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Ecologia de Methylobacterium spp. na planta hospedeira; Methylobacterium spp. ecology in the host plant

Dourado, Manuella Nóbrega
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 14/06/2010 PT
Relevância na Pesquisa
56.25%
O gênero Methylobacterium é composto por bactérias de coloração rósea, metilotróficas facultativas (PPFM - pink-pigmented facultative methylotrophic), que podem fixar nitrogênio, nodular a planta hospedeira, produzir o fitohormônio citocinina e as enzimas pectinase e celulase, podendo dessa forma promover o crescimento vegetal devido à disponibilidade de nitrogênio e à indução de resistência sistêmica. Methylobacterium spp. têm sido descritas como endófitos ou epífitas em diferentes plantas hospedeiras, onde a sua colonização e distribuição no hospedeiro podem ser influenciadas pelo genótipo da planta ou por interações com outros microrganismos associados ao hospedeiro. Neste contexto, poucos trabalhos têm sido desenvolvidos visando um melhor entendimento da interação Methylobacterium-planta e da diversidade deste gênero bacteriano que tem sido isolado de diferentes plantas hospedeiras, exercendo diferentes funções ainda pouco conhecidas. Portanto, este trabalho tem como objetivo estudar a diversidade genética de Methylobacterium spp., por meio do seqüenciamento parcial dos genes 16S rRNA e mxaF; analisar os genes de responsáveis pela interação da Methylobacterium com a planta hospedeira e analisar os genes envolvidos na interação Methylobacterium (endófito)- Xylella fastidiosa (patógeno). Os resultados mostraram que existe uma resposta adaptativa de Methylobacterium spp. específica para cada planta hospedeira. Da mesma forma...

Preferência alimentar, efeito da planta hospedeira e da densidade larval na sobrevivência e desenvolvimento de Dione juno juno (Cramer) (Lepidoptera, Nymphalidae); Feeding preference, host-plant and larval density effects on survivorship and growth rates of Dione juno juno (Cramer) (Lepidoptera, Nymphalidae)

Bianchi, Vidica; Moreira, Gilson Rudinei Pires
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
POR
Relevância na Pesquisa
66.01%
Dez espécies de passifloraceas ocorrentes no Rio Grande do Sul foram avaliadas em relação à preferência alimentar e performance larval de Dione juno juno (Cramer, 1779) (Lepidoptera, Nymphalidae): Passifora alata Dryander, 1781; P. amethystina Mikan, 1820; P. caerulea Linnaeus, 1753; P. capsularis Linnaeus, 1753; P. edulis Sims, 1818; P. elegans Masters, 1872; P. misera Humbold, Bonpland et Kunth, 1817; P. suberosa Linnaeus, 1753; P. tenuifila Killip, 1927 e P. warmingii Masters, 1872. O efeito da densidade larval na performance foi também testado em P. edulis: grupos de uma, duas, quatro, oito, dezesseis, trinta e duas, e sessenta e quatro larvas. A preferência das larvas foi avaliada com base em teste utilizando-se discos foliares, com e sem chance de escolha. As larvas obtiveram maior sobrevivência em P. misera, P. tenuifila e P. edulis. Nenhuma sobreviveu em P. alata, P. capsularis, P. amesthystina, P. suberosa e P. warmingii. As larvas escolheram P. edulis nos testes com chance de escolha. Ingeriram quantidades semelhantes de P. tenuifila, P. misera e P. caerulea nos testes sem chance de escolha. A taxa de crescimento larval e o tamanho dos adultos foi maior quando criadas em P. misera, quando comparado com P. edulis. A sobrevivência foi significativamente reduzida nos grupos com uma...

Geographic range, habitats, and host plants of bromeliad-living jumping spiders (Salticidae)

Romero, Gustavo Q.
Fonte: Blackwell Publishing Publicador: Blackwell Publishing
Tipo: Artigo de Revista Científica Formato: 522-530
ENG
Relevância na Pesquisa
56.08%
Although spiders are a very diverse group on vegetation, their associations with plants are poorly known. Some salticid species specifically use Bromeliaceae as host plants in some regions of South America. In this study, I report the geographic range of these spider-bromeliad associations, and whether the spiders inhabit particular bromeliad species and vegetation types, as well as open areas or interior of forests. Nine salticid species were found to be associated with up to 23 bromeliad species in cerrados (savanna-like vegetation), semideciduous and seasonal forests, coastal sand dune vegetation, restingas, inselbergs, highland forests, chacos, and rain forests at 47 localities in Brazil, Paraguay, Bolivia, and Argentina. Some species were typically specialists, inhabiting almost exclusively one bromeliad species over a large geographic range (e.g., Psecas chapoda on Bromelia balansae), whereas others were generalists, occurring on up to 7-8 bromeliad species (e.g., Psecas sp., Eustiromastix nativo, and Coryphasia sp. 1). The regional availability of bromeliad species among habitats may explain this pattern of host plant use. More jumping spiders were found on bromeliads in open areas than on bromeliads in the interior of forests. These results show that several jumping spider species may be strictly associated with the Bromeliaceae in the Neotropics. This is one of the few studies to show host-specific associations for spiders on a particular plant type over a wide geographic range.

Colonization pattern of Cecropia by Azteca ants: Influence of plant ontogeny, environment and host plant choice by queens

Nishi, Aline H.; Romero, Gustavo Q.
Fonte: California State University Publicador: California State University
Tipo: Artigo de Revista Científica Formato: 367-376
ENG
Relevância na Pesquisa
66.13%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 04/13658-5; Processo FAPESP: 05/51421-0; Several plant species of the large Neotropical genus Cecropia acts as a host plant for ants, especially those of the genus Azteca. Although literature has reported that the Azteca queens found colonies by perforating the prostoma to establish their nests inside the Cecropia trunks (domatia), little is known about which host plant parameters (e.g., ontogenetic development) are evaluated by the queens to choose their hosts, or even whether this choice influences colony success. Because larger plants provide more space and food, it is expected that queens of the plant ant Azteca sp. can more frequently colonize the larger plants of C pachystachya, and that active colonies, i.e., those with active workers, occur more frequently in these plants. In our study, founding queens occurred more frequently in larger plants. However, linear regressions showed a strong positive relationship between trunk diameter and number of perforated prostomes on young plants yet without active colonies of Azteca sp., indicating that queens colonize plants which arc still very young. In these plants several dead and moribund queens were found inside the basal and apical internodes...

Relationships between host plant architecture and gall abundance and survival

Lara,Daniela P.; Oliveira,Lázaro A.; Azevedo,Islaine F. P.; Xavier,Márcia F.; Silveira,Fernando A. O.; Carneiro,Marco Antonio Alves; Fernandes,G. Wilson
Fonte: Sociedade Brasileira De Entomologia Publicador: Sociedade Brasileira De Entomologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2008 EN
Relevância na Pesquisa
56.17%
The plant architecture hypothesis predicts that variation in host plant architecture influences insect herbivore community structure, dynamics and performance. In this study we evaluated the effects of Macairea radula (Melastomataceae) architecture on the abundance of galls induced by a moth (Lepidoptera: Gelechiidae). Plant architecture and gall abundance were directly recorded on 58 arbitrarily chosen M. radula host plants in the rainy season of 2006 in an area of Cerrado vegetation, southeastern Brazil. Plant height, dry biomass, number of branches, number of shoots and leaf abundance were used as predicting variables of gall abundance and larval survival. Gall abundance correlated positively with host plant biomass and branch number. Otherwise, no correlation (p > 0.05) was found between gall abundance with shoot number or with the number of leaves/plant. From a total of 124 galls analyzed, 67.7% survived, 14.5% were attacked by parasitoids, while 17.7% died due to unknown causes. Larvae that survived or were parasitized were not influenced by architectural complexity of the host plant. Our results partially corroborate the plant architecture hypothesis, but since parasitism was not related to plant architecture it is argued that bottom-up effects may be more important than top-down effects in controlling the population dynamics of the galling lepidopteran. Because galling insects often decrease plant fitness...

Conspecific mimics and low host plant availability reduce egg laying by Heliconius erato phyllis (Fabricius) (Lepidoptera, Nymphalidae)

Mugrabi-Oliveira,Elna; Moreira,Gilson R.P
Fonte: Sociedade Brasileira de Zoologia Publicador: Sociedade Brasileira de Zoologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/1996 EN
Relevância na Pesquisa
56.18%
Oviposition response of Heliconius erato phyllis (Fabricius, 1775) (Lepidoptera, Nymphalidae) to variation in host plant availability, Passiflora suberosa Linnaeus (Passifloraceae), and to presence of conspecific eggs and larvae was determined through choice experiments performed under insectary conditions. Freeze dried, painted eggs and larvae were used as mimics for testing presence of conspecific effects. Females laid more eggs on intact P. suberosa shoots without conspecifics than on those with H. erato phyllis egg and first instar mimics in both simultaneous and sequential choice trials. Oviposition response to variation in host plant availability was determined through no-choice trials, under host plant densities varying from 0.3 to 8.3 plants per female. Number of eggs laid per plant decreased exponentially with an increase in plant availability. On the contrary, daily oviposition rates (eggs /female/day) increased with an increase in plant number, and levelled off when the number of plants available for oviposition was greater than potential fecundity of females. Thus, it is inferred from the results that females assess egg and larval load and prefer to lay eggs on shoots free from conspecifics. It is also inferred that they are able to recognize plant abundance and are unwilling to lay more than one egg per shoot even when host availability is scarce...

Plant Vigor Hypothesis refuted: preference-performance linkage of a gall-inducing weevil on small-sized host plant resources

Santos,JC.; Tavares,CB.; Almeida-Cortez,JS.
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2011 EN
Relevância na Pesquisa
66.06%
The Plant Vigor Hypothesis (PVH) predicts an oviposition preference of females and higher offspring performance for insect herbivores on longer and fast-growing plant modules. We tested the PVH predictions by investigating the effects of leaf size of Miconia prasina (Sw.) DC. (Melastomataceae) on the oviposition preference and on the offspring survival of the gall-inducing weevil Prospoliata bicolorata (Coleoptera: Curculionidae). Additionally, we analysed the effects of top-down mortality force on this system. Approximately 83% of the developed galls resulted in adults of P. bicolorata, whereas 17% of the galls successfully induced were killed by natural enemies (top-down effect). Leaves of intermediate size were more abundant while smaller and longer leaves were rare. Nevertheless, the percentage of P. bicolorata galls was higher on the smallest leaves of M. prasina, refuting the preference prediction of the PVH. Our results also refuted the performance prediction: the ratio of survival per leaf was negatively related to the leaf length. Thus, we found a link between female preference and larval performance of P. bicolorata on small-sized leaves of M. prasina. The next goal is to understand the mechanisms involved in the selection of gall-inducing weevil on short leaves of its host plant.

Successive Use of Non-Host Plant Proteinase Inhibitors Required for Effective Inhibition of Helicoverpa armigera Gut Proteinases and Larval Growth1

Harsulkar, Abhay M.; Giri, Ashok P.; Patankar, Aparna G.; Gupta, Vidya S.; Sainani, Mohini N.; Ranjekar, Prabhakar K.; Deshpande, Vasanti V.
Fonte: American Society of Plant Physiologists Publicador: American Society of Plant Physiologists
Tipo: Artigo de Revista Científica
Publicado em /10/1999 EN
Relevância na Pesquisa
56.1%
We report on the efficacy of proteinase inhibitors (PIs) from three host plants (chickpea [Cicer arietinum], pigeonpea [Cajanus cajan], and cotton [Gossypium arboreum]) and three non-host (groundnut [Arachis hypogea], winged bean [Psophocarpus tetragonolobus], and potato [Solanum tuberosum]) in retarding the growth of Helicoverpa armigera larvae, a devastating pest of important crop plants. Enzyme assays and electrophoretic analysis of interaction of H. armigera gut proteinases (HGPs) with PIs revealed that non-host PIs inhibited HGP activity efficiently whereas host PIs were ineffective. In the electrophoretic assay, trypsin inhibitor activity bands were detected in all of the host and non-host plants, but HGP inhibitor activity bands were present only in non-host plants (except cotton in the host plant group). H. armigera larvae reared on a diet containing non-host PIs showed growth retardation, a reduction in total and trypsin-like proteinase activity, and the production of inhibitor-insensitive proteinases. Electrophoretic analysis of PI-induced HGP showed differential regulation of proteinase isoforms. Interestingly, HGP activity induced in response to dietary potato PI-II was inhibited by winged bean PIs. The optimized combination of potato PI-II and winged bean PIs identified in the present study and their proposed successive use has potential in developing H. armigera-resistant transgenic plants.

Role of Pseudomonas putida Indoleacetic Acid in Development of the Host Plant Root System

Patten, Cheryl L.; Glick, Bernard R.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /08/2002 EN
Relevância na Pesquisa
56.07%
Many plant-associated bacteria synthesize the phytohormone indoleacetic acid (IAA). While IAA produced by phytopathogenic bacteria, mainly by the indoleacetamide pathway, has been implicated in the induction of plant tumors, it is not clear whether IAA synthesized by beneficial bacteria, usually via the indolepyruvic acid pathway, is involved in plant growth promotion. To determine whether bacterial IAA enhances root development in host plants, the ipdc gene that encodes indolepyruvate decarboxylase, a key enzyme in the indolepyruvic acid pathway, was isolated from the plant growth-promoting bacterium Pseudomonas putida GR12-2 and an IAA-deficient mutant constructed by insertional mutagenesis. The canola seedling primary roots from seeds treated with wild-type P. putida GR12-2 were on average 35 to 50% longer than the roots from seeds treated with the IAA-deficient mutant and the roots from uninoculated seeds. In addition, exposing mung bean cuttings to high levels of IAA by soaking them in a suspension of the wild-type strain stimulated the formation of many, very small, adventitious roots. Formation of fewer roots was stimulated by treatment with the IAA-deficient mutant. These results suggest that bacterial IAA plays a major role in the development of the host plant root system.

Parasitism by Cuscuta pentagona Attenuates Host Plant Defenses against Insect Herbivores1

Runyon, Justin B.; Mescher, Mark C.; De Moraes, Consuelo M.
Fonte: American Society of Plant Biologists Publicador: American Society of Plant Biologists
Tipo: Artigo de Revista Científica
Publicado em /03/2008 EN
Relevância na Pesquisa
66.02%
Considerable research has examined plant responses to concurrent attack by herbivores and pathogens, but the effects of attack by parasitic plants, another important class of plant-feeding organisms, on plant defenses against other enemies has not been explored. We investigated how attack by the parasitic plant Cuscuta pentagona impacted tomato (Solanum lycopersicum) defenses against the chewing insect beet armyworm (Spodoptera exigua; BAW). In response to insect feeding, C. pentagona-infested (parasitized) tomato plants produced only one-third of the antiherbivore phytohormone jasmonic acid (JA) produced by unparasitized plants. Similarly, parasitized tomato, in contrast to unparasitized plants, failed to emit herbivore-induced volatiles after 3 d of BAW feeding. Although parasitism impaired antiherbivore defenses, BAW growth was slower on parasitized tomato leaves. Vines of C. pentagona did not translocate JA from BAW-infested plants: amounts of JA in parasite vines grown on caterpillar-fed and control plants were similar. Parasitized plants generally contained more salicylic acid (SA), which can inhibit JA in some systems. Parasitized mutant (NahG) tomato plants deficient in SA produced more JA in response to insect feeding than parasitized wild-type plants...

Electroantennographic Bioassay as a Screening Tool for Host Plant Volatiles

Beck, John J.; Light, Douglas M.; Gee, Wai S.
Fonte: MyJove Corporation Publicador: MyJove Corporation
Tipo: Artigo de Revista Científica
Publicado em 06/05/2012 EN
Relevância na Pesquisa
56.15%
Plant volatiles play an important role in plant-insect interactions. Herbivorous insects use plant volatiles, known as kairomones, to locate their host plant.1,2 When a host plant is an important agronomic commodity feeding damage by insect pests can inflict serious economic losses to growers. Accordingly, kairomones can be used as attractants to lure or confuse these insects and, thus, offer an environmentally friendly alternative to pesticides for insect control.3 Unfortunately, plants can emit a vast number volatiles with varying compositions and ratios of emissions dependent upon the phenology of the commodity or the time of day. This makes identification of biologically active components or blends of volatile components an arduous process. To help identify the bioactive components of host plant volatile emissions we employ the laboratory-based screening bioassay electroantennography (EAG). EAG is an effective tool to evaluate and record electrophysiologically the olfactory responses of an insect via their antennal receptors. The EAG screening process can help reduce the number of volatiles tested to identify promising bioactive components. However, EAG bioassays only provide information about activation of receptors. It does not provide information about the type of insect behavior the compound elicits; which could be as an attractant...

Host Plant Specialization Driven by Sexual Selection

Quental, Tiago; Pierce, Naomi; Paten, Manus
Fonte: University of Chicago Press Publicador: University of Chicago Press
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
56.1%
We propose a new mechanism based on sexual selection to explain the evolution of diet breadth in insects. More specifically, we show that mate choice in females for certain diet-derived male pheromones can be exploited by maternal effect genes that preferentially place offspring on a specific host plant, resulting in specialization. Our analytical model also suggests that the process is more likely to occur with species that show male-congregating mating strategies, such as lekking and hilltopping. The model offers a new explanation for the similarity between the composition of male lepidopteran pheromones and the chemistry of their host plants and also suggests a novel mechanism of host plant shift. This is the first time that sexual selection has been proposed to drive host plant specialization and the first time that a mechanism with selection acting solely on the adult stage has been shown to be capable of determining larval feeding habits.; Organismic and Evolutionary Biology

Seleção de recursos por duas espécies de besouros bruquíneos do gênero gibbobruchusna planta hospedeira bauhinia curvula benth; Resource selection by two species of seed beetles of the genus gibbobruchus in the host plant bauhinia curvula benth

Bergamini, Leonardo Lima
Fonte: Universidade Federal de Goiás; Brasil; UFG; Programa de Pós-graduação em Ecologia e Evolução (ICB); Instituto de Ciências Biológicas - ICB (RG) Publicador: Universidade Federal de Goiás; Brasil; UFG; Programa de Pós-graduação em Ecologia e Evolução (ICB); Instituto de Ciências Biológicas - ICB (RG)
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
66.14%
The process of host-plant selection is the main interface in the herbivore-plant interactions, with deep consequences for the ecology and evolution of those groups. In this work, we investigate some steps of the host-plant selection in two congeneric species of seed beetles. In the first chapter, we assess the oviposition pattern and larval survival in the seed-beetle G. cavillator to evaluate whether oviposition site choices maximize offspring survival, accounting for the spatially hierarchic structure of the system. In the second chapter, we analyze the fine-scale positioning of G. speculifer eggs, and explore the role of geometric constraints in the egg distribution patterns. Altogether our results exemplify how small differences in key traits of the host-plant selection can lead to significant differences in the interaction between herbivore insects and their host plants.; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES; O processo de seleção de plantas hospedeiras é a principal interface nas interações herbívoro-planta, com profundas consequências para a ecologia e evolução destes grupos. Neste trabalho investigamos algumas etapas da seleção de hospedeiras em duas espécies co-genéricas de besouros bruquíneos. No primeiro capítulo avaliamos o padrão de oviposição e de sobrevivência das larvas de G. cavillatorpara testar se as escolhas das fêmeas estão de acordo com as expectativas da teoria de oviposição ótima...

Feeding and oviposition preferences of the diamondback moth Plutella xylostella (Lepidoptera: Plutellidae) on six Brassicaceae host plant species

Newman, Kiera
Fonte: Brock University Publicador: Brock University
Tipo: Electronic Thesis or Dissertation
ENG
Relevância na Pesquisa
66.16%
Plutella xylostella (diamondback moth, DBM) is a globally distributed Lepidopteran that feeds and oviposits almost exclusively on plants in the Brassicaceae family. DBM disperses from the southern United States and Mexico into Canada in the spring and summer. Establishment of DBM in Ontario is partially dependent upon the quantity and quality of host plants available and the preference of DBM for different hosts. Host plants include many crops such as broccoli, canola and cabbage, as well as landscape ornamentals and wild plants. It has previously been established that DBM are attracted to host plants by chemicals, specifically glucosinolates. I examined the preference of DBM among crop, wild and ornamental host plant species and how preference varies with insect life stage (3rd and 4th instar larvae and adults). Experiments included exposing DBM larvae from five populations coming from different locations in Canada to six Brassicaceae species and evaluating the preferences and weight gain over one hour. Then adult females were exposed to these same plant species and their oviposition preferences were examined. Populations from Alberta, Saskatchewan and Ontario were compared to assess differences in preference associated with geographic region or species of host plant. The ultimate goal of my study was to understand the potential of various Brassicaceae species to act as reservoirs to sustain and promote population growth of DBM...

Gene flow in the green mirid, Creontiades dilutus (Hemiptera: Miridae), across arid and agricultural environments with different host plant species

Hereward, J.; Wlter, G.; DeBarro, P.; Lowe, A.; Riginos, C.
Fonte: John Wiley & Sons Ltd Publicador: John Wiley & Sons Ltd
Tipo: Artigo de Revista Científica
Publicado em //2013 EN
Relevância na Pesquisa
66.08%
Creontiades dilutus (Stål), the green mirid, is a polyphagous herbivorous insect endemic to Australia. Although common in the arid interior of Australia and found on several native host plants that are spatially and temporally ephemeral, green mirids also reach pest levels on several crops in eastern Australia. These host-associated dynamics, distributed across a large geographic area, raise questions as to whether (1) seasonal fluctuations in population size result in genetic bottlenecks and drift, (2) arid and agricultural populations are genetically isolated, and (3) the use of different host plants results in genetic differentiation. We sequenced a mitochondrial COI fragment from individuals collected over 24 years and screened microsatellite variation from 32 populations across two seasons. The predominance of a single COI haplotype and negative Tajima D in samples from 2006/2007 fit with a population expansion model. In the older collections (1983 and 1993), a different haplotype is most prevalent, consistent with successive population contractions and expansions. Microsatellite data indicates recent migration between inland sites and coastal crops and admixture in several populations. Altogether, the data suggest that long-distance dispersal occurs between arid and agricultural regions...

Estudo em um fitofago especialista, Tomoplagia reticulata (Diptera:Tephritidae), e sua planta hospedeira, Eremanthus glomerulatus (Asteraceae); A study in an specialist phytophagous, Tomoplagia reticulata (Diptera:Tephritidae), and its host plant, Eremanthus glomerulatus (Asteraceae)

Aluana Gonçalves de Abreu
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 09/02/2009 PT
Relevância na Pesquisa
56.08%
Tomoplagia reticulata (Diptera: Tephritidae) é um fitófago especialista em Eremanthus glomerulatus (Asteraceae). Os adultos ovipõem nas inflorescências da planta hospedeira, onde as larvas se desenvolvem. O histórico de coletas de T. reticulata mostra uma grande variação na quantidade de insetos infestando cada indivíduo de E. glomerulatus. A fim de verificar se a variação no número de herbívoros nas populações do hospedeiro é associada a alguma característica química e/ou genética deste, comparamos as variabilidades genética e química entre indivíduos de E. glomerulatus com diferentes níveis de infestação por T. reticulata (cap. 1). Eremanthus glomerulatus tem baixa variabilidade genética, provavelmente associada à distribuição restrita desta espécie. Apesar da distribuição fragmentada, há pouca estruturação entre as populações desta planta, explicada pelo maior fluxo gênico entre ambientes fragmentados em espécies anemocóricas. As características genéticas e químicas de E. glomerulatus não explicam a variação no nível de herbivoria das populações do hospedeiro. No capítulo 2, testamos a hipótese de que fitófagos especialistas apresentam maior diferenciação genética e menor diversidade do que generalistas...

Effect of Host Plant on the Fecundity of Spittlebug Deois flavopicta Stal (Homoptera: Cercopidae): Implications on Population Dynamics

SUJJI,E.R.; PIRES,C.S.S.; FONTES,E.M.G.; GARCIA,M.A.
Fonte: Sociedade Entomológica do Brasil Publicador: Sociedade Entomológica do Brasil
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2001 EN
Relevância na Pesquisa
56.08%
The spittlebug Deois flavopicta Stal (Hom.: Cercopidae) occurs naturally on native grasses in Central Brazil in low population densities. After the introduction of African grasses, mainly of the genus Brachiaria, for cattle raising, D. flavopicta began to produce population outbreaks and became a pest. Two studies were conducted, aiming to estimate the effects of a native and an exotic host plant on the fecundity of this insect. Females of D. flavopicta maintained during the adult stage on Brachiaria ruziziensis produced more eggs and lived longer than those maintained on Axonopus marginatus (a native grass widely distributed in Brazil), independently of the host plant on which the nymphs were reared. Due to the severe damage produced by adult D. flavopicta on the host plant, the effect of insect density on its own reproductive capacity was evaluated in oviposition cages containing plants of B. ruziziensis, standardized in height and stem number. Densities of one, two, three, four and six couples with virgin females were evaluated. Population densities of three couples, equivalent to 150 adults/m², or higher decreased insect's fecundity. These results contributed to the understanding of the mechanisms that determine low levels of spittlebug populations in the native grasses and promote population outbreaks in introduced ones.

Effect of host plant chemistry on genetic differentiation and reduction of gene flow among Anastrepha fraterculus (Diptera:Tephritidae) populations exploiting sympatric, synchronic hosts

Oroño, Luis Eduardo; Paulin, Laura Elisa; Alberti, Andrea Claudia; Hilal, Mirna Beatriz; Ovruski Alderete, Sergio Marcelo; Vilardi, Juan Cesar; Rull, Juan; Aluja, Martin
Fonte: Entomological Soc Amer Publicador: Entomological Soc Amer
Tipo: info:eu-repo/semantics/article; info:ar-repo/semantics/artículo; info:eu-repo/semantics/publishedVersion Formato: application/pdf
ENG
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56.16%
Herbivore host specialization includes changes in behaviour, driven by locally-induced adaptations to specific plants. These adaptations often result in sexual isolation that can be gauged through detection of reduced gene flow between host associated populations. Hypothetically, reduced gene flow can be mediated both by differential response to specific plant kairomones and by the influence of larval diet on some adult traits such as pheromone composition. These hypotheses could serve as a model to explain rapid radiation of phytophagous tephritid fruit flies, a group that includes several complexes of cryptic species. The South American Fruit Fly Anastrepha fraterculus (Wiedemann) is a complex of at least seven cryptic species among which pheromone mediated sexual isolation resulted in rapid differentiation. Cryptic species also exhibit differences in host affiliation. In search of a model explaining rapid radiation in this group, we studied host plant chemical composition and genetic structure of three host associated sympatric populations of A. fraterculus. Chemical composition among host plant fruit varied widely both for nutrient and potentially toxic secondary metabolite content. Adaptation to plant chemistry appears to have produced population differentiation. We found host mediated differentiation to be stronger between populations exploiting sympatric synchronic hosts differing in chemical composition...

Análises genômicas de Methylobacterium mesophilicum SR1.6/6 com ênfase na interação com a planta hospedeira.; Genomic analyzes of Methylobacterium mesophilicum SR1.6/6 with emphasis on the interaction with the host plant.

Neves, Aline Aparecida Camargo das
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 30/07/2015 PT
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Bactérias do gênero Methylobacterium são encontradas em associação com espécies vegetais, onde são capazes de promover o crescimento, aumentar a atividade fotossintética e reduzir o ataque de patógenos ao hospedeiro. Além de conferir estas vantagens para a planta hospedeira, estas bactérias podem também produzir biopolímeros (PHA e PHB). Desta forma, o objetivo deste trabalho foi anotar o genoma de Methylobacterium mesophilicum SR1.6/6 e avaliar o seu transcriptoma em estágios iniciais de interação com Citrus sinensis. A análise do genoma mostrou que SR1.6/6 pode produzir auxina, reduzir o estresse da planta alterando os níveis de etileno, apresenta sistema de monitoramento de populacional pelo sistema quorum sensing (QS) e um metabolismo metilotrófico completo. A análise do transcriptoma evidenciou que os exsudatos radiculares de C. sinensis induzem a expressão de genes de resposta ao estresse oxidativo, seguido da indução de genes de adesão e biofilme durante a colonização da planta hospedeira. A interação entre M. mesophilicum SR1.6/6 e a planta hospedeira envolve mecanismos de reconhecimento e adaptação ao estresse, antes mesmo de ocorrer o primeiro contato físico entre a célula bacteriana e a planta hospedeira...

Host plant selection by a monophagous herbivore is not mediated by quantitative changes in unique plant chemistry : Agonopterix alstroemeriana and Conium maculatum

Castells Caballé, Eva; Berenbaum, M.R.
Fonte: Universidade Autônoma de Barcelona Publicador: Universidade Autônoma de Barcelona
Tipo: Artigo de Revista Científica Formato: application/pdf
Publicado em //2008 ENG
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Host plant selection by ovipositing females is a key process determining the success of phytophagous insects. In oligophagous lepidopterans, host-specific plant secondary chemicals are expected to be dominant factors governing oviposition behavior; distinctive compounds can serve as high-contrast signals that clearly differentiate confamilial hosts from non-hosts increasing the accuracy of host quality evaluation. Agonopterix alstroemeriana (Clerk) (Lepidoptera: Oecophoridae) and Conium maculatum L. (Apiaceae) form an extremely specialized plant-herbivore system, with A. alstroemeriana monophagous on C. maculatum, a plant with few other insect herbivores at least in part due to its virtually unique capacity among plants to produce piperidine alkaloids. Here we have studied the response of A. alstroemeriana oviposition to unique host plant secondary metabolites, piperidine alkaloids, and widespread compounds, mono- and sesquiterpenes, in a concentration-dependent fashion. Rates of oviposition were negatively correlated with Z-ocimene concentrations. To confirm the deterrent properties of this monoterpene for A. alstroemeriana oviposition, we conducted a choice experiment using artificially damaged C. maculatum plants, with higher emission of volatiles...