Insects

13 pages, 822 KiB

Open AccessArticle

Urban Individuals of Three Rove Beetle Species Are Not More Exploratory or Risk-Taking Than Rural Conspecifics

by Tibor Magura, Roland Horváth, Szabolcs Mizser, Mária Tóth, Dávid D. Nagy, Réka Csicsek, Emőke Balla and Gábor L. Lövei

Insects 2022, 13(8), 757; https://doi.org/10.3390/insects13080757 - 22 Aug 2022

Cited by 3 | Viewed by 1499

Abstract

Urbanization is creating changes in environmental and habitat conditions, as well as creating disturbance and threats to urban-associated species. Some traits, such as high exploratory and risk-taking behavior, are beneficial to allow colonization of urban habitats and coping with urbanization-derived pressures. In this [...] Read more.

Urbanization is creating changes in environmental and habitat conditions, as well as creating disturbance and threats to urban-associated species. Some traits, such as high exploratory and risk-taking behavior, are beneficial to allow colonization of urban habitats and coping with urbanization-derived pressures. In this study the exploratory and risk-taking behavior of rural and urban individuals of three forest-associated rove beetle species were tested during their main reproductive period by five frequently used behavioral measures. Individuals of all studied species were similarly ranked by all behavioral measures, indicating that the studied rove beetles responded consistently in the different contexts. However, the behavior of beetles was consistent over time for all/most studied species only by using two measures of exploratory behavior. These provide evidence for the existence of the exploratory dimension of personality in rove beetles. We found a higher exploratory behavior in males than females in Ocypus nitens which can be explained by the active searching of males for mating partners. There were no urbanization-related differences in the exploratory behavior of individuals, suggesting that behavioral changes (being more exploratory) may not yield additional fitness benefits in these rove beetle species with good dispersal capacity. Full article

(This article belongs to the Section Insect Ecology, Diversity and Conservation)

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15 pages, 1163 KiB

Open AccessReview

From Mosquito Ovaries to Ecdysone; from Ecdysone to Wolbachia: One Woman’s Career in Insect Biology

by Ann M. Fallon

Insects 2022, 13(8), 756; https://doi.org/10.3390/insects13080756 - 22 Aug 2022

Cited by 2 | Viewed by 2189

Abstract

In anautogenous mosquitoes, synchronous development of terminal ovarian follicles after a blood meal provides an important model for studies on insect reproduction. Removal and implantation of ovaries, in vitro culture of dissected tissues and immunological assays for vitellogenin synthesis by the fat body [...] Read more.

In anautogenous mosquitoes, synchronous development of terminal ovarian follicles after a blood meal provides an important model for studies on insect reproduction. Removal and implantation of ovaries, in vitro culture of dissected tissues and immunological assays for vitellogenin synthesis by the fat body showed that the Aedes aegypti (L.) (Diptera, Culicidae) mosquito ovary produces a factor essential for egg production. The discovery that the ovarian factor was the insect steroid hormone, ecdysone, provided a model for co-option of the larval hormones as reproductive hormones in adult insects. In later work on cultured mosquito cells, ecdysone was shown to arrest the cell cycle, resulting in an accumulation of diploid cells in G1, prior to initiation of DNA synthesis. Some mosquito species, such as Culex pipiens L. (Diptera, Culicidae), harbor the obligate intracellular bacterium, Wolbachia pipientis Hertig (Rickettsiales, Anaplasmataceae), in their reproductive tissues. When maintained in mosquito cell lines, Wolbachia abundance increases in ecdysone-arrested cells. This observation facilitated the recovery of high levels of Wolbachia from cultured cells for microinjection and genetic manipulation. In female Culex pipiens, it will be of interest to explore how hormonal cues that support initiation and progression of the vitellogenic cycle influence Wolbachia replication and transmission to subsequent generations via infected eggs. Full article

(This article belongs to the Special Issue Contributions of Women in Insect Science)

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12 pages, 1924 KiB

Open AccessFeature PaperArticle

Functional Role of AsAP in the Reproduction of Adelphocoris suturalis (Hemiptera: Miridae)

by Shidong Qin, Bangqin Zhu, Xingxing Huang, J. Joe Hull, Lizhen Chen and Jing Luo

Insects 2022, 13(8), 755; https://doi.org/10.3390/insects13080755 - 22 Aug 2022

Cited by 2 | Viewed by 1229

Abstract

Adelphocoris suturalis Jakovlev (Hemiptera: Miridae) is an omnivorous agricultural pest that has severe economic impacts on a diverse range of agricultural crops. Although the targeted disruption of reproductive development among insects has been proposed as a novel control strategy for pest species, the [...] Read more.

Adelphocoris suturalis Jakovlev (Hemiptera: Miridae) is an omnivorous agricultural pest that has severe economic impacts on a diverse range of agricultural crops. Although the targeted disruption of reproductive development among insects has been proposed as a novel control strategy for pest species, the current understanding of the physiology and molecular mechanisms of A. suturalis reproduction is very limited. In this study, we isolated a putative A. suturalisaspartic protease (AsAP) gene that is highly expressed in the fat body and ovaries of sexually mature females. The double-stranded RNA (dsRNA)-mediated knockdown of AsAP suppressed ovarian development and negatively impacted female fertility, which suggested that it plays an essential role in A. suturalis reproduction. The results of this study could help to expand our understanding of A. suturalis reproductive development and have the potential to facilitate the development of effective strategies for the better control of this pest species. Full article

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16 pages, 3095 KiB

Open AccessArticle

The Differential Effects of Tuta absoluta Infestations on the Physiological Processes and Growth of Tomato, Potato, and Eggplant

by Lindiwe Mahlangu, Phumzile Sibisi, Robert S. Nofemela, Titus Ngmenzuma and Khayalethu Ntushelo

Insects 2022, 13(8), 754; https://doi.org/10.3390/insects13080754 - 22 Aug 2022

Cited by 1 | Viewed by 2347

Abstract

Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) is a destructive insect pest toward crops and belongs to the Solanaceae family. Since it was first recorded in South Africa in 2016, the pest has spread extensively and caused tremendous damage to field [...] Read more.

Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) is a destructive insect pest toward crops and belongs to the Solanaceae family. Since it was first recorded in South Africa in 2016, the pest has spread extensively and caused tremendous damage to field and tunnel-grown tomato crops. This study aimed to investigate how T. absoluta affects the growth and physiology of three Solanaceae plant species: tomato, potato, and eggplant. These three crops were infested with L1 instar larvae, and their growth and physiology were assessed during insect feeding. The damage to the infested tomato host plant was severe, with T. absoluta destroying 100% of the plants. The tomato plants were distorted 15 days after infestation, that is, before the fruit set. For potato, the defoliation was moderate, but the infested plants produced fewer tubers compared to the uninfested host plants. Eggplant had fewer visible signs of feeding, resulting in no significant difference between the infested and uninfested host plants in terms of growth and physiological functions. Infested tomato and potato plants had stagnant growth, fewer and damaged leaves, a reduced chlorophyll content, a reduced photosynthesis rate, a poor transpiration rate, poor water conductance, and poor intercellular carbon dioxide concentrations. This study closes the knowledge gap on the morphological (growth) and physiological responses of different Solanaceae species to T. absoluta infestation, and it also demonstrates the differential risk of T. absoluta infestations in the production of tomato, potato, and eggplant. Full article

(This article belongs to the Collection Plant Responses to Insect Herbivores)

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14 pages, 2313 KiB

Open AccessArticle

Fruit Fly in a Challenging Environment: Impact of Short-Term Temperature Stress on the Survival, Development, Reproduction, and Trehalose Metabolism of Bactrocera dorsalis (Diptera: Tephritidae)

by Chun Yu, Runa Zhao, Wei Zhou, Yingna Pan, Hui Tian, Zhengyan Yin and Wenlong Chen

Insects 2022, 13(8), 753; https://doi.org/10.3390/insects13080753 - 22 Aug 2022

Cited by 7 | Viewed by 2428

Abstract

An understanding of physiological damage and population development caused by uncomfortable temperature plays an important role in pest control. In order to clarify the adaptability of different temperatures and physiological response mechanism of B. dorsalis, we focused on the adaptation ability of [...] Read more.

An understanding of physiological damage and population development caused by uncomfortable temperature plays an important role in pest control. In order to clarify the adaptability of different temperatures and physiological response mechanism of B. dorsalis, we focused on the adaptation ability of this pest to environmental stress from physiological and ecological viewpoints. In this study, we explored the relationship between population parameters and glucose, glycogen, trehalose, and trehalose-6-phosphate synthase responses to high and low temperatures. Compared with the control group, temperature stress delayed the development duration of all stages, and the survival rates and longevity decreased gradually as temperature decreased to 0 °C and increased to 36 °C. Furthermore, with low temperature decrease from 10 °C to 0 °C, the average fecundity per female increased at 10 °C but decreased later. Reproduction of the species was negatively affected during high-temperature stresses, reaching the lowest value at 36 °C. In addition to significantly affecting biological characteristics, temperature stress influenced physiological changes of B. dorsalis in cold and heat tolerance. When temperature deviated significantly from the norm, the levels of substances associated with temperature resistance were altered: glucose, trehalose, and TPS levels increased, but glycogen levels decreased. These results suggest that temperature stresses exert a detrimental effect on the populations’ survival, but the metabolism of trehalose and glycogen may enhance the pest’s temperature resistance. Full article

(This article belongs to the Topic Integrated Pest Management of Crops)

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14 pages, 3547 KiB

Open AccessArticle

One Species, Hundreds of Subspecies? New Insight into the Intraspecific Classification of the Old World Swallowtail (Papilio machaon Linnaeus, 1758) Based on Two Mitochondrial DNA Markers

by Paweł J. Domagała and Jerzy A. Lis

Insects 2022, 13(8), 752; https://doi.org/10.3390/insects13080752 - 21 Aug 2022

Cited by 1 | Viewed by 2091

Abstract

The Old World swallowtail Papilio machaon Linnaeus, 1758 is one of the most well-known and most characteristic members of the family Papilionidae. Over the past two centuries, the butterfly has been the subject of many studies. P. machaon is characterised by a tendency [...] Read more.

The Old World swallowtail Papilio machaon Linnaeus, 1758 is one of the most well-known and most characteristic members of the family Papilionidae. Over the past two centuries, the butterfly has been the subject of many studies. P. machaon is characterised by a tendency to change the wing colour pattern. In turn, due to the great interest of collectors and amateur entomologists, these studies have been converted into the description of over 100 colour forms, aberrations and subspecies. In this study, mitochondrial DNA (mtDNA), 16S rDNA and cytochrome b sequences were used to examine the correlation between the intraspecific classification and genetic structure of P. machaon. The study used 87 specimens from 59 different localities covering the geographic distribution of this species in the Palaearctic. The phylogenetic relationships within and between the Old World swallowtail subspecies showed that the intraspecific classification proposed by various authors does not correlate with the variability in mitochondrial DNA sequences. In addition, populations occurring at the species distribution borders in the Palaearctic Region (i.e., Japan, Kamchatka, Morocco and Sakhalin) are genetically distinct from other species. Full article

(This article belongs to the Section Insect Systematics, Phylogeny and Evolution)

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17 pages, 981 KiB

Open AccessArticle

Seasonal Dynamics of Fruit Flies (Diptera: Drosophilidae) in Forests of the European Russia

by Nikolai G. Gornostaev, Alexander B. Ruchin, Mikhail N. Esin and Aleksei M. Kulikov

Insects 2022, 13(8), 751; https://doi.org/10.3390/insects13080751 - 20 Aug 2022

Cited by 5 | Viewed by 2232

Abstract

(1) Background: Seasonal dynamics of the abundance and species diversity of various insect groups is of great importance for understanding their life cycles; (2) Methods: In our study, Drosophilidae species and their seasonal changes in Mordovia State Nature Reserve were explored. We collected [...] Read more.

(1) Background: Seasonal dynamics of the abundance and species diversity of various insect groups is of great importance for understanding their life cycles; (2) Methods: In our study, Drosophilidae species and their seasonal changes in Mordovia State Nature Reserve were explored. We collected the flies by crown fermental traps in five types of forests (birch, aspen, linden, pine and oak) since May to October in 2019. (3) Results: A total of 4725 individuals belonging to 9 genera and 30 species of drosophilid flies were identified, among them 15 species in 3 genera are new to the Republic of Mordovia. Drosophila obscura and D. histrio were the most abundant species in traps, the other mass species are D. kuntzei, D. testacea, D. phalerata, S. rufifrons, D. bifasciata, A. semivirgo, and L. quinquemaculata. (4) Conclusions: We found three groups of mass species with significant correlation of seasonal dynamics, e.g., D.obscura and D. bifasciata; D. histrio, D. kuntzei, D. phalerata, and D. testacea, and, finally, A. semivirgo and S. rufifrons. Apparently, the similarity observed in the seasonal dynamics of these drosophilid species is influenced at a high degree by their food preferences and rearing sites. Full article

(This article belongs to the Collection Advances in Diptera Biology)

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14 pages, 2671 KiB

Open AccessArticle

Evaluation of Spatial Distribution of Three Major Leptocorisa (Hemiptera: Alydidae) Pests Using MaxEnt Model

by Jeong Ho Hwang, Se-Hyun Kim, Sunhee Yoon, Sunghoon Jung, Dong Hee Kim and Wang-Hee Lee

Insects 2022, 13(8), 750; https://doi.org/10.3390/insects13080750 - 20 Aug 2022

Cited by 3 | Viewed by 2360

Abstract

We targeted three major Leptocorisa species (L. chinensis, L. acuta, and L. oratoria) and evaluated their potential distributions using MaxEnt. The results showed that most Asian countries and northern Australia would be suitable for at least one of these [...] Read more.

We targeted three major Leptocorisa species (L. chinensis, L. acuta, and L. oratoria) and evaluated their potential distributions using MaxEnt. The results showed that most Asian countries and northern Australia would be suitable for at least one of these pest species, and climate change will expand their habitat northward. All of the developed models were evaluated to be excellent with AUC, TSS, and OR10%. Most of the recorded regions of the Leptocorisa species are consistent with the result of potential distributions predicted in this study. The results confirmed that the minimum temperature of the coldest month mainly influences the three Leptocorisa species distributions. The potential distributions of the three species cover major rice cultivation areas regardless of climate change, suggesting that it would be necessary to establish a sustainable control strategy for the pests. Full article

(This article belongs to the Collection Hemiptera: Ecology, Physiology, and Economic Importance)

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29 pages, 9246 KiB

Open AccessArticle

New Records and Updated Checklist of the Pentatomoidea (Hemiptera: Heteroptera) of Greece

by Antonios Tsagkarakis, Zoi Thanou, Aikaterini Chaldeou, Ioanna Moschou, Argyro Kalaitzaki and Sakis Drosopoulos

Insects 2022, 13(8), 749; https://doi.org/10.3390/insects13080749 - 19 Aug 2022

Cited by 2 | Viewed by 1555

Abstract

Eight species of the superfamily Pentatomoidea are recorded from Greece for the first time: Aelia germari Küster 1852, Eurygaster hottentotta (Fabricius 1775), Eysarcoris aeneus (Scopoli 1763), Neottiglossa lineolata (Herrich-Schaeffer 1830), Neottiglossa pusilla (Gallen 1789), Picromerus bidens (Linnaeus 1758), Podops (Podops) inunctus (Fabricius 1775) [...] Read more.

Eight species of the superfamily Pentatomoidea are recorded from Greece for the first time: Aelia germari Küster 1852, Eurygaster hottentotta (Fabricius 1775), Eysarcoris aeneus (Scopoli 1763), Neottiglossa lineolata (Herrich-Schaeffer 1830), Neottiglossa pusilla (Gallen 1789), Picromerus bidens (Linnaeus 1758), Podops (Podops) inunctus (Fabricius 1775) and Tarisa pallescens (Jakovlev 1871). A complete updated species checklist with distributional data notes for all the new species for Greece are provided. Full article

(This article belongs to the Collection Hemiptera: Ecology, Physiology, and Economic Importance)

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13 pages, 1836 KiB

Open AccessArticle

A Bombyx mori Infection Model for Screening Antibiotics against Staphylococcus epidermidis

by Aurora Montali, Francesca Berini, Alessio Saviane, Silvia Cappellozza, Flavia Marinelli and Gianluca Tettamanti

Insects 2022, 13(8), 748; https://doi.org/10.3390/insects13080748 - 19 Aug 2022

Cited by 5 | Viewed by 1761

Abstract

The increasing number of microorganisms that are resistant to antibiotics is prompting the development of new antimicrobial compounds and strategies to fight bacterial infections. The use of insects to screen and test new drugs is increasingly considered a promising tool to accelerate the [...] Read more.

The increasing number of microorganisms that are resistant to antibiotics is prompting the development of new antimicrobial compounds and strategies to fight bacterial infections. The use of insects to screen and test new drugs is increasingly considered a promising tool to accelerate the discovery phase and limit the use of mammalians. In this study, we used for the first time the silkworm, Bombyx mori, as an in vivo infection model to test the efficacy of three glycopeptide antibiotics (GPAs), against the nosocomial pathogen Staphylococcus epidermidis. To reproduce the human physiological temperature, the bacterial infection was performed at 37 °C and it was monitored over time by evaluating the survival rate of the larvae, as well the response of immunological markers (i.e., activity of hemocytes, activation of the prophenoloxidase system, and lysozyme activity). All the three GPAs tested (vancomycin, teicoplanin, and dalbavancin) were effective in curing infected larvae, significantly reducing their mortality and blocking the activation of the immune system. These results corroborate the use of this silkworm infection model for the in vivo studies of antimicrobial molecules active against staphylococci. Full article

(This article belongs to the Special Issue Silkworm and Silk: Traditional and Innovative Applications)

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25 pages, 2837 KiB

Open AccessArticle

Interactive Effects of Temperature and Plant Host on the Development Parameters of Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae)

by Rameswor Maharjan, Jeongjoon Ahn and Hwijong Yi

Insects 2022, 13(8), 747; https://doi.org/10.3390/insects13080747 - 19 Aug 2022

Cited by 2 | Viewed by 1548

Abstract

This study investigated the effects of different temperatures (15, 20, 25, 27, 30, 35, and 40 °C) on the development rate of Spodoptera exigua (Hübner) eggs, larvae, pupae, and total immatures on plant hosts (soybean, maize, potato, and green pea). The eggs of [...] Read more.

This study investigated the effects of different temperatures (15, 20, 25, 27, 30, 35, and 40 °C) on the development rate of Spodoptera exigua (Hübner) eggs, larvae, pupae, and total immatures on plant hosts (soybean, maize, potato, and green pea). The eggs of S. exigua developed successfully at all the tested temperatures, except at 40 °C. The total developmental time (egg-adult) decreased with an increasing temperature from 15 to 35 °C on plant hosts. Stage-specific parameters such as the lower threshold temperature (TH) were determined using linear and nonlinear models (Sharpe-Schoolfield-Ikemoto [SSI]). The lower developmental threshold (LDT) and thermal constant (K) were determined using a linear model. The LDT and K for the total immature stage had respective values of 11.9 °C and 397.27° -day (DD) on soybean, 11.6 °C and 458.34° -day (DD) on maize, 11.2 °C and 446.23° -day (DD) on potato, 10.7 °C and 439.75° -day (DD) on green pea, and 12.2 °C and 355.82° -day (DD) on the artificial diet. The emergence frequency of adult S. exigua over the full range of constant temperatures was simulated using nonlinear developmental rate functions and the Weibull function. This study predicted the spring emergence date in the first to second weeks of June, with approximately five generations for plant hosts. The interaction of temperature and plant host also influenced the development and longevity of the adults. Overall, the findings of this study may be useful for predicting the number of generations, occurrence, population dynamics in crop fields, and management of S. exigua. Full article

(This article belongs to the Topic Integrated Pest Management of Crops)

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7 pages, 1502 KiB

Open AccessCommunication

Discovery of the Genus Anapleus Horn, 1873 from Cretaceous Kachin Amber (Coleoptera: Histeridae)

by Rixin Jiang, Michael S. Caterino and Xiangsheng Chen

Insects 2022, 13(8), 746; https://doi.org/10.3390/insects13080746 - 19 Aug 2022

Cited by 3 | Viewed by 1391

Abstract

For the first time, an extant histerid genus Anapleus Horn, 1873 is described from a specimen found in mid-Cretaceous Kachin amber. Anapleus kachinensis sp. nov. Although the genus Anapleus has not been precisely defined by synapomorphies, the new species shares numerous features with [...] Read more.

For the first time, an extant histerid genus Anapleus Horn, 1873 is described from a specimen found in mid-Cretaceous Kachin amber. Anapleus kachinensis sp. nov. Although the genus Anapleus has not been precisely defined by synapomorphies, the new species shares numerous features with extant species while differing in comparatively few external characteristics. Anapleus kachinensis represents the first record of an extant histerid genus from Cretaceous deposits and provides further evidence of the ancient origin of the genus. Full article

(This article belongs to the Special Issue Beetle Diversity)

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21 pages, 7606 KiB

Open AccessArticle

Pyrethroids in an AlphaFold2 Model of the Insect Sodium Channel

by Boris S. Zhorov and Ke Dong

Insects 2022, 13(8), 745; https://doi.org/10.3390/insects13080745 - 18 Aug 2022

Cited by 6 | Viewed by 2295

Abstract

Pyrethroid insecticides stabilize the open state of insect sodium channels. Previous mutational, electrophysiological, and computational analyses led to the development of homology models predicting two pyrethroid receptor sites, PyR1 and PyR2. Many of the naturally occurring sodium channel mutations, which confer knockdown resistance [...] Read more.

Pyrethroid insecticides stabilize the open state of insect sodium channels. Previous mutational, electrophysiological, and computational analyses led to the development of homology models predicting two pyrethroid receptor sites, PyR1 and PyR2. Many of the naturally occurring sodium channel mutations, which confer knockdown resistance (kdr) to pyrethroids, are located within or close to these receptor sites, indicating that these mutations impair pyrethroid binding. However, the mechanism of the state-dependent action of pyrethroids and the mechanisms by which kdr mutations beyond the receptor sites confer resistance remain unclear. Recent advances in protein structure prediction using the AlphaFold2 (AF2) neural network allowed us to generate a new model of the mosquito sodium channel AaNav1-1, with the activated voltage-sensing domains (VSMs) and the presumably inactivated pore domain (PM). We further employed Monte Carlo energy minimizations to open PM and deactivate VSM-I and VSM-II to generate additional models. The docking of a Type II pyrethroid deltamethrin in the models predicted its interactions with many known pyrethroid-sensing residues in the PyR1 and PyR2 sites and revealed ligand-channel interactions that stabilized the open PM and activated VSMs. Our study confirms the predicted two pyrethroid receptor sites, explains the state-dependent action of pyrethroids, and proposes the mechanisms of the allosteric effects of various kdr mutations on pyrethroid action. The AF2-based models may assist in the structure-based design of new insecticides. Full article

(This article belongs to the Special Issue The Evolution of Pesticide Resistance)

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18 pages, 1523 KiB

Open AccessArticle

Where Does Honey Bee (Apis mellifera L.) Pollen Come from? A Study of Pollen Collected from Colonies at Ornamental Plant Nurseries

by Kimberly A. Stoner, Andrea Nurse, Robert W. Koethe, Maxwell S. Hatala and David M. Lehmann

Insects 2022, 13(8), 744; https://doi.org/10.3390/insects13080744 - 18 Aug 2022

Cited by 6 | Viewed by 2000

Abstract

Ornamental nursery plants are both a major agricultural industry in the U.S. and a major feature of the urban and suburban landscape. Interest in their relationship with pollinators is two-fold: the extent to which they provide a nutritional benefit to pollinators, and the [...] Read more.

Ornamental nursery plants are both a major agricultural industry in the U.S. and a major feature of the urban and suburban landscape. Interest in their relationship with pollinators is two-fold: the extent to which they provide a nutritional benefit to pollinators, and the extent to which they have the potential to harm pollinators by exposing them to pesticide residues in nectar and pollen. We identified plant genera as sources of trapped pollen collected by honey bee colonies located at commercial ornamental plant nurseries in Connecticut in 2015 and 2018 and quantified the percentage of pollen volume collected from each genus for each weekly sample over two seasons. Plant genera grown at these nurseries, particularly Rosa, Rhus, and Ilex, contributed substantially to pollen volume during weeks 23–27 of the year. Among the genera not grown in nurseries, Toxicodendron was also important during weeks 23 and 24, and Trifolium was important in both frequency and quantity throughout the season. Zea was a major component of pollen volume from weeks 28–36 in both sites, even though cropland was not over 11% of land cover at either site. Full article

(This article belongs to the Section Insect Societies and Sociality)

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14 pages, 2338 KiB

Open AccessArticle

Repellent Activity of Clove Essential Oil Volatiles and Development of Nanofiber-Based Dispensers against Pear Psyllids (Hemiptera: Psyllidae)

by Bruna Czarnobai De Jorge, Hans E. Hummel and Jürgen Gross

Insects 2022, 13(8), 743; https://doi.org/10.3390/insects13080743 - 18 Aug 2022

Cited by 5 | Viewed by 3793

Abstract

Pear psyllids are the main vectors of the pathogen ‘Candidatus Phytoplasma pyri’ causing pear decline. Based on earlier reports, we tested the behavioral activity of the major synthetic compounds of clove essential oil (eugenol, eugenyl acetate, and β-caryophyllene) against Cacopsylla pyri and [...] Read more.

Pear psyllids are the main vectors of the pathogen ‘Candidatus Phytoplasma pyri’ causing pear decline. Based on earlier reports, we tested the behavioral activity of the major synthetic compounds of clove essential oil (eugenol, eugenyl acetate, and β-caryophyllene) against Cacopsylla pyri and C. pyricola. Of six mixtures tested in olfactometer assays, a formulation consisting of three specific compounds (M6 mixture) demonstrated a repellent effect on both psyllid species. In addition, this formulation masked the odor of the host Pyrus communis cv. Williams Christ, disturbing the host finding ability of C. pyri. Electrospun fibers were produced with biocompatible polymers poly(ε-caprolactone), cellulose acetate, and solvents formic acid and acetic acid, loaded with the repellent mixture to test their efficacy as dispensers of repellents in laboratory and field. The fibers produced were repellent to C. pyri and effectively masked the odors of pear plants in olfactometer tests. In a pear orchard, we compared the captures of pear psyllids in green-colored attractive traps treated with nanofibers loaded with M6 mixture or unloaded nanofibers (blank). The result showed no differences in the captures of C. pyri between treatments. The release rates of volatiles from the fibers were evaluated weekly over 56 days. The fibers were able to entrap the major compound of the M6 mixture, eugenol, but the release rates were significantly reduced after 21 days. Our results suggest that biodegradable dispensers could be produced with electrospinning, but further improvements are necessary to use repellents as a management tool for pear psyllids in the field. Full article

(This article belongs to the Section Insect Pest and Vector Management)

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9 pages, 686 KiB

Open AccessFeature PaperArticle

Chili Pepper Jojutla Morelos (Capsicum annuum L.), CJ-2018: A Variety Resistant to Bactericera cockerelli

by Manuel Silva-Valenzuela, Reyna Isabel Rojas-Martínez and Victor M. Zúñiga-Mayo

Insects 2022, 13(8), 742; https://doi.org/10.3390/insects13080742 - 18 Aug 2022

Cited by 1 | Viewed by 1834

Abstract

Chili pepper is a vegetable of worldwide economic and gastronomic importance. The psyllid, Bactericera cockerelli, is an economically important pest in this crop, causing considerable losses in its production. Currently, the application of insecticides is the main way to control B. cockerelli [...] Read more.

Chili pepper is a vegetable of worldwide economic and gastronomic importance. The psyllid, Bactericera cockerelli, is an economically important pest in this crop, causing considerable losses in its production. Currently, the application of insecticides is the main way to control B. cockerelli. However, the use of varieties resistant to this insect is a viable alternative for its control and management. In this work, the oviposition rate, development, and survival of B. cockerelli in two native varieties of chili were evaluated. Choice and non-choice trials showed that the B. cockerelli oviposition was reduced on CJ-2018 by 92.17 and 80.18%, respectively, compared to the control. In CM-334, the insect showed a behavior similar to the control in the non-choice test, while in the choice test it laid more eggs on CM-334 compared to the control. The development and survival assay showed that only 1.33% of the eggs managed to reach the adult stage on CJ-2018. In contrast, on CM-334 the survival of B. cockerelli was similar to the control. These results suggest that CJ-2018 presented a resistance based on antixenosis and antibiosis against B. cockerelli. Full article

(This article belongs to the Special Issue Insect-Plant Interactions in Agricultural Applications)

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10 pages, 1864 KiB

Open AccessArticle

Establishment and Expansion of Harmonia axyridis Pallas (Coleoptera: Coccinellidae) in Urban Green Areas in the Iberian Peninsula: From 2015 to 2021

by Roberto Meseguer, Belén Lumbierres and Xavier Pons

Insects 2022, 13(8), 741; https://doi.org/10.3390/insects13080741 - 17 Aug 2022

Cited by 2 | Viewed by 1207

Abstract

In the Western Palearctic region, Harmonia axyridis (Coleoptera: Coccinellidae) is mainly established in urban areas. In this study, we update its occurrence in urban areas of the Iberian Peninsula and determine its expansion after 2014. Changes in the ladybird species assemblage are also [...] Read more.

In the Western Palearctic region, Harmonia axyridis (Coleoptera: Coccinellidae) is mainly established in urban areas. In this study, we update its occurrence in urban areas of the Iberian Peninsula and determine its expansion after 2014. Changes in the ladybird species assemblage are also evaluated. We compile information about the records of H. axyridis in Spain from 2015 to 2021. In addition, we sample different locations to determine the relative abundances of the species composing the aphidophagous ladybird complex. The expansion of H. axyridis mainly occurred in Catalonia (Iberian Peninsula), where it is possible to identify two clear areas: one that has already been invaded and another that has not yet been invaded. Harmonia axyridis became the dominant species in the invaded area two years after it was first identified. This dominance is clearly shown on Liriodendron tulipifera and Tilia platyphyllos, where it accounted for more than 75% of the total collected individuals in the last year of the study. In the not-yet invaded area, Adalia bipunctata overcame Oenopia conglobata and became the prevalent species from 2020 onwards, likely due to its regular releases for aphid biocontrol. This study reveals that changes in ladybird species assemblages may not only be caused by invasive species, but also by biological control practices. Full article

(This article belongs to the Special Issue Integrated Pest Management of Arthropods in Urban Green Spaces)

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16 pages, 1821 KiB

Open AccessArticle

Intestinal Bacterial Diversity and Functional Analysis of Three Lepidopteran Corn Ear Worm Larvae

by Jiqiang Zhang, Shanshan Gao, Fangqiang Zheng and Ningxin Wang

Insects 2022, 13(8), 740; https://doi.org/10.3390/insects13080740 - 17 Aug 2022

Cited by 4 | Viewed by 1569

Abstract

Insects, as the most abundant animal group on earth, and their symbionts help their hosts to adapt to various environments. Conogethes punctiferalis, Ostrinia furnacalis and Helicoverpa armigera are three main pests co-occurring in the ear stage of corn, which significantly affect the [...] Read more.

Insects, as the most abundant animal group on earth, and their symbionts help their hosts to adapt to various environments. Conogethes punctiferalis, Ostrinia furnacalis and Helicoverpa armigera are three main pests co-occurring in the ear stage of corn, which significantly affect the yield and quality of corn. The purpose of this study was to compare the diversity and function of the intestinal bacteria of the three co-occurring lepidopteran pests, C. punctiferalis, O. furnacalis and H. armigera, and to explore the reason of their prevalence from the microbiota’s view. Our results showed the difference of diversity and abundance of the gut bacteria of three co-occurring lepidopteran pests at the ear stage. Proteobacteria and Firmicutes were the dominant phyla, and the Enterobacteriaceae and Enterococcaceae were the dominant families in the three pests. Compared with the other two pests, Bacteroidetes was found much more in C. punctiferalis. In addition, C. punctiferalis showed more correlation and similarity in bacteria composition with corn endophytic bacteria, as well as had obvious advantages in metabolic, environmental information processing, cellular processes and organic systems function pathways. Our findings may provide insight into the prevalence of corn earworm larvae from the perspective of gut microbiota and function prediction. Full article

(This article belongs to the Section Insect Pest and Vector Management)

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17 pages, 2218 KiB

Open AccessArticle

Development of RNAi Methods for the Mormon Cricket, Anabrus simplex (Orthoptera: Tettigoniidae)

by Toan Hoang, Bert Foquet, Seema Rana, Drew W. Little, Derek A. Woller, Gregory A. Sword and Hojun Song

Insects 2022, 13(8), 739; https://doi.org/10.3390/insects13080739 - 17 Aug 2022

Cited by 3 | Viewed by 2032

Abstract

Mormon crickets are a major rangeland pest in the western United States and are currently managed by targeted applications of non-specific chemical insecticides, which can potentially have negative effects on the environment. In this study, we took the first steps toward developing RNAi [...] Read more.

Mormon crickets are a major rangeland pest in the western United States and are currently managed by targeted applications of non-specific chemical insecticides, which can potentially have negative effects on the environment. In this study, we took the first steps toward developing RNAi methods for Mormon crickets as a potential alternative to traditional broad-spectrum insecticides. To design an effective RNAi-based insecticide, we first generated a de novo transcriptome for the Mormon cricket and developed dsRNAs that could silence the expression of seven housekeeping genes. We then characterized the RNAi efficiencies and time-course of knockdown using these dsRNAs, and assessed their ability to induce mortality. We have demonstrated that it is possible to elicit RNAi responses in the Mormon cricket by injection, but knockdown efficiencies and the time course of RNAi response varied according to target genes and tissue types. We also show that one of the reasons for the poor knockdown efficiencies could be the presence of dsRNA-degrading enzymes in the hemolymph. RNAi silencing is possible in Mormon cricket, but more work needs to be done before it can be effectively used as a population management method. Full article

(This article belongs to the Section Insect Molecular Biology and Genomics)

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17 pages, 2153 KiB

Open AccessArticle

Relationship between Acylsugars and Leaf Trichomes: Mediators of Pest Resistance in Tomato

by Renato Barros de Lima Filho, Juliano Tadeu Vilela Resende, João Ronaldo Freitas de Oliveira, Cristiane Nardi, Paulo Roberto Silva, Caroline Rech, Luiz Vitor Barbosa Oliveira, Maurício Ursi Ventura and André Luiz Biscaia Ribeiro Silva

Insects 2022, 13(8), 738; https://doi.org/10.3390/insects13080738 - 17 Aug 2022

Cited by 1 | Viewed by 1479

Abstract

Tomato plants are highly susceptible to pests. Among the control methods, genetic improvement with introgression of resistance genes from wild accessions into commercial tomato lines is the best alternative for an integrated pest management (IPM). Thus, the objective of this study was to [...] Read more.

Tomato plants are highly susceptible to pests. Among the control methods, genetic improvement with introgression of resistance genes from wild accessions into commercial tomato lines is the best alternative for an integrated pest management (IPM). Thus, the objective of this study was to select tomato genotypes in advanced populations (F₂BC₃), with higher levels of acylsugar content, greater recurrent parent genome recovery, and resistance to Tetranychus urticae and Bemisia tabaci inherited from Solanum pennellii. For pest resistance, bioassays were assessed: nine high-acylsugar genotypes, four low-acylsugar genotypes, and the parents, Solanum lycopersicum or ‘Redenção’, and Solanum pennellii LA-716. Glandular and non-glandular trichomes were quantified. A negative correlation was measured between acylsugar content in the leaflets and pest behavior. Pest resistance was found in the selected F₂BC₃ genotypes with high-acylsugar content, indicating that this allelochemical was efficient in controlling the arthropod pests. Full article

(This article belongs to the Topic Integrated Pest Management of Crops)

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16 pages, 788 KiB

Open AccessArticle

Effect of Wolbachia Infection and Adult Food on the Sexual Signaling of Males of the Mediterranean Fruit Fly Ceratitis capitata

by Georgios A. Kyritsis, Panagiota Koskinioti, Kostas Bourtzis and Nikos T. Papadopoulos

Insects 2022, 13(8), 737; https://doi.org/10.3390/insects13080737 - 17 Aug 2022

Cited by 3 | Viewed by 2481

Abstract

Sexual signaling is a fundamental component of sexual behavior of Ceratitis capitata that highly determines males’ mating success. Nutritional status and age are dominant factors known to affect males’ signaling performance and define the female decision to accept a male as a sexual [...] Read more.

Sexual signaling is a fundamental component of sexual behavior of Ceratitis capitata that highly determines males’ mating success. Nutritional status and age are dominant factors known to affect males’ signaling performance and define the female decision to accept a male as a sexual partner. Wolbachia pipientis, a widespread endosymbiotic bacterium of insects and other arthropods, exerts several biological effects on its hosts. However, the effects of Wolbachia infection on the sexual behavior of medfly and the interaction between Wolbachia infection and adult food remain unexplored. This study was conducted to determine the effects of Wolbachia on sexual signaling of protein-fed and protein-deprived males. Our findings demonstrate that: (a) Wolbachia infection reduced male sexual signaling rates in both food regimes; (b) the negative effect of Wolbachia infection was more pronounced on protein-fed than protein-deprived males, and it was higher at younger ages, indicating that the bacterium regulates male sexual maturity; (c) Wolbachia infection alters the daily pattern of sexual signaling; and (d) protein deprivation bears significant descent on sexual signaling frequency of the uninfected males, whereas no difference was observed for the Wolbachia-infected males. The impact of our findings on the implementation of Incompatible Insect Technique (IIT) or the combined SIT/IIT towards controlling insect pests is discussed. Full article

(This article belongs to the Section Insect Physiology, Reproduction and Development)

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17 pages, 1543 KiB

Open AccessArticle

Comparative Analysis of Epicuticular Lipids in Locusta migratoria and Calliptamus italicus: A Possible Role in Susceptibility to Entomopathogenic Fungi

by Mariya D. Ganina, Maksim V. Tyurin, Ulzhalgas T. Zhumatayeva, Georgy R. Lednev, Sergey V. Morozov and Vadim Yu. Kryukov

Insects 2022, 13(8), 736; https://doi.org/10.3390/insects13080736 - 16 Aug 2022

Cited by 1 | Viewed by 1536

Abstract

Cuticular lipids protect insects from desiccation and may determine resistance to fungal pathogens. Nonetheless, the trade-off between these lipid functions is still poorly understood. The migratory locust Locusta migratoria and the Italian locust Calliptamus italicus have dissimilar hygrothermal preferences: L. migratoria inhabits areas [...] Read more.

Cuticular lipids protect insects from desiccation and may determine resistance to fungal pathogens. Nonetheless, the trade-off between these lipid functions is still poorly understood. The migratory locust Locusta migratoria and the Italian locust Calliptamus italicus have dissimilar hygrothermal preferences: L. migratoria inhabits areas near water bodies with a reed bed, and C. italicus exploits a wide range of habitats and prefers steppes and semideserts with the predominance of sagebrushes. This paper presents significant differences between these species’ nymphs in epicuticular lipid composition (according to gas chromatography with mass spectrometry) and in susceptibility to Metarhizium robertsii and Beauveria bassiana. The main differences in lipid composition are shifts to longer chain and branched hydrocarbons (di- and trimethylalkanes) in C. italicus compared to L. migratoria. C. italicus also has a slightly higher n-alkane content. Fatty acids showed low concentrations in the extracts, and L. migratoria has a wider range of fatty acids than C. italicus does. Susceptibility to M. robertsii and the number of conidia adhering to the cuticle proved to be significantly higher in C. italicus, although conidia germination percentages on epicuticular extracts did not differ between the species. We propose that the hydrocarbon composition of C. italicus may be an adaptation to a wide range of habitats including arid ones but may make the C. italicus cuticle more hospitable for fungi. Full article

(This article belongs to the Topic Advances in Chemical Ecology)

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13 pages, 2515 KiB

Open AccessArticle

Pharmacological Properties and Function of the PxOctβ3 Octopamine Receptor in Plutella xylostella (L.)

by Hang Zhu, Zheming Liu, Haihao Ma, Wei Zheng, Jia Liu, Yong Zhou, Yilong Man, Xiaomao Zhou and Aiping Zeng

Insects 2022, 13(8), 735; https://doi.org/10.3390/insects13080735 - 16 Aug 2022

Cited by 2 | Viewed by 1450

Abstract

The diamondback moth (Plutella xylostella) is one of the most destructive lepidopteran pests of cruciferous vegetables, and insights into regulation of its physiological processes contribute towards the development of new pesticides against it. Thus, we investigated the regulatory functions of its [...] Read more.

The diamondback moth (Plutella xylostella) is one of the most destructive lepidopteran pests of cruciferous vegetables, and insights into regulation of its physiological processes contribute towards the development of new pesticides against it. Thus, we investigated the regulatory functions of its β-adrenergic-like octopamine receptor (PxOctβ3). The open reading frame (ORF) of PxOctβ3 was phylogenetically analyzed, and the levels of expression of the receptor mRNA were determined. This ORF was also cloned and expressed in HEK-293 cells. A series of octopamine receptor agonists and antagonists were tested against PxOctβ3. We showed that the receptor is a member of the Octβ3 protein family, and an analysis using quantitative PCR showed that it was expressed at all developmental stages of P. xylostella. Octopamine activated PxOctβ3, resulting in increased levels of intracellular cAMP. Furthermore, the agonists naphazoline, clonidine, 2-phenethylamine, and amitraz activated the PxOctβ3 receptor, and naphazoline was the most effective. Only metoclopramide and mianserin had significant antagonistic effects on PxOctβ3, whereas yohimbine, phentolamine, and chlorpromazine lacked obvious antagonistic effects. The injection of double-stranded RNA in an RNA interference assay indicated that PxOctβ3 regulates development in P. xylostella. This study demonstrated the pharmacological properties and functions of PxOctβ3 in P. xylostella, thus, providing a theoretical basis for the design of pesticides that target octopamine receptors. Full article

(This article belongs to the Section Insect Physiology, Reproduction and Development)

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18 pages, 1389 KiB

Open AccessEditor’s ChoiceReview

Drosophila Glue: A Promising Model for Bioadhesion

by Manon Monier and Virginie Courtier-Orgogozo

Insects 2022, 13(8), 734; https://doi.org/10.3390/insects13080734 - 16 Aug 2022

Cited by 3 | Viewed by 3238

Abstract

The glue produced by Drosophila larvae to attach themselves to a substrate for several days and resist predation until the end of metamorphosis represents an attractive model to develop new adhesives for dry environments. The adhesive properties of this interesting material have been [...] Read more.

The glue produced by Drosophila larvae to attach themselves to a substrate for several days and resist predation until the end of metamorphosis represents an attractive model to develop new adhesives for dry environments. The adhesive properties of this interesting material have been investigated recently, and it was found that it binds as well as strongly adhesive commercial tapes to various types of substrates. This glue hardens rapidly after excretion and is made of several proteins. In D. melanogaster, eight glue proteins have been identified: four are long glycosylated mucoproteins containing repeats rich in prolines, serines and threonines, and four others are shorter proteins rich in cysteines. This protein mix is produced by the salivary glands through a complex packaging process that is starting to be elucidated. Drosophila species have adapted to stick to various substrates in diverse environmental conditions and glue genes appear to evolve rapidly in terms of gene number, number of repeats and sequence of the repeat motifs. Interestingly, besides its adhesive properties, the glue may also have antimicrobial activities. We discuss future perspectives and avenues of research for the development of new bioadhesives mimicking Drosophila fly glue. Full article

(This article belongs to the Special Issue Contributions of Women in Insect Science)

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12 pages, 1322 KiB

Open AccessArticle

Evaluation of Entomopathogenic Nematodes against Red Palm Weevil, Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae)

by Gul Rehman and Muhammad Mamoon-ur-Rashid

Insects 2022, 13(8), 733; https://doi.org/10.3390/insects13080733 - 16 Aug 2022

Cited by 13 | Viewed by 2097

Abstract

Entomopathogenic nematodes play a pivotal role as biocontrol agents for different species of insect pests, including the red palm weevil. In the current investigation, the infective capabilities of four species of entomopathogenic nematodes, including Hetrerorhabditis bacteriophora, Steinernema feltiae, Steinernema glaseri, [...] Read more.

Entomopathogenic nematodes play a pivotal role as biocontrol agents for different species of insect pests, including the red palm weevil. In the current investigation, the infective capabilities of four species of entomopathogenic nematodes, including Hetrerorhabditis bacteriophora, Steinernema feltiae, Steinernema glaseri, and Steinernema carpocapsae, were evaluated against larvae, pupae, and adult red palm weevil under laboratory and field conditions. The pathogenic potential of selected nematode species was assessed based on dissection and adult emergence of weevils. Our results indicated that S. carpocapsae and H. bacteriophora, with a respective 94.68 and 92.68% infection rate, were the most effective EPN species against red palm weevil larvae. Focusing on adult emergence, the aforementioned EPNs were comparatively less pathogenic and resulted in 63.60 and 60.20% infested pupae, respectively. It is noted that adult emergence is the better option to evaluate the pathogenic potential of EPNs, compared with the dissection of insects. The S. carpocapsae was found to be most effective against the 6th instar larvae of the red palm weevil and caused 100% mortality at 240 h after treatment. On the other hand, S. glaseri and S. feltiae were found to be the least pathogenic and caused 70 and 76% mortality, respectively. All of the evaluated nematode species were found to be highly infective under field conditions. The S. carpocapsae was found to be the most pathogenic, causing 83.60% mortality of the red palm weevil. However, the tested nematodes were found most effective against larvae, followed by adult weevils, but their effect was minimal against the pupae of red palm weevils. Based on these findings, we conclude that the S. carpocapsae and H. bacteriophora could be used as a sustainable option for the efficient management of the red palm weevil. Full article

(This article belongs to the Special Issue Arthropod Interactions and Pest Management in Fruit and Vegetable Crops)

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23 pages, 7301 KiB

Open AccessArticle

Predators or Herbivores: Cockroaches of Manipulatoridae Revisited with a New Genus from Cretaceous Myanmar Amber (Dictyoptera: Blattaria: Corydioidea)

by Xinran Li and Diying Huang

Insects 2022, 13(8), 732; https://doi.org/10.3390/insects13080732 - 15 Aug 2022

Cited by 5 | Viewed by 3997

Abstract

Manipulator modificaputis Vršanský and Bechly, 2015 (Manipulatoridae, Corydioidea) is a purported predatory cockroach from Cretaceous Myanmar amber, based on a single male. It is distinctive by the nimble head, elongate pronotum and legs, and particularly by the extraordinarily long maxillary palpi. In the [...] Read more.

Manipulator modificaputis Vršanský and Bechly, 2015 (Manipulatoridae, Corydioidea) is a purported predatory cockroach from Cretaceous Myanmar amber, based on a single male. It is distinctive by the nimble head, elongate pronotum and legs, and particularly by the extraordinarily long maxillary palpi. In the present study, we redescribe Manipulator modificaputis based on six new fossils including males and females, and comment on the original description. The closely related Manipulatoides obscura gen. & sp. nov. is proposed on the basis of five fossils, including males and females. It differs from Manipulator in weaker spination of the legs, including the type-C forefemoral spination instead of the type-A of Manipulator. Some undetermined adults and nymphs are also described. We discuss the ethology of Manipulatoridae and speculate that they might feed on flowers. They are unlikely to be specialized predators since they lack necessary weaponry for capturing prey; in contrast, their unique morphotype appears to be suitable for efficient foraging and locomotion amid flowering twigs. The possibility of being kleptoparasites of the spider-web is also discussed. In addition, regenerated four-segmented tarsi are found from the new species. Full article

(This article belongs to the Special Issue Fossil Insects: From Carboniferous to Quaternary)

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14 pages, 3426 KiB

Open AccessArticle

RNAi-Mediated Silencing of Putative Halloween Gene Phantom Affects the Performance of Rice Striped Stem Borer, Chilo suppressalis

by Muhammad Faisal Shahzad, Atif Idrees, Ayesha Afzal, Jamshaid Iqbal, Ziyad Abdul Qadir, Azhar Abbas Khan, Ayat Ullah and Jun Li

Insects 2022, 13(8), 731; https://doi.org/10.3390/insects13080731 - 15 Aug 2022

Cited by 2 | Viewed by 2147

Abstract

The physiological and biochemical characterization of the “Halloween” genes has fundamental importance in the biosynthesis pathway of ecdysteroids. These genes were found to catalyze the final phases of ecdysteroid biosynthesis from dietary cholesterol to the molting hormone 20-hydroxyecdysone. We report the characterization of [...] Read more.

The physiological and biochemical characterization of the “Halloween” genes has fundamental importance in the biosynthesis pathway of ecdysteroids. These genes were found to catalyze the final phases of ecdysteroid biosynthesis from dietary cholesterol to the molting hormone 20-hydroxyecdysone. We report the characterization of the Cs-Phm in a major insect pest in agriculture, the rice striped stem borer, Chilo suppressalis (C. suppressalis). A full-length transcript of Cs-Phm was amplified with an open reading frame (ORF) of 478 amino acids through 5′ and 3′ RACE. Cs-Phm shows five insect-conserved P450 motifs: Helix-C, Helix-I, Helix-K, PERF, and heme-binding motifs. Phylogenetic analysis clearly shows high similarity to Lepidoptera and evolutionary conservation in insects. The relative spatial and temporal transcript profile shows that Cs-Phm is highly expressed in the prothoracic glands and appears throughout the larval development, but with low expression at the start of the larval instar. It seems to peak in 3–4 days and decreases again before the larvae molt. Double-stranded RNA (dsRNA) injection of Cs-Phm at the larval stage efficiently knocked down the target gene and decreased its expression level. The dsRNA-treated group showed significantly decreased ecdysteroid titers, which leads to delayed larval development and higher larval mortality. Negative effects of larval development were rescued by treating 20E in the dsRNA-treated group. Thus, in conclusion, our results suggest that Cs-Phm is functionally conserved in C. suppressalis and encodes functional CYP that contributes to the biogenesis of 20E. Full article

(This article belongs to the Special Issue Managing Invasive Insects: Good Intentions, Hard Realities)

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15 pages, 3814 KiB

Open AccessArticle

Risk Assessment of the Worldwide Expansion and Outbreak of Massicus raddei (Blessig) (Coleoptera: Cerambycidae) Based on Host Plant and Climatic Factors

by Yufan Zhang, Yingqiao Dang and Xiaoyi Wang

Insects 2022, 13(8), 730; https://doi.org/10.3390/insects13080730 - 15 Aug 2022

Cited by 1 | Viewed by 1486

Abstract

Massicus raddei (Blessig) is a serious trunk borer of oak species, currently widespread only in eastern Asia. A better understanding of the invasive potential of this borer across other distribution-free areas is further needed to prevent its invasion and outbreaks. In this study, [...] Read more.

Massicus raddei (Blessig) is a serious trunk borer of oak species, currently widespread only in eastern Asia. A better understanding of the invasive potential of this borer across other distribution-free areas is further needed to prevent its invasion and outbreaks. In this study, we mapped the current distribution of M. raddei, two susceptible hosts (Quercus mongolia and Q. liaotungensis) and all 11 host species of this borer, and then modeled their potential distributions. We comprehensively compared the current distributions and potential invasion ranges among M. raddei, susceptible hosts and all hosts to select areas at risk for the establishment of this borer. MaxEnt model predictions revealed that (1) the central and eastern US, a small area of central and western Europe, western Georgia, and central Argentina had suitable climates for M. raddei. Such highly suitable areas for this borer overlapped considerably with the current plantation and potential distributions of its hosts. Consequently, susceptible hosts and climate suitability together create the highest risk for M. raddei establishment and outbreaks, throughout central and eastern America, a small area of central Europe, western Norway and western Georgia, and (2) the broad host suitability across six continents creates a situation favorable for the colonization of this borer, further extending the spatial scale of possible infestation by M. raddei worldwide. Full article

(This article belongs to the Section Insect Pest and Vector Management)

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15 pages, 1715 KiB

Open AccessArticle

Genetic Diversity and Population Structure of Spirobolus bungii as Revealed by Mitochondrial DNA Sequences

by Runfeng Xu, Jie Chen, Yu Pan, Jiachen Wang, Lu Chen, Honghua Ruan, Yongbo Wu, Hanmei Xu, Guobing Wang and Hongyi Liu

Insects 2022, 13(8), 729; https://doi.org/10.3390/insects13080729 - 15 Aug 2022

Cited by 4 | Viewed by 1922

Abstract

Soil macrofauna, such as Spirobolus bungii, are an important component of ecosystems. However, systematic studies of the genetic diversity, population genetic structure, and the potential factors affecting the genetic differentiation of S. bungii are lacking. We performed a population genetic study of [...] Read more.

Soil macrofauna, such as Spirobolus bungii, are an important component of ecosystems. However, systematic studies of the genetic diversity, population genetic structure, and the potential factors affecting the genetic differentiation of S. bungii are lacking. We performed a population genetic study of 166 individuals from the mountains to the south of the Yangtze River, north of the Yangtze River in Nanjing city, and near Tianjin city, in order to investigate the correlations between geographical distance and genetic diversity. A total of 1182 bp of COX2 and Cytb gene sequences of mitochondrial DNA, and 700 bp of the 18S rRNA gene sequence were analyzed. There were two haplotypes and one variable site in the 18S rRNA gene, and 28 haplotypes and 78 variable sites in the COX2 and Cytb genes. In this study, the 18S rRNA gene was used for species identification, and mtDNA (concatenated sequences with Cytb and COX2) was used for population genetic analysis. Structure cluster analysis indicated that the genetic structures of the different populations of S. bungii tended to be consistent at small geographical scales. Phylogenetic trees revealed that the haplotypes were clearly divided into three branches: the area south of the Yangtze River, the area to the north of the Yangtze River in Nanjing, and the area in Tianjin. Large geographical barriers and long geographical distance significantly blocked gene flow between populations of S. bungii. Our results provide a basic theoretical basis for subsequent studies of millipede taxonomy and population genetic evolution. Full article

(This article belongs to the Topic Arthropod Biodiversity: Ecological and Functional Aspects)

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14 pages, 2720 KiB

Open AccessArticle

Characterization of Chitin Synthase A cDNA from Diaphorina citri (Hemiptera: Liviidae) and Its Response to Diflubenzuron

by Cong Zhang, Wenfeng Hu, Zhuo Yu, Xian Liu, Jing Wang, Tianrong Xin, Zhiwen Zou and Bin Xia

Insects 2022, 13(8), 728; https://doi.org/10.3390/insects13080728 - 15 Aug 2022

Cited by 2 | Viewed by 1801

Abstract

Diaphorina citri Kuwayama is the vector of HLB and one of the most common pests in citrus orchards in southern China. One of the most significant genes in D. citri’s growth and development is the chitin synthase gene. In this study, the [...] Read more.

Diaphorina citri Kuwayama is the vector of HLB and one of the most common pests in citrus orchards in southern China. One of the most significant genes in D. citri’s growth and development is the chitin synthase gene. In this study, the CHS gene (DcCHSA) of D. citri was cloned and analyzed by bioinformatics. According to RT-qPCR findings, DcCHSA was expressed at many growth processes of D. citri, with the greatest influence in the fifth-instar nymph. The molting failure rate and mortality of D. citri rose as DFB concentration increased in this research, as did the expression level of DcCHSA. Feeding on DcCHSA caused a large drop in target gene expression, affected nymph molting, caused failure or even death in freshly eclosion adults, increased mortality, and reduced the molting success rate over time. These findings showed that DcCHSA was involved in nymph to adult development and may aid in the identification of molecular targets for D. citri regulation. It provided new ideas for further control of D. citri. Full article

(This article belongs to the Section Insect Molecular Biology and Genomics)

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