Página 1 dos resultados de 15148 itens digitais encontrados em 0.004 segundos

‣ Sequências, propriedades e função de β-1,3-glucanases de insetos; Sequences, properties and function of insect β-1,3-glucanases

Bragatto, Ivan
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 03/10/2011 Português
Relevância na Pesquisa
36.71818%
β-1,3-glucanases são enzimas encontradas em muitos organismos, como fungos, bactéria e plantas. Suas funções incluem remodelamento de parede celular, defesa e digestão. É um alvo interessante para o controle populacional de insetos-praga, porque é ausente em vertebrados. Em insetos, é encontrada no intestino de muitas ordens diferentes, e hidrolizam β-1,3 ou β-1,3(4)-glucanas ingeridas, mas pouco se sabe sobre as propriedades e a função dessas enzimas. Nós estudamos três espécies de insetos, de três ordens diferentes. Spodoptera frugiperda (Lepidoptera), Tenebrio molitor (Coleoptera) e Abracris flavolineata (Orthoptera) são insetos herbívoros e pestes de plantações, mas suas beta-1,3-glucanases diferem significativamente. A β- 1,3-glucanase de S. frugiperda (SLAM) foi purificada do intestino médio da larva. Ela apresenta uma massa molecular de 37,5 kDa, um pH ótimo alcalino de 9,0, é ativa contra β-1,3-glucana (laminarina), mas é incapaz de hidrolizar β-1,3-1,6-glucana de levedura ou outros polisacarídeos. SLAM é não-processiva (0,4), e não é inibida por altas concentrações de substrato. Diferente de outras β-1,3-glucanases digestivas de insetos, SLAM é incapaz de lisar células de Saccharomyces cerevisae. O cDNA correspondente à SLAM foi clonado e sequenciado...

‣ Genes de Bacillus thuringiensis : uma estratégia para conferir resistência a insetos em plantas; Bacillus thuringiensis genes an approach to confer insect resistance to plants

Bobrowski, Vera Lúcia; Fiuza, Lidia Mariana; Pasquali, Giancarlo; Bodanese-Zanettini, Maria Helena
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
Português
Relevância na Pesquisa
36.71818%
Os insetos constituem uma das principais causas de danos à produção agrícola no mundo. O controle de insetos tem sido realizado por meio de agroquímicos e, em muito menor escala, pelo emprego de inseticidas biológicos. As plantas transgênicas resistentes a insetos representam uma nova alternativa no combate aos insetos-praga das lavouras. A bactéria entomopatogênica Bacillus thuringiensis Berlinier (Bt) é a fonte dos genes de resistência nas chamadas plantas-Bt, produzidas comercialmente. No presente trabalho de revisão, são abordados os aspectos relacionados à bactéria Bt como fonte de genes de resistência a insetos-pragas, plantas geneticamente modificadas, vantagens do uso de plantas-Bt, bem como perspectivas dessa ferramenta biotecnológica.; Insect pests are a major worldwide cause of damage to agriculture. The control of insect pests was primarily relied on agrochemical and, in a much smaller scale, on biological insecticides. Insect-resistant transgenic plants represent a new alternative to the protection of crops against insect pests. The entomopathogenic bacterium Bacillus thuringiensis (Bt) is the source of resistance genes for the commercial production of the so called Bt-plants. In this review, the main features of Bt as source of resistance genes will be described as well as the main aspects of insect-resistant transgenic plants and advantages of using Btplants.

‣ A preliminary study of insect fauna on pig carcasses located in sugarcane in winter in southeastern Brazil

Gomes, L.; Gomes, G.; Desuo, I.
Fonte: Wiley-Blackwell Publishing, Inc Publicador: Wiley-Blackwell Publishing, Inc
Tipo: Artigo de Revista Científica Formato: 155-159
Português
Relevância na Pesquisa
36.686753%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 06/50356-2; Minimum post-mortem intervals can be estimated based on analyses of the pattern of insect succession on a carcass. In order to successfully apply this approach, insect development rates must be considered with regard to local regional climatic conditions. This study is the first to analyse insect succession on carcasses decomposing in a sugarcane crop in Brazil. In all seasons, Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae) and Cochliomyia macellaria (Fabricius) were frequent visitors during the fresh and bloated stages of decomposition, whereas Dermestes maculatus (De Geer) (Coleoptera: Dermistdae), Necrobia rufipes (De Geer) (Coleoptera: Cleridae) and Oxelytrum sp. (Coleoptera: Silphidae) were characteristic at the most advanced decomposition stages. The fact that climatic variations influence the occurrence of insect species and vegetation in the tropics may help to solve crimes through sampling of the local insect fauna, as may the fact that only certain groups of insects occur in specific regions of large countries like Brazil.

‣ Clonagem, expressão e avaliação do potencial biotecnológico de um inibidor de tripsina de Inga laurina em relação aos insetos pragas Diatraea saccharalis e Heliothis virescens; Cloning, expression and evaluation of biotechnological potential of Inga laurina trypsin inhibitor on insect pests Diatraea saccharalis and Heliothis virescens

Vanessa da Silveira Ramos
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 26/02/2013 Português
Relevância na Pesquisa
36.646592%
Os inibidores de tripsina têm sido utilizados com sucesso para aumentar a resistência das plantas contra os insetos. No presente trabalho avaliamos a eficiência de um inibidor de tripsina de Inga laurina (ILTI) sobre o desenvolvimento de larvas de Diatraea saccharalis e Heliothis virescens, duas importantes pragas da cana-de-açúcar e tabaco, respectivamente. Para estes fins foram utilizadas diversas estratégias (i) purificação da proteína ILTI nativa a partir de sementes de I. laurina e sua utilização para suplementação de dieta artificial fornecida como alimento às larvas dos insetos em estudo. Isto com o intuito de avaliar os efeitos do inibidor no desenvolvimento destes indivíduos; (ii) obtenção da sequência de DNA do gene ilti, clonagem, expressão e purificação da proteína recombinante assim como avaliação da sua atividade inibitória; (iii) obtenção de plantas transgênicas de cana-de-açúcar e tabaco com o gene ilti obtido a partir do DNA genômico de I. laurina ou do gene ilti-s sintetizado quimicamente usando o uso de códons da cana-de-açúcar. A adição de 0,1% (p/p) de ILTI na dieta de D. saccharalis não alterou a sobrevivência larval, mas resultou em uma redução de 56% no peso das larvas. As larvas de H. virescens que foram alimentadas em uma dieta contendo 0...

‣ Susceptibility of Aedes aegypti (L) to the insect growth regulators diflubenzuron and methoprene in Uberlândia, State of Minas Gerais

Silva,Juliana Junqueira da; Mendes,Júlio
Fonte: Sociedade Brasileira de Medicina Tropical - SBMT Publicador: Sociedade Brasileira de Medicina Tropical - SBMT
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2007 Português
Relevância na Pesquisa
36.593477%
Aedes aegypti (L) (Diptera: Culicidae) was reared in several concentrations of diflubenzuron and methoprene under laboratory conditions in Uberlândia, State of Minas Gerais, southeastern Brazil. Characteristics such as LC50 and LC95, the susceptibility of immature stages of different ages to these insect growth regulators and their residual effects were studied. The LC50 and LC95 of diflubenzuron and methoprene were 5.19 and 12.24 ppb; 19.95 and 72.08 ppb, respectively. While diflubenzuron caused great mortality in all larval instars, methoprene was more effective when the mosquito was exposed from the start of the fourth larval instar onwards. Commercial concentrations of these two insect growth regulators close to LC95 presented greater residual activity than did their respective technical formulations. The parameters were compared with those obtained elsewhere. The characteristics investigated here indicate that these insect growth regulators are effective alternatives for controlling the dengue vector in the Uberlândia region.

‣ Transmission blocking vaccines to control insect-borne diseases: a review

Coutinho-Abreu,Iliano V; Ramalho-Ortigao,Marcelo
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2010 Português
Relevância na Pesquisa
36.686753%
Insect-borne diseases are responsible for severe mortality and morbidity worldwide. As control of insect vector populations relies primarily on the use of insecticides, the emergence of insecticide resistance as well to unintended consequences of insecticide use pose significant challenges to their continued application. Novel approaches to reduce pathogen transmission by disease vectors are been attempted, including transmission-blocking vaccines (TBVs) thought to be a feasible strategy to reduce pathogen burden in endemic areas. TBVs aim at preventing the transmission of pathogens from infected to uninfected vertebrate host by targeting molecule(s) expressed on the surface of pathogens during their developmental phase within the insect vector or by targeting molecules expressed by the vectors. For pathogen-based molecules, the majority of the TBV candidates selected as well as most of the data available regarding the effectiveness of this approach come from studies using malaria parasites. However, TBV candidates also have been identified from midgut tissues of mosquitoes and sand flies. In spite of the successes achieved in the potential application of TBVs against insect-borne diseases, many significant barriers remain. In this review...

‣ Insect herbivores associated with an evergreen tree Goniorrhachis marginata Taub. (Leguminosae: Caesalpinioideae) in a tropical dry forest

Silva,JO; Neves,FS
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2014 Português
Relevância na Pesquisa
36.593477%
Goniorrhachis marginata Taub. (Leguminosae: Caesalpinioideae) is a tree species found in Brazilian tropical dry forests that retain their leaves during the dry season. That being, we addressed the following question: i) How do insect diversity (sap-sucking and chewing), leaf herbivory and defensive traits (tannin and leaf sclerophylly) vary on the evergreen tree species G. marginata between seasons? The abundance of sap-sucking insects was higher in the dry season than in the rainy season. However, we did not verify any difference in the species richness and abundance of chewing insects between seasons. Leaf herbivory was higher in the rainy season, whereas leaf sclerophylly was higher in the dry season. However, herbivory was not related to sclerophylly. Insect herbivores likely decrease their folivory activity during the dry season due to life history patterns or changes in behaviour, possibly entering diapause or inactivity during this period. Therefore, G. marginata acts as a likely keystone species, serving as a moist refuge for the insect fauna during the dry season in tropical dry forest, and the presence of this evergreen species is crucial to conservation strategies of this threatened ecosystem.

‣ Insect galls of the xeric vegetation of Ilha do Cabo Frio (Arraial do Cabo, RJ, Brazil)

Maia,Valeria Cid; Souza,Marcelo da Costa
Fonte: Instituto Virtual da Biodiversidade | BIOTA - FAPESP Publicador: Instituto Virtual da Biodiversidade | BIOTA - FAPESP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2013 Português
Relevância na Pesquisa
36.593477%
The xeric vegetation of Ilha do Cabo Frio (Arraial do Cabo, RJ) was investigated for insect galls, in May, June and August of 2012, totalizing 24 hours of field work. Forty-five morphotypes of insect galls were found on 29 species of host plant (25 genera and 18 families). Asteraceae and Myrtaceae were the most galled plant families. Leaves were the most galled plant organ, with ca. 62% of the total, followed by stems (ca. 22%). Globoid and fusiform galls were the most frequent with about 29% and 24%, respectively. The majority was glabrous (ca. 91%), and one-chambered (ca. 84%). Gallers of 30 morphotypes were determined. They belong to Diptera (Cecidomyiidae), and Lepidoptera. The former was the most frequent. Larvae of Muscomorpha (Diptera) (probably inquilines) were found in a single gall morphotype; parasitoids (Hymenoptera) in seven (ca. 15% of the total), and predators (pseudoscorpion) in a single one. As there is no previous data of insect galls of Ilha do Cabo Frio, all records presented here are new. The geographic distribution of nine species of gall midges (Diptera, Cecidomyiidae) is widened. For the first time, eleven plant species are recorded as host of galling insects, and 24 gall morphotypes are described.

‣ Insect galls of Sao Tome das Letras (MG, Brazil)

Maia,Valeria Cid
Fonte: Instituto Virtual da Biodiversidade | BIOTA - FAPESP Publicador: Instituto Virtual da Biodiversidade | BIOTA - FAPESP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2013 Português
Relevância na Pesquisa
36.593477%
Six localities of São Tomé das Letras (MG, Brazil) were investigated from September, 2011 to June, 2012. The local vegetation was examined in search of insect galls. A total of 152 morphotypes of insect galls were found on 94 plant species (74 genera and 37 families). Fabaceae, Melastomataceae, Myrtaceae, and Asteraceae were the plant families with the greatest richness of galls, with 20, 18, 17, and 12 gall morphotypes, respectively. The super host genera were Copaifera L. (Fabaceae), Myrcia DC. ex. Guill. (Myrtaceae), and Miconia Ruiz & Pav. (Melastomataceae), with 10, 10 and 09 gall morphotypes, respectively. The super host species was Copaifera cf.langsdorfii Desf. (Fabaceae), with 10 gall morphotypes. Galls were found on leaves, stems, buds, and aerial roots. Leaves were the most galled plant organ, followed by stems, and buds. The inducers belong to Diptera, Lepidoptera, Hemiptera, Thysanoptera, Coleoptera, and Hymenoptera, being Cecidomyiidae (Diptera) the most frequent and diversified gallers. The associated fauna included parasitoids (Hymenoptera), inquilines (Lepidoptera and Thysanoptera), successors (Formicidae, Hymenoptera), and predators (pseudoscorpion), obtained from 18, 02, 02, and 01 gall morphotype, respectively. Ten galling species are recorded for the first time in São Tomé das Letras (MG). The present study indicates São Tomé das Letras (MG) as an area of great richness of insect galls.

‣ Insect galls of Itamonte (Minas Gerais, Brazil): characterization and occurrence

Maia,Valéria Cid
Fonte: Instituto Virtual da Biodiversidade | BIOTA - FAPESP Publicador: Instituto Virtual da Biodiversidade | BIOTA - FAPESP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2014 Português
Relevância na Pesquisa
36.686753%
Three sites of Itamonte (Minas Gerais) were investigated for insect galls from September, 2011 to July, 2012, seasonally. One-hundred and one morphotypes of insect galls were recorded on 63 species of host plant (45 genera and 23 families). Melastomataceae was the most galled plant family, followed by Asteraceae and Myrtaceae. Galls were recorded on leaves, stems, buds, and aerial roots. Leaves were the most galled plant organ. The gall morphotypes were characterized according to their shape, color, pubescence, and number of internal chambers. Globose and fusiform galls were the most frequent. The majority was glabrous and one-chambered. The gallers comprised three insect orders: Diptera (Cecidomyiidae and Tephritidae), Hemiptera, and Lepidoptera. Cecidomyiidae were the most frequent galling taxa. Parasitoids (Hymenoptera) were obtained from six morphotypes (ca. 6% of the total). The results are compared to those of other Brazilian insect gall inventories. As there is no previous gall inventory in Itamonte, all records presented here are new.

‣ Quantification of Insect-Induced Foliage Damage Using a High-Capacity Laboratory Bioassay

Herman, Rod A.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
Português
Relevância na Pesquisa
36.593477%
A high-capacity assay designed to evaluate insect-induced foliage damage was developed based on the optical density of dimethyl sulfoxide extracts of leaf tissue. The assay reliably indexed foliage damage induced by both chewing insects, Spodoptera eridania (Cramer), and piercing-sucking insects, Empoasca abrupta DeLong. Results from this assay correlated well with simulated damage levels, insect infestation levels, leaf dry-weight measurements, and visual leaf damage estimates. Results from dose-response tests with malathion using larvae of S. eridania indicate that this assay is useful for evaluating chemicals for their ability to protect plants from insect damage. The assay could be adapted to evaluate other types of plant damage such as those induced by herbicides, air pollutants, or disease.

‣ Effect of Temperature and Duration of Trapping on Four Stored Grain Insect Species

Fargo, W. S.; Epperly, D.; Cuperus, G. W.; Clary, B. C.; Noyes, R.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
Português
Relevância na Pesquisa
36.686753%
Capturing stored grain insects with drop traps in wheat was affected by insect species, grain temperature, and trapping duration. These results were obtained using four insect species (Tribolium castaneum (Herbst), Sitophilus oryzae (L.), Rhyzopertha dominica (F.), and Cryptolestes ferrugineus (Stephens), three grain temperatures (10.0, 21.1, and 32.2°C), and four trapping intervals (I, 2, 4, and 7 d). Higher grain temperatures resulted in significantly more insects trapped when all species were combined. This significance is largely due to the highly significant numbers of C. ferrugineus captured at high temperatures. The other species followed the same pattern. At each temperature, C. ferrugineus was caught in the greatest numbers and R. dominica in the least. S. oryzae and T. castaneum were captured in intermediate numbers. Across species, longer trapping durations resulted in significantly more insects being captured. Across durations, C. ferrugineus was caught the most, R. dominica the least, with the other two species intermediate. Within species, only C. ferrugineus. showed significant differences in the number trapped among the sampling periods. The trend...

‣ The coagulation of insect hemolymph

Theopold, Ulrich J.; Li, Dongmei; Fabbri, Marco; Scherfer, Christoph; Schmidt, Otto
Fonte: Birkhauser Verlag Ag Publicador: Birkhauser Verlag Ag
Tipo: Artigo de Revista Científica
Publicado em //2002 Português
Relevância na Pesquisa
36.593477%
In contrast to both vertebrates and non-insect arthropods, little is known about the coagulation of hemolymph (hemostasis) in insects. We discuss the integration of the hemostatic response with other branches of the insect immune system. We also describe the present stage in the characterization of both soluble and cellular factors that contribute to hemostasis in insects. The factors of the well-characterized clotting cascades of vertebrates, CMLS, Cell. Mol. Life Sci. 59 (2002) 363–372 1420-682X/02/020363-10 $ 1.50 + 0.20/0 © Birkhäuser Verlag, Basel, 2002 CMLS Cellular and Molecular Life Sciences primitive chelicerates and crustaceans are used to assess the implications of sequencing the whole Drosophila genome for searching candidate genes involved in hemostasis. Some striking similarities between blood clotting in vertebrates and the reaction of insect cells involved in hemolymph coagulation have implications for a phylogenetic comparison of hemostasis between divergent animal classes.; U. Theopold, D. Li, M. Fabbri, C. Scherfer and O. Schmidt; The original publication can be found at www.springerlink.com

‣ Insect molecular biology: an Australian perspective

Glatz, R.; Kent, J.
Fonte: Blackwell Science Asia Publicador: Blackwell Science Asia
Tipo: Artigo de Revista Científica
Publicado em //2011 Português
Relevância na Pesquisa
36.74345%
One of the biggest advances in biological research has undoubtedly been the development of our capacity to investigate individual phenotypes, species biology and multi-species interactions at the molecular level. This has provided the ability to understand the detailed mechanisms that regulate biological processes and, in many cases, to manipulate them or use them to our advantage. In this Overview we define ‘insect molecular biology’ as the study of gene/protein expression and molecular function and contrast it with ‘traditional entomology’ and ‘comparative molecular entomology’. Obtaining the genomes of various insect species has provided significant advances in our ability to quickly isolate important genes. Study of the proteins they produce is important as they are functionally extremely diverse and are the basis for biological differences in extant species. Australian researchers have contributed significantly to our knowledge of insect molecular biology. Functional insect molecular biology studies undertaken in Australia are summarised, concentrating on the last 15 years, during which time insect molecular research has accelerated, largely due to obtaining key insect genomes and corresponding advances in molecular technologies. Currently...

‣ Effects of insect cadavers infected by Heterorhabditis bacteriophora and Steinernema diaprepesi on Meloidogyne incognita parasitism in pepper and summer squash plants

del Valle, Eleodoro Eduardo; Lax, Paola; Rondan Dueñas, Juan; Doucet, Marcelo Edmundo
Fonte: Pontificia Universidad Catolica Chile Publicador: Pontificia Universidad Catolica Chile
Tipo: info:eu-repo/semantics/article; info:ar-repo/semantics/artículo; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Português
Relevância na Pesquisa
36.686753%
E. E. Del Valle, P. Lax, J. Rondán Dueñas, and M. E. Doucet. 2013. Effects of insect cadavers  infected  by  Heterorhabditis  bacteriophora  and  Steinernema  diaprepesi  on Meloidogyne incognita parasitism in pepper and summer squash plants.  The effects of insect cadavers infected with three isolates of Heterorhabditis bacteriophora and one isolate of Steinernema diaprepesi on a population of Meloidogyne incognita  in  pepper  (Capsicum  annuum)  and  summer  squash  (Cucurbita  maxima)  were evaluated in greenhouse experiments carried out in Santa Fe (Argentina). Insect cadavers were obtained for the experiments from last instar larvae of Galleria mellonella and Tenebrio molitor  that had  been  infected  with  entomopathogenic nematodes.  Two  six-day-old  insect cadavers per pot were placed below the soil surface, and the soil was inoculated with 100 second-stage juveniles of M. incognita. Sixty days after inoculation, the following parameters were recorded for each plant: number of leaves; dry weight of aerial parts; numbers of galls, egg masses and eggs; and numbers of galls, egg masses and eggs g -1  of root fresh matter. In pepper, the only variable affected by the infected cadavers with respect to control was the number of eggs in the treatment involving T. molitor cadavers infected with the H. bacteriophora isolate Rama  Caída.  In  summer  squash...

‣ Caracterización espacial y temporal de la estructura genética del primer insecto blanco del maíz transgénico Bt en Argentina, el barrenador Diatraea saccharalis (Fabricius); Spatial and temporal characterization of the genetic structure of the first target insect of Bt corn in Argentina, the sugarcane borer Diatraea saccharalis (Fabricius)

Parody, Betiana Paula
Fonte: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires Publicador: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires
Tipo: info:eu-repo/semantics/doctoralThesis; tesis doctoral; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2011 Português
Relevância na Pesquisa
36.764204%
Durante la última década, distintos eventos de maíz transgénico resistente a insectos (maíz Bt) han sido cultivados extensamente en la Argentina. La principal plaga blanco de los primeros eventos de maíz Bt en Argentina ha sido el barrenador del tallo, Diatraea saccharalis (F.) (Crambidae). La eficacia de estos eventos puede verse limitada por la capacidad de los insectos blanco de desarrollar resistencia. La evolución de la resistencia de los insectos a los cultivos Bt depende de muchos factores biológicos, ambientales y genéticos, como la estructura genética espacial de las poblaciones de los insectos blanco, y el flujo génico entre las poblaciones. En Argentina, la CONABIA propicia un plan de manejo de la resistencia de insectos al maíz Bt, el cual es cumplimentado por las compañías semilleras por medio de programas de monitoreo. Hasta el momento, en Argentina, no se ha documentado la aparición de resistencia en poblaciones de campo de D. saccharalis. Aún no se ha investigado la genética las poblaciones del barrenador a fin de entender la estructura genética espacial de esta especie. La estructura genética del insecto blanco del cultivo Bt puede ser una información útil a la hora de determinar las unidades de monitoreo. En este contexto...

‣ Ultraviolet-Blocking Materials as a Physical Barrier to Control Insect Pests and Plant Pathogens in Protected Crops

Díaz, Beatriz; Fereres, Alberto
Fonte: Global Science Books Publicador: Global Science Books
Tipo: Artículo Formato: 623412 bytes; application/pdf
Português
Relevância na Pesquisa
36.646592%
11 pages, 1 figure, and tables; New types of ultraviolet (UV)-blocking materials, such as polyethylene films and nets, have been developed in recent years as a very promising tool to control insect vectors of plant disease threatening greenhouse crops. UV-blocking materials have properties to filter the UV radiation (280-400 nm) interfering with the vision of insects and in consequence, their behaviour related with movement, host location ability and their population parameters. The exclusion of part of the UV radiation within the greenhouse environment has a dramatically incidence on insect orientation, movement and on the spread of insect-transmitted viral diseases. In the same way, the impact of UV-absorbing materials on population dynamics of natural enemies, pollinators and crop yield needs further investigation. The level of protection of the different UV-blocking materials may vary among different designs of greenhouses and the geographic location that determines different internal climatic conditions and the amount of UV and visible light absorbed and transmitted within the covered structures. In this review, we will discuss the current knowledge about the impact of UV-absorbing films on insect pests, plant pathogens and beneficial organisms...

‣ Interactions of insect pheromones and plant semiochemicals

Reddy, Gadi V. P.; Guerrero, Ángel
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 22195 bytes; application/pdf
Português
Relevância na Pesquisa
36.646592%
9 pages, 2 figures, 2 tables.-- PMID: 15130551 [PubMed].-- Printed version published May 2004.; Plant semiochemicals are known to produce a wide range of behavioral responses in insects. Some insects sequester or acquire host plant compounds and use them as sex pheromones or sex pheromone precursors. Other insects produce or release sex pheromones in response to specific host plant cues, and chemicals from host plants often synergistically enhance the response of an insect to sex pheromones. Plant volatiles can also have inhibitory or repellent effects that interrupt insect responses to pheromones and attract predators and parasitoids to the attacking species after herbivory injury. Here, we review different interactions between plant semiochemicals and insect pheromones, paying attention to those that can result in the development of more efficient and reliable programs for pest control.; We gratefully acknowledge CICYT for financial support (AGL2000–1695-C02–01).; Peer reviewed

‣ Indirect Training Algorithms for Spiking Neural Networks Controlled Virtual Insect Navigation

Zhang, Xu
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Tese de Doutorado
Publicado em //2015 Português
Relevância na Pesquisa
36.646592%

Even though Articial Neural Networks have been shown capable of solving many problems such as pattern recognition, classication, function approximation, clinics, robotics, they suers intrinsic limitations, mainly for processing large amounts of data or for fast adaptation to a changing environment. Several characteristics, such as iterative learning algorithms or articially designed neuron model and network architecture, are strongly restrictive compared with biological processing in natural neural networks. Spiking neural networks as the newest generation of neural models can overcome the weaknesses of ANNs. Because of the biologically realistic properties, the electrophysiological recordings of neural circuits can be compared to the outputs of the corresponding spiking neural network simulated on the computer, determining the plausibility of the starting hypothesis. Comparing with ANN, it is known that any function that can be computed by a sigmoidal neural network can also be computed by a small network of spiking neurons. In addition, for processing a large amount of data, SNNs can transmit and receive a large amount of data through the timing of the spikes and remarkably decrease the interactions load between neurons. This makes possible for very ecient parallel implementations.

Many training algorithms have been proposed for SNN training mainly based on the direct update of the synaptic plasticities or weights. However...

‣ Contrasting effects of sampling scale on insect herbivores distribution in response to canopy structure

Neves,Frederico S.; Sperber,Carlos F.; Campos,Ricardo I.; Soares,Janaína P.; Ribeiro,Sérvio P.
Fonte: Revista de Biología Tropical Publicador: Revista de Biología Tropical
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2013 Português
Relevância na Pesquisa
36.646592%
Species diversity of insect herbivores associated to canopy may vary local and geographically responding to distinct factors at different spatial scales. The aim of this study was to investigate how forest canopy structure affects insect herbivore species richness and abundance depending on feeding guilds´ specificities. We tested the hypothesis that habitat structure affects insect herbivore species richness and abundance differently to sap-sucking and chewing herbivore guilds. Two spatial scales were evaluated: inside tree crowns (fine spatial scale) and canopy regions (coarse spatial scale). In three sampling sites we measured 120 tree crowns, grouped in five points with four contiguous tree crowns. Insects were sampled by beating method from each crown and data were summed up for analyzing each canopy region. In crowns (fine spatial scale) we measured habitat structure: trunk circumference, tree height, canopy depth, number of ramifications and maximum ramification level. In each point, defined as a canopy region (coarse spatial scale), we measured habitat structure using a vertical cylindrical transect: tree species richness, leaf area, sum of strata heights and maximum canopy height. A principal component analysis based on the measured variables for each spatial scale was run to estimate habitat structure parameters. To test the effects of habitat structure upon herbivores...