from grasses which is used as a protein source. In addition to pollen, Hymenoptera may also collect honeydew from plants infested with aphids. In this study, insects consuming or collecting pollen from sweet sorghum, Sorghum bicolor, were recorded while pan traps and yellow sticky card surveys were placed in grain sorghum fields and in areas with Johnsongrass, Sorghum halepense to assess the Hymenoptera response to honeydew excreted by the sorghum aphid (SA), Melanaphis sorghi. Five genera of insects, including bees, hoverflies, and earwigs, were observed feeding on pollen in sweet sorghum, with differences observed by date, but not plant height or panicle length. Nearly 2000 Hymenoptera belonging to 29 families were collected from grain sorghum with 84% associated with aphid infestations. About 4 times as many Hymenoptera were collected in SA infested sorghum with significantly more ants, halictid bees, scelionid, sphecid, encyrtid, mymarid, diapriid and braconid wasps were found in infested sorghum plots. In Johnsongrass plots, 20 times more Hymenoptera were collected from infested plots. Together, the data suggest that sorghum is serving as a pollen food source for hoverflies, earwigs, and bees and sorghum susceptible to SA could provide energy from honeydew. Future research should examine whether planting strips of susceptible sorghum at crop field edges would benefit Hymenoptera and pollinators. Full article
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14 pages, 889 KiB  
Article
Copper Exposure Affects Anti-Predatory Behaviour and Acetylcholinesterase Levels in Culex pipiens (Diptera, Culicidae)
by Nermeen R. Amer, Sharon P. Lawler, Nawal M. Zohdy, Aly Younes, Wael M. ElSayed, Guillaume Wos, Samah Abdelrazek, Hind Omer and Richard E. Connon
Insects 2022, 13(12), 1151; https://doi.org/10.3390/insects13121151 - 14 Dec 2022
Cited by 2 | Viewed by 1493
Abstract
Copper is an essential metal that occurs chronically in the environment and affects the development and physiology of aquatic insects. In excess amounts, it can impair their nervous system and behaviour. We tested the anti-predatory behaviour of Cx. pipiens larvae after seven days [...] Read more.
Copper is an essential metal that occurs chronically in the environment and affects the development and physiology of aquatic insects. In excess amounts, it can impair their nervous system and behaviour. We tested the anti-predatory behaviour of Cx. pipiens larvae after seven days exposure with several concentrations of copper up to 500 mg L−1. We measured responses to non- consumptive (predation cues) and consumptive predation (dragonfly larvae) across two generations. We also tested the accumulated effect of copper on AChE enzyme activity. We exposed half of treated and control larvae to predation cues (water with predator odour and crushed conspecifics) and the other half to water without predation cues. We evaluated total distance moved and velocity. Copper reduced the distance moved and velocity, with stronger effects in the second generation. Copper had no significant effect on larvae eaten by dragonflies. Copper inhibited the AChE enzyme across both generations at 500 µg L−1. Copper can affect the nervous system directly by inhibiting AChE activity, and possibly also by impairing the olfaction sensors of the larvae, resulting in larval inability to detect predation cues. Full article
(This article belongs to the Special Issue Mosquito: Ecology, Behavior and Molecular Biology)
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11 pages, 1491 KiB  
Article
Aphicidal Activity and Phytotoxicity of Citrus sinensis Essential-Oil-Based Nano-Insecticide
by Francesca Laudani, Orlando Campolo, Roberta Caridi, Ilaria Latella, Antonino Modafferi, Vincenzo Palmeri, Agostino Sorgonà, Paolo Zoccali and Giulia Giunti
Insects 2022, 13(12), 1150; https://doi.org/10.3390/insects13121150 - 13 Dec 2022
Cited by 3 | Viewed by 1863
Abstract
Due to its high polyphagy, Aphis gossypii is considered a key pest of many crops, and it can feed on hundreds of plant species belonging to the families Cucurbitaceae, Malvaceae, Solanaceae, Rutaceae, and Asteraceae. The control of this pest mainly relies on synthetic [...] Read more.
Due to its high polyphagy, Aphis gossypii is considered a key pest of many crops, and it can feed on hundreds of plant species belonging to the families Cucurbitaceae, Malvaceae, Solanaceae, Rutaceae, and Asteraceae. The control of this pest mainly relies on synthetic insecticides whose adverse effects on the environment and human health are encouraging researchers to explore innovative, alternative solutions. In this scenario, essential oils (EOs) could play a key role in the development of ecofriendly pesticides. In this study, the development of a citrus peel EO-based nano-formulation and its biological activity against A. gossypii both in the laboratory and field were described and evaluated. The phytotoxicity towards citrus plants was also assessed. The developed nano-insecticide highlighted good aphicidal activity both in the laboratory and field trials, even at moderate EO concentrations. However, the highest tested concentrations (4 and 6% of active ingredient) revealed phytotoxic effects on the photosynthetic apparatus; the side effects need to be carefully accounted for to successfully apply this control tool in field conditions. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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15 pages, 4439 KiB  
Article
Population Parameters and Feeding Preference of Spodoptera litura (Lepidoptera: Noctuidae) on Different Asparagus officinalis Tissues
by Li-Min Ye, Xue-Yuan Di, Bin Yan, Jian-Feng Liu, Xiu-Qin Wang and Mao-Fa Yang
Insects 2022, 13(12), 1149; https://doi.org/10.3390/insects13121149 - 13 Dec 2022
Cited by 2 | Viewed by 1436
Abstract
Spodoptera litura is an important pest that seriously affects Asparagus officinalis production. To clarify the population characteristics and feeding preference of S. litura on different asparagus tissues, asparagus stems and leaves were selected as the research objects, related studies were conducted by constructing [...] Read more.
Spodoptera litura is an important pest that seriously affects Asparagus officinalis production. To clarify the population characteristics and feeding preference of S. litura on different asparagus tissues, asparagus stems and leaves were selected as the research objects, related studies were conducted by constructing the life table and the feeding preference experiment. The results showed that S. litura could complete its development and reproduction normally on asparagus stems or leaves. Although the adult longevity and fecundity of S. litura on the two types of tissues were not significantly different, the development duration of larvae and pupae, and total preoviposition period on leaves were significantly longer than those raised on stems. The intrinsic rate of increase and finite rate of increase were 0.186 d−1 and 1.204 d−1 on stems, which were significantly higher than those fed on leaves (0.161 d−1 and 1.175 d−1). The mean generation time on stems (32.88 d) was significantly lower than on leaves (36.88 d). It indicated that stems were more suitable for its population growth. In the feeding preference, the third and fifth instar larvae preferred to feed on leaves, and other instar larvae (except for the sixth instar of 2.5 h) had no significant difference. These results will provide a theoretical reference for further research and forecasting and integrated control. Full article
(This article belongs to the Section Insect Physiology, Reproduction and Development)
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12 pages, 3726 KiB  
Article
A New Species of Ascodipteron (Diptera: Hippoboscidae) from China Based on Morphology and DNA Barcodes
by Haoran Sun, Liang Ding, Thomas Pape and Dong Zhang
Insects 2022, 13(12), 1148; https://doi.org/10.3390/insects13121148 - 13 Dec 2022
Viewed by 1523
Abstract
A new species of the genus Ascodipteron Adensamer, 1896 (Diptera: Hippoboscidae) is described from Fujian, namely A. guoliangi sp. nov. Habitus and diagnostic details, as well as the attachment sites on the host, are documented with photographs. A detailed comparison of the [...] Read more.
A new species of the genus Ascodipteron Adensamer, 1896 (Diptera: Hippoboscidae) is described from Fujian, namely A. guoliangi sp. nov. Habitus and diagnostic details, as well as the attachment sites on the host, are documented with photographs. A detailed comparison of the new species with related species is provided and the new species is accommodated in the most recent key to the world species of Ascodipteron. Full article
(This article belongs to the Special Issue Diptera Diversity in Space and Time)
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