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1.
J Insect Sci ; 21(1)2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33560361

RESUMO

Pest management of emerging pests can be challenging because very little fundamental knowledge is available to inform management strategies. One such pest, the red-headed flea beetle Systena frontalis (Fabricius) (Coleoptera: Chrysomelidae), is increasingly being identified as a pest of concern in cranberries Vaccinium macrocarpon Aiton (Ericales: Ericaceae). To improve our understanding of this pest and to develop more targeted management programs, we conducted field and laboratory studies to characterize the development, seasonal emergence patterns, and density-dependent plant injury. We found that significantly more flea beetle eggs hatched when exposed to sustained cold treatment between 0 and 5°C for 15 wk than at warmer temperatures, and for shorter and longer cold-period durations. The adults emerged sporadically over the summer, were patchily distributed, fed on both fruit and foliage, and preferentially fed on new plant growth. Using soil cores, we found eggs and larvae located relatively deep (>30 cm) in the soil. These patterns indicate that S. frontalis likely overwinters as eggs, and that targeting the larval stage may be the most effective management approach. Despite the cryptic nature of the larvae, continuing to improve our understanding of this life stage will be critical to optimizing control strategies.


Assuntos
Besouros/fisiologia , Herbivoria , Controle de Insetos , Traços de História de Vida , Vaccinium macrocarpon , Animais , Besouros/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Óvulo/crescimento & desenvolvimento , Densidade Demográfica , Vaccinium macrocarpon/crescimento & desenvolvimento , Wisconsin
2.
J Insect Sci ; 21(1)2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33560362

RESUMO

Laricobius nigrinus (Coleoptera: Derodontidae) Fender and Laricobius osakensis (Coleoptera: Derodontidae) Montgomery and Shiyake have been mass produced by Virginia Tech as biological control agents for the hemlock woolly adelgid (HWA), Adelges tsugae (Hemiptera: Adelgidae) Annand, for the past 15 and 9 yr, respectively. Herein, we describe modifications of our rearing procedures, trends and analyses in the overall production of these agents, and the redistribution of these agents for release to local and federal land managers. Based on these data, we have highlighted three major challenges to the rearing program: 1) high mortality during the subterranean portion of its life cycle (averaging 37% annually) reducing beetle production, 2) asynchrony in estivation emergence relative to the availability of their host HWA minimizing food availability, and 3) unintended field collections of Laricobius spp. larvae on HWA provided to lab-reared larvae complicating rearing procedures. We further highlight corresponding avenues of research aimed at addressing each of these challenges to further improve Laricobius spp. production.


Assuntos
Besouros/fisiologia , Hemípteros/fisiologia , Controle Biológico de Vetores/métodos , Animais , Agentes de Controle Biológico , Besouros/crescimento & desenvolvimento , Hemípteros/crescimento & desenvolvimento , Cicutas (Apiáceas)/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Larva/fisiologia , Ninfa/crescimento & desenvolvimento , Ninfa/fisiologia , Virginia
3.
Food Chem ; 338: 128073, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32950872

RESUMO

Protein digestibility of Protaetia brevitarsis larvae before and after defatting by hexane was compared with that of beef loin in an in vitro digestion model. Larvae had higher crude protein content and 10% trichloroacetic acid (10% TCA)-soluble α-amino groups than beef. Decreases in the levels of total free sulfhydryl groups and 10% TCA-soluble α-amino groups were detected in larvae and beef after defatting (P < 0.05). Surface hydrophobicity increased after defatting in both larvae and beef, (P < 0.05) and tryptophan fluorescence intensity decreased in defatted larvae but increased in defatted beef. Levels of proteins digested into sizes under 3 and 10 kDa in larvae were higher than those in beef (P < 0.05), and defatting did not induce an effect in larvae. Therefore, in the aspect of high protein content and digestibility, larvae of P. brevitarsis can be a potential substitute of animal proteins.


Assuntos
Besouros/metabolismo , Proteínas de Insetos/metabolismo , Carne/análise , Proteínas/metabolismo , Animais , Bovinos , Besouros/crescimento & desenvolvimento , Digestão , Hexanos/química , Larva/metabolismo , Compostos de Sulfidrila/análise
4.
PLoS One ; 15(9): e0236653, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32956411

RESUMO

Symbiosis can facilitate the development of specialized organs in the host body to maintain relationships with beneficial microorganisms. To understand the developmental and genetic mechanisms by which such organs develop, it is critical to first investigate the morphology and developmental timing of these structures during the onset of host development. We utilized micro-computed tomography (µCT) to describe the morphology and development of mycangia, a specialized organ, in the Asian ambrosia beetle species Euwallacea validus which maintains a mutualistic relationship with the Ascomycete fungus, Fusarium oligoseptatum. We scanned animals in larval, pupal and adult life stages and identified that mycangia develop during the late pupal stage. Here we reconcile preliminary evidence and provide additional morphological data for a second paired set of structures, including the superior, medial mycangia and an inferior, lateral pair of pouch-like structures, in both late-stage pupae and adult female beetles. Furthermore, we report the possible development of rudimentary, or partially developed pairs of medial mycangia in adult male beetles which has never been reported for any male Xyleborini. Our results illustrate the validity of µCT in observing soft tissues and the complex nature of mycangia morphology and development.


Assuntos
Besouros/crescimento & desenvolvimento , Besouros/ultraestrutura , Animais , Besouros/anatomia & histologia , Feminino , Larva/anatomia & histologia , Larva/crescimento & desenvolvimento , Larva/ultraestrutura , Masculino , Pupa/anatomia & histologia , Pupa/crescimento & desenvolvimento , Pupa/ultraestrutura , Caracteres Sexuais , Microtomografia por Raio-X
5.
Bull Entomol Res ; 110(6): 694-699, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32912368

RESUMO

Body size is a trait with many potential impacts on fitness. Adult body size can affect the strength of condition-dependent parental effects that determine offspring phenotypes, with potentially important transgenerational consequences. In a preliminary experiment, larval food deprivation (30 min daily access) created Harmonia axyridis Pallas (Coleoptera: Coccinellidae) females that weighed <50% of controls reared on ad libitum food (eggs of Ephestia kuehniella Zeller). Although only 1/3 of larvae survived to adulthood in the 30 min treatment, adult pairs produced eggs that were not significantly different in size from those of pairs fed ad libitum as larvae. Less extreme larval food deprivation (4 h daily access) was used to create a cohort of H. axyridis that weighed <60% of controls reared on ad libitum food. Small couples had lower 20-day fecundities and reduced egg fertility relative to large couples. Both egg and pupal periods were shortest when both parents were small, and longest when both parents were large, with reciprocal crosses intermediate. There were no consistent effects of parental body size on larval development time, but the progeny of small females mated to large males pupated later than other treatments. Progeny of large pairs had the heaviest adult weights at emergence, and progeny of small pairs, the lightest, with the progeny of reciprocal crosses intermediate. Small females produced the lightest female offspring, whereas small males sired the lightest male offspring, suggesting stronger responses to epigenetic signals from parents of the same sex. These results indicate that H. axyridis cohorts maturing with abundant food will produce progeny with larger potential body size and fitness, whereas those experiencing food limitation will confer size and fitness limitations to the subsequent generation, with potentially important implications for short-term population dynamics.


Assuntos
Tamanho Corporal , Besouros/crescimento & desenvolvimento , Besouros/fisiologia , Privação de Alimentos , Animais , Feminino , Fertilidade , Larva/crescimento & desenvolvimento , Larva/fisiologia , Masculino , Herança Materna , Mariposas , Óvulo , Herança Paterna , Fenótipo , Reprodução/fisiologia
6.
PLoS One ; 15(7): e0237094, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32735582

RESUMO

Western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is a major pest of corn in the United States. Transgenic corn expressing insecticidal proteins derived from the bacterium Bacillus thuringiensis (Bt) is an important tool used to manage rootworm populations. However, field-evolved resistance to Bt threatens this technology. In areas where resistance is present, resistant individuals may travel from one field to a neighboring field, spreading resistance alleles. An important question that remains to be answered is the extent to which greater-than-expected root injury (i.e., >1 node of injury) to Cry3Bb1 corn from western corn rootworm is associated with rootworm abundance, root injury, and levels of resistance in neighboring fields. To address this question, fields with a history of greater-than-expected injury to Cry3Bb1 corn (focal fields) and surrounding fields (< 2.2 km from focal fields) were examined to quantify rootworm abundance, root injury, and resistance to Cry3Bb1 corn. Additionally, use of Bt corn and soil insecticide use for the previous six years were quantified for each field. Resistance to Cry3Bb1 was present in all fields assayed, even though focal fields had grown more Cry3 corn and less non-Bt corn than surrounding fields. This finding implies that some movement of resistance alleles had occurred between focal fields and surrounding fields. Overall, our data suggest that resistance to Cry3Bb1 in the landscape has been influenced by both local rootworm movement and field-level management tactics.


Assuntos
Endotoxinas/genética , Resistência a Inseticidas/genética , Zea mays/genética , Animais , Bacillus thuringiensis/genética , Bacillus thuringiensis/metabolismo , Besouros/crescimento & desenvolvimento , Produtos Agrícolas/genética , Genes Bacterianos , Larva/crescimento & desenvolvimento , Controle Biológico de Vetores , Raízes de Plantas , Plantas Geneticamente Modificadas
7.
PLoS One ; 15(8): e0238057, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32845917

RESUMO

Arthropods are a major soil fauna group, and have the potential to substantially influence the spatial and temporal variability of soil greenhouse gas (GHG) sinks and sources. The overall effect of soil-inhabiting arthropods on soil GHG fluxes still remains poorly quantified since the majority of the available data comes from laboratory experiments, is often controversial, and has been limited to a few species. The main objective of this study was to provide first insights into field-level carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) release of soil-inhabiting larvae of the Scarabaeidae family. Larvae of the genus Melolontha were excavated at various sites in west-central and southern Germany, covering a wide range of different larval developmental stages, larval activity levels, and vegetation types. Excavated larvae were immediately incubated in the field to measure their GHG production. Gaseous carbon release of individual larvae showed a large inter- and intra-site variability which was strongly correlated to larval biomass. This correlation persisted when upscaling individual CO2 and CH4 production to the plot scale. Field release estimates for Melolontha spp. were subsequently upscaled to the European level to derive the first regional GHG release estimates for members of the Scarabaeidae family. Estimates ranged between 10.42 and 409.53 kt CO2 yr-1, and 0.01 and 1.36 kt CH4 yr-1. Larval N2O release was only sporadically observed and not upscaled. For one site, a comparison of field- and laboratory-based GHG production measurements was conducted to assess potential biases introduced by transferring Scarabaeidae larvae to artificial environments. Release strength and variability of captive larvae decreased significantly within two weeks and the correlation between larval biomass and gaseous carbon production disappeared, highlighting the importance of field measurements. Overall, our data show that Scarabaeidae larvae can be significant soil GHG sources and should not be neglected in soil GHG flux research.


Assuntos
Besouros/metabolismo , Gases de Efeito Estufa/análise , Animais , Biomassa , Dióxido de Carbono/análise , Dióxido de Carbono/metabolismo , Besouros/química , Besouros/crescimento & desenvolvimento , Gases de Efeito Estufa/metabolismo , Larva/química , Larva/metabolismo , Metano/análise , Metano/metabolismo , Óxido Nitroso/análise , Óxido Nitroso/metabolismo , Solo/química , Solo/parasitologia
8.
Chemosphere ; 259: 127497, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32650168

RESUMO

Heavy metal pollution is an increasingly serious problem in agricultural ecosystems. Zinc accumulation in the food chain may harm the physiological functions of organisms, including herbivorous and predatory insects. Its effects on development and reproduction in Harmonia axyridis are largely unknown. In this study, five Zn solutions (25, 50, 100, and 150 mg/kg) plus control (0 mg/kg) were used to treat broad beans and to water the resulting seedlings. Aphids fed on these seedlings were eaten by H. axyridis ladybugs. Zn accumulation was found at all three trophic levels. Compared with the control group, ladybugs in the 25, 50, and 100 mg/kg groups had significantly reduced weight gain from the 4th instar to adulthood. Pupae and larvae (instars 1-4) in the 150 mg/kg group had the lowest survival of any group; pupal mortality in the 100 mg/kg group was significantly higher than that in the control group. Under Zn stress, female adults had inhibited expression of Vg1, Vg2 and VgR, reducing egg production and hatchability. Zn thus negatively affected their fertility. These results provide a theoretical basis for future exploration of soil heavy metal pollution impacts in ecosystems.


Assuntos
Afídeos/química , Besouros/efeitos dos fármacos , Poluentes Ambientais/farmacologia , Fertilidade/efeitos dos fármacos , Cadeia Alimentar , Zinco/farmacologia , Animais , Afídeos/metabolismo , Besouros/crescimento & desenvolvimento , Besouros/metabolismo , Besouros/fisiologia , Relação Dose-Resposta a Droga , Poluentes Ambientais/metabolismo , Feminino , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Masculino , Metais Pesados/metabolismo , Metais Pesados/farmacologia , Plantas Comestíveis/química , Plantas Comestíveis/parasitologia , Reprodução/efeitos dos fármacos , Zinco/metabolismo
9.
Arch Insect Biochem Physiol ; 105(1): e21721, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32557787

RESUMO

The alligator weed flea beetle, Agasicles hygrophila is a monophagous natural enemy of the invasive alligator weed Alternanthera philoxeroides. Oogenesis plays a vital role in the process of individual development and population continuation of oviparous insects. Sox is an ancient and ubiquitous metazoan gene family that plays a key regulatory role in various physiological processes, including oogenesis, which is closely related to fecundity. In this study, two Sox genes AhDichaete and AhSox3 were cloned and characterized, and then the expression profiles of AhDichaete and AhSox3 were qualified by a quantitative reverse transcription-polymerase chain reaction. The result showed that these two Sox genes were expressed significantly higher in ovary, especially in the adult developmental stage. Furthermore, the functions of AhDichaete and AhSox3 in A. hygrophila females were studied using RNA interference (RNAi). Fewer offsprings were produced when AhDichaete and AhSox3 RNAi females mated with wild-type males. Moreover, dsAhSox3 injection reduced the hatching rate of eggs but injection with dsAhDichaete did not. Further study of the reproductive system of AhDichaete and AhSox3 RNAi females showed that yolk protein deposition reduction in the ovarioles, then the expression of vitellogenin gene AhVg2 in ovaries was decreased. These results indicate that AhDichaete and AhSox3 play an important regulatory role in the process of ovarian development and oogenesis by affecting yolk synthesis in the ovary of A. hygrophila.


Assuntos
Besouros/genética , Proteínas de Insetos/genética , Oogênese/genética , Fatores de Transcrição SOX/genética , Animais , Besouros/crescimento & desenvolvimento , Feminino , Proteínas de Insetos/metabolismo , Ovário/crescimento & desenvolvimento , Fatores de Transcrição SOX/metabolismo , Análise de Sequência de DNA
10.
Arch Insect Biochem Physiol ; 104(4): e21685, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32350927

RESUMO

The Colorado potato beetle (CPB; Leptinotarsa decemlineata) is one of the most notorious and difficult to control pests of potato and other solanaceous crops in North America. This insect has evolved a remarkable ability to detoxify both plant and synthetic toxins, allowing it to feed on solanaceous plants containing toxic alkaloids and to develop resistance to synthetic chemicals used for its control. RNA interference (RNAi) is a natural mechanism that evolved as an immune response to double-stranded RNA (dsRNA) viruses where dsRNA triggers silencing of target gene expression. RNAi is being developed as a method to control CPB. Here, we evaluated four CPB-specific genes to identify targets for RNAi-mediated control of this insect. Out of the four dsRNAs evaluated in CPB larvae and adults, dsIAP (dsRNA targeting inhibitor of apoptosis, iap gene) performed better than dsActin, dsHSP70, and dsDynamin in inducing larval mortality. However, in adults, the mortality induced by dsActin is significantly higher than the mortality induced by dsIAP, dsHSP70, and dsDynamin. Interestingly, a combination of dsIAP and dsActin performed better than either dsIAP or dsActin alone by inducing feeding inhibition in 24 hr and mortality in 48 hr in larvae. When the dsIAP and dsActin were expressed in the Escherichia coli HT115 strain and applied as a heat-killed bacterial spray on potato plants, it protected the plants from CPB damage. These studies show that the combination of dsIAP and dsActin shows promise as an insecticide to control CPB.


Assuntos
Besouros/genética , Proteínas Inibidoras de Apoptose/genética , Interferência de RNA , Actinas/genética , Animais , Besouros/efeitos dos fármacos , Besouros/crescimento & desenvolvimento , Escherichia coli , Controle de Insetos/métodos , Proteínas de Insetos/genética , Larva/efeitos dos fármacos , RNA de Cadeia Dupla , Solanum tuberosum
11.
Gene ; 751: 144779, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32428697

RESUMO

In insects, nuclear receptors (NRs) including EcR (NR1H1), USP (NR2B4), E75 (NR1D3), HR3 (NR1F), HR4 (NR6) and FTZ-F1 (NR5A3) mediate the 20-hydroxyecdysone (20E) signaling cascade to play a critical role during larval metamorphosis. In this present paper, we focused on hormone receptor 38 (HR38) in Leptinotarsa decemlineata, the only insect homolog of the NR4A subclass. RNA interference (RNAi) of LdHR38 in the penultimate (third) instar larvae reduced the expression of an ecdysteroidogenesis gene and declined the titer of 20E. Knockdown of LdHR38 intensified the expression of LdUSP, LdE75, LdE74, LdE93, LdBroad and LdHR3, whereas repressed the transcription of LdFTZ-F1. Disruption of 20E signaling inhibited chitin biosynthesis in the larval cuticle. Approximately 25% of the LdHR38 RNAi larvae died, around 40% of the resultant larvae remained as prepupae or become deformed pupae. The body surface of the HR38 depleted abnormal prepupae and pupae looked wet, just like the cuticle being covered with a layer of liquid. Moreover, the increase of larval mortality, and the impairment of pupation and emergence exhibited dose-dependent manners. Furthermore, silencing LdHR38 at the final (fourth) instar caused similar but less severe impairment of pupation. Dietary supplement with 20E for the third instar larvae did not rescue the high larval death and only slightly alleviated the low pupation rate in the LdHR38 RNAi hypomorphs. Accordingly, we propose that HR38 is necessary for tune of ecdysteroidogenesis and for mediation of 20E signaling during metamorphosis in L. decemlineata.


Assuntos
Besouros/crescimento & desenvolvimento , Proteínas de Insetos/fisiologia , Metamorfose Biológica , Receptores Citoplasmáticos e Nucleares/fisiologia , Animais , Quitina/biossíntese , Besouros/genética , Besouros/metabolismo , Ecdisterona/fisiologia , Proteínas de Insetos/antagonistas & inibidores , Proteínas de Insetos/genética , Larva/genética , Larva/crescimento & desenvolvimento , Larva/metabolismo , Pupa/genética , Pupa/crescimento & desenvolvimento , Pupa/metabolismo , Interferência de RNA , Receptores Citoplasmáticos e Nucleares/antagonistas & inibidores , Receptores Citoplasmáticos e Nucleares/genética , Transdução de Sinais
12.
Arch Insect Biochem Physiol ; 104(4): e21680, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32346914

RESUMO

The cigarette beetle (CB; Lasioderma serricorne) is a pest on many stored products including tobacco. Fumigation is the common control method currently used. However, the options for controlling this pest are limited, due to resistance issues and phasing out of currently used chemical insecticides. Here, we evaluated RNA interference (RNAi) as a potential method for controlling the CB. RNA isolated from different stages was sequenced and assembled into a transcriptome. The CB RNA sequences showed the highest homology with those in the red flour beetle, Tribolium castaneum. Orthologs of proteins known to function in RNAi pathway were identified in the CB transcriptome, suggesting that RNAi may work well in this insect. Also, 32 P-labeled double-stranded RNA (dsRNA) injected into CB larvae and adults was processed to small interference RNAs. We selected 12 genes that were shown to be the effective RNAi targets in T. castaneum and other insects and identified orthologs of them in the CB by searching its transcriptome. Injection of dsRNA targeting genes coding for GAWKY, Kinesin, Sec23, SNF7, and 26S proteasome subunit 6B into the CB larvae caused 100% mortality. Feeding dsRNA targeting SNF7 and 26S proteasome subunit 6B by sucrose droplet assay induced more than 90% mortality, which is 1.8 times higher than the mortality induced by dsGFP control (53%). These data demonstrate an efficient RNAi response in CB, suggesting that RNAi could be developed as an efficient method to control this pest.


Assuntos
Besouros/genética , Interferência de RNA , RNA de Cadeia Dupla/genética , Animais , Besouros/crescimento & desenvolvimento , Proteínas de Insetos/genética , Larva/genética , RNA Interferente Pequeno , Transcriptoma
13.
Arch Insect Biochem Physiol ; 104(4): e21679, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32297387

RESUMO

The Asian long-horned beetle (ALB) Anoplophora glabripennis is a serious invasive forest pest in several countries, including the United States. Methods available to manage or eradicate this pest are extremely limited, but RNA interference (RNAi) technology is a potentially effective method to control ALB. In this study, we used sucrose feeding bioassay for oral delivery of double-strand RNA (dsRNA) to ALB larvae. 32 P-labeled dsRNA orally delivered to ALB larvae using the sucrose droplet feeding method was processed to small interfering RNA. Feeding neonate larvae with dsRNA targeting genes coding for the inhibitor of apoptosis (IAP), vacuolar sorting protein SNF7 (SNF7), and snakeskin (SSK) induced knockdown of target genes and mortality. Feeding 2 µg of dsRNA per day for 3 days did not induce a significant decrease in the expression of target genes or mortality. However, feeding 5 or 10 µg of dsRNA per day for 3 days induced a significant decrease in the expression of target genes and 50-90% mortality. Interestingly, feeding 2.5 µg each of dsIAP plus dsSNF7, dsIAP plus dsSSK, or dsSNF7 plus dsSSK per day for 3 days induced a significant decrease in the expression of both target genes and approximately 80% mortality. Our findings demonstrate that orally delivered dsRNA induces target gene knockdown and mortality in ALB neonate larvae and RNAi technology may have the potential for effective ALB control.


Assuntos
Besouros/genética , Interferência de RNA , RNA de Cadeia Dupla , Administração Oral , Animais , Besouros/crescimento & desenvolvimento , Técnicas de Silenciamento de Genes , Proteínas Inibidoras de Apoptose/genética , Controle de Insetos , Proteínas de Insetos/genética , Larva/genética , Larva/crescimento & desenvolvimento
14.
Int J Mol Sci ; 21(7)2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32244803

RESUMO

Chitin deacetylases (CDAs) are chitin-modifying enzymes known to play vital roles in insect metamorphosis and development. In this study, we identified and characterized a chitin deacetylase 1 gene (LsCDA1) from the cigarette beetle Lasioderma serricorne. LsCDA1 contains a 1614 bp open reading frame encoding a protein of 537 amino acids that includes domain structures typical of CDAs. LsCDA1 was mainly expressed in the late larval and late pupal stages. In larval tissues, the highest level of LsCDA1 was detected in the integument. The expression of LsCDA1 was induced by 20-hydroxyecdysone (20E) in vivo, and it was significantly suppressed by knocking down the expression of ecdysteroidogenesis genes and 20E signaling genes. RNA interference (RNAi)-aided silencing of LsCDA1 in fifth-instar larvae prevented the larval-pupal molt and caused 75% larval mortality. In the late pupal stage, depletion of LsCDA1 resulted in the inhibition of pupal growth and wing abnormalities, and the expression levels of four wing development-related genes (LsDY, LsWG, LsVG, and LsAP) were dramatically decreased. Meanwhile, the chitin contents of LsCDA1 RNAi beetles were significantly reduced, and expressions of three chitin synthesis pathway genes (LsTRE1, LsUAP1, and LsCHS1) were greatly decreased. The results suggest that LsCDA1 is indispensable for larval-pupal and pupal-adult molts, and that it is a potential target for the RNAi-based control of L. serricorne.


Assuntos
Amidoidrolases/genética , Besouros/genética , Proteínas de Insetos/genética , Metamorfose Biológica/genética , Muda/genética , Amidoidrolases/classificação , Amidoidrolases/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Quitina/metabolismo , Besouros/enzimologia , Besouros/crescimento & desenvolvimento , Ecdisterona/farmacologia , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Proteínas de Insetos/metabolismo , Larva/enzimologia , Larva/genética , Larva/crescimento & desenvolvimento , Filogenia , Pupa/enzimologia , Pupa/genética , Pupa/crescimento & desenvolvimento , Interferência de RNA , Asas de Animais/anormalidades , Asas de Animais/metabolismo
15.
Sci Rep ; 10(1): 5194, 2020 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-32251305

RESUMO

Explorative experiments were done to figure out differences in the emission of volatile organic compounds (VOCs) of not infested trees and trees infested by Anoplophora glabripennis (Asian longhorn beetle, ALB), a quarantine pest. Therefore, VOCs from some native insect species, Anoplophora glabripennis infested Acer, stressed Acer, healthy Acer, Populus and Salix were obtained by enrichment on adsorbents. Qualitative analysis was done by thermal desorption gas chromatography coupled with a mass selective detector (TD-GC/MS). Altogether 169 substances were identified. 11 substances occur from ALB infested or mechanically damaged trees i.e. stressed trees, but not from healthy trees. (+)-Cyclosativene, (+)-α-longipinene, copaene and caryophyllene are detectable only from ALB-infested Acer not from mechanically damaged or healthy Acer. However, these substances are also emitted by healthy Salix. 2,4-Dimethyl-1-heptene is among all tree samples exclusively present in the ambience of ALB-infested trees. It´s rarely detectable from native insect species' samples.


Assuntos
Acer/química , Besouros , Doenças das Plantas , Populus/química , Salix/química , Compostos Orgânicos Voláteis/análise , Ar/análise , Animais , Besouros/crescimento & desenvolvimento , Cromatografia Gasosa-Espectrometria de Massas , Larva , Oviposição
16.
Sci Rep ; 10(1): 5572, 2020 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-32221344

RESUMO

Disturbances are intrinsic drivers of structure and function in ecosystems, hence predicting their effects in forest ecosystems is essential for forest conservation and/or management practices. Yet, knowledge regarding belowground impacts of disturbance events still remains little understood and can greatly vary by taxonomic and functional identity, disturbance type and local environmental conditions. To address this gap in knowledge, we conducted a survey of soil-dwelling Protura, across forests subjected to different disturbance regimes (i.e. windstorms, insect pest outbreaks and clear-cut logging). We expected that the soil proturan assemblages would differ among disturbance regimes. We also hypothesized that these differences would be driven primarily by variation in soil physicochemical properties thus the impacts of forest disturbances would be indirect and related to changes in food resources. To verify that sampling included two geographically distant subalpine glacial lake catchments that differed in underlying geology, each having four different types of forest disturbance, i.e. control, bark beetle outbreak (BB), windthrow + BB (wind + BB) and clear-cut. As expected, forest disturbance had negative effects on proturan diversity and abundance, with multiple disturbances having the greatest impacts. However, differences in edaphic factors constituted a stronger driver of variability in distribution and abundance of proturans assemblages. These results imply that soil biogeochemistry and resource availability can have much stronger effects on proturan assemblages than forest disturbances.


Assuntos
Artrópodes/crescimento & desenvolvimento , Animais , Biodiversidade , Besouros/crescimento & desenvolvimento , Conservação dos Recursos Naturais , Ecossistema , Florestas , Lagos , Solo , Árvores/fisiologia
17.
Sci Rep ; 10(1): 4970, 2020 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-32188924

RESUMO

Ongoing climate change results in increasing temperatures throughout the seasons. The effects of climate change on insect performance are less studied during the winter season than during the growing season. Here, we investigated the effects of various winter temperature regimes (warm, normal and cold) on the winter performance of the invasive ladybird Harmonia axyridis (Coleoptera: Coccinellidae). Winter survival, body mass loss and post-winter starvation resistance were measured for a laboratory-reared population as well as three populations collected from the field prior to overwintering. The warm winter regime increased the survival rate and body mass loss and reduced post-winter starvation resistance compared to those of the ladybirds in the cold winter regime. The effects of the temperature regime were qualitatively similar for the laboratory-reared and field-collected beetles; however, there were significant quantitative differences in all measured overwintering parameters between the laboratory-reared and field-collected populations. The winter survival of the laboratory-reared beetles was much lower than that of the field-collected beetles. The laboratory-reared beetles also lost a larger proportion of their body mass and had reduced post-winter starvation resistance. Winter survival was similar between the females and males, but compared to the males, the females lost a smaller proportion of their body mass and had better post-winter starvation resistance. The pre-overwintering body mass positively affected winter survival and post-winter starvation resistance in both the laboratory-reared and field-collected ladybirds. The significant differences between the laboratory-reared and field-collected individuals indicate that quantitative conclusions derived from studies investigating solely laboratory-reared individuals cannot be directly extrapolated to field situations.


Assuntos
Índice de Massa Corporal , Temperatura Baixa , Besouros/crescimento & desenvolvimento , Dinâmica Populacional , Estações do Ano , Inanição , Aclimatação , Animais , Feminino , Masculino
18.
Environ Toxicol Chem ; 39(4): 863-872, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32181912

RESUMO

It is often difficult to compare studies examining the effects of endectocides on dung fauna because of different experimental approaches, for example, active ingredients (eprinomectin, doramectin, ivermectin, moxidectin) and formulations (injectable, pour-on, spiked). To gain a better understanding, we performed a quantitative meta-analysis using 22 studies to assess the overall effect of endectocide residues on the occurrence (presence or absence) and abundance of aphodiine dung beetles. Our results document a positive effect on the occurrence of adult beetles, indicating that adults tend to be attracted to dung with residues. Conversely, larvae are less likely to occur in the presence of residues. Thus, either adults that colonize dung with residues do not lay eggs or, more likely, the larvae that hatch from these eggs die early in development. Abundance of adult and larval stages was shown to be significantly reduced in dung containing residues. When individual endectocides were compared, only ivermectin demonstrated a significantly negative effect on the abundance of both adults and larvae, possibly owing to a small sample size for other agents. In laboratory studies, only dung "spiked" with endectocides reduced the abundance of larvae, whereas during field research, only pour-on applications were shown to reduce the abundance of larvae. The present study further documents the nontarget effects of endectocide residues on dung-dwelling organisms, provides robust evidence on the consequences of different application methods, and emphasizes the need for standardized methodological techniques in future studies. Environ Toxicol Chem 2020;39:863-872. © 2020 SETAC.


Assuntos
Besouros/efeitos dos fármacos , Resíduos de Drogas/toxicidade , Poluentes Ambientais/toxicidade , Ivermectina/análogos & derivados , Drogas Veterinárias/toxicidade , Animais , Besouros/crescimento & desenvolvimento , Resíduos de Drogas/análise , Poluentes Ambientais/análise , Fezes/química , Ivermectina/análise , Ivermectina/toxicidade , Larva/efeitos dos fármacos , Gado , Drogas Veterinárias/análise
19.
PLoS One ; 15(2): e0228817, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32032382

RESUMO

Abamectin is a common biocide used to control agricultural insect pests. However, the water insolubility of abamectin may result in extra organic solvent introduced in the environment. To solve this issue, it is desirable to develop nanoformulations to encapsulate abamectin with environment-friendly polymers. In this study, two polylactic acid based abamectin nanoformulations were prepared. The average particle sizes, measured by dynamic light scattering and transmission electron microscope, were 240 nm and 150 nm, respectively. The insecticidal activity of these nano-formulated abamectin was examined in the laboratory on the pea aphid, Acyrthosiphon pisum (Hemiptera: Aphididae). The acute toxicity of nano-formulated abamectin on non-target aphid predator Adalia bipunctata (Coleoptera: Coccinellidae) was also evaluated by topical, residual and oral exposure. The two nano-formulated abamectin had comparable insecticidal effect with commercial abamectin formulation against the pea aphid. Taking median lethal concentration (LC50) as the toxicological endpoint, nanoformulations had higher contact toxicity and lower oral toxicity to first-instar larvae of the predator A. bipunctata. These results are expected to contribute to the application of solvent-free nano-formulated pesticides that comply with the integrated pest management (IPM) strategies.


Assuntos
Afídeos/efeitos dos fármacos , Besouros/efeitos dos fármacos , Inseticidas/toxicidade , Ivermectina/análogos & derivados , Nanoestruturas/química , Poliésteres/química , Animais , Afídeos/crescimento & desenvolvimento , Besouros/crescimento & desenvolvimento , Composição de Medicamentos , Inseticidas/química , Ivermectina/química , Ivermectina/toxicidade , Dose Letal Mediana , Tamanho da Partícula
20.
Bull Entomol Res ; 110(4): 497-505, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32000866

RESUMO

Irradiation is a physical, environmentally friendly treatment which does not leave any residues in the product. It is increasingly used as an alternative to methyl bromide and other chemical fumigants for disinfestation of insect pest in stored grains. In this research, we try to evaluate the effect of low gamma irradiation doses in the range of 50-1200 Gy on the different stages of Callosobruchus maculatus. It was found that no adults emerged after irradiation of eggs at 450 Gy. No emerging adults (F1 generation) have been shown when larvae or pupae were exposed to 650 Gy. Also, no emerging adult has been shown from the parental C. maculatus adults irradiated with 650 Gy. When suppression of F1 generation was used for the measuring effective irradiation dose and phytosanitary efficacy, 650 Gy was required for disinfestation of cowpea seed weevils. The irradiation dose level of 650 Gy was used for the large-scale confirmatory tests applied to 27,754 adults of C. maculatus in cowpea seeds resulting in non F1 adults' production with a confidence level of 93.77%. All the physical and chemical characteristics of cowpea seeds were non-significantly (P ≤ 0.05) affected by the irradiation dose of 650 Gy. Meanwhile, this irradiation dose very slightly reduced the microbial load of cowpea seeds. We recommend the generic dose 650 Gy as the phytosanitary irradiation dose for the cowpea seed weevil.


Assuntos
Besouros/efeitos da radiação , Vigna/efeitos da radiação , Animais , Besouros/crescimento & desenvolvimento , Feminino , Raios gama/efeitos adversos , Controle de Insetos , Larva/efeitos da radiação , Masculino , Óvulo/efeitos da radiação , Pupa/efeitos da radiação , Sementes/efeitos da radiação
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