Home OALib Journal OALib PrePrints Submit Ranking News My Lib FAQ About Us Follow Us+
 Title Keywords Abstract Author All
Search Results: 1 - 10 of 100 matches for " "
 Page 1 /100 Display every page 5 10 20 Item
 PLOS ONE , 2012, DOI: 10.1371/journal.pone.0043607 Abstract: Plants release volatiles induced by herbivore feeding that may affect the diversity and composition of plant-associated arthropod communities. However, the specificity and role of plant volatiles induced during the early phase of attack, i.e. egg deposition by herbivorous insects, and their consequences on insects of different trophic levels remain poorly explored. In olfactometer and wind tunnel set-ups, we investigated behavioural responses of a specialist cabbage butterfly (Pieris brassicae) and two of its parasitic wasps (Trichogramma brassicae and Cotesia glomerata) to volatiles of a wild crucifer (Brassica nigra) induced by oviposition of the specialist butterfly and an additional generalist moth (Mamestra brassicae). Gravid butterflies were repelled by volatiles from plants induced by cabbage white butterfly eggs, probably as a means of avoiding competition, whereas both parasitic wasp species were attracted. In contrast, volatiles from plants induced by eggs of the generalist moth did neither repel nor attract any of the tested community members. Analysis of the plant’s volatile metabolomic profile by gas chromatography-mass spectrometry and the structure of the plant-egg interface by scanning electron microscopy confirmed that the plant responds differently to egg deposition by the two lepidopteran species. Our findings imply that prior to actual feeding damage, egg deposition can induce specific plant responses that significantly influence various members of higher trophic levels.
 Florian P. Schiestl Frontiers in Ecology and Evolution , 2014, DOI: 10.3389/fevo.2014.00010 Abstract: Positive correlations between volatile organic compounds (VOCs) and defense chemicals indicate signaling of defense status. Such aposematic signaling has been hypothesized to be widespread in plants, however, it has up to now only been shown for visual signals. Correlations between identical compounds in different plant tissues, on the other hand, can be informative about the (co-)regulation of their biosynthesis or emission. Here I use Brassica rapa to investigate (1) correlations between identical metabolites (volatiles, glucosinolates) in leaf and flower tissue, and (2) correlations between volatiles and glucosinolates in the same plant organs (flowers and leaves). Whereas the amounts of many glucosinolates were positively correlated in leaves and flower tissue, identical leaf, and floral VOCs showed no such correlations, indicating independent regulation of emission. None of the leaf or flower volatiles showed positive correlations with the two major glucosinolates (gluconapin, glucobrassicanapin) or the sum of all glucosinolates in either leaves or flowers. Some VOCs, however, showed positive correlations with minor glucosinolates which, however, represented less than one percent of the total amounts of glucosinolates. Some leaf monoterpenes showed negative associations with gluconapin. The lack of consistent positive correlations between VOCs and major defense compounds suggests that plants do not chemically signal their defense status. This could be adaptive as it may avoid eavesdropping by specialist herbivores to locate their host plants. Negative correlations likely indicate chemical trade-offs in the synthesis of secondary metabolites.
 田厚军,林,硕,陈,勇,陈艺欣,赵建伟,魏,辉 - , 2018, DOI: 10.7606/j.issn.1004-1389.2018.04.018 Abstract: 为了研究小菜蛾对植物挥发物的行为反应与抗性水平之间的关系，采用昆虫Y形嗅觉仪，测定氰戊菊酯抗性和敏感品系小菜蛾雌成虫对15种植物挥发性物质的行为反应。结果表明：抗性品系小菜蛾和敏感品系小菜蛾均对5种绿叶气味（反-2-己烯醛、顺-3-己烯醇、顺-3-己烯乙酸酯、正己醇和正己醛）以及苯甲醛、桉树脑的趋向反应率显著高于石蜡油（P<0.05， χ检验），表明这7种物质对小菜蛾雌蛾均有一定的诱集作用。在8种萜烯类物质中，敏感小菜蛾雌蛾分别对2种物质（牻牛儿醇、D-柠檬烯）的趋向反应率与石蜡油间显著差异（P＞0.05， χ检验）；而抗性小菜蛾雌蛾分别对4种物质（牻牛儿醇、(R)-(-)-香芹酮、里那醇、(1R)-(+)-α-蒎烯）的趋向反应率与石蜡油均显著差异。抗性品系小菜蛾停留在Y形管主臂上的比例均少于敏感品系，与敏感品系相比，在较低的氰戊菊酯抗性种群水平下（6.52倍），并没有显著改变小菜蛾雌蛾对寄主植物挥发物的行为反应趋势，但是抗性水平下却加剧小菜蛾趋向反应的比率。In order to study the relationship between behavior responses of diamondback moth［(Plutella xylostella(L.)］ to plants volatiles and resistance to fenvalerate,Y-tube olfactormeter was employed to measure behaviour responses of susceptible strain(S strain) and fenvalerate resistant strain(Fen-R strain) of the female moth to fifteen plant volatiles. The results showed that both strains of the moth had significantly higher reaction to five odors of green leaf(trans-2-hexen-1-al,hexanal,1-hexanol,cis-3-hexen-1-ol,cis-3-hexenyl acetate),benzaldehyde and eucalyptol compared with paraffin(P<0.05, χ-test),which indicated that these seven matters could trap diamondback moth in some degree. In eight kinds of terpenes,the tendency responses rate of the S strain has no significant difference between two substances(d-limonene and geraniol) and paraffin; and the tendency responses rate of the Fen-R strain had no significant difference between four substances(geraniol,(R)-(-)-carvone,linalool,(-)-α-pinene) and paraffin. The quantitative proportion of the Fen-R strain stayed at the Y-tube was less than the S strain. Compared with S strain,under the condition of lower fenvalerate resistance population(6.52 times),the behavior reaction trend of diamondback moth to host plants volatile matters did not change significantly,but the quantitative proportion of diamondback moth which had taxis reaction increased at the resistant level. Together,these results would provide experimental basis for screening insect sex pheromone synergists.
 PLOS ONE , 2007, DOI: 10.1371/journal.pone.0001081 Abstract: Background Plants defend themselves against herbivorous insects, utilizing both constitutive and inducible defenses. Induced defenses are controlled by several phytohormone-mediated signaling pathways. Here, we analyze transcriptional changes in the North American Arabidopsis relative Boechera divaricarpa in response to larval herbivory by the crucifer specialist lepidopteran Plutella xylostella (diamondback moth) and by the generalist lepidopteran Trichoplusia ni (cabbage semilooper), and compare them to wounding and exogenous phytohormone application. Methodology/Principal Findings We use a custom macroarray constructed from B. divaricarpa herbivory-regulated cDNAs identified by suppression subtractive hybridization and from known stress-responsive A. thaliana genes for transcript profiling after insect herbivory, wounding and in response to jasmonate, salicylate and ethylene. In addition, we introduce path analysis as a novel approach to analyze transcript profiles. Path analyses reveal that transcriptional responses to the crucifer specialist P. xylostella are primarily determined by direct effects of the ethylene and salicylate pathways, whereas responses to the generalist T. ni are influenced by the ethylene and jasmonate pathways. Wound-induced transcriptional changes are influenced by all three pathways, with jasmonate having the strongest effect. Conclusions/Significance Our results show that insect herbivory is distinct from simple mechanical plant damage, and that different lepidopteran herbivores elicit different transcriptional responses.
 H. Bechmann-Pasquinucci Physics , 2005, DOI: 10.1103/PhysRevA.73.044305 Abstract: In quantum cryptography the optimal eavesdropping strategy requires that the eavesdropper uses quantum memories in order to optimize her information. What happens if the eavesdropper has no quantum memory? It is shown that the best strategy is actually to adopt the simple intercept/resend strategy.
 Qing-yu Cai Physics , 2004, DOI: 10.1103/PhysRevLett.91.109801 Abstract: Attack the ping-pong protocol without eavesdropping.
 Computer Science , 2009, DOI: 10.1109/TSP.2010.2046593 Abstract: This paper presents greedy gossip with eavesdropping (GGE), a novel randomized gossip algorithm for distributed computation of the average consensus problem. In gossip algorithms, nodes in the network randomly communicate with their neighbors and exchange information iteratively. The algorithms are simple and decentralized, making them attractive for wireless network applications. In general, gossip algorithms are robust to unreliable wireless conditions and time varying network topologies. In this paper we introduce GGE and demonstrate that greedy updates lead to rapid convergence. We do not require nodes to have any location information. Instead, greedy updates are made possible by exploiting the broadcast nature of wireless communications. During the operation of GGE, when a node decides to gossip, instead of choosing one of its neighbors at random, it makes a greedy selection, choosing the node which has the value most different from its own. In order to make this selection, nodes need to know their neighbors' values. Therefore, we assume that all transmissions are wireless broadcasts and nodes keep track of their neighbors' values by eavesdropping on their communications. We show that the convergence of GGE is guaranteed for connected network topologies. We also study the rates of convergence and illustrate, through theoretical bounds and numerical simulations, that GGE consistently outperforms randomized gossip and performs comparably to geographic gossip on moderate-sized random geometric graph topologies.
 Physics , 2004, Abstract: The eavesdropping scheme proposed by W\'{o}jcik [Phys. Rev. Lett. {\bf 90},157901(2003)] on the quantum communication protocol of Bostr\"{o}m and Felbinger [Phys. Rev. Lett. {\bf 89}, 187902(2002)] is improved by constituting a new set of attack operations. The improved scheme only induces half of the eavesdropping losses in W\'{o}jcik's scheme, therefore, in a larger domain of the quantum channel transmission efficiency $\eta$, i.e., [0,75%], the eavesdropper Eve can attack all the transmitted bits. Comparing to W\'{o}jcik's scheme, in the improved scheme the eavesdropping (legitimate) information gain does not vary in the $\eta$ domain of [0, 50%], while in the $\eta$ domain of (50%, 75%] the less eavesdropping losses induce more eavesdropping information gains, for Eve can attack {\it all} the transmitted bits and accordingly eavesdropping information gains do {\it not} decrease. Moreover, for the Bostr\"{o}m-Felbinger protocol, the insecurity upper bound of $\eta$ presented by W\'{o}jcik is pushed up in the this paper, that is, according to W\'{o}jcik's eavesdropping scheme, the Bostr\"{o}m-Felbinger protocol is not secure for transmission efficiencies lower than almost 60%, while according to the improved scheme, it is not secure for transmission efficiencies lower than almost 80%.
 Computer Science , 2012, DOI: 10.1016/j.ipl.2013.03.008 Abstract: In semiquantum key-distribution (Boyer et al.) Alice has the same capability as in BB84 protocol, but Bob can measure and prepare qubits only in $\{|0\rangle, |1\rangle\}$ basis and reflect any other qubit. We study an eavesdropping strategy on this scheme that listens to the channel in both the directions. With the same level of disturbance induced in the channel, Eve can extract more information using our two-way strategy than what can be obtained by the direct application of one-way eavesdropping in BB84.
 Physics , 2001, Abstract: An undetected eavesdropping attack must produce count rate statistics that are indistinguishable from those that would arise in the absence of such an attack. In principle this constraint should force a reduction in the amount of information available to the eavesdropper. In this paper we illustrate, by considering a particular class of eavesdropping attacks, how the general analysis of this problem may proceed.
 Page 1 /100 Display every page 5 10 20 Item