Insects

14 pages, 1942 KiB

Open AccessArticle

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 10 | Viewed by 3922

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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Mean duration (± SE) of developmental stages ((A): larval duration; (B): pupal duration; (C): adult longevity; (D): total longevity) and pupal mass (E) of female and male Spodoptera frugiperda individuals fed different diets. Full article ">Figure 2
Age-stage survival rate (sxj) of Spodoptera frugiperda individuals fed different diets. (A): D1; (B): D2; (C): D3; (D): D4; (E): maize leaves. Full article ">Figure 3
Age-specific survival rate (lx), age-specific fecundity of female adults (fx), age-specific fecundity (mx), and age-specific maternity (lxmx) of Spodoptera frugiperda individuals fed different diets. (A): D1; (B): D2; (C): D3; (D): D4; (E): maize leaves. Full article ">Figure 4
Age-stage specific life expectancy (exj) of Spodoptera frugiperda individuals fed different diets. (A): D1; (B): D2; (C): D3; (D): D4; (E): maize leaves. Full article ">

32 pages, 13296 KiB

Open AccessArticle

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 2041

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

Open AccessEditor’s ChoiceArticle

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 2007

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 (CONFOUND_SBW) 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 CONFOUND_SBW 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 CONFOUND_SBW 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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Location of treatment (red) and control (green) sites 1–10, used in the 2021 large-scale mating disruption field trial with CONFOUNDSBW. Darker region: north-eastern New Brunswick, Canada; Paler region: south of the Gaspe Peninsula, Quebec, Canada. Full article ">Figure 2
Placement of pheromone traps in 5 clusters of 3 traps each within 300 ha study Block 2, as example. Traps within clusters were spaced 30 m apart. Full article ">Figure 3
Configuration of the spray deposit calibration trial conducted at the Charlo airport, NB. Full article ">Figure 4
Mean (±SEM) proportion of shoots with at least one spray droplet on branches collected within blocks treated with CONFOUNDSBW. Green: balsam fir; red: spruces; dark: current-year shoots; pale: older shoots. Full article ">Figure 5
Mean (±SEM) adult SBW catch in pheromone traps. (a) In treated and (b) untreated blocks between June 30 and 19 August 2021. Block numbers in top right corners of panels. (c) Trap catch in center and at edges of blocks (Red: treated; blue: controls; dark: center; pale: edge). Full article ">Figure 6
Relationship between pupal case (adult) density and (a) egg density or (b) apparent fecundity (eggs per adult). Means ± SEM; blue: control blocks; red: treated blocks. Line in (a) is Equation (1). Line in (b) has slope −0.299 ± 0.148, but this relationship did not reach significance (α = 0.05). Potential SBW fecundity is around 100 eggs/moth. Full article ">Figure 7
Relationship between spring L2 density and (a) fall L2 density or (b) population growth rate (from L2s to L2f). Means ± SEM; blue: control blocks; red: treated blocks. Line in (a) is Equation (2). Line in (b) has slope 0.755 ± 0.385, but this relationship did not reach significance (α = 0.05). Full article ">

8 pages, 881 KiB

Open AccessArticle

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 2005

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

Open AccessArticle

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

Cited by 2 | Viewed by 1994

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

Open AccessArticle

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 4 | Viewed by 2975

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

Open AccessArticle

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 2 | Viewed by 1650

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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Aedeagi of Mesolycus species: (A–C,G). M. rubromarginatus Kazantsev, 2013; (D–F,H). M. dentatus sp. n.; (K–M,I). M. qinlinganus Kazantsev, 2000; (N–P,J). M. shaanxiensis sp. n.: (A,D,K,N)—ventrally; (B,E,L,O)—dorsally; (C,F,M,P)—laterally; (G–J)—apically. Scales: (A–G,I–P), 0.5 mm; (H), 0.2 mm. pl—plate; br—basal rods; ph—phallus; pb—phallobase; ar—apical ring; ap—apical hood; lp—lower plate; up—upper plate; pr—ventro-apical process. Full article ">Figure 2
Male habitus of Mesolycus species: (A). M. dentatus sp. n.; (B). M. qinlinganus (Kazantsev, 2000); (C). M. shaanxiensis sp. n.; (D). M. varus sp. n.; (E). M. breviplatus sp. n.; (F). M. murzini Kazantsev, 2004. Scales: 1.0 mm. Full article ">Figure 3
Aedeagi of Mesolycus species: (A–C,J). M. varus sp. n.; (D–F,K). M. breviplatus sp. n.; (G–I,L). M. murzini Kazantsev, 2004. (A,D,G)—ventrally; (B,E,H)—dorsally; (C,F,I)—laterally; (J–L)—apically. Scales: (A–I,K), 0.5 mm; (J,L), 0.2 mm. pl—plate; br—basal rods; ph—phallus; pb—phallobase. Full article ">Figure 4
Distribution map of Mesolycus in the world scale (The red represents the atrorufus group and the green denotes the ilyai group). Full article ">Figure 5
Phylogenetic tree of Lycinae produced from the ML (right) and BI (left) analyses based on the cox1, nad5, cox2 and Lrna genes. The numbers on the branches represent bootstrap (BS) (right) and posterior probability (PP) (left), respectively. Dilophotini is circled in orange and Macrolycini in green box. The pentagram represents Mesolycus species used in this study. Full article ">

22 pages, 2625 KiB

Open AccessArticle

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 2410

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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Lifecycle and development of compound eyes of M. mongolica during 5th-instar nymphal stage and adult stage (A) Lifecycle of M. mongolica, adapted with permission from Ref. [<a href="#B19-insects-13-01170" class="html-bibr">19</a>]. (B) Head including compound eyes of an adult. (C) Ultrastructure of compound eyes of the adult after emergence at 3 h (A3). (D) Ultrastructure of compound eyes of the adult after emergence at 48 h (A48). (E) Head including white compound eyes of a nymph. (F) Head including compound eyes of a nymph with red eyes. (G) Head including dark-brown compound eyes of a nymph. (H) Structure of a white compound eye in 5th-instar nymphal stage (N5W). (I) Structure of a red compound eye in 5th-instar nymphal stage (N5R). (J) Structure of a dark-brown compound eye in 5th-instar nymphal stage (N5B). Full article ">Figure 2
Functional enrichment analysis of profile-specific DEGs (GO terms and KEGG pathways). GO function and KEGG pathway enrichment analyses were performed on DEGs in the 10 profiles, respectively. The significantly-enriched gene sets (p-value < 0.01, Enrichment Fold > 5) were focused and analyzed, which are related to specific biological functions including coloration, phototransduction, hormonal regulation, innate immune response and cuticle development, respectively. Full article ">Figure 3
Expression patterns of key DEGs related to pigmentation. Ommochrome biosynthesis pathway is related to the genes encoding tryptophan 2,3-dioxygenase (TDO), kynurenine 3-monooxygenase (KMO), two ABC transporters (white and scarlet). Melanin biosynthesis pathway is related to the genes encoding tyrosine hydroxylase (TH), NBAD hydrolase (Tan), NBAD synthase (ebony), DOPA decarboxylase (DDC), aspartate 1-decarboxylase (ADC), laccase (lac2, two genes), and yellow protein (three genes). The heatmaps based on TPM show the expression levels of the corresponding protein or enzyme genes in five development stages (From left to right, the 5th-instar with white compound eyes (N5W), with red compound eyes (N5R), with dark brown compound eye (N5B), the adults after emergence at 3 h (A3), 48 h (A48). Full article ">Figure 4
Heatmap of key genes in comparable groups of N5W vs. N5R, N5R vs. N5B, N5B vs. A3, and A3 vs. A48. The log2 fold change-values based on analysis of differentially expressed genes are indicated in the heatmap, which are all at significant level p-value < 0.01. No significant differences are marked as “n. s”. Full article ">Figure 5
Expression patterns of key DEGs related to structure of visual system. Chromophore de novo synthesis and regeneration is related to the genes encoding retinoid-binding protein (Pinta, two genes (non DEGs)), β, β-carotene-15,15′monooxygenase (NinaB, two genes), photoreceptor dehydrogenase (PDH, four genes). Phototransduction is related to the genes encoding Ca2+-permeable light-sensitive transient receptor potential channel (TRP), Ca2+-permeable light-sensitive transient receptor potential-like channel (TRPL), myosin III (NinaC), arrestin homologs (two genes), opsins (four genes). The heatmaps based on TPM show the expression levels of the corresponding protein or enzyme genes in five development stages (from left to right, the 5th-instar with white compound eyes (N5W), with red compound eyes (N5R), with dark brown compound eye (N5B), and the adults after emergence at 3 h (A3), 48 h (A48)). Full article ">Figure 6
Expression analysis of six genes related to phototransduction and phylogenetic analysis of four opsin genes in M. mongolica. (A–E) RNA-seq gene expression levels of MmLop1, MmLop2, MmBLop1, MmUVop1, TRP and TRPL on five development stages (N5W, N5R, N5B, A3, A48). The 5th-instar with white compound eyes (N5W), with red compound eyes (N5R), with dark brown compound eye (N5B), and the adults after emergence at 3 h (A3), 48 h (A48). (F) The phylogenetic tree was based on the maximum likelihood (ML) method. Different opsin nucleotide sequences are grouped into four clusters, which belong to three orders and an outgroup, and are assigned with different colors. Numbers at nodes indicate the bootstrap values. The 29 sequences are indicated by the corresponding scientific names of species followed by their gene names and accession numbers. The sequences of four opsins studied in our study are indicated by solid red rectangular boxes. Full article ">Figure 7
Expression patterns of key DEGs related to hormone biosynthesis. Ecdysteroid biosynthesis pathway is related to the genes encoding ecdysteroid 25-hydroxylase (phm), ecdysteroid 22-hydroxylase (dib), and ecdysteroid 2-hydroxylase (sad), ecdysteroid 20-hydroxylase (shd). MEKRE93 pathway is related to the gene encoding the Krüppel homolog 1 (Kr-h1). The heatmaps based on TPM show the expression levels of the corresponding protein or enzyme genes in five development stages (from left to right, the 5th-instar with white compound eyes (N5W), with red compound eyes (N5R), with dark brown compound eyes (N5B), and the adults after emergence at 3 h (A3), 48 h (A48)). Full article ">

20 pages, 4394 KiB

Open AccessFeature PaperArticle

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

Cited by 3 | Viewed by 2404

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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Predicted binding modes of OA-02, OA-06 and OA-09. (A–D) Sticks model representation of OA-02 (Brown), OA-06 (White), OA-09 (Yellow) and Cholesterol (Blue) binding with active site. (E) Interactions of Cholesterol with the binding pocket. (F) Representation of binding modes of selected compounds aligned on cholesterol in the binding pocket showing in surface. Full article ">Figure 2
The binding stability analysis of protein–ligand complexes by MD Simulation. (A) RMSD plots of backbone of protein (blue) and its complexes OA-02 (black), OA-06 (red) and OA-09 (green). (B) The RMSD plots of ligands. (C) The residual flexibility analysis of the protein and complexes. (D) The solvent exposed area analysis of protein and its complexes. Full article ">Figure 3
Mean mortality percentages of (A) 3rd instar (Compound: H = 6.33; df = 2; p = 0.042 and Concentration: H = 9.30; df = 2; p = 0.026), (B) 4th instar (Compound: H = 4.31; df = 2; p = 0.116 and Concentration: H = 5.91; df = 2; p = 0.116) and (C) 5th instar larvae (Compound: H = 3.75; df = 2; p = 0.056 and Concentration: H = 2.114; df = 2; p = 0.486) of Helicoverpa armigera when treated with different concentrations of OA-02, OA-06 and OA-09 compounds. The data were subjected to nonparametric Kruskal–Wallis H test. Full article ">Figure 4
Effect of different concentrations of OA-02, OA-06 and OA-09 compounds on 3rd–5th instar H. armigera larval (A–C) and pupal weights (D). The data were subjected to a 2-way ANOVA (statistics for the effects of compound type for 3rd–5th instar larval weight and pupal weight: F2, 24 = 4.301; p = 0.025, F2, 24 15.552; p < 0.001, F2, 24 = 20.407; p < 0.001 and F2, 24 = 0.156; p = 0.856, respectively while the statistics for the effect of their concentrations: F2, 24 = 1.003; p = 0.408, F2, 24 = 0.904; p = 0.454, F2, 24 = 1.083; p = 0.375 and F2, 24 = 5.640; p = 0.005, respectively). The bars represent mean ± SEM and the superscript uppercase and lowercase letters atop each bar represent the post-hoc pairwise comparisons between different compounds and concentrations, respectively. The bars with different letters are significantly different from each other (p < 0.05). Full article ">Figure 5
Age-specific survival (lx) and age-specific fecundity (mx) of Helicoverpa armigera when treated with OA-02, OA-06 and OA-09 compounds. Full article ">

12 pages, 921 KiB

Open AccessArticle

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 3 | Viewed by 2476

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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Figure 1
Survival of CPB larvae at different stages after topical infection with M. robertsii (5 × 106 conidia/mL). Recently molted larvae were infected at 2 h post-molt in instar IV. Finishing feeding larvae were infected at 86 h post-molt in instar IV. Different letters show significant differences in survival dynamics (log rank test, χ2 > 110.3, df = 1, p < 0.0001). Full article ">Figure 2
Changes in expression of immunity- and stress-related genes during the intermolt period in CPB larvae (instar IV, no infection). Data are presented as fold changes relative to uninfected larvae at 26 h post-molt. Genes rp18, arf2, and arf19 were used as references. * p < 0.05, ** p < 0.01, and *** p < 0.001 relative to larvae at 26 h post-molt (Dunn’s test). Full article ">Figure 3
Alterations of expression of immunity- and stress-related genes in different stages of CPB larvae at 24 h post-inoculation (HPI) and 72 HPI with M. robertsii (5 × 106 conidia/mL). Data are presented as fold changes relative to an uninfected control in each stage at each time point. Genes rp18, arf2, and arf19 were used as references. * p < 0.05, ** p < 0.01 relative to uninfected controls (Dunn’s test). # Significant differences in expression between infected recently molted larvae and infected finishing feeding larvae (Dunn’s test, p < 0.05). Full article ">

14 pages, 2545 KiB

Open AccessArticle

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

Cited by 6 | Viewed by 2127

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 Social Insects and Apiculture)

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Figure 1
The effect of survival and food consumption under acetamiprid exportation and A. kunkeei addition for honeybees. (a) The survival of honeybees under acetamiprid exportation and A. kunkeei addition. (b) Consumption of food for a total of six days under acetamiprid exportation and A. kunkeei addition. (c) Impact of acute oral exposure to acetamiprid and of A. kunkeei addition. ‘*’ represents a statistically significant difference between the two groups at p < 0.05. ‘**’ represents a statistically significant difference between two groups at p < 0.01. Full article ">Figure 2
Composition of operational taxonomic units of the intestinal bacteria of honeybees. The number demonstrates the number of OTU, and different colors represent different groups. Full article ">Figure 3
Relative and absolute abundances of the dominant intestinal bacteria of honeybees (genus level). Each bar represents the relative and absolute abundance of each genus in each sample. The transformed absolute abundances were total 16S rRNA gene copies transformed into relative abundance percentages, which provides a crude metric showing how the numbers of each species varied in the four groups. Full article ">Figure 4
The total 16S gene and A. kunkeei copies of intestinal bacteria of honeybees. ‘*’ represents a statistically significant difference between two groups (independent-sample t test, p < 0.05). Full article ">Figure 5
Significant differences in the bacteria in honeybees at the species levels. (a) Significant differences between species in the CK and A groups. (b) Significant differences between species in the CK and L groups. (c) Significant differences between species in the A and AL groups. Each bar represents the relative abundance of each species. Full article ">Figure 6
Biological diversity of intestinal bacteria in honeybees at the α level. The level of intestinal bacteria diversity was determined by comparing: the observed species index (a); the Shannon evenness index (b); the status and queues in the cluster index (c); and the phylogenetic diversity index (d). ‘*’ represents a statistically significant difference between two groups (independent-sample t test, p < 0.05). ‘**’ represents a statistically extremely significant difference between two groups (independent-sample t test, p < 0.01). Full article ">Figure 7
Biological diversity of intestinal bacteria in honeybees at the β level, assessed using: (a) principal component analysis; (b) principal coordinate analysis; and (c) nonmetric multidimensional scaling. Different colors represent different groups. The circle represents confidence ellipse. Full article ">

16 pages, 2483 KiB

Open AccessArticle

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 4 | Viewed by 3507

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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Figure 1
Nighttime, near-infrared image capture of spiders, their bolases, and the moths with which they interact. All images collected in the field. (A) Mastophora hutchinsoni dangling its bolas, with the large glue droplet, nearly 2 mm in diameter, clearly resolved in this still image. (B) The moth approaches the bolas spider slowly in a path (blue) that zigzags, presenting the spider (path in purple) with a target that is close and stable. This example is typical for five of the six of the capture events recorded. It is important to note that the displacements, velocities, and accelerations that we calculated from a single high-speed camera would have underestimated the magnitudes of those properties when the motions moved out of the visual plane that was perpendicular to the camera. Full article ">Figure 2
Humidity influenced the making of bolases but not the proportion of spiders who were active. (A) Relative humidity did not predict the proportion of spiders that were active. Each point represents observations of multiple spiders on a single tree during a single observation session. (B) Relative humidity correlates positively with the number of bolases created. Each point represents all observations on a given day. Full article ">Figure 3
Bolas spider capturing a moth by flicking its bolas. In four of five successful capturing events, the spider and moth interacted in five phases, four of which are shown here (top). The distance between the spider and the moth, denoted as range (bottom), quantifies the dynamics of the struggle, with the colors of the lines corresponding to the phases above. Full article ">Figure 4
Behavior of the bolas during capture. The spider flicks its bolas towards the moth (off screen to the right). In the original image (A), a still from the high-speed video, the bolas can be seen as it stretches. Enhancement of the image (B), by increasing the exposure and contrast, more clearly shows the structure of the droplet as it stretches; the liquid phase of the droplet (white) remains associated with the thread of the windlass as it unfurls. The droplet continues to be tethered to the spider by the radial thread, which also stretches (C). The spider reels in the moth (D,E). In the original image (D) the spider is hauling in the radial thread as the moth dangles from the stretched droplet. In the enhanced image (E), the scales attached to the droplet can be seen as a large clump (elliptical white structure) and smaller clumps (smaller white regions) on the windlass. The stretched droplet forms an elongated adhesive region (F), with a large clump (large arrow) and small clumps (small arrows) that were created during the initial deposition of the glue droplet onto the moth. Full article ">Figure 5
Speculative model of a bolas interacting with the scaled surface of the moth. The bolas has a viscous glue droplet containing a windlass of coiled silk. The flicking force of the spider stretches the glue droplet, with the internal silk of the windlass allowing it to stretch, spring-like, and to retain the liquid phase. If the droplet fails to hit the moth, the glue droplet returns elastically to its original spherical form. If the droplet hits the moth, the collision with the substrate initially dislodges scales. The tension on the thread, caused by the escaping moth, begins to unravel the windlass as it is pulled through the glue, causing the glue to spread within the matrix of the scales. The hydrophobic nature of the scales causes them to be pulled to the surface and pulled upward, cleaning the area and allowing the remaining glue to connect with the underlying cuticle. As the tethered moth struggles to escape, angular momentum is generated, leading to further contact between the glue droplet and moth substrate. The interactions of the bolas, both liquid phase and windlass, with the scales of the moth, are speculative, based on previous work of glue spreading in the previously analyzed moth-specialist, C. akirai. Full article ">Figure 6
The dynamic behavior of the bolas during flicking, modeled as a simple mass-spring-damper system. The glue droplet is held steady with the leg in a horizontal orientation (top-most position). As the spider swings its leg, the inertia of the flicked glue droplet carries it forward until it reaches the end of its arc. At this moment, the kinetic energy is transduced into elastic energy in the radial thread and the droplet, stretching both (see <a href="#insects-13-01166-f004" class="html-fig">Figure 4</a>A–C). The system has two springs: (1) the radial thread and (2) the glue droplet, forming the mass-spring-damper system as in the diagram in the inset. The springs are represented by zig-zagged lines, the damper is a piston, and the center of mass is shown by the blue square, m. This model is a first-approximation and, thus, is likely to be highly simplified compared to the actual behavior of the system, which has yet to be determined. Full article ">Figure 7
Mass-spring-damper estimates of bolas stretch and velocity. Underdamped <math display="inline"><semantics> <mrow> <mi>ζ</mi> <mo><</mo> <mo><</mo> <mn>1</mn> <mo>;</mo> <mo> </mo> </mrow> </semantics></math>critically damped <math display="inline"><semantics> <mrow> <mi>ζ</mi> <mo>=</mo> <mn>1</mn> <mo>;</mo> <mo> </mo> </mrow> </semantics></math>overdamped <math display="inline"><semantics> <mrow> <mi>ζ</mi> <mo>></mo> <mo>></mo> <mn>1</mn> </mrow> </semantics></math>. Three models for the damping coefficient resulting in the three types of behavior. Two lines share the common y-axis with varying units; yellow lines depict estimated droplet velocity (cm s−1) and blue lines the droplet’s stretch from its initial position (cm). The x-axis shows time in seconds. The critically damped model yields the behavior that most closely matches actual behavior of the glue droplet. The underdamped one oscillates too much, and the glue droplet stretches too far. The overdamped does not stretch nearly as far as measured. Full article ">

20 pages, 3244 KiB

Open AccessArticle

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

Cited by 1 | Viewed by 2758

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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Figure 1
The effect of variable larval salt concentration on life history traits of Anopheles merus. (A) Time-to-pupation in different larval salt concentrations. Asterisks (*) indicate a significant difference from the untreated control. (B) Adult longevity of female An. merus after rearing in different larval salt exposures. (C) Fertility and fecundity of adults reared in different larval salt concentrations. Blue bars represent number of eggs, and the orange line represents hatch percentage. Blue asterisks represent a significantly different number of eggs from the control. Orange asterisks represent a significantly different hatch percentage from the untreated control. (D) Deltamethrin lethal time of adults reared in different larval salt concentrations. Asterisks indicate a significant difference from the untreated control. Full article ">Figure 2
Relative normalised expression of defensin-1 transcripts from An. Merus adults reared in different larval salt concentrations. Asterisks (*) denote a significant difference from the untreated control. Circles (●) indicate a significantly lower expression in the treated groups. Full article ">Figure 3
Alpha diversity of adult An. merus gut microbiota. (A) Chao1 index (species richness). (B) Simpson index (species evenness). Values indicate p-values from Kruskall–Wallis ANOVA. Full article ">Figure 4
Beta diversity of 4th instar larvae and adult An. merus reared in differing larval salt concentration. Non-Metric Multidimensional Scaling plot of β-diversity. Larvae (triangles) from different salt concentrations cluster separately from the adults (circles) and are diverse from each other. Adults are also less diverse and their diversities overlap. Full article ">Figure 5
Overlapping gut microbiota in An. merus reared in varying larval salt concentrations. (A) Overlapping species in adults originating from larval different treatments. (B) Overlapping species in adults and larvae. Individual dots indicate numbers of individual species. Joined dots indicate numbers of shared species between the relevant concentrations. Full article ">Figure 6
Phylogenetic tree of 16S rRNA sequences from Anopheles merus adults and larvae from different salt concentrations. Using the alignment of classified OTU sequences, the maximum likelihood tree was constructed using RAxML with the GTRGAMMAIX model and 1000 bootstraps. Taxa under the same genus were collapsed and their overall OTU abundance percentages are provided within the parentheses. Full article ">Figure 7
Differential abundance of microbiota in treatments compared to a 50% seawater treatment. Genera to the left of 0 are abundant in the 50% treatment, while genera to the right of 0 are abundant in the comparative concentration. (A) Adult 50% compared to 0% treatment. (B) Adult 50% compared to 6.25% treatment. (C) Adult 50% compared to 12.5% treatment. (D) Adult 50% compared to 25% treatment. Genera with asterisks have been associated with protection against Plasmodium. Full article ">

11 pages, 5749 KiB

Open AccessArticle

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 12 | Viewed by 2453

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

(This article belongs to the Special Issue A Themed Issue in Honor of Prof. Dr. Xin-Hua Wang on the Occasion of His 70th Birthday: Diversity, Ecology and Evolution of Aquatic Insects)

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Figure 1
Mitogenome map of representative species of Chironomus (Chironomus annularius). The arrow indicates the direction of gene transcription. PCGs and rRNAs are represented by normative abbreviations, while tRNAs are represented by single-letter abbreviations. In the notes at the bottom right, green, red, blue, and yellow respectively corresponded to PCGs, tRNAs, rRNAs, and CR. The second circle shows the G+C content of the complete mitogenome. The third circle exhibits the GC-skew of the whole mitogenome. The innermost circle shows the morphology of the larvae of Chironomus annularius and the length of the mitogenome. Full article ">Figure 2
Amino acid distribution of mitogenomes of 15 Chironomus species. The x axis represents the codon families, and the y axis represents the total codon. Full article ">Figure 3
Evolution rate of 13 PCGs of mitogenomes of 15 Chironomus species. Ka refers to non-synonymous nucleotide substitutions, Ks refers to synonymous nucleotide substitutions, Ka/Ks refers to the selection pressure of each PCG. The x axis represents 13 PCGs, and the y axis represents the value. Full article ">Figure 4
Heterogeneity analysis based on 13 PCGs and two rRNA sequences. Analysis based on AliGROOVE scores ranging from −1 (strong heterogeneity between datasets; the color is red) to +1 (weak heterogeneity between datasets; the color is blue); the lighter the color of the color block of each dataset, the stronger the heterogeneity, and the darker the color, the weaker the heterogeneity. Full article ">Figure 5
Phylogenetic trees of Chironomus inferred from the PCG123R dataset. (a) BI tree. Numbers at the nodes were BI posterior probabilities. (b) ML tree. Numbers at the nodes were ML bootstrap values. Full article ">

12 pages, 1894 KiB

Open AccessArticle

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 3 | Viewed by 1905

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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Figure 1
Expression of the silk-coding genes in different silkworm groups. Improve, the improved silkworm (Bombyx mori) strains; Local, the early domesticated silkworm (B. mori) strains; Wild, the wild silkworm (B. mandarina) different geographical individuals. (A) Expression of silk fiber protein genes. (B) Expression of the for the sericin genes. Full article ">Figure 2
Differentially expressed genes (DEGs) in the silk gland among the wild, the early domestic and improved silkworms. (A) Venn scheme of the pairwise differentially expressed genes among different silkworm groups; (B) heatmap and hierarchical cluster of all the DESs among different silkworm groups. I, the improved silkworm (B. mori) strains; L, the early domestic silkworm (B. mori) strains; Wild, the different wild silkworm (B. mandarina) geographical individuals. (C) Information of the improved silkworm-specific differentially expressed genes (IS-DEGs). Up, up-regulated; Down, down-regulated. Full article ">Figure 3
Functional enchainment and the tissue expression pattern of the 1671 improved silkworm-specific DEGs (IS-DEGs). (A) Functional enrichments of up-regulated (pink) and down-regulated IS-DEGs (green). (B) Tissue expression pattern of the IS-DEGs in the enriched biological processes and pathways in the local strain (P50) of the domestic silkworm. MPT, Malpighian tubule; ASG\MSG\PSG, anterior\Middle\Posterior silk gland; L5D3, the 3rd day of the 5th instar larval stage; W, the wandering stage. Full article ">Figure 4
Expression and selection signature of the five candidate improvement genes. (A) Heat map of the expression in the silk glands of the five candidate improvement genes in different silkworm strains or individuals. I, the improved silkworm (B. mori) strains; L, the early domestic silkworm (B. mori) strains; Wild, the different wild silkworm (B. mandarina) geographical individuals. (B) Heat map of the tissue expression of the five candidate improvement genes in the local strain (P50) domestic silkworm. MPT, Malpighian tubule; ASG\MSG\PSG, anterior\Middle\Posterior silk gland respectively; L5D1/L5D3, the 1st/3rd day of the 5th instar larval stage; W, wandering stage. (C) Selection signatures for the five candidate improvement genes. The Fst plottings of each silkworm groups against wild silkworms (the top panel) and early domestic silkworm strains (the mid panel), as well as the π (the bottom panel) plotting are shown, along the genomic regions covering the five genes. Dashed lines represent the top 1% of values, respectively. Full article ">

14 pages, 825 KiB

Open AccessArticle

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 10 | Viewed by 2870

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

Open AccessArticle

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 4 | Viewed by 2195

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

Open AccessArticle

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 11 | Viewed by 2985

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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The effect of Rickettsia infection on the fecundity (a), hatching rate (b), developmental du-ration (c), survival rate from egg to adult (d), sex ratio (% female) (e) and longevity (f) of Bemisia tabaci MEAM1 cryptic species. R+: Rickettsia positive population; R−: Rickettsia negative population. Data were compared among treatments using t-test, and stars over the bars *, **, **** signify differences were significantly different at 0.05, 0.01 and 0.0001 levels respectively, ns signifies differences were not significant. Full article ">Figure 2
The effect of Rickettsia infection on the glycogen content (a), soluble sugar content (b), trehalose content (c) and protein content (d) of Bemisia tabaci MEAM1 cryptic species. R+: Rickettsia positive population, R−: Rickettsia negative population. Data were compared among treatments using t-test, and stars over the bars * signify differences were significantly different at 0.05 level respectively, ns signifies differences were not significant. Full article ">Figure 3
The infection phenotype of Bemisia tabaci MEAM1 nymphs treated with Akanthomyces at-tenuatus (1 × 108 conidia/mL). Panels (a-1,a-2) were healthy 3rd nymphs and the fungus-infected 3rd nymphs, (b-1,b-2) were healthy 2d age pupae and the fungus-infected 2d age pupae, (c-1,c-2) were healthy newly emerged adults and the fungus-infected newly emerged adults of Rickettsia negative B. tabaci on the 5th day after infection. Full article ">Figure 4
The effect of Akanthomyces attenuatus SCAUDCL53 on the mortality rate of the first instar (a), second instar (b), third instar (c) and fourth instar (d) nymphs of Rickettsia positive (R+) and Rickettsia negative (R−) B. tabaci MEAM1 cryptic species. Full article ">Figure 5
The effects of Rickettsia infection in B. tabaci MEAM1 on the parasitism of Encarsia formosa. (a) parasitism rate, (b) developmental duration of E. formosa F1 larvae, (c) emergence rate of E. for-mosa F1 adults. R+: Rickettsia positive population, R−: Rickettsia negative population. Data were com-pared among treatments using t-test, and stars over the bars *, ** indicate that differences were significantly different at 0.05 and 0.01 levels respectively, ns indicate that differences were not significant. Full article ">Figure 6
The effects of imidacloprid and spirotetramat on the mortality of second instar nymphs (a,c), adults (b,d) of Rickettsia positive and Rickettsia negative B. tabaci MEAM1 cryptic species. R+: Rickettsia positive population, R−: Rickettsia negative population. Control treatment (CK) was ddH2O. Full article ">

14 pages, 1221 KiB

Open AccessArticle

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

Cited by 2 | Viewed by 2352

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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Localization of rDNA in Rhionaeschna bonariensis (n = 12 + neo-XY) (a–d) and Aeshna cyanea (2n = 27) (e,f) by FISH with 18S and 28S rDNA probes, respectively (red signals). (a) Pachytene; (b) early diakinesis; (c) diakinesis; (d) prometaphase I, inset: Giemsa-stained neo-XY bivalent from another cell, *: early spermatid with rDNA signal; (e,f) the same spermatogonial prometaphase: (e) composite FISH image; (f) DAPI staining; arrows point to secondary constrictions. Bar = 10 µm. Full article ">Figure 2
Rhionaeschna planaltica (2n = 16, n = 7 + neo-XY). Localization of rDNA by FISH with 18S rDNA probes (red signals) (a–g). Giemsa staining (inset in f). (a,c) Spermatogonial prometaphase; (b,d,e) pachytene; inset in (b): schematic drawing of the neo-XY bivalent (neo-X in white, neo-Y in blue, probe signals in red); (f) diakinesis, inset: neo-XY bivalent; (g) metaphase I; (c) shows a neo-X chromosome to illustrate the subterminal position of the signal; (d,e) show selected neo-XY bivalents from other cells. Bar = 10 µm. Full article ">Figure 3
GISH in Rhionaeschna bonariensis (n = 12 + neo-XY). The male gDNA probe was labeled with Cy3-dCTP (red). (a) Pachytene; (b) diplotene; (c,d) diakinesis; (e) prometaphase I; (f) prophase II; (g,h) spermatids with (g) and without (h) hybridization signals. Arrowheads in (b) indicate weak hybridization signals in some telomeric regions of autosomal bivalents. Insets in (d,f) show selected neo-XY bivalents from other cells. Bar = 10 µm. Full article ">Figure 4
Schematic interpretation of chromosomal rearrangements in the evolution of neo-X and neo-Y chromosomes and meiotic configurations in Rhionaeschna planaltica. (a) Autosomal m-chromosome pair (black) and single X chromosome (green) with subterminal rDNA cluster, i.e., NOR (red). (b) Insertion of the X chromosome into one-third of one m-chromosome (neo-X). The NOR is located in the region of the X chromosome that was connected to the smaller part of the m-chromosome. (c) Pachytene pairing of the neo-XY bivalent with a crossing-over (orange) in the smaller pairing segment. (d) Heteromorphic sex chromosome bivalent in diakinesis with NOR near the chiasma. Full article ">Figure 5
Simplified phylogenetic tree of Rhionaeschna species with known diploid chromosome number and sex chromosome constitution in males constructed according to the cladogram published in a previous study [<a href="#B33-insects-13-01159" class="html-bibr">33</a>]. Species examined in this study are shown in red. Full article ">

17 pages, 2273 KiB

Open AccessArticle

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 3 | Viewed by 1837

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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Age-stage specific survival rate (sxj) (A) and age-stage specific predation rate (cxj). (B) of O. minutus starting from 100 eggs fed on D. minowai at different temperatures. Full article ">Figure 2
Age-specific survival rate (lx), age-stage specific fecundity (fx7) (i.e., female adult is the 7th life stage), age-specific fecundity (mx), age-specific maternity (lxmx) of O. minutu at different temperatures. Full article ">Figure 3
Age-specific survival rate (lx), age-specific predation rate (kx) and age-specific net predation rate (qx) of Orius minutus at different temperatures. Full article ">Figure 4
(A) Age-specific life expectancy (exj) and (B) age-stage reproductive value (vxj) at five different temperatures. Full article ">Figure 5
Simulation of O. minutus population fed on D. minowai starting from 10 eggs at five temperatures from 15 to 35 °C through a period of 120 d. Full article ">Figure 6
Simulation of D. minowai population size starting from 200 eggs at different constant temperatures. Full article ">Figure 7
Simulated population growth of D. minowai starting form 200 eggs with five pairs of adults O. minutus released on the tenth day. Predation potential is the predation ability of O. minutus to D. minowai at time t. Full article ">

8 pages, 542 KiB

Open AccessArticle

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 8 | Viewed by 3416

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

Open AccessArticle

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 3 | Viewed by 2302

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

Open AccessFeature PaperArticle

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 3 | Viewed by 2946

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

(This article belongs to the Special Issue Systematics, Phylogeny, Evolution and Diversity of True Bugs (Hemiptera: Heteroptera))

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(A) Dorsal view of Cimex hemipterus male taken with the Zeiss Axio Imager M2 with the scale 0.5 mm. Illustration of the linear measurements applied to the pronotum and used as input for the linear morphometry. pw, pronotum width; pm, pronotum length (medial); pc, anterior pronotal concavity depth. (B) Picture illustrating the pseudolandmarks (white dots) digitized along the pronotum contour and used as input for the outline-based morphometry. Full article ">Figure 2
Quantile boxes showing the relative variation in the global size of the pronotum. Variations in size among males (left) and females (right) were derived via (A) the linear approach (log-size) and (B) outline-based morphometry (semi-major axis of the first ellipse). Boxes show group medians that separate the 25th and 75th percentiles. Full article ">Figure 3
Group means of the ectoparasite outlines, with X and Y axes as reconstructed coordinates after inverse Fourier function. Full article ">Figure 4
Shape-based hierarchical agglomerative clustering analysis derived from either log-shape ratios (A) or normalized elliptic Fourier coefficients (B) between males and females. Individuals are plotted on the horizontal axis as operational taxonomic units (OTU). Capital letters P, C, and S indicate the affiliated species, as to Paracimex sp. (P), Cimex hemipterus (C), and Stricticimex parvus (S). Full article ">Figure 4 Cont.
Shape-based hierarchical agglomerative clustering analysis derived from either log-shape ratios (A) or normalized elliptic Fourier coefficients (B) between males and females. Individuals are plotted on the horizontal axis as operational taxonomic units (OTU). Capital letters P, C, and S indicate the affiliated species, as to Paracimex sp. (P), Cimex hemipterus (C), and Stricticimex parvus (S). Full article ">

27 pages, 9965 KiB

Open AccessArticle

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 7 | Viewed by 1971

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

Open AccessArticle

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 5 | Viewed by 3323

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

(This article belongs to the Special Issue The Impact of Environmental Changes on Insects Behavior, Physiology and Biochemistry)

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The baroque facade of the Casa do Cabildo house, built in 1758, illuminated by the CromaLux lighting. Full article ">Figure 2
Experimental layout. (A) Overview of the historical centre of Santiago de Compostela (outlined in blue) and the location of the study site (red point). (B) Study site, inner courtyard (outlined in red), 1: Pazo de Raxoi (city council buildings), 2: Praza do Obradoiro (Obradoiro Square), 3: Cathedral of Santiago de Compostela, 4: Colexio de San Xerome (a university building). (C,D) Experimental set-up details in the inner courtyard. A: CromaLux light, B: Metal halide lamp (positive control). 1: location of the insect trap beside the CromaLux lamp, 2: location of the insect trap beside the metal halide lamp, 3: location of the insect trap in the unilluminated area. *: sheets used to prevent interference between both light systems. Aerial photographs from PNOA 2020 © CNIG. Full article ">Figure 3
Normalised spectra of the CromaLux lamp with a CCT of 3000 K (blue line) and the metal halide lamp with a CCT of 4668 K (orange line). No significant differences were found between the mean values of light intensity in luxes of both lamps in the surrounding areas where the insects were trapped. The spectral sensitivity range of insects is 330–640 nm [<a href="#B38-insects-13-01153" class="html-bibr">38</a>]. Full article ">Figure 4
Photographs of some of the insects captured. (A) Coleoptera (Latridiidae), (B) Diptera (Psychodidae), (C) Hemiptera (Cicadella viridis), (D) Hymenoptera (Chrysididae), (E) Lepidoptera, (F) Neuroptera (Chrysoperla carnea), (G) Psocoptera (Psocomorpha), (H) Thysanoptera, and (I) Trichoptera (Hydroptilidae). Full article ">Figure 5
Overlapped photographs of all sticky board traps for the three lighting systems. Full article ">Figure 6
Insect abundance and insect biodiversity captured beside the three lighting systems. Co: Coleoptera, D.: Diptera, He.: Hemiptera, Hy.: Hymenoptera, Lp.: Lepidoptera, Ne.: Neuroptera, Ps.: Psocoptera, Th.: Thysanoptera, Tr.: Trichoptera. Full article ">Figure 7
Temporal succession of insect abundance (A) and insect diversity (B) corresponding to the three lighting conditions during the five study periods (see <a href="#insects-13-01153-t001" class="html-table">Table 1</a>). The black line represents the total abundance of insects (A) and of insect morphospecies (B). The numbers in (B) indicate the Shannon–Wiener index for each time period. Full article ">

16 pages, 1658 KiB

Open AccessArticle

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

Cited by 5 | Viewed by 3643

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

Open AccessArticle

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 5 | Viewed by 2261

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

Open AccessArticle

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 10 | Viewed by 3307

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

Open AccessArticle

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 8 | Viewed by 2321

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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Survival rate of eggs and larvae (a), prepupae and pupae (b), female adults and male adults (c) of S. litura fed on different tissues of asparagus. Full article ">Figure 2
Population survival rate (lx) (a), fecundity of female adult (fxj) (b), population fecundity (mx) (c), and population maternity (lxmx) (d) of S. litura fed on different tissues of asparagus. Full article ">Figure 3
Age-stage-specific life expectancy (exj) of eggs and larvae (a), prepupae and pupae (b), female adults and male adults (c) of S. litura fed on different tissues of asparagus. Full article ">Figure 4
Age-stage-specific reproductive value (vxj) of eggs and larvae (a), prepupae and pupae (b), female adults and male adults (c) of S. litura fed on different tissues of asparagus. Full article ">Figure 5
Population projection of S. litura fed on different tissues of asparagus. Full article ">Figure 6
Population projection of each insect stage of eggs and larvae (a), prepupae and pupae (b), female adults and male adults (c) of S. litura fed on different tissues of asparagus. Full article ">Figure 7
Feeding preference of each larvae stage of S. litura between asparagus stems and leaves. Values are mean ± SE, different lowercase letters at the same investigation time indicate that the same instar larvae are significantly different between different tissues, and different capital letters indicate that the different instar larvae are significantly different between the same tissues (p < 0.05). Full article ">

12 pages, 3726 KiB

Open AccessArticle

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 2311

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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Ascodipteron guoliangi sp. nov. and its host Coelops frithii. (A). Roosting host with neosomes in each elbow pit (arrows). (B,C). Neosomes embedded in host tissue. (D,E). Neosome terminalia protruding from host tissue. (F). Blood vessels passing through the neosome. (1A: courtesy Mr. Huang Yue (Nanjing, China).) Full article ">Figure 2
Ascodipteron guoliangi sp. nov., ex. Coelops frithii, China. (A). Whole neosome (head and thorax fully withdrawn, arrow indicates direction of the head) (BFU-2434, neosome holotype). (B–D). Head and thorax; dorsal view (BFU–2437, neosome paratype) (B), lateral view (C), and ventral view (D). Abbreviations: ant—antenna; fr—frons; and lv—lateral vertex. Scale bars: A = 500 μm; B,C = 200 μm. Full article ">Figure 3
Ascodipteron guoliangi sp. nov., ex. Coelops. frithii, China (BFU-2437, neosome paratype). (A). Thorax, lateral view. (B). Labial theca, dorsal view. (C). Labial theca, ventral view. Abbreviations: a.s.—anterior thoracic spiracle; cx1—coxa 1; g—gena; hp—hypopleuron; lv—lateral vertex; ms—mesopleuron; pt—pteropleuron; s.w.—stump of wing; ster—sternopleuron; t.1—trochanter 1. Scale bars: A–C = 200 μm. Full article ">Figure 4
Ascodipteron guoliangi sp. nov., ex. Coelops. frithii, China (BFU-2437, neosome paratype). (A). Frons and lateral vertex. (B). Thorax, ventral view. (C). Terminalia, posterior view. (D,E). Terminalia, ventral view (D) and dorsal view (E), indicating five terminal annular rows of setae (R4 absent, R5 only in ventral view). Abbreviations: cerc—cercus; cx1–3—coxa 1–3; DSS—dorsal spiracular setae; MSS—medial spiracular setae; R1–5—abdominal setae arranged roughly into annular rows comprised of variable types of setae, R1 the proximal and R5 the distal row; sp5–sp7—spiracles 5–7; t.1–3—trochanter 1–3; vo—vaginal orifice; VSS—ventral spiracular setae. Scale bars: A,B = 100 μm; C,D = 200 μm. Full article ">Figure 5
Habitat of Coelops frithii. (A). The roadside slope with the two openings (white arrows) to the cave (a former bomb shelter). (B). The opening to the right branch of the cave. (C). The deepest part of the right cave. Full article ">

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

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