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Insects, Volume 15, Issue 6 (June 2024) – 90 articles

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15 pages, 5503 KiB  
Article
Life Table Study of Liriomyza trifolii and Its Contribution to Thermotolerance: Responding to Long-Term Selection Pressure for Abamectin Resistance
by Yucheng Wang, Yawen Chang, Weirong Gong and Yuzhou Du
Insects 2024, 15(6), 462; https://doi.org/10.3390/insects15060462 - 20 Jun 2024
Viewed by 239
Abstract
Liriomyza trifolii is a significant invasive pest that targets horticultural and vegetable crops, causing large-scale outbreaks characterized by pronounced thermotolerance and insecticide resistance. This study examined the impact of long-term selection for abamectin resistance during the larval stage of L. trifolii on its [...] Read more.
Liriomyza trifolii is a significant invasive pest that targets horticultural and vegetable crops, causing large-scale outbreaks characterized by pronounced thermotolerance and insecticide resistance. This study examined the impact of long-term selection for abamectin resistance during the larval stage of L. trifolii on its population dynamics and thermal tolerance. We conducted a comprehensive comparison between the abamectin-resistant strain (AB-R) and the susceptible strain (S), including age-stage, two-sex life table analysis, thermal preference (Tpref), critical thermal maximum (CTmax), heat knockdown times (HKDTs), eclosion and survival rates, and LtHsp expression under heat stress. Our results showed that while selection for abamectin resistance was detrimental to survival and reproduction, it activated self-defense mechanisms and rapid adaptive adjustments and conferred modest thermal tolerance, which suggests a dual nature of insecticide effects. The AB-R strain exhibited significantly higher thermal preference and CTmax values, along with a longer HKDT and improved survival. Additionally, there was a significant upregulation of LtHsp expression in the AB-R strain compared to the S strain. These findings indicate that the evolution of thermal adaptation was accompanied by abamectin resistance development, emphasizing the necessity of considering temperature effects when applying chemical control. Our study provides valuable insights into how physiological acclimation may help mitigate the toxic effects of insecticides and illustrate how insects respond to multiple environmental pressures. Full article
(This article belongs to the Section Insect Physiology, Reproduction and Development)
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15 pages, 1898 KiB  
Article
The P450-Monooxygenase Activity and CYP6D1 Expression in the Chlorfenapyr-Resistant Strain of Musca domestica L.
by Kseniya Krestonoshina, Anastasia Melnichuk, Anna Kinareikina, Kseniya Maslakova, Liana Yangirova and Elena Silivanova
Insects 2024, 15(6), 461; https://doi.org/10.3390/insects15060461 - 20 Jun 2024
Viewed by 283
Abstract
The house fly Musca domestica L. is one of the most common insects of veterinary and medical importance worldwide; its ability to develop resistance to a large number of insecticides is well known. Many studies support the involvement of cytochrome P-450-dependent monooxygenases (P450) [...] Read more.
The house fly Musca domestica L. is one of the most common insects of veterinary and medical importance worldwide; its ability to develop resistance to a large number of insecticides is well known. Many studies support the involvement of cytochrome P-450-dependent monooxygenases (P450) in the development of resistance to pyrethroids, neonicotinoids, carbamates, and organophosphates among insects. In this paper, the monooxygenase activity and expression level of CYP6D1 were studied for the first time in a chlorfenapyr-resistant strain of house fly. Our studies demonstrated that P450 activity in adults of the susceptible strain (Lab TY) and chlorfenapyr-resistant strain (ChlA) was 1.56–4.05-fold higher than that in larvae. In females of the Lab TY and ChlA strains, this activity was 1.53- and 1.57-fold higher, respectively (p < 0.05), than that in males, and in contrast, the expression level of CYP6D1 was 21- and 8-fold lower, respectively. The monooxygenase activity did not vary between larvae of the susceptible strain Lab TY and the chlorfenapyr-resistant strain ChlA. Activity in females and males of the ChlA strain exceeded that in the Lab TY strain specimens by 1.54 (p = 0.08) and 1.83 (p < 0.05) times, respectively, with the same level of CYP6D1 expression. PCR-RFLP analysis revealed a previously undescribed mutation in the promoter region of the CYP6D1 gene in adults of the Lab TY and ChlA strains, and it did not affect the gene expression level. The obtained results show that the development of resistance to chlorfenapyr in M. domestica is accompanied by an increase in P450-monooxygenase activity without changes in CYP6D1 expression. Full article
(This article belongs to the Special Issue How the Detoxification Genes Increase Insect Resistance)
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2 pages, 167 KiB  
Correction
Correction: Szawaryn et al. A New Tribe of the Ladybird Beetle Subfamily Microweiseinae (Coleoptera: Coccinellidae) Discovered on an Island in the North Atlantic Ocean. Insects 2020, 11, 367
by Karol Szawaryn, Jaroslav Větrovec and Wioletta Tomaszewska
Insects 2024, 15(6), 460; https://doi.org/10.3390/insects15060460 - 19 Jun 2024
Viewed by 138
Abstract
The recent paper by Szawaryn et al [...] Full article
11 pages, 8273 KiB  
Article
Utilizing Star Polycation Nanocarrier for the Delivery of miR-184 Agomir and Its Impact on the Life History Traits of the English Grain Aphid, Sitobion avenae
by Cong Zhang, Guohua Wei, Linyuan Wu, Yunhui Zhang, Xun Zhu, Austin Merchant, Xuguo Zhou, Xiangying Liu and Xiangrui Li
Insects 2024, 15(6), 459; https://doi.org/10.3390/insects15060459 - 19 Jun 2024
Viewed by 272
Abstract
The investigation of genetics-based biopesticides has become a central focus in pesticide studies due to their inherent advantages, including species specificity, environmental safety, and a wide range of target genes. In this study, a mixture of miR-184 agomir and nanomaterial star polycation (SPc) [...] Read more.
The investigation of genetics-based biopesticides has become a central focus in pesticide studies due to their inherent advantages, including species specificity, environmental safety, and a wide range of target genes. In this study, a mixture of miR-184 agomir and nanomaterial star polycation (SPc) was used to treat the nymphs of the English grain aphid, Sitobion avenae (F.). The life parameters of the aphids at various developmental stages were analyzed using an age–stage two-sex life table to assess the effect of miR-184 agomir on the experimental population. The results indicated that miR-184 agomir had a significant negative effect on four key life parameters, including the intrinsic rate of increase, the finite rate of increase, the net rate of increase, and the mean generation time. The population prediction revealed a substantial reduction (91.81% and 95.88%) in the population size of S. avenae at 60 d after treatment with miR-184 agomir, compared to the control groups. Our findings suggest that the miR-184 agomir has the potential to reduce the survival rate and mean longevity of S. avenae, highlighting its potential as a promising candidate for the development of an effective genetics-based biopesticide. Full article
(This article belongs to the Special Issue New Advances in Insect Chemical Adaptation)
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13 pages, 1311 KiB  
Article
Pine Response to Sawfly Pheromones: Effects on Sawfly’s Oviposition and Larval Growth
by Asifur Rahman-Soad, Norbert Bittner and Monika Hilker
Insects 2024, 15(6), 458; https://doi.org/10.3390/insects15060458 - 19 Jun 2024
Viewed by 279
Abstract
Insect pheromones have been intensively studied with respect to their role in insect communication. However, scarce knowledge is available on the impact of pheromones on plant responses, and how these in turn affect herbivorous insects. A previous study showed that exposure of pine [...] Read more.
Insect pheromones have been intensively studied with respect to their role in insect communication. However, scarce knowledge is available on the impact of pheromones on plant responses, and how these in turn affect herbivorous insects. A previous study showed that exposure of pine (Pinus sylvestris) to the sex pheromones of the pine sawfly Diprion pini results in enhanced defenses against the eggs of this sawfly; the egg survival rate on pheromone-exposed pine needles was lower than that on unexposed pine. The long-lasting common evolutionary history of D. pini and P. sylvestris suggests that D. pini has developed counter-adaptations to these pine responses. Here, we investigated by behavioral assays how D. pini copes with the defenses of pheromone-exposed pine. The sawfly females did not discriminate between the odor of pheromone-exposed and unexposed pine. However, when they had the chance to contact the trees, more unexposed than pheromone-exposed trees received eggs. The exposure of pine to the pheromones did not affect the performance of larvae and their pupation success. Our findings indicate that the effects that responses of pine to D. pini sex pheromones exert on the sawfly eggs and sawfly oviposition behavior do not extend to effects on the larvae. Full article
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13 pages, 733 KiB  
Article
Variations in Mating and Reproduction in Oriental Fruit Moth Caused by Adult Physiological State in Laboratory Tests
by Weina Kong, Yi Wang, Na Li, Weiye Cao, Xuefeng Hu, Changnian Liu, Guofei Niu, Jie Li and Ruiyan Ma
Insects 2024, 15(6), 457; https://doi.org/10.3390/insects15060457 - 18 Jun 2024
Viewed by 272
Abstract
Grapholita molesta (Busck) is a pest of rosaceous fruit plants worldwide. Due to a combination of monandry and promiscuity in G. molesta, the age and mating history of both sexes significantly affected the mating and reproductive success. In this study, the interactions [...] Read more.
Grapholita molesta (Busck) is a pest of rosaceous fruit plants worldwide. Due to a combination of monandry and promiscuity in G. molesta, the age and mating history of both sexes significantly affected the mating and reproductive success. In this study, the interactions of different ages (3, 5, or 7 days) and mating history (unmated or mated) in each sex on the mating selection, reproductive system, and offspring production were investigated in the laboratory. The results showed that these differences mainly occurred in young females or males, associated with unmated or mated state. Especially, the 3-day-old unmated females were preferred by the 7-day-old males but discriminated against by the 3- or 5-day-old unmated males, whereas the 3-day-old mated males were preferred by the 3-day-old mated or 7-day-old females but discriminated against by the 3- or 5-day-old unmated females. The lengths of the ovarian ducts were affected by age in the unmated females, with the greatest length being found at 7 days old. The size of testes varied with age in the unmated males, being the largest at 3 days old. At 3 days old, the testes size of the unmated males was larger than that of the mated males. The pairing of 5-day-old unmated females × 3-day-old mated males maximized the successful matings. The least productive pairing was 7-day-old unmated females × 5-day-old mated males. The pairing of 5-day-old mated males × 3-day-old mated females had the lowest number of matings and the highest number of offspring. The pairing of 3-day-old mated females × 3-day-old mated males had a high rate of mating success and the most offspring. These results revealed the different roles between females and males because of physiological states in terms of the reproductive biology in G. molesta. Full article
(This article belongs to the Section Insect Physiology, Reproduction and Development)
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15 pages, 4777 KiB  
Article
Impacts of Millipedes on Acari and Collembola Communities—A Microcosm Experiment
by Wenjin Chang, Peng Zhang, Jianwei Li, Nonillon M. Aspe, Jiahua Hao, Siyuan Lu, Zhuoma Wan and Donghui Wu
Insects 2024, 15(6), 456; https://doi.org/10.3390/insects15060456 - 18 Jun 2024
Viewed by 539
Abstract
Ecosystem engineers influence the structure and function of soil food webs through non-trophic interactions. The activity of large soil animals, such as earthworms, has a significant impact on the soil microarthropod community. However, the influence of millipedes on soil microarthropod communities remains largely [...] Read more.
Ecosystem engineers influence the structure and function of soil food webs through non-trophic interactions. The activity of large soil animals, such as earthworms, has a significant impact on the soil microarthropod community. However, the influence of millipedes on soil microarthropod communities remains largely unknown. In this microcosm experiment, we examined the effects of adding, removing, and restricting millipede activity on Acari and Collembola communities in litter and soil by conducting two destructive sampling sessions on days 10 and 30, respectively. At the time of the first sampling event (10 d), Acari and Collembola abundance was shown to increase and the alpha diversity went higher in the treatments with millipedes. At the time of the second sampling event (30 d), millipedes significantly reduced the Collembola abundance and alpha diversity. The results were even more pronounced as the millipedes moved through the soil, which caused the collembolans to be more inclined to inhabit the litter, which in turn resulted in the increase in the abundance and diversity of Acari in the soil. The rapid growth of Collembola in the absence of millipedes significantly inhibited the abundance of Acari. The presence of millipedes altered the community structure of Acari and Collembola, leading to a stronger correlation between the two communities. Changes in these communities were driven by the dominant taxa of Acari and Collembola. These findings suggest that millipedes, as key ecosystem engineers, have varying impacts on different soil microarthropods. This study enhances our understanding of biological interactions and offers a theoretical foundation for soil biodiversity conservation. Full article
(This article belongs to the Special Issue Diversity and Function of Collembola)
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16 pages, 1609 KiB  
Article
Influence of Endogenous Bacteria on Behavioral Responses in Leptocybe invasa: An Analysis of mVOCs
by Leming Zhou, Ping Hu, Jinting Xie, Junjue Li, Chunhui Guo and Zhengde Yang
Insects 2024, 15(6), 455; https://doi.org/10.3390/insects15060455 - 16 Jun 2024
Viewed by 545
Abstract
Microorganisms within insects play a vital role in maintaining the basal physiological functions of the insects, with olfactory signals as critical components of insect survival strategies. Leptocybe invasa (L. invasa), an invasive alien pest inflicting significant damage to eucalyptus trees, harbors [...] Read more.
Microorganisms within insects play a vital role in maintaining the basal physiological functions of the insects, with olfactory signals as critical components of insect survival strategies. Leptocybe invasa (L. invasa), an invasive alien pest inflicting significant damage to eucalyptus trees, harbors a rich and varied bacterial community within its body. However, the impact of its endogenous bacteria and their microbial Volatile Organic Compounds (mVOCs) on the behavioral preferences of L. invasa remains unexplored to date. This study focused on nine cultivable and dominant endogenous bacterial strains within L. invasa. Using a Y-tube olfactometer, we investigated the behavioral responses of female L. invasa to the mVOCs emitted by these bacteria. Concurrently, gas chromatography–mass spectrometry (GC–MS) was employed to quantify the mVOCs produced by these endogenous bacteria. Our findings revealed that Staphylococcus sp. exhibited the highest attractiveness of L. invasa, whereas Microbacterium sp. and E. cloacae exerted the most significant avoidance effects. The analysis of the mVOCs further highlighted the significance of aldehyde compounds, notably 2,3,6-trichlorobenzaldehyde, and alkane compounds, such as eicosane, in mediating the repellency and attraction effects. These results contribute to a deeper understanding of the invasion mechanism of L. invasa and provide a scientific basis for developing novel biopesticides or elicitors. Full article
(This article belongs to the Section Insect Behavior and Pathology)
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20 pages, 1238 KiB  
Article
Identification and Characterization of Hibiscus mutabilis Varieties Resistant to Bemisia tabaci and Their Resistance Mechanisms
by Juan Wei, Xiaoli Liu, Chan Li, Yuanzhao Yang, Cancan Song, Yihao Chen, Qiongda Ciren, Chunxian Jiang and Qing Li
Insects 2024, 15(6), 454; https://doi.org/10.3390/insects15060454 - 14 Jun 2024
Viewed by 199
Abstract
Hibiscus mutabilis, the city flower of Chengdu, is culturally significant and has nutritional and medicinal benefits. However, frequent infestations of Bemisia tabaci have caused economic losses. This study aimed to identify insect−resistant H. mutabilis varieties. Over two years, varieties like Jinqiusong, Zuiyun, [...] Read more.
Hibiscus mutabilis, the city flower of Chengdu, is culturally significant and has nutritional and medicinal benefits. However, frequent infestations of Bemisia tabaci have caused economic losses. This study aimed to identify insect−resistant H. mutabilis varieties. Over two years, varieties like Jinqiusong, Zuiyun, and Zuifurong showed moderate to high resistance based on reproductive indices. Assessments of antixenosis and developmental impacts revealed that adult B. tabaci exhibited low selectivity toward these resistant varieties, indicating a strong repellent effect. Gas chromatography–mass spectrometry analysis identified volatile organic compounds, such as alcohols, alkanes, and terpenes. Notably, 2–ethylhexanol and 6–methylheptanol exhibited repellent properties. Using nontargeted metabolomics, this study compared the metabolite profiles of the insect−resistant variety Jinqiusong (JQS), moderately resistant Bairihuacai (BRHC), and highly susceptible Chongbanbai (CBB) post B. tabaci infestation. Fifteen key metabolites were linked to resistance, emphasizing the phenylpropanoid biosynthesis pathway as crucial in defense. These findings offer a theoretical foundation for breeding insect−resistant H. mutabilis varieties and developing eco−friendly strategies against B. tabaci infestations. Full article
(This article belongs to the Section Insect Pest and Vector Management)
15 pages, 7329 KiB  
Article
Impact of Ae-GRD on Ivermectin Resistance and Its Regulation by miR-71-5p in Aedes aegypti
by Lingling Yu, Yanan Yin, Qiuhui Wang, Peizhen Zhao, Qian Han and Chenghong Liao
Insects 2024, 15(6), 453; https://doi.org/10.3390/insects15060453 - 14 Jun 2024
Viewed by 330
Abstract
iGABAR, a member of the Cys-loop ligand-gated ion channel superfamily, is a significant target of the insecticide ivermectin (IVM). GRD is the potential subunit of the insect iGABAR. However, little information about GRD in Ae. aegypti has been reported. In this study, we [...] Read more.
iGABAR, a member of the Cys-loop ligand-gated ion channel superfamily, is a significant target of the insecticide ivermectin (IVM). GRD is the potential subunit of the insect iGABAR. However, little information about GRD in Ae. aegypti has been reported. In this study, we involved cloning and characterizing the iGABAR subunit GRD of Ae. aegypti (Ae-GRD). Sequence analysis indicated that Ae-GRD, as part of the cysteine-loop ligand-gated ion channel family, is similar to other insect GRD. RNA interference (RNAi) was employed to explore IVM resistance in Ae. aegypti, resulting in a significant reduction in Ae-GRD expression (p < 0.05), and the mortality of Ae. aegypti adults with Ae-GRD knockdown was significantly decreased after exposure to ivermectin. Bioinformatics prediction identified miR-71-5p as a potential regulator of Ae-GRD. In vitro, dual-luciferase reporter assays confirmed that Ae-GRD expression was regulated by miR-71-5p. Microinjection of miR-71-5p mimics upregulated miR-71-5p expression and downregulated Ae-GRD gene expression, reducing mortality by 34.52% following IVM treatment. Conversely, microinjection of a miR-71-5p inhibitor decreased miR-71-5p expression but did not affect the susceptibility to IVM despite increased Ae-GRD expression (p < 0.05). In conclusion, Ae-GRD, as one of the iGABA receptor subunits, is a potential target of ivermectin. It may influence ivermectin resistance by modulating the GABA signaling pathway. The inhibition of Ae-GRD expression by miR-71-5p decreased ivermectin resistance and consequently lowered the mortality rate of Ae. aegypti mosquitoes. This finding provides empirical evidence of the relationship between Ae-GRD and its miRNA in modulating insecticide resistance, offering novel perspectives for mosquito control strategies. Full article
(This article belongs to the Section Medical and Livestock Entomology)
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1 pages, 160 KiB  
Correction
Correction: Pertegal et al. More Than 200 Years Later: Gluvia brunnea sp. nov. (Solifugae, Daesiidae), a Second Species of Camel Spider from the Iberian Peninsula. Insects 2024, 15, 284
by Cristian Pertegal, Pablo Barranco, Eva De Mas and Jordi Moya-Laraño
Insects 2024, 15(6), 452; https://doi.org/10.3390/insects15060452 - 14 Jun 2024
Viewed by 160
Abstract
Text Correction [...] Full article
(This article belongs to the Section Other Arthropods and General Topics)
12 pages, 270 KiB  
Article
Sublethal Effects of Chlorantraniliprole on the Mobility Patterns of Sitophilus spp.: Implications for Pest Management
by Nickolas G. Kavallieratos, Maria C. Boukouvala, Nikoleta Eleftheriadou, Constantin S. Filintas, Demeter Lorentha S. Gidari and Vasiliki Panagiota C. Kyrpislidi
Insects 2024, 15(6), 451; https://doi.org/10.3390/insects15060451 - 13 Jun 2024
Viewed by 311
Abstract
Chlorantraniliprole, an anthranilic diamide insecticide, has emerged as a promising solution for controlling agricultural pests because of its low mammalian toxicity and selectivity towards non-target organisms. This study investigated the sublethal effects of chlorantraniliprole on the mobility behavior of two significant stored-product pests, [...] Read more.
Chlorantraniliprole, an anthranilic diamide insecticide, has emerged as a promising solution for controlling agricultural pests because of its low mammalian toxicity and selectivity towards non-target organisms. This study investigated the sublethal effects of chlorantraniliprole on the mobility behavior of two significant stored-product pests, Sitophilus oryzae (L.) and Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae). Contact toxicity assays revealed varying susceptibility levels between the two species, with S. zeamais showing higher sensitivity. Subsequent analysis of mobility behavior, both in the presence and absence of food, indicated significant differences between chlorantraniliprole-exposed and control groups. While S. oryzae exhibited altered locomotion patterns and a decreased number of food approaches at sublethal concentrations, S. zeamais displayed increased walking time and reduced immobility periods. These findings highlight the importance of considering sublethal effects in understanding the overall impact of chlorantraniliprole on stored-product pests. Further research into the long-term consequences of sublethal exposure is warranted to inform more effective pest management strategies in storage. Full article
(This article belongs to the Section Insect Pest and Vector Management)
15 pages, 1736 KiB  
Article
Lethal and Sublethal Effects of Cyantraniliprole on the Biology and Metabolic Enzyme Activities of Two Lepidopteran Pests, Spodoptera littoralis and Agrotis ipsilon, and A Generalist Predator, Chrysoperla carnea (Neuroptera: Chrysopidae)
by Mona Awad, Ahmed H. El Kenawy, Nawal AbdulAziz Alfuhaid, El-Desoky S. Ibrahim, Júlia Katalin Jósvai, Adrien Fónagy and Moataz A. M. Moustafa
Insects 2024, 15(6), 450; https://doi.org/10.3390/insects15060450 - 13 Jun 2024
Viewed by 459
Abstract
Cyantraniliprole is a novel anthranilic diamide insecticide registered for controlling chewing and sucking insect pests. Here, the lethal and sublethal effects of this insecticide on two destructive lepidopteran pests, Spodoptera littoralis Boisduval and Agrotis ipsilon Hufnagel, were evaluated. Because the effects of novel [...] Read more.
Cyantraniliprole is a novel anthranilic diamide insecticide registered for controlling chewing and sucking insect pests. Here, the lethal and sublethal effects of this insecticide on two destructive lepidopteran pests, Spodoptera littoralis Boisduval and Agrotis ipsilon Hufnagel, were evaluated. Because the effects of novel insecticides on beneficial and non-target arthropods must be considered, the impact of cyantraniliprole on a generalist biological control agent, Chrysoperla carnea [Stephens 1836], were also examined. Overall, our study revealed that cyantraniliprole was more toxic to A. ipsilon than to S. littoralis. Moreover, the LC15 and LC50 of the insecticide significantly prolonged the duration of the larval and pupal stages and induced enzymatic detoxification activity in both species. Treatment of the second-instar larvae of C. carnea with the recommended concentration of cyantraniliprole (0.75 mg/L) doubled the mortality rates and resulted in a slight negative effect on the biology and detoxification enzymes of C. carnea. Our results indicate that both sublethal and lethal concentrations of cyantraniliprole can successfully suppress S. littoralis and A. ipsilon populations. They also suggest that C. carnea, as a generalist predator, is compatible with cyantraniliprole under the modelled realistic field conditions. In future investigations, insights into the effects of cyantraniliprole on S. littoralis, A. ipsilon, and C. carnea under field conditions will be required to appropriately validate our results. Full article
(This article belongs to the Special Issue Sustainable Management of Arthropod Pests in Agroecosystems)
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16 pages, 2703 KiB  
Article
Efficacy of Metarhizium anisopliae, Isolate ICIPE 7, against Anopheles arabiensis, Glossina fuscipes, and Rhipicephalus spp.
by Fedinand Ong’wen, Margaret Mendi Njoroge, Ulrike Fillinger, Heike Lutermann and Tullu Bukhari
Insects 2024, 15(6), 449; https://doi.org/10.3390/insects15060449 - 13 Jun 2024
Viewed by 879
Abstract
Arthropod vectors are responsible for a multitude of human and animal diseases affecting poor communities in sub-Saharan Africa. Their control still relies on chemical agents, despite growing evidence of insecticide resistance and environmental health concerns. Biorational agents, such as the entomopathogenic fungus Metarhizium [...] Read more.
Arthropod vectors are responsible for a multitude of human and animal diseases affecting poor communities in sub-Saharan Africa. Their control still relies on chemical agents, despite growing evidence of insecticide resistance and environmental health concerns. Biorational agents, such as the entomopathogenic fungus Metarhizium anisopliae, might be an alternative for vector control. Recently, the M. anisopliae isolate ICIPE 7 has been developed into a commercial product in Kenya for control of ticks on cattle. We were interested in assessing the potential of controlling not only ticks but also disease-transmitting mosquitoes and tsetse flies using cattle as blood hosts, with the aim of developing a product for integrated vector management. Laboratory bioassays were carried out with M. anisopliae, isolate ICIPE 7 and isolate ICIPE 30, to compare efficacy against laboratory-reared Anopheles arabiensis. ICIPE 7 was further tested against wild Glossina fuscipes and Rhipicephalus spp. Dose–response tests were implemented, period of mosquito exposure was evaluated for effects on time to death, and the number of spores attached to exposed vectors was assessed. Exposure to 109 spores/mL of ICIPE 7 for 10 min resulted in a similar mortality of An. arabiensis as exposure to ICIPE 30, albeit at a slower rate (12 vs. 8 days). The same ICIPE 7 concentration also resulted in mortalities of tsetse flies (LT50: 16 days), tick nymphs (LT50: 11 days), and adult ticks (LT50: 20 days). Mosquito mortality was dose-dependent, with decreasing LT50 of 8 days at a concentration of 106 spores/mL to 6 days at 1010 spores/mL. Exposure period did not modulate the outcome, 1 min of exposure still resulted in mortality, and spore attachment to vectors was dose-dependent. The laboratory bioassays confirmed that ICIPE 7 has the potential to infect and cause mortality to the three exposed arthropods, though at slower rate, thus requiring further validation under field conditions. Full article
(This article belongs to the Special Issue New Formulations of Natural Substances against Insect Pests)
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17 pages, 16012 KiB  
Article
Comparative SEM Study of Sensilla and Tyloid Structures in the Antennae of Vespinae (Hymenoptera: Vespidae)
by Tong Zhou, Xiaojuan Huang, Hasin Ullah, Yan Tang, Danyang Zhu, Hongli Xu, Qian Wen, Xiaoxia Tian and Jiangli Tan
Insects 2024, 15(6), 448; https://doi.org/10.3390/insects15060448 - 13 Jun 2024
Viewed by 304
Abstract
This study investigates the distribution, morphology, and potential functions of antennal sensilla in various wasp species, including Dolichovespula flora, D. intermedia, Vespula structor, Vl. vulgaris, Provespa barthelemyi, Vespa bicolor, V. ducalis, V. mocsaryana, and V. [...] Read more.
This study investigates the distribution, morphology, and potential functions of antennal sensilla in various wasp species, including Dolichovespula flora, D. intermedia, Vespula structor, Vl. vulgaris, Provespa barthelemyi, Vespa bicolor, V. ducalis, V. mocsaryana, and V. velutina var. nigothorax. The study thoroughly analyzes the antennal structure of these species, representing all four genera of the yellow-jacket and hornet subfamily Vespinae. Using scanning electron microscopy (SEM), the study identifies a total of nineteen types of sensilla, including sensilla trichodea (ST-I, ST-II, ST-III), sensilla campaniform (SCF-I, SCF-II, SCF-III), pit organs (SCO-I, SCO-II, and SA), sensilla placodea (SP-I, SP-II), sensilla chaetica (SCH-I, SCH-II), sensilla basiconica (SB-I, SB-II), sensilla agmon (SAG-I, SAG-II), and sensilla coelocapitular (SCA). Additionally, tyloids were observed in the males of seven species, except for Vl. structor and Vl. vulgaris. The study provides insights into these sensilla types’ morphology, abundance, and distribution. It discusses the variations in sensilla morphology among different species and the presence of gender-specific sensilla. This study provides new data about the morphology and distribution patterns of sensilla and tyloid. Full article
(This article belongs to the Collection Hymenoptera: Biology, Taxonomy and Integrated Management)
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14 pages, 2861 KiB  
Article
Spotted Lanternflies Respond to Natural Pheromone Lures for Mate-Finding and Oviposition
by Miriam F. Cooperband and Kelly M. Murman
Insects 2024, 15(6), 447; https://doi.org/10.3390/insects15060447 - 13 Jun 2024
Viewed by 502
Abstract
Using semiochemicals collected from spotted lanternflies Lycorma delicatula (Hemiptera: Fulgoridae) (SLF) and deployed in the field with circle traps, we demonstrated that SLF responded to SLF pheromones: in particular, this was the case for males while seeking mates and for females while ovipositing. [...] Read more.
Using semiochemicals collected from spotted lanternflies Lycorma delicatula (Hemiptera: Fulgoridae) (SLF) and deployed in the field with circle traps, we demonstrated that SLF responded to SLF pheromones: in particular, this was the case for males while seeking mates and for females while ovipositing. The attractants consisted of SLF body extract emitted from diffuser lures and SLF honeydew on burlap ribbons, collected from heavily infested locations. Traps with attractants were deployed in field sites with very light SLF infestations to avoid competing signals of pre-existing aggregations. The number of SLF equivalents emitted by each diffuser per trapping period was used in a dose–response analysis. Three trees per block received either (1) a control hexane lure and a clean ribbon, (2) a lure containing SLF extract and a clean ribbon, or (3) a lure containing SLF extract and a honeydew-laden ribbon. Ten blocks were sampled three times per week for twelve weeks. We found a significant positive dose–response by males to SLF body extract only in the presence of SLF honeydew, indicating a synergistic effect between honeydew volatiles and body volatiles. This dose–response occurred for five weeks after mating started, after which males no longer responded. Subsequently, females had a significant positive dose–response to SLF extract only in the presence of honeydew when oviposition was their primary activity, continuing for two weeks, suggesting that females may use pheromones to aggregate for oviposition. The extract in the absence of honeydew did not result in a positive dose–response, nor did the hexane control. These findings suggest that SLF respond synergistically to the combination of pheromones present in both SLF honeydew and SLF bodies. Thus, combining key components from both sources may aid the development of semiochemical lures for SLF. Full article
(This article belongs to the Collection Insect Signals)
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13 pages, 1563 KiB  
Article
Drosophila melanogaster Limostatin and Its Human Ortholog Promote West Nile Virus Infection
by Ezra B. Mead, Miyoung Lee, Chasity E. Trammell and Alan G. Goodman
Insects 2024, 15(6), 446; https://doi.org/10.3390/insects15060446 - 12 Jun 2024
Viewed by 504
Abstract
The arbovirus West Nile virus (WNV) is a danger to global health. Spread primarily by mosquitoes, WNV causes about 2000 cases per year in the United States. The natural mosquito immune response controls viral replication so that the host survives but can still [...] Read more.
The arbovirus West Nile virus (WNV) is a danger to global health. Spread primarily by mosquitoes, WNV causes about 2000 cases per year in the United States. The natural mosquito immune response controls viral replication so that the host survives but can still transmit the virus. Using the genetically malleable Drosophila melanogaster model, we previously dissected innate immune pathways used to control WNV infection. Specifically, we showed that insulin/IGF-1 signaling (IIS) activates a JAK/STAT-mediated immune response that reduces WNV. However, how factors that regulate IIS in insects control infection has not been identified. D. melanogaster Limostatin (Lst) encodes a peptide hormone that suppresses insulin secretion. Its mammalian ortholog, Neuromedin U (NMU), is a peptide that regulates the production and secretion of insulin from pancreatic beta cells. In this study, we used D. melanogaster and human cell culture models to investigate the roles of these insulin regulators in immune signaling. We found that D. melanogaster Lst mutants, which have elevated insulin-like peptide expression, are less susceptible to WNV infection. Increased levels of insulin-like peptides in these flies result in upregulated JAK/STAT activity, leading to protection from infection. Treatment of human cells with the insulin regulator NMU results in increased WNV replication. Further investigation of methods to target Lst in mosquitoes or NMU in mammals can improve vector control methods and may lead to improved therapeutics for human and animal infection. Full article
(This article belongs to the Collection Insect Immunity: Evolution, Genomics and Physiology)
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10 pages, 633 KiB  
Article
Pheromone-Based Mating Disruption of Conogethes punctiferalis (Lepidoptera: Crambidae) in Chestnut Orchards
by Junheon Kim, Seongchae Jung and Young Un Kim
Insects 2024, 15(6), 445; https://doi.org/10.3390/insects15060445 - 12 Jun 2024
Viewed by 506
Abstract
Chestnuts (Castanea crenata Siebold and Zucc.) are one of the major agroforestry products in Korea, and Conogethes punctiferalis is a major pest of the chestnut fruit. Pheromone-based mating disruption (MD) has emerged as a promising eco-friendly approach to reduce population levels and [...] Read more.
Chestnuts (Castanea crenata Siebold and Zucc.) are one of the major agroforestry products in Korea, and Conogethes punctiferalis is a major pest of the chestnut fruit. Pheromone-based mating disruption (MD) has emerged as a promising eco-friendly approach to reduce population levels and ultimately mitigate fruit damage. Field trials were conducted over two years (2022–2023) in two commercial chestnut orchards in Central Korea that were infested with C. punctiferalis. Compared with the control treatment, the MD treatment effectively reduced the number of male C. punctiferalis captured in the MD treatment plots. Male catch inhibition (MCI) rates ranged from 70.5% to 82.7% in 2022 and from 87.8% to 95.1% in 2023. The MD efficacy (%) was calculated based on the total number of chestnut fruits collected and the number of fruits damaged by C. punctiferalis. In 2022, the MD efficacy of the single-dosage treatment (TS, 50 g/ha) was 63.9% in Orchard A and 73.6% in Orchard B. In 2023, the MD efficacies of the double-dosage treatment (TD, 100 g/ha) and the two-application treatment (TT, 50 g/ha in June and August) were 60.2% and 77.9% in Orchard A and 50.9% and 64.8% in Orchard B, respectively. This study confirms the efficacy of pheromone-based MD in reducing the C. punctiferalis numbers in chestnut orchards and damage to chestnut fruits. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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12 pages, 1193 KiB  
Article
Implications of Temperature and Prey Density on Predatory Mite Amblyseius swirskii (Acari: Phytoseiidae) Functional Responses
by Mohammed M. E. Elmoghazy, Dalia Mahmoud Abdelmonem Elsherbini, Abadi M. Mashlawi, Ateya Megahed Ibrahim, Ahmed A. El-Mansi and Mohamed El-Sherbiny
Insects 2024, 15(6), 444; https://doi.org/10.3390/insects15060444 - 12 Jun 2024
Viewed by 510
Abstract
Amblyseius swirskii are predaceous mites that feed on phytophagous mites, pollens, and plant exudates and are known as one of the most potent biological pest management agents. Tetranychus urticae is a global mite that is difficult to manage because of its high population [...] Read more.
Amblyseius swirskii are predaceous mites that feed on phytophagous mites, pollens, and plant exudates and are known as one of the most potent biological pest management agents. Tetranychus urticae is a global mite that is difficult to manage because of its high population growth rates, necessitating alternative management measures like biological control. Regarding the functional response, the effects of temperature and prey density are some of the essential behaviors of natural enemies. This study investigates the effect of varying temperatures and prey densities on A. swirskii, a biological control agent for T. urticae. The present results demonstrated the change in the functional response estimates when A. swirskii was reared at various temperatures and different prey densities. The results of the estimates regarding the searching efficiency (a′) showed the highest value (a′ = 0.919) at 26 °C and the lowest value (a′ = 0.751) at 14 °C. The handling time per prey item (Th) for the predatory mites changed with the temperature and prey density, showing the shortest handling time at 26 °C (Th = 0.005) and the highest value at 14 °C (Th = 0.015). The functional response curves matched the type II functional response model, demonstrating the inverse dependence of temperatures and prey density with a positive quadratic coefficient. The predation curves for A. swirskii showed a significant difference between the mean numbers of T. urticae consumed at various prey densities and temperatures, illustrating a relationship between A. swirskii and T. urticae. Therefore, the results of this research may be utilized to forecast the behavior of A. swirskii and its usefulness in controlling T. urticae populations. Full article
(This article belongs to the Collection Plant Responses to Insect Herbivores)
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15 pages, 3817 KiB  
Article
Population Density-Dependent Developmental Regulation in Migratory Locust
by Sifan Shen, Long Zhang and Liwei Zhang
Insects 2024, 15(6), 443; https://doi.org/10.3390/insects15060443 - 11 Jun 2024
Viewed by 363
Abstract
Insect development is intricately governed by hormonal signaling pathways, yet the pivotal upstream regulator that potentiates hormone activation remains largely elusive. The migratory locust, Locusta migratoria, exhibits population density-dependent phenotypic plasticity, encompassing traits such as flight capability, body coloration, and behavior. In [...] Read more.
Insect development is intricately governed by hormonal signaling pathways, yet the pivotal upstream regulator that potentiates hormone activation remains largely elusive. The migratory locust, Locusta migratoria, exhibits population density-dependent phenotypic plasticity, encompassing traits such as flight capability, body coloration, and behavior. In this study, we elucidated a negative correlation between population density and ontogenetic development during the nymphal stage of locusts. We found that the level of density influences the developmental trajectory by modulating transcript abundance within the ecdysone signaling pathway, with knockdown of the prothoracicotropic hormone (PTTH) resulting in developmental delay. Transcriptomic analysis of locust brains across solitary and gregarious phases revealed significant differential expression of genes involved in various pathways, including protein synthesis, energy metabolism, hormonal regulation, and immunity. Notably, knockdown experiments targeting two energy regulators, adipokinetic hormone (AKH) and insulin-like polypeptide 1 (ilp1), failed to elicit changes in the developmental process in solitary locusts. However, knockdown of immunoglobulin (IG) significantly shortened the developmental time in higher-density populations. Collectively, our findings underscore the regulatory role of population density in determining developmental duration and suggest that an immune-related gene contributes to the observed differences in developmental patterns. Full article
(This article belongs to the Section Insect Physiology, Reproduction and Development)
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18 pages, 9143 KiB  
Article
New Genera and Species of Trigonidiidae (Orthoptera: Grylloidea) from the Mid-Cretaceous of Myanmar with a Redescription of Birmaninemobius hirsutus
by Jun-Jie Gu, Yi Zhou and Wei Yuan
Insects 2024, 15(6), 442; https://doi.org/10.3390/insects15060442 - 11 Jun 2024
Viewed by 379
Abstract
The abundance of insects in Burmese amber illustrates a highly diverse insect community from the mid-Cretaceous period; yet, records of crickets (Grylloidea) are notably scarce. In this study, we describe two new genera with three new species, Palaeotrigonidium concavoculus gen. et sp. nov., [...] Read more.
The abundance of insects in Burmese amber illustrates a highly diverse insect community from the mid-Cretaceous period; yet, records of crickets (Grylloidea) are notably scarce. In this study, we describe two new genera with three new species, Palaeotrigonidium concavoculus gen. et sp. nov., Palaeotrigonidium defectivus sp. nov., and Tricalcaratus longilineus gen. et sp. nov., based on three specimens collected in north Myanmar. These new species can be placed within the Trigonidiidae (Orthoptera: Grylloidea) by their triangular head, compound eyes that protrude in dorsal view, and a body entirely covered with robust setae, particularly noticeable in the head and pronotum; however, subfamily assignments are not possible. Another known species, Birmaninemobius hirsutus, Xu et al., 2020, from Myanmar amber is redescribed based on a new specimen and a recheck of the holotype. Full article
(This article belongs to the Section Insect Systematics, Phylogeny and Evolution)
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15 pages, 2182 KiB  
Article
The Innate Rates of Increase in Two Common Stored Grain Insects under Different Grain Storage Conditions and Times
by Fuji Jian
Insects 2024, 15(6), 441; https://doi.org/10.3390/insects15060441 - 11 Jun 2024
Viewed by 329
Abstract
The determination of innate rate of increase (r) values under different grain storage conditions is critical for insect population predictions. The r values for Cryptolestes ferrugineus (Stephens) and Tribolium castaneum (Herbst) were calculated by using a new suggested method (continuous time [...] Read more.
The determination of innate rate of increase (r) values under different grain storage conditions is critical for insect population predictions. The r values for Cryptolestes ferrugineus (Stephens) and Tribolium castaneum (Herbst) were calculated by using a new suggested method (continuous time analysis) and data from the literature, and these calculated r values were compared to identify the r values and carrying capacities under real grain storage conditions and times. The insects were reared in small glass vials (0.3 kg wheat), small PVC columns (2 kg wheat), large PVC columns (14 kg wheat), and shallow containers (14 kg wheat or wheat + cracked wheat). The wheat or cracked wheat had 13.8 to 14.5% moisture contents at different constant temperatures (17.5 to 42.5 °C) and fluctuating temperatures. The r values at the beginning of the population were the highest. Before r became negative, it gradually decreased with increasing time. After the r value became negative, it sometimes increased to positive; however, the rebounded r was much less than the initial r and gradually tended to stabilize within an up-and-down range. This up-and-down r was related to the carrying capacity. The larger the grain bulk, the higher the innate rate was for both species. The r values associated with 14 kg of wheat could be used to predict the insect population dynamics in stored grain bins. Full article
(This article belongs to the Section Insect Ecology, Diversity and Conservation)
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12 pages, 1632 KiB  
Article
Lethal, Sublethal, and Offspring Effects of Fluralaner and Dinotefuran on Three Species of Bactrocera Fruit Flies
by Doudou Li, Xinyan Cai, Yixiang Qi, Yongyue Lu and Xinlian Li
Insects 2024, 15(6), 440; https://doi.org/10.3390/insects15060440 - 11 Jun 2024
Viewed by 447
Abstract
Fruit flies cause substantial economic damage, and their management relies primarily on chemical insecticides. However, pesticide resistance has been reported in several fruit fly species, the mitigation of which is crucial to enhancing fruit fly control. Here, we assess the toxicity of a [...] Read more.
Fruit flies cause substantial economic damage, and their management relies primarily on chemical insecticides. However, pesticide resistance has been reported in several fruit fly species, the mitigation of which is crucial to enhancing fruit fly control. Here, we assess the toxicity of a novel insecticide (fluralaner) and a common insecticide (dinotefuran) against three fruit fly species, Bactrocera dorsalis (Hendel), Bactrocera cucurbitae (Coquillett), and Bactrocera tau (Walker). Both pesticides exhibit robust lethal and sublethal effects against all three fruit fly species, with fluralaner being more potent. Fluralaner and dinotefuran suppress the reproductive capacities and survival rates of fruit flies. However, at the 50% lethal concentration, fluralaner stimulates the reproductive capacity of B. dorsalis and the survival rate of B. tau. Fluralaner also causes significant transgenerational effects, impacting the offspring hatching rate of B. cucurbitae and B. tau and reducing the proportion of female offspring. Thus, both pesticides exhibit high potential for controlling fruit flies. However, their application should be tailored according to species variations and the diverse effects they may induce. Collectively, the findings of this study outline the sublethal effects of two insecticides against fruit flies, helping to optimize their application to ensure the effective management of insecticide resistance. Full article
(This article belongs to the Special Issue Monitoring and Management of Invasive Insect Pests)
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13 pages, 11368 KiB  
Article
Two New Species of Pentacarinus from the Acrotiarini Tribe in Burmese Amber (Hemiptera, Fulgoromorpha, Cixiidae)
by Keyi Deng, Feiyang Liang, Thierry Bourgoin and Menglin Wang
Insects 2024, 15(6), 439; https://doi.org/10.3390/insects15060439 - 11 Jun 2024
Viewed by 357
Abstract
Two new species, Pentacarinus maculosus sp. nov. and Pentacarinus tenebrosus sp. nov., from Burmese amber are described. Alongside the type species P. kachinensis already described, they are easily distinguishable by the tegmina patterns. The diagnosis of the genus Pentacarinus is amended, notably with [...] Read more.
Two new species, Pentacarinus maculosus sp. nov. and Pentacarinus tenebrosus sp. nov., from Burmese amber are described. Alongside the type species P. kachinensis already described, they are easily distinguishable by the tegmina patterns. The diagnosis of the genus Pentacarinus is amended, notably with fusion of Pcu + A1 distad of forking CuA, the fork ScP + R approximately close to basal 1/5 of tegmen, basad of forking CuA, and only one transverse veinlet ir between RP and RA on forewings. Additionally, a key to these three species of Pentacarinus is provided. Full article
(This article belongs to the Section Insect Systematics, Phylogeny and Evolution)
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17 pages, 540 KiB  
Article
Evaluation of Biopesticides for Management of Bemisia tabaci Middle East-Asia Minor 1 (Hemiptera: Aleyrodidae) in Florida
by Marcelo Dimase, Sriyanka Lahiri, Julien Beuzelin, Sam Hutton and Hugh Adam Smith
Insects 2024, 15(6), 438; https://doi.org/10.3390/insects15060438 - 10 Jun 2024
Viewed by 321
Abstract
The sweetpotato whitefly, Bemisia tabaci MEAM1, is a pest known to significantly impact tomato development and yields through direct damage and virus transmission. To manage this pest, the current study compared the effectiveness of various insecticide rotations. Field trials included rotations involving synthetic [...] Read more.
The sweetpotato whitefly, Bemisia tabaci MEAM1, is a pest known to significantly impact tomato development and yields through direct damage and virus transmission. To manage this pest, the current study compared the effectiveness of various insecticide rotations. Field trials included rotations involving synthetic insecticides, biochemicals, and microbial agents, applied according to their highest labeled concentrations. The results indicated that while standard synthetic insecticides consistently reduced whitefly egg and nymph counts significantly, microbial biopesticide rotations also achieved reductions, although less consistently. This study demonstrated that while traditional chemical treatments remain highly effective, microbial biopesticides containing Beauveria bassiana and Cordyceps javanica present a viable alternative to manage MEAM1 in tomato fields. The data generated in this study provided baseline information for further investigations to determine the potential for optimizing integrated pest management (IPM) and insecticide resistance management (IRM) strategies by incorporating microbial biopesticides in rotations with a variety of modes of action to sustainably manage B. tabaci MEAM1 populations in agricultural settings. Full article
(This article belongs to the Section Insect Pest and Vector Management)
14 pages, 6229 KiB  
Article
Predicting the Impact of Climate Change on the Future Distribution of Paederus fuscipes Curtis, 1826, in China Based on the MaxEnt Model
by Hui Gao, Xinju Wei, Yaqin Peng and Zhihang Zhuo
Insects 2024, 15(6), 437; https://doi.org/10.3390/insects15060437 - 9 Jun 2024
Viewed by 414
Abstract
Paederus fuscipes Curtis, 1826, belongs to the Coleoptera order, Staphylinidae family, and Paederus genus (Fabricius, 1775). It has a wide distribution and strong invasive and environmental adaptation capabilities. As a predatory natural enemy of agricultural and forestry pests, understanding its suitable habitat is [...] Read more.
Paederus fuscipes Curtis, 1826, belongs to the Coleoptera order, Staphylinidae family, and Paederus genus (Fabricius, 1775). It has a wide distribution and strong invasive and environmental adaptation capabilities. As a predatory natural enemy of agricultural and forestry pests, understanding its suitable habitat is crucial for the control of other pests. This study, for the first time, uses the MaxEnt model and ArcGIS software, combining known distribution information of P. fuscipes and climate environmental factors to predict the current and future suitable habitat distribution of this insect. The key environmental variables affecting the distribution of P. fuscipes have been identified as mean diurnal range (mean of monthly (max temp-min temp)) (bio2), isothermality (Bio2/Bio7) (*100) (bio3), minimum temperature of the coldest month (bio6), temperature annual range (bio5-bio6) (bio7), mean temperature of the driest quarter (bio9), mean temperature of the coldest quarter (bio11), precipitation of the wettest month (bio13), precipitation of the driest month (bio14), and precipitation seasonality (coefficient of variation) (bio15). The highly suitable areas for P. fuscipes in China are mainly distributed in the hilly regions of Shandong, the North China Plain, and the middle and lower reaches of the Yangtze River Plain, with a total suitable area of 118.96 × 104 km2, accounting for 12.35% of China’s total area. According to future climate change scenarios, it is predicted that the area of highly and lowly suitable regions will significantly decrease, while moderately suitable regions will increase (except for the 2090s, SSP2-4.5 scenario). These research findings provide important theoretical support for pest control and ecological conservation applications. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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11 pages, 2522 KiB  
Article
Molecular Mechanism Underlying ROS-Mediated AKH Resistance to Imidacloprid in Whitefly
by Jingjing Li, Chaoqiang Zhu, Yunhao Xu, Haifang He, Chenchen Zhao and Fengming Yan
Insects 2024, 15(6), 436; https://doi.org/10.3390/insects15060436 - 8 Jun 2024
Viewed by 552
Abstract
Synthetic insecticides used to control Bemisia tabaci include organophosphorus, pyrethroids, insect growth regulators, nicotinoids, and neonicotinoids. Among these, neonicotinoids have been used continuously, which has led to the emergence of high-level resistance to this class of chemical insecticides in the whitefly, making whitefly [...] Read more.
Synthetic insecticides used to control Bemisia tabaci include organophosphorus, pyrethroids, insect growth regulators, nicotinoids, and neonicotinoids. Among these, neonicotinoids have been used continuously, which has led to the emergence of high-level resistance to this class of chemical insecticides in the whitefly, making whitefly management difficult. The adipokinetic hormone gene (AKH) and reactive oxygen species (ROS) play roles in the development of insect resistance. Therefore, the roles of AKH and ROS in imidacloprid resistance in Bemisia tabaci Mediterranean (MED; formerly biotype Q) were evaluated in this study. The expression level of AKH in resistant B. tabaci MED was significantly lower than that in sensitive B. tabaci (MED) (p < 0.05). AKH expression showed a decreasing trend. After AKH silencing by RNAi, we found that ROS levels as well as the expression levels of the resistance gene CYP6CM1 and its upstream regulatory factors CREB, ERK, and P38 increased significantly (p < 0.05); additionally, whitefly resistance to imidacloprid increased and mortality decreased (p < 0.001). These results suggest that AKH regulates the expression of resistance genes via ROS in Bemisia tabaci. Full article
(This article belongs to the Special Issue Monitoring and Management of Invasive Insect Pests)
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16 pages, 3044 KiB  
Article
Newly Woody Artificial Diet Reveals Antibacterial Activity of Hemolymph in Larvae of Zophobas atratus (Fabricius, 1775) (Coleoptera: Tenebrionidae)
by Alexander Kuprin, Vladislava Baklanova, Maria Khandy, Andrei Grinchenko and Vadim Kumeiko
Insects 2024, 15(6), 435; https://doi.org/10.3390/insects15060435 - 8 Jun 2024
Viewed by 608
Abstract
The rearing of saproxylic insects in laboratory conditions is an important task for studying the biology of insects. Through understanding nutritional needs, it is possible to optimize beetle rearing in laboratory conditions. In this study, an artificial fungi-based diet (FD) was developed for [...] Read more.
The rearing of saproxylic insects in laboratory conditions is an important task for studying the biology of insects. Through understanding nutritional needs, it is possible to optimize beetle rearing in laboratory conditions. In this study, an artificial fungi-based diet (FD) was developed for the cultivation of the darkling beetle Zophobas atratus (Fabricius, 1775) (Coleoptera: Tenebrionidae) in laboratory conditions as a model object for studying the biology of saproxylophagous beetles. To assess the influence of the diet, a number of physiological parameters were measured, including development time, body size, and weight of all stages of the beetle’s life cycle, as well as its immune status. The immune status of Z. atratus was assessed on the basis of larval hemolymph antibacterial activity against six different bacterial strains assessed using disk-diffusion and photometric tests. Our findings show that the FD reduces development time and boosts the immune status as compared to beetles reared on a standard diet (SD). Samples from FD-reared larvae had pronounced antibacterial activity as compared to samples from SD-reared larvae. This work is of fundamental importance for understanding the correlations between nutrition and development of saproxylic Coleoptera and is the first report on immune status regulation in this group of insects. Full article
(This article belongs to the Special Issue Insect Rearing: Reserve Forces with Commercial and Ecological Values)
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49 pages, 6695 KiB  
Article
A Taxonomic Revision of the Genus Cleopus Dejean, 1821 (Coleoptera, Curculionidae), with Descriptions of 13 New Species
by Michael Košťál and Roberto Caldara
Insects 2024, 15(6), 434; https://doi.org/10.3390/insects15060434 - 7 Jun 2024
Viewed by 362
Abstract
The genus Cleopus Dejean, 1821 is herein revised for the first time. Based on adult morphological characteristics, 18 species are recognized as valid. Thirteen species, all distributed in the Eastern Palaearctis or Oriental region, are described as new: C. aduncirostris sp. n.; C. [...] Read more.
The genus Cleopus Dejean, 1821 is herein revised for the first time. Based on adult morphological characteristics, 18 species are recognized as valid. Thirteen species, all distributed in the Eastern Palaearctis or Oriental region, are described as new: C. aduncirostris sp. n.; C. cognatus sp. n.; C. confusus sp. n.; C. dohertyi sp. n.; C. hajeki sp. n.; C. lirenae sp. n.; C. longitarsis sp. n.; C. minutus sp. n.; C. pallidisquamosus sp. n.; C. parvidentatus sp. n.; C. philippinensis sp. n.; C. simillimus sp. n.; and C. subaequalis sp. n. Lectotypes of following two valid species and three synonyms were designated: Curculio solani Fabricius, 1792; Curculio pulchellus Herbst, 1795; Cionus setiger Germar, 1821; Curculio immunis Marsham, 1802; and Cleopus pulchellus rigidus Stephens, 1831. Neotypes of Curculio perpensus Rossi, 1792 and Cleopus pulchellus flavus Stephens, 1832 were designated. The following new synonyms of Cleopus pulchellus (Herbst, 1795) were established: Cleopus pulchellus var. flavus Stephens, 1831 syn. n. and C. pulchellus var. rigidus Stephens, 1831 syn. n. Full article
(This article belongs to the Section Insect Systematics, Phylogeny and Evolution)
10 pages, 509 KiB  
Article
Phototactic Changes in Phthorimaea absoluta Long-Wavelength Opsin Gene Mutants (LW2−/−) and Short-Wavelength Opsin Gene Mutant (BL−/−) Strains
by Yanhong Tang, Xiaodi Wang, Jianyang Guo, Nianwan Yang, Dongfang Ma, Fanghao Wan, Chi Zhang, Zhichuang Lü, Jianying Guo and Wanxue Liu
Insects 2024, 15(6), 433; https://doi.org/10.3390/insects15060433 - 7 Jun 2024
Viewed by 311
Abstract
Phthorimaea absoluta (Meyrick) is an invasive pest that has caused damage to tomatoes and other crops in China since 2017. Pest control is mainly based on chemical methods that pose significant threats to food safety and environmental and ecological security. Light-induced control, a [...] Read more.
Phthorimaea absoluta (Meyrick) is an invasive pest that has caused damage to tomatoes and other crops in China since 2017. Pest control is mainly based on chemical methods that pose significant threats to food safety and environmental and ecological security. Light-induced control, a green prevention and control technology, has gained attention recently. However, current light-trapping technology is non-specific, attracting targeted pests alongside natural enemies and non-target organisms. In this study, we characterized the phototactic behavior of tomato leaf miners for the development a specific light-trapping technology for pest control. In situ hybridization revealed opsin expression throughout the body. Furthermore, we investigated the tropism of pests (wild T. absoluta, Toxoptera graminum, and Bemisia tabaci) and natural enemies (Nesidiocoris tenuis and Trichogramma pintoi) using a wavelength-lamp tropism experiment. We found that 365 ± 5 nm light could accurately trap wild P. absoluta without trapping natural enemies and other insects. Finally, we analyzed the phototactic behavior of the mutant strains LW2(−/−) and BL(−/−). LW2 and BL mutants showed significant differences in phototactic behavior. The LW2(−/−) strain was attracted to light at 390 ± 5 nm and the BL(−/−) strain was unresponsive to any light. Our findings will help to develop specific light-trapping technology for controlling tomato leaf miners, providing a basis for understanding pest population dynamics and protecting crops against natural enemies. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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