771 resultados para SPIDER PARASITOID


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Comic books, graphic narrative and sequential art, had their origin in newspapers, in the period of the Industrial Revolution. First published weekly in the comic strip format, with the passage of time, the new form of literature has gained more and more public and comic strips became complete stories in the format of comic books and later, graphic novels. This course's final paper aims to present the main components of comics: the picture and the text; and to examine the way in which these two elements overlap and complement each other in the configuration of comics as a whole. As the object of analysis, it was chosen the graphic novel Spider-Man: Blue, first published in 2002 as part of a project composed by three other titles from the double winning cartoonists of the Eisner Award, Jeph Loeb and Tim Sale. For theoretical background, was chosen the book Os Quadrinhos - Linguagem e Semiótica: Um Estudo Abrangente da Arte Sequencial written by the researcher Antonio Luiz Cagnin, which presents a study of all components found in the sequential art and treated in this work: the narrative time, visual plans, balloons, caption, and onomatopoeia

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Pós-graduação em Biofísica Molecular - IBILCE

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Comic books, graphic narrative and sequential art, had their origin in newspapers, in the period of the Industrial Revolution. First published weekly in the comic strip format, with the passage of time, the new form of literature has gained more and more public and comic strips became complete stories in the format of comic books and later, graphic novels. This course's final paper aims to present the main components of comics: the picture and the text; and to examine the way in which these two elements overlap and complement each other in the configuration of comics as a whole. As the object of analysis, it was chosen the graphic novel Spider-Man: Blue, first published in 2002 as part of a project composed by three other titles from the double winning cartoonists of the Eisner Award, Jeph Loeb and Tim Sale. For theoretical background, was chosen the book Os Quadrinhos - Linguagem e Semiótica: Um Estudo Abrangente da Arte Sequencial written by the researcher Antonio Luiz Cagnin, which presents a study of all components found in the sequential art and treated in this work: the narrative time, visual plans, balloons, caption, and onomatopoeia

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Pós-graduação em Biofísica Molecular - IBILCE

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Animals present an enormous variety of behavioural defensive mechanisms, which increase their survival, but often at a cost. Several animal taxa reduce their chances of being detected and/or recognized as prey items by freezing (remaining completely motionless) in the presence of a predator. We studied costs and benefits of freezing in immature Eumesosoma roeweri (Opiliones, Sclerosomatidae). Preliminary observations showed that these individuals often freeze in the presence of the syntopic predatory spider Schizocosa ocreata (Araneae, Lycosidae). We verified that harvestmen paired with predators spent more time freezing than when alone or when paired with a conspecific. Then. we determined that predator chemical cues alone did not elicit freezing behaviour. Next, we examined predator behaviour towards moving/non-moving prey and found that spiders attacked moving prey significantly more, suggesting an advantage of freezing in the presence of a predator. Finally, as measure of the foraging costs of freezing, we found that individuals paired with a predator for 2 h gained significantly less weight than individuals paired with a conspecific or left alone. Taken together, our results suggest that freezing may protect E. roeweri harvestmen from predatory attacks by wolf spiders, but at the cost of reduced food and/or water intake. (C) 2009 Elsevier B.V. All rights reserved.

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Stereotyped behaviors have been routinely used as characters for phylogeny inference, but the same cannot be said of the plastic aspects of performance, which routinely are taken as a result of ecological processes. In this paper we examine the evolution of one of these plastic behavioral phenotypes, thus fostering a bridge between ecological and evolutionary processes. Foraging behavior in spiders is context dependent in many aspects, since it varies with prey type and size, spider nutritional and developmental state, previous experience and, in webweavers, is dependent on the structure of the web. Reeling is a predatory tactic typical of cobweb weavers (Theridiidae), in which the spider moves the prey toward her by pulling the capture thread (gumfoot) to which it is adhered. Predatory reeling is dependent on the gumfoot for its expression, and has not been previously reported in orbweavers. In order to investigate the evolution of this web dependent behavior, we built artificial, pseudogumfoot lines in orbwebs and registered parameters of the predatory tactics in this modified web. Aspects of the predatory tactics of 240 individuals (12 species in 4 families) were measured, and the resulting data were optimized on the phylogeny of Orbiculariae. All species perform predatory reeling with the pseudogumfoot lines. Thus, predatory reeling is homologous for the whole Orbiculariae group. In nature, holes made by insects in ecribellate orbs produce pseudogumfoot lines (similar to out experimentally modified webs), and thus reeling occurred naturally in ecribellates. Nevertheless, outside lab conditions, predatory reeling does not occur among cribellate orbweavers, so that this behavior could not have been selected for in the cribellate ancester of orbweavers. Cribellate spiders are flexible enough as to present novel and adaptive predatory responses (reeling) even when exposed for the first time to conditions outside their usual environment. Thus, the evolution of reeling suggests and alternative mechanism for the production of evolutionary novelties; that is, the exploration of unusual ecological conditions and of the regular effects these abnormal conditions have on phenotype expression.

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The larval endoparasitoid Toxoneuron nigriceps (Viereck) (Hymenoptera: Braconidae) has a toolbox of biological weapons to secure for host colonization and the successful parasitization of its host Heliothis virescens (F.) (Lepidoptera: Noctuidae). The cDNA of a putative chitinase has been previously isolated and initially characterized from teratocytes of this parasitoid among the plethora of molecules available in the venom and calyx fluids injected by females, oral and/or anal secretions released by the parasitoid larvae and/or produced by the expression of genes of the symbiotic associated polydnavirus. This putative chitinase has been initially associated with the host cuticle digestion to allow for parasitoid egression and with the asepsis of the host environment, acting as an antimicrobial. As chitinases are commonly expressed in plants against plant pathogens, the chitinase derived from the teratocytes of T. nigriceps is a potential tool for the development of insect pest control methods based on the disruption of the perithrophic membrane of herbivores. Therefore, we aimed to characterize the activity of the putative chitinase from teratocytes of T. nigriceps (Tnchi) produced using the Escherichia coli expression system and its potential to control H. virescens larvae when expressed into transgenic tobacco plants. The purified E. coli-produced Tnchi protein showed no chitinolitic activity, but was active in binding with colloidal and crystalline chitins in water and with colloidal chitin in buffered solution (pH = 6.74). Transgenic tobacco plants showed no enhanced chitinolitic activity relative to control plants, but survival of three-day old larvae of H. virescens was severely affected when directly fed on transgenic tobacco leaves expressing the recombinant Tnchi protein. Some properties of the Tnchi protein and the potential use of Tnchi-transgenic plants to control plant pests are discussed. (c) 2012 Elsevier Inc. All rights reserved.

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Preliminary observations of the harvestman Leiobunum vittatum found that individuals rub their bodies against the substrate, presenting the possibility of chemical marking. To determine whether or not L. vittatum individuals can detect substrate-borne chemical cues, we compared responses of L. vittatum males and females to substrate-borne male and female cues. We found that individuals of L. vittatum do respond to conspecific cues and that their responses are sex-specific. In response to substrate-borne conspecific cues, male L. vittatum spent more time, engaged in more scraping with their sensory legs I, and engaged in pedipalpal tapping more often in the presence versus absence of conspecific cues (male and female equally). Furthermore, in the presence of conspecific cues, males engaged in two behaviors never observed in females-(a) "fast approach" and (b) "jerking", the latter of which was never observed in the presence of cricket cues. In contrast to males, females did not spend more time on conspecific cues, but did spend more time tapping their pedipalps in the presence of male vs female cues, suggesting an ability to distinguish between them. A final experiment explored the possibility that females could discriminate among males of varying histories of agonistic interactions based upon their chemical cues. We found no support for this hypothesis. Our results demonstrate that L. vitattum do respond to conspecific cues, and introduce the possibility that intraspecific communication may be mediated in part by chemical cues.

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In order to succeed in biological control programs, not only is it crucial to understand the number of natural enemies to be released but also on how many sites per area this releasing must be performed. These variables might differ deeply among egg parasitoid species and crops worked. Therefore, these trials were carried out to evaluate the parasitism (%) in eggs of Anticarsia gemmatalis and Pseudoplusia includens after the release of different densities of the egg parasitoid Trichogramma pretiosum. Field dispersal was also studied, in order to determine appropriate recommendations for the release of this parasitoid in soybean fields. The regression analysis between parasitism (%) and densities of the parasitoid indicated a quadratic effect for both A. gemmatalis and P. includens. The maximum parasitism within 24 h after the release was reached with densities of 25.6 and 51.2 parasitoids per host egg, respectively, for the two pests. Parasitism of T. pretiosum in eggs of P. includens decreased linearly as the distance of the pest eggs from the parasitoid release sites increased. For P. includens, the mean radius of T. pretiosum action and the area of parasitoid dispersal in the soybean crop were 8.01 m and 85.18 m(2), respectively. We conclude that for a successful biological control program of lepidopteran pests using T. pretiosum in soybean fields, a density of 25.6 parasitoids per host egg, divided into 117 sites per hectare, should be used.

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We investigated the possibility of reproductive interference between two sibling spider species, Paratrechalea azul and Paratrechalea ornata, which occur syntopically and reproduce synchronously. Males of both species offer a nuptial gift composed of prey wrapped in silk to females. Through laboratory experiments, we evaluated possible asymmetries in the outcome of heterospecific encounters between males and females, and investigated whether chemical signalling could function as a premating barrier between the two species. Males of P. azul were unable to discriminate conspecific from heterospecific female draglines, which resulted in wasted time and energy in nuptial gift construction. Males of P. ornata incurred a higher cost for discrimination mistakes because most of them were attacked by heterospecific females; 95% lost the nuptial gift upon the attack and 33% were preyed upon. This pattern is probably a consequence of differences in body size between males and females of each species. Both species showed erroneous female choice, but only P. ornata females courted heterospecific males, which are considerably larger than conspecific males and may resemble high-quality mating partners. Males of P. ornata also made discrimination mistakes, but at a much lower frequency compared to P. azul males. The selective pressure for precise recognition of conspecific female signs is probably stronger on P. ornata males because misdirected courtship may increase their chances of encountering predatory heterospecific females. This study provides the first detailed evidence of reproductive interference between two reproductively isolated spider species, showing that the costs paid by individuals of different sexes and different species are highly asymmetric. (C) 2012 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

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The present study describes different preimaginal stages of Trypoxylon rogenhoferi examined by Scanning Electron Microscopy (SEM) and compares the results with observations on closely related species. Some notes on the nesting habits of this species, including their spider prey, nest parasites, and development time are provided. In short, T. rogenhoferi proved quite similar to the previous report on T. albitarse although SEM images are rarely presented in such descriptions. In fact the present study emphasized the importance of SEM images to describe fine morphological details that can be useful characters for taxonomic and phylogenetic studies. Images of some earlier development stages (first and second larval instar and egg) are presented for the first time, and compared with the few available data from other hymenopterans.

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Gomesin (Gm) was the first antimicrobial peptide (AMP) isolated from the hemocytes of a spider, the Brazilian mygalomorph Acanthoscurria gomesiana. We have been studying the properties of this interesting AMP, which also displays anticancer, antimalarial, anticryptococcal and anti-Leishmania activities. In the present study, the total syntheses of backbone-cyclized analogues of Gm (two disulfide bonds), [Cys(Acm)2,15]-Gm (one disulfide bond) and [Thr2,6,11,15,d-Pro9]-Gm (no disulfide bonds) were accomplished, and the impact of cyclization on their properties was examined. The consequence of simultaneous deletion of pGlu1 and Arg16-Glu-Arg18-NH2 on Gm antimicrobial activity and structure was also analyzed. The results obtained showed that the synthetic route that includes peptide backbone cyclization on resin was advantageous and that a combination of 20% DMSO/NMP, EDC/HOBt, 60?degrees C and conventional heating appears to be particularly suitable for backbone cyclization of bioactive peptides. The biological properties of the Gm analogues clearly revealed that the N-terminal amino acid pGlu1 and the amidated C-terminal tripeptide Arg16-Glu-Arg18-NH2 play a major role in the interaction of Gm with the target membranes. Moreover, backbone cyclization practically did not affect the stability of the peptides in human serum; it also did not affect or enhanced hemolytic activity, but induced selectivity and, in some cases, discrete enhancements of antimicrobial activity and salt tolerance. Because of its high therapeutic index, easy synthesis and lower cost, the [Thr2,6,11,15,d-Pro9]-Gm analogue remains the best active Gm-derived AMP developed so far; nevertheless, its elevated instability in human serum may limit its therapeutic potential. Copyright (c) 2012 European Peptide Society and John Wiley & Sons, Ltd.

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In response to herbivore attack, plants release herbivore-induced plant volatiles (HIPVs) that represent important chemical cues for herbivore natural enemies. Additionally, HIPVs have been shown to mediate other ecological interactions with herbivores. Differently from natural enemies that are generally attracted to HIPVs, herbivores can be either attracted or repelled depending on several biological and ecological parameters. Our study aimed to assess the olfactory response of fall armyworm-mated female moths toward odors released by mechanically and herbivore-induced corn at different time intervals. Results showed that female moths strongly respond to corn volatiles, although fresh damaged corn odors (0-1 h) are not recognized by moths. Moreover, females preferred volatiles released by undamaged plant over herbivore-induced plants at 5-6 h. This preference for undamaged plants may reflect an adaptive strategy of moths to avoid competitors and natural enemies for their offspring. We discussed our results based on knowledge about corn volatile release pattern and raise possible explanations for fall armyworm moth behavior.

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Egg parasitism of Trichogramma pretiosum strain RV when presented with eggs of Anticarsia gemmatalis and Pseudoplusia includens was investigated at 18, 20, 22, 25, 28, 30 and 32 degrees C. The number of eggs parasitized per day decreased for both hosts as a function of the age of parasitoids, reaching 80% of lifetime parasitism more rapidly as temperature increased; on the 4th day at 32 degrees C and on the 12th day at 18 degrees C. The lifetime number of parasitized P. includens eggs achieved by the parasitoid maintained at 20 degrees C (44.95 +/- 3.94) differed from the results recorded at 32 degrees C (28.5 +/- 1.33). Differently, the lifetime number of A. gemmatalis parasitized eggs did not differ among the temperatures. When T. pretiosum reached 100% of lifetime parasitism, each adult female had parasitized from 28.5 +/- 1.33 to 44.95 +/- 3.94 and from 29.58 +/- 2.80 to 45.36 +/- 4.50 P. includens and A. gemmatalis eggs, respectively. Also, the longevity of these adult T. pretiosum females, for which P. includens or A. gemmatalis eggs were offered, was inversely correlated with temperature. Not only were the survival curves of those adult T. pretiosum females of type I when they were presented with eggs of A. gemmatalis but also with eggs of P. includens, i.e., there was an increase in the mortality rate with time as the temperature increased. In conclusion, T. pretiosum strain RV parasitism was impacted by temperature when on both host eggs; however, the parasitoid still exhibited high survival and, more importantly, high number of parasitized A. gemmatalis and P. includens eggs even at the extremes tested temperatures of 18 and 32 degrees C. Those results indicate that T. pretiosum strain RV might be well adapted to this studied temperature range and, thus, be potentially suitable for use in biological control programs of P. includens and A. gemmatalis in different geographical areas that fits in this range. It is important to emphasize the results here presented are from laboratory studies and, therefore, field trials still need to be carried out in the future with this strain in order to support the full development of the technology intend to use this egg parasitoid in soybean fields worldwide. (C) 2011 Elsevier Inc. All rights reserved.

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Five species of Ctenus from the Amazon basin are redescribed: C. delesserti (Caporiacco, 1947), C. falconensis Schenkel, 1953, C. nigritus F.O. Pickard-Cambridge, 1897, C. serratipes F.O. Pickard-Cambridge, 1897 and C. sigma (Schenkel, 1953). Three new synonymies are proposed: Ctenus fulvipes Caporiacco, 1947, C. itatiayaeformis Caporiacco, 1955 and C. scenicus Caporiacco, 1947 with C. serratipes. The female of Ctenus nigritus is described for the first time. The distributional ranges of Ctenus nigritus and C. serratipes are extended. We also present distributional maps of the five redescribed species.