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1.
Prog Chem Org Nat Prod ; 116: 37-66, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34698945

RESUMO

The interdisciplinary field of Chemical Ecology in Brazil is currently composed of groups that emerged through the pioneering studies of Keith Spalding Brown Jr. and José Tércio Barbosa Ferreira. Following Keith Brown 's steps, José Roberto Trigo continued investigating the role of plant natural products in mediating the association among insects and their host plants, mainly in the Order Lepidoptera. The role of pyrrolizidine alkaloids in those associations was investigated extensively by Brown and Trigo, and most of what is currently known on this subject is based on their studies. The present work acknowledges their contribution to the Brazilian chemical ecology field and on insect-plant communication studies mediated by different chemical compounds.


Assuntos
Lepidópteros , Alcaloides de Pirrolizidina , Animais , Brasil , Ecologia , Plantas
2.
PLoS One ; 16(9): e0257925, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34591899

RESUMO

Tuta absoluta is one of the most damaging pests of tomato crops worldwide. Damage due to larvae may cause up to 100% loss of tomato production. Use of natural enemies to control the pest, notably predatory mirids such as Nesidiocoris tenuis and Macrolophus pygmaeus, is increasingly being promoted. However, considering the potential damage caused to tomatoes by these omnivorous predators in the absence of T. absoluta, an alternative solution could be required to reduce tomato damage and improve the predators' performance. The use of companion plants can be an innovative solution to cope with these issues. The present study aimed to determine the influence of companion plants and alternative preys on the predators' performance in controlling T. absoluta and protecting tomato plants. We evaluated the effect of predators (alone or combined) and a companion plant (sesame (Sesamum indicum)) on T. absoluta egg predation and crop damage caused by N. tenuis. The influence of an alternative prey (Ephestia kuehniella eggs) on the spatial distribution of predators was also evaluated by caging them in the prey presence or absence, either on tomato or sesame plants or on both. We found that the presence of sesame did not reduce the efficacy of N. tenuis or M. pygmaeus in consuming T. absoluta eggs; hatched egg proportion decreased when N. tenuis, M. pygmaeus, or both predators were present. More specifically, this proportion was more strongly reduced when both predators were combined. Sesame presence also reduced necrotic rings caused by N. tenuis on tomato plants. Nesidiocoris tenuis preferred sesame over tomato plants (except when food was provided only on the tomato plant) and the upper part of the plants, whereas M. pygmaeus preferred tomato to sesame plants (except when food was provided only on the sesame plant) and had no preference for a plant part. Combination of predators N. tenuis and M. pygmaeus allows for better coverage of cultivated plants in terms of occupation of different plant parts and better regulation of T. absoluta populations. Sesamum indicum is a potential companion plant that can be used to significantly reduce N. tenuis damage to tomatoes.


Assuntos
Heterópteros/fisiologia , Lepidópteros/patogenicidade , Lycopersicon esculentum/crescimento & desenvolvimento , Sesamum/crescimento & desenvolvimento , Animais , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/parasitologia , Larva/fisiologia , Lepidópteros/parasitologia , Lycopersicon esculentum/parasitologia , Controle Biológico de Vetores , Componentes Aéreos da Planta/crescimento & desenvolvimento , Componentes Aéreos da Planta/parasitologia , Comportamento Predatório , Sesamum/parasitologia
3.
Int J Mol Sci ; 22(15)2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34360963

RESUMO

The insect immune response is initiated by the recognition of invading microorganisms. Peptidoglycan recognition proteins (PGRPs) function primarily as pattern recognition receptors by specifically binding to peptidoglycans expressed on microbial surfaces. We cloned a full-length cDNA for a PGRP from the Asian corn borer Ostrinia furnacalis (Guenée) and designated it as PGRP1. PGRP1 mRNA was mainly detected in the fat bodies and hemocytes. Its transcript levels increased significantly upon bacterial and fungal challenges. Purified recombinant PGRP1 exhibited binding activity to the gram-positive Micrococcus luteus, gram-negative Escherichia coli, entomopathogenic fungi Beauveria bassiana, and yeast Pichia pastoris. The binding further induced their agglutination. Additionally, PGRP1 preferred to bind to Lys-type peptidoglycans rather than DAP-type peptidoglycans. The addition of recombinant PGRP1 to O. furnacalis plasma resulted in a significant increase in phenoloxidase activity. The injection of recombinant PGRP1 into larvae led to a significantly increased expression of several antimicrobial peptide genes. Taken together, our results suggest that O. furnacalis PGRP1 potentially recognizes the invading microbes and is involved in the immune response in O. furnacalis.


Assuntos
Imunidade Inata , Proteínas de Insetos/metabolismo , Lepidópteros/genética , Peptidoglicano/metabolismo , Animais , Beauveria/patogenicidade , Corpo Adiposo/metabolismo , Hemócitos/metabolismo , Proteínas de Insetos/genética , Lepidópteros/imunologia , Lepidópteros/microbiologia , Micrococcus luteus/patogenicidade , Monofenol Mono-Oxigenase/metabolismo , Peptidoglicano/genética , Proteínas Citotóxicas Formadoras de Poros/genética , Proteínas Citotóxicas Formadoras de Poros/metabolismo , Saccharomycetales/patogenicidade
4.
Planta ; 254(3): 61, 2021 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-34455499

RESUMO

MAIN CONCLUSION: Extensive histology of host organs revealed the early events in the vegetative growth of Rafflesia consueloae including initial infection site, endophyte distribution, and other developmental events prior to bud emergence. The early events in the vegetative development of the holoparasite Rafflesia have long remained a mystery. Because its entire vegetative growth occurs within the host body, very little is known about the developmental events prior to emergence of the floral shoot. The goal of this study was to describe the events that occur during the vegetative growth of R. consueloae, particularly in the early stages of infection. We performed extensive microtome sectioning of multiple root and stem segments from different Tetrastigma host individuals to examine the cytology, distribution, and development of the R. consueloae endophyte within the host tissues. We found that R. consueloae infection is restricted to the roots of its host. Infection begins within the vascular cambium where the endophyte appears to initially reside prior to their radial spread to the vascular tissues. The tissues obtained from different host individuals had varying degrees of infection alluding to a possible role of host resistance mechanisms and/or varying levels of parasite infectiousness. Endophyte presence in host vines without external manifestations of infection indicates that the parasite may dwell within the host tissues for prolonged periods as small cell clusters without transitioning to the reproductive stage. Furthermore, we found that floral shoots may develop in scarcely infected host tissues indicating that extensive endophyte growth within the host is not a prerequisite to the onset of reproductive development. Overall, our study describes for the first time the developmental events prior to emergence of R. consueloae buds from its host.


Assuntos
Lepidópteros , Parasitos , Animais , Câmbio , Endófitos , Reprodução
5.
Sci Rep ; 11(1): 16657, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34404858

RESUMO

While walking on horizontal substrates, caterpillars skilfully engage all their legs, including three pairs of thoracic legs and a maximum of five pairs of prolegs, to move in a flexible wave-like motion. Such locomotory behaviours, represented by 'crawling' and 'inching' motions, have widely inspired the development of locomotion systems in soft robotics. However, bagworms are unable to use their prolegs for walking because these are always accommodated in a portable bag; thus, they are unable to walk using such general locomotory behaviours. Indeed, how they walk with only three pairs of thoracic legs is unknown at present. In this study, we show that bagworms construct a ladder-like foothold using their silk to walk without using prolegs. This enables them to walk not only on horizontal floor surfaces but also on wall and ceiling surfaces, even those with slippery or smooth surfaces. They construct the foothold by spinning a continuous silk thread in a zigzag manner and controlling the discharge of adhesive to attach the folded parts of the silk to a substrate. Discovery of this elaborate silk utilisation technique offers fresh insights into the diversity of silk use in lepidopteran larvae and provides potential designs for robot locomotion systems.


Assuntos
Lepidópteros/fisiologia , Seda/metabolismo , Adesivos/metabolismo , Animais , Biomimética , Feminino , Larva/anatomia & histologia , Larva/fisiologia , Lepidópteros/anatomia & histologia , Locomoção , Masculino , Robótica
6.
Sci Rep ; 11(1): 15956, 2021 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-34354186

RESUMO

The soybean technology MON 87701 × MON 89788, expressing Cry1Ac and conferring tolerance to glyphosate, has been widely adopted in Brazil since 2013. However, pest shifts or resistance evolution could reduce the benefits of this technology. To assess Cry1Ac soybean performance and understand the composition of lepidopteran pest species attacking soybeans, we implemented large-scale sampling of larvae on commercial soybean fields during the 2019 and 2020 crop seasons to compare with data collected prior to the introduction of Cry1Ac soybeans. Chrysodeixis includens was the main lepidopteran pest in non-Bt fields. More than 98% of larvae found in Cry1Ac soybean were Spodoptera spp., although the numbers of Spodoptera were similar between Cry1Ac soybean and non-Bt fields. Cry1Ac soybean provided a high level of protection against Anticarsia gemmatalis, C. includens, Chloridea virescens and Helicoverpa spp. Significant reductions in insecticide sprays for lepidopteran control in soybean were observed from 2012 to 2019. Our study showed that C. includens and A. gemmatalis continue to be primary lepidopteran pests of soybean in Brazil and that Cry1Ac soybean continues to effectively manage the target lepidopteran pests. However, there was an increase in the relative abundance of non-target Spodoptera spp. larvae in both non-Bt and Cry1Ac soybeans.


Assuntos
Lepidópteros/genética , Controle Biológico de Vetores/métodos , Soja/genética , Animais , Toxinas de Bacillus thuringiensis/genética , Proteínas de Bactérias/genética , Brasil , Endotoxinas/metabolismo , Proteínas Hemolisinas/genética , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Inseticidas , Larva/efeitos dos fármacos , Lepidópteros/patogenicidade , Mariposas/efeitos dos fármacos , Plantas Geneticamente Modificadas/genética , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo
7.
Sci Rep ; 11(1): 13941, 2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-34230568

RESUMO

Odorant-binding proteins (OBPs) are prevalent in the antennal transcriptomes of different orders of insects. Studies on OBPs have focused on their role in the insect chemosensory system, but knowledge of their functions in the insect testis is limited. We sequenced the transcriptomes of the Athetis dissimilis reproductive organs and analyzed the expression of AdisOBP genes in different tissues. We identified 23 OBPs in the testis and ovaries and 31 OBPs in antennal transcriptomes. The results of real-time quantitative PCR revealed that 23 of the 54 OBP genes were highly expressed in both female and male antennae, including three that exhibited male-biased expression and 15 that exhibited female-biased expression. A total of 24 OBPs were highly expressed in the testis of A. dissimilis, while expression of OBPs in the ovaries was very low. These findings highlight the functional diversity of OBPs in insects and can facilitate further studies on the OBPs in A. dissimilis and lepidopteran species.


Assuntos
Antenas de Artrópodes/metabolismo , Regulação da Expressão Gênica , Genitália/metabolismo , Lepidópteros/genética , Receptores Odorantes/genética , Animais , Feminino , Perfilação da Expressão Gênica , Ontologia Genética , Masculino , Anotação de Sequência Molecular , Ovário/metabolismo , Filogenia , Receptores Odorantes/metabolismo , Análise de Sequência de DNA , Testículo/metabolismo , Transcriptoma/genética
8.
Pest Manag Sci ; 77(11): 5086-5095, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34231946

RESUMO

BACKGROUND: To understand the ongoing resistance of cotton bollworm, Helicoverpa armigera, the sensitivity of five field populations to commonly used insecticides, indoxacarb, abamectin, methoxyfenozide, chlorfenapyr, chlorantraniliprole, spinetoram, lambda-cyhalothrin, carbosulfan, metaflumizone, chlorpyrifos, and flufenoxuron, were evaluated. Furthermore, the biochemical and molecular mechanisms of field-evolved resistance in H. armigera were also investigated. RESULTS: Five field populations of H. armigera showed moderate resistance to indoxacarb, chlorantraniliprole, metaflumizone, methoxyfenozide, carbosulfan and lambda-cyhalothrin. The resistance ratio (RR) of indoxacarb was significantly correlated with glutathione-S-transferases (GSTs) activity (r = 0.913, P = 0.011). Methoxyfenozide RR was largely correlated with cytochrome P450s activity (r = 0.860, P = 0.028). Besides, six cytochrome P450s genes of CYP4L5 in AQP, CYP6B7 and CYP9A14 in HDP and BDP, CYP9A17V2 in HDP and YSP, CYP332A1 in HDP, LFP, AQP and YSP, CYP337B1 in YSP, and two GSTs genes of GSTd1 and GSTs1 in HDP were overexpressed (>5-fold). Moreover, indoxacarb RR was positively correlated with the overexpression of GSTs1, GSTd1 and CYP9A14 genes (r = 0.880, 0.98 and 0.86, P = 0.021, 0.001 and 0.028, respectively). The transcript of CYP9A17V2 and CYP337B1 were found to be correlated with metaflumizone RR (r = 0.950, P = 0.004) and carbosulfan RR (r = 0.850, P = 0.033), respectively. CONCLUSION: H. armigera can be effectively controlled using abamectin, chlorfenapyr, chlorpyrifos and spinetoram in Hebei and Shandong provinces. The present study demonstrated that the relative expression level of GSTs1, GSTd1, CYP9A14, CYP9A17V2 and CYP337B1 genes were significantly correlated with the resistance ratio to indoxacarb, metaflumizone and carbosulfan in field H. armigera.


Assuntos
Inseticidas , Lepidópteros , Mariposas , Animais , Sistema Enzimático do Citocromo P-450/genética , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Mariposas/genética
9.
Int J Mol Sci ; 22(11)2021 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-34198929

RESUMO

The molecular mechanisms of insect resistance to Cry toxins generated from the bacterium Bacillus thuringiensis (Bt) urgently need to be elucidated to enable the improvement and sustainability of Bt-based products. Although downregulation of the expression of midgut receptor genes is a pivotal mechanism of insect resistance to Bt Cry toxins, the underlying transcriptional regulation of these genes remains elusive. Herein, we unraveled the regulatory mechanism of the downregulation of the ABC transporter gene PxABCG1 (also called Pxwhite), a functional midgut receptor of the Bt Cry1Ac toxin in Plutella xylostella. The PxABCG1 promoters of Cry1Ac-susceptible and Cry1Ac-resistant strains were cloned and analyzed, and they showed clear differences in activity. Subsequently, a dual-luciferase reporter assay, a yeast one-hybrid (Y1H) assay, and RNA interference (RNAi) experiments demonstrated that a cis-mutation in a binding site of the Hox transcription factor Antennapedia (Antp) decreased the promoter activity of the resistant strain and eliminated the binding and regulation of Antp, thereby enhancing the resistance of P. xylostella to the Cry1Ac toxin. These results advance our knowledge of the roles of cis- and trans-regulatory variations in the regulation of midgut Cry receptor genes and the evolution of Bt resistance, contributing to a more complete understanding of the Bt resistance mechanism.


Assuntos
Membro 1 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Toxinas de Bacillus thuringiensis/genética , Proteínas de Insetos/genética , Resistência a Inseticidas/genética , Receptores de Superfície Celular/genética , Animais , Bacillus thuringiensis/genética , Endotoxinas/genética , Lepidópteros/efeitos dos fármacos , Lepidópteros/genética , Mutação/genética , Regiões Promotoras Genéticas/genética
11.
Int J Mol Sci ; 22(14)2021 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-34299005

RESUMO

Nanoparticles can interact with the complement system and modulate the inflammatory response. The effect of these interactions on the complement activity strongly depends on physicochemical properties of nanoparticles. The interactions of silver nanoparticles with serum proteins (particularly with the complement system components) have the potential to significantly affect the antibacterial activity of serum, with serious implications for human health. The aim of the study was to assess the influence of graphite oxide (GO) nanocomposites (GO, GO-PcZr(Lys)2-Ag, GO-Ag, GO-PcZr(Lys)2) on the antibacterial activity of normal human serum (NHS), serum activity against bacteria isolated from alveoli treated with nanocomposites, and nanocomposite sensitivity of bacteria exposed to serum in vitro (using normal human serum). Additionally, the in vivo cytotoxic effect of the GO compounds was determined with application of a Galleria mellonella larvae model. GO-PcZr(Lys)2, without IR irradiation enhance the antimicrobial efficacy of the human serum. IR irradiation enhances bactericidal activity of serum in the case of the GO-PcZr(Lys)2-Ag sample. Bacteria exposed to nanocomposites become more sensitive to the action of serum. Bacteria exposed to serum become more sensitive to the GO-Ag sample. None of the tested GO nanocomposites displayed a cytotoxicity towards larvae.


Assuntos
Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Grafite/química , Nanopartículas Metálicas/química , Nanocompostos/química , Óxidos/química , Soro/efeitos dos fármacos , Animais , Antibacterianos/química , Anti-Infecciosos/química , Sobrevivência Celular/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/efeitos da radiação , Humanos , Raios Infravermelhos , Larva/efeitos dos fármacos , Larva/efeitos da radiação , Lepidópteros/efeitos dos fármacos , Lepidópteros/efeitos da radiação , Nanopartículas Metálicas/administração & dosagem , Nanocompostos/administração & dosagem , Soro/microbiologia , Prata/química
12.
Int J Mol Sci ; 22(13)2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-34202141

RESUMO

Intestinal symbiotic bacteria have played an important role in the digestion, immunity detoxification, mating, and reproduction of insects during long-term coevolution. The oriental fruit moth, Grapholita molesta, is an important fruit tree pest worldwide. However, the composition of the G. molesta microbial community, especially of the gut microbiome, remains unclear. To explore the differences of gut microbiota of G. molesta when reared on different host plants, we determined the gut bacterial structure when G. molesta was transferred from an artificial diet to different host plants (apples, peaches, nectarines, crisp pears, plums, peach shoots) by amplicon sequencing technology. The results showed that Proteobacteria and Firmicutes are dominant in the gut microbiota of G. molesta. Plum-feeding G. molesta had the highest richness and diversity of gut microbiota, while apple-feeding G. molesta had the lowest. PCoA and PERMANOVA analysis revealed that there were significant differences in the gut microbiota structure of G. molesta on different diets. PICRUSt2 analysis indicated that most of the functional prediction pathways were concentrated in metabolic and cellular processes. Our results confirmed that gut bacterial communities of G. molesta can be influenced by host diets and may play an important role in host adaptation.


Assuntos
Microbioma Gastrointestinal , Lepidópteros/microbiologia , Análise de Variância , Animais , Biologia Computacional/métodos , Interações Hospedeiro-Parasita , Metagenômica/métodos , Plantas/parasitologia , RNA Ribossômico 16S/genética
13.
J Chem Ecol ; 47(7): 642-652, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34331170

RESUMO

Finding plant cultivars that are resistant or tolerant against lepidopteran pests, takes time, effort and is costly. We present here a high throughput leaf-disk consumption assay system, to screen plants for resistance or chemicals for their deterrence. A webcam capturing images at regular intervals can follow the feeding activities of 150 larvae placed into individual cages. We developed a computer program running under an open source image analysis program to analyze and measure the surface of each leaf disk over time. We further developed new statistical procedures to analyze the time course of the feeding activities of the larvae and to compare them between treatments. As a test case, we compared how European corn borer larvae respond to a commercial antifeedant containing azadirachtin, and to quinine, which is a bitter alkaloid for many organisms. As expected, increasing doses of azadirachtin reduced and delayed feeding. However, quinine was poorly effective at the range of concentrations tested (10-5 M to 10-2 M). The model cage, the camera holder, the plugins, and the R scripts are freely available, and can be modified according to the users' needs.


Assuntos
Bioensaio/métodos , Comportamento Alimentar , Lepidópteros/fisiologia , Animais , Análise por Conglomerados , Comportamento Alimentar/efeitos dos fármacos , Processamento de Imagem Assistida por Computador , Larva/crescimento & desenvolvimento , Larva/fisiologia , Lepidópteros/crescimento & desenvolvimento , Limoninas/farmacologia , Folhas de Planta/química , Folhas de Planta/metabolismo , Quinina/farmacologia , Zea mays/química , Zea mays/metabolismo
14.
Science ; 373(6554): 535-541, 2021 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-34326235

RESUMO

Interkingdom competition occurs between hymenopteran parasitoids and insect viruses sharing the same insect hosts. It has been assumed that parasitoid larvae die with the death of the infected host or as result of competition for host resources. Here we describe a gene family, parasitoid killing factor (pkf), that encodes proteins toxic to parasitoids of the Microgastrinae group and determines parasitism success. Pkfs are found in several entomopathogenic DNA virus families and in some lepidopteran genomes. We provide evidence of equivalent and specific toxicity against endoparasites for PKFs found in entomopoxvirus, ascovirus, baculovirus, and Lepidoptera through a mechanism that elicits apoptosis in the cells of susceptible parasitoids. This highlights the evolutionary arms race between parasitoids, viruses, and their insect hosts.


Assuntos
Entomopoxvirinae/fisiologia , Proteínas de Insetos/toxicidade , Lepidópteros/parasitologia , Lepidópteros/virologia , Proteínas Virais/toxicidade , Vespas/fisiologia , Animais , Apoptose , Evolução Biológica , Transferência Genética Horizontal , Genoma de Inseto , Interações Hospedeiro-Parasita , Proteínas de Insetos/química , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Vírus de Insetos/fisiologia , Larva/genética , Larva/parasitologia , Larva/virologia , Lepidópteros/genética , Lepidópteros/metabolismo , Nucleopoliedrovírus/fisiologia , Spodoptera/genética , Spodoptera/metabolismo , Spodoptera/parasitologia , Spodoptera/virologia , Proteínas Virais/química , Proteínas Virais/genética , Proteínas Virais/metabolismo , Vespas/crescimento & desenvolvimento
15.
Oecologia ; 196(4): 1017-1026, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34322748

RESUMO

The direction and strength of selection for prey colouration by predators vary in space and time and depend on the composition of the predator community. We tested the hypothesis that bird selection pressure on prey colouration changes through the season due to changes in the proportion of naïve juvenile individuals in the bird community, because naïve and educated birds differ in their responses to prey colours. Bird predation on caterpillar-shaped plasticine models in two boreal forest sites increased sevenfold from early summer to mid-summer, and the time of this increase coincides with the fledging of juvenile birds. In early summer, cryptic (black and green) models were attacked at fivefold higher rates compared with conspicuous (red and yellow) models. By contrast, starting from fledging time, cryptic and conspicuous models were attacked at similar rates, hinting at a lower selectivity by naïve juvenile birds compared with educated adult birds. Cryptic models exposed in a group together with conspicuous models were attacked by birds at a threefold lower rate than cryptic models exposed singly, thus supporting the aposematic commensalism hypothesis. However, this effect was not observed in mid- and late summer, presumably due to the lack of avoidance of conspicuous prey by the juvenile birds. We conclude that selection pressure on prey colouration weakens considerably when naïve birds dominate in the community, because the survival advantages of aposematic colouration are temporarily lost for both the conspicuous and their neighbouring cryptic prey.


Assuntos
Aves , Lepidópteros , Animais , Humanos , Comportamento Predatório , Estações do Ano
16.
Artigo em Inglês | MEDLINE | ID: mdl-34082110

RESUMO

High latitude insect populations must cope with extreme conditions, particularly low temperatures. Insects use a variety of cold hardiness mechanisms to withstand this temperature stress, and these can drive geographic distributions through overwintering mortality. The degree of cold hardiness can be altered by two evolved responses: phenotypic plasticity and local adaptation. Phenotypic plasticity can occur within or between generations (transgenerational plasticity; TGP), and local adaptation can evolve through directional selection in response to regional climatic differences. We used the eastern spruce budworm, Choristoneura fumiferana (Lepidoptera: Tortricidae) as a model to explore the role that variable winter temperatures play in inducing two aspects of plasticity in cold hardiness: TGP and local adaptation in phenotypic plasticity. This species is one of the most destructive boreal forest pests in North America, therefore accurately predicting overwintering survival is essential for effective management. While we found no evidence of TGP in cold hardiness, there was a long term fitness cost to larvae that experienced repeated cold exposures. We also found evidence of local adaptation in both seasonal and short-term plasticity of cold hardiness, as our more northerly populations that would experience lower overwintering temperatures had more plastic responses to cold exposure. These findings provide evidence for the importance of phenotypic plasticity and local adaptation when modelling species distributions.


Assuntos
Aclimatação , Temperatura Baixa , Lepidópteros/fisiologia , Estações do Ano , Migração Animal , Animais , Ecologia , Feminino , Geografia , Insetos , Larva , Masculino , América do Norte , Fenótipo , Dinâmica Populacional , Temperatura
17.
J Econ Entomol ; 114(4): 1808-1816, 2021 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-34104958

RESUMO

High population density (crowding) becomes a stress factor in insects. The oriental armyworm, Mythimna separata (Walker), displays gregarious and solitary phases at high and low population densities, respectively. In this study, we compared life history, disease resistance, and induction of antioxidant enzymes and heat shock protein (HSPs) in two phases of M. separata larvae. Results showed that gregarious larvae had a faster growth rate and lower pupal weight compared to solitary larvae. Furthermore, gregarious individuals exhibited higher survival rates than solitary individuals after Beauveria bassiana infection. The gregarious larvae had higher malondialdehyde content compared to solitary ones, but no differences in total antioxidant capacity were observed between the two larval phases before or after infection. Superoxide dismutase and glutathione peroxidase activities were significantly lower in gregarious M. separata larvae than solitary individuals before infection, but no difference was detected in two phases after infection. However, peroxidase and catalase activities in the two phases showed no difference either before or after infection. Hsp19.8 and Hsp90 expression in gregarious larvae were up-regulated when compared to solitary individuals before or after infection. CuZnSOD expression was not different between the two phases before infection, but it was up-regulated in gregarious ones compared to solitary ones after infection. However, expression of other stress-related genes in gregarious larvae was either repressed or unchanged when compared to solitary individuals before or after infection. Thus, larval crowding changed life history, improved disease resistance of M. separata larvae, and induced variable response of antioxidant enzymes and HSPs to fungal infection.


Assuntos
Lepidópteros , Mariposas , Animais , Antioxidantes , Resistência à Doença , Proteínas de Choque Térmico/genética , Larva
18.
J Econ Entomol ; 114(4): 1533-1541, 2021 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-34132348

RESUMO

Monitoring adult populations of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), a major agricultural pest, provides data useful for its control. Food attractants, considered as adult insect behavior regulators based on the preference of an herbivorous pest for food sources or their volatiles, also have great potential for monitoring populations. To study the feasibility of monitoring the population dynamics and reproductive development of H. armigera in the field using food attractants, we quantitatively analyzed reproductive organ development of adults in a laboratory population as a way to predict the reproductive development of adults trapped using food attractants in the field in 2019 and 2020. The adults trapped using food attractants had obvious generational changes and the same trends in variation for females and males. The extent of ovarian development in trapped females tended to increase within each generation, and the major axis length of testis in trapped males tended to decrease. Reproductive developmental status of trapped adults also differed significantly among months. This study shows that by trapping H. armigera with food attractants, the population dynamics of adults in the field can be monitored, and reproductive anatomy can also be used to monitor adult reproductive status. These approaches are a new way to forecast the population dynamics of this pest.


Assuntos
Lepidópteros , Mariposas , Animais , Feminino , Masculino , Dinâmica Populacional , Reprodução
19.
PLoS One ; 16(6): e0249150, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34138865

RESUMO

Two new chimeric Bacillus thuringiensis (Bt) proteins, Cry1A.2 and Cry1B.2, were constructed using specific domains, which provide insecticidal activity against key lepidopteran soybean pests while minimizing receptor overlaps between themselves, current, and soon to be commercialized plant incorporated protectants (PIP's) in soybean. Results from insect diet bioassays demonstrate that the recombinant Cry1A.2 and Cry1B.2 are toxic to soybean looper (SBL) Chrysodeixis includens Walker, velvetbean caterpillar (VBC) Anticarsia gemmatalis Hubner, southern armyworm (SAW) Spodoptera eridania, and black armyworm (BLAW) Spodoptera cosmioides with LC50 values < 3,448 ng/cm2. Cry1B.2 is of moderate activity with significant mortality and stunting at > 3,448 ng/cm2, while Cry1A.2 lacks toxicity against old-world bollworm (OWB) Helicoverpa armigera. Results from disabled insecticidal protein (DIP) bioassays suggest that receptor utilization of Cry1A.2 and Cry1B.2 proteins are distinct from each other and from current, and yet to be commercially available, Bt proteins in soy such as Cry1Ac, Cry1A.105, Cry1F.842, Cry2Ab2 and Vip3A. However, as Cry1A.2 contains a domain common to at least one commercial soybean Bt protein, resistance to this common domain in a current commercial soybean Bt protein could possibly confer at least partial cross resistance to Cry1A2. Therefore, Cry1A.2 and Cry1B.2 should provide two new tools for controlling many of the major soybean insect pests described above.


Assuntos
Toxinas de Bacillus thuringiensis/química , Toxinas de Bacillus thuringiensis/genética , Bacillus thuringiensis/genética , Lepidópteros/fisiologia , Controle Biológico de Vetores , Soja , Animais , Domínios Proteicos , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética
20.
Zootaxa ; 4966(3): 385391, 2021 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-34186608

RESUMO

The subfamily Lypusinae of Korea is reviewed with three species including a new species, Agnoea danguni Sohn, sp. nov. belonging to nominotypical subgenus, and two species of Agnoea belonging to the subgenus Tubuliferodes Toll, 1956: A. (T.) digitiella Kim, 2020 and A. (T.) josephinae (Toll, 1956). The female characters of A. digitiella are described for the first time. Additional collecting records are provided for A. digitiella and A. josephinae. Photographs of the habitus and the genitalia are provided for all three species of Agnoea known so far from Korea.


Assuntos
Lepidópteros/anatomia & histologia , Lepidópteros/classificação , Animais , Feminino , Genitália , República da Coreia
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