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Sample records for winged aphid morphs

  1. Multiple cues for winged morph production in an aphid metacommunity.

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    Mohsen Mehrparvar

    Full Text Available Environmental factors can lead individuals down different developmental pathways giving rise to distinct phenotypes (phenotypic plasticity. The production of winged or unwinged morphs in aphids is an example of two alternative developmental pathways. Dispersal is paramount in aphids that often have a metapopulation structure, where local subpopulations frequently go extinct, such as the specialized aphids on tansy (Tanacetum vulgare. We conducted various experiments to further understand the cues involved in the production of winged dispersal morphs by the two dominant species of the tansy aphid metacommunity, Metopeurum fuscoviride and Macrosiphoniella tanacetaria. We found that the ant-tended M. fuscoviride produced winged individuals predominantly at the beginning of the season while the untended M. tanacetaria produced winged individuals throughout the season. Winged mothers of both species produced winged offspring, although in both species winged offspring were mainly produced by unwinged females. Crowding and the presence of predators, effects already known to influence wing production in other aphid species, increased the percentage of winged offspring in M. tanacetaria, but not in M. fuscoviride. We find there are also other factors (i.e. temporal effects inducing the production of winged offspring for natural aphid populations. Our results show that the responses of each aphid species are due to multiple wing induction cues.

  2. Orco mediates olfactory behaviors and winged morph differentiation induced by alarm pheromone in the grain aphid, Sitobion avenae.

    Science.gov (United States)

    Fan, Jia; Zhang, Yong; Francis, Frédéric; Cheng, Dengfa; Sun, Jingrun; Chen, Julian

    2015-09-01

    Olfaction is crucial for short distance host location and pheromone detection by insects. Complexes of olfactory receptors (ORs) are composed of odor-specific ORs and OR co-receptors (Orco). Orcos are widely co-expressed with odor-specific ORs and are conserved across insect taxa. A number of Orco orthologs have been studied to date, although none has been identified in cereal aphids. In this study, an Orco gene ortholog was cloned from the grain aphid, Sitobion avenae, and named "SaveOrco"; RNA interference (RNAi) reduced the expression of SaveOrco to 34.11% in aphids, resulting in weaker EAG (electroantennogram) responses to plant volatiles (Z-3-hexene-1-ol; methyl salicylate, MeSA) and aphid alarm pheromone (E-β-farnesene, EBF). Aphid wing differentiation induced by EBF was investigated in both RNAi treated and untreated aphids. EBF induced production of winged aphids in both pre-natal and post-natal periods in untreated aphids, but no such induction was observed in the RNAi-treated aphids. We conclude that SaveOrco is crucial for the aphid's response to pheromones and other volatiles, and is involved in wing differentiation triggered by EBF. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Research of Morphing Wing Efficiency

    National Research Council Canada - National Science Library

    Komarov, Valery

    2004-01-01

    This report results from a contract tasking Samara State Aerospace University (SSAU) as follows: The contractor will develop and investigate aerodynamic and structural weight theories associated with morphing wing technology...

  4. Drag Performance of Twist Morphing MAV Wing

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    Ismail N.I.

    2016-01-01

    Full Text Available Morphing wing is one of latest evolution found on MAV wing. However, due to few design problems such as limited MAV wing size and complicated morphing mechanism, the understanding of its aerodynamic behaviour was not fully explored. In fact, the basic drag distribution induced by a morphing MAV wing is still remained unknown. Thus, present work is carried out to compare the drag performance between a twist morphing wing with membrane and rigid MAV wing design. A quasi-static aeroelastic analysis by using the Ansys-Fluid Structure Interaction (FSI method is utilized in current works to predict the drag performance a twist morphing MAV wing design. Based on the drag pattern study, the results exhibits that the morphing wing has a partial similarities in overall drag pattern with the baseline (membrane and rigid wing. However, based CD analysis, it shows that TM wing induced higher CD magnitude (between 25% to 82% higher than to the baseline wing. In fact, TM wing also induced the largest CD increment (about 20% to 27% among the wings. The visualization on vortex structure revealed that TM wing also produce larger tip vortex structure (compared to baseline wings which presume to promote higher induce drag component and subsequently induce its higher CD performance.

  5. Antibiotics, primary symbionts and wing polyphenism in three aphid species.

    Science.gov (United States)

    Hardie, Jim; Leckstein, Peter

    2007-08-01

    The possible role of the primary Buchnera symbionts in wing polyphenism is examined in three aphid species. Presumptive winged aphids were fed on antibiotic-treated beans to destroy these symbionts. As previously reported, this leads to inhibited growth and low/zero fecundity. When such treatment is applied to the short-day-induced gynoparae (the winged autumn migrant) of the black bean aphid, Aphis fabae, it also causes many insects to develop as wingless or winged/wingless intermediate adult forms (apterisation). However, whilst antibiotic treatment of crowd-induced, long-day winged forms of the pea aphid, Acyrthosiphon pisum (a green and a pink clone) and the vetch aphid, Megoura viciae has similar effects on size and fecundity, it does not affect wing development. Food deprivation also promotes apterisation in A. fabae gynoparae but not in the crowd-induced winged morphs of the other two species. Thus, it appears that apterisation in A. fabae is not a direct effect of antibiotic treatment or a novel role for symbionts but is most likely related to impaired nutrition induced by the loss of the symbiont population.

  6. Role of wing morphing in thrust generation

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    Mehdi Ghommem

    2014-01-01

    Full Text Available In this paper, we investigate the role of morphing on flight dynamics of two birds by simulating the flow over rigid and morphing wings that have the characteristics of two different birds, namely the Giant Petrel and Dove Prion. The simulation of a flapping rigid wing shows that the root of the wing should be placed at a specific angle of attack in order to generate enough lift to balance the weight of the bird. However, in this case the generated thrust is either very small, or even negative, depending on the wing shape. Further, results show that morphing of the wing enables a significant increase in the thrust and propulsive efficiency. This indicates that the birds actually utilize some sort of active wing twisting and bending to produce enough thrust. This study should facilitate better guidance for the design of flapping air vehicles.

  7. Analysis of bat wings for morphing

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    Leylek, Emily A.; Manzo, Justin E.; Garcia, Ephrahim

    2008-03-01

    The morphing of wings from three different bat species is studied using an extension of the Weissinger method. To understand how camber affects performance factors such as lift and lift to drag ratio, XFOIL is used to study thin (3% thickness to chord ratio) airfoils at a low Reynolds number of 100,000. The maximum camber of 9% yielded the largest lift coefficient, and a mid-range camber of 7% yielded the largest lift to drag ratio. Correlations between bat wing morphology and flight characteristics are covered, and the three bat wing planforms chosen represent various combinations of morphological components and different flight modes. The wings are studied using the extended Weissinger method in an "unmorphed" configuration using a thin, symmetric airfoil across the span of the wing through angles of attack of 0°-15°. The wings are then run in the Weissinger method at angles of attack of -2° to 12° in a "morphed" configuration modeled after bat wings seen in flight, where the camber of the airfoils comprising the wings is varied along the span and a twist distribution along the span is introduced. The morphed wing configurations increase the lift coefficient over 1000% from the unmorphed configuration and increase the lift to drag ratio over 175%. The results of the three different species correlate well with their flight in nature.

  8. Aphid wing induction and ecological costs of alarm pheromone emission under field conditions.

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    Eduardo Hatano

    2010-06-01

    Full Text Available The pea aphid, Acyrthosiphon pisum Harris, (Homoptera: Aphididae releases the volatile sesquiterpene (E-beta-farnesene (EBF when attacked by a predator, triggering escape responses in the aphid colony. Recently, it was shown that this alarm pheromone also mediates the production of the winged dispersal morph under laboratory conditions. The present work tested the wing-inducing effect of EBF under field conditions. Aphid colonies were exposed to two treatments (control and EBF and tested in two different environmental conditions (field and laboratory. As in previous experiments aphids produced higher proportion of winged morphs among their offspring when exposed to EBF in the laboratory but even under field conditions the proportion of winged offspring was higher after EBF application (6.84+/-0.98% compared to the hexane control (1.54+/-0.25%. In the field, the proportion of adult aphids found on the plant at the end of the experiment was lower in the EBF treatment (58.1+/-5.5% than in the control (66.9+/-4.6%, in contrast to the climate chamber test where the numbers of adult aphids found on the plant at the end of the experiment were, in both treatments, similar to the numbers put on the plant initially. Our results show that the role of EBF in aphid wing induction is also apparent under field conditions and they may indicate a potential cost of EBF emission. They also emphasize the importance of investigating the ecological role of induced defences under field conditions.

  9. Insulin-related peptide 5 is involved in regulating embryo development and biochemical composition in pea aphid with wing polyphenism

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    Shan-Shan eGuo

    2016-02-01

    Full Text Available In aphids there is a fecundity-dispersal trade-off between wingless and winged morphs. Recent research on the molecular mechanism of wing morphs associated with dispersal reveals that insulin receptors in the insulin signaling (IS pathway regulate alteration of wing morphs in planthoppers. However, little is known about whether genes in the IS pathway are involved in developmental regulation in aphid nymphs with different wing morphs. In this study, we show that expression of the insulin-related peptide 5 gene (Apirp5 affects biochemical composition and embryo development of wingless pea aphids, Acyrthosiphon pisum. After comparing expression levels of major genes in the IS pathway between third instar winged and wingless nymphs, we found that Apirp5 showed higher expression in head and thorax of the wingless nymphs than in the winged nymphs. Although microinjection treatment affects physical performance in aphids, nymphs with RNA interference of Apirp5 had less weight, smaller embryo size and higher carbohydrate and protein contents compared to control group. Comparison between winged and wingless nymphs showed a similar trend. These results indicate that Apirp5 is involved in embryo development and metabolic regulation in wing dimorphic pea aphid.

  10. New aeroelastic studies for a morphing wing

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    Ruxandra Mihaela BOTEZ*

    2012-06-01

    Full Text Available For this study, the upper surface of a rectangular finite aspect ratio wing, with a laminar airfoil cross-section, was made of a carbon-Kevlar composite material flexible skin. This flexible skin was morphed by use of Shape Memory Alloy actuators for 35 test cases characterized by combinations of Mach numbers, Reynolds numbers and angles of attack. The Mach numbers varied from 0.2 to 0.3 and the angles of attack ranged between -1° and 2°. The optimized airfoils were determined by use of the CFD XFoil code. The purpose of this aeroelastic study was to determine the flutter conditions to be avoided during wind tunnel tests. These studies show that aeroelastic instabilities for the morphing configurations considered appeared at Mach number 0.55, which was higher than the wind tunnel Mach number limit speed of 0.3. The wind tunnel tests could thus be performed safely in the 6’×9’ wind tunnel at the Institute for Aerospace Research at the National Research Council Canada (IAR/NRC, where the new aeroelastic studies, applied on morphing wings, were validated.

  11. Aeroelasticity of morphing wings using neural networks

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    Natarajan, Anand

    In this dissertation, neural networks are designed to effectively model static non-linear aeroelastic problems in adaptive structures and linear dynamic aeroelastic systems with time varying stiffness. The use of adaptive materials in aircraft wings allows for the change of the contour or the configuration of a wing (morphing) in flight. The use of smart materials, to accomplish these deformations, can imply that the stiffness of the wing with a morphing contour changes as the contour changes. For a rapidly oscillating body in a fluid field, continuously adapting structural parameters may render the wing to behave as a time variant system. Even the internal spars/ribs of the aircraft wing which define the wing stiffness can be made adaptive, that is, their stiffness can be made to vary with time. The immediate effect on the structural dynamics of the wing, is that, the wing motion is governed by a differential equation with time varying coefficients. The study of this concept of a time varying torsional stiffness, made possible by the use of active materials and adaptive spars, in the dynamic aeroelastic behavior of an adaptable airfoil is performed here. Another type of aeroelastic problem of an adaptive structure that is investigated here, is the shape control of an adaptive bump situated on the leading edge of an airfoil. Such a bump is useful in achieving flow separation control for lateral directional maneuverability of the aircraft. Since actuators are being used to create this bump on the wing surface, the energy required to do so needs to be minimized. The adverse pressure drag as a result of this bump needs to be controlled so that the loss in lift over the wing is made minimal. The design of such a "spoiler bump" on the surface of the airfoil is an optimization problem of maximizing pressure drag due to flow separation while minimizing the loss in lift and energy required to deform the bump. One neural network is trained using the CFD code FLUENT to

  12. Bacterial symbionts, Buchnera, and starvation on wing dimorphism in English grain aphid, Sitobion avenae (F. (Homoptera: Aphididae

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    Fangmei eZhang

    2015-05-01

    Full Text Available Wing dimorphism in aphids can be affected by multiple cues, including both biotic (nutrition, crowding, interspecific interactions, the presence of natural enemies, maternal and transgenerational effects, and alarm pheromone and abiotic factors (temperature, humidity, and photoperiod. The majority of the phloem-feeding aphids carry Buchnera, an obligate symbiotic proteobacteria. Buchnera has a highly reduced genome size, but encode key enzymes in the tryptophan biosynthetic pathway and is crucial for nutritional balance, development and reproduction in aphids. In this study, we investigated the impact of two nutritional-based biotic factors, symbionts and starvation, on the wing dimorphism in the English grain aphid, Sitobion avenae, a devastating insect pest of cereal crops (e.g., wheat worldwide. Elimination of Buchnera using the antibiotic rifampicin significantly reduced the formation of winged morphs, body mass and fecundity in S. avenae. Furthermore, the absence of this primary endosymbiont may disrupt the nutrient acquisition in aphids and alter transgenerational phenotypic expression. Similarly, both survival rate and the formation of winged morphs were substantially reduced after neonatal (< 24h old offspring were starved for a period of time. The combined results shed light on the impact of two nutritional-based biotic factors on the phenotypic plasticity in aphids. A better understanding of the wing dimorphism in aphids will provide the theoretical basis for the prediction and integrated management of these phloem-feeding insect pests.

  13. Energy-based Aeroelastic Analysis and Optimisation of Morphing Wings

    NARCIS (Netherlands)

    De Breuker, R.

    2011-01-01

    Morphing aircraft can change their shape radically when confronted with a variety of conflicting flight conditions throughout their mission. For instance the F-14 Tomcat fighter aircraft, known from the movie Top Gun, was able to sweep its wings from a straight wing configuration to a highly swept

  14. Application of SMP composite in designing a morphing wing

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    Yu, Kai; Yin, Weilong; Liu, Yanju; Leng, Jinsong

    2008-11-01

    A new concept of a morphing wing based on shape memory polymer (SMP) and its reinforced composite is proposed in this paper. SMP used in this study is a thermoset styrene-based resin in contrast to normal thermoplastic SMP. In our design, the wing winded on the airframe can be deployed during heating, which provides main lift for a morphing aircraft to realize stable flight. Aerodynamic characteristics of the deployed morphing wing are calculated by using CFD software. The static deformation of the wing under the air loads is also analyzed by using the finite element method. The results show that the used SMP material can provide enough strength and stiffness for the application.

  15. Folding in and out: passive morphing in flapping wings.

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    Stowers, Amanda K; Lentink, David

    2015-03-25

    We present a new mechanism for passive wing morphing of flapping wings inspired by bat and bird wing morphology. The mechanism consists of an unactuated hand wing connected to the arm wing with a wrist joint. Flapping motion generates centrifugal accelerations in the hand wing, forcing it to unfold passively. Using a robotic model in hover, we made kinematic measurements of unfolding kinematics as functions of the non-dimensional wingspan fold ratio (2-2.5) and flapping frequency (5-17 Hz) using stereo high-speed cameras. We find that the wings unfold passively within one to two flaps and remain unfolded with only small amplitude oscillations. To better understand the passive dynamics, we constructed a computer model of the unfolding process based on rigid body dynamics, contact models, and aerodynamic correlations. This model predicts the measured passive unfolding within about one flap and shows that unfolding is driven by centrifugal acceleration induced by flapping. The simulations also predict that relative unfolding time only weakly depends on flapping frequency and can be reduced to less than half a wingbeat by increasing flapping amplitude. Subsequent dimensional analysis shows that the time required to unfold passively is of the same order of magnitude as the flapping period. This suggests that centrifugal acceleration can drive passive unfolding within approximately one wingbeat in small and large wings. Finally, we show experimentally that passive unfolding wings can withstand impact with a branch, by first folding and then unfolding passively. This mechanism enables flapping robots to squeeze through clutter without sophisticated control. Passive unfolding also provides a new avenue in morphing wing design that makes future flapping morphing wings possibly more energy efficient and light-weight. Simultaneously these results point to possible inertia driven, and therefore metabolically efficient, control strategies in bats and birds to morph or recover

  16. The interplay between density- and trait-mediated effects in predator-prey interactions: a case study in aphid wing polymorphism.

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    Kunert, Grit; Weisser, Wolfgang W

    2003-04-01

    Natural enemies not only influence prey density but they can also cause the modification of traits in their victims. While such non-lethal effects can be very important for the dynamic and structure of prey populations, little is known about their interaction with the density-mediated effects of natural enemies. We investigated the relationship between predation rate, prey density and trait modification in two aphid-aphid predator interactions. Pea aphids (Acyrthosiphon pisum, Harris) have been shown to produce winged dispersal morphs in response to the presence of ladybirds or parasitoid natural enemies. This trait modification influences the ability of aphids to disperse and to colonise new habitats, and hence has a bearing on the population dynamics of the prey. In two experiments we examined wing induction in pea aphids as a function of the rate of predation when hoverfly larvae (Episyrphus balteatus) and lacewing larvae (Chrysoperla carnea) were allowed to forage in pea aphid colonies. Both hoverfly and lacewing larvae caused a significant increase in the percentage of winged morphs among offspring compared to control treatments, emphasising that wing induction in the presence of natural enemies is a general response in pea aphids. The percentage of winged offspring was, however, dependent on the rate of predation, with a small effect of predation on aphid wing induction at very high and very low predation rates, and a strong response of aphids at medium predation rates. Aphid wing induction was influenced by the interplay between predation rate and the resultant prey density. Our results suggests that density-mediated and trait-mediated effects of natural enemies are closely connected to each other and jointly determine the effect of natural enemies on prey population dynamics.

  17. Optimization of aerodynamic efficiency for twist morphing MAV wing

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    N.I. Ismail

    2014-06-01

    Full Text Available Twist morphing (TM is a practical control technique in micro air vehicle (MAV flight. However, TM wing has a lower aerodynamic efficiency (CL/CD compared to membrane and rigid wing. This is due to massive drag penalty created on TM wing, which had overwhelmed the successive increase in its lift generation. Therefore, further CL/CDmax optimization on TM wing is needed to obtain the optimal condition for the morphing wing configuration. In this paper, two-way fluid–structure interaction (FSI simulation and wind tunnel testing method are used to solve and study the basic wing aerodynamic performance over (non-optimal TM, membrane and rigid wings. Then, a multifidelity data metamodel based design optimization (MBDO process is adopted based on the Ansys-DesignXplorer frameworks. In the adaptive MBDO process, Kriging metamodel is used to construct the final multifidelity CL/CD responses by utilizing 23 multi-fidelity sample points from the FSI simulation and experimental data. The optimization results show that the optimal TM wing configuration is able to produce better CL/CDmax magnitude by at least 2% than the non-optimal TM wings. The flow structure formation reveals that low TV strength on the optimal TM wing induces low CD generation which in turn improves its overall CL/CDmax performance.

  18. Composite corrugated structures for morphing wing skin applications

    International Nuclear Information System (INIS)

    Thill, C; Etches, J A; Bond, I P; Potter, K D; Weaver, P M

    2010-01-01

    Composite corrugated structures are known for their anisotropic properties. They exhibit relatively high stiffness parallel (longitudinal) to the corrugation direction and are relatively compliant in the direction perpendicular (transverse) to the corrugation. Thus, they offer a potential solution for morphing skin panels (MSPs) in the trailing edge region of a wing as a morphing control surface. In this paper, an overview of the work carried out by the present authors over the last few years on corrugated structures for morphing skin applications is first given. The second part of the paper presents recent work on the application of corrugated sandwich structures. Panels made from multiple unit cells of corrugated sandwich structures are used as MSPs in the trailing edge region of a scaled morphing aerofoil section. The aerofoil section features an internal actuation mechanism that allows chordwise length and camber change of the trailing edge region (aft 35% chord). Wind tunnel testing was carried out to demonstrate the MSP concept but also to explore its limitations. Suggestions for improvements arising from this study were deduced, one of which includes an investigation of a segmented skin. The overall results of this study show that the MSP concept exploiting corrugated sandwich structures offers a potential solution for local morphing wing skins for low speed and small air vehicles

  19. Demonstration of an in situ morphing hyperelliptical cambered span wing mechanism

    International Nuclear Information System (INIS)

    Manzo, Justin; Garcia, Ephrahim

    2010-01-01

    Research on efficient shore bird morphology inspired the hyperelliptical cambered span (HECS) wing, a crescent-shaped, aft-swept wing with vertically oriented wingtips. The wing reduces vorticity-induced circulation loss and outperforms an elliptical baseline when planar. Designed initially as a rigid wing, the HECS wing makes use of morphing to transition from a planar to a furled configuration, similar to that of a continuously curved winglet, in flight. A morphing wing concept mechanism is presented, employing shape memory alloy actuators to create a discretized curvature approximation. The aerodynamics for continuous wing shapes is validated quasi-statically through wind tunnel testing, showing enhanced planar HECS wing lift-to-drag performance over an elliptical wing, with the furled HECS wing showing minimal enhancements beyond this point. Wind tunnel tests of the active morphing wing prove the mechanism capable of overcoming realistic loading, while further testing may be required to establish aerodynamic merits of the HECS wing morphing maneuver

  20. Quantifying the dynamic wing morphing of hovering hummingbird.

    Science.gov (United States)

    Maeda, Masateru; Nakata, Toshiyuki; Kitamura, Ikuo; Tanaka, Hiroto; Liu, Hao

    2017-09-01

    Animal wings are lightweight and flexible; hence, during flapping flight their shapes change. It has been known that such dynamic wing morphing reduces aerodynamic cost in insects, but the consequences in vertebrate flyers, particularly birds, are not well understood. We have developed a method to reconstruct a three-dimensional wing model of a bird from the wing outline and the feather shafts (rachides). The morphological and kinematic parameters can be obtained using the wing model, and the numerical or mechanical simulations may also be carried out. To test the effectiveness of the method, we recorded the hovering flight of a hummingbird ( Amazilia amazilia ) using high-speed cameras and reconstructed the right wing. The wing shape varied substantially within a stroke cycle. Specifically, the maximum and minimum wing areas differed by 18%, presumably due to feather sliding; the wing was bent near the wrist joint, towards the upward direction and opposite to the stroke direction; positive upward camber and the 'washout' twist (monotonic decrease in the angle of incidence from the proximal to distal wing) were observed during both half-strokes; the spanwise distribution of the twist was uniform during downstroke, but an abrupt increase near the wrist joint was found during upstroke.

  1. Analysis and optimization of a camber morphing wing model

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    Bing Li

    2016-09-01

    Full Text Available This article proposes a camber morphing wing model that can continuously change its camber. A mathematical model is proposed and a kinematic simulation is performed to verify the wing’s ability to change camber. An aerodynamic model is used to test its aerodynamic characteristics. Some important aerodynamic analyses are performed. A comparative analysis is conducted to explore the relationships between aerodynamic parameters, the rotation angle of the trailing edge, and the angle of attack. An improved artificial fish swarm optimization algorithm is proposed, referred to as the weighted adaptive artificial fish-swarm with embedded Hooke–Jeeves search method. Some comparison tests are used to test the performance of the improved optimization algorithm. Finally, the proposed optimization algorithm is used to optimize the proposed camber morphing wing model.

  2. Development and Testing of an Unconventional Morphing Wing Concept with Variable Chord and Camber

    NARCIS (Netherlands)

    Keidel, D.H.K.; Sodja, J.; Werter, N.P.M.; De Breuker, R.; Ermanni, P.; Monajjemi, M.; Liang, W.

    2015-01-01

    Driven by the need to improve the performance and energy-efficiency of aircraft, current research in the field of morphing wings is growing in significance. The most recently developed concepts typically adjust only one characteristic of the wing. Within this paper a new concept for morphing wings

  3. The analysis of the flying wing in morphing concept

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    Ionică CÎRCIU

    2013-06-01

    Full Text Available The combination between the flying wing morphing concept and the use of modern command and control system offers exponential advantages having a leverage effect in the economy and research. The flying wing architecture has the advantage of low cost against efficiency, the morphing of this concept defining the new characteristic frontiers and aerodynamic performances which derive immediately. On designing an unmanned aerial vehicle for a various range of missions, its lifting surface needs to display optimal geometrical features, so that the UAV may maintain the induced drag and the moment coefficient at reasonable levels. The command and control of the lifting surfaces in morphing concept offer characteristics and in-flight performances at a superior level. The limits of the system depend on the reliability of the execution elements and the grade of accuracy for the control laws which are implemented in the calculation module. The paper aims at presenting an analysis regarding the robotic air systems of flying wing type through the aerodynamic analysis and with the help of specific software instruments. The performances and flight qualities depend directly on the geometry of the lifting surface of the aerial vehicle.

  4. Aerodynamics and Ecomorphology of Flexible Feathers and Morphing Bird Wings

    Science.gov (United States)

    Klaassen van Oorschot, Brett

    Birds are talented fliers capable of vertical take-off and landing, navigating turbulent air, and flying thousands of miles without rest. How is this possible? What allows birds to exploit the aerial environment with such ease? In part, it may be because bird wings are unlike any engineered wing. They are flexible, strong, lightweight, and dynamically capable of changes in shape on a nearly instantaneous basis (Rayner, 1988; Tobalske, 2007). Moreover, much of this change is passive, modulated only by changes in airflow angle and velocity. Birds actively morph their wings and their feathers morph passively in response to airflow to meet aerodynamic demands. Wings are highly adapted to myriad aeroecological factors and aerodynamic conditions (e.g. Lockwood et al., 1998; Bowlin and Winkler, 2004). This dissertation contains the results of my research on the complexities of morphing avian wings and feathers. I chose to study three related-but-discrete aspects of the avian wing: 1) the aerodynamics of morphing wings during take-off and gliding flight, 2) the presence and significance of wing tip slots across the avian clade, and 3) the aerodynamic role of the emarginate primary feathers that form these wing tip slots. These experiments ask fundamental questions that have intrigued me since childhood: Why do birds have different wing shapes? And why do some birds have slotted wing tips? It's fair to say that you will not find definitive answers here--rather, you will find the methodical, incremental addition of new hypotheses and empirical evidence which will serve future researchers in their own pursuits of these questions. The first chapter explores active wing morphing in two disparate aerodynamic regimes: low-advance ratio flapping (such as during takeoff) and high-advance ratio gliding. This chapter was published in the Journal of Experimental Biology (Klaassen van Oorschot et al., 2016) with the help of an undergraduate researcher, Emily Mistick. We found that wing

  5. Topology Synthesis of Distributed Actuation Systems for Morphing Wing Structures (Postprint)

    National Research Council Canada - National Science Library

    Inoyam, Daisaku; Sanders, Brian P; Joo, James J

    2007-01-01

    .... For demonstration purposes, the in-plane morphing wing model is presented. Topology optimization is performed on a semiground structure with design variables that control the system configuration...

  6. Spanwise morphing trailing edge on a finite wing

    Science.gov (United States)

    Pankonien, Alexander M.; Inman, Daniel J.

    2015-04-01

    Unmanned Aerial Vehicles are prime targets for morphing implementation as they must adapt to large changes in flight conditions associated with locally varying wind or large changes in mass associated with payload delivery. The Spanwise Morphing Trailing Edge concept locally varies the trailing edge camber of a wing or control surface, functioning as a modular replacement for conventional ailerons without altering the spar box. Utilizing alternating active sections of Macro Fiber Composites (MFCs) driving internal compliant mechanisms and inactive sections of elastomeric honeycombs, the SMTE concept eliminates geometric discontinuities associated with shape change, increasing aerodynamic performance. Previous work investigated a representative section of the SMTE concept and investigated the effect of various skin designs on actuation authority. The current work experimentally evaluates the aerodynamic gains for the SMTE concept for a representative finite wing as compared with a conventional, articulated wing. The comparative performance for both wings is evaluated by measuring the drag penalty associated with achieving a design lift coefficient from an off-design angle of attack. To reduce experimental complexity, optimal control configurations are predicted with lifting line theory and experimentally measured control derivatives. Evaluated over a range of off-design flight conditions, this metric captures the comparative capability of both concepts to adapt or "morph" to changes in flight conditions. Even with this simplistic model, the SMTE concept is shown to reduce the drag penalty due to adaptation up to 20% at off-design conditions, justifying the increase in mass and complexity and motivating concepts capable of larger displacement ranges, higher fidelity modelling, and condition-sensing control.

  7. Biomechanics of smart wings in a bat robot: morphing wings using SMA actuators

    International Nuclear Information System (INIS)

    Colorado, J; Barrientos, A; Rossi, C; Breuer, K S

    2012-01-01

    This paper presents the design of a bat-like micro aerial vehicle with actuated morphing wings. NiTi shape memory alloys (SMAs) acting as artificial biceps and triceps muscles are used for mimicking the morphing wing mechanism of the bat flight apparatus. Our objective is twofold. Firstly, we have implemented a control architecture that allows an accurate and fast SMA actuation. This control makes use of the electrical resistance measurements of SMAs to adjust morphing wing motions. Secondly, the feasibility of using SMA actuation technology is evaluated for the application at hand. To this purpose, experiments are conducted to analyze the control performance in terms of nominal and overloaded operation modes of the SMAs. This analysis includes: (i) inertial forces regarding the stretchable wing membrane and aerodynamic loads, and (ii) uncertainties due to impact of airflow conditions over the resistance–motion relationship of SMAs. With the proposed control, morphing actuation speed can be increased up to 2.5 Hz, being sufficient to generate lift forces at a cruising speed of 5 m s −1 . (paper)

  8. Biomechanics of smart wings in a bat robot: morphing wings using SMA actuators.

    Science.gov (United States)

    Colorado, J; Barrientos, A; Rossi, C; Bahlman, J W; Breuer, K S

    2012-09-01

    This paper presents the design of a bat-like micro aerial vehicle with actuated morphing wings. NiTi shape memory alloys (SMAs) acting as artificial biceps and triceps muscles are used for mimicking the morphing wing mechanism of the bat flight apparatus. Our objective is twofold. Firstly, we have implemented a control architecture that allows an accurate and fast SMA actuation. This control makes use of the electrical resistance measurements of SMAs to adjust morphing wing motions. Secondly, the feasibility of using SMA actuation technology is evaluated for the application at hand. To this purpose, experiments are conducted to analyze the control performance in terms of nominal and overloaded operation modes of the SMAs. This analysis includes: (i) inertial forces regarding the stretchable wing membrane and aerodynamic loads, and (ii) uncertainties due to impact of airflow conditions over the resistance-motion relationship of SMAs. With the proposed control, morphing actuation speed can be increased up to 2.5 Hz, being sufficient to generate lift forces at a cruising speed of 5 m s(-1).

  9. Piezoelectric energy harvesting from morphing wing motions for micro air vehicles

    KAUST Repository

    Abdelkefi, Abdessattar

    2013-09-10

    Wing flapping and morphing can be very beneficial to managing the weight of micro air vehicles through coupling the aerodynamic forces with stability and control. In this letter, harvesting energy from the wing morphing is studied to power cameras, sensors, or communication devices of micro air vehicles and to aid in the management of their power. The aerodynamic loads on flapping wings are simulated using a three-dimensional unsteady vortex lattice method. Active wing shape morphing is considered to enhance the performance of the flapping motion. A gradient-based optimization algorithm is used to pinpoint the optimal kinematics maximizing the propellent efficiency. To benefit from the wing deformation, we place piezoelectric layers near the wing roots. Gauss law is used to estimate the electrical harvested power. We demonstrate that enough power can be generated to operate a camera. Numerical analysis shows the feasibility of exploiting wing morphing to harvest energy and improving the design and performance of micro air vehicles.

  10. Dynamic Model and Analysis of Asymmetric Telescopic Wing for Morphing Aircraft

    Directory of Open Access Journals (Sweden)

    Chen Lili

    2016-01-01

    Full Text Available Morphing aircraft has been the research hot topics of new concept aircrafts in aerospace engineering. Telescopic wing is an important morphing technology for morphing aircraft. This paper describes the dynamic equations and kinematic equations based on theorem of momentum and theorem of moment of momentum, which are available for all morphing aircrafts. Meanwhile,as simplified , dynamic equations for rectangular telescopic wing are presented. In order to avoid the complexity using aileron to generate rolling moment , an new idea that asymmetry of wings can generate roll moment is introduced. Finally, roll performance comparison of asymmetric wing and aileron deflection shows that asymmetric telescopic wing can provide the required roll control moment as aileron, and in some cases, telescopic wing has the superior roll performance.

  11. Morphing wing system integration with wind tunnel testing =

    Science.gov (United States)

    Guezguez, Mohamed Sadok

    Preserving the environment is a major challenge for today's aviation industry. Within this context, the CRIAQ MDO 505 project started, where a multidisciplinary approach was used to improve aircraft fuel efficiency. This international project took place between several Canadian and Italian teams. Industrial teams are Bombardier Aerospace, Thales Canada and Alenia Aermacchi. The academic partners are from Ecole de Technologie Superieure, Ecole Polytechnique de Montreal and Naples University. Teams from 'CIRA' and IAR-NRC research institutes had, also, contributed on this project. The main objective of this project is to improve the aerodynamic performance of a morphing wing prototype by reducing the drag. This drag reduction is achieved by delaying the flow transition (from laminar to turbulent) by performing shape optimization of the flexible upper skin according to different flight conditions. Four linear axes, each one actuated by a 'BLDC' motor, are used to morph the skin. The skin displacements are calculated by 'CFD' numerical simulation based on flow parameters which are Mach number, the angle of attack and aileron's angle of deflection. The wing is also equipped with 32 pressure sensors to experimentally detect the transition during aerodynamic testing in the subsonic wind tunnel at the IAR-NRC in Ottawa. The first part of the work is dedicated to establishing the necessary fieldbus communications between the control system and the wing. The 'CANopen' protocol is implemented to ensure real time communication between the 'BLDC' drives and the real-time controller. The MODBUS TCP protocol is used to control the aileron drive. The second part consists of implementing the skin control position loop based on the LVDTs feedback, as well as developing an automated calibration procedure for skin displacement values. Two 'sets' of wind tunnel tests were carried out to, experimentally, investigate the morphing wing controller effect; these tests also offered the

  12. Morphing Wing: Experimental Boundary Layer Transition Determination and Wing Vibrations Measurements and Analysis =

    Science.gov (United States)

    Tondji Chendjou, Yvan Wilfried

    This Master's thesis is written within the framework of the multidisciplinary international research project CRIAQ MDO-505. This global project consists of the design, manufacture and testing of a morphing wing box capable of changing the shape of the flexible upper skin of a wing using an actuator system installed inside the wing. This changing of the shape generates a delay in the occurrence of the laminar to turbulent transition area, which results in an improvement of the aerodynamic performances of the morphed wing. This thesis is focused on the technologies used to gather the pressure data during the wind tunnel tests, as well as on the post processing methodologies used to characterize the wing airflow. The vibration measurements of the wing and their real-time graphical representation are also presented. The vibration data acquisition system is detailed, and the vibration data analysis confirms the predictions of the flutter analysis performed on the wing prior to wind tunnel testing at the IAR-NRC. The pressure data was collected using 32 highly-sensitive piezoelectric sensors for sensing the pressure fluctuations up to 10 KHz. These sensors were installed along two wing chords, and were further connected to a National Instrument PXI real-time acquisition system. The acquired pressure data was high-pass filtered, analyzed and visualized using Fast Fourier Transform (FFT) and Standard Deviation (SD) approaches to quantify the pressure fluctuations in the wing airflow, as these allow the detection of the laminar to turbulent transition area. Around 30% of the cases tested in the IAR-NRC wind tunnel were optimized for drag reduction by the morphing wing procedure. The obtained pressure measurements results were compared with results obtained by infrared thermography visualization, and were used to validate the numerical simulations. Two analog accelerometers able to sense dynamic accelerations up to +/-16g were installed in both the wing and the aileron boxes

  13. Morphing Wing Weight Predictors and Their Application in a Template-Based Morphing Aircraft Sizing Environment II. Part 2; Morphing Aircraft Sizing via Multi-level Optimization

    Science.gov (United States)

    Skillen, Michael D.; Crossley, William A.

    2008-01-01

    This report presents an approach for sizing of a morphing aircraft based upon a multi-level design optimization approach. For this effort, a morphing wing is one whose planform can make significant shape changes in flight - increasing wing area by 50% or more from the lowest possible area, changing sweep 30 or more, and/or increasing aspect ratio by as much as 200% from the lowest possible value. The top-level optimization problem seeks to minimize the gross weight of the aircraft by determining a set of "baseline" variables - these are common aircraft sizing variables, along with a set of "morphing limit" variables - these describe the maximum shape change for a particular morphing strategy. The sub-level optimization problems represent each segment in the morphing aircraft's design mission; here, each sub-level optimizer minimizes fuel consumed during each mission segment by changing the wing planform within the bounds set by the baseline and morphing limit variables from the top-level problem.

  14. Performance of a non-tapered 3D morphing wing with integrated compliant ribs

    International Nuclear Information System (INIS)

    Previtali, F; Ermanni, P

    2012-01-01

    Morphing wings have a high potential for improving the performance and reducing the fuel consumption of modern aircraft. Thanks to its simplicity, the compliant belt-rib concept is regarded by the authors as a promising solution. Using the compliant rib designed by Hasse and Campanile as a starting point, a compliant morphing wing made of composite materials is designed. Innovative methods for optimal placing of the actuation and for the quantification of the morphing are used. The performance of the compliant morphing wing in terms of three-dimensional (3D) structural behaviour and aerodynamic properties, both two- and three-dimensional, is presented and discussed. The fundamental importance of considering 3D coupling effects in the determination of the performance of morphing aerofoils is shown. (paper)

  15. Performance Comparison between Optimised Camber and Span for a Morphing Wing

    Directory of Open Access Journals (Sweden)

    Christopher Simon Beaverstock

    2015-09-01

    Full Text Available Morphing technology offers a strategy to modify the wing geometry, and the wing planform and cross-sectional parameters can be optimised to the flight conditions. This paper presents an investigation into the effect of span and camber morphing on the mission performance of a 25-kg UAV, with a straight, rectangular, unswept wing. The wing is optimised over two velocities for various fixed wing and morphing wing strategies, where the objective is to maximise aerodynamic efficiency or range. The investigation analyses the effect of the low and high speed velocity selected, the weighting of the low and high velocity on the computation of the mission parameter, the maximum allowable span retraction and the weight penalty on the mission performance. Models that represent the adaptive aspect ratio (AdAR span morphing concept and the fish bone active camber (FishBAC camber morphing concept are used to investigate the effect on the wing parameters. The results indicate that generally morphing for both span and camber, the aerodynamic efficiency is maximised for a 30%–70% to 40%–60% weighting between the low and high speed flight conditions, respectively. The span morphing strategy with optimised fixed camber at the root can deliver up to 25% improvement in the aerodynamic efficiency over a fixed camber and span, for an allowable 50% retraction with a velocity range of 50–115 kph. Reducing the allowable retraction to 25% reduces the improvement to 8%–10% for a 50%–50% mission weighting. Camber morphing offers a maximum of 4.5% improvement approximately for a velocity range of 50–90 kph. Improvements in the efficiency achieved through camber morphing are more sensitive to the velocity range in the mission, generally decreasing rapidly by reducing or increasing the velocity range, where span morphing appears more robust for an increase in velocity range beyond the optimum. However, where span morphing requires considerable modification to the

  16. A Neural Network Controller New Methodology for the ATR-42 Morphing Wing Actuation

    OpenAIRE

    Abdallah Ben MOSBAH; Ruxandra Mihaela BOTEZ; Thien My DAO; Mohamed Sadok GUEZGUEZ; Mahdi ZAAG

    2016-01-01

    A morphing wing model is used to improve aircraft performance. To obtain the desired airfoils, electrical actuators are used, which are installed inside of the wing to morph its upper surface in order to obtain its desired shape. In order to achieve this objective, a robust position controller is needed. In this research, a design and test validation of a controller based on neural networks is presented. This controller was composed by a position controller and a current controller to manage ...

  17. Morphing Wings: A Study Using High-Fidelity Aerodynamic Shape Optimization

    Science.gov (United States)

    Curiale, Nathanael J.

    With the aviation industry under pressure to reduce fuel consumption, morphing wings have the capacity to improve aircraft performance, thereby making a significant contribution to reversing climate change. Through high-fidelity aerodynamic shape optimization, various forms of morphing wings are assessed for a hypothetical regional-class aircraft. The framework used solves the Reynolds-averaged Navier-Stokes equations and utilizes a gradient-based optimization algorithm. Baseline geometries are developed through multipoint optimization, where the average drag coefficient is minimized over a range of flight conditions with additional dive constraints. Morphing optimizations are then performed, beginning with these baseline shapes. Five distinct types of morphing are investigated and compared. Overall, a theoretical fully adaptable wing produces roughly a 2% improvement in average performance, whereas trailing-edge morphing with a 27-point multipoint baseline results in just over a 1% improvement in average performance. Trailing-edge morphing proves to be more beneficial than leading-edge morphing, upper-surface morphing, and a conventional flap.

  18. Morphing Wing-Tip Open Loop Controller and its Validation During Wind Tunnel Tests at the IAR-NRC

    Directory of Open Access Journals (Sweden)

    Mohamed Sadok GUEZGUEZ

    2016-09-01

    Full Text Available In this project, a wing tip of a real aircraft was designed and manufactured. This wing tip was composed of a wing and an aileron. The wing was equipped with a composite skin on its upper surface. This skin changed its shape (morphed by use of 4 electrical in-house developed actuators and 32 pressure sensors. These pressure sensors measure the pressures, and further the loads on the wing upper surface. Thus, the upper surface of the wing was morphed using these actuators with the aim to improve the aerodynamic performances of the wing-tip. Two types of ailerons were designed and manufactured: one aileron is rigid (non-morphed and one morphing aileron. This morphing aileron can change its shape also for the aerodynamic performances improvement. The morphing wing-tip internal structure is designed and manufactured, and is presented firstly in the paper. Then, the modern communication and control hardware are presented for the entire morphing wing tip equipped with actuators and sensors having the aim to morph the wing. The calibration procedure of the wing tip is further presented, followed by the open loop controller results obtained during wind tunnel tests. Various methodologies of open loop control are presented in this paper, and results obtained were obtained and validated experimentally through wind tunnel tests.

  19. A Conceptual Development of a Shape Memory Alloy Actuated Variable Camber Morphing Wing

    NARCIS (Netherlands)

    Ferreira, J.P.; De Breuker, R.

    2016-01-01

    This study describes the development of a morphing wing concept for a Portuguese Air Force Unmanned Air Vehicle (UAV), the UAS-30. Nowadays, optimized fuel efficiency is a primary requirement in the aerospace industry, and it can be significantly improved by designing adaptive wings which can change

  20. Analysis of the small flying wings performances in the morphing concept

    Directory of Open Access Journals (Sweden)

    Prisacariu Vasile

    2017-01-01

    Full Text Available Using of the flying wing (the UAVs category in various fields (civilian and military determine interests sustained of the aerodynamic and trajectory optimizations. The article presents analysis of wing flying performance (in morphing concept by studying optimizing the maneuvers control and wind tunnel tests.

  1. Flutter suppression and stability analysis for a variable-span wing via morphing technology

    Science.gov (United States)

    Li, Wencheng; Jin, Dongping

    2018-01-01

    A morphing wing can enhance aerodynamic characteristics and control authority as an alternative to using ailerons. To use morphing technology for flutter suppression, the dynamical behavior and stability of a variable-span wing subjected to the supersonic aerodynamic loads are investigated numerically in this paper. An axially moving cantilever plate is employed to model the variable-span wing, in which the governing equations of motion are established via the Kane method and piston theory. A morphing strategy based on axially moving rates is proposed to suppress the flutter that occurs beyond the critical span length, and the flutter stability is verified by Floquet theory. Furthermore, the transient stability during the morphing motion is analyzed and the upper bound of the morphing rate is obtained. The simulation results indicate that the proposed morphing law, which is varying periodically with a proper amplitude, could accomplish the flutter suppression. Further, the upper bound of the morphing speed decreases rapidly once the span length is close to its critical span length.

  2. Bioinspired morphing wings for extended flight envelope and roll control of small drones

    OpenAIRE

    di Luca, Matteo; Mintchev, Stefano; Heitz, Grégoire Hilaire Marie; Noca, Flavio; Floreano, Dario

    2017-01-01

    Small-winged drones can face highly varied aerodynamic requirements, such as high manoeuvrability for flight among obstacles and high wind resistance for constant ground speed against strong headwinds that cannot all be optimally addressed by a single aerodynamic profile. Several bird species solve this problem by changing the shape of their wings to adapt to the different aerodynamic requirements. Here, we describe a novel morphing wing design composed of artificial feathers that can rapidly...

  3. Validation of morphing wing methodologies on an unmanned aerial system and a wind tunnel technology demonstrator

    Science.gov (United States)

    Gabor, Oliviu Sugar

    To increase the aerodynamic efficiency of aircraft, in order to reduce the fuel consumption, a novel morphing wing concept has been developed. It consists in replacing a part of the wing upper and lower surfaces with a flexible skin whose shape can be modified using an actuation system placed inside the wing structure. Numerical studies in two and three dimensions were performed in order to determine the gains the morphing system achieves for the case of an Unmanned Aerial System and for a morphing technology demonstrator based on the wing tip of a transport aircraft. To obtain the optimal wing skin shapes in function of the flight condition, different global optimization algorithms were implemented, such as the Genetic Algorithm and the Artificial Bee Colony Algorithm. To reduce calculation times, a hybrid method was created by coupling the population-based algorithm with a fast, gradient-based local search method. Validations were performed with commercial state-of-the-art optimization tools and demonstrated the efficiency of the proposed methods. For accurately determining the aerodynamic characteristics of the morphing wing, two new methods were developed, a nonlinear lifting line method and a nonlinear vortex lattice method. Both use strip analysis of the span-wise wing section to account for the airfoil shape modifications induced by the flexible skin, and can provide accurate results for the wing drag coefficient. The methods do not require the generation of a complex mesh around the wing and are suitable for coupling with optimization algorithms due to the computational time several orders of magnitude smaller than traditional three-dimensional Computational Fluid Dynamics methods. Two-dimensional and three-dimensional optimizations of the Unmanned Aerial System wing equipped with the morphing skin were performed, with the objective of improving its performances for an extended range of flight conditions. The chordwise positions of the internal actuators

  4. Bioinspired morphing wings for extended flight envelope and roll control of small drones.

    Science.gov (United States)

    Di Luca, M; Mintchev, S; Heitz, G; Noca, F; Floreano, D

    2017-02-06

    Small-winged drones can face highly varied aerodynamic requirements, such as high manoeuvrability for flight among obstacles and high wind resistance for constant ground speed against strong headwinds that cannot all be optimally addressed by a single aerodynamic profile. Several bird species solve this problem by changing the shape of their wings to adapt to the different aerodynamic requirements. Here, we describe a novel morphing wing design composed of artificial feathers that can rapidly modify its geometry to fulfil different aerodynamic requirements. We show that a fully deployed configuration enhances manoeuvrability while a folded configuration offers low drag at high speeds and is beneficial in strong headwinds. We also show that asymmetric folding of the wings can be used for roll control of the drone. The aerodynamic performance of the morphing wing is characterized in simulations, in wind tunnel measurements and validated in outdoor flights with a small drone.

  5. Bioinspired morphing wings for extended flight envelope and roll control of small drones

    Science.gov (United States)

    Heitz, G.; Noca, F.; Floreano, D.

    2017-01-01

    Small-winged drones can face highly varied aerodynamic requirements, such as high manoeuvrability for flight among obstacles and high wind resistance for constant ground speed against strong headwinds that cannot all be optimally addressed by a single aerodynamic profile. Several bird species solve this problem by changing the shape of their wings to adapt to the different aerodynamic requirements. Here, we describe a novel morphing wing design composed of artificial feathers that can rapidly modify its geometry to fulfil different aerodynamic requirements. We show that a fully deployed configuration enhances manoeuvrability while a folded configuration offers low drag at high speeds and is beneficial in strong headwinds. We also show that asymmetric folding of the wings can be used for roll control of the drone. The aerodynamic performance of the morphing wing is characterized in simulations, in wind tunnel measurements and validated in outdoor flights with a small drone. PMID:28163882

  6. Aerostructural optimization of a morphing wing for airborne wind energy applications

    Science.gov (United States)

    Fasel, U.; Keidel, D.; Molinari, G.; Ermanni, P.

    2017-09-01

    Airborne wind energy (AWE) vehicles maximize energy production by constantly operating at extreme wing loading, permitted by high flight speeds. Additionally, the wide range of wind speeds and the presence of flow inhomogeneities and gusts create a complex and demanding flight environment for AWE systems. Adaptation to different flow conditions is normally achieved by conventional wing control surfaces and, in case of ground generator-based systems, by varying the reel-out speed. These control degrees of freedom enable to remain within the operational envelope, but cause significant penalties in terms of energy output. A significantly greater adaptability is offered by shape-morphing wings, which have the potential to achieve optimal performance at different flight conditions by tailoring their airfoil shape and lift distribution at different levels along the wingspan. Hence, the application of compliant structures for AWE wings is very promising. Furthermore, active gust load alleviation can be achieved through morphing, which leads to a lower weight and an expanded flight envelope, thus increasing the power production of the AWE system. This work presents a procedure to concurrently optimize the aerodynamic shape, compliant structure, and composite layup of a morphing wing for AWE applications. The morphing concept is based on distributed compliance ribs, actuated by electromechanical linear actuators, guiding the deformation of the flexible—yet load-carrying—composite skin. The goal of the aerostructural optimization is formulated as a high-level requirement, namely to maximize the average annual power production per wing area of an AWE system by tailoring the shape of the wing, and to extend the flight envelope of the wing by actively alleviating gust loads. The results of the concurrent multidisciplinary optimization show a 50.7% increase of extracted power with respect to a sequentially optimized design, highlighting the benefits of morphing and the

  7. Digital Morphing Wing: Active Wing Shaping Concept Using Composite Lattice-Based Cellular Structures.

    Science.gov (United States)

    Jenett, Benjamin; Calisch, Sam; Cellucci, Daniel; Cramer, Nick; Gershenfeld, Neil; Swei, Sean; Cheung, Kenneth C

    2017-03-01

    We describe an approach for the discrete and reversible assembly of tunable and actively deformable structures using modular building block parts for robotic applications. The primary technical challenge addressed by this work is the use of this method to design and fabricate low density, highly compliant robotic structures with spatially tuned stiffness. This approach offers a number of potential advantages over more conventional methods for constructing compliant robots. The discrete assembly reduces manufacturing complexity, as relatively simple parts can be batch-produced and joined to make complex structures. Global mechanical properties can be tuned based on sub-part ordering and geometry, because local stiffness and density can be independently set to a wide range of values and varied spatially. The structure's intrinsic modularity can significantly simplify analysis and simulation. Simple analytical models for the behavior of each building block type can be calibrated with empirical testing and synthesized into a highly accurate and computationally efficient model of the full compliant system. As a case study, we describe a modular and reversibly assembled wing that performs continuous span-wise twist deformation. It exhibits high performance aerodynamic characteristics, is lightweight and simple to fabricate and repair. The wing is constructed from discrete lattice elements, wherein the geometric and mechanical attributes of the building blocks determine the global mechanical properties of the wing. We describe the mechanical design and structural performance of the digital morphing wing, including their relationship to wind tunnel tests that suggest the ability to increase roll efficiency compared to a conventional rigid aileron system. We focus here on describing the approach to design, modeling, and construction as a generalizable approach for robotics that require very lightweight, tunable, and actively deformable structures.

  8. Measurement of morphing wing deflection by a cross-coherence fiber optic interferometric technique

    Science.gov (United States)

    Tomić, Miloš C.; Djinović, Zoran V.; Scheerer, Michael; Petricevic, Slobodan J.

    2018-01-01

    A fiber-optic interferometric technique aimed at measuring the deflection of aircrafts’ morphing wings is presented. The wing deflection induces a strain in the sensing fiber optic coils that are firmly fixed onto the wing. A change of the phase angle of the light propagating through the fiber is measured by an ‘all-in-fiber’ Michelson interferometer based on a 3 × 3 fiber-optic coupler. Two light sources of different coherence lengths and wavelengths are simultaneously used to ensure a wide measurement range and high accuracy. A new technique for determination of the zero deflection point using the cross-correlation of the two interferograms is proposed. The experiments performed on a specimen made of a carbon-fiber-reinforced plastic honeycomb structure demonstrated a relative uncertainty morphing wing deflection.

  9. Feedback tracking control for dynamic morphing of piezocomposite actuated flexible wings

    Science.gov (United States)

    Wang, Xiaoming; Zhou, Wenya; Wu, Zhigang

    2018-03-01

    Aerodynamic properties of flexible wings can be improved via shape morphing using piezocomposite materials. Dynamic shape control of flexible wings is investigated in this study by considering the interactions between structural dynamics, unsteady aerodynamics and piezo-actuations. A novel antisymmetric angle-ply bimorph configuration of piezocomposite actuators is presented to realize coupled bending-torsional shape control. The active aeroelastic model is derived using finite element method and Theodorsen unsteady aerodynamic loads. A time-varying linear quadratic Gaussian (LQG) tracking control system is designed to enhance aerodynamic lift with pre-defined trajectories. Proof-of-concept simulations of static and dynamic shape control are presented for a scaled high-aspect-ratio wing model. Vibrations of the wing and fluctuations in aerodynamic forces are caused by using the static voltages directly in dynamic shape control. The lift response has tracked the trajectories well with favorable dynamic morphing performance via feedback tracking control.

  10. Proportional fuzzy feed-forward architecture control validation by wind tunnel tests of a morphing wing

    Directory of Open Access Journals (Sweden)

    Michel Joël Tchatchueng Kammegne

    2017-04-01

    Full Text Available In aircraft wing design, engineers aim to provide the best possible aerodynamic performance under cruise flight conditions in terms of lift-to-drag ratio. Conventional control surfaces such as flaps, ailerons, variable wing sweep and spoilers are used to trim the aircraft for other flight conditions. The appearance of the morphing wing concept launched a new challenge in the area of overall wing and aircraft performance improvement during different flight segments by locally altering the flow over the aircraft’s wings. This paper describes the development and application of a control system for an actuation mechanism integrated in a new morphing wing structure. The controlled actuation system includes four similar miniature electromechanical actuators disposed in two parallel actuation lines. The experimental model of the morphing wing is based on a full-scale portion of an aircraft wing, which is equipped with an aileron. The upper surface of the wing is a flexible one, being closed to the wing tip; the flexible skin is made of light composite materials. The four actuators are controlled in unison to change the flexible upper surface to improve the flow quality on the upper surface by delaying or advancing the transition point from laminar to turbulent regime. The actuators transform the torque into vertical forces. Their bases are fixed on the wing ribs and their top link arms are attached to supporting plates fixed onto the flexible skin with screws. The actuators push or pull the flexible skin using the necessary torque until the desired vertical displacement of each actuator is achieved. The four vertical displacements of the actuators, correlated with the new shape of the wing, are provided by a database obtained through a preliminary aerodynamic optimization for specific flight conditions. The control system is designed to control the positions of the actuators in real time in order to obtain and to maintain the desired shape of the

  11. How swifts control their glide performance with morphing wings

    NARCIS (Netherlands)

    Lentink, D.; Muller, U. K.; Stamhuis, E. J.; de Kat, R.; van Gestel, W.; Veldhuis, L. L. M.; Henningsson, P.; Hedenstrom, A.; Videler, J. J.

    2007-01-01

    Gliding birds continually change the shape and size of their wings(1-6), presumably to exploit the profound effect of wing morphology on aerodynamic performance(7-9). That birds should adjust wing sweep to suit glide speed has been predicted qualitatively by analytical glide models(2,10), which

  12. Aerodynamic consequences of wing morphing during emulated take-off and gliding in birds.

    Science.gov (United States)

    Klaassen van Oorschot, Brett; Mistick, Emily A; Tobalske, Bret W

    2016-10-01

    Birds morph their wings during a single wingbeat, across flight speeds and among flight modes. Such morphing may allow them to maximize aerodynamic performance, but this assumption remains largely untested. We tested the aerodynamic performance of swept and extended wing postures of 13 raptor species in three families (Accipitridae, Falconidae and Strigidae) using a propeller model to emulate mid-downstroke of flapping during take-off and a wind tunnel to emulate gliding. Based on previous research, we hypothesized that (1) during flapping, wing posture would not affect maximum ratios of vertical and horizontal force coefficients (C V :C H ), and that (2) extended wings would have higher maximum C V :C H when gliding. Contrary to each hypothesis, during flapping, extended wings had, on average, 31% higher maximum C V :C H ratios and 23% higher C V than swept wings across all biologically relevant attack angles (α), and, during gliding, maximum C V :C H ratios were similar for the two postures. Swept wings had 11% higher C V than extended wings in gliding flight, suggesting flow conditions around these flexed raptor wings may be different from those in previous studies of swifts (Apodidae). Phylogenetic affiliation was a poor predictor of wing performance, due in part to high intrafamilial variation. Mass was only significantly correlated with extended wing performance during gliding. We conclude that wing shape has a greater effect on force per unit wing area during flapping at low advance ratio, such as take-off, than during gliding. © 2016. Published by The Company of Biologists Ltd.

  13. Analysis and design of lattice materials for large cord and curvature variations in skin panels of morphing wings

    International Nuclear Information System (INIS)

    Vigliotti, Andrea; Pasini, Damiano

    2015-01-01

    In the past few decades, several concepts for morphing wings have been proposed with the aim of improving the structural and aerodynamic performance of conventional aircraft wings. One of the most interesting challenges in the design of a morphing wing is represented by the skin, which needs to meet specific deformation requirements. In particular when morphing involves changes of cord or curvature, the skin is required to undergo large recoverable deformation in the actuation direction, while maintaining the desired shape and strength in the others. One promising material concept that can meet these specifications is represented by lattice materials. This paper examines the use of alternative planar lattices in the embodiment of a skin panel for cord and camber morphing of an aircraft wing. We use a structural homogenization scheme capable of capturing large geometric nonlinearity, to examine the structural performance of lattice skin concepts, as well as to tune their mechanical properties in desired directions. (technical note)

  14. Optimum Wing Shape of Highly Flexible Morphing Aircraft for Improved Flight Performance

    Science.gov (United States)

    Su, Weihua; Swei, Sean Shan-Min; Zhu, Guoming G.

    2016-01-01

    In this paper, optimum wing bending and torsion deformations are explored for a mission adaptive, highly flexible morphing aircraft. The complete highly flexible aircraft is modeled using a strain-based geometrically nonlinear beam formulation, coupled with unsteady aerodynamics and six-degrees-of-freedom rigid-body motions. Since there are no conventional discrete control surfaces for trimming the flexible aircraft, the design space for searching the optimum wing geometries is enlarged. To achieve high performance flight, the wing geometry is best tailored according to the specific flight mission needs. In this study, the steady level flight and the coordinated turn flight are considered, and the optimum wing deformations with the minimum drag at these flight conditions are searched by utilizing a modal-based optimization procedure, subject to the trim and other constraints. The numerical study verifies the feasibility of the modal-based optimization approach, and shows the resulting optimum wing configuration and its sensitivity under different flight profiles.

  15. Morphing wing structure with controllable twist based on adaptive bending-twist coupling

    Science.gov (United States)

    Raither, Wolfram; Heymanns, Matthias; Bergamini, Andrea; Ermanni, Paolo

    2013-06-01

    A novel semi-passive morphing airfoil concept based on variable bending-twist coupling induced by adaptive shear center location and torsional stiffness is presented. Numerical parametric studies and upscaling show that the concept relying on smart materials permits effective twist control while offering the potential of being lightweight and energy efficient. By means of an experimental characterization of an adaptive beam and a scaled adaptive wing structure, effectiveness and producibility of the structural concept are demonstrated.

  16. Morphing wing structure with controllable twist based on adaptive bending–twist coupling

    International Nuclear Information System (INIS)

    Raither, Wolfram; Heymanns, Matthias; Ermanni, Paolo; Bergamini, Andrea

    2013-01-01

    A novel semi-passive morphing airfoil concept based on variable bending–twist coupling induced by adaptive shear center location and torsional stiffness is presented. Numerical parametric studies and upscaling show that the concept relying on smart materials permits effective twist control while offering the potential of being lightweight and energy efficient. By means of an experimental characterization of an adaptive beam and a scaled adaptive wing structure, effectiveness and producibility of the structural concept are demonstrated. (paper)

  17. Utilization of Optimization for Design of Morphing Wing Structures for Enhanced Flight

    Science.gov (United States)

    Detrick, Matthew Scott

    Conventional aircraft control surfaces constrain maneuverability. This work is a comprehensive study that looks at both smart material and conventional actuation methods to achieve wing twist to potentially improve flight capability using minimal actuation energy while allowing minimal wing deformation under aerodynamic loading. A continuous wing is used in order to reduce drag while allowing the aircraft to more closely approximate the wing deformation used by birds while loitering. The morphing wing for this work consists of a skin supported by an underlying truss structure whose goal is to achieve a given roll moment using less actuation energy than conventional control surfaces. A structural optimization code has been written in order to achieve minimal wing deformation under aerodynamic loading while allowing wing twist under actuation. The multi-objective cost function for the optimization consists of terms that ensure small deformation under aerodynamic loading, small change in airfoil shape during wing twist, a linear variation of wing twist along the length of the wing, small deviation from the desired wing twist, minimal number of truss members, minimal wing weight, and minimal actuation energy. Hydraulic cylinders and a two member linkage driven by a DC motor are tested separately to provide actuation. Since the goal of the current work is simply to provide a roll moment, only one actuator is implemented along the wing span. Optimization is also used to find the best location within the truss structure for the actuator. The active structure produced by optimization is then compared to simulated and experimental results from other researchers as well as characteristics of conventional aircraft.

  18. A Neural Network Controller New Methodology for the ATR-42 Morphing Wing Actuation

    Directory of Open Access Journals (Sweden)

    Abdallah Ben MOSBAH

    2016-06-01

    Full Text Available A morphing wing model is used to improve aircraft performance. To obtain the desired airfoils, electrical actuators are used, which are installed inside of the wing to morph its upper surface in order to obtain its desired shape. In order to achieve this objective, a robust position controller is needed. In this research, a design and test validation of a controller based on neural networks is presented. This controller was composed by a position controller and a current controller to manage the current consumed by the electrical actuators to obtain its desired displacement. The model was tested and validated using simulation and experimental tests. The results obtained with the proposed controller were compared to the results given by the PID controller. Wind tunnel tests were conducted in the Price-Païdoussis Wind Tunnel at the LARCASE laboratory in order to calculate the pressure coefficient distribution on an ATR-42 morphing wing model for different flow conditions. The pressure coefficients obtained experimentally were compared with their numerical values given by XFoil software.

  19. Aeroelastic Modelling and Design of Aeroelastically Tailored and Morphing Wings

    NARCIS (Netherlands)

    Werter, N.P.M.

    2017-01-01

    In order to accommodate the growth in air traffic whilst reducing the impact on the environment, operational efficiency is becoming more and more important in the design of the aircraft of the future. A possible approach to increase the operational efficiency of aircraft wings is the use of

  20. Passively morphing ornithopter wings constructed using a novel compliant spine: design and testing

    International Nuclear Information System (INIS)

    Wissa, A A; Hubbard Jr, J E; Tummala, Y; Frecker, M I

    2012-01-01

    Ornithopters or flapping wing uncrewed aerial vehicles (UAVs) have potential applications in civil and military sectors. Amongst the UAVs, ornithopters have a unique ability to fly in low Reynolds number flight regimes and also have the agility and maneuverability of rotary wing aircraft. In nature, birds achieve such performance by exploiting various wing kinematics known as gaits. The objective of this work is to improve the steady level flight performance of an ornithopter by implementing a continuous vortex gait using a novel passive compliant spine inserted in the ornithopter’s wings. This paper presents an optimal compliant spine concept for ornithopter applications. A quasi-static design optimization procedure was formulated to design the compliant spine. Finite element analysis was performed on a first generation spine and the spine was fabricated. This prototype was then tested by inserting it into an ornithopter’s wing leading edge spar. The effect of inserting the compliant spine into the wings on the electric power required, the aerodynamic loads and the wing kinematics was studied. The ornithopter with the compliant spines inserted in its wings consumed 45% less power and produced an additional 16% of its weight in mean lift compared to the same ornithopter without the compliant spine. The results indicate that this passive morphing approach is promising for improved steady level flight performance. (paper)

  1. Lipogenesis in a wing-polymorphic cricket: Canalization versus morph-specific plasticity as a function of nutritional heterogeneity.

    Science.gov (United States)

    Zera, Anthony J; Clark, Rebecca; Behmer, Spence

    2016-12-01

    The influence of variable nutritional input on life history adaptation is a central, but incompletely understood aspect of life history physiology. The wing-polymorphic cricket, Gryllus firmus, has been extensively studied with respect to the biochemical basis of life history adaptation, in particular, modification of lipid metabolism that underlies the enhanced accumulation of lipid flight fuel in the dispersing morph [LW(f)=long wings with functional flight muscles] relative to the flightless (SW=short-winged) morph. To date, biochemical studies have been undertaken almost exclusively using a single laboratory diet. Thus, the extent to which nutritional heterogeneity, likely experienced in the field, influences this key morph adaptation is unknown. We used the experimental approach of the Geometric Framework for Nutrition and employed 13 diets that differed in the amounts and ratios of protein and carbohydrate to assess how nutrient amount and balance affects morph-specific lipid biosynthesis. Greater lipid biosynthesis and allocation to the soma in the LW(f) compared with the SW morph (1) occurred across the entire protein-carbohydrate landscape and (2) is likely an important contributor to elevated somatic lipid in the LW(f) morph across the entire protein-carbohydrate landscape. Nevertheless, dietary carbohydrate strongly affected lipid biosynthesis in a morph-specific manner (to a greater degree in the LW(f) morph). Lipogenesis in the SW morph may be constrained due to its more limited lipid storage capacity compared to the LW(f) morph. Elevated activity of NADP + -isocitrate dehydrogenase (NADP + -IDH), an enzyme that produces reducing equivalents for lipid biosynthesis, was correlated with and may be an important cause of the increased lipogenesis in the LW(f) morph across most, but not all regions of the protein-carbohydrate landscape. By contrast, ATP-citrate lyase (ACL), an enzyme that catalyzes the first step in the pathway of fatty acid biosynthesis

  2. Numerical and Experimental Validation of the Optimization Methodologies for a Wing-Tip Structure Equipped with Conventional and Morphing Ailerons =

    Science.gov (United States)

    Koreanschi, Andreea

    In order to answer the problem of 'how to reduce the aerospace industry's environment footprint?' new morphing technologies were developed. These technologies were aimed at reducing the aircraft's fuel consumption through reduction of the wing drag. The morphing concept used in the present research consists of replacing the conventional aluminium upper surface of the wing with a flexible composite skin for morphing abilities. For the ATR-42 'Morphing wing' project, the wing models were manufactured entirely from composite materials and the morphing region was optimized for flexibility. In this project two rigid wing models and an active morphing wing model were designed, manufactured and wind tunnel tested. For the CRIAQ MDO 505 project, a full scale wing-tip equipped with two types of ailerons, conventional and morphing, was designed, optimized, manufactured, bench and wind tunnel tested. The morphing concept was applied on a real wing internal structure and incorporated aerodynamic, structural and control constraints specific to a multidisciplinary approach. Numerical optimization, aerodynamic analysis and experimental validation were performed for both the CRIAQ MDO 505 full scale wing-tip demonstrator and the ATR-42 reduced scale wing models. In order to improve the aerodynamic performances of the ATR-42 and CRIAQ MDO 505 wing airfoils, three global optimization algorithms were developed, tested and compared. The three algorithms were: the genetic algorithm, the artificial bee colony and the gradient descent. The algorithms were coupled with the two-dimensional aerodynamic solver XFoil. XFoil is known for its rapid convergence, robustness and use of the semi-empirical e n method for determining the position of the flow transition from laminar to turbulent. Based on the performance comparison between the algorithms, the genetic algorithm was chosen for the optimization of the ATR-42 and CRIAQ MDO 505 wing airfoils. The optimization algorithm was improved during

  3. Inertial attitude control of a bat-like morphing-wing air vehicle.

    Science.gov (United States)

    Colorado, J; Barrientos, A; Rossi, C; Parra, C

    2013-03-01

    This paper presents a novel bat-like unmanned aerial vehicle inspired by the morphing-wing mechanism of bats. The goal of this paper is twofold. Firstly, a modelling framework is introduced for analysing how the robot should manoeuvre by means of changing wing morphology. This allows the definition of requirements for achieving forward and turning flight according to the kinematics of the wing modulation. Secondly, an attitude controller named backstepping+DAF is proposed. Motivated by biological evidence about the influence of wing inertia on the production of body accelerations, the attitude control law incorporates wing inertia information to produce desired roll (ϕ) and pitch (θ) acceleration commands (desired angular acceleration function (DAF)). This novel control approach is aimed at incrementing net body forces (F(net)) that generate propulsion. Simulations and wind-tunnel experimental results have shown an increase of about 23% in net body force production during the wingbeat cycle when the wings are modulated using the DAF as a part of the backstepping control law. Results also confirm accurate attitude tracking in spite of high external disturbances generated by aerodynamic loads at airspeeds up to 5 ms⁻¹.

  4. Inertial attitude control of a bat-like morphing-wing air vehicle

    International Nuclear Information System (INIS)

    Colorado, J; Barrientos, A; Rossi, C; Parra, C

    2013-01-01

    This paper presents a novel bat-like unmanned aerial vehicle inspired by the morphing-wing mechanism of bats. The goal of this paper is twofold. Firstly, a modelling framework is introduced for analysing how the robot should manoeuvre by means of changing wing morphology. This allows the definition of requirements for achieving forward and turning flight according to the kinematics of the wing modulation. Secondly, an attitude controller named backstepping+DAF is proposed. Motivated by biological evidence about the influence of wing inertia on the production of body accelerations, the attitude control law incorporates wing inertia information to produce desired roll (φ) and pitch (θ) acceleration commands (desired angular acceleration function (DAF)). This novel control approach is aimed at incrementing net body forces (F net ) that generate propulsion. Simulations and wind-tunnel experimental results have shown an increase of about 23% in net body force production during the wingbeat cycle when the wings are modulated using the DAF as a part of the backstepping control law. Results also confirm accurate attitude tracking in spite of high external disturbances generated by aerodynamic loads at airspeeds up to 5 ms −1 . (paper)

  5. Bacterial symbionts, Buchnera, and starvation on wing dimorphism in English grain aphid, Sitobion avenae (F.) (Homoptera: Aphididae)

    Science.gov (United States)

    Wing dimorphism in aphids can be affected by multiple cues including both biotic (nutrition, crowding, interspecific interactions, the presence of natural enemies, maternal and transgenerational effects, and alarm pheromone) and abiotic factors (temperature, humidity, and photoperiod). Virtually al...

  6. The influence of natural enemies on wing induction in Aphis fabae and Megoura viciae (Hemiptera: Aphididae).

    Science.gov (United States)

    Kunert, G; Schmoock-Ortlepp, K; Reissmann, U; Creutzburg, S; Weisser, W W

    2008-02-01

    Previous studies have shown that the aphid species, Aphis fabae Scopoli and Megoura viciae Buckton, do not produce winged offspring in the presence of natural enemies, in contrast to results for the pea aphid (Acyrthosiphon pisum (Harris)) and the cotton aphid (Aphis gossypii Glover); but these studies did not involve exposing aphids directly to natural enemies. We exposed colonies of both A. fabae and M. viciae to foraging lacewing (Chrysoperla carnea (Stephens)) larvae and found that the predators did not induce winged morphs among offspring compared to unexposed controls. Colonies of A. fabae responded to an increase in aphid density with increasing winged morph production, while such response was not found for M. viciae. We suggest that different aphid species differ in their susceptibility to natural enemy attack, as well as in their sensitivity to contact.

  7. Viscous-Inviscid Methods in Unsteady Aerodynamic Analysis of Bio-Inspired Morphing Wings

    Science.gov (United States)

    Dhruv, Akash V.

    Flight has been one of the greatest realizations of human imagination, revolutionizing communication and transportation over the years. This has greatly influenced the growth of technology itself, enabling researchers to communicate and share their ideas more effectively, extending the human potential to create more sophisticated systems. While the end product of a sophisticated technology makes our lives easier, its development process presents an array of challenges in itself. In last decade, scientists and engineers have turned towards bio-inspiration to design more efficient and robust aerodynamic systems to enhance the ability of Unmanned Aerial Vehicles (UAVs) to be operated in cluttered environments, where tight maneuverability and controllability are necessary. Effective use of UAVs in domestic airspace will mark the beginning of a new age in communication and transportation. The design of such complex systems necessitates the need for faster and more effective tools to perform preliminary investigations in design, thereby streamlining the design process. This thesis explores the implementation of numerical panel methods for aerodynamic analysis of bio-inspired morphing wings. Numerical panel methods have been one of the earliest forms of computational methods for aerodynamic analysis to be developed. Although the early editions of this method performed only inviscid analysis, the algorithm has matured over the years as a result of contributions made by prominent aerodynamicists. The method discussed in this thesis is influenced by recent advancements in panel methods and incorporates both viscous and inviscid analysis of multi-flap wings. The surface calculation of aerodynamic coefficients makes this method less computationally expensive than traditional Computational Fluid Dynamics (CFD) solvers available, and thus is effective when both speed and accuracy are desired. The morphing wing design, which consists of sequential feather-like flaps installed

  8. Aphid Polyphenisms: Trans-generational Developmental Regulation through Viviparity

    Directory of Open Access Journals (Sweden)

    Kota eOgawa

    2014-01-01

    Full Text Available Polyphenism, in which multiple discrete phenotypes develop from a single genotype, is considered to have contributed to the evolutionary success of aphids. Of the various polyphenisms observed in the complex life cycle of aphids, the reproductive and wing polyphenisms seen in most aphid species are conspicuous. In reproductive polyphenism, the reproductive modes can change between viviparous parthenogenesis and sexual reproduction in response to the photoperiod. Under short-day conditions in autumn, sexual morphs (males and oviparous females are produced parthenogenetically. Winged polyphenism is observed in viviparous generations during summer, when winged or wingless (flightless aphids are produced depending on a variety of environmental conditions (e.g. density, predators. Here, we review the physiological mechanisms underlying reproductive and wing polyphenism in aphids. In reproductive polyphenism, morph determination (male, oviparous or viviparous female within mother aphids is regulated by juvenile hormone (JH titers in the mothers. In wing polyphenism, although JH is considered to play an important role in phenotype determination (winged or wingless, the role is still controversial. In both cases, the acquisition of viviparity in Aphididae is considered to be the basis for maternal regulation of these polyphenisms, and through which environmental cues can be transferred to developing embryos through the physiological state of the mother. Although the mechanisms by which mothers alter the developmental programs of their progeny have not yet been clarified, continued developments in molecular biology will likely unravel these questions.

  9. Effect of the Backward-Facing Step Location on the Aerodynamics of a Morphing Wing

    Directory of Open Access Journals (Sweden)

    Fadi Mishriky

    2016-08-01

    Full Text Available Over the last decade, aircraft morphing technology has drawn a lot of attention in the aerospace community, because it is likely to improve the aerodynamic performance and the versatility of aircraft at different flight regimes. With the fast paced advancements in this field, a parallel stream of research is studying different materials and designs to develop reliable morphing skins. A promising candidate for a viable morphing skin is the sliding skin, where two or more rigid surfaces remain in contact and slide against each other during morphing. The overlapping between each two panels create a backward-facing step on the airfoil surface which has a critical effect on the aerodynamics of the wing. This paper presents a numerical study of the effect of employing a backward-facing step on the suction side of a National Advisory Committee for Aeronautics (NACA 2412 airfoil at a high Reynolds number of 5.9 × 106. The effects of the step location on the lift coefficient, drag coefficient and critical angle of attack are studied to find a favorable location for the step along the chord-wise direction. Results showed that employing a step on the suction side of the NACA 2412 airfoil can adversely affect the aforementioned aerodynamic properties. A drop of 21.1% in value of the lift coefficient and an increase of 120.8% in the drag coefficient were observed in case of a step located at 25% of the chord length. However, these effects are mitigated by shifting the step location towards the trailing edge. Introducing a step on the airfoil caused the airfoil’s thickness to change, which in turn has affected the transition point of the viscous boundary layer from laminar to turbulent. The location of the step, prior or post the transition point, has a noteworthy effect on the pressure and shear stress distribution, and consequently on the values of the lift and drag coefficients.

  10. Optical fiber shape sensing of polyimide skin for a flexible morphing wing.

    Science.gov (United States)

    Sun, Guangkai; Li, Hong; Dong, Mingli; Lou, Xiaoping; Zhu, Lianqing

    2017-11-20

    This paper presents the 3D shape sensing of polyimide thin film skin for a flexible morphing wing using fiber Bragg grating (FBG) sensors. The calibration curves of the FBG sensors are measured experimentally to ensure relative accurate conversion between Bragg wavelength shift (BWS) and bending curvature of the polyimide skin. The reflection spectra of the FBG sensors are measured at different airfoil profiles, and the variation tendency of the BWS values with the airfoil profiles are analyzed. The bending curvatures of the polyimide thin film skin at different airfoil profiles are calculated using the measured BWS values of the FBG sensors and the linear interpolation algorithm. The 3D shapes of the polyimide skin at different airfoil profiles are reconstructed based on the measured bending curvatures and the interpolation and curve fitting functions. The 3D precise visual measurements are conducted using a digital photogrammetry system, and then the correctness of the shape reconstruction results are verified. The results prove that the maximum error between the 3D visual and FBG measurements is less than 5%. The FBG sensing method is effective for the shape sensing of polyimide skin for flexible morphing wing.

  11. Analytical modeling and experimental evaluation of a passively morphing ornithopter wing

    Science.gov (United States)

    Wissa, Aimy A.

    Ornithopters or flapping wing Unmanned Aerial Vehicles (UAVs) have potential applications in both civil and military sectors. Amongst all categories of UAVs, ornithopters have a unique ability to fly in low Reynolds number flight regimes and have the agility and maneuverability of rotary wing aircraft. In nature, birds achieve such performance by exploiting various wing kinematics known as gaits. The objective of this work was to improve the steady level flight wing performance of an ornithopter by implementing the Continuous Vortex Gait (CVG) using a novel passive compliant spine. The CVG is a set of bio-inspired kinematics that natural flyers use to produce lift and thrust during steady level flight. A significant contribution of this work was the recognition that the CVG is an avian gait that could be achieved using a passive morphing mechanism. In contrast to rigid-link mechanisms and active approaches, reported by other researchers in the open literature, passive morphing mechanisms require no additional energy expenditure, while introducing minimal weight addition and complexity. During the execution of the CVG, the avian wing wrist is the primary joint responsible for the wing shape changes. Thus a compliant mechanism, called a compliant spine, was fabricated, and integrated in the ornithopter's wing leading edge spar where an avian wrist would normally exist, namely at 37% of the wing half span. Each compliant spine was designed to be flexible in bending during the wing upstroke and stiff in bending during the wing downstroke. Inserting a variable stiffness compliant mechanism in the leading edge (LE) spar of the ornithopter could affect its structural stability. An analytical model was developed to determine the structural stability of the ornithopter LE spar. The model was validated using experimental measurements. The LE spar equations of motion were then reformulated into Mathieu's equation and the LE spar was proven to be structurally stable with a

  12. Do asexual morphs of the peach-potato aphid, Myzus persicae, utilise the aphid sex pheromone? Behavioural and electrophysiological responses of M. persicae virginoparae to (4aS,7S,7aR)-nepetalactone and its effect on aphid performance.

    Science.gov (United States)

    Fernández-Grandon, G Mandela; Woodcock, Christine M; Poppy, Guy M

    2013-08-01

    The aphid sex pheromone component (4aS,7S,7aR)-nepetalactone is considered to be a potential tool for enhancing biological control of aphids. Studies have confirmed its potential to attract parasitoids, increase parasitism rates in the field and also alter the spatial distribution of parasitoids. An important aspect that has been overlooked is the impact that the introduction of nepetalactone may have on aphid populations already present in field or glasshouse environments. The most prevalent pest aphid populations in glasshouse and field environments are the asexual morphs, which are capable of exponential growth if populations are not controlled. The short-term implications of the sex pheromone on asexual aphids were observed through their behavioural response. Using Y-tube olfactometry, it is shown that virginoparae of the peach-potato aphid, Myzus persicae, are repelled by high concentrations of nepetalactone. Long-term effects of the pheromone which may span the aphid's life, or even generations, were assessed via mean relative growth rate (MRGR) and the intrinsic rate of natural increase (rm). Electroantennography also demonstrated that asexual female aphids are able to detect aphid sex pheromone components. To our knowledge, this is the first time it has been reported that M. persicae virginoparae are able to detect aphid sex pheromone components or that their behavioural response and/or performance has been studied. The implications of these results and their significance in understanding semiochemical communication are discussed.

  13. Toward the bi-modal camber morphing of large aircraft wing flaps: the CleanSky experience

    Science.gov (United States)

    Pecora, R.; Amoroso, F.; Magnifico, M.

    2016-04-01

    The Green Regional Aircraft (GRA), one of the six CleanSky platforms, represents the largest European effort toward the greening of next generation air transportation through the implementation of advanced aircraft technologies. In this framework researches were carried out to develop an innovative wing flap enabling airfoil morphing according to two different modes depending on aircraft flight condition and flap setting: - Camber morphing mode. Morphing of the flap camber to enhance high-lift performances during take-off and landing (flap deployed); - Tab-like morphing mode. Upwards and downwards deflection of the flap tip during cruise (flap stowed) for load control at high speed and consequent optimization of aerodynamic efficiency. A true-scale flap segment of a reference aircraft (EASA CS25 category) was selected as investigation domain for the new architecture in order to duly face the challenges posed by real wing installation issues especially with reference to the tapered geometrical layout and 3D aerodynamic loads distributions. The investigation domain covered the flap region spanning 3.6 m from the wing kink and resulted characterized by a taper ratio equal to 0.75 with a root chord of 1.2 m. High TRL solutions for the adaptive structure, actuation and control system were duly analyzed and integrated while assuring overall device compliance with industrial standards and applicable airworthiness requirements.

  14. Design, Development and Tests in Real Time of Control Methodologies for a Morphing Wing in Wind Tunnel =

    Science.gov (United States)

    Tchatchueng Kammegne, Michel Joel

    In order to leave a cleaner environmental space to future generations, the international community has been mobilized to find green solutions that are effective and feasible in all sectors. The CRIAQ MDO505 project was initiated to test the morphing wingtip (wing and aileron) technology as one of these possible solutions. The main objectives of this project are: the design and manufacturing of a morphing wing prototype, the extension and control of the laminar region over the extrados, and to compare the effects of morphing and rigid aileron in terms of lift, drag and pressure distributions. The advantage of the extension of the laminar region over a wing is the drag reduction that results by delaying the transition towards its trailing edge. The location of the transition region depends on the flight case and it is controlled, for a morphing wing, via the actuators positions and displacements. Therefore, this thesis work focuses on the control of the actuators positions and displacements. This thesis presents essentially the modeling, instrumentation and wind tunnel testing results. Three series of wind tunnel tests with different values of aileron deflection angle, angle of attack and Mach number have been performed in the subsonic wind tunnel of the IAR-NRC. The used wing airfoil consisted of stringers, ribs, spars and a flexible upper surface mad of composite materials (glass fiber carbon), a rigid aileron and flexible aileron. The aileron was able to move between +/-6 degrees. The demonstrator's span measures 1.5 m and its chord measures 1.5 m. Structural analyses have been performed to determine the plies orientation, and the number of fiberglass layers for the flexible skin. These analyses allowed also to determine the actuator's forces to push and pull the wing upper surface. The 2D XFoil and 3D solvers Fluent were used to find the optimized airfoil and the optimal location of the transition for each flight case. Based on the analyses done by the

  15. The integrative effects of population density, photoperiod, temperature, and host plant on the induction of alate aphids in Schizaphis graminum.

    Science.gov (United States)

    An, Chunju; Fei, Xiaodong; Chen, Wenfeng; Zhao, Zhangwu

    2012-04-01

    The wheat aphid Schizaphis graminum (Rondani) displays wing dimorphism with both winged and wingless adult morphs. The winged morph is an adaptive microevolutionary response to undesirable environmental conditions, including undesirable population density, photoperiod, temperature, and host plant. Here we studied the integrative effects of population density, photoperiod, temperature, and host plant on the induction of alate aphids in S. graminum. The present results show that these four factors all play roles in inducing alate aphids in S. graminum but population density is the most important under almost all circumstances. In importance, population density is followed by photoperiod, host plant, and temperature, in that order. These results indicate that ambient environmental factors are highly important to stimulation of alate aphids in S. graminum, especially when population density reaches 64 individuals per leaf. © 2012 Wiley Periodicals, Inc.

  16. Constitutive emission of the aphid alarm pheromone, (E)-β-farnesene, from plants does not serve as a direct defense against aphids.

    Science.gov (United States)

    Kunert, Grit; Reinhold, Carolina; Gershenzon, Jonathan

    2010-11-23

    The sesquiterpene, (E)-β-farnesene (EBF), is the principal component of the alarm pheromone of many aphid species. Released when aphids are attacked by enemies, EBF leads aphids to undertake predator avoidance behaviors and to produce more winged offspring that can leave the plant. Many plants also release EBF as a volatile, and so it has been proposed that this compound could act to defend plants against aphid infestation by 1) deterring aphids from settling, 2) reducing aphid performance due to frequent interruption of feeding and 3) inducing the production of more winged offspring. Here we tested the costs and benefits of EBF as a defense against the green peach aphid, Myzus persicae, using transgenic Arabidopsis thaliana lines engineered to continuously emit EBF. No metabolic costs of EBF synthesis could be detected in these plants as they showed no differences in growth or seed production from wild-type controls under two fertilizer regimes. Likewise, no evidence was found for the ability of EBF to directly defend the plant against aphids. EBF emission did not significantly repel winged or wingless morphs from settling on plants. Nor did EBF reduce aphid performance, measured as reproduction, or lead to an increase in the proportion of winged offspring. The lack of any defensive effect of EBF in this study might be due to the fact that natural enemy attack on individual aphids leads to a pulsed emission, but the transgenic lines tested continuously produce EBF to which aphids may become habituated. Thus our results provide no support for the hypothesis that plant emission of the aphid alarm pheromone EBF is a direct defense against aphids. However, there is scattered evidence elsewhere in the literature suggesting that EBF emission might serve as an indirect defense by attracting aphid predators.

  17. Constitutive emission of the aphid alarm pheromone, (E-β-farnesene, from plants does not serve as a direct defense against aphids

    Directory of Open Access Journals (Sweden)

    Gershenzon Jonathan

    2010-11-01

    Full Text Available Abstract Background The sesquiterpene, (E-β-farnesene (EBF, is the principal component of the alarm pheromone of many aphid species. Released when aphids are attacked by enemies, EBF leads aphids to undertake predator avoidance behaviors and to produce more winged offspring that can leave the plant. Many plants also release EBF as a volatile, and so it has been proposed that this compound could act to defend plants against aphid infestation by 1 deterring aphids from settling, 2 reducing aphid performance due to frequent interruption of feeding and 3 inducing the production of more winged offspring. Here we tested the costs and benefits of EBF as a defense against the green peach aphid, Myzus persicae, using transgenic Arabidopsis thaliana lines engineered to continuously emit EBF. Results No metabolic costs of EBF synthesis could be detected in these plants as they showed no differences in growth or seed production from wild-type controls under two fertilizer regimes. Likewise, no evidence was found for the ability of EBF to directly defend the plant against aphids. EBF emission did not significantly repel winged or wingless morphs from settling on plants. Nor did EBF reduce aphid performance, measured as reproduction, or lead to an increase in the proportion of winged offspring. Conclusions The lack of any defensive effect of EBF in this study might be due to the fact that natural enemy attack on individual aphids leads to a pulsed emission, but the transgenic lines tested continuously produce EBF to which aphids may become habituated. Thus our results provide no support for the hypothesis that plant emission of the aphid alarm pheromone EBF is a direct defense against aphids. However, there is scattered evidence elsewhere in the literature suggesting that EBF emission might serve as an indirect defense by attracting aphid predators.

  18. Comparative profiling of microRNAs in the winged and wingless English grain aphid, Sitobion avenae (F.) (Homoptera: Aphididae)

    Science.gov (United States)

    English green aphid, Sitobion avenae (F.), show a classic polyphenic wing dimorphism among isogenic adults that is an intriguing model for the study of morphological plasticity in response to the environment. Short non-coding microRNA (miRNA) molecules regulate gene expression by post-transcriptiona...

  19. Morphing Wing Structural Optimization Using Opposite-Based Population-Based Incremental Learning and Multigrid Ground Elements

    Directory of Open Access Journals (Sweden)

    S. Sleesongsom

    2015-01-01

    Full Text Available This paper has twin aims. Firstly, a multigrid design approach for optimization of an unconventional morphing wing is proposed. The structural design problem is assigned to optimize wing mass, lift effectiveness, and buckling factor subject to structural safety requirements. Design variables consist of partial topology, nodal positions, and component sizes of a wing internal structure. Such a design process can be accomplished by using multiple resolutions of ground elements, which is called a multigrid approach. Secondly, an opposite-based multiobjective population-based incremental learning (OMPBIL is proposed for comparison with the original multiobjective population-based incremental learning (MPBIL. Multiobjective design problems with single-grid and multigrid design variables are then posed and tackled by OMPBIL and MPBIL. The results show that using OMPBIL in combination with a multigrid design approach is the best design strategy. OMPBIL is superior to MPBIL since the former provides better population diversity. Aeroelastic trim for an elastic morphing wing is also presented.

  20. Morphing Wing Design with an Innovative Three-Dimensional Warping Actuation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced wing configurations where traditional control surfaces are replaced by dynamically controlled distribution of wing twist and/or camber can provide...

  1. Comparative transcriptional analysis of asexual and sexual morphs reveals possible mechanisms in reproductive polyphenism of the cotton aphid.

    Directory of Open Access Journals (Sweden)

    Li-Jun Liu

    Full Text Available Aphids, the destructive insect pests in the agriculture, horticulture and forestry, are capable of reproducing asexually and sexually upon environmental change. However, the molecular basis of aphid reproductive mode switch remains an enigma. Here we report a comparative analysis of differential gene expression profiling among parthenogenetic females, gynoparae and sexual females of the cotton aphid Aphis gossypii, using the RNA-seq approach with next-generation sequencing platforms, followed by RT-qPCR. At the cutoff criteria of fold change ≥2 and P<0.01, we identified 741 up- and 879 down-regulated genes in gynoparae versus parthenogenetic females, 2,101 up- and 2,210 down-regulated genes in sexual females compared to gynoparae, and 1,614 up- and 2,238 down-regulated genes in sexual females relative to parthenogenetic females. Gene ontology category and KEGG pathway analysis suggest the involvement of differentially expressed genes in multiple cellular signaling pathways into the reproductive mode transition, including phototransduction, cuticle composition, progesterone-mediated oocyte maturation and endocrine regulation. This study forms a basis for deciphering the molecular mechanisms underlying the shift from asexual to sexual reproduction in the cotton aphid. It also provides valuable resources for future studies on this host-alternating aphid species, and the insight into the understanding of reproductive mode plasticity in different aphid species.

  2. Exposure to bacterial signals does not alter pea aphids' survival upon a second challenge or investment in production of winged offspring.

    Directory of Open Access Journals (Sweden)

    Bas ter Braak

    Full Text Available Pea aphids have an obligate nutritional symbiosis with the bacteria Buchneraaphidicola and frequently also harbor one or more facultative symbionts. Aphids are also susceptible to bacterial pathogen infections, and it has been suggested that aphids have a limited immune response towards such pathogen infections compared to other, more well-studied insects. However, aphids do possess at least some of the genes known to be involved in bacterial immune responses in other insects, and immune-competent hemocytes. One possibility is that immune priming with microbial elicitors could stimulate immune protection against subsequent bacterial infections, as has been observed in several other insect systems. To address this hypothesis we challenged aphids with bacterial immune elicitors twenty-four hours prior to live bacterial pathogen infections and then compared their survival rates to aphids that were not pre-exposed to bacterial signals. Using two aphid genotypes, we found no evidence for immune protection conferred by immune priming during infections with either Serratia marcescens or with Escherichia coli. Immune priming was not altered by the presence of facultative, beneficial symbionts in the aphids. In the absence of inducible immune protection, aphids may allocate energy towards other defense traits, including production of offspring with wings that could escape deteriorating conditions. To test this, we monitored the ratio of winged to unwinged offspring produced by adult mothers of a single clone that had been exposed to bacterial immune elicitors, to live E. coli infections or to no challenge. We found no correlation between immune challenge and winged offspring production, suggesting that this mechanism of defense, which functions upon exposure to fungal pathogens, is not central to aphid responses to bacterial infections.

  3. Experimental investigation of the dynamics of a hybrid morphing wing: time resolved particle image velocimetry and force measures

    Science.gov (United States)

    Jodin, Gurvan; Scheller, Johannes; Rouchon, Jean-François; Braza, Marianna; Mit Collaboration; Imft Collaboration; Laplace Collaboration

    2016-11-01

    A quantitative characterization of the effects obtained by high frequency-low amplitude trailing edge actuation is performed. Particle image velocimetry, as well as pressure and aerodynamic force measurements, are carried out on an airfoil model. This hybrid morphing wing model is equipped with both trailing edge piezoelectric-actuators and camber control shape memory alloy actuators. It will be shown that this actuation allows for an effective manipulation of the wake turbulent structures. Frequency domain analysis and proper orthogonal decomposition show that proper actuating reduces the energy dissipation by favoring more coherent vortical structures. This modification in the airflow dynamics eventually allows for a tapering of the wake thickness compared to the baseline configuration. Hence, drag reductions relative to the non-actuated trailing edge configuration are observed. Massachusetts Institute of Technology.

  4. Flight Testing of Novel Compliant Spines for Passive Wing Morphing on Ornithopters

    Science.gov (United States)

    Wissa, Aimy; Guerreiro, Nelson; Grauer, Jared; Altenbuchner, Cornelia; Hubbard, James E., Jr.; Tummala, Yashwanth; Frecker, Mary; Roberts, Richard

    2013-01-01

    Unmanned Aerial Vehicles (UAVs) are proliferating in both the civil and military markets. Flapping wing UAVs, or ornithopters, have the potential to combine the agility and maneuverability of rotary wing aircraft with excellent performance in low Reynolds number flight regimes. The purpose of this paper is to present new free flight experimental results for an ornithopter equipped with one degree of freedom (1DOF) compliant spines that were designed and optimized in terms of mass, maximum von-Mises stress, and desired wing bending deflections. The spines were inserted in an experimental ornithopter wing spar in order to achieve a set of desired kinematics during the up and down strokes of a flapping cycle. The ornithopter was flown at Wright Patterson Air Force Base in the Air Force Research Laboratory Small Unmanned Air Systems (SUAS) indoor flight facility. Vicon motion tracking cameras were used to track the motion of the vehicle for five different wing configurations. The effect of the presence of the compliant spine on wing kinematics and leading edge spar deflection during flight is presented. Results show that the ornithopter with the compliant spine inserted in its wing reduced the body acceleration during the upstroke which translates into overall lift gains.

  5. Short-term consequences of reproductive mode variation on the genetic architecture of energy metabolism and life-history traits in the pea aphid.

    Science.gov (United States)

    Artacho, P; Figueroa, C C; Cortes, P A; Simon, J-C; Nespolo, R F

    2011-07-01

    Cyclically parthenogenetic animals such as aphids are able alternating sexual and asexual reproduction during its life cycle, and represent good models for studying short-term evolutionary consequences of sex. In aphids, different morphs, whether sexual or asexual, winged or wingless, are produced in response to specific environmental cues. The production of these morphs could imply a differential energy investment between the two reproductive phases (i.e., sexual and asexual), which can also be interpreted in terms of changes in genetic variation and/or trade-offs between the associated traits. In this study we compared the G-matrices of energy metabolism, life-history traits and morph production in 10 clonal lineages (genotypes) of the pea aphid, Acyrthosiphon pisum, during both sexual and asexual phases. The heritabilities (broad-sense) were significant for almost all traits in both phases; however the only significant genetic correlation we found was a positive correlation between resting metabolic rate and production of winged parthenogenetic females during the asexual phase. These results suggest the pea aphid shows some lineage specialization in terms of energy costs, but a higher specialization in the production of the different morphs (e.g., winged parthenogenetic females). Moreover, the production of winged females during the asexual phase appears to be more costly than wingless females. Finally, the structures of genetic variance-covariance matrices differed between both phases. These differences were mainly due to the correlation between resting metabolic rate and winged parthenogenetic females in the asexual phase. This structural difference would be indicating that energy allocation rules changes between phases, emphasizing the dispersion role of asexual morphs. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Morphing morphing faces

    NARCIS (Netherlands)

    Lier, R.J. van

    2009-01-01

    We have made cyclic morphing animations using two different faces. The morphing animations gradually evolved from one face to the other, and vice versa. When free viewing, the perceived changes were not very large, but the changes could easily be observed. Observers were asked to fixate on a dot

  7. Variable Camber Morphing Wings

    Science.gov (United States)

    2016-02-02

    MG UMA REVISÃO SOBRE A TECNOLOGIA DE AERONAVES DE GEOMETRIA ADAPTATIVA Thiago de Paula Sales, Laboratório de Mecânica de Estruturas Prof. J. E. T...relacionados à tecnologia de aeronaves de geometria adap- tativa. Inicialmente, uma breve contextualização histórica é apresentada. Na sequência, relações...Alves Rade Uma Revisão Sobre a Tecnologia de Aeronaves de Geometria Adaptativa controle de voo, por exemplo. Com isso, superfícies auxiliares, como

  8. Optimization and design of an aircraft’s morphing wing-tip demonstrator for drag reduction at low speed, Part I – Aerodynamic optimization using genetic, bee colony and gradient descent algorithms

    Directory of Open Access Journals (Sweden)

    Andreea Koreanschi

    2017-02-01

    Full Text Available In this paper, an ‘in-house’ genetic algorithm is described and applied to an optimization problem for improving the aerodynamic performances of an aircraft wing tip through upper surface morphing. The algorithm’s performances were studied from the convergence point of view, in accordance with design conditions. The algorithm was compared to two other optimization methods, namely the artificial bee colony and a gradient method, for two optimization objectives, and the results of the optimizations with each of the three methods were plotted on response surfaces obtained with the Monte Carlo method, to show that they were situated in the global optimum region. The optimization results for 16 wind tunnel test cases and 2 objective functions were presented. The 16 cases used for the optimizations were included in the experimental test plan for the morphing wing-tip demonstrator, and the results obtained using the displacements given by the optimizations were evaluated.

  9. Optimization and design of an aircraft's morphing wing-tip demonstrator for drag reduction at low speeds, Part II - Experimental validation using Infra-Red transition measurement from Wind Tunnel tests

    OpenAIRE

    Andreea Koreanschi; Oliviu Sugar Gabor; Joran Acotto; Guillaume Brianchon; Gregoire Portier; Ruxandra Mihaela Botez; Mahmoud Mamou; Youssef Mebarki

    2017-01-01

    In the present paper, an ‘in-house’ genetic algorithm was numerically and experimentally validated. The genetic algorithm was applied to an optimization problem for improving the aerodynamic performances of an aircraft wing tip through upper surface morphing. The optimization was performed for 16 flight cases expressed in terms of various combinations of speeds, angles of attack and aileron deflections. The displacements resulted from the optimization were used during the wind tunnel tests of...

  10. Expansion of genes encoding piRNA-associated argonaute proteins in the pea aphid: diversification of expression profiles in different plastic morphs.

    Directory of Open Access Journals (Sweden)

    Hsiao-Ling Lu

    Full Text Available Piwi-interacting RNAs (piRNAs are known to regulate transposon activity in germ cells of several animal models that propagate sexually. However, the role of piRNAs during asexual reproduction remains almost unknown. Aphids that can alternate sexual and asexual reproduction cycles in response to seasonal changes of photoperiod provide a unique opportunity to study piRNAs and the piRNA pathway in both reproductive modes. Taking advantage of the recently sequenced genome of the pea aphid Acyrthosiphon pisum, we found an unusually large lineage-specific expansion of genes encoding the Piwi sub-clade of Argonaute proteins. In situ hybridisation showed differential expressions between the duplicated piwi copies: while Api-piwi2 and Api-piwi6 are "specialised" in germ cells their most closely related copy, respectively Api-piwi5 and Api-piwi3, are expressed in the somatic cells. The differential expression was also identified in duplicated ago3: Api-ago3a in germ cells and Api-ago3b in somatic cells. Moreover, analyses of expression profiles of the expanded piwi and ago3 genes by semi-quantitative RT-PCR showed that expressions varied according to the reproductive types. These specific expression patterns suggest that expanded aphid piwi and ago3 genes have distinct roles in asexual and sexual reproduction.

  11. Optimization and design of an aircraft's morphing wing-tip demonstrator for drag reduction at low speeds, Part II - Experimental validation using Infra-Red transition measurement from Wind Tunnel tests

    Directory of Open Access Journals (Sweden)

    Andreea Koreanschi

    2017-02-01

    Full Text Available In the present paper, an ‘in-house’ genetic algorithm was numerically and experimentally validated. The genetic algorithm was applied to an optimization problem for improving the aerodynamic performances of an aircraft wing tip through upper surface morphing. The optimization was performed for 16 flight cases expressed in terms of various combinations of speeds, angles of attack and aileron deflections. The displacements resulted from the optimization were used during the wind tunnel tests of the wing tip demonstrator for the actuators control to change the upper surface shape of the wing. The results of the optimization of the flow behavior for the airfoil morphing upper-surface problem were validated with wind tunnel experimental transition results obtained with infra-red Thermography on the wing-tip demonstrator. The validation proved that the 2D numerical optimization using the ‘in-house’ genetic algorithm was an appropriate tool in improving various aspects of a wing’s aerodynamic performances.

  12. Flight feather attachment in rock pigeons (Columba livia): covert feathers and smooth muscle coordinate a morphing wing.

    Science.gov (United States)

    Hieronymus, Tobin L

    2016-11-01

    Mechanisms for passively coordinating forelimb movements and flight feather abduction and adduction have been described separately from both in vivo and ex vivo studies. Skeletal coordination has been identified as a way for birds to simplify the neuromotor task of controlling flight stroke, but an understanding of the relationship between skeletal coordination and the coordination of the aerodynamic control surface (the flight feathers) has been slow to materialize. This break between the biomechanical and aerodynamic approaches - between skeletal kinematics and airfoil shape - has hindered the study of dynamic flight behaviors. Here I use dissection and histology to identify previously overlooked interconnections between musculoskeletal elements and flight feathers. Many of these structures are well-placed to directly link elements of the passive musculoskeletal coordination system with flight feather movements. Small bundles of smooth muscle form prominent connections between upper forearm coverts (deck feathers) and the ulna, as well as the majority of interconnections between major flight feathers of the hand. Abundant smooth muscle may play a role in efficient maintenance of folded wing posture, and may also provide an autonomically regulated means of tuning wing shape and aeroelastic behavior in flight. The pattern of muscular and ligamentous linkages of flight feathers to underlying muscle and bone may provide predictable passive guidance for the shape of the airfoil during flight stroke. The structures described here provide an anatomical touchstone for in vivo experimental tests of wing surface coordination in an extensively researched avian model species. © 2016 Anatomical Society.

  13. Airfoil optimization for morphing aircraft

    Science.gov (United States)

    Namgoong, Howoong

    Continuous variation of the aircraft wing shape to improve aerodynamic performance over a wide range of flight conditions is one of the objectives of morphing aircraft design efforts. This is being pursued because of the development of new materials and actuation systems that might allow this shape change. The main purpose of this research is to establish appropriate problem formulations and optimization strategies to design an airfoil for morphing aircraft that include the energy required for shape change. A morphing aircraft can deform its wing shape, so the aircraft wing has different optimum shapes as the flight condition changes. The actuation energy needed for moving the airfoil surface is modeled and used as another design objective. Several multi-objective approaches are applied to a low-speed, incompressible flow problem and to a problem involving low-speed and transonic flow. The resulting solutions provide the best tradeoff between low drag, high energy and higher drag, low energy sets of airfoil shapes. From this range of solutions, design decisions can be made about how much energy is needed to achieve a desired aerodynamic performance. Additionally, an approach to model aerodynamic work, which would be more realistic and may allow using pressure on the airfoil to assist a morphing shape change, was formulated and used as part of the energy objective. These results suggest that it may be possible to design a morphing airfoil that exploits the airflow to reduce actuator energy.

  14. Deformation measurement in the wind tunnel for an UAV leading edge with a morphing mechanism

    NARCIS (Netherlands)

    Radestock, M.; Riemenschneider, J.; Monner, H.P.; Huxdorf, O.; Werter, N.P.M.; De Breuker, R.

    2016-01-01

    In a wind tunnel experiment a morphing wing with span extension and camber morphing was investigated. The considered aircraft is an unmanned aerial vehicle (UAV) with a span of 4 m. During the investigations a half wing model was analysed with pressure and structural measurement. The half wing model

  15. Aggressive mimicry coexists with mutualism in an aphid

    Science.gov (United States)

    Salazar, Adrián; Fürstenau, Benjamin; Quero, Carmen; Pérez-Hidalgo, Nicolás; Carazo, Pau; Font, Enrique; Martínez-Torres, David

    2015-01-01

    Understanding the evolutionary transition from interspecific exploitation to cooperation is a major challenge in evolutionary biology. Ant–aphid relationships represent an ideal system to this end because they encompass a coevolutionary continuum of interactions ranging from mutualism to antagonism. In this study, we report an unprecedented interaction along this continuum: aggressive mimicry in aphids. We show that two morphs clonally produced by the aphid Paracletus cimiciformis during its root-dwelling phase establish relationships with ants at opposite sides of the mutualism–antagonism continuum. Although one of these morphs exhibits the conventional trophobiotic (mutualistic) relationship with ants of the genus Tetramorium, aphids of the alternative morph are transported by the ants to their brood chamber and cared for as if they were true ant larvae. Gas chromatography-mass spectrometry analyses reveal that the innate cuticular hydrocarbon profile of the mimic morph resembles the profile of ant larvae more than that of the alternative, genetically identical nonmimic morph. Furthermore, we show that, once in the brood chamber, mimic aphids suck on ant larva hemolymph. These results not only add aphids to the limited list of arthropods known to biosynthesize the cuticular chemicals of their deceived hosts to exploit their resources but describe a remarkable case of plastic aggressive mimicry. The present work adds a previously unidentified dimension to the classical textbook paradigm of aphid–ant relationships by showcasing a complex system at the evolutionary interface between cooperation and exploitation. PMID:25583474

  16. Development of an Integrated Aeroelastic Multibody Morphing Simulation Tool (Postprint)

    National Research Council Canada - National Science Library

    Reich, Gregory W; Bowman, Jason C; Sanders, Brian; Frank, Geoffrey J

    2007-01-01

    .... Also discussed are current-generation tools for modeling vehicle flight and illustrations of how these tools are as yet too immature for modeling of the flight of an aircraft during morphing of the wings...

  17. Development of a morphing flap using shape memory alloy actuators: the aerodynamic characteristics of a morphing flap

    International Nuclear Information System (INIS)

    Ko, Seung-Hee; Bae, Jae-Sung; Rho, Jin-Ho

    2014-01-01

    The discontinuous contour of a wing with conventional flaps diminishes the aerodynamic performance of an aircraft. A wing with a continuous contour does not experience extreme flow stream fluctuations during flight, and consequently has good aerodynamic characteristics. In this study, a morphing flap using shape memory alloy actuators is proposed, designed and fabricated, and its aerodynamic characteristics are investigated using aerodynamic analyses and wind tunnel tests. The ribs of the morphing flap are designed and fabricated with multiple elements joined together in a way that allows relative rotations of adjacent elements and forms a smooth contour of the morphing flap. The aerodynamic analyses of this multiple-element morphing-flap wing are performed using XFLR pro; its aerodynamic performance is compared with that of a mechanical-flap wing, and is measured through wind-tunnel tests. (papers)

  18. Experimental testing of spanwise morphing trailing edge concept

    Science.gov (United States)

    Pankonien, Alexander; Inman, Daniel J.

    2013-04-01

    Aircraft wings with smooth, hinge-less morphing ailerons exhibit increased chordwise aerodynamic efficiency over conventional hinged ailerons. Ideally, the wing would also use these morphing ailerons to smoothly vary its airfoil shape between spanwise stations to optimize the lift distribution and further increase aerodynamic efficiency. However, the mechanical complexity or added weight of achieving such a design has traditionally exceeded the potential aerodynamic gains. By expanding upon the previously developed cascading bimorph concept, this work uses embedded Macro-Fiber Composites and a flexure box mechanism, created using multi-material 3D printing, to achieve the Spanwise Morphing Trailing Edge (SMTE) concept. The morphing actuators are spaced spanwise along the wing with an elastomer spanning the gaps between them, which allows for optimization of the spanwise lift distribution while maintaining the continuity and efficiency of the morphing trailing edge. The concept is implemented in a representative section of a UAV wing with a 305 mm chord. A novel honeycomb skin is created from an elastomeric material using a 3D printer. The actuation capabilities of the concept are evaluated with and without spanning material on a test stand, free of aerodynamic loads. In addition, the actuation restrictions of the spanning elastomer, necessary in adapting the morphing concept from 2D to 3D, are characterized. Initial aerodynamic results from the 1'×1' wind-tunnel also show the effects of aerodynamic loading on the actuation range of the SMTE concept for uniform morphing.

  19. Long Chain Alcohols Produced by Trichoderma citrinoviride Have Phagodeterrent Activity Against the Bird Cherry-Oat Aphid Rhopalosiphum padi

    Directory of Open Access Journals (Sweden)

    Sonia eGanassi

    2016-03-01

    Full Text Available In this study we report the effects of fungal metabolites isolated from cultures of the fungus Trichoderma citrinoviride ITEM 4484 on the feeding preference of the aphid Rhopalosiphum padi, a major pest of cereal crops. Different phagodeterrent metabolites were purified by a combination of direct and reverse phase column chromatography and thin-layer chromatography. Chemical investigations, by spectroscopic and chemical methods, led to the identification of different long chain primary alcohols (LCOHs of the general formula R-OH, wherein R is a long, unbranched, unsubstituted, linear aliphatic group. LCOHs have been reported as components of lepidopteran pheromone blends, but their phagodeterrent effect to aphids is herein reported for the first time. We studied the effects of LCOHs on R. padi by behavioral and electrophysiological bioassays. Feeding preference tests that were carried out with winged and wingless morphs of R. padi showed that LCOHs have a distinctly high phagodeterrent activity and significantly restrain aphids from settling on treated leaves already at a concentration as low as 0.15 mM (0.036 g/l. The results of different electrophysiological analyses indicate that taste receptor neurons located on the aphid tarsomeres are involved in the LCOHs perception. Behavioral assays carried out with some commercial agrochemicals, including azadirachtin A, pyrethrum and mineral oil based products, in combination with 1-hexadecanol, the LCOH most abundantly produced by T. citrinoviride ITEM 4484, showed that these different active principles can be applied together, resulting in a useful increase of the phagodeterrent effect. Therefore these compounds can be profitably utilized for novel applications in biotechnical control of aphid pests. The LCOHs tested have no chiral centers and therefore can be obtained in good yields and at low cost through chemical synthesis, beside than from natural sources.

  20. Development of a wingless morph in the ladybird beetle, Adalia bipunctata

    NARCIS (Netherlands)

    Lommen, S.T.E.; Saenko, S.V.; Tomoyasu, Y.

    2009-01-01

    Many taxa of winged insects have independently lost the ability to fly and often possess reduced wings. Species exhibiting natural variation in wing morphology provide opportunities to investigate the genetics and developmental processes underlying the evolution of alternative wing morphs. Although

  1. Aphid performance changes with plant defense mediated by Cucumber mosaic virus titer.

    Science.gov (United States)

    Shi, Xiaobin; Gao, Yang; Yan, Shuo; Tang, Xin; Zhou, Xuguo; Zhang, Deyong; Liu, Yong

    2016-04-22

    Cucumber mosaic virus (CMV) causes appreciable losses in vegetables, ornamentals and agricultural crops. The green peach aphid, Myzus persicae Sulzer (Aphididae) is one of the most efficient vectors for CMV. The transmission ecology of aphid-vectored CMV has been well investigated. However, the detailed description of the dynamic change in the plant-CMV-aphid interaction associated with plant defense and virus epidemics is not well known. In this report, we investigated the relationship of virus titer with plant defense of salicylic acid (SA) and jasmonic acid (JA) during the different infection time and their interaction with aphids in CMV-infected tobacco plants. Our results showed that aphid performance changed with virus titer and plant defense on CMV-inoculated plants. At first, plant defense was low and aphid number increased gradually. The plant defense of SA signaling pathway was induced when virus titer was at a high level, and aphid performance was correspondingly reduced. Additionally, the winged aphids were increased. Our results showed that aphid performance was reduced due to the induced plant defense mediated by Cucumber mosaic virus titer. Additionally, some wingless aphids became to winged aphids. In this way CMV could be transmitted with the migration of winged aphids. We should take measures to prevent aphids in the early stage of their occurrence in the field to prevent virus outbreak.

  2. Mechanisms and actuators for rotorcraft blade morphing

    Science.gov (United States)

    Vocke, Robert D., III

    The idea of improved fight performance through changes in the control surfaces dates back to the advent of aviation with the Wright brothers' pioneering work on "wing warping," but it was not until the recent progress in material and actuator development that such control surfaces seemed practical for modern aircraft. This has opened the door to a new class of aircraft that have the ability to change shape or morph, which are being investigated due to the potential to have a single platform serve multiple mission objectives, as well as improve performance characteristics. While the majority of existing research for morphing aircraft has focused on fixedwing aircraft, rotary-wing aircraft have begun to receive more attention. The purpose of this body of work is to investigate the current state of morphing actuation technology for rotorcraft and improve upon it. Specifically, this work looks at two types of morphing: Pneumatic Artificial Muscle (PAM) actuated trailing edge flaps and conformal variable diameter morphing. First, active camber changes through the use of PAM powered trailing edge flaps were investigated due to the potential for reductions in power requirements and vibration/noise levels. A PAM based antagonistic actuation system was developed utilizing a novel combination of mechanism geometry and PAM bias contraction optimization to overcome the natural extension stiffening characteristics of PAMs. In open-loop bench-top testing against a "worst-case" constant torsional loading, the system demonstrated actuation authority suitable for both primary control and vibration/noise reduction. Additionally, closed-loop test data indicated that the system was capable of tracking complex waveforms consistent with those needed for rotorcraft control. This system demonstrated performance on-par with the state of the art pneumatic trailing edge flap actuators, yet with a much smaller footprint and impact on the rotor-blade. The second morphing system developed in

  3. Biologically inspired technologies in NASA's morphing project

    Science.gov (United States)

    McGowan, Anna-Maria R.; Cox, David E.; Lazos, Barry S.; Waszak, Martin R.; Raney, David L.; Siochi, Emilie J.; Pao, S. Paul

    2003-07-01

    For centuries, biology has provided fertile ground for hypothesis, discovery, and inspiration. Time-tested methods used in nature are being used as a basis for several research studies conducted at the NASA Langley Research Center as a part of Morphing Project, which develops and assesses breakthrough vehicle technologies. These studies range from low drag airfoil design guided by marine and avian morphologies to soaring techniques inspired by birds and the study of small flexible wing vehicles. Biology often suggests unconventional yet effective approaches such as non-planar wings, dynamic soaring, exploiting aeroelastic effects, collaborative control, flapping, and fibrous active materials. These approaches and other novel technologies for future flight vehicles are being studied in NASA's Morphing Project. This paper will discuss recent findings in the aeronautics-based, biologically-inspired research in the project.

  4. Special Issue: Adaptive/Smart Structures and Multifunctional Materials with Application to Morphing Aircraft

    Directory of Open Access Journals (Sweden)

    Rafic Ajaj

    2014-12-01

    Full Text Available Recent advances in smart structures and multifunctional materials have facilitated many novel aerospace technologies such as morphing aircraft. A morphing aircraft, bio-inspired by natural fliers, has gained a lot of interest as a potential technology to meet the ambitious goals of the Advisory Council for Aeronautics Research in Europe (ACARE Vision 2020 and the FlightPath 2050 documents. A morphing aircraft continuously adjusts its wing geometry to enhance flight performance, control authority, and multi-mission capability.[...

  5. Induction of resistance by silicon in wheat plants to alate and apterous morphs of Sitobion avenae (Hemiptera: Aphididae).

    Science.gov (United States)

    Dias, P A S; Sampaio, M V; Rodrigues, M P; Korndörfer, A P; Oliveira, R S; Ferreira, S E; Korndörfer, G H

    2014-08-01

    Despite the knowledge about the effects of silicon augmenting antibiosis and nonpreference of plants by apterous aphids, few studies exist on such effects with alate aphids. This study evaluated the effects of silicon fertilization on the biology of alate and apterous morphs of Sitobion avenae (F.) (Hemiptera: Aphididae), and the effect on nonpreference by S. avenae alates for wheat plants with or without silicon fertilization. A method for rearing aphids on detached leaves was evaluated comparing the biology of apterous aphids reared on wheat leaf sections and on whole plants with and without silicon fertilization. Because the use of detached leaves was a reliable method, the effect of silicon fertilization on the biology of apterous and alate S. avenae was assessed using wheat leaf sections. Biological data of aphids were used to calculate a fertility life table. Finally, the effect of silicon fertilization on the nonpreference of alate aphids was carried out for both vegetative and reproductive phases of wheat. Thirty alate aphids were released in the center of a cage, and the number of aphids per whole plant with or without silicon fertilization was observed. Silicon fertilization induced antibiosis resistance in wheat plants to apterous morphs as shown by reduced fecundity, reproductive period, longevity, intrinsic rate of increase, and net reproductive rate; however, alates were unaffected. Plants that received silicon fertilization had fewer alate aphids in both the vegetative and reproductive phases. Thus, silicon fertilization can reduce colonization by alates, enhancing nonpreference resistance, and population growth of apterous S. avenae in wheat plants.

  6. Investigation of the optimal elastic and weight properties of passive morphing skins for camber-morphing applications

    International Nuclear Information System (INIS)

    Previtali, Francesco; Arrieta, Andres F; Ermanni, Paolo

    2016-01-01

    The aerodynamic performance of wing structures is directly related to their external geometry. The idea of seamless shape adaptation of the wing geometry (or morphing) has emerged to provide the capability of operating optimally in a wide range of conditions. Of particular importance to realize the potential of morphing is the ability of the wing skin to conform to the different geometrical contours. Several concepts for morphing skins have been presented to address this design challenge, each presenting peculiar strengths and weaknesses depending on the chosen combination of material and structural arrangement. This paper investigates the generic structural properties of a passive morphing skin design to allow for optimal shape adaptation through cambering. The properties of the morphing skin are included among the design variables to identify their optimal value; multi-objective optimizations are used to obtain parametric results. The results indicate the need for a high anisotropy, both between membrane and bending properties and between the skin’s principal directions. The impact of the skin weight on the wing design is also shown. (paper)

  7. Morphing unmanned aerial vehicles

    International Nuclear Information System (INIS)

    Gomez, Juan Carlos; Garcia, Ephrahim

    2011-01-01

    Research on aircraft morphing has exploded in recent years. The motivation and driving force behind this has been to find new and novel ways to increase the capabilities of aircraft. Materials advancements have helped to increase possibilities with respect to actuation and, hence, a diversity of concepts and unimagined capabilities. The expanded role of unmanned aerial vehicles (UAVs) has provided an ideal platform for exploring these emergent morphing concepts since at this scale a greater amount of risk can be taken, as well as having more manageable fabrication and cost requirements. This review focuses on presenting the role UAVs have in morphing research by giving an overview of the UAV morphing concepts, designs, and technologies described in the literature. A presentation of quantitative information as well as a discussion of technical issues is given where possible to begin gaining some insight into the overall assessment and performance of these technologies. (topical review)

  8. Physiological trade-off between cellular immunity and flight capability in the wing-dimorphic cricket, Gryllus firmus

    Science.gov (United States)

    The sand cricket, Gryllus firmus, is a wing-dimorphic species with long-wing (LW) and short wing (LW) morphs. The LW forms have very well developed wings and flight muscles and their SW counterparts have reduced wings and flight muscles, coupled with greater resource allocations to reproduction. Thi...

  9. De novo transcriptome assembly from fat body and flight muscles transcripts to identify morph-specific gene expression profiles in Gryllus firmus.

    Directory of Open Access Journals (Sweden)

    Neetha Nanoth Vellichirammal

    Full Text Available Wing polymorphism is a powerful model for examining many aspects of adaptation. The wing dimorphic cricket species, Gryllus firmus, consists of a long-winged morph with functional flight muscles that is capable of flight, and two flightless morphs. One (obligately flightless morph emerges as an adult with vestigial wings and vestigial flight muscles. The other (plastic flightless morph emerges with fully-developed wings but later in adulthood histolyzes its flight muscles. Importantly both flightless morphs have substantially increased reproductive output relative to the flight-capable morph. Much is known about the physiological and biochemical differences between the morphs with respect to adaptations for flight versus reproduction. In contrast, little is known about the molecular genetic basis of these morph-specific adaptations. To address this issue, we assembled a de novo transcriptome of G. firmus using 141.5 million Illumina reads generated from flight muscles and fat body, two organs that play key roles in flight and reproduction. We used the resulting 34,411 transcripts as a reference transcriptome for differential gene expression analyses. A comparison of gene expression profiles from functional flight muscles in the flight-capable morph versus histolyzed flight muscles in the plastic flight incapable morph identified a suite of genes involved in respiration that were highly expressed in pink (functional flight muscles and genes involved in proteolysis highly expressed in the white (histolyzed flight muscles. A comparison of fat body transcripts from the obligately flightless versus the flight-capable morphs revealed differential expression of genes involved in triglyceride biosynthesis, lipid transport, immune function and reproduction. These data provide a valuable resource for future molecular genetics research in this and related species and provide insight on the role of gene expression in morph-specific adaptations for flight

  10. Morphing banner advertising

    NARCIS (Netherlands)

    G.L. Urban (Glen); G. Liberali (Gui); E. MacDonald (Erin); R. Bordley (Robert); J. Hauser (J.)

    2014-01-01

    textabstractResearchers and practitioners devote substantial effort to targeting banner advertisements to consumers, but they focus less effort on how to communicate with consumers once targeted. Morphing enables a website to learn, automatically and near optimally, which banner advertisements to

  11. Design, Development and Testing of Shape Shifting Wing Model

    Directory of Open Access Journals (Sweden)

    Dean Ninian

    2017-11-01

    Full Text Available The design and development of morphing (shape shifting aircraft wings—an innovative technology that has the potential to increase the aerodynamic efficiency and reduce noise signatures of aircrafts—was carried out. This research was focused on reducing lift-induced drag at the flaps of the aerofoil and to improve the design to achieve the optimum aerodynamic efficiency. Simulation revealed a 10.8% coefficient of lift increase for the initial morphing wing and 15.4% for the optimized morphing wing as compared to conventional wing design. At angles of attack of 0, 5, 10 and 15 degrees, the optimized wing has an increase in lift-to-drag ratio of 18.3%, 10.5%, 10.6% and 4% respectively when compared with the conventional wing. Simulations also showed that there is a significant improvement on pressure distribution over the lower surface of the morphing wing aerofoil. The increase in flow smoothness and reduction in vortex size reduced pressure drag along the trailing edge of the wing as a result an increase in pressure on the lower surface was experienced. A morphing wing reduced the size of the vortices and therefore the noise levels measured were reduced by up to 50%.

  12. MORPH17 Aarhus, Denmark

    Directory of Open Access Journals (Sweden)

    Cara S. Hirst

    2017-11-01

    Full Text Available MORPH17 was hosted by the Department of Archaeology and Heritage Studies, Aarhus University. The two-day conference consisted of a day of workshops on the 4th of May followed by podium presentations and a poster session on the 5th. Presentations discussed a range of studies which utilised 2D and 3D Geometric Morphometric (GMM methods to answer a series of archaeological questions. Conferences delegates also had access to the new Moesgaard Museum.

  13. Interplant movement and spatial distribution of alate and apterous morphs of Nasonovia ribisnigri (Homoptera: Aphididae) on lettuce.

    Science.gov (United States)

    Diaz, B M; Barrios, L; Fereres, A

    2012-08-01

    Knowledge on colonization modes and interplant movement of Nasonovia ribisnigri can contribute to the development of optimal control of this pest. The aim of this study was to determine the spatio-temporal distribution and the mode of spread between adult morphs of Nasonovia ribisnigri, comparing spring and autumn lettuce protected crops. The spatial and temporal pattern was analyzed using the spatial analysis by distance indices (SADIE) methodology and other related displacement indices. The population size of N. ribisnigri was greater in the autumn than in the spring growing seasons due to milder temperatures. The percentage of plants colonized by aphids was higher in spring than in autumn, showing the great dispersal potential of this aphid species independent of their population size. Differential propensity for initial displacement from the central plant was observed between adult morphs in spring, resulting in a greater ability of apterous than alate aphids to spread far away from the source plant. In autumn, both adult morphs showed an initial reduced displacement; however, the number of plants infested (≈20%) with at least one aphid at this initial time (seven days) was similar for both adult morphs and both growing seasons. Analysis of the spatial pattern of both adult morphs revealed a predominantly random distribution for both spring and autumn trials. This pattern was achieved by a prevalent random movement over the area (γ≈0.5). These results highlight the ability of the apterous N. ribisnigri to spread within greenhouse lettuce crops early in the spring, suggesting that detection of the pest by deep visual inspection is required after lettuce emergence.

  14. Aphids, predators and parasitoids.

    Science.gov (United States)

    Wadhams, L J; Birkett, M A; Powell, W; Woodcock, C M

    1999-01-01

    A number of studies have demonstrated the role of herbivore-induced release of plant volatiles in mediating foraging behaviour of aphid parasitoids, particularly with the parasitoid Aphidius ervi, its aphid host Acyrthosiphon pisum and the aphid food plant Vicia faba. These studies have shown that feeding by the aphid alters the composition of volatiles released by the plant and that these compounds act as synomones for the foraging parasitoid. Of particular interest is the species-specificity of the herbivore-induced synomones associated with different aphids feeding on V. faba. Aphids employ various pheromones that mediate behaviour, particularly mating and alarm responses. These pheromones play important roles in reproduction and defence against predation and parasitism. Many species of aphids reproduce sexually on their primary hosts during the autumn and the sexual females produce a pheromone that attracts males. The sex pheromones for a number of aphid species have been identified and laboratory and field studies have shown that synthetic material can act as a kairomone in attracting predators and parasitoids. The aphid alarm pheromone is released from the cornicles of aphids when they are attacked by predators or parasitoids. The activity of the main alarm pheromone component, (E)-beta-farnesene, is inhibited by the related sesquiterpene hydrocarbon beta-caryophyllene, which is reported to attract the lacewing Chrysoperla carnea. In addition, electrophysiological studies have shown that the seven-spot ladybird, Coccinella septempunctata, possesses specific olfactory receptors for (E)-beta-farnesene and beta-caryophyllene. Laboratory studies show these compounds to have behavioural activity with C. septempunctata, suggesting that they may be involved in prey location.

  15. Macrosiphoniella remaudierei, a new species of aphid on Helichrysum in Iran (Hemiptera, Aphididae

    Directory of Open Access Journals (Sweden)

    Sebastiano Barbagallo

    2017-01-01

    Full Text Available A new species of aphid, belonging to the genus Macrosiphoniella Del Guercio, 1911, is described using three samples collected in Iran on Helichrysum armenium (Asteraceae, Inuleae by the late Prof. G. Remaudière. Both apterous and alate viviparous females of the new taxon, M. remaudierei sp. n., are described and compared to corresponding morphs of the closely allied M. aetnensis and to other congeneric aphid species on Helichrysum in the Palaearctic region. Type specimens are now stored in the Muséum national d’Histoire naturelle in Paris.

  16. Planform, aero-structural, and flight control optimization for tailless morphing aircraft

    Science.gov (United States)

    Molinari, Giulio; Arrieta, Andres F.; Ermanni, Paolo

    2015-04-01

    Tailless airplanes with swept wings rely on variations of the spanwise lift distribution to provide controllability in roll, pitch and yaw. Conventionally, this is achieved utilizing multiple control surfaces, such as elevons, on the wing trailing edge. As every flight condition requires different control moments (e.g. to provide pitching moment equilibrium), these surfaces are practically permanently displaced. Due to their nature, causing discontinuities, corners and gaps, they bear aerodynamic penalties, mostly in terms of shape drag. Shape adaptation, by means of chordwise morphing, has the potential of varying the lift of a wing section by deforming its profile in a way that minimizes the resulting drag. Furthermore, as the shape can be varied differently along the wingspan, the lift distribution can be tailored to each specific flight condition. For this reason, tailless aircraft appear as a prime choice to apply morphing techniques, as the attainable benefits are potentially significant. In this work, we present a methodology to determine the optimal planform, profile shape, and morphing structure for a tailless aircraft. The employed morphing concept is based on a distributed compliance structure, actuated by Macro Fiber Composite (MFC) piezoelectric elements. The multidisciplinary optimization is performed considering the static and dynamic aeroelastic behavior of the resulting structure. The goal is the maximization of the aerodynamic efficiency while guaranteeing the controllability of the plane, by means of morphing, in a set of flight conditions.

  17. Evaluation of bio-inspired morphing concepts with regard to aircraft dynamics and performance

    Science.gov (United States)

    Wickenheiser, Adam M.; Garcia, Ephrahim; Waszak, Martin

    2004-07-01

    This paper will discuss the application of various bio-inspired morphing concepts to unmanned aerial vehicle (UAV) designs. Several analysis tools will be introduced to calculate the aerodynamic benefits, dynamic response, and mission-level benefits of morphing shape changes. Empirical relations are employed to calculate the effects of various geometry changes on the aerodynamics of the vehicle. A six-degree-of-freedom simulation will evaluate the stability and dynamic response of each vehicle configuration as well as "snapshots" of the morphing change. Subsequently, an aircraft performance analysis will be conducted for various shape configurations. Specifically, the performance of a bio-inspired wing is compared to conventional designs. The aircraft dynamic improvements that morphing technologies introduce will be discussed.

  18. The relationship between molecular variation and variation in the wing shape of three aphid parasitoid species. Aphidius uzbekistanicus Luzhetzki, Aphidius rhopalosiphi De Stefani Perez and Aphidius avenaphis (Fitch) (Hymenoptera: Braconidae: Aphidiinae)

    Czech Academy of Sciences Publication Activity Database

    Tomanović, Ž.; Kos, K.; Petrović, A.; Starý, Petr; Kavallieratos, N. G.; Žikić, V.; Jakše, J.; Trdan, S.; Ivanović, A.

    2013-01-01

    Roč. 252, č. 1 (2013), s. 41-47 ISSN 0044-5231 Grant - others:The Ministry of Science and Technological Development of the Republic of Serbia(RS) 43001; Slovenian Research Agency(SI) P4-0013 Institutional research plan: CEZ:AV0Z50070508 Keywords : ceral aphid parasitoid * Aphidius variation * mitochondrial COI gene Subject RIV: EH - Ecology, Behaviour Impact factor: 1.821, year: 2013 http://www.sciencedirect.com/science/article/pii/S0044523112000162

  19. Skin design studies for variable camber morphing airfoils

    International Nuclear Information System (INIS)

    Gandhi, Farhan; Anusonti-Inthra, Phuriwat

    2008-01-01

    This paper identifies the desirable attributes of a flexible skin of a morphing wing. The study is conducted using airfoil camber morphing as an example. The ideal flex-skin would be highly anisotropic, having a low in-plane axial stiffness but a high out-of-plane flexural stiffness. Reduced skin axial stiffness allows morphing at low actuation cost. However, for some substructure and actuation designs, a lower limit on the skin's in-plane axial stiffness may be required to prevent unacceptable global camber deformation under aerodynamic loads. High flexural stiffness prevents local deformation of skin sections between supports due to aerodynamic pressure loads, and avoids buckling of skin sections under compression as the airfoil cambers under actuation force. For the camber morphing application the strain levels in the flex-skin are not expected to exceed around 2%. If the axial stiffness of the flex-skin is reduced significantly, it may be necessary to consider aerodynamic stiffness (negligible vis-à-vis structural stiffness for classical airfoils) to accurately calculate deformation under loading. The approach followed in the study can be used to identify specifications for the skin and then reverse engineer and design highly anisotropic composite skins that meet the specifications

  20. Wing shape variation associated with mimicry in butterflies.

    Science.gov (United States)

    Jones, Robert T; Le Poul, Yann; Whibley, Annabel C; Mérot, Claire; ffrench-Constant, Richard H; Joron, Mathieu

    2013-08-01

    Mimetic resemblance in unpalatable butterflies has been studied by evolutionary biologists for over a century, but has largely focused on the convergence in wing color patterns. In Heliconius numata, discrete color-pattern morphs closely resemble comimics in the distantly related genus Melinaea. We examine the possibility that the shape of the butterfly wing also shows adaptive convergence. First, simple measures of forewing dimensions were taken of individuals in a cross between H. numata morphs, and showed quantitative differences between two of the segregating morphs, f. elegans and f. silvana. Second, landmark-based geometric morphometric and elliptical Fourier outline analyses were used to more fully characterize these shape differences. Extension of these techniques to specimens from natural populations suggested that, although many of the coexisting morphs could not be discriminated by shape, the differences we identified between f. elegans and f. silvana hold in the wild. Interestingly, despite extensive overlap, the shape variation between these two morphs is paralleled in their respective Melinaea comimics. Our study therefore suggests that wing-shape variation is associated with mimetic resemblance, and raises the intriguing possibility that the supergene responsible for controlling the major switch in color pattern between morphs also contributes to wing shape differences in H. numata. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

  1. Design optimization of deployable wings

    Science.gov (United States)

    Gaddam, Pradeep

    Morphing technology is an important aspect of UAV design, particularly in regards to deployable systems. The design of such system has an important impact on the vehicle's performance. The primary focus of the present research work was to determine the most optimum deployable wing design from 3 competing designs and develop one of the deployable wing designs to test in the research facility. A Matlab code was developed to optimize 3 deployable wing concepts inflatable, inflatable telescopic and rigid-folding wings based on a sequential optimization strategy. The constraints that were part of the code include the packaging constraints during its stowed state, fixed length of the deployed section and the minimum L/D constraint. This code resulted in determining the optimum weight of all the 3 designs, the most optimum weight design is the inflatable wing design. This is a result of the flexible skin material and also due to no rigid parts in the deployed wing section. Another goal of the research involved developing an inflatable telescopic wing. The prototype was tested in a wind tunnel, while the actual wing was tested in the altitude chamber to determine the deployment speed, input pressure, analyze and predict the deployment sequence and behavior of the wing at such high wind speeds and altitudes ranging from 60,000 ft to 90,000 ft. Results from these tests allowed us to conclude the deployment sequence of the telescopic wing followed from the root to the tip section. The results were used to analyze the deployment time of the wing. As expected the deployment time decreased with an increase in input pressure. The results also show us that as the altitude increases, the deployment speed of the wing also increased. This was demonstrated when the wing was tested at a maximum altitude pressure of 90,000ft, well above the design altitude of 60,000ft.

  2. Morphing flight control surface for advanced flight performance

    Science.gov (United States)

    Detrick, Matt; Kwak, Seung-Keon; Yoon, Hwan-Sik

    2006-03-01

    A novel Morphing Flight Control Surface (MFCS) system has been developed. The distinction of this research effort is that the SenAnTech team has incorporated our innovative Highly Deformable Mechanism (HDM) into our MFCS. The feasibility of this novel technology for deformable wing structures, such as airfoil shaping, warping or twisting with a flexure-based high displacement PZT actuator has been demonstrated via computational simulations such as Finite Element Analysis (FEA) and Computational Fluid Dynamics (CFD). CFD was implemented to verify the accuracy of the complex potential flow theory for this application. Then, complex potential flow theory, kinematics, geometry, and static force analysis were incorporated into a multidisciplinary GUI simulation tool. This tool has been used to aid the design of the MFCS. The results show that we can achieve up to five degrees of wing twisting with our proposed system, while using minimal volume within the wing and adding little weight.

  3. The Aircraft Morphing Program

    Science.gov (United States)

    Wlezien, R. W.; Horner, G. C.; McGowan, A. R.; Padula, S. L.; Scott, M. A.; Silcox, R. J.; Simpson, J. O.

    1998-01-01

    In the last decade smart technologies have become enablers that cut across traditional boundaries in materials science and engineering. Here we define smart to mean embedded actuation, sensing, and control logic in a tightly coupled feedback loop. While multiple successes have been achieved in the laboratory, we have yet to see the general applicability of smart devices to real aircraft systems. The NASA Aircraft Morphing program is an attempt to couple research across a wide range of disciplines to integrate smart technologies into high payoff aircraft applications. The program bridges research in seven individual disciplines and combines the effort into activities in three primary program thrusts. System studies are used to assess the highest- payoff program objectives, and specific research activities are defined to address the technologies required for development of smart aircraft systems. In this paper we address the overall program goals and programmatic structure, and discuss the challenges associated with bringing the technologies to fruition.

  4. Aphid Infestation Increases Fusarium langsethiae and T-2 and HT-2 Mycotoxins in Wheat.

    Science.gov (United States)

    Drakulic, Jassy; Ajigboye, Olubukola; Swarup, Ranjan; Bruce, Toby; Ray, Rumiana V

    2016-11-15

    Fusarium langsethiae is a fungal pathogen of cereal crops that is an increasing problem in northern Europe, but much of its epidemiology is poorly understood. The species produces the mycotoxins T-2 and HT-2, which are highly toxic. It was hypothesized that grain aphids, Sitobion avenae, may transmit F. langsethiae inoculum between wheat plants, and a series of transmission experiments and volatile chemical analyses was performed to test this. Manual translocation of aphids from inoculated to uninfected hosts resulted in pathogen DNA accumulation in hosts. However, the free movement of wingless aphids from infected to healthy plants did not. The addition of winged aphids reared on F. langsethiae-inoculated wheat seedlings to wheat plants also did not achieve successful pathogen transfer. While our data suggested that aphid transmission of the pathogen was not very efficient, we observed an increase in disease when aphids were present. After seedling inoculation, an increase in pathogen DNA accumulation in seedling leaves was observed upon treatment with aphids. Furthermore, the presence of aphids on wheat plants with F. langsethiae-inoculated ears not only led to a rise in the amount of F. langsethiae DNA in infected grain but also to an increase in the concentrations of T-2 and HT-2 toxins, with more than 3-fold higher toxin levels than diseased plants without aphids. This work highlights that aphids increase the susceptibility of wheat host plants to F. langsethiae and that aphid infestation is a risk factor for accumulating increased levels of T-2 and HT-2 in wheat products. Fusarium langsethiae is shown here to cause increased contamination levels of grain with toxins produced by fungus when aphids share the host plant. This effect has also recently been demonstrated with Fusarium graminearum, yet the two fungal species show stark differences in their effect on aphid populations. In both cases, aphids improve the ability of the pathogens to cause and initiate

  5. Preliminary aeroelastic assessment of a large aeroplane equipped with a camber-morphing aileron

    Science.gov (United States)

    Pecora, Rosario; Amoroso, Francesco; Palumbo, Rita; Arena, Maurizio; Amendola, Gianluca; Dimino, Ignazio

    2017-04-01

    The development of adaptive morphing wings has been individuated as one of the crucial topics in the greening of the next generation air transport. Research programs have been lunched and are still running worldwide to exploit the potentials of morphing concepts in the optimization of aircraft efficiency and in the consequent reduction of fuel burn. In the framework of CRIAQ MDO 505, a joint Canadian and Italian research project, an innovative camber morphing architecture was proposed for the aileron of a reference civil transportation aircraft; aileron shape adaptation was conceived to increase roll control effectiveness as well as to maximize overall wing efficiency along a typical flight mission. Implemented structural solutions and embedded systems were duly validated by means of ground tests carried out on a true scale prototype. Relying upon the experimental modes of the device in free-free conditions, a rational analysis was carried out in order to investigate the impacts of the morphing aileron on the aeroelastic stability of the reference aircraft. Flutter analyses were performed in compliance with EASA CS-25 airworthiness requirements and referring -at first- to nominal aileron functioning. In this way, safety values for aileron control harmonic and degree of mass-balance were defined to avoid instabilities within the flight envelope. Trade-off analyses were finally addressed to justify the robustness of the adopted massbalancing as well as the persistence of the flutter clearance in case of relevant failures/malfunctions of the morphing system components.

  6. Host Plant Volatiles and the Sexual Reproduction of the Potato Aphid, Macrosiphum euphorbiae

    Directory of Open Access Journals (Sweden)

    Jessica Hurley

    2014-10-01

    Full Text Available In late summer, heteroecious aphids, such as the potato aphid, Macrosiphum euphorbiae, move from their secondary summer host plants to primary host plants, where the sexual oviparae mate and lay diapausing eggs. We tested the hypothesis that volatiles of the primary host, Rosa rugosa, would attract the gynoparae, the parthenogenetic alate morph that produce oviparae, as well as the alate males foraging for suitable mates. In wind tunnel assays, both gynoparae and males oriented towards and reached rose cuttings significantly more often than other odour sources, including potato, a major secondary host. The response of males was as high to rose cuttings alone as to potato with a calling virgin oviparous female. These findings are discussed within the seasonal ecology of host alternating aphids.

  7. Design of a shape-memory alloy actuated macro-scale morphing aircraft mechanism

    Science.gov (United States)

    Manzo, Justin; Garcia, Ephrahim; Wickenheiser, Adam; Horner, Garnett C.

    2005-05-01

    As more alternative, lightweight actuators have become available, the conventional fixed-wing configuration seen on modern aircraft is under investigation for efficiency on a broad scale. If an aircraft could be designed with multiple functional equilibria of drastically varying aerodynamic parameters, one craft capable of 'morphing' its shape could be used to replace two or three designed with particular intentions. One proposed shape for large-scale (geometry change on the same order of magnitude as wingspan) morphing is the Hyper-Elliptical Cambered Span (HECS) wing, designed at NASA Langley to be implemented on an unmanned aerial vehicle (UAV). Proposed mechanisms to accomplish the spanwise curvature (in the y-z plane of the craft) that allow near-continuous bending of the wing are narrowed to a tendon-based DC motor actuated system, and a shape memory alloy-based (SMA) mechanism. At Cornell, simulations and wind tunnel experiments assess the validity of the HECS wing as a potential shape for a blended-wing body craft with the potential to effectively serve the needs of two conventional UAVs, and analyze the energetics of actuation associated with a morphing maneuver accomplished with both a DC motor and SMA wire.

  8. Virtual sensor for failure detection, identification and recovery in the transition phase of a morphing aircraft.

    Science.gov (United States)

    Heredia, Guillermo; Ollero, Aníbal

    2010-01-01

    The Helicopter Adaptive Aircraft (HADA) is a morphing aircraft which is able to take-off as a helicopter and, when in forward flight, unfold the wings that are hidden under the fuselage, and transfer the power from the main rotor to a propeller, thus morphing from a helicopter to an airplane. In this process, the reliable folding and unfolding of the wings is critical, since a failure may determine the ability to perform a mission, and may even be catastrophic. This paper proposes a virtual sensor based Fault Detection, Identification and Recovery (FDIR) system to increase the reliability of the HADA aircraft. The virtual sensor is able to capture the nonlinear interaction between the folding/unfolding wings aerodynamics and the HADA airframe using the navigation sensor measurements. The proposed FDIR system has been validated using a simulation model of the HADA aircraft, which includes real phenomena as sensor noise and sampling characteristics and turbulence and wind perturbations.

  9. Combining spanwise morphing, inline motion and model based optimization for force magnitude and direction control

    Science.gov (United States)

    Scheller, Johannes; Braza, Marianna; Triantafyllou, Michael

    2016-11-01

    Bats and other animals rapidly change their wingspan in order to control the aerodynamic forces. A NACA0013 type airfoil with dynamically changing span is proposed as a simple model to experimentally study these biomimetic morphing wings. Combining this large-scale morphing with inline motion allows to control both force magnitude and direction. Force measurements are conducted in order to analyze the impact of the 4 degree of freedom flapping motion on the flow. A blade-element theory augmented unsteady aerodynamic model is then used to derive optimal flapping trajectories.

  10. Arabidopsis thaliana—Aphid Interaction

    Science.gov (United States)

    Louis, Joe; Singh, Vijay; Shah, Jyoti

    2012-01-01

    Aphids are important pests of plants that use their stylets to tap into the sieve elements to consume phloem sap. Besides the removal of photosynthates, aphid infestation also alters source-sink patterns. Most aphids also vector viral diseases. In this chapter, we will summarize on recent significant findings in plant-aphid interaction, and how studies involving Arabidopsis thaliana and Myzus persicae (Sülzer), more commonly known as the green peach aphid (GPA), are beginning to provide important insights into the molecular basis of plant defense and susceptibility to aphids. The recent demonstration that expression of dsRNA in Arabidopsis can be used to silence expression of genes in GPA has further expanded the utility of Arabidopsis for evaluating the contribution of the aphid genome-encoded proteins to this interaction. PMID:22666177

  11. Variable stiffness corrugated composite structure with shape memory polymer for morphing skin applications

    Science.gov (United States)

    Gong, Xiaobo; Liu, Liwu; Scarpa, Fabrizio; Leng, Jinsong; Liu, Yanju

    2017-03-01

    This work presents a variable stiffness corrugated structure based on a shape memory polymer (SMP) composite with corrugated laminates as reinforcement that shows smooth aerodynamic surface, extreme mechanical anisotropy and variable stiffness for potential morphing skin applications. The smart composite corrugated structure shows a low in-plane stiffness to minimize the actuation energy, but also possess high out-of-plane stiffness to transfer the aerodynamic pressure load. The skin provides an external smooth aerodynamic surface because of the one-sided filling with the SMP. Due to variable stiffness of the shape memory polymer the morphing skin exhibits a variable stiffness with a change of temperature, which can help the skin adjust its stiffness according different service environments and also lock the temporary shape without external force. Analytical models related to the transverse and bending stiffness are derived and validated using finite element techniques. The stiffness of the morphing skin is further investigated by performing a parametric analysis against the geometry of the corrugation and various sets of SMP fillers. The theoretical and numerical models show a good agreement and demonstrate the potential of this morphing skin concept for morphing aircraft applications. We also perform a feasibility study of the use of this morphing skin in a variable camber morphing wing baseline. The results show that the morphing skin concept exhibits sufficient bending stiffness to withstand the aerodynamic load at low speed (less than 0.3 Ma), while demonstrating a large transverse stiffness variation (up to 191 times) that helps to create a maximum mechanical efficiency of the structure under varying external conditions.

  12. A Novel SMA-based Concept for Airfoil Structural Morphing

    Science.gov (United States)

    Barbarino, S.; Pecora, R.; Lecce, L.; Concilio, A.; Ameduri, S.; Calvi, E.

    2009-08-01

    The adaptive structures concept is of great interest in the aerospace field because of the several benefits which can be accomplished in the fields including noise reduction, load alleviation, weight reduction, etc., at a level in which they can be considered as compulsory in the design of future aircraft. Improvements in terms of the aerodynamic efficiency, aeroelastic behavior, stability, and manoeuvrability performance have already been proved through many international studies in the past. In the family of the Smart Materials, Shape Memory Alloys (SMA) seem to be a suitable solution for many static applications. Their high structural integrability in conjunction with actuation capabilities and a favorable performance per weight ratio, allows the development of original architectures. In this study, a morphing wing trailing edge concept is presented; morphing ability was introduced with the aim of replacing a conventional flap device. A compliant rib structure was designed, based on SMA actuators exhibiting structural potential (bearing external aerodynamic loads). Numerical results, achieved through a FE approach, are presented in terms of trailing edge induced displacement and morphed shape.

  13. New genus and species of the extinct aphid family Szelegiewicziidae and their implications for aphid evolution.

    Science.gov (United States)

    Wegierek, Piotr; Żyła, Dagmara; Homan, Agnieszka; Cai, Chenyang; Huang, Diying

    2017-10-24

    Recently, we are witnessing an increased appreciation for the importance of the fossil record in phylogenetics and testing various evolutionary hypotheses. However, this approach brings many challenges, especially for such a complex group as aphids and requires a thorough morphological analysis of the extinct groups. The extinct aphid family Szelegiewicziidae is supposed to be one of the oviparous lineages in aphid evolution. New material from the rock fossil deposits of Shar Teg (Upper Jurassic of Mongolia), Baissa (Lower Cretaceous of Siberia-Russia), and Burmese amber (Upper Cretaceous of Myanmar) allowed us to undertake a more detailed examination of the morphological features and carry out an analysis of the taxonomical composition and evolution of the family. This led us to the conclusion that evolution of the body plan and wing structure was similar in different, often not closely related groups, probably as a result of convergence. Additionally, we present a description of a new genus and two species (Tinaphis mongolica Żyła &Wegierek, sp. nov., and Feroorbis burmensis Wegierek & Huang, gen. et sp. nov.) that belong to this family.

  14. New genus and species of the extinct aphid family Szelegiewicziidae and their implications for aphid evolution

    Science.gov (United States)

    Wegierek, Piotr; Żyła, Dagmara; Homan, Agnieszka; Cai, Chenyang; Huang, Diying

    2017-12-01

    Recently, we are witnessing an increased appreciation for the importance of the fossil record in phylogenetics and testing various evolutionary hypotheses. However, this approach brings many challenges, especially for such a complex group as aphids and requires a thorough morphological analysis of the extinct groups. The extinct aphid family Szelegiewicziidae is supposed to be one of the oviparous lineages in aphid evolution. New material from the rock fossil deposits of Shar Teg (Upper Jurassic of Mongolia), Baissa (Lower Cretaceous of Siberia-Russia), and Burmese amber (Upper Cretaceous of Myanmar) allowed us to undertake a more detailed examination of the morphological features and carry out an analysis of the taxonomical composition and evolution of the family. This led us to the conclusion that evolution of the body plan and wing structure was similar in different, often not closely related groups, probably as a result of convergence. Additionally, we present a description of a new genus and two species ( Tinaphis mongolica Żyła &Wegierek, sp. nov., and Feroorbis burmensis Wegierek & Huang, gen. et sp. nov.) that belong to this family.

  15. Cucumber Plants Baited with Methyl Salicylate Accelerates Scymnus (Pullus) sodalis (Coleoptera: Coccinellidae) Visiting to Reduce Cotton Aphid (Hemiptera: Aphididae) Infestation.

    Science.gov (United States)

    Dong, Y J; Hwang, S Y

    2017-10-01

    The cotton aphid, Aphis gossypii (Glover) (Hemiptera: Aphididae), is a major pest of many crops worldwide and a major cucumber plant pest in Taiwan. Because cotton aphids rapidly develop insecticide resistance and because of the insecticide residue problem, a safe and sustainable method is required to replace conventional chemical control methods. Methyl salicylate (MeSA), a herbivore-induced plant volatile, has been shown to affect aphids' behavior and attract the natural enemies of aphids for reducing their population. Therefore, this study examined the direct effects of MeSA on cotton aphids' settling preference, population development, and attractiveness to natural enemies. The efficiency of using MeSA and the commercial insecticide pymetrozine for reducing the cotton aphid population in laboratory and outdoor cucumber plant pot was also examined. The results showed no difference in winged aphids' settling preference and population development between the MeSA and blank treatments. Cucumber plants infested with cotton aphids and baited with 0.1% or 10% MeSA contained significantly higher numbers of the natural enemy of cotton aphids, namely Scymnus (Pullus) sodalis (Weise) (Coleoptera: Coccinellidae), and MeSA-treated cucumber plants contained a lower number of aphids. Significantly lower cotton aphid numbers were found on cucumber plants within a 10-m range of MeSA application. In addition, fruit yield showed no difference between the MeSA and pymetrozine treatments. According to our findings, 0.1% MeSA application can replace insecticides as a cotton aphid control tool. However, large-scale experiments are necessary to confirm its efficiency and related conservation biological control strategies before further use. © The Author 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Reproduction and dispersal in an ant-associated root aphid community

    DEFF Research Database (Denmark)

    Ivens, A.B.F.; Kronauer, Daniel Jan Christoph; Pen, I.

    2012-01-01

    Clonal organisms with occasional sex are important for our general understanding of the costs and benefits that maintain sexual reproduction. Cyclically parthenogenetic aphids are highly variable in their frequency of sexual reproduction. However, studies have mostly focused on free-living aphids...... viscosity is high and winged aphids rare, consistent with infrequent horizontal transmission between ant host colonies. The absence of the primary host shrub (Pistacia) may explain the absence of sex in three of the studied species, but elm trees (Ulmus) that are primary hosts of the fourth species (T...... to L. flavus populations, so that all four root aphid species would have realistic opportunities for completing their sexual life cycle....

  17. Defocus morphing in real aperture images.

    Science.gov (United States)

    Chaudhuri, Subhasis

    2005-11-01

    A new concept called defocus morphing in real aperture images is introduced. View morphing is an existing example of shape-preserving image morphing based on the motion cue. It is proved that images can also be morphed based on the depth-related defocus cue. This illustrates that the morphing operation is not necessarily a geometric process alone; one can also perform a photometry-based morphing wherein the shape information is implicitly buried in the image intensity field. A theoretical understanding of the defocus morphing process is presented. It is shown mathematically that, given two observations of a three-dimensional scene for different camera parameter settings, we can obtain a virtual observation for any camera parameter setting through a simple nonlinear combination of these observations.

  18. Light field morphing using 2D features.

    Science.gov (United States)

    Wang, Lifeng; Lin, Stephen; Lee, Seungyong; Guo, Baining; Shum, Heung-Yeung

    2005-01-01

    We present a 2D feature-based technique for morphing 3D objects represented by light fields. Existing light field morphing methods require the user to specify corresponding 3D feature elements to guide morph computation. Since slight errors in 3D specification can lead to significant morphing artifacts, we propose a scheme based on 2D feature elements that is less sensitive to imprecise marking of features. First, 2D features are specified by the user in a number of key views in the source and target light fields. Then the two light fields are warped view by view as guided by the corresponding 2D features. Finally, the two warped light fields are blended together to yield the desired light field morph. Two key issues in light field morphing are feature specification and warping of light field rays. For feature specification, we introduce a user interface for delineating 2D features in key views of a light field, which are automatically interpolated to other views. For ray warping, we describe a 2D technique that accounts for visibility changes and present a comparison to the ideal morphing of light fields. Light field morphing based on 2D features makes it simple to incorporate previous image morphing techniques such as nonuniform blending, as well as to morph between an image and a light field.

  19. A systematic method of smooth switching LPV controllers design for a morphing aircraft

    Directory of Open Access Journals (Sweden)

    Jiang Weilai

    2015-12-01

    Full Text Available This paper is concerned with a systematic method of smooth switching linear parameter-varying (LPV controllers design for a morphing aircraft with a variable wing sweep angle. The morphing aircraft is modeled as an LPV system, whose scheduling parameter is the variation rate of the wing sweep angle. By dividing the scheduling parameter set into subsets with overlaps, output feedback controllers which consider smooth switching are designed and the controllers in overlapped subsets are interpolated from two adjacent subsets. A switching law without constraint on the average dwell time is obtained which makes the conclusion less conservative. Furthermore, a systematic algorithm is developed to improve the efficiency of the controllers design process. The parameter set is divided into the fewest subsets on the premise that the closed-loop system has a desired performance. Simulation results demonstrate the effectiveness of this approach.

  20. Silencing the expression of the salivary sheath protein causes transgenerational feeding suppression in the aphid Sitobion avenae.

    Science.gov (United States)

    Abdellatef, Eltayb; Will, Torsten; Koch, Aline; Imani, Jafargholi; Vilcinskas, Andreas; Kogel, Karl-Heinz

    2015-08-01

    Aphids produce gel saliva during feeding which forms a sheath around the stylet as it penetrates through the apoplast. The sheath is required for the sustained ingestion of phloem sap from sieve elements and is thought to form when the structural sheath protein (SHP) is cross-linked by intermolecular disulphide bridges. We investigated the possibility of controlling aphid infestation by host-induced gene silencing (HIGS) targeting shp expression in the grain aphid Sitobion avenae. When aphids were fed on transgenic barley expressing shp double-stranded RNA (shp-dsRNA), they produced significantly lower levels of shp mRNA compared to aphids feeding on wild-type plants, suggesting that the transfer of inhibitory RNA from the plant to the insect was successful. shp expression remained low when aphids were transferred from transgenic plants and fed for 1 or 2 weeks, respectively, on wild-type plants, confirming that silencing had a prolonged impact. Reduced shp expression correlated with a decline in growth, reproduction and survival rates. Remarkably, morphological and physiological aberrations such as winged adults and delayed maturation were maintained over seven aphid generations feeding on wild-type plants. Targeting shp expression therefore appears to cause strong transgenerational effects on feeding, development and survival in S. avenae, suggesting that the HIGS technology has a realistic potential for the control of aphid pests in agriculture. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  1. Design, realization and structural testing of a compliant adaptable wing

    International Nuclear Information System (INIS)

    Molinari, G; Arrieta, A F; Ermanni, P; Quack, M; Morari, M

    2015-01-01

    This paper presents the design, optimization, realization and testing of a novel wing morphing concept, based on distributed compliance structures, and actuated by piezoelectric elements. The adaptive wing features ribs with a selectively compliant inner structure, numerically optimized to achieve aerodynamically efficient shape changes while simultaneously withstanding aeroelastic loads. The static and dynamic aeroelastic behavior of the wing, and the effect of activating the actuators, is assessed by means of coupled 3D aerodynamic and structural simulations. To demonstrate the capabilities of the proposed morphing concept and optimization procedure, the wings of a model airplane are designed and manufactured according to the presented approach. The goal is to replace conventional ailerons, thus to achieve controllability in roll purely by morphing. The mechanical properties of the manufactured components are characterized experimentally, and used to create a refined and correlated finite element model. The overall stiffness, strength, and actuation capabilities are experimentally tested and successfully compared with the numerical prediction. To counteract the nonlinear hysteretic behavior of the piezoelectric actuators, a closed-loop controller is implemented, and its capability of accurately achieving the desired shape adaptation is evaluated experimentally. Using the correlated finite element model, the aeroelastic behavior of the manufactured wing is simulated, showing that the morphing concept can provide sufficient roll authority to allow controllability of the flight. The additional degrees of freedom offered by morphing can be also used to vary the plane lift coefficient, similarly to conventional flaps. The efficiency improvements offered by this technique are evaluated numerically, and compared to the performance of a rigid wing. (paper)

  2. Shape-morphing nanocomposite origami.

    Science.gov (United States)

    Andres, Christine M; Zhu, Jian; Shyu, Terry; Flynn, Connor; Kotov, Nicholas A

    2014-05-20

    Nature provides a vast array of solid materials that repeatedly and reversibly transform in shape in response to environmental variations. This property is essential, for example, for new energy-saving technologies, efficient collection of solar radiation, and thermal management. Here we report a similar shape-morphing mechanism using differential swelling of hydrophilic polyelectrolyte multilayer inkjets deposited on an LBL carbon nanotube (CNT) composite. The out-of-plane deflection can be precisely controlled, as predicted by theoretical analysis. We also demonstrate a controlled and stimuli-responsive twisting motion on a spiral-shaped LBL nanocomposite. By mimicking the motions achieved in nature, this method offers new opportunities for the design and fabrication of functional stimuli-responsive shape-morphing nanoscale and microscale structures for a variety of applications.

  3. Energy-based aeroelastic analysis of a morphing wing

    NARCIS (Netherlands)

    De Breuker, R.; Abdalla, M.; Gürdal, Z.; Lindner, D.

    2007-01-01

    Aircraft are often confronted with distinct circumstances during different parts of their mission. Ideally the aircraft should fly optimally in terms of aerodynamic performance and other criteria in each one of these mission requirements. This requires in principle as many different aircraft

  4. Analysis of composite wing structures with a morphing leading edge

    OpenAIRE

    Morishima, Ryoko

    2011-01-01

    One of the main challenges for the civil aviation industry is the reduction of its environmental impact. Over the past years, improvements in performance efficiency have been achieved by simplifying the design of the structural components and using composite materials to reduce the overall weight. These approaches however, are not sufficient to meet the current demanding requirements set for a „greener‟ aircraft. Significant changes in drag reduction and fuel consumption can be obtained by...

  5. Innovative Materials for Aircraft Morphing

    Science.gov (United States)

    Simpson, J. O.; Wise, S. A.; Bryant, R. G.; Cano, R. J.; Gates, T. S.; Hinkley, J. A.; Rogowski, R. S.; Whitley, K. S.

    1997-01-01

    Reported herein is an overview of the research being conducted within the Materials Division at NASA Langley Research Center on the development of smart material technologies for advanced airframe systems. The research is a part of the Aircraft Morphing Program which is a new six-year research program to develop smart components for self-adaptive airframe systems. The fundamental areas of materials research within the program are computational materials; advanced piezoelectric materials; advanced fiber optic sensing techniques; and fabrication of integrated composite structures. This paper presents a portion of the ongoing research in each of these areas of materials research.

  6. Experimental validation of a true-scale morphing flap for large civil aircraft applications

    Science.gov (United States)

    Pecora, R.; Amoroso, F.; Arena, M.; Noviello, M. C.; Rea, F.

    2017-04-01

    Within the framework of the JTI-Clean Sky (CS) project, and during the first phase of the Low Noise Configuration Domain of the Green Regional Aircraft - Integrated Technological Demonstration (GRA-ITD, the preliminary design and technological demonstration of a novel wing flap architecture were addressed. Research activities were carried out to substantiate the feasibility of morphing concepts enabling flap camber variation in compliance with the demanding safety requirements applicable to the next generation green regional aircraft, 130- seats with open rotor configuration. The driving motivation for the investigation on such a technology was found in the opportunity to replace a conventional double slotted flap with a single slotted camber-morphing flap assuring similar high lift performances -in terms of maximum attainable lift coefficient and stall angle- while lowering emitted noise and system complexity. Studies and tests were limited to a portion of the flap element obtained by slicing the actual flap geometry with two cutting planes distant 0.8 meters along the wing span. Further activities were then addressed in order to increase the TRL of the validated architecture within the second phase of the CS-GRA. Relying upon the already assessed concept, an innovative and more advanced flap device was designed in order to enable two different morphing modes on the basis of the A/C flight condition / flap setting: Mode1, Overall camber morphing to enhance high-lift performances during take-off and landing (flap deployed); Mode2, Tab-like morphing mode. Upwards and downwards deflection of the flap tip during cruise (flap stowed) for load control at high speed. A true-scale segment of the outer wing flap (4 meters span with a mean chord of 0.9 meters) was selected as investigation domain for the new architecture in order to duly face the challenges posed by real wing installation. Advanced and innovative solutions for the adaptive structure, actuation and control

  7. Recent Results from NASA's Morphing Project

    Science.gov (United States)

    McGowan, Anna-Maria R.; Washburn, Anthony E.; Horta, Lucas G.; Bryant, Robert G.; Cox, David E.; Siochi, Emilie J.; Padula, Sharon L.; Holloway, Nancy M.

    2002-01-01

    The NASA Morphing Project seeks to develop and assess advanced technologies and integrated component concepts to enable efficient, multi-point adaptability in air and space vehicles. In the context of the project, the word "morphing" is defined as "efficient, multi-point adaptability" and may include macro, micro, structural and/or fluidic approaches. The project includes research on smart materials, adaptive structures, micro flow control, biomimetic concepts, optimization and controls. This paper presents an updated overview of the content of the Morphing Project including highlights of recent research results.

  8. Morphing a plasmonic nanodisk into a nanotriangle.

    Science.gov (United States)

    Schmidt, Franz P; Ditlbacher, Harald; Hofer, Ferdinand; Krenn, Joachim R; Hohenester, Ulrich

    2014-08-13

    We morph a silver nanodisk into a nanotriangle by producing a series of nanoparticles with electron beam lithography. Using electron energy loss spectroscopy (EELS), we map out the plasmonic eigenmodes and trace the evolution of edge and film modes during morphing. Our results suggest that disk modes, characterized by angular order, can serve as a suitable basis for other nanoparticle geometries and are subject to resonance energy shifts and splittings, as well as to hybridization upon morphing. Similar to the linear combination of atomic orbitals (LCAO) in quantum chemistry, we introduce a linear combination of plasmonic eigenmodes to describe plasmon modes in different geometries, hereby extending the successful hybridization model of plasmonics.

  9. Perspectives on Highly Adaptive or Morphing Aircraft

    Science.gov (United States)

    McGowan, Anna-Maria R.; Vicroy, Dan D.; Busan, Ronald C.; Hahn, Andrew S.

    2009-01-01

    The ability to adapt to different flight conditions has been fundamental to aircraft design since the Wright Brothers first flight. Over a hundred years later, unconventional aircraft adaptability, often called aircraft morphing has become a topic of considerable renewed interest. In the past two decades, this interest has been largely fuelled by advancements in multi-functional or smart materials and structures. However, highly adaptive or morphing aircraft is certainly a cross-discipline challenge that stimulates a wide range of design possibilities. This paper will review some of the history of morphing aircraft including recent research programs and discuss some perspectives on this work.

  10. Design and analysis of biomimetic joints for morphing of micro air vehicles

    International Nuclear Information System (INIS)

    Grant, Daniel T; Abdulrahim, Mujahid; Lind, Rick

    2010-01-01

    Flight capability for micro air vehicles is rapidly maturing throughout the aviation community; however, mission capability has not yet matured at the same pace. Maintaining trim during a descent or in the presence of crosswinds remains challenging for fixed-wing aircraft but yet is routinely performed by birds. This paper presents an overview of designs that incorporate morphing to enhance their flight characteristics. In particular, a series of joints and structures is adopted from seagulls to alter either the dihedral or sweep of the wings and thus alter the flight characteristics. The resulting vehicles are able to trim with significantly increased angles of attack and sideslip compared to traditional fixed-wing vehicles.

  11. Aphid resistance in florist's chrysanthemum (Chrysanthemum ...

    African Journals Online (AJOL)

    ... SAE is readily toxic when ingested by the pea aphid, Acyrthosiphon pisum, and the cotton aphid, Aphis gossypii. We transformed chrysanthemum genotype 1581 by Agrobacterium tumefaciens-mediated transformation with the SAE gene under the control of the chrysanthemum RbcS promoter to induce aphid resistance.

  12. New Records of Aphid Fauna in Turkey

    OpenAIRE

    Kaygin, Azize Toper; Gorur, Gazi; Cota, Figen

    2010-01-01

    Three aphid species were identified as new records for Turkey aphid fauna from Bartin province. These species are Ceruraphis viburnicola (Gillette) (Hemiptera: Aphididae), Dysaphis apiifolia (Theobald) (Hemiptera: Aphididae) and Macrosiphum mordvilkoi Miyazaki (Hemiptera: Aphididae). These records increase the recorded aphid-fauna of Turkey to 433 species.

  13. Shape morphing Kirigami mechanical metamaterials.

    Science.gov (United States)

    Neville, Robin M; Scarpa, Fabrizio; Pirrera, Alberto

    2016-08-05

    Mechanical metamaterials exhibit unusual properties through the shape and movement of their engineered subunits. This work presents a new investigation of the Poisson's ratios of a family of cellular metamaterials based on Kirigami design principles. Kirigami is the art of cutting and folding paper to obtain 3D shapes. This technique allows us to create cellular structures with engineered cuts and folds that produce large shape and volume changes, and with extremely directional, tuneable mechanical properties. We demonstrate how to produce these structures from flat sheets of composite materials. By a combination of analytical models and numerical simulations we show how these Kirigami cellular metamaterials can change their deformation characteristics. We also demonstrate the potential of using these classes of mechanical metamaterials for shape change applications like morphing structures.

  14. Shape morphing hinged truss structures

    International Nuclear Information System (INIS)

    Sofla, A Y N; Elzey, D M; Wadley, H N G

    2009-01-01

    Truss structures are widely used for the support of structural loads in applications where minimum mass solutions are required. Their nodes are normally constructed to resist rotation to maximize their stiffness under load. A multi-link node concept has recently been proposed that permits independent rotation of tetrahedral trusses linked by such a joint. High authority shape morphing truss structures can therefore be designed by the installation of linear displacement actuators within the truss mechanisms. Examples of actuated structures with either linear or planar shapes are presented and their ability to bend, twist and undulate is demonstrated. An experimental device has been constructed using one-way shape memory wire actuators in antagonistic configurations that permit reversible actuated structures. It is shown that the actuated structure displacement response is significantly amplified by use of a mechanically magnified design

  15. NDVI to Detect Sugarcane Aphid Injury to Grain Sorghum.

    Science.gov (United States)

    Elliott, N C; Backoulou, G F; Brewer, M J; Giles, K L

    2015-06-01

    Multispectral remote sensing has potential to provide quick and inexpensive information on sugarcane aphid, Melanaphis sacchari (Zehntner), pest status in sorghum fields. We describe a study conducted to determine if injury caused by sugarcane aphid to sorghum plants in fields of grain sorghum could be detected using multispectral remote sensing from a fixed wing aircraft. A study was conducted in commercial grain sorghum fields in the Texas Gulf Coast region in June 2014. Twenty-six commercial grain sorghum fields were selected and rated for the level of injury to sorghum plants in the field caused by sugarcane aphid. Plant growth stage ranged from 5.0 (watery ripe) to 7.0 (hard dough) among fields; and plant injury rating from sugarcane aphid ranged from 1.0 (little or no injury) to 4.0 (>40% of plants displaying injury) among fields. The normalized differenced vegetation index (NDVI) is calculated from light reflectance in the red and near-infrared wavelength bands in multispectral imagery and is a common index of plant stress. High NDVI indicates low levels of stress and low NDVI indicates high stress. NDVI ranged from -0.07 to 0.26 among fields. The correlation between NDVI and plant injury rating was negative and significant, as was the correlation between NDVI and plant growth stage. The negative correlation of NDVI with injury rating indicated that plant stress increased with increasing plant injury. Reduced NDVI with increasing plant growth probably resulted from reduced photosynthetic activity in more mature plants. The correlation between plant injury rating and plant growth stage was positive and significant indicating that plant injury from sugarcane aphid increased as plants matured. The partial correlation of NDVI with plant injury rating was negative and significant indicating that NDVI decreased with increasing plant injury after adjusting for its association with plant growth stage. We demonstrated that remotely sensed imagery acquired from grain

  16. Morphological variation of Aphidius ervi Haliday (Hymenoptera: Braconidae associated with different aphid hosts

    Directory of Open Access Journals (Sweden)

    Cinthya M. Villegas

    2017-07-01

    Full Text Available Background Parasitoids are frequently used in biological control due to the fact that they are considered host specific and highly efficient at attacking their hosts. As they spend a significant part of their life cycle within their hosts, feeding habits and life history of their host can promote specialization via host-race formation (sequential radiation. The specialized host races from different hosts can vary morphologically, behaviorally and genetically. However, these variations are sometimes inconspicuous and require more powerful tools in order to detect variation such as geometric morphometrics analysis. Methods We examined Aphidius ervi, an important introduced biological control agent in Chile associated with a great number of aphid species, which are exploiting different plant hosts and habitats. Several combinations (biotypes of parasitoids with various aphid/host plant combinations were analyzed in order to obtain measures of forewing shape and size. To show the differences among defined biotypes, we chose 13 specific landmarks on each individual parasitoid wing. The analysis of allometric variation calculated in wing shape and size over centroid size (CS, revealed the allometric changes among biotypes collected from different hosts. To show all differences in shape of forewings, we made seven biotype pairs using an outline-based geometric morphometrics comparison. Results The biotype A. pis_pea (Acyrthosiphon pisum on pea was the extreme wing size in this study compared to the other analyzed biotypes. Aphid hosts have a significant influence in the morphological differentiation of the parasitoid forewing, splitting biotypes in two groups. The first group consisted of biotypes connected with Acyrthosiphon pisum on legumes, while the second group is composed of biotypes connected with aphids attacking cereals, with the exception of the R. pad_wheat (Rhopalosiphum padi on wheat biotype. There was no significant effect of plant

  17. Seasonal phenology and species composition of the aphid fauna in a northern crop production area.

    Directory of Open Access Journals (Sweden)

    Sascha M Kirchner

    Full Text Available BACKGROUND: The species diversity of aphids and seasonal timing of their flight activity can have significant impacts on crop production, as aphid species differ in their ability to transmit plant viruses and flight timing affects virus epidemiology. The aim of the study was to characterise the species composition and phenology of aphid fauna in Finland in one of the northernmost intensive crop production areas of the world (latitude 64°. METHODOLOGY/PRINCIPAL FINDINGS: Flight activity was monitored in four growing seasons (2007-010 using yellow pan traps (YPTs placed in 4-8 seed potato fields and a Rothamsted suction trap. A total of 58,528 winged aphids were obtained, identified to 83 taxa based on morphology, and 34 species were additionally characterised by DNA barcoding. Seasonal flight activity patterns analysed based on YPT catch fell into three main phenology clusters. Monoecious taxa showed early or middle-season flight activity and belonged to species living on shrubs/trees or herbaceous plants, respectively. Heteroecious taxa occurred over the entire potato growing season (ca. 90 days. Abundance of aphids followed a clear 3-year cycle based on suction trap data covering a decade. Rhopalosiphum padi occurring at the end of the potato growing season was the most abundant species. The flight activity of Aphis fabae, the main vector of Potato virus Y in the region, and Aphis gossypii peaked in the beginning of potato growing season. CONCLUSIONS/SIGNIFICANCE: Detailed information was obtained on phenology of a large number aphid species, of which many are agriculturally important pests acting as vectors of plant viruses. Aphis gossypii is known as a pest in greenhouses, but our study shows that it occurs also in the field, even far in the north. The novel information on aphid phenology and ecology has wide implications for prospective pest management, particularly in light of climate change.

  18. The phytopathogen Dickeya dadantii (Erwinia chrysanthemi 3937) is a pathogen of the pea aphid.

    Science.gov (United States)

    Grenier, Anne-Marie; Duport, Gabrielle; Pagès, Sylvie; Condemine, Guy; Rahbé, Yvan

    2006-03-01

    Dickeya dadantii (Erwinia chrysanthemi) is a phytopathogenic bacterium causing soft rot diseases on many crops. The sequencing of its genome identified four genes encoding homologues of the Cyt family of insecticidal toxins from Bacillus thuringiensis, which are not present in the close relative Pectobacterium carotovorum subsp. atrosepticum. The pathogenicity of D. dadantii was tested on the pea aphid Acyrthosiphon pisum, and the bacterium was shown to be highly virulent for this insect, either by septic injury or by oral infection. The lethal inoculum dose was calculated to be as low as 10 ingested bacterial cells. A D. dadantii mutant with the four cytotoxin genes deleted showed a reduced per os virulence for A. pisum, highlighting the potential role of at least one of these genes in pathogenicity. Since only one bacterial pathogen of aphids has been previously described (Erwinia aphidicola), other species from the same bacterial group were tested. The pathogenic trait for aphids was shown to be widespread, albeit variable, within the phytopathogens, with no link to phylogenetic positioning in the Enterobacteriaceae. Previously characterized gut symbionts from thrips (Erwinia/Pantoea group) were also highly pathogenic to the aphid, whereas the potent entomopathogen Photorhabdus luminescens was not. D. dadantii is not a generalist insect pathogen, since it has low pathogenicity for three other insect species (Drosophila melanogaster, Sitophilus oryzae, and Spodoptera littoralis). D. dadantii was one of the most virulent aphid pathogens in our screening, and it was active on most aphid instars, except for the first one, probably due to anatomical filtering. The observed difference in virulence toward apterous and winged aphids may have an ecological impact, and this deserves specific attention in future research.

  19. Morphing hull implementation for unmanned underwater vehicles

    International Nuclear Information System (INIS)

    Miller, Timothy F; Gandhi, Farhan; Rufino, Russell J

    2013-01-01

    There has been much interest and work in the area of morphing aircraft since the 1980s. Morphing could also potentially benefit unmanned underwater vehicles (UUVs). The current paper envisions a UUV with an interior pressure hull and a variable diameter outer flexible hull with fuel stored in the annulus between, and presents a mechanism to realize diameter change of the outer hull. The outer hull diameter of UUVs designed for very long endurance/range could be progressively reduced as fuel was consumed, thereby reducing drag and further increasing endurance and range capability. Diameter morphing could also be advantageous for compact storage of UUVs. A prototype is fabricated to represent an axial section of such a morphing diameter UUV. Diameter change is achieved using eight morphing trusses arranged equidistant around the circumference of the representative interior rigid hull. Each morphing truss has a lower rail (attached to the rigid hull) and an upper rail with V-linkages between, at either ends of the rail. Horizontal motion of the feet of the V-linkages (sliding in the lower rail) results in vertical motion of the upper rail which in turn produces diameter change of the outer hull. For the prototype built and tested, a 63% increase in outer diameter from 12.75″ to 20.75″ was achieved. The introduction of a stretched latex representative flexible skin around the outer rails increased actuation force requirement and led to a propensity for the wheel-in-track sliders in the morphing truss to bind. It is anticipated that this could be overcome with higher precision manufacturing. In addition to symmetric actuation of the morphing trusses resulting in diameter change, the paper also shows that with asymmetric actuation the hull cross-section shape can be changed (for example, from a circular section for underwater operation to a V-section for surface operations). (paper)

  20. Do aphid carcasses on the backs of larvae of green lacewing work as chemical mimicry against aphid-tending ants?

    Science.gov (United States)

    Hayashi, Masayuki; Choh, Yasuyuki; Nakamuta, Kiyoshi; Nomura, Masashi

    2014-06-01

    Ants attack and exclude natural enemies of aphids in ant-aphid mutualisms. However, larvae of the green lacewing, Mallada desjardinsi, prey on the cowpea aphid, Aphis craccivora, without exclusion by aphid-tending ants. Lacewing larvae are protected from ants by carrying aphid carcasses on their backs. Here, we tested whether cuticular hydrocarbons (CHCs) of aphid carcasses affected the aggressiveness of aphid-tending ants. Aphid carcasses were washed with n-hexane to remove lipids. Lacewing larvae with washed aphid carcasses were attacked by aphid-tending ants more frequently than those with untreated aphid carcasses. We measured the aggressiveness of aphid-tending ants to lacewing larvae that were either carrying a piece of cotton wool (a dummy aphid carcass) treated with CHCs from aphids or lacewing larvae, or carrying aphid carcasses. The rates of attack by ants on lacewing larvae carrying CHCs of aphids or aphid carcasses were lower than that of attack on lacewing larvae with conspecific CHCs. Chemical analysis by gas chromatography/mass spectrometry showed similarity of CHCs between aphids and aphid carcasses. These results suggest that aphid carcasses on the backs of lacewing larvae function via chemical camouflage to limit attacks by aphid-tending ants.

  1. Rice-straw mulch reduces the green peach aphid, Myzus persicae (Hemiptera: Aphididae) populations on kale, Brassica oleracea var. acephala (Brassicaceae) plants.

    Science.gov (United States)

    Silva-Filho, Reinildes; Santos, Ricardo Henrique Silva; Tavares, Wagner de Souza; Leite, Germano Leão Demolin; Wilcken, Carlos Frederico; Serrão, José Eduardo; Zanuncio, José Cola

    2014-01-01

    Organic mulches, like peel and rice-straw, besides other materials affect the UV and temperature, which cause a reduction in the aphid arrival. The aim was to evaluate the effect of covering the soil with straw on the populations of the green peach aphid, Myzus persicae on the kale, Brassica oleracea var. acephala plants. The first experiment evaluated the direct effect of the rice-straw mulch and the second its indirect effect on aphid immigration, testing the plant characteristics that could lead to the landing preference of this insect. The third experiment evaluated the direct effect of the mulch on the aphid population. In the second and third experiments, four plants, each in a 14 L polyethylene pot with holes at the bottom, were used in areas with and without soil mulching. These pots were changed between areas, after seven days, to evaluate the effects of this change on the arrival of the winged aphids to the plants. Each plant was covered with anti-aphid gauze and inoculated with one winged M. persicae. Winged and apterous adults of this insect were counted per plant after 15 days. The temperature increased in the mulched plots to a maximum of 21-36°C and to 18-32°C in the plots with or without soil covering, respectively. Plant growth reduced the numbers of the winged aphids landing before and after they were moved to the bare soil plots. The nutrient content was similar in plants in both the mulched and no mulched plots. The population growth of M. persicae was higher in the control than in the mulched plots. This was partially due to temperatures close to 30°C in these plots and changes in the plant physiology. The soil mulching with rice-straw decreased the M. persicae landing, increased the plot temperatures and improved the vegetative growth of the kale plants.

  2. Rice-straw mulch reduces the green peach aphid, Myzus persicae (Hemiptera: Aphididae populations on kale, Brassica oleracea var. acephala (Brassicaceae plants.

    Directory of Open Access Journals (Sweden)

    Reinildes Silva-Filho

    Full Text Available Organic mulches, like peel and rice-straw, besides other materials affect the UV and temperature, which cause a reduction in the aphid arrival. The aim was to evaluate the effect of covering the soil with straw on the populations of the green peach aphid, Myzus persicae on the kale, Brassica oleracea var. acephala plants. The first experiment evaluated the direct effect of the rice-straw mulch and the second its indirect effect on aphid immigration, testing the plant characteristics that could lead to the landing preference of this insect. The third experiment evaluated the direct effect of the mulch on the aphid population. In the second and third experiments, four plants, each in a 14 L polyethylene pot with holes at the bottom, were used in areas with and without soil mulching. These pots were changed between areas, after seven days, to evaluate the effects of this change on the arrival of the winged aphids to the plants. Each plant was covered with anti-aphid gauze and inoculated with one winged M. persicae. Winged and apterous adults of this insect were counted per plant after 15 days. The temperature increased in the mulched plots to a maximum of 21-36°C and to 18-32°C in the plots with or without soil covering, respectively. Plant growth reduced the numbers of the winged aphids landing before and after they were moved to the bare soil plots. The nutrient content was similar in plants in both the mulched and no mulched plots. The population growth of M. persicae was higher in the control than in the mulched plots. This was partially due to temperatures close to 30°C in these plots and changes in the plant physiology. The soil mulching with rice-straw decreased the M. persicae landing, increased the plot temperatures and improved the vegetative growth of the kale plants.

  3. Efficacy of Chemical Mimicry by Aphid Predators Depends on Aphid-Learning by Ants.

    Science.gov (United States)

    Hayashi, Masayuki; Nomura, Masashi; Nakamuta, Kiyoshi

    2016-03-01

    Chemical mimicry is an effective strategy when signal receivers recognize and discriminate models by relying on chemical cues. Some aphid enemies mimic the cuticular chemicals of aphids through various means thus avoiding detection and attack by aphid-tending ants. However, because ants have been reported to learn the chemical signatures of aphids in order to distinguish the aphids, the efficacy of chemical mimicry is predicted to depend on the experience of the ants that had tended aphids. The present study tested this hypothesis using two predator species: larvae of the green lacewing Mallada desjardinsi, and larvae of the ladybeetle Scymnus posticalis. Lacewing larvae carry the carcasses of aphids on which they have preyed upon their backs, and these function via chemical camouflage to reduce the aggressiveness of aphid-tending ants toward the larvae. Ladybeetle larvae reportedly produce a covering of wax structures, and their chemicals appear to attenuate ant aggression. We examined whether the behavior of the ant Tetramorium tsushimae toward these predators changed depending on their aphid-tending experience. Ants moderated their aggressiveness toward both predators when they had previously tended aphids, indicating that chemical mimicry by both aphid predators is dependent on previous experience of the ants in tending aphids. Chemical mimicry by the predators of ant-tended aphids is therefore considered to exploit learning-dependent aphid recognition systems of ants.

  4. A bio-inspired, active morphing skin for camber morphing structures

    International Nuclear Information System (INIS)

    Feng, Ning; Leng, Jinson; Liu, Liwu; Liu, Yanju

    2015-01-01

    In this study, one kind of developed morphing skin embedded with pneumatic muscle fibers (PMFs) was manufactured and was employed for camber morphing structures. The output force and contraction of PMF as well as the morphing skin were experimentally characterized at a series of discrete actuator pressures varying from 0.15 to 0.35 MPa. The active morphing skin test results show that the output force is 73.59 N and the contraction is 0.097 (9.7%) at 0.35 MPa. Due to these properties, this active morphing skin could be easily used for the morphing structures. Then the proper airfoil profile was chosen to manufacture the adaptive airfoil in this study. The chord-wise bending airfoil structure was achieved by employing this kind of active morphing skin. Finally the deformed shapes of this chord-wise bending airfoil structure were obtained by 3-dimensions scanning measurement. Meanwhile the camber morphing structures were analyzed through the finite element method (FEM) and the deformed shapes of the upper surface skins were obtained. The experimental result and FEM analysis result of deformed shapes of the upper surface skins were compared in this paper. (paper)

  5. A bio-inspired, active morphing skin for camber morphing structures

    Science.gov (United States)

    Feng, Ning; Liu, Liwu; Liu, Yanju; Leng, Jinson

    2015-03-01

    In this study, one kind of developed morphing skin embedded with pneumatic muscle fibers (PMFs) was manufactured and was employed for camber morphing structures. The output force and contraction of PMF as well as the morphing skin were experimentally characterized at a series of discrete actuator pressures varying from 0.15 to 0.35 MPa. The active morphing skin test results show that the output force is 73.59 N and the contraction is 0.097 (9.7%) at 0.35 MPa. Due to these properties, this active morphing skin could be easily used for the morphing structures. Then the proper airfoil profile was chosen to manufacture the adaptive airfoil in this study. The chord-wise bending airfoil structure was achieved by employing this kind of active morphing skin. Finally the deformed shapes of this chord-wise bending airfoil structure were obtained by 3-dimensions scanning measurement. Meanwhile the camber morphing structures were analyzed through the finite element method (FEM) and the deformed shapes of the upper surface skins were obtained. The experimental result and FEM analysis result of deformed shapes of the upper surface skins were compared in this paper.

  6. Quantitation and localization of pospiviroids in aphids.

    Science.gov (United States)

    Van Bogaert, N; De Jonghe, K; Van Damme, E J M; Maes, M; Smagghe, G

    2015-01-01

    In this paper, the potential role of aphids in viroid transmission was explored. Apterous aphids were fed on pospiviroid-infected plants and viroid targets in the aphids were consequently quantified through RT-qPCR and localized within the aphid body using fluorescence in situ hybridization (FISH). Based on the analytical sensitivity test, the limit of detection (LOD) was estimated at 1.69×10(6) viroid copies per individual aphid body. To localize the viroids in the aphids, a pospiviroid-generic Cy5-labelled probe was used and the fluorescent signal was determined by confocal microscopy. Viroids were clearly observed in the aphid's stylet and stomach, but not in the embryos. Viroids were detected in 29% of the aphids after a 24h feeding period, which suggests only a partial and low concentration viroid uptake by the aphid population including viroid concentrations under the LOD. However, these results show that viroids can be ingested by aphids while feeding on infected plants, thus potentially increasing the transmission risk. The combination of FISH and RT-qPCR provides reliable and fast localization and quantitation of viroid targets in individual aphids and thus constitutes a valuable tool in future epidemiological research. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. The role of wing kinematics of freely flying birds downstream the wake of flapping wings

    Science.gov (United States)

    Krishnan, Krishnamoorthy; Gurka, Roi

    2016-11-01

    Avian aerodynamics has been a topic of research for centuries. Avian flight features such as flapping, morphing and maneuvering make bird aerodynamics a complex system to study, analyze and understand. Aerodynamic performance of the flapping wings can be quantified by measuring the vortex structures present in the downstream wake. Still, the direct correlation between the flapping wing kinematics and the evolution of wake features need to be established. In this present study, near wake of three bird species (western sandpiper, European starling and American robin) have been measured experimentally. Long duration, time-resolved, particle image velocimetry technique has been used to capture the wake properties. Simultaneously, the bird kinematics have been captured using high speed camera. Wake structures are reconstructed from the collected PIV images for long chord distances downstream. Wake vorticities and circulation are expressed in the wake composites. Comparison of the wake features of the three birds shows similarities and some key differences are also found. Wing tip motions of the birds are extracted for four continuous wing beat cycle to analyze the wing kinematics. Kinematic parameters of all the three birds are compared to each other and similar trends exhibited by all the birds have been observed. A correlation between the wake evolutions with the wing motion is presented. It was found that the wings' motion generates unique flow patterns at the near wake, especially at the transition phases. At these locations, a drastic change in the circulation was observed.

  8. Aerodynamic Analysis of Morphing Blades

    Science.gov (United States)

    Harris, Caleb; Macphee, David; Carlisle, Madeline

    2016-11-01

    Interest in morphing blades has grown with applications for wind turbines and other aerodynamic blades. This passive control method has advantages over active control methods such as lower manufacturing and upkeep costs. This study has investigated the lift and drag forces on individual blades with experimental and computational analysis. The goal has been to show that these blades delay stall and provide larger lift-to-drag ratios at various angles of attack. Rigid and flexible airfoils were cast from polyurethane and silicone respectively, then lift and drag forces were collected from a load cell during 2-D testing in a wind tunnel. Experimental data was used to validate computational models in OpenFOAM. A finite volume fluid-structure-interaction solver was used to model the flexible blade in fluid flow. Preliminary results indicate delay in stall and larger lift-to-drag ratios by maintaining more optimal angles of attack when flexing. Funding from NSF REU site Grant EEC 1358991 is greatly appreciated.

  9. Topology optimization of pressure adaptive honeycomb for a morphing flap

    Science.gov (United States)

    Vos, Roelof; Scheepstra, Jan; Barrett, Ron

    2011-03-01

    The paper begins with a brief historical overview of pressure adaptive materials and structures. By examining avian anatomy, it is seen that pressure-adaptive structures have been used successfully in the Natural world to hold structural positions for extended periods of time and yet allow for dynamic shape changes from one flight state to the next. More modern pneumatic actuators, including FAA certified autopilot servoactuators are frequently used by aircraft around the world. Pneumatic artificial muscles (PAM) show good promise as aircraft actuators, but follow the traditional model of load concentration and distribution commonly found in aircraft. A new system is proposed which leaves distributed loads distributed and manipulates structures through a distributed actuator. By using Pressure Adaptive Honeycomb (PAH), it is shown that large structural deformations in excess of 50% strains can be achieved while maintaining full structural integrity and enabling secondary flight control mechanisms like flaps. The successful implementation of pressure-adaptive honeycomb in the trailing edge of a wing section sparked the motivation for subsequent research into the optimal topology of the pressure adaptive honeycomb within the trailing edge of a morphing flap. As an input for the optimization two known shapes are required: a desired shape in cruise configuration and a desired shape in landing configuration. In addition, the boundary conditions and load cases (including aerodynamic loads and internal pressure loads) should be specified for each condition. Finally, a set of six design variables is specified relating to the honeycomb and upper skin topology of the morphing flap. A finite-element model of the pressure-adaptive honeycomb structure is developed specifically tailored to generate fast but reliable results for a given combination of external loading, input variables, and boundary conditions. Based on two bench tests it is shown that this model correlates well

  10. Plant immunity in plant–aphid interactions

    Science.gov (United States)

    Jaouannet, Maëlle; Rodriguez, Patricia A.; Lenoir, Camille J. G.; MacLeod, Ruari; Escudero-Martinez, Carmen; Bos, Jorunn I.B.

    2014-01-01

    Aphids are economically important pests that cause extensive feeding damage and transmit viruses. While some species have a broad host range and cause damage to a variety of crops, others are restricted to only closely related plant species. While probing and feeding aphids secrete saliva, containing effectors, into their hosts to manipulate host cell processes and promote infestation. Aphid effector discovery studies pointed out parallels between infection and infestation strategies of plant pathogens and aphids. Interestingly, resistance to some aphid species is known to involve plant resistance proteins with a typical NB-LRR domain structure. Whether these resistance proteins indeed recognize aphid effectors to trigger ETI remains to be elucidated. In addition, it was recently shown that unknown aphid derived elicitors can initiate reactive oxygen species (ROS) production and callose deposition and that these responses were dependent on BAK1 (BRASSINOSTERIOD INSENSITIVE 1-ASSOCIATED RECEPTOR KINASE 1) which is a key component of the plant immune system. In addition, BAK-1 contributes to non-host resistance to aphids pointing to another parallel between plant-pathogen and – aphid interactions. Understanding the role of plant immunity and non-host resistance to aphids is essential to generate durable and sustainable aphid control strategies. Although insect behavior plays a role in host selection and non-host resistance, an important observation is that aphids interact with non-host plants by probing the leaf surface, but are unable to feed or establish colonization. Therefore, we hypothesize that aphids interact with non-host plants at the molecular level, but are potentially not successful in suppressing plant defenses and/or releasing nutrients. PMID:25520727

  11. SOYBEAN.APHID.SD.2017

    Science.gov (United States)

    Infestations by soybean aphid (SA) can reduce soybean yield. Thus, SA-resistant soybean may be useful in reducing infestations and limiting yield loss. Expression of resistance was characterized among 746 soybean accessions in 56 growth chamber tests at the North Central Agricultural Research Labo...

  12. Morphing patient-specific musculoskeletal models

    DEFF Research Database (Denmark)

    Rasmussen, John; Galibarov, Pavel E.; Al-Munajjed, Amir

    or surface scans. Furthermore, we assume that a set of corresponding anatomical landmarks can be identified in the medical imaging data and on the generic musculoskeletal model. A nonlinear transformation, i.e. a morphing, is created by means of radial basis functions that maps points set (i) to point set...... (ii). The morphing is subsequently used to transform parts of the generic musculoskeletal model to a patient-specific version, thus changing bone shapes, muscle insertion points, joint locations and other geometrical properties. Research questions include how to select point sets and whether...... other conditions may require CT or MRI data. The method and its theoretical assumptions, advantages and limitations are presented, and several examples will illustrate morphing to patient-specific models. [1] Carbes S; Tørholm S; Rasmussen, J. A Detailed Twenty-six Segments Kinematic Foot model...

  13. Prototype Morphing Fan Nozzle Demonstrated

    Science.gov (United States)

    Lee, Ho-Jun; Song, Gang-Bing

    2004-01-01

    Ongoing research in NASA Glenn Research Center's Structural Mechanics and Dynamics Branch to develop smart materials technologies for aeropropulsion structural components has resulted in the design of the prototype morphing fan nozzle shown in the photograph. This prototype exploits the potential of smart materials to significantly improve the performance of existing aircraft engines by introducing new inherent capabilities for shape control, vibration damping, noise reduction, health monitoring, and flow manipulation. The novel design employs two different smart materials, a shape-memory alloy and magnetorheological fluids, to reduce the nozzle area by up to 30 percent. The prototype of the variable-area fan nozzle implements an overlapping spring leaf assembly to simplify the initial design and to provide ease of structural control. A single bundle of shape memory alloy wire actuators is used to reduce the nozzle geometry. The nozzle is subsequently held in the reduced-area configuration by using magnetorheological fluid brakes. This prototype uses the inherent advantages of shape memory alloys in providing large induced strains and of magnetorheological fluids in generating large resistive forces. In addition, the spring leaf design also functions as a return spring, once the magnetorheological fluid brakes are released, to help force the shape memory alloy wires to return to their original position. A computerized real-time control system uses the derivative-gain and proportional-gain algorithms to operate the system. This design represents a novel approach to the active control of high-bypass-ratio turbofan engines. Researchers have estimated that such engines will reduce thrust specific fuel consumption by 9 percent over that of fixed-geometry fan nozzles. This research was conducted under a cooperative agreement (NCC3-839) at the University of Akron.

  14. Parametric dependence of a morphing wind turbine blade on material elasticity

    International Nuclear Information System (INIS)

    Puterbaugh, Martin; Beyene, Asfaw

    2011-01-01

    A few recent works have suggested a morphing blade for wind turbine energy conversion. The concept is derived from fin and wing motions that better adapt to varying load conditions. Previous research has provided the fluid mechanic justification of this new concept. This paper establishes a parametric relationship between an asymmetric wind turbine blade and constituent material modulus to predict the geometric response of the morphing blade for a given material characteristic. The airfoil's trailing edge deflection is associated to a prescribed fluid exit angle via the Moment Area (MA) method. Subsequently, a mathematical model is derived to predict material deformation with respect to imparted aerodynamic forces. Results show that an airfoil, much like a tapered beam, can be modeled as a non-prismatic cantilevered beam using this well established method. -- Research highlights: →A mathematical model relating morphing airfoil thickness and elastic modulus was established. →For non-prismatic beam under a uniform distributive load, the slope and deflection of the airfoil's trailing edge were related to the fluid exit angle. →The main driver of blade deformation was the angular drag force. The Moment Area method was used, verified by Finite Element method. →Displacement to the exit angle is predicated upon the elastic modulus value given that other parameters are constant. →Optimum power output is obtained in part load conditions when the blade deforms to the applicable exit angle.

  15. Altruistic defence behaviours in aphids

    Directory of Open Access Journals (Sweden)

    Brodeur Jacques

    2010-01-01

    Full Text Available Abstract Background Altruistic anti-predatory behaviours pose an evolutionary problem because they are costly to the actor and beneficial to the recipients. Altruistic behaviours can evolve through indirect fitness benefits when directed toward kin. The altruistic nature of anti-predatory behaviours is often difficult to establish because the actor can obtain direct fitness benefits, or the behaviour could result from selfish coercion by others, especially in eusocial animals. Non-eusocial parthenogenetically reproducing aphids form colonies of clone-mates, which are ideal to test the altruistic nature of anti-predatory defence behaviours. Many aphids release cornicle secretions when attacked by natural enemies such as parasitoids. These secretions contain an alarm pheromone that alerts neighbours (clone-mates of danger, thereby providing indirect fitness benefits to the actor. However, contact with cornicle secretions also hampers an attacker and could provide direct fitness to the actor. Results We tested the hypothesis that cornicle secretions are altruistic by assessing direct and indirect fitness consequences of smearing cornicle secretions onto an attacker, and by manipulating the number of clone-mates that could benefit from the behaviour. We observed parasitoids, Aphidius rhopalosiphi, foraging singly in patches of the cereal aphid Sitobion avenae of varied patch size (2, 6, and 12 aphids. Aphids that smeared parasitoids did not benefit from a reduced probability of parasitism, or increase the parasitoids' handling time. Smeared parasitoids, however, spent proportionately more time grooming and less time foraging, which resulted in a decreased host-encounter and oviposition rate within the host patch. In addition, individual smearing rate increased with the number of clone-mates in the colony. Conclusions Cornicle secretions of aphids were altruistic against parasitoids, as they provided no direct fitness benefits to secretion

  16. The effects of monitoring the abundance and species composition of aphids as virus vectors on seed potato production in Serbia

    Directory of Open Access Journals (Sweden)

    Drago Milošević

    2014-03-01

    Full Text Available Aphids are the most important vectors of potato viruses during the crop’s growing season. The most widespread and damaging viruses, the potato virus Y and potato leaf roll virus, are transmitted by aphids in non-persistent and persistent manner, respectively. The two viruses cause the greatest concern of potato producers and a great constraint to seed potato production in Serbia, the region and across the world. Potato virus Y is particularly harmful, given its distribution and spreading rate. Seed potato production systems under well-managed conditions involve a series of virus control measures, including the monitoring of outbreaks of winged aphids, their abundance and species composition, in order to forecast virosis, i.e. potential plant and tuber infection periods. Monitoring the aphid vectors of potato viruses enables determination of optimum dates for haulm destruction when higher than normal numbers of winged aphids as vectors of economically harmful diseases have been observed. Haulm destruction in a potato crop reduces the risk of plant infection and virus translocation from the aboveground parts to tubers, thus keeping the proportion of infected tubers within tolerance limits allowed for certain categories of seed potatoes. This practice has positive effects if used in combination with other viral disease control measures; otherwise, it becomes ineffective. This paper provides an integral analysis of the effects and role of monitoring outbreaks of aphids, their abundance and species composition in timing haulm growth termination to prevent plant infection, virus translocation and tuber infestation in potato crops in Serbia and the wider region.

  17. Aphid aerial density profiles are consistent with turbulent advection amplifying flight behaviours: abandoning the epithet 'passive'.

    Science.gov (United States)

    Reynolds, Andy M; Reynolds, Don R

    2009-01-07

    Seminal field studies led by C. G. Johnson in the 1940s and 1950s showed that aphid aerial density diminishes with height above the ground such that the linear regression coefficient, b, of log density on log height provides a single-parameter characterization of the vertical density profile. This coefficient decreases with increasing atmospheric stability, ranging from -0.27 for a fully convective boundary layer to -2.01 for a stable boundary layer. We combined a well-established Lagrangian stochastic model of atmospheric dispersal with simple models of aphid behaviour in order to account for the range of aerial density profiles. We show that these density distributions are consistent with the aphids producing just enough lift to become neutrally buoyant when they are in updraughts and ceasing to produce lift when they are in downdraughts. This active flight behaviour in a weak flier is thus distinctly different from the aerial dispersal of seeds and wingless arthropods, which is passive once these organisms have launched into the air. The novel findings from the model indicate that the epithet 'passive' often applied to the windborne migration of small winged insects is misleading and should be abandoned. The implications for the distances traversed by migrating aphids under various boundary-layer conditions are outlined.

  18. MORPH-PRO: a novel algorithm and web server for protein morphing.

    Science.gov (United States)

    Castellana, Natalie E; Lushnikov, Andrey; Rotkiewicz, Piotr; Sefcovic, Natasha; Pevzner, Pavel A; Godzik, Adam; Vyatkina, Kira

    2013-07-11

    Proteins are known to be dynamic in nature, changing from one conformation to another while performing vital cellular tasks. It is important to understand these movements in order to better understand protein function. At the same time, experimental techniques provide us with only single snapshots of the whole ensemble of available conformations. Computational protein morphing provides a visualization of a protein structure transitioning from one conformation to another by producing a series of intermediate conformations. We present a novel, efficient morphing algorithm, Morph-Pro based on linear interpolation. We also show that apart from visualization, morphing can be used to provide plausible intermediate structures. We test this by using the intermediate structures of a c-Jun N-terminal kinase (JNK1) conformational change in a virtual docking experiment. The structures are shown to dock with higher score to known JNK1-binding ligands than structures solved using X-Ray crystallography. This experiment demonstrates the potential applications of the intermediate structures in modeling or virtual screening efforts. Visualization of protein conformational changes is important for characterization of protein function. Furthermore, the intermediate structures produced by our algorithm are good approximations to true structures. We believe there is great potential for these computationally predicted structures in protein-ligand docking experiments and virtual screening. The Morph-Pro web server can be accessed at http://morph-pro.bioinf.spbau.ru.

  19. Automatic face morphing for transferring facial animation

    NARCIS (Netherlands)

    Bui Huu Trung, B.H.T.; Bui, T.D.; Poel, Mannes; Heylen, Dirk K.J.; Nijholt, Antinus; Hamza, H.M.

    2003-01-01

    In this paper, we introduce a novel method of automatically finding the training set of RBF networks for morphing a prototype face to represent a new face. This is done by automatically specifying and adjusting corresponding feature points on a target face. The RBF networks are then used to transfer

  20. Aphid alarm pheromone as a cue for ants to locate aphid partners.

    Directory of Open Access Journals (Sweden)

    François J Verheggen

    Full Text Available The mutualistic relationships that occur between myrmecophilous aphids and ants are based on the rich food supply that honeydew represents for ants and on the protection they provide against aphid natural enemies. While aphid predators and parasitoids actively forage for oviposition sites by using aphid semiochemicals, scouts of aphid-tending ant species would also benefit from locating honeydew resources by orienting toward aphid pheromone sources. The present study aims to provide additional information on the use of Aphis fabae alarm pheromone, i.e. (E-β-farnesene (EβF, by ant scouts. The perception and behavioral impact of EβF on Lasius niger were investigated using electroantennography and two bio-assays measuring their attraction and orientation towards aphid semiochemicals. Pronounced electrical depolarizations were observed from L. niger scout antennae to stimulations of A. fabae alarm pheromone, while other sesquiterpenes elicited weak or no responses. L. niger scouts were significantly attracted toward EβF in a four-arm olfactometer, as well as in an two-choice bioassay. These laboratory results suggest for the first time that low amounts of aphid alarm pheromone can be used by L. niger scouts as a cue indicating the presence of aphid colonies and could therefore mediate the aphid-ant partnership in the field.

  1. Topology optimization of compliant adaptive wing leading edge with composite materials

    Directory of Open Access Journals (Sweden)

    Tong Xinxing

    2014-12-01

    Full Text Available An approach for designing the compliant adaptive wing leading edge with composite material is proposed based on the topology optimization. Firstly, an equivalent constitutive relationship of laminated glass fiber reinforced epoxy composite plates has been built based on the symmetric laminated plate theory. Then, an optimization objective function of compliant adaptive wing leading edge was used to minimize the least square error (LSE between deformed curve and desired aerodynamics shape. After that, the topology structures of wing leading edge of different glass fiber ply-orientations were obtained by using the solid isotropic material with penalization (SIMP model and sensitivity filtering technique. The desired aerodynamics shape of compliant adaptive wing leading edge was obtained based on the proposed approach. The topology structures of wing leading edge depend on the glass fiber ply-orientation. Finally, the corresponding morphing experiment of compliant wing leading edge with composite materials was implemented, which verified the morphing capability of topology structure and illustrated the feasibility for designing compliant wing leading edge. The present paper lays the basis of ply-orientation optimization for compliant adaptive wing leading edge in unmanned aerial vehicle (UAV field.

  2. Design of LPV-Based Sliding Mode Controller with Finite Time Convergence for a Morphing Aircraft

    Directory of Open Access Journals (Sweden)

    Nuan Wen

    2017-01-01

    Full Text Available This paper proposes a finite time convergence sliding mode control (FSMC strategy based on linear parameter-varying (LPV methodology for the stability control of a morphing aircraft subject to parameter uncertainties and external disturbances. Based on the Kane method, a longitudinal dynamic model of the morphing aircraft is built. Furthermore, the linearized LPV model of the aircraft in the wing transition process is obtained, whose scheduling parameters are wing sweep angle and wingspan. The FSMC scheme is developed into LPV systems by applying the previous results for linear time-invariant (LTI systems. The sufficient condition in form of linear matrix inequality (LMI constraints is derived for the existence of a reduced-order sliding mode, in which the dynamics can be ensured to keep robust stability and L2 gain performance. The tensor-product (TP model transformation approach can be directly applied to solve infinite LMIs belonging to the polynomial parameter-dependent LPV system. Then, by the parameter-dependent Lyapunov function stability analysis, the synthesized FSMC is proved to drive the LPV system trajectories toward the predefined switching surface with a finite time arrival. Comparative simulation results in the nonlinear model demonstrate the robustness and effectiveness of this approach.

  3. Aphid-proof plants: biotechnology-based approaches for aphid control.

    Science.gov (United States)

    Will, Torsten; Vilcinskas, Andreas

    2013-01-01

    Aphids are economically significant agricultural pests that are responsible for large yield losses in many different crops. Because the use of insecticides is restricted in the context of integrated pest management and aphids develop resistance against them rapidly, new biotechnology-based approaches are required for aphid control. These approaches focus on the development of genetically modified aphid-resistant plants that express protease inhibitors, dsRNA, antimicrobial peptides, or repellents, thus addressing different levels of aphid-plant interactions. However, a common goal is to disturb host plant acceptance by aphids and to disrupt their ability to take nutrition from plants. The defense agents negatively affect different fitness-associated parameters such as growth, reproduction, and survival, which therefore reduce the impact of infestations. The results from several different studies suggest that biotechnology-based approaches offer a promising strategy for aphid control.

  4. What do spring migrants reveal about sex and host selection in the melon aphid?

    Directory of Open Access Journals (Sweden)

    Thomas Sophie

    2012-04-01

    Full Text Available Abstract Background Host plants exert considerable selective pressure on aphids because the plants constitute their feeding, mating and oviposition sites. Therefore, host specialisation in aphids evolves through selection of the behavioural and chemical mechanisms of host-plant location and recognition, and through metabolic adaptation to the phloem content of the host plant. How these adaptive traits evolve in an aphid species depends on the complexity of the annual life cycle of that species. The purpose of this field study was to determine how winged spring-migrant populations contribute to the evolution and maintenance of host specialisation in Aphis gossypii through host-plant choice and acceptance. We also assessed whether host-specialised genotypes corresponded exclusively to anholocyclic lineages regardless of the environmental conditions. Results The spring populations of cotton-melon aphids visiting newly planted melon crops exhibited an unexpectedly high level of genetic diversity that contrasted with the very low diversity characterising the host-specialised populations of this aphid species. This study illustrated in natura host-plant-selection pressure by showing the great differences in genetic diversity between the spring-migrant populations (alate aphids and the melon-infesting populations (the apterous offspring of the alate aphids. Moreover, an analysis of the genetic composition of these alate and apterous populations in four geographic regions suggested differences in life-history strategies, such as host choice and reproductive mode, and questioned the common assertion that A. gossypii is an anholocyclic species throughout its distribution area, including Europe. Conclusions Our results clearly demonstrate that the melon plant acts as a selective filter against the reproduction of non-specialised individuals. We showed that olfactory cues are unlikely to be decisive in natura for host recognition by spring-migrant aphid

  5. A functional genomics approach identifies candidate effectors from the aphid species Myzus persicae (green peach aphid.

    Directory of Open Access Journals (Sweden)

    Jorunn I B Bos

    2010-11-01

    Full Text Available Aphids are amongst the most devastating sap-feeding insects of plants. Like most plant parasites, aphids require intimate associations with their host plants to gain access to nutrients. Aphid feeding induces responses such as clogging of phloem sieve elements and callose formation, which are suppressed by unknown molecules, probably proteins, in aphid saliva. Therefore, it is likely that aphids, like plant pathogens, deliver proteins (effectors inside their hosts to modulate host cell processes, suppress plant defenses, and promote infestation. We exploited publicly available aphid salivary gland expressed sequence tags (ESTs to apply a functional genomics approach for identification of candidate effectors from Myzus persicae (green peach aphid, based on common features of plant pathogen effectors. A total of 48 effector candidates were identified, cloned, and subjected to transient overexpression in Nicotiana benthamiana to assay for elicitation of a phenotype, suppression of the Pathogen-Associated Molecular Pattern (PAMP-mediated oxidative burst, and effects on aphid reproductive performance. We identified one candidate effector, Mp10, which specifically induced chlorosis and local cell death in N. benthamiana and conferred avirulence to recombinant Potato virus X (PVX expressing Mp10, PVX-Mp10, in N. tabacum, indicating that this protein may trigger plant defenses. The ubiquitin-ligase associated protein SGT1 was required for the Mp10-mediated chlorosis response in N. benthamiana. Mp10 also suppressed the oxidative burst induced by flg22, but not by chitin. Aphid fecundity assays revealed that in planta overexpression of Mp10 and Mp42 reduced aphid fecundity, whereas another effector candidate, MpC002, enhanced aphid fecundity. Thus, these results suggest that, although Mp10 suppresses flg22-triggered immunity, it triggers a defense response, resulting in an overall decrease in aphid performance in the fecundity assays. Overall, we

  6. Numerical and experimental study of bistable plates for morphing structures

    Science.gov (United States)

    Nicassio, F.; Scarselli, G.; Avanzini, G.; Del Core, G.

    2017-04-01

    This study is concerned with the activation energy threshold of bistable composite plates in order to tailor a bistable system for specific aeronautical applications. The aim is to explore potential configurations of the bistable plates and their dynamic behavior for designing novel morphing structure suitable for aerodynamic surfaces and, as a possible further application, for power harvesters. Bistable laminates have two stable mechanical shapes that can withstand aerodynamic loads without additional constraint forces or locking mechanisms. This kind of structures, when properly loaded, snap-through from one stable configuration to another, causing large strains that can also be used for power harvesting scopes. The transition between the stable states of the composite laminate can be triggered, in principle, simply by aerodynamic loads (pilot, disturbance or passive inputs) without the need of servo-activated control systems. Both numerical simulations based on Finite Element models and experimental testing based on different activating forcing spectra are used to validate this concept. The results show that dynamic activation of bistable plates depend on different parameters that need to be carefully managed for their use as aircraft passive wing flaps.

  7. Stability and morphing characteristics of bistable composite laminates

    Science.gov (United States)

    Tawfik, Samer A.

    The focus of the current research is to investigate the potential of using bistable unsymmetric cross-ply laminated composites as a means for achieving structures with morphed characteristics. To this end, an investigation of the design space for laminated composites exhibiting bistable behavior is undertaken and the key parameters controlling their behavior are identified. For this purpose a nonlinear Finite Element methodology using ABAQUS(TM) code is developed to predict both the cured shapes and the stability characteristics of unsymmetric cross-ply laminates. In addition, an experimental program is developed to validate the analytically predicted results through comparison with test data. A new method is proposed for attaching piezoelectric actuators to a bistable panel in order to preserve its favorable stability characteristics as well as optimizing the actuators performance. The developed nonlinear FE methodology is extended to predict the actuation requirements of bistable panels. Actuator requirements, predicted using the nonlinear FE analysis, are found to be in agreement with the test results. The current research also explores the potential for implementing bistable panels for Uninhabited Aerial Vehicle (UAV) wing configuration. To this end, a set of bistable panels is manufactured by combining symmetric and unsymmetric balanced and unbalanced stacking sequence and their stability characteristics are predicted. A preliminary analysis of the aerodynamic characteristics of the manufactured panels is carried out and the aerodynamic benefits of manufactured bistable panel are noted.

  8. Spruce aphid (Elatobium abietinum Walker) (Hemiptera: Aphididae) [Chapter XXIV

    Science.gov (United States)

    Ann M. Lynch

    2014-01-01

    Elatobium abietinum Walker is a spruce-feeding aphid that in Europe is referred to as the green spruce aphid (Day et al., 1998a) (Fig. 1). However, in North America E. abietinum is known simply as the spruce aphid, while the common name "green spruce aphid" refers to a different species, Cinara fornacula Hottes (Hemiptera: Aphididae) (http://www.entsoc.org/...

  9. Unmanned aircraft system-derived crop height and normalized difference vegetation index metrics for sorghum yield and aphid stress assessment

    Science.gov (United States)

    Stanton, Carly; Starek, Michael J.; Elliott, Norman; Brewer, Michael; Maeda, Murilo M.; Chu, Tianxing

    2017-04-01

    A small, fixed-wing unmanned aircraft system (UAS) was used to survey a replicated small plot field experiment designed to estimate sorghum damage caused by an invasive aphid. Plant stress varied among 40 plots through manipulation of aphid densities. Equipped with a consumer-grade near-infrared camera, the UAS was flown on a recurring basis over the growing season. The raw imagery was processed using structure-from-motion to generate normalized difference vegetation index (NDVI) maps of the fields and three-dimensional point clouds. NDVI and plant height metrics were averaged on a per plot basis and evaluated for their ability to identify aphid-induced plant stress. Experimental soil signal filtering was performed on both metrics, and a method filtering low near-infrared values before NDVI calculation was found to be the most effective. UAS NDVI was compared with NDVI from sensors onboard a manned aircraft and a tractor. The correlation results showed dependence on the growth stage. Plot averages of NDVI and canopy height values were compared with per-plot yield at 14% moisture and aphid density. The UAS measures of plant height and NDVI were correlated to plot averages of yield and insect density. Negative correlations between aphid density and NDVI were seen near the end of the season in the most damaged crops.

  10. Improvement of Barley yellow dwarf virus-PAV detection in single aphids using a fluorescent real time RT-PCR.

    Science.gov (United States)

    Fabre, Frédéric; Kervarrec, Christine; Mieuzet, Lucie; Riault, Gérard; Vialatte, Aude; Jacquot, Emmanuel

    2003-06-09

    One of the major factors determining the incidence of Barley yellow dwarf virus (BYDV) on autumn-sown cereals is the viruliferous state of immigrant winged aphids. This variable is assessed routinely using the enzyme-linked immunosorbant assay (ELISA). However, the threshold for virus detection by ELISA can lead to false negative results for aphids carrying less than 10(6) particles. Although molecular detection techniques enabling the detection of lower virus quantities in samples are available, the relatively laborious sample preparation and data analysis have restricted their use in routine applications. A gel-free real-time one-step reverse transcription polymerase chain reaction (RT-PCR) protocol is described for specific detection and quantitation of BYDV-PAV, the most widespread BYDV species in Western Europe. This new assay, based on TaqMan technology, detects and quantifies from 10(2) to 10(8) BYDV-PAV RNA copies. This test is 10 and 10(3) times more sensitive than the standard RT-PCR and ELISA assays published previously for BYDV-PAV detection and significantly improves virus detection in single aphids. Extraction of nucleic acids from aphids using either phenol/chloroform or chelatin resin-based protocols allow the use of pooled samples or of a small part (up to 1/1600th) of a single aphid extract for efficient BYDV-PAV detection.

  11. Aphid (Hemiptera: Aphididae) species determined on herbaceous ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-06-17

    Jun 17, 2009 ... As a result, total of 28 aphid species belonging to 14 genus and 4 tribes of the super family. Aphidoidea were determined. ... species of Aphidoidea family attack various plants, infest- ing leaves, terms, fruits and roots ... Aphids were collected from their host plants with a fine brush and put in to a tube which ...

  12. Aphid incidence and its correlation with different environmental factors

    OpenAIRE

    Hasan, M.R; Ahmad, M.; Rahman, M.H; Haque, M.A

    2009-01-01

    The aphid incidence and its correlation with environmental factors were studied. Mustard variety “Sampad” was used as test crop. Aphid incidence varied significantly at various parts of mustard plant and time of the day. The highest number of aphid was observed in the vegetative parts of the mustard plant in the morning. High cloudiness, relative humidity and dew point favoured the aphid population and slight rain fall quickly declined the aphid population. Among the different environmental f...

  13. Ant Larval Demand Reduces Aphid Colony Growth Rates in an Ant-Aphid Interaction

    Directory of Open Access Journals (Sweden)

    James M. Cook

    2012-02-01

    Full Text Available Ants often form mutualistic interactions with aphids, soliciting honeydew in return for protective services. Under certain circumstances, however, ants will prey upon aphids. In addition, in the presence of ants aphids may increase the quantity or quality of honeydew produced, which is costly. Through these mechanisms, ant attendance can reduce aphid colony growth rates. However, it is unknown whether demand from within the ant colony can affect the ant-aphid interaction. In a factorial experiment, we tested whether the presence of larvae in Lasius niger ant colonies affected the growth rate of Aphis fabae colonies. Other explanatory variables tested were the origin of ant colonies (two separate colonies were used and previous diet (sugar only or sugar and protein. We found that the presence of larvae in the ant colony significantly reduced the growth rate of aphid colonies. Previous diet and colony origin did not affect aphid colony growth rates. Our results suggest that ant colonies balance the flow of two separate resources from aphid colonies- renewable sugars or a protein-rich meal, depending on demand from ant larvae within the nest. Aphid payoffs from the ant-aphid interaction may change on a seasonal basis, as the demand from larvae within the ant colony waxes and wanes.

  14. Potato aphid salivary proteome: enhanced salivation using resorcinol and identification of aphid phosphoproteins.

    Science.gov (United States)

    Chaudhary, Ritu; Atamian, Hagop S; Shen, Zhouxin; Briggs, Steven P; Kaloshian, Isgouhi

    2015-04-03

    Aphids deliver saliva into plants and acquire plant sap for their nourishment using a specialized mouthpart or stylets. Aphid saliva is of great importance because it contains effectors that are involved in modulating host defense and metabolism. Although profiling aphid salivary glands and identifying secreted proteins have been successfully used, success in direct profiling of aphid saliva have been limited due to scarcity of saliva collected in artificial diets. Here we present the use of a neurostimulant, resorcinol, for inducing aphid salivation. Saliva of potato aphids (Macrosiphum euphorbiae), maintained on tomato, was collected in resorcinol diet. Salivary proteins were identified using mass spectrometry and compared with the existing M. euphorbiae salivary proteome collected in water. Comparative analysis was also performed with existing salivary proteomes from additional aphid species. Most of the proteins identified in the resorcinol diet were also present in the water diet and represented proteins with a plethora of functions in addition to a large number of unknowns. About half of the salivary proteins were not predicted for secretion or had canonical secretion signal peptides. We also analyzed the phosphorylation states of M. euphorbiae salivary proteins and identified three known aphid effectors, Me_WB01635/Mp1, Me10/Mp58, and Me23 that carry phosphorylation marks. In addition to insect proteins, tomato host proteins were also identified in aphid saliva. Our results indicate that aphid saliva is complex and provides a rich resource for functional characterization of effectors.

  15. Environment-mediated morph-linked immune and life-history responses in the aposematic wood tiger moth.

    Science.gov (United States)

    Nokelainen, Ossi; Lindstedt, Carita; Mappes, Johanna

    2013-05-01

    1. Warning signals are expected to evolve towards conspicuousness and monomorphism, and thereby hamper the evolution of multiple colour morphs. Here, we test fitness responses to different rearing densities to explain colour polymorphism in aposematic wood tiger moth (Parasemia plantaginis) males. 2. We used larval lines sired by white or yellow adult males selected for small or large melanization patterns of coloration. We reared these selected lines either solitarily (favourable conditions) or in aggregations (challenged conditions), and followed their performance to adult stage. We tested whether differences in larval density affected life-history traits, adult melanin expression, adult morph (white or yellow) survival and immunological responses. 3. We found that the aggregated environment increased mortality of larvae, but decreased larval developmental time and pupa weight. Adult wing melanin pigmentation was dependent on larval melanin expression but not rearing density. We also confirmed that adult wing coloration had a genetic basis (h(2) = 0.42) and was not influenced by larval growth density. Adult yellow males survived better from aggregations in comparison with white males, which may be related to differences in immune defence. White males had better encapsulation ability, whereas yellow males had increased lytic activity of haemolymph in the aggregations. 4. Our main results highlight, that morph-linked immune responses mediated by differential growth density may facilitate the maintenance of colour polymorphism in aposematic species. In nature, risk of diseases and parasites vary spatially and temporally. Therefore, both yellow and white adult morphs can be maintained due to their differential investment in immune defence in heterogeneous environments. © 2013 The Authors. Journal of Animal Ecology © 2013 British Ecological Society.

  16. Morphing for faster computations in transformation optics.

    Science.gov (United States)

    Aznavourian, Ronald; Guenneau, Sébastien

    2014-11-17

    We propose to use morphing algorithms to deduce some approximate wave pictures of scattering by cylindrical invisibility cloaks of various shapes deduced from the exact computation (e.g. using a finite element method) of scattering by cloaks of two given shapes, say circular and elliptic ones, thereafter called the source and destination images. The error in L(2) norm between the exact and approximate solutions deduced via morphing from the source and destination images is typically less than 2 percent if control points are judiciously chosen. Our approach works equally well for rotators and concentrators, and also unveils some device which we call rotacon since it both rotates and concentrates electromagnetic fields. However, it breaks down for superscatterers (deduced from non-monotonic transforms): the error in L(2) norm is about 25 percent. We stress that our approach might greatly accelerate numerical studies of 2D and 3D cloaks.

  17. Aerodynamic and aeroacoustic performance of airfoils with morphing structures

    OpenAIRE

    Ai, Qing; Azarpeyvand, Mahdi; Lachenal, Xavier; Weaver, Paul M.

    2016-01-01

    Aerodynamic and aeroacoustic performance of airfoils fitted with morphing trailing edges are investigated using a coupled structure/fluid/noise model. The control of the flow over the surface of an airfoil using shape optimization techniques can significantly improve the load distribution along the chord and span lengths whilst minimising noise generation. In this study, a NACA 63-418 airfoil is fitted with a morphing flap and various morphing profiles are considered with two features that di...

  18. Morphing Control Surface for Improved Efficiency and Maneuverability, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The current technology push in advanced aerospace flight systems is to replicate certain features seen in nature. Morphing aircraft, particularly unmanned air...

  19. Transgenerational effects and the cost of ant tending in aphids.

    Science.gov (United States)

    Tegelaar, Karolina; Glinwood, Robert; Pettersson, Jan; Leimar, Olof

    2013-11-01

    In mutualistic interactions, partners obtain a net benefit, but there may also be costs associated with the provision of benefits for a partner. The question of whether aphids suffer such costs when attended by ants has been raised in previous work. Transgenerational effects, where offspring phenotypes are adjusted based on maternal influences, could be important in the mutualistic interaction between aphids and ants, in particular because aphids have telescoping generations where two offspring generations can be present in a mature aphid. We investigated the immediate and transgenerational influence of ant tending on aphid life history and reproduction by observing the interaction between the facultative myrmecophile Aphis fabae and the ant Lasius niger over 13 aphid generations in the laboratory. We found that the effect of ant tending changes dynamically over successive aphid generations after the start of tending. Initially, total aphid colony weight, aphid adult weight and aphid embryo size decreased compared with untended aphids, consistent with a cost of ant association, but these differences disappeared within four generations of interaction. We conclude that transgenerational effects are important in the aphid-ant interactions and that the costs for aphids of being tended by ants can vary over generations.

  20. Plant-aphid interactions: molecular and ecological perspectives.

    Science.gov (United States)

    Goggin, Fiona L

    2007-08-01

    Many aphids are major agricultural pests because of their unparalleled reproductive capacity and their ability to manipulate host plant physiology. Aphid population growth and its impact on plant fitness are strongly influenced by interactions with other organisms, including plant pathogens, endophytes, aphid endosymbionts, predators, parasitoids, ants, and other herbivores. Numerous molecular and genomic resources have recently been developed to identify sources of aphid resistance in plants, as well as potentially novel targets for control in aphids. Moreover, the same model systems that are used to explore direct molecular interactions between plants and aphids can be utilized to study the ecological context in which they occur.

  1. Thermal tolerance and resource partitioning in aphids

    Czech Academy of Sciences Publication Activity Database

    Dixon, Anthony F. G.

    XCII, - (2009), s. 171-173 ISSN 0370-4327 Institutional research plan: CEZ:AV0Z60870520 Keywords : aphids * coexistence * food quality * resource partitioning * thermal tolerance Subject RIV: EG - Zoology

  2. Long range migration of aphids into Sweden

    Science.gov (United States)

    Wiktelius, Staffan

    1984-09-01

    A five year study of migration of aphids across the southern part of the Baltic Sea is reported. The aphids were caught in a suction trap placed on a lighthouse 50 m from the shoreline. Large sections of the results are presented as case studies i.e. catches of aphids from periods containing at least three consecutive days with a southerly gradient wind. Some periods contained large and diverse catches and it is assumed that aphids regularly cross the Baltic Sea. The catches was largest on days when a cold front passed the trapping site within a period. More Myzus persicae were caught on days when the wind was southerly than on days with a northerly wind direction.

  3. Aphid Heritable Symbiont Exploits Defensive Mutualism.

    Science.gov (United States)

    Doremus, Matthew R; Oliver, Kerry M

    2017-04-15

    Insects and other animals commonly form symbioses with heritable bacteria, which can exert large influences on host biology and ecology. The pea aphid, Acyrthosiphon pisum , is a model for studying effects of infection with heritable facultative symbionts (HFS), and each of its seven common HFS species has been reported to provide resistance to biotic or abiotic stresses. However, one common HFS, called X-type, rarely occurs as a single infection in field populations and instead typically superinfects individual aphids with Hamiltonella defensa , another HFS that protects aphids against attack by parasitic wasps. Using experimental aphid lines comprised of all possible infection combinations in a uniform aphid genotype, we investigated whether the most common strain of X-type provides any of the established benefits associated with aphid HFS as a single infection or superinfection with H. defensa We found that X-type does not confer protection to any tested threats, including parasitoid wasps, fungal pathogens, or thermal stress. Instead, component fitness assays identified large costs associated with X-type infection, costs which were ameliorated in superinfected aphids. Together these findings suggest that X-type exploits the aphid/ H. defensa mutualism and is maintained primarily as a superinfection by "hitchhiking" via the mutualistic benefits provided by another HFS. Exploitative symbionts potentially restrict the functions and distributions of mutualistic symbioses with effects that extend to other community members. IMPORTANCE Maternally transmitted bacterial symbionts are widespread and can have major impacts on the biology of arthropods, including insects of medical and agricultural importance. Given that host fitness and symbiont fitness are tightly linked, inherited symbionts can spread within host populations by providing beneficial services. Many insects, however, are frequently infected with multiple heritable symbiont species, providing potential

  4. Morph matters: aggression bias in a polymorphic sparrow.

    Directory of Open Access Journals (Sweden)

    Brent M Horton

    Full Text Available In species with discrete morphs exhibiting alternative behavioral strategies, individuals may vary their aggressive behavior in competitive encounters according to the phenotype of their opponent. Such aggression bias has been documented in multiple polymorphic species evolving under negative frequency-dependent selection, but it has not been well-studied under other selection regimes. We investigated this phenomenon in white-throated sparrows (Zonotrichia albicollis, a passerine with plumage polychromatism maintained by disassortative mating. The two distinct color morphs differ with respect to reproductive strategy in that white-striped birds invest more in territorial aggression than tan-striped birds. Whether territorial aggression in this species is biased according to the morph of an intruder is less understood. We found that during peak territorial and mating activity, both color morphs and sexes can exhibit aggression bias, but whether they do so depends on the strategy (morph of the intruder. During simulated territorial intrusions, resident white-striped males and tan-striped females, which represent the opposite ends of a continuum from high to low territorial aggression, altered their territorial responses according to intruder morph. Tan-striped males and white-striped females, which represent the middle of the continuum, did not show a bias. We propose that because of the disassortative mating system and morph differences in reproductive strategy, the fitness risks of intrusions vary according to the morphs of the resident and the intruder, and that aggression bias is an attuned response to varying threats to fitness.

  5. A tale of two tails: developing an avian inspired morphing actuator for yaw control and stability.

    Science.gov (United States)

    Gamble, Lawren L; Inman, Daniel J

    2018-02-09

    Motivated by the lack of research in tailless morphing aircraft in addition to the current inability to measure the resultant aerodynamic forces and moments of bird control maneuvers, this work aims to develop and test a multi-functional morphing control surface based on the horizontal tail of birds for a low-radar-signature unmanned aerial vehicle. Customized macro fiber composite actuators were designed to achieve yaw control across a range of sideslip angles by inducing 3D curvature as a result of bending-twisting coupling, a well-known phenomenon in classical fiber composite theory. This allows for yaw control, pitch control, and limited air break control. The structural response of the customized actuators was determined numerically using both a piezoelectric and an equivalent thermal model in order to optimize the fiber direction to allow for maximized deflection in both the vertical and lateral directions. In total, three control configurations were tested experimentally: symmetric deflection for pitch control, single-sided deflection for yaw control, and antisymmetric deflection for air brake control. A Reynolds-averaged-Navier-Stokes fluid simulation was also developed to compare with the experimental results for the unactuated baseline configuration. The actuator was shown to provide better yaw control than traditional split aileron methods, remain effective in larger sideslip angles, and provide directional yaw stability when unactuated. Furthermore, it was shown to provide adequate pitch control in sideslip in addition to limited air brake capabilities. This design is proposed to provide complete aircraft control in concert with spanwise morphing wings.

  6. Morphing Planar Graph Drawings with a Polynomial Number of Steps

    DEFF Research Database (Denmark)

    Alamdari, Soroush; Angelini, Patrizio; Chan, Timothy M.

    2013-01-01

    In 1944, Cairns proved the following theorem: given any two straight-line planar drawings of a triangulation with the same outer face, there exists a morph (i.e., a continuous transformation) between the two drawings so that the drawing remains straight-line planar at all times. Cairns’s original...... proof required exponentially many morphing steps. We prove that there is a morph that consists of O(n^2) steps, where each step is a linear morph that moves each vertex at constant speed along a straight line. Using a known result on compatible triangulations this implies that for a general planar graph...... G and any two straight-line planar drawings of G with the same embedding, there is a morph between the two drawings that preserves straight-line planarity and consists of O(n^4) steps....

  7. Piezoelectric composite morphing control surfaces for unmanned aerial vehicles

    Science.gov (United States)

    Ohanian, Osgar J., III; Karni, Etan D.; Olien, Chris C.; Gustafson, Eric A.; Kochersberger, Kevin B.; Gelhausen, Paul A.; Brown, Bridget L.

    2011-04-01

    The authors have explored the use of morphing control surfaces to replace traditional servo-actuated control surfaces in UAV applications. The morphing actuation is accomplished using Macro Fiber Composite (MFC) piezoelectric actuators in a bimorph configuration to deflect the aft section of a control surface cross section. The resulting camber change produces forces and moments for vehicle control. The flexible piezoelectric actuators are damage tolerant and provide excellent bandwidth. The large amplitude morphing deflections attained in bench-top experiments demonstrate the potential for excellent control authority. Aerodynamic performance calculations using experimentally measured morphed geometries indicate changes in sectional lift coefficients that are superior to a servo-actuated hinged flap airfoil. This morphing flight control actuation technology could eliminate the need for servos and mechanical linkages in small UAVs and thereby increase reliability and reduce drag.

  8. Pyramiding different aphid-resistance genes in elite soybean germplasm to combat dynamic aphid populations

    Science.gov (United States)

    The soybean aphid, an invasive species, has posed a significant threat to soybean production in North America since 2001. Use of resistant cultivars is an effective tactic to protect soybean yield. However, the variability and dynamics of aphid populations could limit the effectiveness of host-resis...

  9. AphID (Lucid key) http://AphID.AphidNet.org

    Science.gov (United States)

    This peer-reviewed web site concentrates on the 66 adult alate and apterous aphids that are the world's most cosmopolitan and polyphagous species. The site includes fact sheets about the various aphids species, a glossary of terms helpful to the student, hundreds of photographs and illustrations, a...

  10. Adaptive pressure-controlled cellular structures for shape morphing I: design and analysis

    International Nuclear Information System (INIS)

    Luo, Quantian; Tong, Liyong

    2013-01-01

    This work investigates adaptive bio-inspired pressure cellular structures for shape morphing. Optimum designs for cellular structures with void and pressure cells are proposed and then structural analyses are conducted. In the present design, a unit cell is comprised of straight and curved walls. When compressed air is pumped into a pressure cell, the curved walls deform in bending due to the pressure difference in two adjacent cells that leads to overall structural deformation in extension. One-dimensional actuation strain up to 35% can be theoretically achieved. In part I, we present basic design concepts and cellular mechanics. Unlike conventional structural analysis for cellular structures, a statically indeterminate unit cell is considered and novel analytical formulations are derived for the present pressurized cellular structures in linear and nonlinear analyses. In part II, we will present experimental testing and finite element analysis to demonstrate the feasibility of the present pressurized cellular actuators for morphing wings and to validate the present cellular mechanics formulations. (paper)

  11. Development of a morphing structure with the incorporation of central pattern generators

    Science.gov (United States)

    Bliss, Thomas K.; Bart-Smith, Hilary; Iwasaki, Tetsuya

    2006-03-01

    The Manta Ray, Manta birostris, is an amazing creature, propelling itself through the water with the elegant and complex flapping of its wings. Achieving outstanding efficiencies, engineers are looking for ways to mimic its flight through the water and harness its propulsive techniques. This study combines two biologically inspired aspects to achieve this goal: morphing structures actuated with a biomimetic neural network control system. It is believed that this combination will prove capable of producing the oscillatory motions necessary for locomotion. In this paper, a four-truss structure with three actuators is chosen and its performance capabilities are analyzed. A synthetic central pattern generator, which provides the fundamental control mechanisms for rhythmic motion in animals, is designed to realize an oscillatory control of the three actuators. The control system is simulated using Matlab, then combined with LabVIEW to control the four-truss structure. The system's performance is analyzed, with specific attention to both transient and steady-state behavior.

  12. Aphid aerial density profiles are consistent with turbulent advection amplifying flight behaviours: abandoning the epithet ‘passive’

    Science.gov (United States)

    Reynolds, Andy M; Reynolds, Don R

    2008-01-01

    Seminal field studies led by C. G. Johnson in the 1940s and 1950s showed that aphid aerial density diminishes with height above the ground such that the linear regression coefficient, b, of log density on log height provides a single-parameter characterization of the vertical density profile. This coefficient decreases with increasing atmospheric stability, ranging from −0.27 for a fully convective boundary layer to −2.01 for a stable boundary layer. We combined a well-established Lagrangian stochastic model of atmospheric dispersal with simple models of aphid behaviour in order to account for the range of aerial density profiles. We show that these density distributions are consistent with the aphids producing just enough lift to become neutrally buoyant when they are in updraughts and ceasing to produce lift when they are in downdraughts. This active flight behaviour in a weak flier is thus distinctly different from the aerial dispersal of seeds and wingless arthropods, which is passive once these organisms have launched into the air. The novel findings from the model indicate that the epithet ‘passive’ often applied to the windborne migration of small winged insects is misleading and should be abandoned. The implications for the distances traversed by migrating aphids under various boundary-layer conditions are outlined. PMID:18782743

  13. The more-or-less morphing face illusion: A case of fixation-dependent modulation

    NARCIS (Netherlands)

    Lier, R.J. van; Koning, A.R.

    2014-01-01

    A visual illusion is presented in which the perceived changes in a morphing sequence depend on eye movements. The phenomenon is illustrated using face morphs: when tracking a moving dot superimposed on a face morphing sequence, the changes in the morphing sequence seem rather small, but when the dot

  14. Community-wide impact of an exotic aphid on introduced tall goldenrod

    OpenAIRE

    ANDO, YOSHINO; UTSUMI, SHUNSUKE; OHGUSHI, TAKAYUKI

    2011-01-01

    1. The aphid Uroleucon nigrotuberculatum Olive, which is specialised to the tall goldenrod, Solidago altissima L., in its native range, has become a dominant species on the introduced tall goldenrod in Japan. How this exotic aphid influenced arthropod communities on the introduced tall goldenrod in aphid-present (spring) and aphid-absent (autumn) seasons was examined, using an aphid removal experiment. 2. In spring, aphid presence increased ant abundance because aphid honeydew attracted forag...

  15. Host plant resistance to aphids in cultivated crops: genetic and molecular bases, and interactions with aphid populations.

    Science.gov (United States)

    Dogimont, Catherine; Bendahmane, Abdelhafid; Chovelon, Véronique; Boissot, Nathalie

    2010-01-01

    Host plant resistance is an efficient and environmentally friendly means of controlling insects, including aphids, but resistant-breaking biotypes have occurred in several plant-aphid systems. Our review of the genetic and molecular bases of aphid resistance in crop species emphasizes the limited number of aphid resistance genes and alleles. Inheritance of aphid resistance may be monogenic (dominant or recessive genes) or polygenic. Two dominant, aphid resistance genes have been isolated to date. They both encode NBS-LRR proteins involved in the specific recognition of aphids. Strategies to ensure aphid resistance effectiveness and durability are discussed. Innovative research activities are proposed. Copyright 2010 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  16. Morphing of geometric composites via residual swelling.

    Science.gov (United States)

    Pezzulla, Matteo; Shillig, Steven A; Nardinocchi, Paola; Holmes, Douglas P

    2015-08-07

    Understanding and controlling the shape of thin, soft objects has been the focus of significant research efforts among physicists, biologists, and engineers in the last decade. These studies aim to utilize advanced materials in novel, adaptive ways such as fabricating smart actuators or mimicking living tissues. Here, we present the controlled growth-like morphing of 2D sheets into 3D shapes by preparing geometric composite structures that deform by residual swelling. The morphing of these geometric composites is dictated by both swelling and geometry, with diffusion controlling the swelling-induced actuation, and geometric confinement dictating the structure's deformed shape. Building on a simple mechanical analog, we present an analytical model that quantitatively describes how the Gaussian and mean curvatures of a thin disk are affected by the interplay among geometry, mechanics, and swelling. This model is in excellent agreement with our experiments and numerics. We show that the dynamics of residual swelling is dictated by a competition between two characteristic diffusive length scales governed by geometry. Our results provide the first 2D analog of Timoshenko's classical formula for the thermal bending of bimetallic beams - our generalization explains how the Gaussian curvature of a 2D geometric composite is affected by geometry and elasticity. The understanding conferred by these results suggests that the controlled shaping of geometric composites may provide a simple complement to traditional manufacturing techniques.

  17. Ability of systemic insecticide dimethoate to prevent aphid ...

    African Journals Online (AJOL)

    Weekly collection of aphids at both sites showcrl a predominance of Myzus persicae (Sul.), the principle vector of most potato viruses. Dimethoate controlled aphids at Kalengyere but not at Namulonge. As a result, seed potatoes obtained from Kalengyere and grown at Namulonge acquired the aphid-transmitled PLRV in ...

  18. Whitefly and aphid inducible promoters of Arabidopsis thaliana L.

    Indian Academy of Sciences (India)

    NEERAJ KUMAR DUBEY

    2018-02-16

    Feb 16, 2018 ... After 2, 24, 48, 72 and 96 h of aphid infesta- tion, aphids were removed with a fine brush and the leaves were used for RNA isolation. For aphid (M. nicotinae) infestation treatment of the T2 transgenic tobacco plant, leaf disks of a 10-mm diameter were cut, transferred to agar plate, and challenged with.

  19. Loss of aphid transmissibility of plum pox virus isolates

    NARCIS (Netherlands)

    Kamenova, I.; Lohuis, H.; Peters, D.

    2002-01-01

    The aphid transmissibility of seven Plum pox virus (PPV) isolates and the amino acid sequences of their coat proteins were analysed Two aphid transmissible isolates PPV-A and PPV-P contained the DAG amino triplet, while DAL or NAG replaced this triplet in the coat proteins of non-aphid transmissible

  20. Cannibalistic-morph Tiger Salamanders in unexpected ecological contexts

    Science.gov (United States)

    McLean, Kyle I.; Stockwell, Craig A.; Mushet, David M.

    2016-01-01

    Barred tiger salamanders [Ambystoma mavortium (Baird, 1850)] exhibit two trophic morphologies; a typical and a cannibalistic morph. Cannibalistic morphs, distinguished by enlarged vomerine teeth, wide heads, slender bodies, and cannibalistic tendencies, are often found where conspecifics occur at high density. During 2012 and 2013, 162 North Dakota wetlands and lakes were sampled for salamanders. Fifty-one contained A. mavortium populations; four of these contained cannibalistic morph individuals. Two populations with cannibalistic morphs occurred at sites with high abundances of conspecifics. However, the other two populations occurred at sites with unexpectedly low conspecific but high fathead minnow [Pimephales promelas (Rafinesque, 1820)] abundances. Further, no typical morphs were observed in either of these later two populations, contrasting with earlier research suggesting cannibalistic morphs only occur at low frequencies in salamander populations. Another anomaly of all four populations was the occurrence of cannibalistic morphs in permanent water sites, suggesting their presence was due to factors other than faster growth allowing them to occupy ephemeral habitats. Therefore, our findings suggest environmental factors inducing the cannibalistic morphism may be more complex than previously thought.

  1. The more-or-less morphing face illusion: a case of fixation-dependent modulation.

    Science.gov (United States)

    Van Lier, Rob; Koning, Arno

    2014-01-01

    A visual illusion is presented in which the perceived changes in a morphing sequence depend on eye movements. The phenomenon is illustrated using face morphs: when tracking a moving dot superimposed on a face morphing sequence, the changes in the morphing sequence seem rather small, but when the dot stops moving, the perceived extent of morphing suddenly becomes much larger. We explore this phenomenon further and discuss the observed effects.

  2. Root-lesion nematodes suppress cabbage aphid population development by reducing aphid daily reproduction

    Directory of Open Access Journals (Sweden)

    W. H. Gera eHol

    2016-02-01

    Full Text Available Empirical studies have shown that belowground feeding herbivores can affect the performance of aboveground herbivores in different ways. Often the critical life-history parameters underlying the observed performance effects remain unexplored. In order to better understand the cause for the observed effects on aboveground herbivores, these ecological mechanisms must be better understood. In this study we combined empirical experiments with a modelling approach to analyse the effect of two root feeding endoparasitic nematodes with different feeding strategies on the population growth of the aboveground feeding specialist aphid Brevicoryne brassicae on Brassica nigra. The aim was to test whether emerging differences in life history characteristics (days until reproduction, daily reproduction would be sufficient to explain observed differences in aphid population development on plants with and without two species of nematodes. Aphid numbers were lower on plants with Pratylenchus penetrans in comparison to aphid numbers on plants with Meloidogyne spp. A dedicated experiment showed that aphid daily reproduction was lower on plants with P. penetrans (3.08 offspring per female per day in comparison to both uninfested plants and plants with Meloidogyne spp. (3.50 offspring per female per day. The species-specific reduction of aphid reproduction appeared independent of changes in amino acids, soluble sugars or the glucosinolate sinigrin in the phloem. An individual-based model revealed that relatively small differences in reproduction rate per female were sufficient to yield a similar difference in aphid populations as was found in the empirical experiments.

  3. Thiamine treatments alleviate aphid infestations in barley and pea.

    Science.gov (United States)

    Hamada, Afaf M; Jonsson, Lisbeth M V

    2013-10-01

    Treatment of plants with thiamine (Vitamin B1) has before been shown to activate plant defence against microorganisms. Here, we have studied the effects of thiamine treatments of plants on aphid reproduction and behaviour. The work was mainly carried out with bird cherry-oat aphid (Rhopalosiphum padi L.) on barley (Hordeum vulgare L.). Aphid population growth and aphid acceptance on plants grown from seeds soaked in a 150μM thiamine solution were reduced to ca. 60% of that on control plants. R. padi life span and the total number of offspring were reduced on barley plants treated with thiamine. Healthy aphids and aphids infected with the R. padi virus were similarly affected. Spraying or addition of thiamine at 150μM to nutrient solutions likewise resulted in reduced aphid population growth to ca. 60%, as did plant exposure to thiamine odour at 4mM. Thiamine treatments resulted in reduced aphid population growth also when tested with grain aphid (Sitobion avenae F.) on barley and pea aphid (Acyrthosiphon pisum H.) on pea (Pisum sativum L.). There was no direct effect of thiamine on aphid reproduction or thiamine odour on aphid behaviour, as evaluated using artificial diets and by olfactometer tests, respectively. Two gene sequences regulated by salicylic acid showed higher transcript abundance and one gene sequence regulated by methyl jasmonate showed lower transcript abundance in thiamine-treated plants but not in control plants after aphid infestation. These results suggest that the aphid antibiosis and antixenosis effects may be related to priming of defence, but more studies are needed to explain the effects against aphids. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. An Image Morphing Technique Based on Optimal Mass Preserving Mapping

    Science.gov (United States)

    Zhu, Lei; Yang, Yan; Haker, Steven; Tannenbaum, Allen

    2013-01-01

    Image morphing, or image interpolation in the time domain, deals with the metamorphosis of one image into another. In this paper, a new class of image morphing algorithms is proposed based on the theory of optimal mass transport. The L2 mass moving energy functional is modified by adding an intensity penalizing term, in order to reduce the undesired double exposure effect. It is an intensity-based approach and, thus, is parameter free. The optimal warping function is computed using an iterative gradient descent approach. This proposed morphing method is also extended to doubly connected domains using a harmonic parameterization technique, along with finite-element methods. PMID:17547128

  5. Laser-assisted morphing of complex three dimensional objects.

    Science.gov (United States)

    Drs, Jakub; Kishi, Tetsuo; Bellouard, Yves

    2015-06-29

    Morphing refers to the smooth transition from a specific shape into another one, in which the initial and final shapes can be significantly different. A typical illustration is to turn a cube into a sphere by continuous change of shape curvatures. Here, we demonstrate a process of laser-induced morphing, driven by surface tension and thermally-controlled viscosity. As a proof-of-concept, we turn 3D glass structures fabricated by a femtosecond laser into other shapes by locally heating up the structure with a feedback-controlled CO2 laser. We further show that this laser morphing process can be accurately modelled and predicted.

  6. Implementasi Teknik Mesh Morphing Dan Selection Morphing Pada Citra Digital Dengan Delphi 7.0

    OpenAIRE

    Pribadi, Oki Dhian; adi sarwoko, eko

    2013-01-01

    Dalam pembuatan sebuah film, ada banyak jenis spesial efek yang ditambahkan ke dalam sebuah film untuk menghasilkan suatu film yang berkualitas. Salah satu spesial efek yang sering digunakan adalah morphing, yaitu suatu efek dimana suatu obyek diubah perlahan-lahan menjadi obyek lain. Sebelum menggunakan komputer, efek ini dilakukan dengan cara tradisional yang sulit dan memakan waktu lama dalam pembuatannya dengan hasil yang kurang memuaskan, dengan menggunakan komputer selain waktu pembuata...

  7. Improvement of wheat for resistance to Russian Wheat Aphid

    International Nuclear Information System (INIS)

    Kinyua, M.; Malinga, J.N.; Wanyama, J.; Karanja, L.; Njau, P.; Leo, T.; Alomba, E.

    2001-01-01

    Breeding for resistance against Russian wheat aphid in Kenya is reported. Results of six of the lines were found to have high to moderate resistance to Russian wheat aphid. Popular lines were susceptible in the greenhouse when subjected to aphid pressure but showed moderate susceptibility when screened under field conditions, indicating that in years or location with low aphid pressure farmers may still get a crop. However in areas of high aphid pressure or bad years they may lose their crop. Consequently, developing resistant/torerant varieties is urgent

  8. Effects of aposymbiotic and symbiotic aphids on parasitoid progeny development and adult oviposition behavior within aphid instars.

    Science.gov (United States)

    Cheng, Rui-Xia; Meng, Ling; Li, Bao-Ping

    2010-04-01

    This study aims at exploring the potential relationship between aphidiine parasitoid development and the primary endosymbiont in aphids by focusing on specific aphid instars and the relative effects on parasitoid oviposition behavior and progeny development. Lysiphlebus ambiguus (Aphidiidae, Hymenoptera) is a solitary parasitoid of several species of aphids, including Aphis fabae. In this study, A. fabae was treated with antibiotic rifampicin to obtain aposymbiotic hosts and exposed to parasitism. L. ambiguus launched significantly more attacks on symbiotic L(2) (the second instar), aposymbiotic L(3) (the third instar) and L(4) (the forth instar) hosts than on the corresponding hosts at the same age. L. ambiguus also parasitized more L(1) aphids compared with adults irrespective of whether the aphid was asymbiotic or not. Pupa mortality rate of parasitoid progeny was significantly lower from aposymbiotic hosts than from the corresponding symbiotics at all stages. Female-biased parasitoid progeny was produced from aposymbiotic aphids without respect to host ages, but female progeny increased linearly with host ages at parasitism from symbiotic aphids. Body size of parasitoid progeny increased linearly with host instars at parasitism in symbiotic aphids but did not significantly change across host instars in aposymbiotic aphids. The offspring parasitoids turned out to be generally large in body size from attacking aposymbiotic aphids compared with the symbiotics. Development time of egg-to-adult of parasitoid progeny decreased with host instars in both symbiotic and aposymbiotic aphids but was generally much longer in aposymbiotic aphids than in symbiotic aphids. Our study suggests that age or body size of host aphids may not be the only cue exercised by L. ambiguus to evaluate host quality and that offspring parasitoids may be able to compensate for the nutrition stress associated with disruption of primary endosymbiotc bacteria in aposymbiotic aphids.

  9. Manipulation of parasitoids for aphid pest management: progress and prospects.

    Science.gov (United States)

    Powell, Wilf; Pickett, John A

    2003-02-01

    This paper describes research at IACR-Rothamsted on aphid parasitoid responses to semiochemical foraging stimuli, aimed at developing novel ways of manipulating these behaviours to overcome ecological constraints to biological and integrated pest control. Female parasitoids respond both to aphid sex pheromones acting as kairomones, and to aphid-induced plant volatiles, acting as synomones. A range of economically important parasitoid species respond to aphid sex pheromones, and their potential for enhancing parasitization of aphid populations has been demonstrated in the field. Commercial production of the pheromone from the plant Nepeta cataria L has been developed and strategies for its use in arable crops are being investigated. Aphid-induced plant volatiles are released systemically throughout the plant and are aphid species specific, probably induced by elicitors in aphid saliva. Aphid-infested plants can induce uninfested neighbours to release damage-related volatiles, plant-to-plant communication occurring via the rhizosphere. The plant compound cis-jasmone has been identified as a plant signal with potential for aphid control, inducing plant defence mechanisms that both deter colonising aphids and attract parasitoids and predators. Such compounds may represent a new generation of crop protectants and their further investigation and development will be aided by the tools generated by genomic and post-genomic biology.

  10. Partial aphid resistance in lettuce negatively affects parasitoids.

    Science.gov (United States)

    Lanteigne, Marie-Eve; Brodeur, Jacques; Jenni, Sylvie; Boivin, Guy

    2014-10-01

    This study investigated the effects of partial plant resistance on the lettuce aphid Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae), a major pest of cultivated lettuce (Lactuca sativa L.), and one of its parasitoids, Aphidius ervi Haliday (Hymenoptera: Braconidae). Aphids were reared on susceptible (L. sativa variety Estival; S) or partially resistant (Lactuca serriola L. PI 491093; PR) lettuce, and next parasitized by A. ervi females. Fitness proxies were measured for both aphids and parasitoids. Developmental time to adult stage took longer for alate and apterous aphids (an average of 3.5 and 1.5 additional days, respectively) on PR than on S lettuce, and fecundity of alate aphids reared on PR lettuce was reduced by 37.8% relative to those reared on S lettuce. Size (tibia length) and weight of aphids reared on PR lettuce were lower than for aphids reared on S lettuce from the third and second instar onward, respectively. Parasitism of aphids reared on PR plants resulted in lower parasitoid offspring emergence (-49.9%), lower adult female (-30.3%) and male (-27.5%) weight, smaller adult female (-17.5%) and male (-11.9%) size, and lower female fecundity (37.8% fewer eggs) than when parasitoids developed from aphids reared on S plants. Our results demonstrate that partial aphid resistance in lettuce negatively affects both the second and third trophic levels. Host plant resistance in cultivated lettuce may therefore create an ecological sink for aphid parasitoids.

  11. Morphing images to demonstrate potential surgical outcomes.

    Science.gov (United States)

    Hamilton, Grant S

    2010-05-01

    Morphing patient images to offer some demonstration of the intended surgical outcome can support shared expectations between patient and facial plastic surgeon. As part of the preoperative consultation, showing a patient an image that compares their face before surgery with what is planned after surgery can greatly enhance the surgical experience. This article refers to use of Photoshop CS3 for tutorial descriptions but any recent version of Photoshop is sufficiently similar. Among the topics covered are creating a before-and-after, rhinoplasty imaging, face- and brow-lift imaging, and removing wrinkles. Each section presents a step-by-step tutorial with graphic images demonstrating the computer screen and Photoshop tools. Copyright 2010 Elsevier Inc. All rights reserved.

  12. Flow morphing by coaxial type plasma actuator

    Science.gov (United States)

    Toyoizumi, S.; Aono, H.; Ishikawa, H.

    2017-04-01

    The purpose of study is to achieve the fluid drag reduction of a circular disk by Dielectric Barrier Discharge Plasma Actuator (DBD-PA). We here introduced “Flow Morphing” concept that flow around the body was changed by DBD-PA jet, such as the body shape morphing. Coaxial type DBD-PA injected axisymmetric jet, generating the vortex region on the pressure side of the circular disk. The vortex generated by axisymmetric plasma jet and flow around circular disk were visualized by tracer particles method. The fluid drag was measured by compression type load cell. In addition streamwise velocity was measured by an X-type hot wire probe. The extent of fluid drag reduction by coaxial type DBD-PA jet was influenced by the volume of vortex region and the diameter of plasma electrode.

  13. Comments on prospects of fully adaptive aircraft wings

    Science.gov (United States)

    Inman, Daniel J.; Gern, Frank H.; Robertshaw, Harry H.; Kapania, Rakesh K.; Pettit, Greg; Natarajan, Anand; Sulaeman, Erwin

    2001-06-01

    New generations of highly maneuverable aircraft, such as Uninhabited Combat Air Vehicles (UCAV) or Micro Air Vehicles (MAV) are likely to feature very flexible lifting surfaces. To enhance stealth properties and performance, the replacement of hinged control surfaces by smart wings and morphing airfoils is investigated. This requires a fundamental understanding of the interaction between aerodynamics, structures, and control systems. The goal is to build a model consistent with distributed control and to exercise this model to determine the progress possible in terms of flight control (lift, drag and maneuver performance) with an adaptive wing. Different modeling levels are examined and combined with a variety of distributed control approaches to determine what types of maneuvers and flight regimes may be possible. This paper describes the current progress of the project and highlights some recent findings.

  14. AVST Morphing Project Research Summaries in Fiscal Year 2001

    Science.gov (United States)

    McGowan, Anna-Maria R.

    2002-01-01

    The Morphing project at the National Aeronautics and Space Agency's Langley Research Center is part of the Aerospace Vehicle Systems Program Office that conducts fundamental research on advanced technologies for future flight vehicles. The objectives of the Morphing project are to develop and assess advanced technologies and integrated component concepts to enable efficient, multi-point adaptability in air and space vehicles. In the context of the project, the word "morphing" is defined as "efficient, multi-point adaptability" and may include micro or macro, structural or fluidic approaches. The current document on the Morphing project is a compilation of research summaries and other information on the project from fiscal year 2001. The focus of this document is to provide a brief overview of the project content, technical results and lessons learned from fiscal year 2001.

  15. Morph Scenarios for the Integrated Radar-Tracker

    National Research Council Canada - National Science Library

    Lebak, J. M; Coate, W. G

    2005-01-01

    The DARPA-sponsored Polymorphous Computing Architectures (PCA) program is developing advanced computer architectures that have the capacity to adapt, or morph, to obtain better performance on specific problems...

  16. Morphing Flight Control Surface for Advanced Flight Performance, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In this SBIR project, a new Morphing Flight Control Surface (MFCS) will be developed. The distinction of the research effort is that the SenAnTech team will employ...

  17. A Data-Driven Approach to Realistic Shape Morphing

    KAUST Repository

    Gao, Lin

    2013-05-01

    Morphing between 3D objects is a fundamental technique in computer graphics. Traditional methods of shape morphing focus on establishing meaningful correspondences and finding smooth interpolation between shapes. Such methods however only take geometric information as input and thus cannot in general avoid producing unnatural interpolation, in particular for large-scale deformations. This paper proposes a novel data-driven approach for shape morphing. Given a database with various models belonging to the same category, we treat them as data samples in the plausible deformation space. These models are then clustered to form local shape spaces of plausible deformations. We use a simple metric to reasonably represent the closeness between pairs of models. Given source and target models, the morphing problem is casted as a global optimization problem of finding a minimal distance path within the local shape spaces connecting these models. Under the guidance of intermediate models in the path, an extended as-rigid-as-possible interpolation is used to produce the final morphing. By exploiting the knowledge of plausible models, our approach produces realistic morphing for challenging cases as demonstrated by various examples in the paper. © 2013 The Eurographics Association and Blackwell Publishing Ltd.

  18. Plant-aphid interactions under elevated CO2: some cues from aphid feeding behavior

    Directory of Open Access Journals (Sweden)

    Yu-Cheng eSun

    2016-04-01

    Full Text Available Although the increasing concentration of atmospheric carbon dioxide (CO2 accelerates the accumulation of carbohydrates and increases the biomass and yield of C3 crop plants, it also reduces their nitrogen status. The consequent changes in primary and secondary metabolites affect the palatability of host plants and the feeding of herbivorous insects. Aphids are phloem feeders and are considered the only feeding guild that positively responds to elevated CO2. In this review, we consider how elevated CO2 modifies host defenses, nutrients, and water-use efficiency by altering concentrations of the phytohormones jasmonic acid, salicylic acid, ethylene, and abscisic acid. We will describe how these elevated CO2-induced changes in defenses, nutrients, and water status facilitate specific stages of aphid feeding, including penetration, phloem-feeding, and xylem absorption. We conclude that a better understanding of the effects of elevated CO2 on aphids and on aphid damage to crop plants will require research on the molecular aspects of the interaction between plant and aphid but also research on aphid interactions with their intra- and inter-specific competitors and with their natural enemies.

  19. Angiotensin-converting enzymes modulate aphid-plant interactions.

    Science.gov (United States)

    Wang, Wei; Luo, Lan; Lu, Hong; Chen, Shaoliang; Kang, Le; Cui, Feng

    2015-03-06

    Angiotensin-converting enzymes (ACEs) are key components of the renin-angiotensin system in mammals. However, the function of ACE homologs in insect saliva is unclear. Aphids presumably deliver effector proteins via saliva into plant cells to maintain a compatible insect-plant interaction. In this study, we showed that ACE modulates aphid-plant interactions by affecting feeding behavior and survival of aphids on host plants. Three ACE genes were identified from the pea aphid Acyrthosiphon pisum genome. ACE1 and ACE2 were highly expressed in the salivary glands and are predicted to function as secretory proteins. The ACE2 transcript level decreased in aphids fed on artificial diet compared with aphids fed on Vicia faba. The knockdown of the expression of each ACE by RNAi failed to affect aphid survival. When ACE1 and ACE2 were simultaneously knocked down, aphid feeding was enhanced. Aphids required less time to find the phloem sap and showed longer passive ingestion. However, the simultaneous knockdown of ACE1 and ACE2 resulted in a higher mortality rate than the control group when aphids were fed on plants. These results indicated that ACE1 and ACE2 function together to modulate A. pisum feeding and survival on plants.

  20. Chemical Ecology and Sociality in Aphids: Opportunities and Directions.

    Science.gov (United States)

    Abbot, Patrick; Tooker, John; Lawson, Sarah P

    2018-04-10

    Aphids have long been recognized as good phytochemists. They are small sap-feeding plant herbivores with complex life cycles that can involve cyclical parthenogenesis and seasonal host plant alternation, and most are plant specialists. Aphids have distinctive traits for identifying and exploiting their host plants, including the expression of polyphenisms, a form of discrete phenotypic plasticity characteristic of insects, but taken to extreme in aphids. In a relatively small number of species, a social polyphenism occurs, involving sub-adult "soldiers" that are behaviorally or morphologically specialized to defend their nestmates from predators. Soldiers are sterile in many species, constituting a form of eusociality and reproductive division of labor that bears striking resemblances with other social insects. Despite a wealth of knowledge about the chemical ecology of non-social aphids and their phytophagous lifestyles, the molecular and chemoecological mechanisms involved in social polyphenisms in aphids are poorly understood. We provide a brief primer on aspects of aphid life cycles and chemical ecology for the non-specialists, and an overview of the social biology of aphids, with special attention to chemoecological perspectives. We discuss some of our own efforts to characterize how host plant chemistry may shape social traits in aphids. As good phytochemists, social aphids provide a bridge between the study of insect social evolution sociality, and the chemical ecology of plant-insect interactions. Aphids provide many promising opportunities for the study of sociality in insects, and to understand both the convergent and novel traits that characterize complex sociality on plants.

  1. Mechanisms and evolution of plant resistance to aphids.

    Science.gov (United States)

    Züst, Tobias; Agrawal, Anurag A

    2016-01-06

    Aphids are important herbivores of both wild and cultivated plants. Plants rely on unique mechanisms of recognition, signalling and defence to cope with the specialized mode of phloem feeding by aphids. Aspects of the molecular mechanisms underlying aphid-plant interactions are beginning to be understood. Recent advances include the identification of aphid salivary proteins involved in host plant manipulation, and plant receptors involved in aphid recognition. However, a complete picture of aphid-plant interactions requires consideration of the ecological outcome of these mechanisms in nature, and the evolutionary processes that shaped them. Here we identify general patterns of resistance, with a special focus on recognition, phytohormonal signalling, secondary metabolites and induction of plant resistance. We discuss how host specialization can enable aphids to co-opt both the phytohormonal responses and defensive compounds of plants for their own benefit at a local scale. In response, systemically induced resistance in plants is common and often involves targeted responses to specific aphid species or even genotypes. As co-evolutionary adaptation between plants and aphids is ongoing, the stealthy nature of aphid feeding makes both the mechanisms and outcomes of these interactions highly distinct from those of other herbivore-plant interactions.

  2. Mechanisms Underlying the Nonconsumptive Effects of Parasitoid Wasps on Aphids.

    Science.gov (United States)

    Ingerslew, K S; Finke, D L

    2017-02-01

    Natural enemies need not consume herbivores to suppress herbivore populations. Behavioral interactions can adversely impact herbivore fitness from reduced time feeding, investment in defense, or injury from failed attacks. The importance of such "nonconsumptive effects" for herbivore suppression may vary across species based on the specificity and intensity of the herbivore defensive response. In a series of manipulative studies, we quantified the nature and consequences of nonconsumptive interactions between two parasitoid wasps, Aphidius ervi Haliday and Aphidius colemani Viereck, on two aphid species, pea aphids (Acyrthosiphon pisum (Harris)) and green peach aphids (Myzus persicae (Sulzer)). Both wasps successfully parasitize green peach aphids, but only A. ervi parasitizes pea aphids. We observed A. ervi antennating and stinging pea aphids and documented a decrease in pea aphid longevity in response to stinging even when the aphid survived the interaction and no mummy formed. The primary defensive tactic of pea aphids in response to either wasp species was dropping from the host plant. Both wasp species antennated and stung green peach aphids, but they elicited unique defensive behaviors. Green peach aphids kicked or emitted cornicle secretions in response to A. colemani but spent more time off the plant in the presence of A. ervi. Green peach aphid longevity and fecundity were not affected by wasp stings when the aphid survived and no mummy formed. Our study demonstrates the complexity of behavioral interactions between parasitoids and their potential hosts and contributes to a mechanistic understanding of variation in the nonconsumptive suppression of herbivore populations. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Preliminary Aerodynamic Investigation of Fan Rotor Blade Morphing

    Science.gov (United States)

    Tweedt, Daniel L.

    2012-01-01

    Various new technologies currently under development may enable controlled blade shape variability, or so-called blade morphing, to be practically employed in aircraft engine fans and compressors in the foreseeable future. The current study is a relatively brief, preliminary computational fluid dynamics investigation aimed at partially demonstrating and quantifying the aerodynamic potential of fan rotor blade morphing. The investigation is intended to provide information useful for near-term planning, as well as aerodynamic solution data sets that can be subsequently analyzed using advanced acoustic diagnostic tools, for the purpose of making fan noise comparisons. Two existing fan system models serve as baselines for the investigation: the Advanced Ducted Propulsor fan with a design tip speed of 806 ft/sec and a pressure ratio of 1.294, and the Source Diagnostic Test fan with a design tip speed of 1215 ft/sec and a pressure ratio of 1.470. Both are 22-in. sub-scale, low-noise research fan/nacelle models that have undergone extensive experimental testing in the 9- by 15-foot Low Speed Wind Tunnel at the NASA Glenn Research Center. The study, restricted to fan rotor blade morphing only, involves a fairly simple blade morphing technique. Specifically, spanwise-linear variations in rotor blade-section setting angle are applied to alter the blade shape; that is, the blade is linearly retwisted from hub to tip. Aerodynamic performance comparisons are made between morphed-blade and corresponding baseline configurations on the basis of equal fan system thrust, where rotor rotational speed for the morphed-blade fan is varied to change the thrust level for that configuration. The results of the investigation confirm that rotor blade morphing could be a useful technology, with the potential to enable significant improvements in fan aerodynamic performance. Even though the study is very limited in scope and confined to simple geometric perturbations of two existing fan

  4. Comparative transcriptomic analyses revealed divergences of two agriculturally important aphid species

    OpenAIRE

    Wang, Dahai; Liu, Qi; Jones, Huw D; Bruce, Toby; Xia, Lanqin

    2014-01-01

    Background Grain aphid (Sitobion avenae F) and pea aphid (Acyrthosiphon pisum) are two agriculturally important pest species, which cause significant yield losses to crop plants each year by inflicting damage both through the direct effects of feeding and by vectoring debilitating plant viruses. Although a close phylogenetic relationship between grain aphid and pea aphid was proposed, the biological variations between these two aphid species are obvious. While the host ranges of grain aphid i...

  5. Trial to control woolly aphid by earwigs

    OpenAIRE

    Trautmann, Martin; Scheer, Christian

    2006-01-01

    In years of disadvantageous atmospheric conditions natural control of woolly aphid by its parasite A. mali is insufficient in the majority of cases. In organic fruit-growing a chemical control is not possible. Settlements of earwigs showed a complete and lasting control of the pest in the year of testing, 2005. Fruitdamages were not found.

  6. Aphid (Hemiptera: Aphididae) species determined on herbaceous ...

    African Journals Online (AJOL)

    This study aimed to find out the Aphidoidea species feeding on herbaceous and shrub plants of Bartýn province. As a result, total of 28 aphid species belonging to 14 genus and 4 tribes of the super family Aphidoidea were determined. Of these determined species, Aphis fabae Scopoli, Aphis farinosa J. F. Gmelin, Aphis ...

  7. Pathogenicity of conidia-based preparations of entomopathogenic fungi against the greenhouse pest aphids: green peach aphid, melon aphid, and foxglove aphid

    Science.gov (United States)

    Seeking new isolates of entomopathogenic fungi with greater virulence against greenhouse aphid pests than those currently registered in North America for control of these insects, single-dose screening assays of 44 selected fungal isolates and 4 commercially available strains were conducted against ...

  8. Aphid parasitoids (Hymenoptera, Braconidae, Aphidiinae) from Thailand

    Czech Academy of Sciences Publication Activity Database

    Starý, Petr; Rakhshani, E.; Tomanović, Ž.; Kavallieratos, N. G.; Sharkey, M.

    -, č. 2498 (2010), s. 47-52 ISSN 1175-5326 Grant - others:Ministry of Science of the Republic of Serbia(CS) 143006B; U. S. National Science Foundation(US) DEB 0542864 Institutional research plan: CEZ:AV0Z50070508 Keywords : aphids * parasitoids * biodiversity Subject RIV: EG - Zoology Impact factor: 0.853, year: 2010

  9. Aphid egg protection by ants: a novel aspect of the mutualism between the tree-feeding aphid Stomaphis hirukawai and its attendant ant Lasius productus

    Science.gov (United States)

    Matsuura, Kenji; Yashiro, Toshihisa

    2006-10-01

    Aphids often form mutualistic associations with ants, in which the aphids provide the ants with honeydew and the ants defend the aphids from predators. In this paper, we report aphid egg protection by ants as a novel aspect of the deeply interdependent relationship between a tree-feeding aphid and its attendant ant. The ant Lasius productus harbours oviparous females, males, and eggs of the hinoki cypress-feeding aphid Stomaphis hirukawai in its nests in winter. We investigated the behaviour of ants kept with aphid eggs in petri dishes to examine whether the ants recognise the aphid eggs and tend them or only provide a refuge for the aphids. Workers carried almost all of the aphid eggs into the nest within 24 h. The ants indiscriminately tended aphid eggs collected from their own colonies and those from other ant colonies. The ants cleaned the eggs and piled them up in the nest, and egg tending by ants dramatically increased aphid egg survival rates. Starving the ants showed no significant effect on aphid egg survivorship. Without ants, aphid eggs were rapidly killed by fungi. These results suggested that grooming by the ants protected the aphid eggs, at least, against pathogenic fungi. This hygienic service afforded by the ants seems indispensable for egg survival of these aphids in an environment rich in potentially pathogenic microorganisms.

  10. Model morphing and sequence assignment after molecular replacement

    International Nuclear Information System (INIS)

    Terwilliger, Thomas C.; Read, Randy J.; Adams, Paul D.; Brunger, Axel T.; Afonine, Pavel V.; Hung, Li-Wei

    2013-01-01

    A procedure for model building is described that combines morphing a model to match a density map, trimming the morphed model and aligning the model to a sequence. A procedure termed ‘morphing’ for improving a model after it has been placed in the crystallographic cell by molecular replacement has recently been developed. Morphing consists of applying a smooth deformation to a model to make it match an electron-density map more closely. Morphing does not change the identities of the residues in the chain, only their coordinates. Consequently, if the true structure differs from the working model by containing different residues, these differences cannot be corrected by morphing. Here, a procedure that helps to address this limitation is described. The goal of the procedure is to obtain a relatively complete model that has accurate main-chain atomic positions and residues that are correctly assigned to the sequence. Residues in a morphed model that do not match the electron-density map are removed. Each segment of the resulting trimmed morphed model is then assigned to the sequence of the molecule using information about the connectivity of the chains from the working model and from connections that can be identified from the electron-density map. The procedure was tested by application to a recently determined structure at a resolution of 3.2 Å and was found to increase the number of correctly identified residues in this structure from the 88 obtained using phenix.resolve sequence assignment alone (Terwilliger, 2003 ▶) to 247 of a possible 359. Additionally, the procedure was tested by application to a series of templates with sequence identities to a target structure ranging between 7 and 36%. The mean fraction of correctly identified residues in these cases was increased from 33% using phenix.resolve sequence assignment to 47% using the current procedure. The procedure is simple to apply and is available in the Phenix software package

  11. Model morphing and sequence assignment after molecular replacement

    Energy Technology Data Exchange (ETDEWEB)

    Terwilliger, Thomas C., E-mail: terwilliger@lanl.gov [Los Alamos National Laboratory, Mail Stop M888, Los Alamos, NM 87545 (United States); Read, Randy J. [University of Cambridge, Cambridge Institute for Medical Research, Cambridge CB2 0XY (United Kingdom); Adams, Paul D. [Lawrence Berkeley National Laboratory, One Cyclotron Road, Bldg 64R0121, Berkeley, CA 94720 (United States); Brunger, Axel T. [Stanford University, 318 Campus Drive West, Stanford, CA 94305 (United States); Afonine, Pavel V. [Lawrence Berkeley National Laboratory, One Cyclotron Road, Bldg 64R0121, Berkeley, CA 94720 (United States); Hung, Li-Wei [Los Alamos National Laboratory, Mail Stop M888, Los Alamos, NM 87545 (United States)

    2013-11-01

    A procedure for model building is described that combines morphing a model to match a density map, trimming the morphed model and aligning the model to a sequence. A procedure termed ‘morphing’ for improving a model after it has been placed in the crystallographic cell by molecular replacement has recently been developed. Morphing consists of applying a smooth deformation to a model to make it match an electron-density map more closely. Morphing does not change the identities of the residues in the chain, only their coordinates. Consequently, if the true structure differs from the working model by containing different residues, these differences cannot be corrected by morphing. Here, a procedure that helps to address this limitation is described. The goal of the procedure is to obtain a relatively complete model that has accurate main-chain atomic positions and residues that are correctly assigned to the sequence. Residues in a morphed model that do not match the electron-density map are removed. Each segment of the resulting trimmed morphed model is then assigned to the sequence of the molecule using information about the connectivity of the chains from the working model and from connections that can be identified from the electron-density map. The procedure was tested by application to a recently determined structure at a resolution of 3.2 Å and was found to increase the number of correctly identified residues in this structure from the 88 obtained using phenix.resolve sequence assignment alone (Terwilliger, 2003 ▶) to 247 of a possible 359. Additionally, the procedure was tested by application to a series of templates with sequence identities to a target structure ranging between 7 and 36%. The mean fraction of correctly identified residues in these cases was increased from 33% using phenix.resolve sequence assignment to 47% using the current procedure. The procedure is simple to apply and is available in the Phenix software package.

  12. Evolutionary ecology of the interactions between aphids and their parasitoids.

    Science.gov (United States)

    Le Ralec, Anne; Anselme, Caroline; Outreman, Yannick; Poirié, Marylène; van Baaren, Joan; Le Lann, Cécile; van Alphen, Jacques J-M

    2010-01-01

    Many organisms, including entomopathogenous fungi, predators or parasites, use aphids as ressources. Parasites of aphids are mostly endoparasitoid insects, i.e. insects which lay eggs inside the body of an other insect which will die as a result of their development. In this article, we review the consequences of the numerous pecularities of aphid biology and ecology for their endoparasitoids, notably the Aphidiinae (Hymenoptera: Braconidae). We first examine the various mechanisms used by aphids for defence against these enemies. We then explore the strategies used by aphidiine parasitoids to exploit their aphid hosts. Finally, we consider the responses of both aphids and parasitoids to ecological constraints induced by seasonal cycles and to environmental variations linked to host plants and climate. The fundamental and applied interest of studying these organisms is discussed. Copyright 2010 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  13. Research on recognition methods of aphid objects in complex backgrounds

    Science.gov (United States)

    Zhao, Hui-Yan; Zhang, Ji-Hong

    2009-07-01

    In order to improve the recognition accuracy among the kinds of aphids in the complex backgrounds, the recognition method among kinds of aphids based on Dual-Tree Complex Wavelet Transform (DT-CWT) and Support Vector Machine (Libsvm) is proposed. Firstly the image is pretreated; secondly the aphid images' texture feature of three crops are extracted by DT-CWT in order to get the training parameters of training model; finally the training model could recognize aphids among the three kinds of crops. By contrasting to Gabor wavelet transform and the traditional extracting texture's methods based on Gray-Level Co-Occurrence Matrix (GLCM), the experiment result shows that the method has a certain practicality and feasibility and provides basic for aphids' recognition between the identification among same kind aphid.

  14. Can Morphing Methods Predict Intermediate Structures?

    Science.gov (United States)

    Weiss, Dahlia R.; Levitt, Michael

    2009-01-01

    Movement is crucial to the biological function of many proteins, yet crystallographic structures of proteins can give us only a static snapshot. The protein dynamics that are important to biological function often happen on a timescale that is unattainable through detailed simulation methods such as molecular dynamics as they often involve crossing high-energy barriers. To address this coarse-grained motion, several methods have been implemented as web servers in which a set of coordinates is usually linearly interpolated from an initial crystallographic structure to a final crystallographic structure. We present a new morphing method that does not extrapolate linearly and can therefore go around high-energy barriers and which can produce different trajectories between the same two starting points. In this work, we evaluate our method and other established coarse-grained methods according to an objective measure: how close a coarse-grained dynamics method comes to a crystallographically determined intermediate structure when calculating a trajectory between the initial and final crystal protein structure. We test this with a set of five proteins with at least three crystallographically determined on-pathway high-resolution intermediate structures from the Protein Data Bank. For simple hinging motions involving a small conformational change, segmentation of the protein into two rigid sections outperforms other more computationally involved methods. However, large-scale conformational change is best addressed using a nonlinear approach and we suggest that there is merit in further developing such methods. PMID:18996395

  15. Aphid-encoded variability in susceptibility to a parasitoid.

    Science.gov (United States)

    Martinez, Adam J; Ritter, Shannon G; Doremus, Matthew R; Russell, Jacob A; Oliver, Kerry M

    2014-06-10

    Many animals exhibit variation in resistance to specific natural enemies. Such variation may be encoded in their genomes or derived from infection with protective symbionts. The pea aphid, Acyrthosiphon pisum, for example, exhibits tremendous variation in susceptibility to a common natural enemy, the parasitic wasp Aphidius ervi. Pea aphids are often infected with the heritable bacterial symbiont, Hamiltonella defensa, which confers partial to complete resistance against this parasitoid depending on bacterial strain and associated bacteriophages. That previous studies found that pea aphids without H. defensa (or other symbionts) were generally susceptible to parasitism, together with observations of a limited encapsulation response, suggested that pea aphids largely rely on infection with H. defensa for protection against parasitoids. However, the limited number of uninfected clones previously examined, and our recent report of two symbiont-free resistant clones, led us to explicitly examine aphid-encoded variability in resistance to parasitoids. After rigorous screening for known and unknown symbionts, and microsatellite genotyping to confirm clonal identity, we conducted parasitism assays using fifteen clonal pea aphid lines. We recovered significant variability in aphid-encoded resistance, with variation levels comparable to that contributed by H. defensa. Because resistance can be costly, we also measured aphid longevity and cumulative fecundity of the most and least resistant aphid lines under permissive conditions, but found no trade-offs between higher resistance and these fitness parameters. These results indicate that pea aphid resistance to A. ervi is more complex than previously appreciated, and that aphids employ multiple tactics to aid in their defense. While we did not detect a tradeoff, these may become apparent under stressful conditions or when resistant and susceptible aphids are in direct competition. Understanding sources and amounts of

  16. Presence of the Aphid, Chaetosiphon fragaefolii, on Strawberry in Argentina

    OpenAIRE

    C?dola, Claudia; Grecob, Nancy

    2010-01-01

    Seasonal abundance of the strawberry aphid complex under different agronomic practices in the outskirts of La Plata, Argentina was studied on strawberry, Fragaria x ananassa Duchesne (Rosales: Rosaceae). Aphid densities were low in strawberry fields in which insecticides and fungicides were used. In addition to Aphis gossypii, Aphis fabae, Mysus persicae and Macrosiphum euphorbiae, the aphid, Chaetosiphon fragaefolii (Cockerell) (Homoptera: Aphididae), was recorded for the first time in this ...

  17. Implications of predator foraging on aphid pathogen dynamics.

    Science.gov (United States)

    Roy, H E; Pell, J K; Clark, S J; Alderson, P G

    1998-05-01

    The foraging behavior of starved and nonstarved second and fourth instar Coccinella septempunctata larvae on dead Acyrthosiphon pisum aphids, either infected with the entomopathogenic fungus Erynia neoaphidis (sporulating) or uninfected, was examined. Larvae searched for longer and fed less when presented with infected rather than uninfected A. pisum. Although no sporulating infected aphids were completely consumed, both adult and larval ladybirds can still be considered as intraguild predators. In a further study, fourth instar larvae fed on dying infected, dead infected (not sporulating), and dead uninfected aphids for similar periods of time but again the infected aphids were seldom entirely consumed. Live uninfected aphids were fed upon for significantly longer than any other prey. Infected aphids which were damaged at an early stage of infection (0, 1, or 2 days after inoculation) did not sporulate, whereas damaged moribund aphids (3 days after inoculation) did subsequently sporulate. Damaged sporulating cadavers continued to sporulate. However, damage to moribund and sporulating infected aphids, both mechanical or due to C. septempunctata feeding, reduced the number of conidia subsequently produced. Larval feeding caused the most significant reduction. Under laboratory conditions, C. septempunctata foraging on infected aphids did, therefore, reduce the pathogen density. However, conidia produced from a damaged cadaver resulted in levels of transmission to healthy aphids comparable to that resulting from an intact cadaver. Furthermore, the presence of a foraging adult ladybird resulted in a significant increase in transmission of the fungus to healthy aphids. Preliminary studies to assess the potential of other aphid natural enemies as intraguild predators illustrated that adults of the generalist carabid, Pterostichus madidus, entirely consumed sporulating cadavers. Third instar lacewing, Chrysoperla carnea, and hoverfly, Episyrphus balteatus, larvae never

  18. Development and Validation of the Morphing Fear Questionnaire (MFQ).

    Science.gov (United States)

    Zysk, Eva; Shafran, Roz; Williams, Tim I; Melli, Gabriele

    2016-11-01

    Morphing fears (also called transformation obsessions) involve concerns that a person may become contaminated by and acquire undesirable characteristics of others. These symptoms are found in patients with obsessive-compulsive disorder (OCD) and are thought to be related to mental contamination. Given the high levels of distress and interference morphing fears can cause, a reliable and valid assessment measure is needed. This article describes the development and evaluation of the Morphing Fear Questionnaire (MFQ), a 13-item measure designed to assess for the presence and severity of morphing fears. A sample of 900 participants took part in the research. Of these, 140 reported having a current diagnosis of OCD (SR-OCD) and 760 reported never having had OCD (N-OCD; of whom 24 reported a diagnosis of an anxiety disorder and 23 reported a diagnosis of depression). Factor structure, reliability and construct and criterion-related validity were investigated. Exploratory and confirmatory factor analyses supported a one-factor structure replicable across the N-OCD and SR-OCD group. The MFQ was found to have high internal consistency and good temporal stability and showed significantly greater associations with convergent measures (assessing obsessive-compulsive symptoms, mental contamination, thought-action fusion and magical thinking) than with divergent measures (assessing depression and anxiety). Moreover, the MFQ successfully discriminated between the SR-OCD sample and the N-OCD group, anxiety disorder sample and depression sample. These findings suggest that the MFQ has sound psychometric properties and that it can be used to assess morphing fear. Clinical implications are discussed. Copyright © 2015 John Wiley & Sons, Ltd. Little remains known about morphing fears, but it is an important area of investigation due to symptoms being highly distressing and often debilitating Because morphing fears commonly present as obscure symptoms, they may not be recognized as a

  19. Conformal-Based Surface Morphing and Multi-Scale Representation

    Directory of Open Access Journals (Sweden)

    Ka Chun Lam

    2014-05-01

    Full Text Available This paper presents two algorithms, based on conformal geometry, for the multi-scale representations of geometric shapes and surface morphing. A multi-scale surface representation aims to describe a 3D shape at different levels of geometric detail, which allows analyzing or editing surfaces at the global or local scales effectively. Surface morphing refers to the process of interpolating between two geometric shapes, which has been widely applied to estimate or analyze deformations in computer graphics, computer vision and medical imaging. In this work, we propose two geometric models for surface morphing and multi-scale representation for 3D surfaces. The basic idea is to represent a 3D surface by its mean curvature function, H, and conformal factor function λ, which uniquely determine the geometry of the surface according to Riemann surface theory. Once we have the (λ, H parameterization of the surface, post-processing of the surface can be done directly on the conformal parameter domain. In particular, the problem of multi-scale representations of shapes can be reduced to the signal filtering on the λ and H parameters. On the other hand, the surface morphing problem can be transformed to an interpolation process of two sets of (λ, H parameters. We test the proposed algorithms on 3D human face data and MRI-derived brain surfaces. Experimental results show that our proposed methods can effectively obtain multi-scale surface representations and give natural surface morphing results.

  20. Heterospecific aggression bias towards a rarer colour morph.

    Science.gov (United States)

    Lehtonen, Topi K; Sowersby, Will; Wong, Bob B M

    2015-09-22

    Colour polymorphisms are a striking example of phenotypic diversity, yet the sources of selection that allow different morphs to persist within populations remain poorly understood. In particular, despite the importance of aggression in mediating social dominance, few studies have considered how heterospecific aggression might contribute to the maintenance or divergence of different colour morphs. To redress this gap, we carried out a field-based study in a Nicaraguan crater lake to investigate patterns of heterospecific aggression directed by the cichlid fish, Hypsophrys nicaraguensis, towards colour polymorphic cichlids in the genus Amphilophus. We found that H. nicaraguensis was the most frequent territorial neighbour of the colour polymorphic A. sagittae. Furthermore, when manipulating territorial intrusions using models, H. nicaraguensis were more aggressive towards the gold than dark colour morph of the sympatric Amphilophus species, including A. sagittae. Such a pattern of heterospecific aggression should be costly to the gold colour morph, potentially accounting for its lower than expected frequency and, more generally, highlighting the importance of considering heterospecific aggression in the context of morph frequencies and coexistence in the wild. © 2015 The Author(s).

  1. Aphid Species Affect Foraging Behavior of Coccinella septempunctata (Coccinellidae: Coleoptera).

    Science.gov (United States)

    Farooq, Muhammad Umar; Qadri, Hafiz Faqir Hussain; Khan, Muhammad Ahmad

    2017-01-01

    Flowers are admirable in scenic good looks and artistic beautification. These are also playing necessary roles in therapeutic preparations. Aphid is an important sucking pest of various flowers in ornamental territories and it is generally controlled by predators, so it was necessary to evaluate which aphid species affect the predator more or less. Biocontrol agent Coccinella septempunctata was used against cosmos aphid (Aphis spiraecola, rose aphid (Macrosiphum rosea), gul e ashrafi aphid (Aphis fabae), kaner aphid (Aphis nerii), chandni aphid (Sitobion avenae), dahlia aphid (Myzus persicae) and annual chrysanthemum aphid (Macrosiphoniella sanborni). The grub of C. septempunctata consumed 283.8±9.04 M. rosea, 487.7±12.6 M. sanborni, 432.75±16.02 A. spiraecola, 478.2±8.07 A. fabae, 552.3±9.04 M. persicae, 142±1.32 A. nerii and 498.5±13.09 S. avenae in its whole larval life. The M. persicae and M. rosea consuming grubs showed 100% adult emergence while, M. sanborni, A. spiraecola, A. fabae and S. avenae showed 96.58, 89.02, 94.78 and 75.45% adult emergence, respectively. The C. septempunctata has significant predatory potential against A. spiraecola, M. rosea, A. fabae, S. avenae, M. persicae and M. sanborni except A. nerii. Thus, further studies are needed to find out alternate predator to control A. nerii on ornamentals.

  2. On the evolution of dispersal and altruism in aphids.

    Science.gov (United States)

    Abbot, Patrick

    2009-10-01

    How competitive interactions and population structure promote or inhibit cooperation in animal groups remains a key challenge in social evolution. In eusocial aphids, there is no single explanation for what predisposes some lineages of aphids to sociality, and not others. Because the assumption has been that most aphid species occur in essentially clonal groups, the roles of intra- and interspecific competition and population structure in aphid sociality have been given little consideration. Here, I used microsatellites to evaluate the patterns of variation in the clonal group structure of both social and nonsocial aphid species. Multiclonal groups are consistent features across sites and host plants, and all species-social or not-can be found in groups composed of large fractions of multiple clones, and even multiple species. Between-group dispersal in gall-forming aphids is ubiquitous, implying that factors acting ultimately to increase between-clone interactions and decrease within-group relatedness were present in aphids prior to the origins of sociality. By demonstrating that between-group dispersal is common in aphids, and thus interactions between clones are also common, these results suggest that understanding the ecological dynamics of dispersal and competition may offer unique insights into the evolutionary puzzle of sociality in aphids.

  3. Watery Saliva Secreted by the Grain Aphid Sitobion avenae Stimulates Aphid Resistance in Wheat.

    Science.gov (United States)

    Zhang, Yong; Fan, Jia; Francis, Frédéric; Chen, Julian

    2017-10-11

    Infestation with Sitobion avenae induces localized defense responses in wheat; in this study, the role of S. avenae watery saliva in resistance induction was examined by infiltrating aphid saliva into wheat leaves. After feeding S. avenae on an artificial diet for 48 h, we first collected watery saliva from them and then separated the salivary proteins using one-dimensional gel electrophoresis. Gene expression studies showed that infiltration of S. avenae watery saliva in wheat leaves induced a strong salicylic acid-responsive defense but moderate jasmonic acid-dependent defense. Feeding on wheat leaves infiltrated with aphid saliva, compared with untreated leaves, significantly decreased the number of nymphs produced per day and the intrinsic rate of increase of the population of S. avenae. In a choice test against untreated wheat, saliva-infiltrated wheat had repellent effects on aphids. Additionally, electrical penetration graph results showed that the feeding behavior of S. avenae on saliva-treated wheat was negatively affected compared with that on untreated wheat. These findings provided direct evidence that salivary components of S. avenae are involved in the induction of wheat resistance against aphids and further demonstrated the important roles of watery saliva in aphid-plant interactions.

  4. Development of Advanced High Lift Leading Edge Technology for Laminar Flow Wings

    Science.gov (United States)

    Bright, Michelle M.; Korntheuer, Andrea; Komadina, Steve; Lin, John C.

    2013-01-01

    This paper describes the Advanced High Lift Leading Edge (AHLLE) task performed by Northrop Grumman Systems Corporation, Aerospace Systems (NGAS) for the NASA Subsonic Fixed Wing project in an effort to develop enabling high-lift technology for laminar flow wings. Based on a known laminar cruise airfoil that incorporated an NGAS-developed integrated slot design, this effort involved using Computational Fluid Dynamics (CFD) analysis and quality function deployment (QFD) analysis on several leading edge concepts, and subsequently down-selected to two blown leading-edge concepts for testing. A 7-foot-span AHLLE airfoil model was designed and fabricated at NGAS and then tested at the NGAS 7 x 10 Low Speed Wind Tunnel in Hawthorne, CA. The model configurations tested included: baseline, deflected trailing edge, blown deflected trailing edge, blown leading edge, morphed leading edge, and blown/morphed leading edge. A successful demonstration of high lift leading edge technology was achieved, and the target goals for improved lift were exceeded by 30% with a maximum section lift coefficient (Cl) of 5.2. Maximum incremental section lift coefficients ( Cl) of 3.5 and 3.1 were achieved for a blown drooped (morphed) leading edge concept and a non-drooped leading edge blowing concept, respectively. The most effective AHLLE design yielded an estimated 94% lift improvement over the conventional high lift Krueger flap configurations while providing laminar flow capability on the cruise configuration.

  5. On the Importance of Morphing Deformation Scheduling for Actuation Force and Energy

    Directory of Open Access Journals (Sweden)

    Roeland De Breuker

    2016-11-01

    Full Text Available Morphing aircraft offer superior properties as compared to non-morphing aircraft. They can achieve this by adapting their shape depending on the requirements of various conflicting flight conditions. These shape changes are often associated with large deformations and strains, and hence dedicated morphing concepts are developed to carry out the required changes in shape. Such intricate mechanisms are often heavy, which reduces, or even completely cancels, the performance increase of the morphing aircraft. Part of this weight penalty is determined by the required actuators and associated batteries, which are mainly driven by the required actuation force and energy. Two underexposed influences on the actuation force and energy are the flight condition at which morphing should take place and the order of the morphing manoeuvres, also called morphing scheduling. This paper aims at highlighting the importance of both influences by using a small Unmanned Aerial Vehicle (UAV with different morphing mechanisms as an example. The results in this paper are generated using a morphing aircraft analysis and design code that was developed at the Delft University of Technology. The importance of the flight condition and a proper morphing schedule is demonstrated by investigating the required actuation forces for various flight conditions and morphing sequences. More importantly, the results show that there is not necessarily one optimal flight condition or morphing schedule and a tradeoff needs to be made.

  6. The morphing of geographical features by Fourier transformation.

    Science.gov (United States)

    Li, Jingzhong; Liu, Pengcheng; Yu, Wenhao; Cheng, Xiaoqiang

    2018-01-01

    This paper presents a morphing model of vector geographical data based on Fourier transformation. This model involves three main steps. They are conversion from vector data to Fourier series, generation of intermediate function by combination of the two Fourier series concerning a large scale and a small scale, and reverse conversion from combination function to vector data. By mirror processing, the model can also be used for morphing of linear features. Experimental results show that this method is sensitive to scale variations and it can be used for vector map features' continuous scale transformation. The efficiency of this model is linearly related to the point number of shape boundary and the interceptive value n of Fourier expansion. The effect of morphing by Fourier transformation is plausible and the efficiency of the algorithm is acceptable.

  7. Morphing of Building Footprints Using a Turning Angle Function

    Directory of Open Access Journals (Sweden)

    Jingzhong Li

    2017-06-01

    Full Text Available We study the problem of morphing two polygons of building footprints at two different scales. This problem frequently occurs during the continuous zooming of interactive maps. The ground plan of a building footprint on a map has orthogonal characteristics, but traditional morphing methods cannot preserve these geographic characteristics at intermediate scales. We attempt to address this issue by presenting a turning angle function-based morphing model (TAFBM that can generate polygons at an intermediate scale with an identical turning angle for each side. Thus, the orthogonal characteristics can be preserved during the entire interpolation. A case study demonstrates that the model yields good results when applied to data from a building map at various scales. During the continuous generalization, the orthogonal characteristics and their relationships with the spatial direction and topology are well preserved.

  8. NASA's Morphing Project Research Summaries in Fiscal Year 2002

    Science.gov (United States)

    McGowan, Anna-Maria R.; Waszak, Martin R.

    2005-01-01

    The Morphing Project at the National Aeronautics and Space Agency s (NASA) Langley Research Center (LaRC) is part of the Breakthrough Vehicle Technologies Project, Vehicle Systems Program that conducts fundamental research on advanced technologies for future flight vehicles. The objectives of the Morphing Project are to develop and assess the advanced technologies and integrated component concepts to enable efficient, multi-point adaptability of flight vehicles; primarily through the application of adaptive structures and adaptive flow control to substantially alter vehicle performance characteristics. This document is a compilation of research summaries and other information on the project for fiscal year 2002. The focus is to provide a brief overview of the project content, technical results and lessons learned. At the time of publication, the Vehicle Systems Program (which includes the Morphing Project) is undergoing a program re-planning and reorganization. Accordingly, the programmatic descriptions of this document pertain only to the program as of fiscal year 2002.

  9. Model morphing and sequence assignment after molecular replacement.

    Science.gov (United States)

    Terwilliger, Thomas C; Read, Randy J; Adams, Paul D; Brunger, Axel T; Afonine, Pavel V; Hung, Li-Wei

    2013-11-01

    A procedure termed `morphing' for improving a model after it has been placed in the crystallographic cell by molecular replacement has recently been developed. Morphing consists of applying a smooth deformation to a model to make it match an electron-density map more closely. Morphing does not change the identities of the residues in the chain, only their coordinates. Consequently, if the true structure differs from the working model by containing different residues, these differences cannot be corrected by morphing. Here, a procedure that helps to address this limitation is described. The goal of the procedure is to obtain a relatively complete model that has accurate main-chain atomic positions and residues that are correctly assigned to the sequence. Residues in a morphed model that do not match the electron-density map are removed. Each segment of the resulting trimmed morphed model is then assigned to the sequence of the molecule using information about the connectivity of the chains from the working model and from connections that can be identified from the electron-density map. The procedure was tested by application to a recently determined structure at a resolution of 3.2 Å and was found to increase the number of correctly identified residues in this structure from the 88 obtained using phenix.resolve sequence assignment alone (Terwilliger, 2003) to 247 of a possible 359. Additionally, the procedure was tested by application to a series of templates with sequence identities to a target structure ranging between 7 and 36%. The mean fraction of correctly identified residues in these cases was increased from 33% using phenix.resolve sequence assignment to 47% using the current procedure. The procedure is simple to apply and is available in the Phenix software package.

  10. Morphing methods to visualize coarse-grained protein dynamics.

    Science.gov (United States)

    Weiss, Dahlia R; Koehl, Patrice

    2014-01-01

    Morphing was initially developed as a cinematic effect, where one image is seamlessly transformed into another image. The technique was widely adopted by biologists to visualize the transition between protein conformational states, generating an interpolated pathway from an initial to a final protein structure. Geometric morphing seeks to create visually suggestive movies that illustrate structural changes between conformations but do not necessarily represent a biologically relevant pathway, while minimum energy path (MEP) interpolations aim at describing the true transition state between the crystal structure minima in the energy landscape.

  11. Optimization of morphing flaps based on fluid structure interaction modeling

    DEFF Research Database (Denmark)

    Barlas, Athanasios; Akay, Busra

    2018-01-01

    This article describes the design optimization of morphing trailing edge flaps for wind turbines with ‘smart blades’. A high fidelity Fluid Structure Interaction (FSI) simulation framework is utilized, comprised of 2D Finite Element Analysis (FEA) and Computational Fluid Dynamics (CFD) models....... A coupled aero-structural simulation of a 10% chordwise length morphing trailing edge flap for a 4 MW wind turbine rotor is carried out and response surfaces are produced with respect to the flap internal geometry design parameters for the design conditions. Surrogate model based optimization is applied...

  12. Morphing-Based Shape Optimization in Computational Fluid Dynamics

    Science.gov (United States)

    Rousseau, Yannick; Men'Shov, Igor; Nakamura, Yoshiaki

    In this paper, a Morphing-based Shape Optimization (MbSO) technique is presented for solving Optimum-Shape Design (OSD) problems in Computational Fluid Dynamics (CFD). The proposed method couples Free-Form Deformation (FFD) and Evolutionary Computation, and, as its name suggests, relies on the morphing of shape and computational domain, rather than direct shape parameterization. Advantages of the FFD approach compared to traditional parameterization are first discussed. Then, examples of shape and grid deformations by FFD are presented. Finally, the MbSO approach is illustrated and applied through an example: the design of an airfoil for a future Mars exploration airplane.

  13. Aeromechanics of an Optimized, Actively-Morphing Rotor System

    Science.gov (United States)

    2013-09-17

    wind   tunnel  tests  as  well  as  a   good  description  of  the   rotor  geometry.  UMARC  has  been  validated...Morphing   rotor  final  report:  N000140911921  (Chopra,  UMD)     Graham  Bowen-­‐Davies  9/4/2013   Final Progress Report...on “Aeromechanics of an Optimized, Actively-Morphing Rotor System” to Office Naval Research Air Vehicle Technology

  14. Inflatable Wing Morphing Aircraft Aeroservoelastic Control and Design Demonstration, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The role of UASs in the DoD has been continuously growing and is expected to show much higher growth rates in operations in the near future. A pressing need for such...

  15. Structural Optimization of a Distributed Actuation System in a Flexible In-Plane Morphing Wing

    Science.gov (United States)

    2007-06-01

    DMAP Code These are the DMAP statements to inlude in the NASTRAN TM input file so that the stiffness matrix is an output of the analysis. A.1 DMAP ...67 Appendix A. DMAP Code . . . . . . . . . . . . . . . . . . . . . . . . 69 A.1 DMAP Stiffness Output...25 DMAP Direct Matrix Abstraction Program . . . . . . . . . . . . . 43 xv Structural Optimization of a Distributed Actuation System in a

  16. Endocrine differences among colour morphs in a lizard with alternative behavioural strategies.

    Science.gov (United States)

    Yewers, Madeleine St Clair; Jessop, Tim S; Stuart-Fox, Devi

    2017-07-01

    Alternative behavioural strategies of colour morphs are expected to associate with endocrine differences and to correspond to differences in physical performance (e.g. movement speed, bite force in lizards); yet the nature of correlated physiological and performance traits in colour polymorphic species varies widely. Colour morphs of male tawny dragon lizards Ctenophorus decresii have previously been found to differ in aggressive and anti-predator behaviours. We tested whether known behavioural differences correspond to differences in circulating baseline and post-capture stress levels of androgen and corticosterone, as well as bite force (an indicator of aggressive performance) and field body temperature. Immediately after capture, the aggressive orange morph had higher circulating androgen than the grey morph or the yellow morph. Furthermore, the orange morph maintained high androgen following acute stress (30min of capture); whereas androgen increased in the grey and yellow morphs. This may reflect the previously defined behavioural differences among morphs as the aggressive response of the yellow morph is conditional on the colour of the competitor and the grey morph shows consistently low aggression. In contrast, all morphs showed an increase in corticosterone concentration after capture stress and morphs did not differ in levels of corticosterone stress magnitude (CSM). Morphs did not differ in size- and temperature-corrected bite force but did in body temperature at capture. Differences in circulating androgen and body temperature are consistent with morph-specific behavioural strategies in C. decresii but our results indicate a complex relationship between hormones, behaviour, temperature and bite force within and between colour morphs. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Potato aphid Macrosiphum euphorbiae performance is determined by aphid genotype and not mycorrhizal fungi or water availability.

    Science.gov (United States)

    Karley, Alison Jane; Emslie-Smith, Matthew; Bennett, Alison Elizabeth

    2017-12-01

    Intra- and interspecific variation in plant and insect traits can alter the strength and direction of insect-plant interactions, with outcomes modified by soil biotic and abiotic conditions. We used the potato aphid (Macrosiphum euphorbiae Thomas) feeding on cultivated Solanum tuberosum and wild Solanum berthaulti to study the impact of water availability and plant mutualistic arbuscular mycorrhizal (AM) fungi on aphid performance and susceptibility to a parasitoid wasp (Aphidius ervi Haliday). Plants were grown under glass with live or sterile AM fungal spores and supplied with sufficient or reduced water supply. Plants were infested with 1 of 3 genotypes of M. euphorbiae or maintained as aphid-free controls; aphid abundance was scored after 1 week, after which aphid susceptibility to A. ervi was assayed ex planta. Solanum tuberosum accumulated c. 20% more dry mass than S. berthaultii, and root mass of S. berthaultii was smallest under reduced water supply in the presence of AM fungi. Aphid abundance was lowest on S. berthaultii and highest for genotype "2" aphids; genotype "1" aphid density was particularly reduced on S. berthaultii. Aphid genotype "1" exhibited low susceptibility to parasitism and was attacked less frequently than the other two more susceptible aphid genotypes. Neither AM fungi nor water availability affected insect performance. Our study suggests a fitness trade-off in M. euphorbiae between parasitism resistance and aphid performance on poor quality Solanum hosts that warrants further exploration, and indicates the importance of accounting for genotype identity in determining the outcome of multitrophic interactions. © 2017 Institute of Zoology, Chinese Academy of Sciences.

  18. Effect of Intercropping Collard with Beans or Onions on Aphid ...

    African Journals Online (AJOL)

    ... resistance and pollution to the environment. This study was therefore, an attempt to look into alternative and environmentally friendly ways of controlling aphids in collard. To achieve this, two studies were conducted in Kenya to determine the effects of intercropping and nitrogen fertilization on aphid population on collard ...

  19. New aphid (Aphidoidea) records for the Netherlands (1984-2005)

    NARCIS (Netherlands)

    Piron, P.G.M.

    2009-01-01

    Presented are 18 species.of aphids in combination with their food-plants found in The Netherlands from 1984 to 2005 not earlier described here. Among these are well-known species that are caught with the high suction trap andlor MOERICKE yellow water traps and aphids new for The Netherlands. The

  20. Molecular sabotage of plant defense by aphid saliva

    NARCIS (Netherlands)

    Will, T.; Tjallingii, W.F.; Thönnessen, A.; Bel, van A.J.E.

    2007-01-01

    Aphids, which constitute one of the most important groups of agricultural pests, ingest nutrients from sieve tubes, the photoassimilate transport conduits in plants. Aphids are able to successfully puncture sieve tubes with their piercing mouthparts (stylets) and ingest phloem sap without eliciting

  1. Detection of novel QTLs for foxglove aphid resistance in soybean

    Science.gov (United States)

    Foxglove aphid, Aulacorthum solani (Kaltenbach), is a Hemipteran insect that infected a wide variety of plants worldwide and caused serious yield losses in crops. The objective of this study was to identify the putative QTL for foxglove aphid resistance in wild soybean, PI 366121, (Glycine soja Sieb...

  2. Evaluation on the resistance to aphids of wheat germplasm ...

    African Journals Online (AJOL)

    A collection of more than 200 wheat lines from the main wheat-producing areas of China was evaluated for resistance to wheat aphids, using fuzzy recognition technique in five field experiments over 2 years. The results show that susceptibility to wheat aphids was exhibited in most of the lines tested, and no immune and ...

  3. Saliva fractions from South African Russian wheat aphid biotypes ...

    African Journals Online (AJOL)

    The Russian wheat aphid (RWA), Diuraphis noxia (Kurdjomov, 1913), is a notorious pest that reduces yield in wheat. Nevertheless, the source of eliciting activity during RWA–wheat interaction has not been established. This paper reports on the isolation of eliciting activity in aphid saliva that is capable of inducing ...

  4. The resistance of lettuce to the aphid Nasonovia ribisnigri

    NARCIS (Netherlands)

    Helden, van M.

    1995-01-01

    The resistance of lettuce to the aphid Nasonovia ribisnigri is based on a single, dominant gene, the Nr-gene. On the resistant plant aphids died within a few days, without any honeydew production. Transfer-experiments with a short stay on a resistant plant followed by a

  5. Molecular basis and ecological relevance of aphid body colors.

    Science.gov (United States)

    Tsuchida, Tsutomu

    2016-10-01

    Aphids are small phloem sap-feeding insects, and show color polymorphism even within the same species. Crossing experiments have revealed the inheritance pattern of the body color. Coloration of aphids is determined by mainly three pigments, melanin, carotenoid, and aphin, and is influenced by both abiotic and biotic environmental factors. Aphid body colors also seem to correspond with specific biological functions under various environments. Partly due to the presence of natural enemies in the environment, a variety of physiological and behavioral responses have evolved in each color form. Thus, predation is one of the most significant external factors for maintaining body color polymorphisms. In addition, endosymbiont infections also influence aphid body color and prey-predator interactions. However, many unsolved questions remain regarding the molecular basis for and biological functions of aphid body colors. Further work, including the development of molecular techniques for comprehensive functional analysis, is needed in these areas. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Ants farm subterranean aphids mostly in single clone groups

    DEFF Research Database (Denmark)

    Ivens, Aniek B.F.; Kronauer, Daniel Jan Christoph; Pen, Ido

    2012-01-01

    a single aphid species, a significantly higher percentage than expected from a random distribution. Over 60% of these single-species mounds had a single aphid clone, and clones tended to persist across subsequent years. Whenever multiple species/clones co-occurred in the same mound, they were spatially...... separated with more than 95% of the aphid chambers containing individuals of a single clone. Conclusions L. flavus “husbandry” is characterized by low aphid “livestock” diversity per colony, especially at the nest-chamber level, but it lacks the exclusive monocultures known from other cultivation mutualisms...... benefitting the domesticated aphids as long as their clone-mates reproduce successfully. The cost-benefit logic of this type of polyculture husbandry has striking analogies with human farming practices based on slaughtering young animals for meat to maximize milk-production by a carefully regulated adult...

  7. A morphing trailing edge flap system for wind turbine blades

    DEFF Research Database (Denmark)

    Aagaard Madsen, Helge; Barlas, Athanasios; Løgstrup Andersen, Tom

    2015-01-01

    The development of a morphing trailing edge system for wind turbines, also called a flap system, is presented. The functionality is simple as the flap deflection is controlled by pressurized air or a fluid in a number of voids in the flap made of an elastic material. It is thus a robust system...

  8. Morphing ab initio potential energy curve of beryllium monohydride

    Czech Academy of Sciences Publication Activity Database

    Špirko, Vladimír

    2016-01-01

    Roč. 330, Dec (2016), s. 89-95 ISSN 0022-2852 Institutional support: RVO:61388963 Keywords : beryllium monohydride * potential energy function * reduced potential * homotopic morphing Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.618, year: 2016

  9. A bistable mechanism for chord extension morphing rotors

    Science.gov (United States)

    Johnson, Terrence; Frecker, Mary; Gandhi, Farhan

    2009-03-01

    Research efforts have shown that helicopter rotor blade morphing is an effective means to improve flight performance. Previous example of rotor blade morphing include using smart-materials for trailing deflection and rotor blade twist and tip twist, the development of a comfortable airfoil using compliant mechanisms, the use of a Gurney flap for air-flow deflection and centrifugal force actuated device to increase the span of the blade. In this paper we explore the use of a bistable mechanism for rotor morphing, specifically, blade chord extension using a bistable arc. Increasing the chord of the rotor blade is expected to generate more lift-load and improve helicopter performance. Bistable or "snap through" mechanisms have multiple stable equilibrium states and are a novel way to achieve large actuation output stroke. Bistable mechanisms do not require energy input to maintain a stable equilibrium state as both states do not require locking. In this work, we introduce a methodology for the design of bistable arcs for chord morphing using the finite element analysis and pseudo-rigid body model, to study the effect of different arc types, applied loads and rigidity on arc performance.

  10. Design optimization and uncertainty analysis of SMA morphing structures

    International Nuclear Information System (INIS)

    Oehler, S D; Hartl, D J; Lopez, R; Malak, R J; Lagoudas, D C

    2012-01-01

    The continuing implementation of shape memory alloys (SMAs) as lightweight solid-state actuators in morphing structures has now motivated research into finding optimized designs for use in aerospace control systems. This work proposes methods that use iterative analysis techniques to determine optimized designs for morphing aerostructures and consider the impact of uncertainty in model variables on the solution. A combination of commercially available and custom coded tools is utilized. ModelCenter, a suite of optimization algorithms and simulation process management tools, is coupled with the Abaqus finite element analysis suite and a custom SMA constitutive model to assess morphing structure designs in an automated fashion. The chosen case study involves determining the optimized configuration of a morphing aerostructure assembly that includes SMA flexures. This is accomplished by altering design inputs representing the placement of active components to minimize a specified cost function. An uncertainty analysis is also conducted using design of experiment methods to determine the sensitivity of the solution to a set of uncertainty variables. This second study demonstrates the effective use of Monte Carlo techniques to simulate the variance of model variables representing the inherent uncertainty in component fabrication processes. This paper outlines the modeling tools used to execute each case study, details the procedures for constructing the optimization problem and uncertainty analysis, and highlights the results from both studies. (paper)

  11. Parasitic wasp responses to symbiont-based defense in aphids

    Directory of Open Access Journals (Sweden)

    Oliver Kerry M

    2012-02-01

    Full Text Available Abstract Background Recent findings indicate that several insect lineages receive protection against particular natural enemies through infection with heritable symbionts, but little is yet known about whether enemies are able to discriminate and respond to symbiont-based defense. The pea aphid, Acyrthosiphon pisum, receives protection against the parasitic wasp, Aphidius ervi, when infected with the bacterial symbiont Hamiltonella defensa and its associated bacteriophage APSE (Acyrthosiphon pisum secondary endosymbiont. Internally developing parasitoid wasps, such as A. ervi, use maternal and embryonic factors to create an environment suitable for developing wasps. If more than one parasitoid egg is deposited into a single aphid host (superparasitism, then additional complements of these factors may contribute to the successful development of the single parasitoid that emerges. Results We performed experiments to determine if superparasitism is a tactic allowing wasps to overcome symbiont-mediated defense. We found that the deposition of two eggs into symbiont-protected aphids significantly increased rates of successful parasitism relative to singly parasitized aphids. We then conducted behavioral assays to determine whether A. ervi selectively superparasitizes H. defensa-infected aphids. In choice tests, we found that A. ervi tends to deposit a single egg in uninfected aphids, but two or more eggs in H. defensa-infected aphids, indicating that oviposition choices may be largely determined by infection status. Finally, we identified differences in the quantity of the trans-β-farnesene, the major component of aphid alarm pheromone, between H. defensa-infected and uninfected aphids, which may form the basis for discrimination. Conclusions Here we show that the parasitic wasp A. ervi discriminates among symbiont-infected and uninfected aphids, and changes its oviposition behavior in a way that increases the likelihood of overcoming symbiont

  12. A new non-linear vortex lattice method: Applications to wing aerodynamic optimizations

    Directory of Open Access Journals (Sweden)

    Oliviu Şugar Gabor

    2016-10-01

    Full Text Available This paper presents a new non-linear formulation of the classical Vortex Lattice Method (VLM approach for calculating the aerodynamic properties of lifting surfaces. The method accounts for the effects of viscosity, and due to its low computational cost, it represents a very good tool to perform rapid and accurate wing design and optimization procedures. The mathematical model is constructed by using two-dimensional viscous analyses of the wing span-wise sections, according to strip theory, and then coupling the strip viscous forces with the forces generated by the vortex rings distributed on the wing camber surface, calculated with a fully three-dimensional vortex lifting law. The numerical results obtained with the proposed method are validated with experimental data and show good agreement in predicting both the lift and pitching moment, as well as in predicting the wing drag. The method is applied to modifying the wing of an Unmanned Aerial System to increase its aerodynamic efficiency and to calculate the drag reductions obtained by an upper surface morphing technique for an adaptable regional aircraft wing.

  13. Material characterization for morphing purposes in order to match flight requirements

    Science.gov (United States)

    Geier, Sebastian; Kintscher, Markus; Heintze, Olaf; Wierach, Peter; Monner, Hans-Peter; Wiedemann, Martin

    2012-04-01

    Natural laminar flow is one of the challenging aims of the current aerospace research. Main reasons for the aerodynamic transition from laminar into turbulent flow focusing on the airfoil-structure is the aerodynamic shape and the surface roughness. The Institute of Composite Structures and Adaptive Systems at the German Aerospace Center in Braunschweig works on the optimization of the aerodynamic-loaded structure of future aircrafts in order to increase their efficiency. Providing wing structures suited for natural laminar flow is a step towards this goal. Regarding natural laminar flow, the structural design of the leading edge of a wing is of special interest. An approach for a gap-less leading edge was developed to provide a gap- and step-less high quality surface suited for natural laminar flow and to reduce slat noise. In a national project the first generation of the 3D full scale demonstrator was successfully tested in 2010. The prototype consists of several new technologies, opening up the issue of matching the long and challenging list of airworthiness requirements simultaneously. Therefore the developed composite structure was intensively tested for further modifications according to meet requirements for abrasion, impact and deicing basically. The former presented structure consists completely of glass-fiber-prepreg (GFRP-prepreg). New functions required the addition of a new material-mix, which has to fit into the manufacturing-chain of the composite structure. In addition the hybrid composites have to withstand high loadings, high bending-induced strains (1%) and environmentally influenced aging. Moreover hot-wet cycling tests are carried out for the basic GFRP-structure in order to simulate the long term behavior of the material under extrem conditions. The presented paper shows results of four-points-bending-tests of the most critical section of the morphing leading edge device. Different composite-hybrids are built up and processed. An experimental

  14. On the Importance of Nonlinear Aeroelasticity and Energy Efficiency in Design of Flying Wing Aircraft

    Directory of Open Access Journals (Sweden)

    Pezhman Mardanpour

    2015-01-01

    Full Text Available Energy efficiency plays important role in aeroelastic design of flying wing aircraft and may be attained by use of lightweight structures as well as solar energy. NATASHA (Nonlinear Aeroelastic Trim And Stability of HALE Aircraft is a newly developed computer program which uses a nonlinear composite beam theory that eliminates the difficulties in aeroelastic simulations of flexible high-aspect-ratio wings which undergoes large deformation, as well as the singularities due to finite rotations. NATASHA has shown that proper engine placement could significantly increase the aeroelastic flight envelope which typically leads to more flexible and lighter aircraft. The areas of minimum kinetic energy for the lower frequency modes are in accordance with the zones with maximum flutter speed and have the potential to save computational effort. Another aspect of energy efficiency for High Altitude, Long Endurance (HALE drones stems from needing to minimize energy consumption because of limitations on the source of energy, that is, solar power. NATASHA is capable of simulating the aeroelastic passive morphing maneuver (i.e., morphing without relying on actuators and at as near zero energy cost as possible of the aircraft so as the solar panels installed on the wing are in maximum exposure to sun during different time of the day.

  15. Faba bean forisomes can function in defence against generalist aphids.

    Science.gov (United States)

    Medina-Ortega, Karla J; Walker, Gregory P

    2015-06-01

    Phloem sieve elements have shut-off mechanisms that prevent loss of nutrient-rich phloem sap when the phloem is damaged. Some phloem proteins such as the proteins that form forisomes in legume sieve elements are one such mechanism and in response to damage, they instantly form occlusions that stop the flow of sap. It has long been hypothesized that one function of phloem proteins is defence against phloem sap-feeding insects such as aphids. This study provides the first experimental evidence that aphid feeding can induce phloem protein occlusion and that the aphid-induced occlusions inhibit phloem sap ingestion. The great majority of phloem penetrations in Vicia faba by the generalist aphids Myzus persicae and Macrosiphum euphorbiae triggered forisome occlusion and the aphids eventually withdrew their stylets without ingesting phloem sap. This contrasts starkly with a previous study on the legume-specialist aphid, Acyrthosiphon pisum, where penetration of faba bean sieve elements did not trigger forisome occlusion and the aphids readily ingested phloem sap. Next, forisome occlusion was demonstrated to be the cause of failed phloem ingestion attempts by M. persicae: when occlusion was inhibited by the calcium channel blocker lanthanum, M. persicae readily ingested faba bean phloem sap. © 2014 John Wiley & Sons Ltd.

  16. Aphid Identification and Counting Based on Smartphone and Machine Vision

    Directory of Open Access Journals (Sweden)

    Suo Xuesong

    2017-01-01

    Full Text Available Exact enumeration of aphids before the aphids outbreak can provide basis for precision spray. This paper designs counting software that can be run on smartphones for real-time enumeration of aphids. As a first step of the method used in this paper, images of the yellow sticky board that is aiming to catch insects are segmented from complex background by using GrabCut method; then the images will be normalized by perspective transformation method. The second step is the pretreatment on the images; images of aphids will be segmented by using OSTU threshold method after the effect of random illumination is eliminated by single image difference method. The last step of the method is aphids’ recognition and counting according to area feature of aphids after extracting contours of aphids by contour detection method. At last, the result of the experiment proves that the effect of random illumination can be effectively eliminated by using single image difference method. The counting accuracy in greenhouse is above 95%, while it can reach 92.5% outside. Thus, it can be seen that the counting software designed in this paper can realize exact enumeration of aphids under complicated illumination which can be used widely. The design method proposed in this paper can provide basis for precision spray according to its effective detection insects.

  17. Native aphids of New Zealand--diversity and host associations.

    Science.gov (United States)

    Teulon, D A J; Stufkens, M A W; Drayton, G M; Maw, H E L; Scott, I A W; Bulman, S R; Carver, M; Von Dohlen, C D; Eastop, V F; Foottit, R G

    2013-01-01

    At least 15 species of aphids are now recognised as New Zealand natives and most of these are very likely to be endemic. Most native aphids belong in the subfamily Aphidinae (Aphidini), with a possible single species in Aphidinae-Macrosiphini, at least two in Neophyllaphidinae and one in Taiwanaphidinae. With one exception, native aphids are restricted to a single host plant genus, and these hosts are from 13 genera and 12 plant families in the Pinales and Angiospermae-Eudicotyledonae, suggesting that the aphids are a remnant fauna. No known native aphids have host plants from the Pteridophyta or Angiospermae-Monocotyledonae, with the possible exception of two possibly native species extracted from native tussock grassland turfs. Most host plant genera have some degree of Gondwanan distribution, but only two indigenous species are found on large forest trees and only one host is deciduous. Native aphids have been recorded from sea level to the subalpine zone, reflecting their host plant distributions. Sexual reproduction, followed by several parthenogenetic generations on the same host plant, appears to be the norm for most species. Eggs appear to be used for surviving winter conditions in some species and summer conditions in others. Native aphid distribution and abundance varies with five species considered to be scarce, one species localised, two species sparse and three relatively common based on current knowledge.

  18. Role of the aphid species and their feeding locations in parasitization behavior of Aphelinus abdominalis, a parasitoid of the lettuce aphid Nasonovia ribisnigri

    OpenAIRE

    Shrestha, Govinda; Skovg?rd, Henrik; Reddy, Gadi V. P.; Steenberg, Tove; Enkegaard, Annie

    2017-01-01

    Aphid species feeding on lettuce occupy distinct feeding sites: the lettuce aphid Nasonovia ribisnigri prefers to feed on heart leaves, whereas the potato aphid Macrosiphum euphorbiae feeds only on outer leaves. The aphid parasitoid Aphelinus abdominalis, known to be able to regulate M. euphorbiae on many crops, has recently been indicated as a promising biocontrol candidate also for use against N. ribisnigri, a major pest of lettuce. This study therefore examined A. abdominalis parasitizatio...

  19. Social aggregation in pea aphids: experiment and random walk modeling.

    Science.gov (United States)

    Nilsen, Christa; Paige, John; Warner, Olivia; Mayhew, Benjamin; Sutley, Ryan; Lam, Matthew; Bernoff, Andrew J; Topaz, Chad M

    2013-01-01

    From bird flocks to fish schools and ungulate herds to insect swarms, social biological aggregations are found across the natural world. An ongoing challenge in the mathematical modeling of aggregations is to strengthen the connection between models and biological data by quantifying the rules that individuals follow. We model aggregation of the pea aphid, Acyrthosiphon pisum. Specifically, we conduct experiments to track the motion of aphids walking in a featureless circular arena in order to deduce individual-level rules. We observe that each aphid transitions stochastically between a moving and a stationary state. Moving aphids follow a correlated random walk. The probabilities of motion state transitions, as well as the random walk parameters, depend strongly on distance to an aphid's nearest neighbor. For large nearest neighbor distances, when an aphid is essentially isolated, its motion is ballistic with aphids moving faster, turning less, and being less likely to stop. In contrast, for short nearest neighbor distances, aphids move more slowly, turn more, and are more likely to become stationary; this behavior constitutes an aggregation mechanism. From the experimental data, we estimate the state transition probabilities and correlated random walk parameters as a function of nearest neighbor distance. With the individual-level model established, we assess whether it reproduces the macroscopic patterns of movement at the group level. To do so, we consider three distributions, namely distance to nearest neighbor, angle to nearest neighbor, and percentage of population moving at any given time. For each of these three distributions, we compare our experimental data to the output of numerical simulations of our nearest neighbor model, and of a control model in which aphids do not interact socially. Our stochastic, social nearest neighbor model reproduces salient features of the experimental data that are not captured by the control.

  20. Bacterial Communities of Two Parthenogenetic Aphid Species Cocolonizing Two Host Plants across the Hawaiian Islands ▿

    Science.gov (United States)

    Jones, Ryan T.; Bressan, Alberto; Greenwell, April M.; Fierer, Noah

    2011-01-01

    Aphids (Hemiptera: Aphididae) have been the focus of several studies with respect to their interactions with inherited symbionts, but bacterial communities of most aphid species are still poorly characterized. In this research, we used bar-coded pyrosequencing to characterize bacterial communities in aphids. Specifically, we examined the diversity of bacteria in two obligately parthenogenetic aphid species (the melon aphid, Aphis gossypii, and the cardamom aphid, Pentalonia caladii) cocolonizing two plant species (taro, Colocasia esculenta, and ginger, Alpinia purpurata) across four Hawaiian Islands (Hawaii, Kauai, Maui, and Oahu). Results from this study revealed that heritable symbionts dominated the bacterial communities for both aphid species. The bacterial communities differed significantly between the two species, and A. gossypii harbored a more diverse bacterial community than P. caladii. The bacterial communities also differed across aphid populations sampled from the different islands; however, communities did not differ between aphids collected from the two host plants. PMID:21965398

  1. Bacterial communities of two parthenogenetic aphid species cocolonizing two host plants across the Hawaiian Islands.

    Science.gov (United States)

    Jones, Ryan T; Bressan, Alberto; Greenwell, April M; Fierer, Noah

    2011-12-01

    Aphids (Hemiptera: Aphididae) have been the focus of several studies with respect to their interactions with inherited symbionts, but bacterial communities of most aphid species are still poorly characterized. In this research, we used bar-coded pyrosequencing to characterize bacterial communities in aphids. Specifically, we examined the diversity of bacteria in two obligately parthenogenetic aphid species (the melon aphid, Aphis gossypii, and the cardamom aphid, Pentalonia caladii) cocolonizing two plant species (taro, Colocasia esculenta, and ginger, Alpinia purpurata) across four Hawaiian Islands (Hawaii, Kauai, Maui, and Oahu). Results from this study revealed that heritable symbionts dominated the bacterial communities for both aphid species. The bacterial communities differed significantly between the two species, and A. gossypii harbored a more diverse bacterial community than P. caladii. The bacterial communities also differed across aphid populations sampled from the different islands; however, communities did not differ between aphids collected from the two host plants.

  2. Establishment of in vitro soybean aphids, Aphis glycines (Hemiptera: Aphididae): a tool to facilitate studies of aphid symbionts, plant-insect interactions and insecticide efficacy.

    Science.gov (United States)

    Gunadi, Andika; Bansal, Raman; Finer, John J; Michel, Andy

    2017-06-01

    Studies on plant-insect interactions of the soybean aphid, Aphis glycines (Matsumura), can be influenced by environmental fluctuations, status of the host plant and variability in microbial populations. Maintenance of aphids on in vitro-grown plants minimizes environmental fluctuations, provides uniform host materials and permits the selective elimination of aphid-associated microbes for more standardized controls in aphid research. Aphids were reared on sterile, in vitro-grown soybean seedlings germinated on plant tissue culture media amended with a mixture of antimicrobials. For initiation and maintenance of in vitro aphid colonies, single aphids were inoculated onto single in vitro seedlings. After three rounds of transfer of 'clean' aphids to fresh in vitro seedlings, contamination was no longer observed, and aphids performed equally well when compared with those reared on detached leaves. The addition of the insecticides thiamethoxam and chlorantraniliprole to the culture medium confirmed uptake and caused significant mortality to the in vitro aphids. The use of the antimicrobial mixture removed the associated bacteria Arsenophonus but retained Buchnera and Wolbachia within the in vitro aphids. The in vitro aphid system is a novel and highly useful tool to understand insecticidal efficacy and expand our knowledge of tritrophic interactions among plants, insects and symbionts. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  3. Life history differences between fat and lean morphs of lake charr (Salvelinus namaycush) in Great Slave Lake, Northwest Territories, Canada

    Science.gov (United States)

    Hansen, Michael J.; Nate, Nancy A.; Chavarie, Louise; Muir, Andrew M.; Zimmerman, Mara S.; Krueger, Charles C.

    2016-01-01

    Life history characteristics (size, age, plumpness, buoyancy, survival, growth, and maturity) were compared between fat and lean morphs of lake charr Salvelinus namaycush in Great Slave Lake, Canada, to determine if differences may reflect effects of resource polymorphism. Lake charr were sampled using graded-mesh gill nets set in three depth strata. Of 236 lake charr captured, 122 were a fat morph and 114 were a lean morph. Males and females did not differ from each other in any attributes for either fat or lean morphs. The fat morph averaged 15 mm longer, 481 g heavier, and 4.7 years older than the lean morph. The fat morph averaged 26% heavier and 48% more buoyant at length than the lean morph. Survival of the fat morph was 1.7% higher than that of the lean morph. The fat morph grew at a slower annual rate to a shorter asymptotic length than the lean morph. Fat and lean morphs matured at similar lengths and ages. We concluded that the connection between resource polymorphism and life histories in lean versus fat lake charr suggests that morph-specific restoration objectives may be needed in lakes where lake charr diversity is considered to be a restoration goal.

  4. Escherichia coli K-12 pathogenicity in the pea aphid, Acyrthosiphon pisum, reveals reduced antibacterial defense in aphids.

    Science.gov (United States)

    Altincicek, Boran; Ter Braak, Bas; Laughton, Alice M; Udekwu, Klas I; Gerardo, Nicole M

    2011-10-01

    To better understand the molecular basis underlying aphid immune tolerance to beneficial bacteria and immune defense to pathogenic bacteria, we characterized how the pea aphid Acyrthosiphon pisum responds to Escherichia coli K-12 infections. E. coli bacteria, usually cleared in the hemolymph of other insect species, were capable of growing exponentially and killing aphids within a few days. Red fluorescence protein expressing E. coli K-12 laboratory strain multiplied in the aphid hemolymph as well as in the digestive tract, resulting in death of infected aphids. Selected gene deletion mutants of the E. coli K-12 predicted to have reduced virulence during systemic infections showed no difference in either replication or killing rate when compared to the wild type E. coli strain. Of note, however, the XL1-Blue E. coli K-12 strain exhibited a significant lag phase before multiplying and killing aphids. This bacterial strain has recently been shown to be more sensitive to oxidative stress than other E. coli K-12 strains, revealing a potential role for reactive oxygen species-mediated defenses in the otherwise reduced aphid immune system. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Impact of Rag1 aphid resistant soybeans on Binodoxys communis (Hymenoptera: Braconidae), a parasitoid of soybean aphid (Hemiptera: Aphididae).

    Science.gov (United States)

    Ghising, Kiran; Harmon, Jason P; Beauzay, Patrick B; Prischmann-Voldseth, Deirdre A; Helms, Ted C; Ode, Paul J; Knodel, Janet J

    2012-04-01

    Multiple strategies are being developed for pest management of the soybean aphid, Aphis glycines Matsumura; however, there has been little published research thus far to determine how such strategies may influence each other, thereby complicating their potential effectiveness. A susceptible soybean (Glycine max L.) variety without the Rag1 gene and a near isogenic resistant soybean variety with the Rag1 gene were evaluated in the laboratory for their effects on the fitness of the soybean aphid parasitoid, Binodoxys communis (Gahan). The presence or absence of the Rag1 gene was verified by quantifying soybean aphid growth. To test for fitness effects, parasitoids were allowed to attack soybean aphids on either a susceptible or resistant plant for 24 h and then aphids were kept on the same plant throughout parasitoid development. Parasitoid fitness was measured by mummy and adult parasitoid production, adult parasitoid emergence, development time, and adult size. Parasitoids that attacked soybean aphids on susceptible plants produced more mummies, more adult parasitoids, and had a higher emergence rate compared with those on resistant plants. Adult parasitoids that emerged from resistant plants took 1 d longer and were smaller compared with those from susceptible plants. This study suggests that biological control by B. communis may be compromised when host plant resistance is widely used for pest management of soybean aphids.

  6. The Green Lacewing, Chrysoperla carnea: Preference between Lettuce Aphids, Nasonovia ribisnigri, and Western Flower Thrips, Frankliniella occidentalis

    OpenAIRE

    Shrestha, Govinda; Enkegaard, Annie

    2013-01-01

    This study investigated the prey preference of 3rd instar green lacewing, Chrysoperla carnea Stephens (Neuroptera: Chrysopidae), between western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), and lettuce aphids, Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae) in laboratory experiments at 25 ? 1? C and 70 ? 5% RH with five prey ratios (10 aphids:80 thrips, 25 aphids:65 thrips, 45 aphids:45 thrips, 65 aphids:25 thrips, and 80 aphids:10 thrips). Third instar...

  7. A comparative morphological revision of the aphid genus Myzaphis van der Goot, 1913 (Insecta: Hemiptera: Aphididae) revealed a new genus and three new species.

    Science.gov (United States)

    Kanturski, Mariusz; Barjadze, Shalva; Jensen, Andrew S; Wieczorek, Karina

    2018-01-01

    The aphid genus Myzaphis van der Goot, 1913 from the tribe Macrosiphini is revised to include eight species. Apterous and alate viviparous females, known fundatrices and known sexual morphs (oviparous females and males) of Myzaphis bucktoni, M. juchnevitschae, M. rosarum, M. tianshanica and M. turanica are re-described and illustrated. Lectotype and paralectotypes of Myzaphis bucktoni and M. turanica are designated. The status of M. komatsubarae nomen dubium is discussed. Myzaphis avariolosa is regarded as a species belonging to the genus Ericaphis. Three new species: M. oezdemirae Kanturski & Barjadze sp. nov., M. tuatayae Kanturski & Barjadze sp. nov. from Turkey and M. rezwanii Kanturski & Barjadze sp. nov. from Iran are described and illustrated. Myzaphis bucktoni is recorded from Portugal for the first time. Diagnosis of the genus Myzaphis van der Goot, 1913 is redefined and a new genus Richardsaphis Kanturski & Barjadze gen. nov. is erected with the type species R. canadensis (Richards) comb. nov. Richardsaphis is for the first time recorded from the USA and hitherto unknown oviparous female and alate male are described and illustrated. Original keys to species of the genus Myzaphis and aphid genera of the tribe Macrosiphini with 2-2-2 first tarsal chaetotaxy are also provided.

  8. UV-B impact on aphid performance mediated by plant quality and plant changes induced by aphids.

    Science.gov (United States)

    Kuhlmann, F; Müller, C

    2010-07-01

    Plants face various abiotic and biotic environmental factors and therefore need to adjust their phenotypic traits on several levels. UV-B radiation is believed to impact herbivorous insects via host plant changes. Plant responses to abiotic challenges (UV-B radiation) and their interaction with two aphid species were explored in a multifactor approach. Broccoli plants [Brassica oleracea L. convar. botrytis (L.), Brassicaceae] were grown in two differently covered greenhouses, transmitting either 80% (high UV-B) or 4% (low UV-B) of ambient UV-B. Three-week-old plants were infested with either specialist cabbage aphids [Brevicoryne brassicae (L.), Sternorrhyncha, Aphididae] or generalist green peach aphids [Myzus persicae (Sulzer), Sternorrhyncha, Aphididae]. Plants grown under high-UV-B intensities were smaller and had higher flavonoid concentrations. Furthermore, these plants had reduced cuticular wax coverage, whereas amino acid concentrations of the phloem sap were little influenced by different UV-B intensities. Cabbage aphids reproduced less on plants grown under high UV-B than on plants grown under low UV-B, whereas reproduction of green peach aphids in both plant light sources was equally poor. These results are likely related to the different specialisation-dependent sensitivities of the two species. The aphids also affected plant chemistry. High numbers of cabbage aphid progeny on low-UV-B plants led to decreased indolyl glucosinolate concentrations. The induced change in these glucosinolates may depend on an infestation threshold. UV-B radiation considerably impacts plant traits and subsequently affects specialist phloem-feeding aphids, whereas aphid growth forces broccoli to generate specific defence responses.

  9. Nutritional physiology of life-history trade-offs: how food protein-carbohydrate content influences life-history traits in the wing-polymorphic cricket Gryllus firmus.

    Science.gov (United States)

    Clark, Rebecca M; Zera, Anthony J; Behmer, Spencer T

    2015-01-15

    Although life-history trade-offs result from the differential acquisition and allocation of nutritional resources to competing physiological functions, many aspects of this topic remain poorly understood. Wing-polymorphic insects, which possess alternative morphs that trade off allocation to flight capability versus early reproduction, provide a good model system for exploring this topic. In this study, we used the wing-polymorphic cricket Gryllus firmus to test how expression of the flight capability versus reproduction trade-off was modified across a heterogeneous protein-carbohydrate nutritional landscape. Newly molted adult female long- and short-winged crickets were given one of 13 diets with different concentrations and ratios of protein and digestible carbohydrate; for each cricket, we measured consumption patterns, growth and allocation to reproduction (ovary mass) versus flight muscle maintenance (flight muscle mass and somatic lipid stores). Feeding responses in both morphs were influenced more by total macronutrient concentration than by protein-carbohydrate ratio, except at high-macronutrient concentration, where protein-carbohydrate balance was important. Mass gain tended to be greatest on protein-biased diets for both morphs, but was consistently lower across all diets for long-winged females. When long-winged females were fed high-carbohydrate foods, they accumulated greater somatic lipid stores; on high-protein foods, they accumulated greater somatic protein stores. Food protein-carbohydrate content also affected short-winged females (selected for early reproductive onset), which showed dramatic increases in ovary size, including ovarian stores of lipid and protein, on protein-biased foods. This is the first study to show how the concentration and ratio of dietary protein and carbohydrate affects consumption and allocation to key physiological features associated with the reproduction-dispersal life-history trade-off. © 2015. Published by The

  10. Biometric morphing: a novel technique for the analysis of morphologic outcomes after facial surgery.

    Science.gov (United States)

    Pahuta, Markian A; Mainprize, James G; Rohlf, F James; Antonyshyn, Oleh M

    2009-01-01

    The results of facial surgery are intuitively judged in terms of the visible changes in facial features or proportions. However, describing these morphologic outcomes objectively remains a challenge. Biometric morphing addresses this issue by merging statistical shape analysis and image processing. This study describes the implementation of biometric morphing in describing the average morphologic result of facial surgery. The biometric morphing protocol was applied to pre- and postoperative images of the following: (1) 40 dorsal hump reduction rhinoplasties and (2) 20 unilateral enophthalmos repairs. Pre- and postoperative average images (average morphs) were generated. The average morphs provided an objective rendering of nasal and periorbital morphology, which summarized the average features and extent of deformity in a population of patients. Subtle alterations in morphology after surgery, which would otherwise be difficult to identify or demonstrate, were clearly illustrated. Biometric morphing is an effective instrument for describing average facial morphology in a population of patients.

  11. Dynamics and Control of a Quadrotor with Active Geometric Morphing

    Science.gov (United States)

    Wallace, Dustin A.

    Quadrotors are manufactured in a wide variety of shapes, sizes, and performance levels to fulfill a multitude of roles. Robodub Inc. has patented a morphing quadrotor which will allow active reconfiguration between various shapes for performance optimization across a wider spectrum of roles. The dynamics of the system are studied and modeled using Newtonian Mechanics. Controls are developed and simulated using both Linear Quadratic and Numerical Nonlinear Optimal control for a symmetric simplificiation of the system dynamics. Various unique vehicle capabilities are investigated, including novel single-throttle flight control using symmetric geometric morphing, as well as recovery from motor loss by reconfiguring into a trirotor configuration. The system dynamics were found to be complex and highly nonlinear. All attempted control strategies resulted in controllability, suggesting further research into each may lead to multiple viable control strategies for a physical prototype.

  12. Development of morphing algorithms for Histfactory using information geometry

    Energy Technology Data Exchange (ETDEWEB)

    Bandyopadhyay, Anjishnu; Brock, Ian [University of Bonn (Germany); Cranmer, Kyle [New York University (United States)

    2016-07-01

    Many statistical analyses are based on likelihood fits. In any likelihood fit we try to incorporate all uncertainties, both systematic and statistical. We generally have distributions for the nominal and ±1 σ variations of a given uncertainty. Using that information, Histfactory morphs the distributions for any arbitrary value of the given uncertainties. In this talk, a new morphing algorithm will be presented, which is based on information geometry. The algorithm uses the information about the difference between various probability distributions. Subsequently, we map this information onto geometrical structures and develop the algorithm on the basis of different geometrical properties. Apart from varying all nuisance parameters together, this algorithm can also probe both small (< 1 σ) and large (> 2 σ) variations. It will also be shown how this algorithm can be used for interpolating other forms of probability distributions.

  13. Steering Angle Function Algorithm of Morphing of Residential Area

    Directory of Open Access Journals (Sweden)

    XIE Tian

    2015-07-01

    Full Text Available A residential area feature morphing method based on steering angle function is presented. To residential area with the same representation under two different scales,transforming the representation of the residential area polygon from vector coordinates to steering angle function,then using the steering angle function to match,and finding out the similarity and the differences between the residential areas under different scale to get the steering angle function of the the residential areas under any middle scale,the final,transforming the middle scale steering angle function to vector coordinates form,and get the middle shape interpolation of the the residential area polygon.Experimental results show:the residential area morphing method by using steering angle function presented can realize the continuous multi-scale representation under the premise of keeping in shape for the residential area with the rectangular boundary features.

  14. Individualized Human CAD Models: Anthropmetric Morphing and Body Tissue Layering

    Science.gov (United States)

    2014-07-31

    Part Flow Chart of the Interaction among VBA Macros, Excel® Spreadsheet, and SolidWorks Front View of the Male and Female Soldier CAD Model...yellow highlighting. The spreadsheet is linked to the CAD model by macros created with the Visual Basic for Application ( VBA ) editor in Microsoft Excel...basically three working parts to the anthropometric morphing that are all interconnected ( VBA macros, Excel spreadsheet, and SolidWorks). The flow

  15. Development of Morphing for Studies of HEFT with ATLAS

    CERN Document Server

    Kaluza, Adam; The ATLAS collaboration

    2015-01-01

    Measurements with e.g. an effective Lagrangian can have a large set of free coupling parameters on which the signal strength and kinematics depend on. These parameters do not factorize trivially into individual observables. Therefore, it is necessary to build a signal model taking all parameters simultaneously into account and modelling all interference effects. With the development of the Morphing method in ATLAS it is possible to predict signal cross section and distributions in such a theoretical framework.

  16. Morphing: A Novel Approach to Astronaut Suit Sizing

    Science.gov (United States)

    Margerum, Sarah; Clowers, Kurt; Rajulu, Sudhakar

    2006-01-01

    The fitting of a spacesuit to an astronaut is an iterative process consisting of two parts. The first uses anthropometric data to provide an approximation of the suit components that will fit the astronaut. The second part is the subjective fitting, where small adjustments are made based on the astronaut s preference. By providing a better approximation of the correct suit components, the entire fit process time can be reduced significantly. The goals of this project are twofold: (1) To evaluate the effectiveness of the existing sizing algorithm for the Mark III Hybrid suit and (2) to determine what additional components are needed in order to provide adequate sizing for the existing astronaut population. A single subject was scanned using a 3D whole-body scanner (VITUS 3D) in the Mark III suit in eight different poses and four subjects in minimal clothing were also scanned in similar poses. The 3D external body scans of the suit and the subject are overlaid and visually aligned in a customized MATLAB program. The suit components were contracted or expanded linearly along the subjects limbs to match the subjects segmental lengths. Two independent measures were obtained from the morphing program on four subjects and compared with the existing sizing information. Two of the four subjects were in correspondence with the sizing algorithm and morphing results. The morphing outcome for a third subject, incompatible with the suit, suggested that an additional arm element at least 6 inches smaller than the existing smallest suit component would need to be acquired. The morphing result of the fourth subject, deemed incompatible with the suit using the sizing algorithm, indicated a different suit configuration which would be compatible. This configuration matched with the existing suit fit check data.

  17. Morphing Structures, Mechanosensors, and Osmotic Motors in Plants

    Science.gov (United States)

    2014-07-24

    closure of the Venus flytrap represents the nonmuscular movement based on hydraulics and mechanical elasticity. The nastic movements in various plants ...SECURITY CLASSIFICATION OF: We created a digital system for measurements of extremely low electrical currents in plants . We analyzed and evaluated...equivalent electrical circuits in clusters of plant cells and in whole plants and studied the concerted movements and morphing structures induced by

  18. Morphing in rhinoplasty: predictive accuracy and reasons for use.

    Science.gov (United States)

    Goffart, Y

    2010-01-01

    A critical step in successful surgery is the precise definition of the surgical goals by both the patient and the surgeon. Much of the discussion between the surgeon and the patient is about managing expectations. Today's technology provides an easy way of forecasting the result of a rhinoplasty procedure, as long as surgeons themselves do the morphing. In a retrospective study of 133 rhinoplasty patients, we analysed the correlation between pre-operative morphing and surgical results. The match was good (identical or similar) in 85.7% of patients (n = 114), approximate in 11.3% of patients (n = 15), and poor in 3% (n = 4). There was a significant correlation with an increased need for adjunctive procedures or revision surgery when the match was approximate or poor. The approach also proved useful for careful pre-operative planning by the surgeon, requiring detailed facial analysis and the establishment of precise goals before surgery. Overly optimistic morphing is not recommended given the risk of raising false expectations.

  19. Biological control of tortricids and aphids in strawberries

    DEFF Research Database (Denmark)

    Sigsgaard, Lene; Enkegaard, Annie; Eilenberg, Jørgen

    Cropping practice and biological control can contribute to reduced pesticide use in strawberries. Organic strawberries are less attacked by strawberry tortricid and buckwheat flower strips can augment its natural enemies. Against shallot aphid the two-spot ladybird is promising....

  20. Nonlinear Dynamics of Z-Shaped Folding Wings with 1:1 Inner Resonance

    Science.gov (United States)

    Guo, Xiangying; Zhang, Yang; Zhang, Wei; Sun, Lin; Chen, Shuping

    Predicting the nonlinear vibration responses of a Z-shaped folding wing during the morphing process is a prerequisite for structural design analysis. Therefore, the present study focuses on the nonlinear dynamical characteristics of a Z-shaped folding wing. The folding wing is divided into three carbon fiber composite plates connected by rigid hinges. The nonlinear dynamic equations of the system are derived using Hamilton’s principle based on the von Kármán equations and classical laminate plate theory. The mode shape functions of the system are then obtained using finite element analysis. Galerkin’s approach is employed to discretize the partial differential governing equations into a two-degree-of-freedom nonlinear system. The case of 1:1 inner resonance is considered. The method of multiple scales is employed to obtain the averaged equations of the system. Finally, numerical simulation is performed to investigate the nonlinear dynamical characteristics of the system. Bifurcation diagrams and wave-form diagrams illustrate the different motions of the Z-shaped folding wing, including periodic and chaotic motions under given conditions. The influence of transverse excitations on the bifurcations and chaotic motion of the Z-shaped folding wing is investigated numerically.

  1. Genetic control of floral morph in tristylous Pickerelweed (Pontederia cordata L.).

    Science.gov (United States)

    Gettys, Lyn A; Wofford, David S

    2008-01-01

    Pickerelweed (Pontederia cordata L.) is a diploid (2n = 2x = 16) tristylous aquatic perennial. Populations usually contain 3 floral morphs that differ reciprocally in style length and anther height (referred to as the long-, mid-, and short-styled morphs, hereafter L-, M-, and S-morphs). The floral polymorphism promotes disassortative mating among the 3 floral morphs and is maintained in populations by negative frequency-dependent selection. The objective of this study was to determine the number of loci, number of alleles, and gene action controlling floral morph in pickerelweed. Three parental lines (one each of the L-, M-, and S-morph) were used to create S1 and F1 populations. F2 populations were produced through self-pollination of F1 plants. Progeny ratios of S1, F1, and F2 generations revealed that tristyly is controlled by 2 diallelic loci (S and M) with dominant gene action. The S locus is epistatic to the M locus, with the S-morph produced by plants with the dominant S allele (genotype S _ _ _). Plants with recessive alleles at the S locus were either L-morph (ssmm) or M-morph (ssM_). The results of this experiment demonstrate that the inheritance of tristyly in pickerelweed is the same as previously reported for several tristylous species in the Lythraceae and Oxalidaceae.

  2. Flow Quality Analysis of Shape Morphing Structures for Hypersonic Ground Testing Applications

    Data.gov (United States)

    National Aeronautics and Space Administration — Background: Shape morphing, high temperature, ceramic structural materials are now becoming available and can revolutionize ground testing by providing dynamic flow...

  3. WINGS Data Release

    DEFF Research Database (Denmark)

    Moretti, A.; Poggianti, B. M.; Fasano, G.

    2014-01-01

    Context. To effectively investigate galaxy formation and evolution, it is of paramount importance to exploit homogeneous data for large samples of galaxies in different environments. Aims. The WIde-field Nearby Galaxy-cluster Survey (WINGS) project aim is to evaluate physical properties of galaxies...... in a complete sample of low redshift clusters to be used as reference sample for evolutionary studies. The WINGS survey is still ongoing and the original dataset will be enlarged with new observations. This paper presents the entire collection of WINGS measurements obtained so far. Methods. We decided to make......, and on the cluster redshift, reaching on average 90% at V ≲ 21.7. Near-infrared photometric catalogs for 26 (in K) and 19 (in J) clusters are part of the database and the number of sources is 962 344 in K and 628 813 in J. Here again the completeness depends on the data quality, but it is on average higher than 90...

  4. Mulches reduce aphid-borne viruses and whiteflies in cantaloupe

    OpenAIRE

    Summers, Charles G.; Mitchell, Jeffrey P.; Stapleton, James J.

    2005-01-01

    We compared reflective plastic and wheat straw mulches with conventional bare soil for managing aphid-borne virus diseases and silverleaf whitefly in cantaloupe. The occurrence of aphid-borne virus diseases was significantly reduced with both mulches as opposed to bare soil, and reflective plastic performed better than wheat straw. Silverleaf whitefly numbers, both adults and nymphs, were reduced equally by plastic mulch and wheat straw, and were significantly lower than with bare soil. Refle...

  5. Aphids alter host-plant nitrogen isotope fractionation

    Science.gov (United States)

    Wilson, Alex C. C.; Sternberg, Leonel da S. L.; Hurley, Katherine B.

    2011-01-01

    Plant sap-feeding insects and blood-feeding parasites are frequently depleted in 15N relative to their diet. Unfortunately, most fluid-feeder/host nitrogen stable-isotope studies simply report stable-isotope signatures, but few attempt to elucidate the mechanism of isotopic trophic depletion. Here we address this deficit by investigating the nitrogen stable-isotope dynamics of a fluid-feeding herbivore-host plant system: the green peach aphid, Myzus persicae, feeding on multiple brassicaceous host plants. M. persicae was consistently more than 6‰ depleted in 15N relative to their hosts, although aphid colonized plants were 1.5‰ to 2.0‰ enriched in 15N relative to uncolonized control plants. Isotopic depletion of aphids relative to hosts was strongly related to host nitrogen content. We tested whether the concomitant aphid 15N depletion and host 15N enrichment was coupled by isotopic mass balance and determined that aphid 15N depletion and host 15N enrichment are uncoupled processes. We hypothesized that colonized plants would have higher nitrate reductase activity than uncolonized plants because previous studies had demonstrated that high nitrate reductase activity under substrate-limiting conditions can result in increased plant δ15N values. Consistent with our hypothesis, nitrate reductase activity in colonized plants was twice that of uncolonized plants. This study offers two important insights that are likely applicable to understanding nitrogen dynamics in fluid-feeder/host systems. First, isotopic separation of aphid and host depends on nitrogen availability. Second, aphid colonization alters host nitrogen metabolism and subsequently host nitrogen stable-isotope signature. Notably, this work establishes a metabolic framework for future hypothesis-driven studies focused on aphid manipulation of host nitrogen metabolism. PMID:21646532

  6. Seed treatments with thiamine reduce the performance of generalist and specialist aphids on crop plants.

    Science.gov (United States)

    Hamada, A M; Fatehi, J; Jonsson, L M V

    2018-02-01

    Thiamine is a vitamin that has been shown to act as a trigger to activate plant defence and reduce pathogen and nematode infection as well as aphid settling and reproduction. We have here investigated whether thiamine treatments of seeds (i.e. seed dressing) would increase plant resistance against aphids and whether this would have different effects on a generalist than on specialist aphids. Seeds of wheat, barley, oat and pea were treated with thiamine alone or in combination with the biocontrol bacteria Pseudomonas chlororaphis MA 342 (MA 342). Plants were grown in climate chambers. The effects of seed treatment on fecundity, host acceptance and life span were studied on specialist aphids bird cherry-oat aphid (Rhopalosiphum padi L.) and pea aphid (Acyrthosiphon pisum Harris) and on the generalist green peach aphid (Myzus persicae, Sulzer). Thiamine seed treatments reduced reproduction and host acceptance of all three aphid species. The number of days to reproduction, the length of the reproductive life, the fecundity and the intrinsic rate of increase were found reduced for bird cherry-oat aphid after thiamine treatment of the cereal seeds. MA 342 did not have any effect in any of the plant-aphid combinations, except a weak decrease of pea aphid reproduction on pea. The results show that there are no differential effects of either thiamine or MA 342 seed treatments on specialist and generalist aphids and suggest that seed treatments with thiamine has a potential in aphid pest management.

  7. Host Plants Indirectly Influence Plant Virus Transmission by Altering Gut Cysteine Protease Activity of Aphid Vectors*

    Science.gov (United States)

    Pinheiro, Patricia V.; Ghanim, Murad; Rebelo, Ana Rita; Santos, Rogerio S.; Orsburn, Benjamin C.; Gray, Stewart

    2017-01-01

    The green peach aphid, Myzus persicae, is a vector of the Potato leafroll virus (PLRV, Luteoviridae), transmitted exclusively by aphids in a circulative manner. PLRV transmission efficiency was significantly reduced when a clonal lineage of M. persicae was reared on turnip as compared with the weed physalis, and this was a transient effect caused by a host-switch response. A trend of higher PLRV titer in physalis-reared aphids as compared with turnip-reared aphids was observed at 24 h and 72 h after virus acquisition. The major difference in the proteomes of these aphids was the up-regulation of predicted lysosomal enzymes, in particular the cysteine protease cathepsin B (cathB), in aphids reared on turnip. The aphid midgut is the site of PLRV acquisition, and cathB and PLRV localization were starkly different in midguts of the aphids reared on the two host plants. In viruliferous aphids that were reared on turnip, there was near complete colocalization of cathB and PLRV at the cell membranes, which was not observed in physalis-reared aphids. Chemical inhibition of cathB restored the ability of aphids reared on turnip to transmit PLRV in a dose-dependent manner, showing that the increased activity of cathB and other cysteine proteases at the cell membrane indirectly decreased virus transmission by aphids. Understanding how the host plant influences virus transmission by aphids is critical for growers to manage the spread of virus among field crops. PMID:27932519

  8. The Protease Inhibitor CI2c Gene Induced by Bird Cherry-Oat Aphid in Barley Inhibits Green Peach Aphid Fecundity in Transgenic Arabidopsis.

    Science.gov (United States)

    Losvik, Aleksandra; Beste, Lisa; Mehrabi, Sara; Jonsson, Lisbeth

    2017-06-20

    Aphids are phloem feeders that cause large damage globally as pest insects. They induce a variety of responses in the host plant, but not much is known about which responses are promoting or inhibiting aphid performance. Here, we investigated whether one of the responses induced in barley by the cereal aphid, bird cherry-oat aphid ( Rhopalosiphum padi L.) affects aphid performance in the model plant Arabidopsis thaliana L. A barley cDNA encoding the protease inhibitor CI2c was expressed in A. thaliana and aphid performance was studied using the generalist green peach aphid ( Myzus persicae Sulzer). There were no consistent effects on aphid settling or preference or on parameters of life span and long-term fecundity. However, short-term tests with apterous adult aphids showed lower fecundity on three of the transgenic lines, as compared to on control plants. This effect was transient, observed on days 5 to 7, but not later. The results suggest that the protease inhibitor is taken up from the tissue during probing and weakly inhibits fecundity by an unknown mechanism. The study shows that a protease inhibitor induced in barley by an essentially monocot specialist aphid can inhibit a generalist aphid in transgenic Arabidopsis.

  9. The Protease Inhibitor CI2c Gene Induced by Bird Cherry-Oat Aphid in Barley Inhibits Green Peach Aphid Fecundity in Transgenic Arabidopsis

    Directory of Open Access Journals (Sweden)

    Aleksandra Losvik

    2017-06-01

    Full Text Available Aphids are phloem feeders that cause large damage globally as pest insects. They induce a variety of responses in the host plant, but not much is known about which responses are promoting or inhibiting aphid performance. Here, we investigated whether one of the responses induced in barley by the cereal aphid, bird cherry-oat aphid (Rhopalosiphum padi L. affects aphid performance in the model plant Arabidopsis thaliana L. A barley cDNA encoding the protease inhibitor CI2c was expressed in A. thaliana and aphid performance was studied using the generalist green peach aphid (Myzus persicae Sulzer. There were no consistent effects on aphid settling or preference or on parameters of life span and long-term fecundity. However, short-term tests with apterous adult aphids showed lower fecundity on three of the transgenic lines, as compared to on control plants. This effect was transient, observed on days 5 to 7, but not later. The results suggest that the protease inhibitor is taken up from the tissue during probing and weakly inhibits fecundity by an unknown mechanism. The study shows that a protease inhibitor induced in barley by an essentially monocot specialist aphid can inhibit a generalist aphid in transgenic Arabidopsis.

  10. Does aphid salivation affect phloem sieve element occlusion in vivo?

    Science.gov (United States)

    Medina-Ortega, Karla J; Walker, G P

    2013-12-01

    To protect against loss of photo-assimilate-rich phloem sap, plants have evolved several mechanisms to plug phloem sieve tubes in response to damage. In many Fabaceae, each sieve element contains a discrete proteinaceous body called a forisome, which, in response to damage, rapidly transforms from a condensed configuration that does not impede the flow of sap to a dispersed configuration that plugs the sieve element. Aphids and other specialized phloem sap feeders can ingest phloem sap from a single sieve element for hours or days, and to do this, they must be able to suppress or reverse phloem plugging. A recent study provided in vitro evidence that aphid saliva can reverse forisome plugs. The present study tested this hypothesis in vivo by inducing forisome plugs which triggered aphids to switch behaviour from phloem sap ingestion to salivation into the sieve element. After salivating into the sieve element for various periods of time, the aphids were instantaneously cryofixed (freeze fixed) in situ on their leaf. The state of the forisome was then determined in the penetrated sieve element and in nearby non-penetrated sieve elements which served as controls for sieve elements not subjected to direct aphid salivation. Forisomes were almost always in close contact with the stylet tips and thus came into direct contact with the saliva. Nonetheless, forisome plugs in the penetrated sieve element did not revert back to a non-plugging state any faster than those in neighbouring sieve elements that were not subjected to direct aphid salivation.

  11. Aphid (Hemiptera: Aphididae) species determined in Çanakkale Province with a new record for the aphid fauna of Turkey

    OpenAIRE

    KÖK, Şahin; KASAP, İsmail; ÖZDEMİR, Işıl

    2016-01-01

    As a result of a study conducted to determine aphid species on herbaceous plants, shrubs and trees in cultivated and uncultivated areas from 2013 to 2015 in Çanakkale Province, Turkey, 39 species and one subspecies in 24 genera of Aphididae family were determined. Of these species, Aphis sedi Kaltenbach, 1843 collected from Lampranthus sp. (Aizoaceae) was new record for the aphid fauna of Turkey. Also, Helianthus annuus L. (Asteraceae) and Pimpinella saxifraga L. (Apiaceae) were determined as...

  12. Agronomy of strip intercropping broccoli with alyssum for biological control of aphids

    Science.gov (United States)

    Organic broccoli growers in California typically control aphids by intercropping broccoli with strips of alyssum (Lobularia maritima (L.) Desv.) which attracts hoverflies (Diptera: Syrphidae) that are important predators of aphids. A three year study with transplanted organic broccoli in Salinas, ...

  13. Preparing soft-bodied arthropods for microscope examination: Aphids (Insecta: Hemiptera: Aphididae)

    Science.gov (United States)

    Proper identification of aphids (Hemiptera: Aphididae) require preparation of the specimen on a microscope slide. This training video provides visual instruction on how to prepare aphid specimens on microscope slides for examination and indentification. Steps ranging from collection, specimen clear...

  14. WHEN COMPASSION GROWS WINGS

    African Journals Online (AJOL)

    Nicky

    antiretroviral roll-out in full swing, the. WHEN COMPASSION GROWS WINGS. The free time and expertise given by its deeply committed core of professional volunteers. (including pilots) is the lifeblood of the operation. Red Cross Air Mercy Service volunteer, German national Dr Florian Funk, at the AMS Durban base.

  15. Twisted Winged Endoparasitoids

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 10. Twisted Winged Endoparasitoids - An Enigma for Entomologists. Alpana Mazumdar. General Article Volume 9 Issue 10 October 2004 pp 19-24. Fulltext. Click here to view fulltext PDF. Permanent link:

  16. Phloem protein partners of Cucurbit aphid borne yellows virus: possible involvement of phloem proteins in virus transmission by aphids.

    Science.gov (United States)

    Bencharki, B; Boissinot, S; Revollon, S; Ziegler-Graff, V; Erdinger, M; Wiss, L; Dinant, S; Renard, D; Beuve, M; Lemaitre-Guillier, C; Brault, V

    2010-06-01

    Poleroviruses are phytoviruses strictly transmitted by phloem-feeding aphids in a circulative and nonpropagative mode. During ingestion, aphids sample virions in sieve tubes along with sap. Therefore, any sap protein bound to virions will be acquired by the insects and could potentially be involved in the transmission process. By developing in vitro virus-overlay assays on sap proteins collected from cucumber, we observed that approximately 20 proteins were able to bind to purified particles of Cucurbit aphid borne yellows virus (CABYV). Among them, eight proteins were identified by mass spectrometry. The role of two candidates belonging to the PP2-like family (predominant lectins found in cucurbit sap) in aphid transmission was further pursued by using purified orthologous PP2 proteins from Arabidopsis. Addition of these proteins to the virus suspension in the aphid artificial diet greatly increased virus transmission rate. This shift was correlated with an increase in the number of viral genomes in insect cells and with an increase of virion stability in vitro. Surprisingly, increase of the virus transmission rate was also monitored after addition of unrelated proteins in the aphid diet, suggesting that any soluble protein at sufficiently high concentration in the diet and acquired together with virions could stimulate virus transmission.

  17. Toxin delivery by the coat protein of an aphid-vectored plant virus provides plant resistance to aphids.

    Science.gov (United States)

    Bonning, Bryony C; Pal, Narinder; Liu, Sijun; Wang, Zhaohui; Sivakumar, S; Dixon, Philip M; King, Glenn F; Miller, W Allen

    2014-01-01

    The sap-sucking insects (order Hemiptera), including aphids, planthoppers, whiteflies and stink bugs, present one of the greatest challenges for pest management in global agriculture. Insect neurotoxins offer an alternative to chemical insecticides for controlling these pests, but require delivery into the insect hemocoel. Here we use the coat protein of a luteovirus, an aphid-vectored plant virus, to deliver a spider-derived, insect-specific toxin that acts within the hemocoel. The luteovirid coat protein is sufficient for delivery of fused proteins into the hemocoel of pea aphids, Acyrthosiphon pisum, without virion assembly. We show that when four aphid pest species-A. pisum, Rhopalosiphum padi, Aphis glycines and Myzus persicae-feed on a recombinant coat protein-toxin fusion, either in an experimental membrane sachet or in transgenic Arabidopsis plants, they experience significant mortality. Aphids fed on these fusion proteins showed signs of neurotoxin-induced paralysis. Luteovirid coat protein-insect neurotoxin fusions represent a promising strategy for transgenic control of aphids and potentially other hemipteran pests.

  18. Tetramorium tsushimae Ants Use Methyl Branched Hydrocarbons of Aphids for Partner Recognition.

    Science.gov (United States)

    Sakata, Itaru; Hayashi, Masayuki; Nakamuta, Kiyoshi

    2017-10-01

    In mutualisms, partner discrimination is often the most important challenge for interacting organisms. The interaction between ants and aphids is a model system for studying mutualisms; ants are provided with honeydew by aphids and, in turn, the ants offer beneficial services to the aphids. To establish and maintain this system, ants must discriminate mutualistic aphid species correctly. Although recent studies have shown that ants recognize aphids as mutualistic partners based on their cuticular hydrocarbons (CHCs), it was unclear which CHCs are involved in recognition. Here, we tested whether the n-alkane or methylalkane fraction, or both, of aphid CHCs were utilized as partner recognition cues by measuring ant aggressiveness toward these fractions. When workers of Tetramorium tsushimae ants were presented with dummies coated with n-alkanes of their mutualistic aphid Aphis craccivora, ants displayed higher levels of aggression than to dummies treated with total CHCs or methyl alkanes of A. craccivora; responses to dummies treated with n-alkanes of A. craccivora were similar to those to control dummies or dummies treated with the CHCs of the non-mutualistic aphid Acyrthosiphon pisum. By contrast, ants exhibited lower aggression to dummies treated with either total CHCs or the methylalkane fraction of the mutualistic aphid than to control dummies or dummies treated with CHCs of the non-mutualistic aphid. These results suggest that T. tsushimae ants use methylalkanes of the mutualistic aphid's CHCs to recognize partners, and that these ants do not recognize aphids as partners on the basis of n-alkanes.

  19. National Plant Diagnostic Network, Taxonomic training videos: Introduction to AphID

    Science.gov (United States)

    Training is a critical part of aphid (Hemiptera: Aphididae) identification. This video provides visual instruction on the use of the expert system, AphID, for aphid examination and identification. The video demonstrates the use of different training modules that allow the user to gain familiarity wi...

  20. Aphidius gifuensis: a promising parasitoid for biological control of two important aphid species in sweet pepper

    NARCIS (Netherlands)

    Messelink, G.J.; Bloemhard, C.M.J.; Hoogerbrugge, H.; Schelt, van J.

    2011-01-01

    The parasitoid Aphidius gifuensis is able to parasitize both the green peach aphid Myzus persicae and the foxglove aphid Aulacorthum solani in sweet pepper. In a greenhouse experiment we showed that rates of parasitism on green peach aphids alone were equal to the commonly used Aphidius colemani,

  1. Comparison of transmission efficiency of different isolates of Potato virus Y among three aphid vectors

    Science.gov (United States)

    Potato virus Y (PVY) strains are transmitted by different aphid species in a non-persistent, non-circulative manner. Green peach aphid (GPA, Myzus persicae Sulzer; Aphididae, Macrosiphini) is the most efficient vector in laboratory studies, but potato aphid (PA, Macrosiphum euphorbiae Thomas; Aphidi...

  2. Suppression of plant defenses by a Myzus persicae (green peach aphid) salivary effector protein.

    Science.gov (United States)

    Elzinga, Dezi A; De Vos, Martin; Jander, Georg

    2014-07-01

    The complex interactions between aphids and their host plant are species-specific and involve multiple layers of recognition and defense. Aphid salivary proteins, which are released into the plant during phloem feeding, are a likely mediator of these interactions. In an approach to identify aphid effectors that facilitate feeding from host plants, eleven Myzus persicae (green peach aphid) salivary proteins and the GroEL protein of Buchnera aphidicola, a bacterial endosymbiont of this aphid species, were expressed transiently in Nicotiana tabacum (tobacco). Whereas two salivary proteins increased aphid reproduction, expression of three other aphid proteins and GroEL significantly decreased aphid reproduction on N. tabacum. These effects were recapitulated in stable transgenic Arabidopsis thaliana plants. Further experiments with A. thaliana expressing Mp55, a salivary protein that increased aphid reproduction, showed lower accumulation of 4-methoxyindol-3-ylmethylglucosinolate, callose and hydrogen peroxide in response to aphid feeding. Mp55-expressing plants also were more attractive for aphids in choice assays. Silencing Mp55 gene expression in M. persicae using RNA interference approaches reduced aphid reproduction on N. tabacum, A. thaliana, and N. benthamiana. Together, these results demonstrate a role for Mp55, a protein with as-yet-unknown molecular function, in the interaction of M. persicae with its host plants.

  3. National Plant Diagnostic Network, Taxonomic training videos: Aphids under the microscope - overview

    Science.gov (United States)

    Training is a critical part of aphid (Hemiptera: Aphididae) identification. This training video provides provides an overview of general aphid morphology by using a compound microscope. The narrator discusses and highlights structures on the aphid that are important to make a species identification....

  4. Effects on the non-target aphid Aphis Gossypii Glover (Homoptera ...

    African Journals Online (AJOL)

    bych76-zhjh77

    2012-05-22

    May 22, 2012 ... parasitoids and their honeydew is an important energy source for several arthropods. Analyses of the impact of transgenic plants expressing Cry toxins on aphids gave variable results ranging from minor negative effects on aphid survival and fecundity to significant beneficial effects on aphid populations ...

  5. Variable isotopic compositions of host plant populations preclude assessment of aphid overwintering sites

    Science.gov (United States)

    Soybean aphid (Aphis glycines Matsumura) is a pest of soybean in the northern Midwest whose migratory patterns have been difficult to quantify. Improved knowledge of soybean aphid overwintering sites could facilitate the development of control efforts with exponential impacts on aphid densities on a...

  6. Differences in Mating Propensity Between Immature Female Color Morphs in the Damselfly Ischnura elegans (Insecta : Odonata)

    NARCIS (Netherlands)

    Hammers, Martijn; Ana Sanchez-Guillen, Rosa; Van Gossum, Hans

    Female-limited color polymorphisms occur in a variety of animal taxa where excessive male sexual harassment may explain the coexistence of multiple female color morphs. In the color polymorphic damselfly Ischnura elegans, mature and immature female color morphs coexist at the mating site where males

  7. Evaluation of the generality and accuracy of a new mesh morphing procedure for the human femur.

    Science.gov (United States)

    Grassi, Lorenzo; Hraiech, Najah; Schileo, Enrico; Ansaloni, Mauro; Rochette, Michel; Viceconti, Marco

    2011-01-01

    Various papers described mesh morphing techniques for computational biomechanics, but none of them provided a quantitative assessment of generality, robustness, automation, and accuracy in predicting strains. This study aims to quantitatively evaluate the performance of a novel mesh-morphing algorithm. A mesh-morphing algorithm based on radial-basis functions and on manual selection of corresponding landmarks on template and target was developed. The periosteal geometries of 100 femurs were derived from a computed tomography scan database and used to test the algorithm generality in producing finite element (FE) morphed meshes. A published benchmark, consisting of eight femurs for which in vitro strain measurements and standard FE model strain prediction accuracy were available, was used to assess the accuracy of morphed FE models in predicting strains. Relevant parameters were identified to test the algorithm robustness to operative conditions. Time and effort needed were evaluated to define the algorithm degree of automation. Morphing was successful for 95% of the specimens, with mesh quality indicators comparable to those of standard FE meshes. Accuracy of the morphed meshes in predicting strains was good (R(2)>0.9, RMSE%0.05) and partially to the number of landmark used. Producing a morphed mesh starting from the triangularized geometry of the specimen requires on average 10 min. The proposed method is general, robust, automated, and accurate enough to be used in bone FE modelling from diagnostic data, and prospectively in applications such as statistical shape modelling. Copyright © 2010 IPEM. Published by Elsevier Ltd. All rights reserved.

  8. A Morphing Technique Applied to Lung Motions in Radiotherapy: Preliminary Results

    Directory of Open Access Journals (Sweden)

    R. Laurent

    2010-01-01

    Full Text Available Organ motion leads to dosimetric uncertainties during a patient’s treatment. Much work has been done to quantify the dosimetric effects of lung movement during radiation treatment. There is a particular need for a good description and prediction of organ motion. To describe lung motion more precisely, we have examined the possibility of using a computer technique: a morphing algorithm. Morphing is an iterative method which consists of blending one image into another image. To evaluate the use of morphing, Four Dimensions Computed Tomography (4DCT acquisition of a patient was performed. The lungs were automatically segmented for different phases, and morphing was performed using the end-inspiration and the end-expiration phase scans only. Intermediate morphing files were compared with 4DCT intermediate images. The results showed good agreement between morphing images and 4DCT images: fewer than 2 % of the 512 by 256 voxels were wrongly classified as belonging/not belonging to a lung section. This paper presents preliminary results, and our morphing algorithm needs improvement. We can infer that morphing offers considerable advantages in terms of radiation protection of the patient during the diagnosis phase, handling of artifacts, definition of organ contours and description of organ motion.

  9. On the Importance of Morphing Deformation Scheduling for Actuation Force and Energy

    NARCIS (Netherlands)

    De Breuker, R.

    2016-01-01

    Morphing aircraft offer superior properties as compared to non-morphing aircraft. They can achieve this by adapting their shape depending on the requirements of various conflicting flight conditions. These shape changes are often associated with large deformations and strains, and hence dedicated

  10. Aphid Transmission of the Ontario Isolate of Plum Pox Virus.

    Science.gov (United States)

    Lowery, D Thomas; Vickers, Patricia M; Bittner, Lori A; Stobbs, Lorne W; Foottit, Robert G

    2015-10-01

    Utilization of timed virus acquisition access probes in studies of plum pox virus (PPV) transmission by aphids demonstrated that endemic species transmitted the virus readily from plum, Prunus domestica (L.) Batsch; peach, P. persica (L.); or dwarf flowering almond, P. glandulosa Thunberg., to peach seedlings. The green peach aphid, Myzus persicae (Sulzer), was shown to be the most efficient vector. Acquisition of virus by green peach aphids from infected peach leaves resulted in 18-28% infected peach seedlings, while aphids previously fed on infected leaves of plum transferred virus to 36% of peach seedlings. Although the spirea aphid, Aphis spiraecola (Patch), was a less efficient vector than M. persicae it is perhaps more important for the spread of PPV due to its greater abundance and occurrence earlier in the season when peach trees are thought to be more susceptible to infection. Virus transmission rates varied depending on the virus source and healthy test plant species. In contrast to many previous studies, aphid inoculation of the experimental host Nicotiana benthamiana Domin occurred at a low rate, never exceeding 4%. Acquisition of PPV by M. persicae from infected peach fruit was greatly reduced compared with acquisition from leaves. The results of this research indicate that the Ontario isolate of PPV-D is readily transmissible by aphids to peach and natural spread of the virus needs to be considered in future management or eradication programs. © Her Majesty in Right of Canada, as represented by the Minister of Agriculture and Agri-Food Canada. Published by Oxford University Press on behalf of Entomological Society of America.

  11. Cereal aphid colony turnover and persistence in winter wheat.

    Directory of Open Access Journals (Sweden)

    Linton Winder

    Full Text Available An understanding of spatial and temporal processes in agricultural ecosystems provides a basis for rational decision-making with regards to the management and husbandry of crops, supporting the implementation of integrated farming strategies. In this study we investigated the spatial and temporal distribution of aphid pests (Sitobion avenae and Metopolophium dirhodum within winter wheat fields. Using an intensive sampling programme we investigated distributions at both the small (single shoot and large (field scales. Within two fields, a grid with 82 locations was established (area 120 m by 168 m. At each location, 25 shoots were individually marked and aphid counts by observation conducted on 21 and 22 occasions as the crop matured, resulting in 43,050 and 45,100 counts being conducted in the two fields respectively. We quantified field scale spatial distributions, demonstrating that spatial pattern generally emerged, with temporal stability being both species- and field- dependent. We then measured turnover of colonies at the small (individual shoot and large (field scales by comparing consecutive pairs of sampling occasions. Four turnover categories were defined: Empty (no aphids recorded on either occasion; Colonised (aphids recorded on the second occasion but not the first; Extinction (aphids recorded on the first occasion but not the second; Stable (aphids recorded on both occasions. At the field scale, population stability soon established, but, at the small scale there was a consistently high proportion of unoccupied shoots with considerable colonisation and extinction and low stability. The redistribution of aphids within the crop at the local scale is a vulnerability which could be used to disrupt population development--by mediating exposure to ground-active natural enemies and by incurring a metabolic cost caused by the physiological demands to re-establish on a nearby host plant.

  12. Investigation of a robust tendon-sheath mechanism for flexible membrane wing application in mini-UAV

    Science.gov (United States)

    Lee, Shian; Tjahjowidodo, Tegoeh; Lee, Hsuchew; Lai, Benedict

    2017-02-01

    Two inherent issues manifest themselves in flying mini-unmanned aerial vehicles (mini-UAV) in the dense area at tropical climate regions, namely disturbances from gusty winds and limited space for deployment tasks. Flexible membrane wing (FMW) UAVs are seen to be potentials to mitigate these problems. FMWs are adaptable to gusty airflow as the wings are able to flex according to the gust load to reduce the effective angle-of-attack, thus, reducing the aerodynamic loads on the wing. On the other hand, the flexible structure is allowing the UAV to fold in a compact package, and later on, the mini-UAV can be deployed instantly from the storage tube, e.g. through a catapult mechanism. This paper discusses the development of an FMW UAV actuated by a tendon-sheath mechanism (TSM). This approach allows the wing to morph to generate a rolling moment, while still allowing the wing to fold. Dynamic characteristics of the mechanism that exhibits the strong nonlinear phenomenon of friction on TSM are modeled and compensated for. A feed-forward controller was implemented based on the identified nonlinear behavior to control the warping position of the wing. The proposed strategy is validated experimentally in a wind tunnel facility by creating a gusty environment that is imitating a realistic gusty condition based upon the results of computational fluid dynamics (CFD) simulation. The results demonstrate a stable and robust wing-warping actuation, even in gusty conditions. Accurate wing-warping can be achieved via the TSM, while also allowing the wings to fold.

  13. New morphing blade section designs and structural solutions for smart blades

    DEFF Research Database (Denmark)

    Karakalas, Anargyros A.; Machairas, Theodore; Solomou, Alexandros

    2015-01-01

    of helicopter and wind turbine blade research have shown the potential of shape morphing in reducing blade loads. Morphing technologies, along with other control concepts, are investigated under Task 2.3 of WP “Lightweight Rotor”, against aerodynamic compliance and requirements of the complete wind turbine.......e. no loss of local/global stiffness or strength and/or fatigue life. The purpose is to report efforts towards the use of new morphing blade section designs and the structural solutions for smart blades (developed in Task 2.3). The objective is to define, assess and demonstrate innovative concepts...... and manufacturing processes constraints. Down selection of design based on results of analysis (for input to Task 2.3) was also performed. Following solutions were investigated:  Morphing blade sections with Shape Memory Alloys (SMA) by University of Patras  Morphing blade sections using an elastomer of zero...

  14. Shape Morphing Adaptive Radiator Technology (SMART) Updates to Techport Entry

    Science.gov (United States)

    Erickson, Lisa; Bertagne, Christopher; Hartl, Darren; Witcomb, John; Cognata, Thomas

    2017-01-01

    The Shape-Morphing Adaptive Radiator Technology (SMART) project builds off the FY16 research effort that developed a flexible composite radiator panel and demonstrated its ability to actuate from SMA's attached to it. The proposed FY17 Shape-Morphing Adaptive Radiator Technology (SMART) project's goal is to 1) develop a practical radiator design with shape memory alloys (SMAs) bonded to the radiator's panel, and 2) build a multi-panel radiator prototype for subsequent system level thermal vacuum tests. The morphing radiator employs SMA materials to passively change its shape to adapt its rate of heat rejection to vehicle requirements. Conceptually, the radiator panel has a naturally closed position (like a cylinder) in a cold environment. Whenever the radiator's temperature gradually rises, SMA's affixed to the face sheet will pull the face sheet open a commensurate amount - increasing the radiators view to space and causing it to reject more heat. In a vehicle, the radiator's variable heat rejection capabilities would reduce the number of additional heat rejection devices in a vehicle's thermal control system. This technology aims to help achieve the required maximum to minimum heat rejection ratio required for manned space vehicles to adopt a lighter, simpler, single loop thermal control architecture (ATCS). Single loop architectures are viewed as an attractive means to reduce mass and complexity over traditional dual-loop solutions. However, fluids generally considered safe enough to flow within crewed cabins (e.g. propylene glycol-water mixtures) have much higher freezing points and viscosities than those used in the external sides of dual loop ATCSs (e.g. Ammonia and HFE7000).

  15. Floral scent emitted by white and coloured morphs in orchids.

    Science.gov (United States)

    Dormont, L; Delle-Vedove, R; Bessière, J-M; Schatz, B

    2014-04-01

    Polymorphism of floral signals, such as colour and odour, is widespread in flowering plants and often considered to be adaptive, reflecting various pollinator preferences for particular floral traits. Several authors have recently hypothesized that particular associations exist between floral colour and scent, which would result from shared biochemistry between these two floral traits. In this study, we compared the chemical composition of floral volatiles emitted by white- and purple-flowered morphs of three different orchid species, including two food-deceptive species (Orchis mascula and Orchis simia) and a food-rewarding species (Anacamptis coriophora fragrans). We found clear interspecific differences in floral odours. As expected from their pollination strategy, the two deceptive orchids showed high inter-individual variation of floral volatiles, whereas the food-rewarding A. c. fragrans showed low variation of floral scent. Floral volatiles did not differ overall between white- and coloured-flowered morphs in O. mascula and A. c. fragrans, while O. simia exhibited different volatile profiles between the two colour morphs. However, a detailed analysis restricted to benzenoid compounds (which are associated with the production of floral anthocyanin pigments) showed that white inflorescences emitted more volatiles of the shikimic pathway than coloured ones, both for O. mascula and O. simia. These results are consistent with the current hypothesis that shared biochemistry creates pleiotropic links between floral colour and scent. Whether intraspecific variation of floral signals actually affects pollinator attraction and influences the reproductive success of these orchids remains to be determined. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Segmented bimorph mirrors for adaptive optics: morphing strategy.

    Science.gov (United States)

    Bastaits, Renaud; Alaluf, David; Belloni, Edoardo; Rodrigues, Gonçalo; Preumont, André

    2014-08-01

    This paper discusses the concept of a light weight segmented bimorph mirror for adaptive optics. It focuses on the morphing strategy and addresses the ill-conditioning of the Jacobian of the segments, which are partly outside the optical pupil. Two options are discussed, one based on truncating the singular values and one called damped least squares, which minimizes a combined measure of the sensor error and the voltage vector. A comparison of various configurations of segmented mirrors was conducted; it is shown that segmentation sharply increases the natural frequency of the system with limited deterioration of the image quality.

  17. Shape-Morphing Materials from Stimuli-Responsive Hydrogel Hybrids.

    Science.gov (United States)

    Jeon, Seog-Jin; Hauser, Adam W; Hayward, Ryan C

    2017-02-21

    The formation of well-defined and functional three-dimensional (3D) structures by buckling of thin sheets subjected to spatially nonuniform stresses is common in biological morphogenesis and has become a subject of great interest in synthetic systems, as such programmable shape-morphing materials hold promise in areas including drug delivery, biomedical devices, soft robotics, and biomimetic systems. Given their ability to undergo large changes in swelling in response to a wide variety of stimuli, hydrogels have naturally emerged as a key type of material in this field. Of particular interest are hybrid systems containing rigid inclusions that can define both the anisotropy and spatial nonuniformity of swelling as well as nanoparticulate additives that can enhance the responsiveness and functionality of the material. In this Account, we discuss recent progress in approaches to achieve well-defined shape morphing in hydrogel hybrids. First, we provide an overview of materials and methods that facilitate fabrication of such systems and outline the geometry and mechanics behind shape morphing of thin sheets. We then discuss how patterning of stiff inclusions within soft responsive hydrogels can be used to program both bending and swelling, thereby providing access to a wide array of complex 3D forms. The use of discretely patterned stiff regions to provide an effective composite response offers distinct advantages in terms of scalability and ease of fabrication compared with approaches based on smooth gradients within a single layer of responsive material. We discuss a number of recent advances wherein control of the mechanical properties and geometric characteristics of patterned stiff elements enables the formation of 3D shapes, including origami-inspired structures, concatenated helical frameworks, and surfaces with nonzero Gaussian curvature. Next, we outline how the inclusion of functional elements such as nanoparticles can enable unique pathways to programmable

  18. Active inflatable auxetic honeycomb structural concept for morphing wingtips

    International Nuclear Information System (INIS)

    Sun, Jian; Leng, Jinsong; Gao, Hongliang; Liu, Yanju; Scarpa, Fabrizio; Lira, Cristian

    2014-01-01

    This paper describes a new concept of an active honeycomb structure for morphing wingtip applications based on tubular inflatable systems and an auxetic cellular structure. A work-energy model to predict the output honeycomb displacement versus input pressure is developed together with a finite element formulation, and the results are compared with the data obtained from a small-scale example of an active honeycomb. An analysis of the hysteresis associated with multiple cyclic loading is also provided, and design considerations for a larger-scale wingtip demonstrator are made. (paper)

  19. MorphDB: Prioritizing Genes for Specialized Metabolism Pathways and Gene Ontology Categories in Plants

    Directory of Open Access Journals (Sweden)

    Arthur Zwaenepoel

    2018-03-01

    Full Text Available Recent times have seen an enormous growth of “omics” data, of which high-throughput gene expression data are arguably the most important from a functional perspective. Despite huge improvements in computational techniques for the functional classification of gene sequences, common similarity-based methods often fall short of providing full and reliable functional information. Recently, the combination of comparative genomics with approaches in functional genomics has received considerable interest for gene function analysis, leveraging both gene expression based guilt-by-association methods and annotation efforts in closely related model organisms. Besides the identification of missing genes in pathways, these methods also typically enable the discovery of biological regulators (i.e., transcription factors or signaling genes. A previously built guilt-by-association method is MORPH, which was proven to be an efficient algorithm that performs particularly well in identifying and prioritizing missing genes in plant metabolic pathways. Here, we present MorphDB, a resource where MORPH-based candidate genes for large-scale functional annotations (Gene Ontology, MapMan bins are integrated across multiple plant species. Besides a gene centric query utility, we present a comparative network approach that enables researchers to efficiently browse MORPH predictions across functional gene sets and species, facilitating efficient gene discovery and candidate gene prioritization. MorphDB is available at http://bioinformatics.psb.ugent.be/webtools/morphdb/morphDB/index/. We also provide a toolkit, named “MORPH bulk” (https://github.com/arzwa/morph-bulk, for running MORPH in bulk mode on novel data sets, enabling researchers to apply MORPH to their own species of interest.

  20. Mechanisms regulating caste differentiation in an aphid social system.

    Science.gov (United States)

    Shibao, Harunobu; Kutsukake, Mayako; Matsuyama, Shigeru; Fukatsu, Takema; Shimada, Masakazu

    2010-01-01

    For evolution and maintenance of the social systems of insect colonies, caste production should be controlled in response to external cues so that caste ratio in the colony is kept at an optimal range. Recent developments using artificial diet rearing techniques have revealed an underlying mechanism for adaptive control of caste production in a social aphid, Tuberaphis styraci, which has a sterile soldier caste in the 2(nd) instar. Aphid density was the proximate cue that acts on 1(st) instar nymphs and embryos to induce soldier differentiation. The final determination of soldier differentiation occurred postnatally, probably at a late 1(st) instar stage. Direct contact stimuli from live non-soldier aphids mediated the density effect. While coexisting non-soldiers facilitated soldier differentiation in 1(st) instar nymphs, coexisting soldiers acted to suppress such differentiation. These results suggest that caste production in aphid colonies is controlled by positive and negative feedback mechanisms consisting of density-dependent induction and suppression of soldier differentiation. Here, we demonstrate the mechanisms that coordinate aphid society, and provide a striking case of clonal superorganism system where simple responses of colony members to local extrinsic stimuli are integrated into a highly organized regulation of the whole colony.

  1. Predicting the occurrence of alate aphids in Brassicaceae

    Directory of Open Access Journals (Sweden)

    Francisco Jorge Cividanes

    2012-04-01

    Full Text Available The objective of this work was to predict the occurrence of alates of Brevicoryne brassicae, Lipaphis erysimi, and Myzus persicae (Hemiptera, Aphididae in Brassicaceae. The alate aphids were collected in yellow water traps from July 1997 to August 2005. Aphid population peaks were predicted using a degree‑day model. The meteorological factors, temperature, air relative humidity, rainfall, and sunshine hours, were used to provide precision indexes to evaluate the best predictor for the date of the first capture of alate aphids by the traps. The degree‑day model indicated that the peak population of the evaluated aphid species can be predicted using one of the following biofix dates: January 1st, June 1st, and the date of the first capture of the alate aphid species by the yellow water traps. The best predictor of B. brassicae occurrence is the number of days with minimum temperature >15°C, and of L. erysimi and M. persicae, the number of days with rainfall occurrence.

  2. Aphid sex pheromones: from discovery to commercial production.

    Science.gov (United States)

    Birkett, Michael A; Pickett, John A

    2003-03-01

    This review charts the progress made with aphid sex pheromone chemistry, from initial identification of cyclopentanoid nepetalactones, for example (4aS,7S,7aR)-nepetalactone (1). and (1R,4aS,7S,7aR)-nepetalactol (2). to commercial production from a renewable non-food crop, the catmint, Nepeta cataria (Lamiaceae). The availability of aphid sex pheromone components is now facilitating the development of new aphid pest control strategies, incorporating the use of other semiochemicals, particularly in the manipulation of populations of aphid parasitoids and aphid predators such as lacewings, which can utilise the nepetalactones and closely related molecules to locate their hosts and prey. This is the first example of a plant resource being developed as a feedstock for the production of a commercially valuable insect pheromone. The development of a plant-based production route highlights the tremendous potential that higher plants offer as cheap and renewable resources for the production of insect semiochemicals, through the wide array of secondary metabolites that they can generate.

  3. Low Aspect-Ratio Wings for Wing-Ships

    DEFF Research Database (Denmark)

    Filippone, Antonino; Selig, M.

    1998-01-01

    Flying on ground poses technical and aerodynamical challenges. The requirements for compactness, efficiency, manouverability, off-design operation,open new areas of investigations in the fieldof aerodynamic analysis and design. A review ofthe characteristics of low-aspect ratio wings, in- and out...... of ground, is presented. It is shownthat the performance of such wings is generally inferior to that of slender wings, although in ground placement can yield substantial improvements in the aerodynamic efficiency....

  4. Learning Visualizations by Analogy: Promoting Visual Literacy through Visualization Morphing.

    Science.gov (United States)

    Ruchikachorn, Puripant; Mueller, Klaus

    2015-09-01

    We propose the concept of teaching (and learning) unfamiliar visualizations by analogy, that is, demonstrating an unfamiliar visualization method by linking it to another more familiar one, where the in-betweens are designed to bridge the gap of these two visualizations and explain the difference in a gradual manner. As opposed to a textual description, our morphing explains an unfamiliar visualization through purely visual means. We demonstrate our idea by ways of four visualization pair examples: data table and parallel coordinates, scatterplot matrix and hyperbox, linear chart and spiral chart, and hierarchical pie chart and treemap. The analogy is commutative i.e. any member of the pair can be the unfamiliar visualization. A series of studies showed that this new paradigm can be an effective teaching tool. The participants could understand the unfamiliar visualization methods in all of the four pairs either fully or at least significantly better after they observed or interacted with the transitions from the familiar counterpart. The four examples suggest how helpful visualization pairings be identified and they will hopefully inspire other visualization morphings and associated transition strategies to be identified.

  5. Color and texture morphing with colloids on multilayered surfaces.

    Science.gov (United States)

    Chen, Ziguang; Li, Shumin; Arkebauer, Andrew; Gogos, George; Tan, Li

    2015-05-20

    Dynamic morphing of marine species to match with environment changes in color and texture is an advanced means for surviving, self-defense, and reproduction. Here we use colloids that are placed inside a multilayered structure to demonstrate color and texture morphing. The multilayer is composed of a thermal insulating base layer, a light absorbing mid layer, and a liquid top layer. When external light of moderate intensity (∼0.2 W cm(-2)) strikes the structure, colloids inside the liquid layer will be assembled to locations with an optimal absorption. When this system is exposed to continuous laser pulses, more than 18,000 times of reversible responses are recorded, where the system requests 20 ms to start the response and another 160 ms to complete. The flexibility of our concept further allows the system to be built on a variety of light-absorbing substrates, including dyed paper, gold thin film, and amorphous silicon, with the top layer even a solid.

  6. Design and simulation on the morphing composite propeller (Conference Presentation)

    Science.gov (United States)

    Chen, Fanlong; Li, Qinyu; Liu, Liwu; Lan, Xin; Liu, Yanju; Leng, Jinsong

    2017-04-01

    As one of the most crucial part of the unmanned underwater vehicle (UUV), the composite propeller plays an important role on the UUV's performance. As the composite propeller behaves excellent properties in hydroelastic facet and acoustic suppression, it attracts increasing attentions all over the globe. This paper goes a step further based on this idea, and comes up with a novel concept of "morphing composite propeller" (MCP) to improve the performance of the conventional composite propeller (CCP) to anticipate the improved propeller can perform better to propel the UUV. Based on the new concept, a novel MCP is designed. Each blade of the propeller is assembled with an active rotatable flap (ARF) to change the blade's local camber with flap rotation. Then the transmission mechanism (TM) has been designed and housed in the propeller blade to push the ARF. With the ARF rotating, the UUV can be propelled by different thrusts under certain rotation velocities of the propeller. Based on the design, the Fluent is exploited to analyze the fluid dynamics around the propeller. Finally, based on the design and hydrodynamic analysis, the structural response for the novel morphing composite propeller is calculated. The propeller blade is simplified and layered with composite materials. And the structure response of an MCP is obtained with various rotation angle under the hydrodynamic pressure. This simulation can instruct the design and fabrication techniques of the MCP.

  7. Aeroelastic performance evaluation of a flexure box morphing airfoil concept

    Science.gov (United States)

    Pankonien, Alexander M.; Inman, Daniel J.

    2014-04-01

    The flexure-box morphing aileron concept utilizes Macro-Fiber Composites (MFCs) and a compliant box to create a conformal morphing aileron. This work evaluates the impact of the number of MFCs on the performance, power and mass of the aileron by experimentally investigating two different actuator configurations: unimorph and bimorph. Implemented in a NACA 0012 airfoil with 304.8 mm chord, the unimorph and bimorph configurations are experimentally tested over a range of flow speeds from 5 to 20 m/s and angles of attack from -20 to 20 degrees under aerodynamic loads in a wind tunnel. An embedded flexible sensor is installed in the aileron to evaluate the effect of aerodynamic loading on tip position. For both design choices, the effect of actuation on lift, drag and pitching moment coefficients are measured. Finally, the impact on aileron mass and average power consumption due to the added MFCs is considered. The results showed the unimorph exhibiting superior ability to influence flow up to 15 m/s, with equivalent power consumption and lower overall mass. At 20 m/s, the bimorph exhibited superior control over aerodynamic forces and the unimorph experienced significant deformation due to aerodynamic loading.

  8. Morphing dynamics in light-triggered LC polymers (Conference Presentation)

    Science.gov (United States)

    Broer, Dirk J.

    2017-02-01

    Polymers that can change shape or surface topography in response to a trigger have a wide application potential varying from micro-robotics to avionics. Preferably this morphing proceeds fast and reversibly. We developed new morphing principles based on in-situ photopolymerized liquid crystal networks and on hybrid low molecular weight liquid crystals and liquid crystal networks. Commonly the triggers are temperature, light, pH or the presence of chemicals or other moisture. In the lecture we will focus on UV actuation and demonstrate that by accurate positioning of molecules over all three dimensions of a thin film or coating, the deformation figures can be pre-engineered. They can vary from simple gratings to very complex such as fingerprints that can be switched between off (flat surface) and on (corrugated surface) by light. The underlying principles are based on photo-induced changes in the degree of order of liquid crystal polymer networks and the accompanying changes in density by the formation of free volume. The surfaces can be switched with frequencies of the order of 0.1 Hz. In the lecture we will discuss several methods to fabricate the responsive layers as well as some of the most eye-catching properties. Also the mechanism of free volume generation will be addressed in terms of molecular dynamics and resonance.

  9. Virulent Diuraphis noxia Aphids Over-Express Calcium Signaling Proteins to Overcome Defenses of Aphid-Resistant Wheat Plants.

    Science.gov (United States)

    Sinha, Deepak K; Chandran, Predeesh; Timm, Alicia E; Aguirre-Rojas, Lina; Smith, C Michael

    2016-01-01

    The Russian wheat aphid, Diuraphis noxia, an invasive phytotoxic pest of wheat, Triticum aestivum, and barley, Hordeum vulgare, causes huge economic losses in Africa, South America, and North America. Most acceptable and ecologically beneficial aphid management strategies include selection and breeding of D. noxia-resistant varieties, and numerous D. noxia resistance genes have been identified in T. aestivum and H. vulgare. North American D. noxia biotype 1 is avirulent to T. aestivum varieties possessing Dn4 or Dn7 genes, while biotype 2 is virulent to Dn4 and avirulent to Dn7. The current investigation utilized next-generation RNAseq technology to reveal that biotype 2 over expresses proteins involved in calcium signaling, which activates phosphoinositide (PI) metabolism. Calcium signaling proteins comprised 36% of all transcripts identified in the two D. noxia biotypes. Depending on plant resistance gene-aphid biotype interaction, additional transcript groups included those involved in tissue growth; defense and stress response; zinc ion and related cofactor binding; and apoptosis. Activation of enzymes involved in PI metabolism by D. noxia biotype 2 aphids allows depletion of plant calcium that normally blocks aphid feeding sites in phloem sieve elements and enables successful, continuous feeding on plants resistant to avirulent biotype 1. Inhibition of the key enzyme phospholipase C significantly reduced biotype 2 salivation into phloem and phloem sap ingestion.

  10. Aphidophagous parasitoids can forage wheat crops before aphid infestation, Parana State, Brazil.

    Science.gov (United States)

    Ceolin Bortolotto, Orcial; de Oliveira Menezes Júnior, Ayres; Thibes Hoshino, Adriano

    2015-01-01

    Aphid parasitoids are common in Brazilian wheat fields, and parasitize aphids at the wheat tillering stage. However, there is little information available about when this natural enemy occurs in wheat crops. This study investigated the initial occurrence of aphid parasitoids in four commercial wheat crops in northern Paraná during the 2009 crop season. We installed two Malaise traps at each wheat farm, and 400 tillers were assessed weekly in each field for aphid abundance. During this study, we captured 4,355 aphid parasitoids and 197 aphids. Three species of braconid parasitoids were identified, including Aphidius colemani (Viereck 1912), Lysiphlebus testaceipes (Cresson 1880), and Diaeretiella rapae (McIntosh 1855). The aphids species identified were Rhopalosiphum padi (Linnaeus 1758) and Sitobion avenae (Fabricius 1775). This study showed that aphid parasitoids are present in wheat crops even when aphid densities are low, and in one farm, occurred before the aphids colonization. These reports can justified the high efficiency of these natural enemies against aphids in wheat fields. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

  11. Orally Delivered Scorpion Antimicrobial Peptides Exhibit Activity against Pea Aphid (Acyrthosiphon pisum and Its Bacterial Symbionts

    Directory of Open Access Journals (Sweden)

    Karen Luna-Ramirez

    2017-08-01

    Full Text Available Aphids are severe agricultural pests that damage crops by feeding on phloem sap and vectoring plant pathogens. Chemical insecticides provide an important aphid control strategy, but alternative and sustainable control measures are required to avoid rapidly emerging resistance, environmental contamination, and the risk to humans and beneficial organisms. Aphids are dependent on bacterial symbionts, which enable them to survive on phloem sap lacking essential nutrients, as well as conferring environmental stress tolerance and resistance to parasites. The evolution of aphids has been accompanied by the loss of many immunity-related genes, such as those encoding antibacterial peptides, which are prevalent in other insects, probably because any harm to the bacterial symbionts would inevitably affect the aphids themselves. This suggests that antimicrobial peptides (AMPs could replace or at least complement conventional insecticides for aphid control. We fed the pea aphids (Acyrthosiphon pisum with AMPs from the venom glands of scorpions. The AMPs reduced aphid survival, delayed their reproduction, displayed in vitro activity against aphid bacterial symbionts, and reduced the number of symbionts in vivo. Remarkably, we found that some of the scorpion AMPs compromised the aphid bacteriome, a specialized organ that harbours bacterial symbionts. Our data suggest that scorpion AMPs holds the potential to be developed as bio-insecticides, and are promising candidates for the engineering of aphid-resistant crops.

  12. Detecting aphid predation by earwigs in organic citrus orchards using molecular markers.

    Science.gov (United States)

    Romeu-Dalmau, C; Piñol, J; Agustí, N

    2012-10-01

    Aphids (Hemiptera: Aphidoidea) can damage citrus trees via direct damage to leaves and flowers or via the indirect transmission of viruses. Predators such as the European earwig, Forficula auricularia Linnaeus (Dermaptera: Forficulidae), may assist in keeping aphid populations under control in citrus orchards. Group-specific primers were developed to detect aphid DNA in earwigs, in order to determine earwig predation rates in aphids in Mediterranean organic citrus trees. These primers were designed in accordance with the alignment of comparable sequences of aphids and earwigs, and they amplified a 224 bp fragment of the mitochondrial cytochrome c oxidase subunit I (COI) region. Following the consumption of three to five Aphis spiraecola Patch, aphid DNA was still detectable in 50% of earwigs one day after the ingestion. When predation was evaluated in the field, aphid DNA was detected in earwigs in May, June and July but not in April and August. The most interesting result is that of May, when aphid abundance was very low but 30% of the earwigs tested positive for aphid DNA. This finding suggests that earwigs are important aphid predators in citrus orchards, as they probably alter aphid dynamics as a result of early seasonal pressure on this pest.

  13. Stem nematode counteracts plant resistance of aphids in alfalfa, Medicago sativa.

    Science.gov (United States)

    Ramirez, Ricardo A; Spears, Lori R

    2014-10-01

    Plants are exploited by a diverse community of insect herbivores and phytopathogens that interact indirectly through plant-mediated interactions. Generally, plants are thought to respond to insects and pathogens through different defensive signaling pathways. As plants are selected for resistance to one phytophagous organism type (insect vs. pathogen) in managed systems, it is not clear how this selection may affect community interactions. This study examined the effect of nematode-resistant varieties on aphid (Acyrthosiphon pisum) suppression, and then determined how infection by the stem nematode, Ditylenchus dipsaci, mediated ecological effects on aphids and on plant defense proteins. Four alfalfa (Medicago sativa) varieties were selected with resistance to nematodes only (+,-), aphids only (-,+), nematodes and aphids (+,+), and susceptibility to nematodes and aphids (-,-). Field and greenhouse experiments were conducted to isolate the effect of nematode infection and aphid abundance on each variety. We found that varieties resistant to nematode, regardless of aphid resistance, had the lowest aphid counts, suggesting possible cross-resistance. Aphid abundance, however, increased when plants were exposed to nematodes. Resistant varieties were associated with elevated saponins but these compounds were not affected by insect or pathogen feeding. Concentrations of peroxidases and trypsin inhibitors, however, were increased in nematode resistant varieties when exposed to nematodes and aphids, respectively. The patterns of plant defense were variable, and a combination of resistance traits and changes in nutrient availability may drive positive interactions between nematodes and aphids aboveground.

  14. Association of the Root Aphid Parasitoids Aclitus sappaphis and Paralipsis eikoae (Hymenoptera, Aphidiidae) with the Aphid-attending Ants Pheidole fervida and Lasius niger (Hymenoptera, Formicidae)

    OpenAIRE

    Hajimu, TAKADA; Yoshiaki, HASHIMOTO; Laboratory of Entomology, Faculty of Agriculture, Kyoto Prefectural University; Laboratory of Entomology, Faculty of Agriculture, Kyoto Prefectural University:(Present address)Graduate School of Science and Technology, Kobe University

    1985-01-01

    The association of two aphidiid parasitoids of a root aphid (Sappaphis piri MATSUMURA) on wormwood, Aclitus sappaphis TAKADA & SHIGA and Paralipsis eikoae (YASUMATSU), with two aphid-attending ants, Pheidole fervida FR. SMITH and Lasius niger (LINNE), was examined experimentally. The oviposition behavior of A. sappaphis was also observed. A single female parasitoid of each species was released on an aphid colony attended by workers (and soldiers) of either of the two ants, and her behavior an...

  15. Metabolomic profiling of the response of susceptible and resistant soybean strains to foxglove aphid, Aulacorthum solani Kaltenbach.

    Science.gov (United States)

    Sato, Dan; Akashi, Hiromichi; Sugimoto, Masahiro; Tomita, Masaru; Soga, Tomoyoshi

    2013-04-15

    Aphid infection reduces soybean (Glycine max [L.] Merr.) yield. Consequently, cultivation of aphid-resistant strains is a promising approach to pest control, and understanding the resistance mechanism is of importance. Here, we characterized the resistance of soybeans to foxglove aphid, Aulacorthum solani Kaltenbach, at the metabolite level. First, we evaluated aphid mortality and settlement rates on the leaves of two soybean strains, 'Tohoku149' and 'Suzuyutaka', and found that the former had strong resistance soon after introduction of the aphids. The metabolomic response to aphid introduction was analyzed using capillary electrophoresis-time-of-flight mass spectrometry. We found the following three features in the profiles: (1) concentrations of citrate, amino acids, and their intermediates were intrinsically higher for Tohoku149 than Suzuyutaka, (2) concentrations of several metabolites producing secondary metabolites, such as flavonoids and alkaloids, drastically changed 6h after aphid introduction, and (3) concentrations of TCA cycle metabolites increased in Tohoku149 48 h after aphid introduction. We also profiled free amino acids in aphids reared on both soybean strains and under starvation, and found that the profile of the aphids on Tohoku149 was similar to that of the starved aphids, but different to that of aphids on Suzuyutaka. These tests confirmed that aphids suck phloem sap even from Tohoku149. This study demonstrates the metabolomic profiles of both soybean strains and aphids, which will contribute to the molecular level understanding of mechanisms of soybean resistance to aphids. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Aphid infestation affecting the biogeochemistry of European beech saplings

    Science.gov (United States)

    Michalzik, B.; Levia, D. F., Jr.; Bischoff, S.; Näthe, K.

    2014-12-01

    Mass outbreaks of herbivore insects are known to perturb the functional properties of forests. However, it is less clear how endemic to moderate aboveground herbivory affects the vertical flow of nutrients from tree canopies to the soil. Here, we report on the effects of low to moderate infestation levels of the woolly beech aphid (Phyllaphis fagi L.) on the nutrient dynamics and hydrology of European beech (Fagus sylvatica L.). In a potted sapling experiment, we followed the vertical dynamics of nutrients via throughfall (TF), stemflow (SF) and litter leachates (LL) collected over ten weeks underneath infested and uninfested control trees. Aphid infestation amplifies the fluxes of K+, Mn2+ and particulate nitrogen (0.45μm aphid abundance by 26 and 16%, respectively. Differences in canopy-derived dissolved nitrogen and carbon compounds, sulfur (S), Ca2+, Mg2+, Na+ were aphid abundance on nutrient dynamics was most notable in TF and SF and diminished in LL.Aphid infestation greatly altered the SF fluxes of DOC, K+, Mn2+, DON and sulfur-species, which were significantly concentrated at the tree base by "funneling" the rainfall through the canopy biomass to the trunk. Normalized to one square meter, water and nutrient fluxes were amplified by a factor of up to 200 compared to TF.Imaging of leaf surfaces by scanning electron microscopy exhibited notable differences of the surface morphology and microbiology of control, lightly infested, and heavily infested leaves. This observation might point to an aphid-mediated alteration of the phyllosphere ecology triggering the microbial uptake of NH4-N and SO4-S and its transformation to particulate N by magnified biomass growth of the phyllosphere microflora, consequently changing the chemical partitioning and temporal availability of nitrogen.

  17. Selection of entomopathogenic fungi for aphid control.

    Science.gov (United States)

    Vu, Van Hanh; Hong, Suk Il; Kim, Keun

    2007-12-01

    Twelve strains of entomopathogenic fungi such as Lecanicillium lecanii, Paecilomyces farinosus, Beauveria bassiana, Metarhizium anisopliae, Cordyceps scarabaeicola, and Nomuraea rileyi were screened for aphid control. At 25 degrees C and 75% relative humidity (RH), among tested entomopathogenic fungi, L. lecanii 41185 showed the highest virulent pathogenicity for both Myzus persicae and Aphis gossypii, and their control values were both nearly 100% 5 and 2 d after treatment, respectively. Moreover, at an RH of 45% and in a wide temperature range (20-30 degrees C), L. lecanii 41185 also exhibited the highest virulence to M. persicae. The control value of M. persicae and the 50% lethal time (LT50) decreased significantly as the applied conidial concentration increased. The 50% lethal concentration (LC50) of the conidial suspension of this fungus was determined to be 6.55x10(5) conidia/ml. The control values of M. persicae resulting from the application of 1x10(7) and 1x10(8) conidia/ml were nearly the same and were significantly higher than that of 1x10(6) conidia/ml. The tested entomopathogenic fungi grew in a broad temperature range (15-30 degrees C). Lecanicillium strains showed optimum growth at 25 degrees C. The aerial conidia of Lecanicillium strains also could germinate in a broad temperature range (15-30 degrees C) and L. lecanii 41185 was the only strain with conidial germination at 35 degrees C.

  18. The NIa-Pro protein of Turnip mosaic virus improves growth and reproduction of the aphid vector, Myzus persicae (green peach aphid).

    Science.gov (United States)

    Casteel, Clare L; Yang, Chunling; Nanduri, Ananya C; De Jong, Hannah N; Whitham, Steven A; Jander, Georg

    2014-02-01

    Many plant viruses depend on aphids and other phloem-feeding insects for transmission within and among host plants. Thus, viruses may promote their own transmission by manipulating plant physiology to attract aphids and increase aphid reproduction. Consistent with this hypothesis, Myzus persicae (green peach aphids) prefer to settle on Nicotiana benthamiana infected with Turnip mosaic virus (TuMV) and fecundity on virus-infected N. benthamiana and Arabidopsis thaliana (Arabidopsis) is higher than on uninfected controls. TuMV infection suppresses callose deposition, an important plant defense, and increases the amount of free amino acids, the major source of nitrogen for aphids. To investigate the underlying molecular mechanisms of this phenomenon, 10 TuMV genes were over-expressed in plants to determine their effects on aphid reproduction. Production of a single TuMV protein, nuclear inclusion a-protease domain (NIa-Pro), increased M. persicae reproduction on both N. benthamiana and Arabidopsis. Similar to the effects that are observed during TuMV infection, NIa-Pro expression alone increased aphid arrestment, suppressed callose deposition and increased the abundance of free amino acids. Together, these results suggest a function for the TuMV NIa-Pro protein in manipulating the physiology of host plants. By attracting aphid vectors and promoting their reproduction, TuMV may influence plant-aphid interactions to promote its own transmission. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

  19. Spatial and Temporal Dynamics of Aphids (Hemiptera: Aphididae) in the Columbia Basin and Northeastern Oregon.

    Science.gov (United States)

    Klein, Mathew L; Rondon, Silvia I; Walenta, Darrin L; Zeb, Qamar; Murphy, Alexzandra F

    2017-08-01

    Aphid species, such as the potato aphid, Macrosiphum euphorbiae Thomas, and the green peach aphid, Myzus persicae Sulzer, are routinely considered the most important pests of potatoes. Potato aphid, green peach aphid, and more recently, other aphids such as the bird cherry-oat aphid Rhopalosiphum padi L. have been identified as vectors of multiple plant pathogenic viruses in potatoes. Since 2006, an area-wide trapping network consisting of ∼60 sites was developed through collaboration between researchers, extension faculty, and stakeholders, to monitor aphid populations in the Columbia Basin of Oregon (Umatilla and Morrow counties) and in northeastern Oregon (Union and Baker counties). Over a 9-yr period (2006 to 2014), aphid specimens were collected weekly using yellow bucket traps and specimens were then identified and counted to determine population levels during the growing season (May-September). Thus, aphid population data were compiled and subjected to spatial and temporal distribution analysis. Weather data, obtained from an established network of weather stations located in the monitoring areas, were used in a nonparametric multiplicative regression analysis to determine which abiotic variables may impact aphid populations. Weather conditions were characterized using confidence intervals (CIs) established based on weather data from 1999 to 2005 for each environmental variable. Aphid populations were found to have a heterogeneous distribution in most years; a few sites had high aphid populations while low numbers were observed at most sites; aphids were also found to correlate with several abiotic variables, namely, elevation, previous season temperature, and previous season dew point. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Persistence and transgenerational effect of plant-mediated RNAi in aphids.

    Science.gov (United States)

    Coleman, A D; Wouters, R H M; Mugford, S T; Hogenhout, S A

    2015-02-01

    Plant-mediated RNA interference (RNAi) has been successfully used as a tool to study gene function in aphids. The persistence and transgenerational effects of plant-mediated RNAi in the green peach aphid (GPA) Myzus persicae were investigated, with a focus on three genes with different functions in the aphid. Rack1 is a key component of various cellular processes inside aphids, while candidate effector genes MpC002 and MpPIntO2 (Mp2) modulate aphid-plant interactions. The gene sequences and functions did not affect RNAi-mediated down-regulation and persistence levels in the aphids. Maximal reduction of gene expression was ~70% and this was achieved at between 4 d and 8 d of exposure of the aphids to double-stranded RNA (dsRNA)-producing transgenic Arabidopsis thaliana. Moreover, gene expression levels returned to wild-type levels within ~6 d after removal of the aphids from the transgenic plants, indicating that a continuous supply of dsRNA is required to maintain the RNAi effect. Target genes were also down-regulated in nymphs born from mothers exposed to dsRNA-producing transgenic plants, and the RNAi effect lasted twice as long (12-14 d) in these nymphs. Investigations of the impact of RNAi over three generations of aphids revealed that aphids reared on dsMpC002 transgenic plants experienced a 60% decline in aphid reproduction levels compared with a 40% decline of aphids reared on dsRack1 and dsMpPIntO2 plants. In a field setting, a reduction of the aphid reproduction by 40-60% would dramatically decrease aphid population growth, contributing to a substantial reduction in agricultural losses. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  1. Orange oil effect in the control of fennel aphid

    OpenAIRE

    Ivanildo Cavalcanti de Albuquerque; Luciano de Medeiros Pereira Brito; Carlos Henrique de Brito; Edson Batista Lopes; Jacinto de Luna Batista

    2009-01-01

    In the properties where fennel is grown, in the states of Bahia, Sergipe, Pernambuco and Paraiba, at the Northeast of Brazil, a high rate of usage of pesticides in the crop, aiming to control the aphid Hyadaphis foeniculi. The purpose of this study was to evaluate the effect of orange oil Prev-Am (sodium tetraborohydrate decahydrate), in the control of H. foeniculi aphid of the fennel crop. The trial was conducted in a fennel field located in Lagoa Seca Experimental Station, belonging to the ...

  2. When the World Changes in Your Hands: Similarity Ratings of Objects Morphing during Active Exploration

    Directory of Open Access Journals (Sweden)

    Haemy Lee

    2012-10-01

    Full Text Available View-based theories of object recognition posit that coherent object representations are formed by linking together successive views of an actively explored object. This linking process relies on the assumption that the object does not change during exploration. Here, we test how object representations might be influenced when the shape of the object changes slowly during exploration. In our experiment, participants rated the similarity of two novel, 3D objects, whose shape was parametrically defined. Seventeen participants explored each object for 10 sec on an iPad which afforded natural and efficient interaction. The experiment contained a baseline condition, in which two objects of varying parameter-differences were presented, and a morphing condition, in which the first of the two objects slowly morphed during active exploration, making the objects more similar. Interestingly, no participant was aware of this morphing manipulation. Comparing baseline and morph trials, however, we found significantly higher similarity ratings during morphing [F(1,16 = 84.79, p < .001]. Furthermore, correlations between similarity ratings and differences in object parameters were high for the baseline condition (r = −.64, with smaller parameter differences being perceived as more similar. Interestingly, in the morphing condition correlations were lower for parameter differences after the morph (r = −.22, but remained high for differences before (r = −.47 and during morphing (r = −.50. In conclusion, similarity ratings in the baseline condition captured the complex parameter space well. Although participants did not notice the changing shape, morphing did systematically bias the ratings. Interestingly, similarity judgments correlated better in the initial exploration phase, suggesting a capacity limit for view integration of complex shapes.

  3. Differential gene expression during early development in recently evolved and sympatric Arctic charr morphs

    Directory of Open Access Journals (Sweden)

    Jóhannes Guðbrandsson

    2018-02-01

    Full Text Available Phenotypic differences between closely related taxa or populations can arise through genetic variation or be environmentally induced, leading to altered transcription of genes during development. Comparative developmental studies of closely related species or variable populations within species can help to elucidate the molecular mechanisms related to evolutionary divergence and speciation. Studies of Arctic charr (Salvelinus alpinus and related salmonids have revealed considerable phenotypic variation among populations and in Arctic charr many cases of extensive variation within lakes (resource polymorphism have been recorded. One example is the four Arctic charr morphs in the ∼10,000 year old Lake Thingvallavatn, which differ in numerous morphological and life history traits. We set out to investigate the molecular and developmental roots of this polymorphism by studying gene expression in embryos of three of the morphs reared in a common garden set-up. We performed RNA-sequencing, de-novo transcriptome assembly and compared gene expression among morphs during an important timeframe in early development, i.e., preceding the formation of key trophic structures. Expectedly, developmental time was the predominant explanatory variable. As the data were affected by some form of RNA-degradation even though all samples passed quality control testing, an estimate of 3′-bias was the second most common explanatory variable. Importantly, morph, both as an independent variable and as interaction with developmental time, affected the expression of numerous transcripts. Transcripts with morph effect, separated the three morphs at the expression level, with the two benthic morphs being more similar. However, Gene Ontology analyses did not reveal clear functional enrichment of transcripts between groups. Verification via qPCR confirmed differential expression of several genes between the morphs, including regulatory genes such as AT-Rich Interaction

  4. Mesh-morphing algorithms for specimen-specific finite element modeling.

    Science.gov (United States)

    Sigal, Ian A; Hardisty, Michael R; Whyne, Cari M

    2008-01-01

    Despite recent advances in software for meshing specimen-specific geometries, considerable effort is still often required to produce and analyze specimen-specific models suitable for biomechanical analysis through finite element modeling. We hypothesize that it is possible to obtain accurate models by adapting a pre-existing geometry to represent a target specimen using morphing techniques. Here we present two algorithms for morphing, automated wrapping (AW) and manual landmarks (ML), and demonstrate their use to prepare specimen-specific models of caudal rat vertebrae. We evaluate the algorithms by measuring the distance between target and morphed geometries and by comparing response to axial loading simulated with finite element (FE) methods. First a traditional reconstruction process based on microCT was used to obtain two natural specimen-specific FE models. Next, the two morphing algorithms were used to compute mappings from the surface of one model, the source, to the other, the target, and to use this mapping to morph the source mesh to produce a target mesh. The microCT images were then used to assign element-specific material properties. In AW the mappings were obtained by wrapping the source and target surfaces with an auxiliary triangulated surface. In ML, landmarks were manually placed on corresponding locations on the surfaces of both source and target. Both morphing algorithms were successful in reproducing the shape of the target vertebra with a median distance between natural and morphed models of 18.8 and 32.2 microm, respectively, for AW and ML. Whereas AW-morphing produced a surface more closely resembling that of the target, ML guaranteed correspondence of the landmark locations between source and target. Morphing preserved the quality of the mesh producing models suitable for FE simulation. Moreover, there were only minor differences between natural and morphed models in predictions of deformation, strain and stress. We therefore conclude that

  5. NUMERICAL INVESTIGATION OF TWO ELEMENT CAMBER MORPHING AIRFOIL IN LOW REYNOLDS NUMBER FLOWS

    OpenAIRE

    RAJESH SENTHIL KUMAR T.; V. SIVAKUMAR; BALAJEE RAMAKRISHNANANDA; ARJHUN A.K, SURIYAPANDIYAN

    2017-01-01

    Aerodynamic performance of a two-element camber morphing airfoil was investigated at low Reynolds number using the transient SST model in ANSYS FLUENT 14.0 and eN method in XFLR5. The two-element camber morphing concept was employed to morph the baseline airfoil into another airfoil by altering the orientation of mean-line at 35% of the chord to achieve better aerodynamic efficiency. NACA 0012 was selected as baseline airfoil. NACA 23012 was chosen as the test case as it has the camber-line s...

  6. Long-term phenological trends, species accumulation rates, aphid traits and climate: five decades of change in migrating aphids.

    Science.gov (United States)

    Bell, James R; Alderson, Lynda; Izera, Daniela; Kruger, Tracey; Parker, Sue; Pickup, Jon; Shortall, Chris R; Taylor, Mark S; Verrier, Paul; Harrington, Richard

    2015-01-01

    Aphids represent a significant challenge to food production. The Rothamsted Insect Survey (RIS) runs a network of 12·2-m suction-traps throughout the year to collect migrating aphids. In 2014, the RIS celebrated its 50th anniversary. This paper marks that achievement with an extensive spatiotemporal analysis and the provision of the first British annotated checklist of aphids since 1964. Our main aim was to elucidate mechanisms that advance aphid phenology under climate change and explain these using life-history traits. We then highlight emerging pests using accumulation patterns. Linear and nonlinear mixed-effect models estimated the average rate of change per annum and effects of climate on annual counts, first and last flights and length of flight season since 1965. Two climate drivers were used: the accumulated day degrees above 16 °C (ADD16) indicated the potential for migration during the aphid season; the North Atlantic Oscillation (NAO) signalled the severity of the winter before migration took place. All 55 species studied had earlier first flight trends at rate of β = -0·611 ± SE 0·015 days year(-1). Of these species, 49% had earlier last flights, but the average species effect appeared relatively stationary (β = -0·010 ± SE 0·022 days year(-1)). Most species (85%) showed increasing duration of their flight season (β = 0·336 ± SE 0·026 days year(-1)), even though only 54% increased their log annual count (β = 0·002 ± SE aphid phenology in a spatiotemporal context. Early in the year when the first aphids were migrating, the effect of the winter NAO was highly significant. Further into the year, ADD16 was a strong predictor. Latitude had a near linear effect on first flights, whereas longitude produced a generally less-clear effect on all responses. Aphids that are anholocyclic (permanently parthenogenetic) or are monoecious (non-host-alternating) were advancing their phenology faster than those that were not

  7. Aeroelastic Wing Shaping Using Distributed Propulsion

    Science.gov (United States)

    Nguyen, Nhan T. (Inventor); Reynolds, Kevin Wayne (Inventor); Ting, Eric B. (Inventor)

    2017-01-01

    An aircraft has wings configured to twist during flight. Inboard and outboard propulsion devices, such as turbofans or other propulsors, are connected to each wing, and are spaced along the wing span. A flight controller independently controls thrust of the inboard and outboard propulsion devices to significantly change flight dynamics, including changing thrust of outboard propulsion devices to twist the wing, and to differentially apply thrust on each wing to change yaw and other aspects of the aircraft during various stages of a flight mission. One or more generators can be positioned upon the wing to provide power for propulsion devices on the same wing, and on an opposite wing.

  8. Butterflies regulate wing temperatures using radiative cooling

    Science.gov (United States)

    Tsai, Cheng-Chia; Shi, Norman Nan; Ren, Crystal; Pelaez, Julianne; Bernard, Gary D.; Yu, Nanfang; Pierce, Naomi

    2017-09-01

    Butterfly wings are live organs embedded with multiple sensory neurons and, in some species, with pheromoneproducing cells. The proper function of butterfly wings demands a suitable temperature range, but the wings can overheat quickly in the sun due to their small thermal capacity. We developed an infrared technique to map butterfly wing temperatures and discovered that despite the wings' diverse visible colors, regions of wings that contain live cells are the coolest, resulting from the thickness of the wings and scale nanostructures. We also demonstrated that butterflies use behavioral traits to prevent overheating of their wings.

  9. First report of Pandora neoaphidis resting spore formation in vivo in aphid hosts

    DEFF Research Database (Denmark)

    Clara Scorsetti, Ana; Jensen, Annette Bruun; Lopez Lastra, Claudia

    2012-01-01

    The entomopathogenic fungus Pandora neoaphidis is a recognized pathogen of aphids, causes natural epizootics in aphid populations, and interacts and competes with aphid predators and parasitoids. Survival of entomophthoralean fungi in periods of unsuitable weather conditions or lack of appropriat...

  10. Stiffness of desiccating insect wings

    Energy Technology Data Exchange (ETDEWEB)

    Mengesha, T E; Vallance, R R [Department of Mechanical Engineering, The George Washington University, 738 Phillips Hall, 801 22nd St NW, Washington, DC 20052 (United States); Mittal, R, E-mail: vallance@gwu.edu [Department of Mechanical Engineering, Johns Hopkins University, 126 Latrobe Hall, 3400 N Charles Street, Baltimore, MD 21218 (United States)

    2011-03-15

    The stiffness of insect wings is typically determined through experimental measurements. Such experiments are performed on wings removed from insects. However, the wings are subject to desiccation which typically leads to an increase in their stiffness. Although this effect of desiccation is well known, a comprehensive study of the rate of change in stiffness of desiccating insect wings would be a significant aid in planning experiments as well as interpreting data from such experiments. This communication presents a comprehensive experimental analysis of the change in mass and stiffness of gradually desiccating forewings of Painted Lady butterflies (Vanessa cardui). Mass and stiffness of the forewings of five butterflies were simultaneously measured every 10 min over a 24 h period. The averaged results show that wing mass declined exponentially by 21.1% over this time period with a time constant of 9.8 h, while wing stiffness increased linearly by 46.2% at a rate of 23.4 {mu}N mm{sup -1} h{sup -1}. For the forewings of a single butterfly, the experiment was performed over a period of 1 week, and the results show that wing mass declined exponentially by 52.2% with a time constant of 30.2 h until it reached a steady-state level of 2.00 mg, while wing stiffness increased exponentially by 90.7% until it reached a steady-state level of 1.70 mN mm{sup -1}. (communication)

  11. Inventory and assessment of foliar natural enemies of the soybean aphid (Hemiptera: Aphididae) in South Dakota.

    Science.gov (United States)

    Hesler, Louis S

    2014-06-01

    Soybean aphid (Aphis glycines Matsumura) (Hemiptera: Aphididae) is a major pest of soybean in northern production regions of North America, and insecticides have been the primary management approach while alternative methods are developed. Knowledge of arthropod natural enemies and their impact on soybean aphid is critical for developing biological control as a management tool. Soybean is a major field crop in South Dakota, but information about its natural enemies and their impact on soybean aphid is lacking. Thus, this study was conducted in field plots in eastern South Dakota during July and August of 2004 and 2005 to characterize foliar-dwelling, arthropod natural enemies of soybean aphid, and it used exclusion techniques to determine impact of natural enemies and ants (Hymenoptera: Formicidae) on soybean aphid densities. In open field plots, weekly soybean aphid densities reached a plateau of several hundred aphids per plant in 2004, and peaked at roughly 400 aphids per plant in 2005. Despite these densities, a relatively high frequency of aphid-infested plants lacked arthropod natural enemies. Lady beetles (Coleoptera: Coccinellidae) were most abundant, peaking at 90 and 52% of all natural enemies sampled in respective years, and Harmonia axyridis Pallas was the most abundant lady beetle. Green lacewings (Neuroptera: Chrysopidae) were abundant in 2005, due mainly to large numbers of their eggs. Abundances of arachnids and coccinellid larvae correlated with soybean aphid densities each year, and chrysopid egg abundance was correlated with aphid density in 2005. Three-week cage treatments of artificially infested soybean plants in 2004 showed that noncaged plants had fewer soybean aphids than caged plants, but abundance of soybean aphid did not differ among open cages and ones that provided partial or total exclusion of natural enemies. In 2005, plants within open cages had fewer soybean aphids than those within cages that excluded natural enemies, and aphid

  12. Dropping Behavior in the Pea Aphid (Hemiptera: Aphididae): How Does Environmental Context Affect Antipredator Responses?

    Science.gov (United States)

    Harrison, Katharine V; Preisser, Evan L

    2016-01-01

    The pea aphid Acyrthosiphon pisum : Harris (Hemiptera: Aphididae) is a phloem-feeding insect whose antipredator defenses include kicking, walking away, and dropping from the plant. Aphid dropping, a risky and energetically costly antipredator behavior, can be increased by the release of aphid alarm pheromone; there is also evidence that insect density and plant health can affect the likelihood of aphids engaging in this behavior. We investigated whether interactions between alarm cues, insect density, and plant health can alter the dropping behavior of aphids in response to an artificial disturbance. The presence of the alarm pheromone E-β-farnesene resulted in a nearly 15-fold increase in aphid dropping behavior; the other two factors, however, did not affect dropping and none of the two- or three-way interactions were significant. This was surprising because aphids affected plant health: production of new plant biomass after 5 d of exposure to high aphid densities was 50% lower than in the control treatment. This research adds to our understanding of the factors affecting aphid antipredator behavior; the fact that neither aphid density nor feeding period impacted dropping may reflect the high energetic costs of this activity and an unwillingness to use it in any but the riskiest situations. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America.

  13. Parasitoid- and hyperparasitoid-mediated seasonal dynamics of the cabbage aphid (Hemiptera: Aphididae).

    Science.gov (United States)

    Nematollahi, Mohammad Reza; Fathipour, Yaghoub; Talebi, Ali Asghar; Karimzadeh, Javad; Zalucki, Myron Philip

    2014-12-01

    The population dynamics of the cabbage aphid, Brevicoryne brassicae (L.), its parasitoid, Diaeretiella rapae McIntosh, and hyperparasitoids, Pachyneuron spp., were quantified under field conditions during 2011-2013, by examining synchronization, parasitoid: aphid ratio, possible effect of density on the finite rate of increase, and spatial coincidence. The rates of parasitism and hyperparasitism were based on rearing field-collected mummies and live parasitized aphids, and density of the aphid were estimated using heat extraction and subsampling techniques. Only one parasitoid, D. rapae (80% on average), and two hyperparasitoid species from the genus of Pachyneuron (6.5% on average), namely Pachyneuron aphidis (Bouché) and Pachyneuron groenlandicum (Holmgren), were reared from the aphid mummies. Significant Pearson's time lagged correlations for percentage parasitism versus aphid density and for percentage hyperparasitism versus mummy density indicated that 2-3 wk is needed for D. rapae and Pachyneuron spp. to show impact on their respective host's population. In early spring, the parasitoid: aphid ratio was low (0.11 on average) while aphid density was increasing. Based on Taylor's power law, D. rapae and Pachyneuron spp., as well as B. brassicae, had an aggregated distribution among canola plants. Moreover, a high degree of spatial overlap was found between D. rapae and B. brassicae and between Pachyneuron spp. and D. rapae. In general, the parasitoid had good spatial coincidence with its aphid host but because of a lack of parasitoid-host synchronization and low parasitoid: aphid ratio, impact on the host population was low.

  14. High susceptibility of Bt maize to aphids enhances the performance of parasitoids of lepidopteran pests.

    Directory of Open Access Journals (Sweden)

    Cristina A Faria

    Full Text Available Concerns about possible undesired environmental effects of transgenic crops have prompted numerous evaluations of such crops. So-called Bt crops receive particular attention because they carry bacteria-derived genes coding for insecticidal proteins that might negatively affect non-target arthropods. Here we show a remarkable positive effect of Bt maize on the performance of the corn leaf aphid Rhopalosiphum maidis, which in turn enhanced the performance of parasitic wasps that feed on aphid honeydew. Within five out of six pairs that were evaluated, transgenic maize lines were significantly more susceptible to aphids than their near-isogenic equivalents, with the remaining pair being equally susceptible. The aphids feed from the phloem sieve element content and analyses of this sap in selected maize lines revealed marginally, but significantly higher amino acid levels in Bt maize, which might partially explain the observed increased aphid performance. Larger colony densities of aphids on Bt plants resulted in an increased production of honeydew that can be used as food by beneficial insects. Indeed, Cotesia marginiventris, a parasitoid of lepidopteran pests, lived longer and parasitized more pest caterpillars in the presence of aphid-infested Bt maize than in the presence of aphid-infested isogenic maize. Hence, depending on aphid pest thresholds, the observed increased susceptibility of Bt maize to aphids may be either a welcome or an undesirable side effect.

  15. The effect of predators and hymenopterous parasites on population fluctuations of alfalfa aphids.

    Science.gov (United States)

    Rassoulian, Gh Reza

    2005-01-01

    Among alfalfa pests in Iran three aphid species, green alfalfa aphid Acyrthosiphon pisum Harris spotted alfalfa aphid Therioaphis trifolii forma maculata Buckton and blue alfalfa aphid, Acyrthosiphon kondoi Shinji are important pests. The green alfalfa aphid can be observed all along the growing season particularly from late May to mid June at Karaj climate conditions. During this period, the mean monthly maximum temperature and relative humidity were about 28 degrees C and 60-65% respectively. This aphid overwinters as nymph and viviparous female. Sexual forms and eggs could not be seen under field conditions. Spotted alfalfa aphid, Therioaphis trifolii fonna maculata is the most prevalent aphid in summer time, when the mean monthly maximum temperature and relative humidity are about 33-34 degrees C and 44-58% respectively. Sexual individuals have been observed in the laboratory but not in the field. Among predators (Coccinella septempunctata, Adonia variegata, Syrphus cinctus, S. corolae, S. grassulariae, Chrysoperla carnea and Nabis capsiformis) one coccinellid species, C. septempunctata, had greatest impact on fluctuations of population. Among hymenopterous parasitoids two species have been collected from alfalfa field they were Aphidius ervi and Praon palitans. These parasitoids destroyed a good percent of aphids and statistically proved to lower aphid populations significantly.

  16. AERODYNAMICS OF WING TIP SAILS

    Directory of Open Access Journals (Sweden)

    MUSHTAK AL-ATABI

    2006-06-01

    Full Text Available Observers have always been fascinated by soaring birds. An interesting feature of these birds is the existence of few feathers extending from the tip of the wing. In this paper, small lifting surfaces were fitted to the tip of a NACA0012 wing in a fashion similar to that of wing tip feathers. Experimental measurements of induced drag, longitudinal static stability and trailing vortex structure were obtained.The tests showed that adding wing tip surfaces (sails decreased the induced drag factor and increased the longitudinal static stability. Results identified two discrete appositely rotated tip vortices and showed the ability of wing tip surfaces to break them down and to diffuse them.

  17. An advanced kinetic theory for morphing continuum with inner structures

    Science.gov (United States)

    Chen, James

    2017-12-01

    Advanced kinetic theory with the Boltzmann-Curtiss equation provides a promising tool for polyatomic gas flows, especially for fluid flows containing inner structures, such as turbulence, polyatomic gas flows and others. Although a Hamiltonian-based distribution function was proposed for diatomic gas flow, a general distribution function for the generalized Boltzmann-Curtiss equations and polyatomic gas flow is still out of reach. With assistance from Boltzmann's entropy principle, a generalized Boltzmann-Curtiss distribution for polyatomic gas flow is introduced. The corresponding governing equations at equilibrium state are derived and compared with Eringen's morphing (micropolar) continuum theory derived under the framework of rational continuum thermomechanics. Although rational continuum thermomechanics has the advantages of mathematical rigor and simplicity, the presented statistical kinetic theory approach provides a clear physical picture for what the governing equations represent.

  18. Noise-assisted morphing of memory and logic function

    International Nuclear Information System (INIS)

    Kohar, Vivek; Sinha, Sudeshna

    2012-01-01

    We demonstrate how noise allows a bistable system to behave as a memory device, as well as a logic gate. Namely, in some optimal range of noise, the system can operate flexibly, both as a NAND/AND gate and a Set–Reset latch, by varying an asymmetrizing bias. Thus we show how this system implements memory, even for sub-threshold input signals, using noise constructively to store information. This can lead to the development of reconfigurable devices, that can switch efficiently between memory tasks and logic operations. -- Highlights: ► We consider a nonlinear system in a noisy environment. ► We show that the system can function as a robust memory element. ► Further, the response of the system can be easily morphed from memory to logic operations. ► Such systems can potentially act as building blocks of “smart” computing devices.

  19. Morphing hydrogel patterns by thermo-reversible fluorescence switching.

    Science.gov (United States)

    Bat, Erhan; Lin, En-Wei; Saxer, Sina; Maynard, Heather D

    2014-07-01

    Stimuli responsive surfaces that show reversible fluorescence switching behavior in response to temperature changes were fabricated. Oligo(ethylene glycol) methacrylate thermoresponsive polymers with amine end-groups were prepared by atom transfer radical polymerization (ATRP). The polymers were patterned on silicon surfaces by electron beam (e-beam) lithography, followed by conjugation of self-quenching fluorophores. Fluorophore conjugated hydrogel thin films were bright when the gels were swollen; upon temperature-induced collapse of the gels, self-quenching of the fluorophores led to significant attenuation of fluorescence. Importantly, the fluorescence was regained when the temperature was cooled. The fluorescence switching behavior of the hydrogels for up to ten cycles was investigated and the swelling-collapse was verified by atomic force microscopy. Morphing surfaces that change shape several times upon increase in temperature were obtained by patterning multiple stimuli responsive polymers. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Morphing structures using soft polymers for active deployment

    International Nuclear Information System (INIS)

    Daynes, Stephen; Grisdale, Amy; Trask, Richard; Seddon, Annela

    2014-01-01

    In this study, we take inspiration from morphing strategies observed in nature, origami design and stiffness tailoring principles in engineering, to develop a thin walled, low cost, bistable cell geometry capable of reversibly unfolding from a flat configuration to a highly textured configuration. Finite element analysis was used to model the cell deployment and capture the experimentally observed bistability of the reinforced silicone elastomer. Through the combination of flexible elastomers with locally reinforced regions enables a highly tailorable and controllable deployment response. These cells are bistable allowing them to maintain their shape when either deployed or retracted without sustained actuation. It is proposed that such deployable cells with reversible surfaces and texture change can be used as a means of adaptive camouflage. (fast track communication)

  1. Chemical Morphing of DNA Containing Four Noncanonical Bases.

    Science.gov (United States)

    Eremeeva, Elena; Abramov, Michail; Margamuljana, Lia; Rozenski, Jef; Pezo, Valerie; Marlière, Philippe; Herdewijn, Piet

    2016-06-20

    The ability of alternative nucleic acids, in which all four nucleobases are substituted, to replicate in vitro and to serve as genetic templates in vivo was evaluated. A nucleotide triphosphate set of 5-chloro-2'-deoxyuridine, 7-deaza-2'-deoxyadenosine, 5-fluoro-2'-deoxycytidine, and 7-deaza-2'deoxyguanosine successfully underwent polymerase chain reaction (PCR) amplification using templates of different lengths (57 or 525mer) and Taq or Vent (exo-) DNA polymerases as catalysts. Furthermore, a fully morphed gene encoding a dihydrofolate reductase was generated by PCR using these fully substituted nucleotides and was shown to transform and confer trimethoprim resistance to E. coli. These results demonstrated that fully modified templates were accurately read by the bacterial replication machinery and provide the first example of a long fully modified DNA molecule being functional in vivo. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Signal Morphing techniques and possible application to Higgs properties measurements

    CERN Document Server

    Ecker, Katharina Maria; The ATLAS collaboration

    2016-01-01

    One way of describing deviations from the Standard Model is via Effective Field Theories or pseudo-observables, where higher order operators modify the couplings and the kinematics of the interaction of the Standard Model particles. Generating Monte Carlo events for every testable set of parameters for such a theory would require computing resources beyond the ones currently available in ATLAS. Up to now, Matrix-Element based reweighting techniques have been often used to model Beyond Standard Model process starting from Standard Model simulated events. In this talk, we review the advantages and the limitations of morphing techniques to construct continuous probability model for signal parameters, interpolating between a finite number of distributions obtained from the simulation chain. The technique will be exemplified by searching for deviations from the Standard Model predictions in Higgs properties measurements.

  3. Modeling bistable behaviors in morphing structures through finite element simulations.

    Science.gov (United States)

    Guo, Qiaohang; Zheng, Huang; Chen, Wenzhe; Chen, Zi

    2014-01-01

    Bistable structures, exemplified by the Venus flytrap and slap bracelets, can transit between different configurations upon certain external stimulation. Here we study, through three-dimensional finite element simulations, the bistable behaviors in elastic plates in the absence of terminate loads, but with pre-strains in one (or both) of the two composite layers. Both the scenarios with and without a given geometric mis-orientation angle are investigated, the results of which are consistent with recent theoretical and experimental studies. This work can open ample venues for programmable designs of plant/shell structures with large deformations, with applications in designing bio-inspired robotics for biomedical research and morphing/deployable structures in aerospace engineering.

  4. Contact-aided compliant mechanisms for morphing aircraft skin

    Science.gov (United States)

    Mehta, Vipul; Frecker, Mary; Lesieutre, George

    2008-03-01

    Sandwich structures consisting of contact-aided compliant mechanisms are presented for morphing aircraft skin. A contact mechanism is used to alleviate stresses and to decrease the out-of-plane deflection. A methodology to design such mechanisms, which takes into account the aerodynamic loads, is presented. The method is applied to a small UAV and results are compared with those of honeycomb structures in terms of structural mass, global strain and maximum stresses. Different material models such as linearly elastic and multi-linear elastic are considered. For linearly elastic materials, contact-induced stress-relief is advantageous and for nonlinear elastic materials, reduction of transverse deflection due to contact is useful. In either case, the structural mass of the contact-aided structures is less than that of the corresponding non-contact structures.

  5. Host Plants Indirectly Influence Plant Virus Transmission by Altering Gut Cysteine Protease Activity of Aphid Vectors.

    Science.gov (United States)

    Pinheiro, Patricia V; Ghanim, Murad; Alexander, Mariko; Rebelo, Ana Rita; Santos, Rogerio S; Orsburn, Benjamin C; Gray, Stewart; Cilia, Michelle

    2017-04-01

    The green peach aphid, Myzus persicae , is a vector of the Potato leafroll virus (PLRV, Luteoviridae), transmitted exclusively by aphids in a circulative manner. PLRV transmission efficiency was significantly reduced when a clonal lineage of M. persicae was reared on turnip as compared with the weed physalis, and this was a transient effect caused by a host-switch response. A trend of higher PLRV titer in physalis-reared aphids as compared with turnip-reared aphids was observed at 24 h and 72 h after virus acquisition. The major difference in the proteomes of these aphids was the up-regulation of predicted lysosomal enzymes, in particular the cysteine protease cathepsin B (cathB), in aphids reared on turnip. The aphid midgut is the site of PLRV acquisition, and cathB and PLRV localization were starkly different in midguts of the aphids reared on the two host plants. In viruliferous aphids that were reared on turnip, there was near complete colocalization of cathB and PLRV at the cell membranes, which was not observed in physalis-reared aphids. Chemical inhibition of cathB restored the ability of aphids reared on turnip to transmit PLRV in a dose-dependent manner, showing that the increased activity of cathB and other cysteine proteases at the cell membrane indirectly decreased virus transmission by aphids. Understanding how the host plant influences virus transmission by aphids is critical for growers to manage the spread of virus among field crops. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  6. Effects of thiamethoxam seed treatments on soybean aphid (Hemiptera: Aphididae) feeding behavior.

    Science.gov (United States)

    Stamm, M D; Heng-Moss, T M; Baxendale, F P; Reese, J C; Siegfried, B D; Hunt, T E; Gaussoin, R E; Blankenship, E E

    2013-12-01

    Since its discovery in North America in 2000, the soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), has rapidly become an important pest of soybean [Glycine max (L.) Merrill], sometimes resulting in significant yield losses. Previous research has documented the toxicity of neonicotinoid seed treatments to soybean aphids, but control under field conditions has been inconsistent. Imidacloprid, a popular neonicotinoid insecticide, has been shown to exhibit antifeedant effects on aphids. Antifeedant activity has not been demonstrated for other neonicotinoids, including thiamethoxam. This research investigated the effects of a thiamethoxam seed treatment on soybean aphid feeding behavior by using electronic penetration graphs (EPG) to visualize stylet penetration behavior. Soybean aphid feeding behavior was assessed for 9 h on thiamethoxam-treated and untreated soybeans (V2 and V4 stages). Because results were inconclusive from initial experiments, a study was conducted to document the effects of thiamethoxam-treated soybeans on soybean aphid survival. The seed treatment was shown to negatively affect aphid survival at 4, 8, and 11 d after aphid introduction. A subsequent EPG study then was designed to document soybean aphid feeding behavior for 15 h, after an initial exposure of 9 h to thiamethoxam-treated soybeans. In this study, the exposed aphids exhibited significant differences in feeding behavior compared with those aphids feeding on untreated soybeans. Soybean aphids on thiamethoxam-treated soybeans spent significantly less time feeding in the sieve element phase, with a greater duration of nonprobing events. These studies suggest soybean aphids are unable to ingest phloem sap, which may be another important element in seed treatment protection.

  7. Ants Learn Aphid Species as Mutualistic Partners: Is the Learning Behavior Species-Specific?

    Science.gov (United States)

    Hayashi, Masayuki; Nakamuta, Kiyoshi; Nomura, Masashi

    2015-12-01

    In ant-aphid associations, many aphid species provide ants with honeydew and are tended by ants, whereas others are never tended and are frequently preyed upon by ants. In these relationships, ants must have the ability to discriminate among aphid species, with mutualistic aphids being accepted as partners rather than prey. Although ants reportedly use cuticular hydrocarbons (CHCs) of aphids to differentiate between mutualistic and non-mutualistic species, it is unclear whether the ability to recognize mutualistic aphid species as partners is innate or involves learning. Therefore, we tested whether aphid recognition by ants depends on learning, and whether the learning behavior is species-specific. When workers of the ant Tetramorium tsushimae had previously tended the cowpea aphid, Aphis craccivora, they were less aggressive toward this species. In addition, ants also reduced their aggressiveness toward another mutualistic aphid species, Aphis fabae, after tending A. craccivora, whereas ants remained aggressive toward the non-mutualistic aphid, Acyrthosiphon pisum, regardless of whether or not they had previous experience in tending A. craccivora. When ants were offered glass dummies treated with CHCs of these aphid species, ants that had tended A. craccivora displayed reduced aggression toward CHCs of A. craccivora and A. fabae. Chemical analyses showed the similarity of the CHC profiles between A. craccivora and A. fabae but not with A. pisum. These results suggest that aphid recognition of ants involves learning, and that the learning behavior may not be species-specific because of the similarity of CHCs between different aphid species with which they form mutualisms.

  8. Ecological specialization in Diaeretiella rapae (Hymenoptera: Braconidae: Aphidiinae) on aphid species from wild and cultivated plants.

    Science.gov (United States)

    Navasse, Y; Derocles, S A P; Plantegenest, M; Le Ralec, A

    2018-04-01

    Diaeretiella rapae is an aphid parasitoid with potential for use in biological control strategies. However, several recent genetic studies have challenged the long held view that it is a generalist parasitoid. We investigated its ecological specialization and ability to use resources in cultivated and uncultivated areas. Ecological specialization would reduce its ability to exploit the diversity of aphid species, particularly in uncultivated areas, and to control pest aphids. Four D. rapae strains were studied, three reared on pest aphids on Brassicaceae and one strain on a non-pest aphid on Chenopodiaceae. For each strain, we performed host-switching experiments, with a total of six aphid species, five of which D. rapae parasitizes in France. We tested cross-breeding ability between strains to detect potential reproductive isolation linked to aphid host species in D. rapae. The strain reared on non-pest aphids was able to develop on aphid species from both cultivated and uncultivated plants. The strains reared on pest aphids, however, exclusively parasitized aphid species on cultivated Brassicaceae. In addition, reproductive isolation was detected between strains from uncultivated and cultivated plants. Thus, the D. rapae populations examined here appear to be showing ecological specialization or they may even be composed of a complex of cryptic species related to the aphid hosts. The role of Chenopodium album as a reservoir for D. rapae, by providing a habitat for non-pest aphids on which it can feed, appears to be severely limited, and thus its efficiency to maintain local populations of D. rapae in the vicinity of crops is questionable.

  9. Contribution of Noncolonizing Aphids to Potato Virus Y Prevalence in Potato in Idaho.

    Science.gov (United States)

    Mondal, Shaonpius; Wenninger, Erik J; Hutchinson, Pamela J S; Weibe, Monica A; Eigenbrode, Sanford D; Bosque-Pérez, Nilsa A

    2016-12-01

    Potato virus Y (PVY) is a major concern for potato production in the United States given its impact on both crop quality and yield. Although green peach aphid, Myzus persicae (Sulzer), is the most efficient PVY vector, it may be less abundant in potato-growing areas of Idaho relative to non-potato-colonizing aphid vectors of PVY that may disperse from nearby cereal fields and other crops. A field study was conducted during 2012-2013 to examine if noncolonizing aphids disperse to nearby potato fields as cereal crops dry down before harvest. The aphid fauna was sampled weekly in four different potato fields in south-central and southeastern Idaho using yellow sticky traps and yellow pan traps. Potato fields were chosen with an adjacent cereal field such that the prevailing westerly wind would facilitate aphid dispersal from cereal fields to potato. Non-potato-colonizing aphids sampled included 10 cereal aphid species, the most abundant of which were Rhopalosiphum padi L. and Metopolophium dirhodum (Walker). More than 35 species from noncereal hosts also were found. Overall, green peach aphid abundance was relatively low, ranging from 0.5-2.5% of the total aphid capture between years and among fields. In both years and all locations, cereal aphid abundance peaked in mid- to late July (cereal ripening stage) and decreased thereafter as cereal crops dried. PVY prevalence in the potato fields increased following these increases in aphid abundance. This study suggests that cereal aphids and other noncolonizing aphids are important contributors to PVY prevalence in potato in southern Idaho. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. Irregular Morphing for Real-Time Rendering of Large Terrain

    Directory of Open Access Journals (Sweden)

    S. Kalem

    2016-06-01

    Full Text Available The following paper proposes an alternative approach to the real-time adaptive triangulation problem. A new region-based multi-resolution approach for terrain rendering is described which improves on-the-fly the distribution of the density of triangles inside the tile after selecting appropriate Level-Of-Detail by an adaptive sampling. This proposed approach organizes the heightmap into a QuadTree of tiles that are processed independently. This technique combines the benefits of both Triangular Irregular Network approach and region-based multi-resolution approach by improving the distribution of the density of triangles inside the tile. Our technique morphs the initial regular grid of the tile to deformed grid in order to minimize approximation error. The proposed technique strives to combine large tile size and real-time processing while guaranteeing an upper bound on the screen space error. Thus, this approach adapts terrain rendering process to local surface characteristics and enables on-the-fly handling of large amount of terrain data. Morphing is based-on the multi-resolution wavelet analysis. The use of the D2WT multi-resolution analysis of the terrain height-map speeds up processing and permits to satisfy an interactive terrain rendering. Tests and experiments demonstrate that Haar B-Spline wavelet, well known for its properties of localization and its compact support, is suitable for fast and accurate redistribution. Such technique could be exploited in client-server architecture for supporting interactive high-quality remote visualization of very large terrain.

  11. Fast, clash-free RNA conformational morphing using molecular junctions.

    Science.gov (United States)

    Héliou, Amélie; Budday, Dominik; Fonseca, Rasmus; van den Bedem, Henry

    2017-07-15

    Non-coding ribonucleic acids (ncRNA) are functional RNA molecules that are not translated into protein. They are extremely dynamic, adopting diverse conformational substates, which enables them to modulate their interaction with a large number of other molecules. The flexibility of ncRNA provides a challenge for probing their complex 3D conformational landscape, both experimentally and computationally. Despite their conformational diversity, ncRNAs mostly preserve their secondary structure throughout the dynamic ensemble. Here we present a kinematics-based procedure to morph an RNA molecule between conformational substates, while avoiding inter-atomic clashes. We represent an RNA as a kinematic linkage, with fixed groups of atoms as rigid bodies and rotatable bonds as degrees of freedom. Our procedure maintains RNA secondary structure by treating hydrogen bonds between base pairs as constraints. The constraints define a lower-dimensional, secondary-structure constraint manifold in conformation space, where motions are largely governed by molecular junctions of unpaired nucleotides. On a large benchmark set, we show that our morphing procedure compares favorably to peer algorithms, and can approach goal conformations to within a low all-atom RMSD by directing fewer than 1% of its atoms. Our results suggest that molecular junctions can modulate 3D structural rearrangements, while secondary structure elements guide large parts of the molecule along the transition to the correct final conformation. The source code, binaries and data are available at https://simtk.org/home/kgs . amelie.heliou@polytechnique.edu or vdbedem@stanford.edu. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  12. Camouflage Effects of Various Colour-Marking Morphs against Different Microhabitat Backgrounds in a Polymorphic Pygmy Grasshopper Tetrix japonica

    Science.gov (United States)

    Tsurui, Kaori; Honma, Atsushi; Nishida, Takayoshi

    2010-01-01

    Background Colour-marking polymorphism is widely distributed among cryptic species. To account for the adaptive significance of such polymorphisms, several hypotheses have been proposed to date. Although these hypotheses argue over the degree of camouflage effects of marking morphs (and the interactions between morphs and their microhabitat backgrounds), as far as we know, most empirical evidence has been provided under unnatural conditions (i.e., using artificial prey). Methodology/Principal Findings Tetrix japonica, a pygmy grasshopper, is highly polymorphic in colour-markings and occurs in both sand and grass microhabitats. Even within a microhabitat, T. japonica is highly polymorphic. Using humans as dummy predators and printed photographs in which various morphs of grasshoppers were placed against different backgrounds, we addressed three questions to test the neutral, background heterogeneity, and differential crypsis hypotheses in four marking-type morphs: 1) do the morphs differ in the degree of crypsis in each microhabitat, 2) are different morphs most cryptic in specific backgrounds of the microhabitats, and 3) does the morph frequency reflect the degree of crypsis? Conclusions/Significance The degree of camouflage differed among the four morphs; therefore, the neutral hypothesis was rejected. Furthermore, the order of camouflage advantage among morphs differed depending on the two types of backgrounds (sand and grass), although the grass background consistently provided greater camouflage effects. Thus, based on our results, we could not reject the background heterogeneity hypothesis. Under field conditions, the more cryptic morphs comprised a minority of the population. Overall, our results demonstrate that the different morphs were not equivalent in the degree of crypsis, but the degree of camouflage of the morphs was not consistent with the morph frequency. These findings suggest that trade-offs exist between the camouflage benefit of body colouration

  13. Camouflage effects of various colour-marking morphs against different microhabitat backgrounds in a polymorphic pygmy grasshopper Tetrix japonica.

    Directory of Open Access Journals (Sweden)

    Kaori Tsurui

    2010-07-01

    Full Text Available Colour-marking polymorphism is widely distributed among cryptic species. To account for the adaptive significance of such polymorphisms, several hypotheses have been proposed to date. Although these hypotheses argue over the degree of camouflage effects of marking morphs (and the interactions between morphs and their microhabitat backgrounds, as far as we know, most empirical evidence has been provided under unnatural conditions (i.e., using artificial prey.Tetrix japonica, a pygmy grasshopper, is highly polymorphic in colour-markings and occurs in both sand and grass microhabitats. Even within a microhabitat, T. japonica is highly polymorphic. Using humans as dummy predators and printed photographs in which various morphs of grasshoppers were placed against different backgrounds, we addressed three questions to test the neutral, background heterogeneity, and differential crypsis hypotheses in four marking-type morphs: 1 do the morphs differ in the degree of crypsis in each microhabitat, 2 are different morphs most cryptic in specific backgrounds of the microhabitats, and 3 does the morph frequency reflect the degree of crypsis?The degree of camouflage differed among the four morphs; therefore, the neutral hypothesis was rejected. Furthermore, the order of camouflage advantage among morphs differed depending on the two types of backgrounds (sand and grass, although the grass background consistently provided greater camouflage effects. Thus, based on our results, we could not reject the background heterogeneity hypothesis. Under field conditions, the more cryptic morphs comprised a minority of the population. Overall, our results demonstrate that the different morphs were not equivalent in the degree of crypsis, but the degree of camouflage of the morphs was not consistent with the morph frequency. These findings suggest that trade-offs exist between the camouflage benefit of body colouration and other fitness components, providing a better

  14. Shallot aphids, Myzus ascalonicus, in strawberry

    DEFF Research Database (Denmark)

    Enkegaard, Annie; Sigsgaard, Lene; Kristensen, Kristian

    2013-01-01

    to either inoculative or inundative biocontrol of shallot aphids in strawberry. The three predators studied were the green lacewing, Chrysoperla carnea Steph. (Neuroptera: Chrysopi-dae), the two-spotted lady beetle, Adalia bipunctata L. (Coleoptera: Coccinellidae), and the gall midge Aphidoletes aphidimyza...

  15. Stability of soybean aphid resistance in soybean across different temperatures

    Science.gov (United States)

    The soybean aphid, Aphis glycines Matsumura, is the most important insect pest posing a threat to soybean, Glycine max (L.) Merr., grain production in the United States. Soybean cultivars with resistance are currently being deployed to aid in management of the pest. Temperature has been reported to ...

  16. Resistance source to cowpea aphid (Aphis craccivora Koch) in ...

    African Journals Online (AJOL)

    The present study evaluated the resistance of 7 varieties of the broad bean Vicia faba L. to cowpea aphid, Aphis craccivora Koch, 1854. These landraces from the region of Biskra (in the south of Algeria) were selected in an initial field trial and subjected to further testing in the greenhouse. Landrace V51 proved to be the ...

  17. Presence of the aphid, Chaetosiphon fragaefolii, on strawberry in Argentina.

    Science.gov (United States)

    Cédola, Claudia; Grecob, Nancy

    2010-01-01

    Seasonal abundance of the strawberry aphid complex under different agronomic practices in the outskirts of La Plata, Argentina was studied on strawberry, Fragaria x ananassa Duchesne (Rosales: Rosaceae). Aphid densities were low in strawberry fields in which insecticides and fungicides were used. In addition to Aphis gossypii, Aphis fabae, Mysus persicae and Macrosiphum euphorbiae, the aphid, Chaetosiphon fragaefolii (Cockerell) (Homoptera: Aphididae), was recorded for the first time in this horticultural area. Life history and some demographic parameters were calculated for C. fragaefolii. The mean duration of nymphal stages was 10.44 days, the oviposition period was 11.8 days, and the mean number of nymph/female/day was 2.4 +/- 0.3. Demographic parameters analyzed included the net reproductive rate R(o) = 14.55 +/- 0.096 nymph/female, generation time T=16.91 +/- 0.035 days, and the intrinsic rate of increase r(m) = 0.158 +/- (0.004). No parasites were found associated with C. fragaefolli. The pathogenic fungus, Entomophthora planchoniana Cornu (Zygomycetes: Entomophthorales) was the main mortality factor. Although aphids are not the main pests in strawberry fields, C. fragaefolii can be a serious problem because it can transmit several virus diseases of strawberry. Greater knowledge of life history traits and mortality factors of this species is needed in order to design appropriate control strategies.

  18. Recent characterization of cowpea aphid-borne mosaic virus ...

    African Journals Online (AJOL)

    Woodiness disease is the most important disorder of passion fruit worldwide. The causal agent in Brazil is the Cowpea aphid-borne mosaic virus (CABMV), and despite the economic relevance of passion fruit for agriculture there have been recently very few studies about this virus in Brazil and worldwide. This work reveals ...

  19. Control of whiteflies and aphids in tomato ( Solanum lycopersicum L ...

    African Journals Online (AJOL)

    Whitefly (Bemisia tabaci, Homoptera: Aleyrodidae) and aphid (Homoptera) on tomato (Solanum lycopersicum L.) are economically important insect pests that are difficult to manage due to their resistance to a wide range of chemical pesticides. Field experiments were conducted to assess the effects of fermented plant ...

  20. Is the response of aphids to alarm pheromone stable?

    Czech Academy of Sciences Publication Activity Database

    Thieme, T.; Dixon, Anthony F. G.

    2015-01-01

    Roč. 139, č. 10 (2015), s. 741-746 ISSN 0931-2048 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : (E)-β-farnesene * dropping response * habituation * Leguminosae * pea aphid Subject RIV: EH - Ecology, Behaviour Impact factor: 1.517, year: 2015

  1. Predator efficiency reconsidered for a ladybird-aphid system

    Czech Academy of Sciences Publication Activity Database

    Kindlmann, Pavel; Yasuda, H.; Kajita, Y.; Sato, S.; Dixon, Anthony F. G.

    2015-01-01

    Roč. 3, mar (2015), s. 27 ISSN 2296-701X R&D Projects: GA MŠk(CZ) LO1415; GA ČR GB14-36098G Institutional support: RVO:67179843 Keywords : biological control * generation time ratio * population dynamics * predator-prey systems * ladybirds * aphids Subject RIV: EH - Ecology, Behaviour

  2. Resistance source to cowpea aphid (Aphis craccivora Koch) in ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-07-18

    Jul 18, 2008 ... The present study evaluated the resistance of 7 varieties of the broad bean Vicia faba L. to cowpea aphid, Aphis craccivora Koch, 1854. These landraces from the region of Biskra (in the south of Algeria) were selected in an initial field trial and subjected to further testing in the greenhouse. Landrace V51.

  3. Sugarcane aphid spatial distribution in grain sorghum fields

    Science.gov (United States)

    Sorghum is an important summer grain crop in the United States. In 2014, the U.S. produced 432 million bushels of sorghum valued at $1.67 billion on more than 6 million acres. The sugarcane aphid, Melanaphis sacchari (Zehntner), was discovered in damaging numbers in grain sorghum, Sorghum bicolor ...

  4. Enhancement of resistance to aphids by introducing the snowdrop ...

    Indian Academy of Sciences (India)

    The toxicity of GNA-expressing plants to aphids has also been studied. The independently derived plants were subjected to molecular analyses. Polymerase chain reaction (PCR) and Southern blot analyses confirmed that the gna gene was integrated into maize genome and inherited to the following generations.

  5. Aspects of the Biology of the Carrot Aphid Chomaphis (dysaphis ...

    African Journals Online (AJOL)

    1958), and often covered with soil. Although C.foeniculus has hitherto not been reported from Uganda, recent observations at. Makerere University Agricultural Research In- stitute, Kabanyolo (MUARIK), suggest that sig- nificant infestation of carrots by the aphid oc- curs in the country. Given this pest potential (a.

  6. Diversity of cereal aphid parasitoids in simple and complex landscapes

    NARCIS (Netherlands)

    Vollhardt, I.M.G.; Tscharntke, T.; Wackers, F.L.; Bianchi, F.J.J.A.; Thies, C.

    2008-01-01

    Structurally complex landscapes may enhance local species richness and interactions, which is possibly due to a higher species pool in complex landscapes. This hypothesis was tested using cereal aphid parasitoids (Hymenoptera, Aphidiidae) by comparing 12 winter wheat fields in structurally complex

  7. Short Communication: Occurrence of the pea aphid, Acyrthosiphon ...

    African Journals Online (AJOL)

    The occurrence of pea aphid, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae), on wild annual and perennial leguminous plants was studied at two locations (Adet and Wondata) in West Gojam, Ethiopia in 1999/2000 seasons. Annual and perennial leguminous wild or volunteer plants encountered in the study areas ...

  8. occurrence of the pea aphid, acyrthosiphon pisum (harris)

    African Journals Online (AJOL)

    Preferred Customer

    alfalfa (Medicago sativa), clover (Trifolium sp.) and other leguminous crops ... holocyclic life cycle (i.e., it reproduces parthenogenetically ... Table 1. Plant species infested by pea aphid at Adet and. Wondata, Ethiopia, in 1999/2000. Host plant species. Total. Number of plants. Vetch Clover Lupine. Alfalfa. Infested plants.

  9. Trichoderma harzianum enhances tomato indirect defense against aphids.

    Science.gov (United States)

    Coppola, Mariangela; Cascone, Pasquale; Chiusano, Maria Luisa; Colantuono, Chiara; Lorito, Matteo; Pennacchio, Francesco; Rao, Rosa; Woo, Sheridan Lois; Guerrieri, Emilio; Digilio, Maria Cristina

    2017-12-01

    Many fungal root symbionts of the genus Trichoderma are well-known for their beneficial effects on agronomic performance and protection against plant pathogens; moreover, they may enhance protection from insect pests, by triggering plant resistance mechanisms. Defense barriers against insects are induced by the activation of metabolic pathways involved in the production of defense-related plant compounds, either directly active against herbivore insects, or exerting an indirect effect, by increasing the attraction of herbivore natural enemies. In a model system composed of the tomato plant, the aphid Macrosiphum euphorbiae and the parasitoid Aphidius ervi, plant metabolic changes induced by Trichoderma harzianum and their effects on higher trophic levels have been assessed. T. harzianum T22 treatments induce a primed state that upon aphid attacks leads to an increased attraction of aphid parasitoids, mediated by the enhanced production of volatile organic compounds (VOCs) that are known to induce Aphidius ervi flight. Transcriptome sequencing of T22-treated plants infested by aphids showed a remarkable upregulation of genes involved in terpenoids biosynthesis and salicylic acid pathway, which are consistent with the observed flight response of A. ervi and the VOC bouquet profile underlying this behavioral response. © 2017 Institute of Zoology, Chinese Academy of Sciences.

  10. Bird cherry-oat aphid: do we have resistance?

    Science.gov (United States)

    Bird cherry-oat aphid (BCOA), Rhopalosiphum padi (L.), is a highly efficient, non-propagative, persistent vector of the phloem limited leutovirus BYD-PAV. BYD is the most important viral disease of cereal grains in the world and PAV is the most prevalent strain of BYD in North America. Not all BCO...

  11. Local predators attack exotic aphid Brachycaudus divaricatae in Lithuania

    Czech Academy of Sciences Publication Activity Database

    Danilov, J.; Rakauskas, R.; Havelka, Jan; Starý, Petr

    2016-01-01

    Roč. 69, č. 2 (2016), s. 263-269 ISSN 1721-8861 Institutional support: RVO:60077344 Keywords : Prunus * Aphids * Brachycaudus divaricatae Subject RIV: EH - Ecology, Behaviour Impact factor: 1.051, year: 2016 http://www.bulletinofinsectology.org/pdfarticles/vol69-2016-263-269danilov.pdf

  12. Suitability of an artificial diet for rape aphid, Brevicoryne brassicae ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-09-15

    Sep 15, 2009 ... discs (a) and artificial diet (b). structure of our testing material and show just the effect of that. The results in this investigation showed that this artificial diet can support all life stages of B. brassicae and this aphid can be established on that. The compare- son of results with life table parameters that Francisco.

  13. Transgenic plants expressing the coat protein gene of cowpea aphid ...

    African Journals Online (AJOL)

    Cowpea aphid-borne mosaic virus (CABMV) is a potyvirus that infects cowpea causing significant yield reduction. However, there is no durable natural resistance to the virus within the crop and genetic engineering for virus resistance was not possible because of a lack of an efficient, reliable and reproducible cowpea ...

  14. Molecular characterization of aphid resistance in black raspberry germplasm

    Science.gov (United States)

    Black raspberry is a minor but lucrative crop with most of the acreage in the U.S. found in Oregon. Rapid decline of plantings results from virus infection vectored by the North American large raspberry aphid and is the most limiting factor for growing black raspberry. Existing cultivars are suscept...

  15. Development of REvolutionary Adaptive Morphing UAV (DREAM-UAV), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NextGen Aeronautics, Inc. proposes the development of the innovative use of morphing structures for maneuver and flight control as a project for NASA?s Revolutionary...

  16. Wireless and Distributed Sensing of Shape and Health Monitoring of Morphing Structures

    National Research Council Canada - National Science Library

    Smoker, Jason; Baz, Amr

    2008-01-01

    This paper presents the development of the theoretical basis for the design of sensor networks for determining the 2-dimensional shape of morphing structures by monitoring simultaneously the bending...

  17. Research on water-exit and take-off process for Morphing Unmanned Submersible Aerial Vehicle

    Science.gov (United States)

    Hu, Jun-hua; Xu, Bao-wei; Feng, Jin-fu; Qi, Duo; Yang, Jian; Wang, Cong

    2017-04-01

    This paper presents a theoretic implementation method of Morphing Unmanned Submersible Aerial Vehicle (MUSAV), which can both submerge in the water and fly in the air. Two different shapes are put forward so that the vehicle can suit both submergence and flight, considering the tremendous differences between hydrodynamic configuration and aerodynamic configuration of a vehicle. The transition of the two shapes can be achieved by using morphing technology. The water-to-air process, including water-exit, morphing, take-off and steady flight, is analyzed. The hydrodynamic and aerodynamic model of the vehicle exiting the water surface obliquely and then taking off into the air has been founded. The control strategy after morphing is analyzed and the control method is given. Numerical method is used to validate the motion model of the water-exit process. Results of simulations show the validity of the proposed model and the feasibility of MUSAV in theory.

  18. GPM GROUND VALIDATION NOAA CPC MORPHING TECHNIQUE (CMORPH) IFLOODS V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GPM Ground Validation NOAA CPC Morphing Technique (CMORPH) IFloodS dataset consists of global precipitation analyses data produced by the NOAA Climate Prediction...

  19. GPM GROUND VALIDATION NOAA CPC MORPHING TECHNIQUE (CMORPH) IPHEX V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GPM Ground Validation NOAA CPC Morphing Technique (CMORPH) IPHEx dataset consists of global precipitation analyses data produced by the NOAA Climate Prediction...

  20. Behavioral dominance between female color morphs of a Lake Victoria cichlid fish

    NARCIS (Netherlands)

    Dijkstra, Peter D.; van Dijk, Sander; Groothuis, Ton G. G.; Pierotti, Michele E. R.; Seehausen, Ole

    2009-01-01

    Species that exhibit genetic color polymorphism are suitable for studying the evolutionary forces that maintain heritable phenotypic variation in nature. Male color morphs often differ in behavioral dominance, affecting the evolution of color polymorphisms. However, behavioral dominance among female

  1. Circulative Nonpropagative Aphid Transmission of Nanoviruses: an Oversimplified View

    Science.gov (United States)

    Sicard, Anne; Zeddam, Jean-Louis; Yvon, Michel; Michalakis, Yannis; Gutiérrez, Serafin

    2015-01-01

    ABSTRACT Plant virus species of the family Nanoviridae have segmented genomes with the highest known number of segments encapsidated individually. They thus likely represent the most extreme case of the so-called multipartite, or multicomponent, viruses. All species of the family are believed to be transmitted in a circulative nonpropagative manner by aphid vectors, meaning that the virus simply crosses cellular barriers within the aphid body, from the gut to the salivary glands, without replicating or even expressing any of its genes. However, this assumption is largely based on analogy with the transmission of other plant viruses, such as geminiviruses or luteoviruses, and the details of the molecular and cellular interactions between aphids and nanoviruses are poorly investigated. When comparing the relative frequencies of the eight genome segments in populations of the species Faba bean necrotic stunt virus (FBNSV) (genus Nanovirus) within host plants and within aphid vectors fed on these plants, we unexpectedly found evidence of reproducible changes in the frequencies of some specific segments. We further show that these changes occur within the gut during early stages of the virus cycle in the aphid and not later, when the virus is translocated into the salivary glands. This peculiar observation, which was similarly confirmed in three aphid vector species, Acyrthosiphon pisum, Aphis craccivora, and Myzus persicae, calls for revisiting of the mechanisms of nanovirus transmission. It reveals an unexpected intimate interaction that may not fit the canonical circulative nonpropagative transmission. IMPORTANCE A specific mode of interaction between viruses and arthropod vectors has been extensively described in plant viruses in the three families Luteoviridae, Geminiviridae, and Nanoviridae, but never in arboviruses of animals. This so-called circulative nonpropagative transmission contrasts with the classical biological transmission of animal arboviruses in that

  2. Plant-generated artificial small RNAs mediated aphid resistance.

    Directory of Open Access Journals (Sweden)

    Hongyan Guo

    Full Text Available BACKGROUND: RNA silencing is an important mechanism for regulation of endogenous gene expression and defense against genomic intruders in plants. This natural defense system was adopted to generate virus-resistant plants even before the mechanism of RNA silencing was unveiled. With the clarification of that mechanism, transgenic antiviral plants were developed that expressed artificial virus-specific hairpin RNAs (hpRNAs or microRNAs (amiRNAs in host plants. Previous works also showed that plant-mediated RNA silencing technology could be a practical method for constructing insect-resistant plants by expressing hpRNAs targeting essential genes of insects. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we chose aphid Myzus persicae of order Hemiptera as a target insect. To screen for aphid genes vulnerable to attack by plant-mediated RNA silencing to establish plant aphid resistance, we selected nine genes of M. persicae as silencing targets, and constructed their hpRNA-expressing vectors. For the acetylcholinesterase 2 coding gene (MpAChE2, two amiRNA-expressing vectors were also constructed. The vectors were transformed into tobacco plants (Nicotiana tabacum cv. Xanti. Insect challenge assays showed that most of the transgenic plants gained aphid resistance, among which those expressing hpRNAs targeting V-type proton ATPase subunit E-like (V-ATPaseE or tubulin folding cofactor D (TBCD genes displayed stronger aphicidal activity. The transgenic plants expressing amiRNAs targeting two different sites in the MpAChE2 gene exhibited better aphid resistance than the plants expressing MpAChE2-specific hpRNA. CONCLUSIONS/SIGNIFICANCE: Our results indicated that plant-mediated insect-RNA silencing might be an effective way to develop plants resistant to insects with piercing-sucking mouthparts, and both the selection of vulnerable target genes and the biogenetic type of the small RNAs were crucial for the effectiveness of aphid control. The expression of

  3. Gene Expression Analysis of Parthenogenetic Embryonic Development of the Pea Aphid, Acyrthosiphon pisum, Suggests That Aphid Parthenogenesis Evolved from Meiotic Oogenesis

    Science.gov (United States)

    Srinivasan, Dayalan G.; Abdelhady, Ahmed; Stern, David L.

    2014-01-01

    Aphids exhibit a form of phenotypic plasticity, called polyphenism, in which genetically identical females reproduce sexually during one part of the life cycle and asexually (via parthenogenesis) during the remainder of the life cycle. The molecular basis for aphid parthenogenesis is unknown. Cytological observations of aphid parthenogenesis suggest that asexual oogenesis evolved either through a modification of meiosis or from a mitotic process. As a test of these alternatives, we assessed the expression levels and expression patterns of canonical meiotic recombination and germline genes in the sexual and asexual ovaries of the pea aphid, Acyrthosiphon pisum. We observed expression of all meiosis genes in similar patterns in asexual and sexual ovaries, with the exception that some genes encoding Argonaute-family members were not expressed in sexual ovaries. In addition, we observed that asexual aphid tissues accumulated unspliced transcripts of Spo11, whereas sexual aphid tissues accumulated primarily spliced transcripts. In situ hybridization revealed Spo11 transcript in sexual germ cells and undetectable levels of Spo11 transcript in asexual germ cells. We also found that an obligately asexual strain of pea aphid produced little spliced Spo11 transcript. Together, these results suggest that parthenogenetic oogenesis evolved from a meiosis-like, and not a mitosis-like, process and that the aphid reproductive polyphenism may involve a modification of Spo11 gene activity. PMID:25501006

  4. Gene expression analysis of parthenogenetic embryonic development of the pea aphid, Acyrthosiphon pisum, suggests that aphid parthenogenesis evolved from meiotic oogenesis.

    Science.gov (United States)

    Srinivasan, Dayalan G; Abdelhady, Ahmed; Stern, David L

    2014-01-01

    Aphids exhibit a form of phenotypic plasticity, called polyphenism, in which genetically identical females reproduce sexually during one part of the life cycle and asexually (via parthenogenesis) during the remainder of the life cycle. The molecular basis for aphid parthenogenesis is unknown. Cytological observations of aphid parthenogenesis suggest that asexual oogenesis evolved either through a modification of meiosis or from a mitotic process. As a test of these alternatives, we assessed the expression levels and expression patterns of canonical meiotic recombination and germline genes in the sexual and asexual ovaries of the pea aphid, Acyrthosiphon pisum. We observed expression of all meiosis genes in similar patterns in asexual and sexual ovaries, with the exception that some genes encoding Argonaute-family members were not expressed in sexual ovaries. In addition, we observed that asexual aphid tissues accumulated unspliced transcripts of Spo11, whereas sexual aphid tissues accumulated primarily spliced transcripts. In situ hybridization revealed Spo11 transcript in sexual germ cells and undetectable levels of Spo11 transcript in asexual germ cells. We also found that an obligately asexual strain of pea aphid produced little spliced Spo11 transcript. Together, these results suggest that parthenogenetic oogenesis evolved from a meiosis-like, and not a mitosis-like, process and that the aphid reproductive polyphenism may involve a modification of Spo11 gene activity.

  5. Transcriptomic responses of the aphid Myzus persicae nicotianae Blackman (Hemiptera: Aphididae to insecticides: Analyses in the single Chilean clone of the tobacco aphid

    Directory of Open Access Journals (Sweden)

    Marco Cabrera-Brandt

    2014-04-01

    Full Text Available The tobacco aphid Myzus persicae nicotianae Blackman is a subspecies of the highly polyphagous and agricultural pest Myzus persicae (Sulzer. For its control, insecticide applications are widely used, but resistance to numerous molecules has been reported, displaying at least three insecticide resistance mechanisms, including: (i elevated carboxylesterases (E-Carb, (ii modification of the acetylcholinesterase (MACE, and (iii kdr and super-kdr insensitivity mutations. In Chile, populations of the tobacco aphid are characterized by the presence of a single predominant clone, which is also present in high proportions in other countries of the Americas. This aphid clone exhibits low levels of carboxylesterase activity and is kdr susceptible, but the MACE mechanism of insecticide resistance has not been studied. In order to characterize the tobacco aphid in terms of the MACE mechanism and to identify a preliminary group of aphid genes putatively involved in insecticide resistance, a cDNA microarray was used to study the transcriptomic responses when aphids are sprayed with a carbamate insecticide. The single Chilean clone of the tobacco aphid was characterized as MACE susceptible, but we found 38 transcripts significantly regulated by insecticide exposure (13 up- and 25 down-regulated genes. The expression of six of them was validated by qRT-PCR experiments at several time points (6, 12, 18, 24, 30, 36, and 42 h after insecticide application. This mutational and transcriptomic characterization of the tobacco aphid responding to insecticide spray opens new hypotheses in the understanding of the molecular mechanisms underlying insecticide resistance.

  6. Blooming Knit Flowers: Loop-Linked Soft Morphing Structures for Soft Robotics.

    Science.gov (United States)

    Han, Min-Woo; Ahn, Sung-Hoon

    2017-04-01

    A loop-linked structure, which is capable of morphing in various modes, including volumetric transformation, is developed based on knitting methods. Morphing flowers (a lily-like, a daffodil-like, gamopetalous, and a calla-like flower) are fabricated using loop patterning, and their blooming motion is demonstrated by controlling a current that selectively actuates the flowers petals. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Experimental Investigation of Aerodynamic Performance of Airfoils Fitted with Morphing Trailing Edges

    OpenAIRE

    Ai, Qing; Kamliya Jawahar, Hasan; Azarpeyvand, Mahdi

    2016-01-01

    The aerodynamic performance and wake development of a NACA 0012 airfoil fitted with morphing trailing edges were studied using experimental and computational techniques. The NACA 0012 airfoil was tested with morphing trailing edges having various camber profiles with the same trailing edge tip deflection. The aerodynamic force measurements for the airfoil were carried out for a wide range of chord-based Reynolds number and angles of attack with trailing edge deflection angle of β= 5◦ and 10◦....

  8. Structural design and analysis of morphing skin embedded with pneumatic muscle fibers

    International Nuclear Information System (INIS)

    Chen, Yijin; Yin, Weilong; Leng, Jinsong; Liu, Yanju

    2011-01-01

    In this paper, a kind of morphing skin embedded with pneumatic muscle fibers is proposed from the bionics perspective. The elastic modulus of the designed pneumatic muscle fibers is experimentally determined and their output force is tested with internal air pressure varying from 0 to 0.4 MPa. The experimental results show that the contraction ratio of the pneumatic muscle fibers using the given material could reach up to 26.8%. Isothermal tensile tests are conducted on the fabricated morphing skin, and the results are compared with theoretical predictions based on the rule of mixture. When the strain is lower than 3% and in its linear-elastic range, the rule of mixture is proved to possess satisfying accuracy in the prediction of the elastic modulus of the morphing skin. Subsequently, the output force of the morphing skin is tested. It is revealed that when the volume ratio of the pneumatic muscle fibers is 0.228, the contraction ratio can reach up to 17.8%, which is satisfactory for meeting the camber requirement of morphing skin with maximum strain level below 2%. Finally, stress-bearing capability tests of the morphing skin on local uniformly distributed loads are conducted, and the test results show that the transverse stiffness of the morphing skin can be regulated by changing the internal air pressure. Under a uniformly distributed load of 540 Pa, the designed morphing skin is capable of varying by more than two orders of magnitude in the transverse stiffness by changing the internal air pressure

  9. Structural design and analysis of morphing skin embedded with pneumatic muscle fibers

    Science.gov (United States)

    Chen, Yijin; Yin, Weilong; Liu, Yanju; Leng, Jinsong

    2011-08-01

    In this paper, a kind of morphing skin embedded with pneumatic muscle fibers is proposed from the bionics perspective. The elastic modulus of the designed pneumatic muscle fibers is experimentally determined and their output force is tested with internal air pressure varying from 0 to 0.4 MPa. The experimental results show that the contraction ratio of the pneumatic muscle fibers using the given material could reach up to 26.8%. Isothermal tensile tests are conducted on the fabricated morphing skin, and the results are compared with theoretical predictions based on the rule of mixture. When the strain is lower than 3% and in its linear-elastic range, the rule of mixture is proved to possess satisfying accuracy in the prediction of the elastic modulus of the morphing skin. Subsequently, the output force of the morphing skin is tested. It is revealed that when the volume ratio of the pneumatic muscle fibers is 0.228, the contraction ratio can reach up to 17.8%, which is satisfactory for meeting the camber requirement of morphing skin with maximum strain level below 2%. Finally, stress-bearing capability tests of the morphing skin on local uniformly distributed loads are conducted, and the test results show that the transverse stiffness of the morphing skin can be regulated by changing the internal air pressure. Under a uniformly distributed load of 540 Pa, the designed morphing skin is capable of varying by more than two orders of magnitude in the transverse stiffness by changing the internal air pressure.

  10. Ant mimicry by an aphid parasitoid, Lysiphlebus fabarum.

    Science.gov (United States)

    Rasekh, Arash; Michaud, J P; Kharazi-Pakdel, Aziz; Allahyari, Hossein

    2010-01-01

    In Iran, Lysiphlebus fabarum (Marshall) (Hymenoptera: Braconidae: Aphidiinae) is a uniparental parasitoid of the black bean aphid, Aphis fabae Scopoli (Hemiptera: Aphididae), that possesses various highly evolved adaptations for foraging within ant-tended aphid colonies. Direct observations and video recordings were used to analyze the behavior of individual females foraging for A. fabae on bean leaf disks in open arenas in the laboratory. Females exploited aphids as hosts and as a source of food, allocating within-patch time as follows: resting - 10.4%, grooming - 8.2%, searching - 11.5%, antennation (host recognition) - 7.5%, antennation (honeydew solicitation mimicking ants) - 31.9%, abdominal bending (attack preparation) 19.7%, probing with the ovipositor (attack) - 10.8%. The mean handling time for each aphid encountered was 2.0 ± 0.5 min. Females encountered an average of 47.4 ± 6.4 aphids per hour, but laid only 1.2 eggs per hour. The ovipositor insertion time for parasitism ranged from 2 sec to longer than a minute, but most insertions did not result in an egg being laid. A. fabae defensive behaviors included kicking, raising and swiveling the body, and attempts to smear the attacker with cornicle secretions, sometimes with lethal results. Food deprivation for 4-6 h prior to testing increased the frequency of ant mimcry by L. fabarum. Females also used ant-like antennation to reduce A. fabae defensive behavior, e.g. the frequency of kicking. L. fabarum attacks primed A. fabae to be more responsive to subsequent honeydew solicitation, such that experienced females improved their feeding success by alternating between the roles of parasitoid and ant mimic. These results reveal the possibility for mutualisms to evolve between L. fabarum and the ant species that tend A. fabae, since L. fabarum receive ant protection for their progeny and may benefit the ants by improving A. fabae responsiveness to honeydew solicitation.

  11. High throughput phenotyping for aphid resistance in large plant collections

    Directory of Open Access Journals (Sweden)

    Chen Xi

    2012-08-01

    Full Text Available Abstract Background Phloem-feeding insects are among the most devastating pests worldwide. They not only cause damage by feeding from the phloem, thereby depleting the plant from photo-assimilates, but also by vectoring viruses. Until now, the main way to prevent such problems is the frequent use of insecticides. Applying resistant varieties would be a more environmental friendly and sustainable solution. For this, resistant sources need to be identified first. Up to now there were no methods suitable for high throughput phenotyping of plant germplasm to identify sources of resistance towards phloem-feeding insects. Results In this paper we present a high throughput screening system to identify plants with an increased resistance against aphids. Its versatility is demonstrated using an Arabidopsis thaliana activation tag mutant line collection. This system consists of the green peach aphid Myzus persicae (Sulzer and the circulative virus Turnip yellows virus (TuYV. In an initial screening, with one plant representing one mutant line, 13 virus-free mutant lines were identified by ELISA. Using seeds produced from these lines, the putative candidates were re-evaluated and characterized, resulting in nine lines with increased resistance towards the aphid. Conclusions This M. persicae-TuYV screening system is an efficient, reliable and quick procedure to identify among thousands of mutated lines those resistant to aphids. In our study, nine mutant lines with increased resistance against the aphid were selected among 5160 mutant lines in just 5 months by one person. The system can be extended to other phloem-feeding insects and circulative viruses to identify insect resistant sources from several collections, including for example genebanks and artificially prepared mutant collections.

  12. A two-dimensional iterative panel method and boundary layer model for bio-inspired multi-body wings

    Science.gov (United States)

    Blower, Christopher J.; Dhruv, Akash; Wickenheiser, Adam M.

    2014-03-01

    The increased use of Unmanned Aerial Vehicles (UAVs) has created a continuous demand for improved flight capabilities and range of use. During the last decade, engineers have turned to bio-inspiration for new and innovative flow control methods for gust alleviation, maneuverability, and stability improvement using morphing aircraft wings. The bio-inspired wing design considered in this study mimics the flow manipulation techniques performed by birds to extend the operating envelope of UAVs through the installation of an array of feather-like panels across the airfoil's upper and lower surfaces while replacing the trailing edge flap. Each flap has the ability to deflect into both the airfoil and the inbound airflow using hinge points with a single degree-of-freedom, situated at 20%, 40%, 60% and 80% of the chord. The installation of the surface flaps offers configurations that enable advantageous maneuvers while alleviating gust disturbances. Due to the number of possible permutations available for the flap configurations, an iterative constant-strength doublet/source panel method has been developed with an integrated boundary layer model to calculate the pressure distribution and viscous drag over the wing's surface. As a result, the lift, drag and moment coefficients for each airfoil configuration can be calculated. The flight coefficients of this numerical method are validated using experimental data from a low speed suction wind tunnel operating at a Reynolds Number 300,000. This method enables the aerodynamic assessment of a morphing wing profile to be performed accurately and efficiently in comparison to Computational Fluid Dynamics methods and experiments as discussed herein.

  13. A survey of aphid parasitoids (Hymenoptera: Braconidae: Aphidiinae) of Southeastern Europe and their aphid-plant associations

    Czech Academy of Sciences Publication Activity Database

    Kavallieratos, N. G.; Tomanovic, K.; Starý, Petr; Athanassiou, CH. G.; Sarlis, G. P.; Petrovic, O.; Niketic, M.; Veroniki, M. A.

    2004-01-01

    Roč. 39, č. 3 (2004), s. 527-563 ISSN 0003-6862 R&D Projects: GA AV ČR IAA6007106; GA AV ČR IBS5007102 Institutional research plan: CEZ:AV0Z5007907 Keywords : Aphidiinae * parasitoid -aphid-plant associations * faunistic complexes Subject RIV: EG - Zoology Impact factor: 0.448, year: 2004

  14. Evaluation of mesh morphing and mapping techniques in patient specific modeling of the human pelvis.

    Science.gov (United States)

    Salo, Zoryana; Beek, Maarten; Whyne, Cari Marisa

    2013-01-01

    Robust generation of pelvic finite element models is necessary to understand the variation in mechanical behaviour resulting from differences in gender, aging, disease and injury. The objective of this study was to apply and evaluate mesh morphing and mapping techniques to facilitate the creation and structural analysis of specimen-specific finite element (FE) models of the pelvis. A specimen-specific pelvic FE model (source mesh) was generated following a traditional user-intensive meshing scheme. The source mesh was morphed onto a computed tomography scan generated target surface of a second pelvis using a landmarked-based approach, in which exterior source nodes were shifted to target surface vertices, while constrained along a normal. A second copy of the morphed model was further refined through mesh mapping, in which surface nodes of the initial morphed model were selected in patches and remapped onto the surfaces of the target model. Computed tomography intensity based material properties were assigned to each model. The source, target, morphed and mapped models were analyzed under axial compression using linear static FE analysis and their strain distributions evaluated. Morphing and mapping techniques were effectively applied to generate good quality geometrically complex specimen-specific pelvic FE models. Mapping significantly improved strain concurrence with the target pelvis FE model. Copyright © 2012 John Wiley & Sons, Ltd.

  15. NUMERICAL INVESTIGATION OF TWO ELEMENT CAMBER MORPHING AIRFOIL IN LOW REYNOLDS NUMBER FLOWS

    Directory of Open Access Journals (Sweden)

    RAJESH SENTHIL KUMAR T.

    2017-07-01

    Full Text Available Aerodynamic performance of a two-element camber morphing airfoil was investigated at low Reynolds number using the transient SST model in ANSYS FLUENT 14.0 and eN method in XFLR5. The two-element camber morphing concept was employed to morph the baseline airfoil into another airfoil by altering the orientation of mean-line at 35% of the chord to achieve better aerodynamic efficiency. NACA 0012 was selected as baseline airfoil. NACA 23012 was chosen as the test case as it has the camber-line similar to that of the morphed airfoil and as it has the same thickness as that of the baseline airfoil. The simulations were carried out at chord based Reynolds numbers of 2.5×105 and 3.9×105. The aerodynamic force coefficients, aerodynamic efficiency and the location of the transition point of laminar separation bubble over these airfoils were studied for various angles of attack. It was found that the aerodynamic efficiency of the morphed airfoil was 12% higher than that of the target airfoil at 4° angle of attack for Reynolds number of 3.9×105 and 54% rise in aerodynamic performance was noted as Reynolds number was varied from 2.5×105 to 3.9×105. The morphed airfoil exhibited the nature of low Reynolds number airfoil.

  16. Evaluation of mesh morphing and mapping techniques in patient specific modelling of the human pelvis.

    Science.gov (United States)

    Salo, Zoryana; Beek, Maarten; Whyne, Cari Marisa

    2012-08-01

    Robust generation of pelvic finite element models is necessary to understand variation in mechanical behaviour resulting from differences in gender, aging, disease and injury. The objective of this study was to apply and evaluate mesh morphing and mapping techniques to facilitate the creation and structural analysis of specimen-specific finite element (FE) models of the pelvis. A specimen-specific pelvic FE model (source mesh) was generated following a traditional user-intensive meshing scheme. The source mesh was morphed onto a computed tomography scan generated target surface of a second pelvis using a landmarked-based approach, in which exterior source nodes were shifted to target surface vertices, while constrained along a normal. A second copy of the morphed model was further refined through mesh mapping, in which surface nodes of the initial morphed model were selected in patches and remapped onto the surfaces of the target model. Computed tomography intensity-based material properties were assigned to each model. The source, target, morphed and mapped models were analyzed under axial compression using linear static FE analysis, and their strain distributions were evaluated. Morphing and mapping techniques were effectively applied to generate good quality and geometrically complex specimen-specific pelvic FE models. Mapping significantly improved strain concurrence with the target pelvis FE model. Copyright © 2012 John Wiley & Sons, Ltd.

  17. Arabidopsis thaliana - Myzus persicae interaction: shaping the understanding of plant defense against phloem-feeding aphids

    Directory of Open Access Journals (Sweden)

    Joe eLouis

    2013-07-01

    Full Text Available The phloem provides a unique niche for several organisms. Aphids are a large group of Hemipteran insects that utilize stylets present in their mouthparts to pierce sieve elements and drink large volumes of phloem sap. In addition, many aphids also vector viral diseases. Myzus persicae, commonly known as the green peach aphid (GPA, is an important pest of a large variety of plants that includes Arabidopsis thaliana. This review summarizes recent studies that have exploited the compatible interaction between Arabidopsis and GPA to understand the molecular and physiological mechanisms utilized by plants to control aphid infestation, as well as genes and mechanisms that contribute to susceptibility. In addition, recent efforts to identify aphid-delivered elicitors of plant defenses and novel aphid salivary components that facilitate infestation are also discussed.

  18. Structural Analysis of a Dragonfly Wing

    NARCIS (Netherlands)

    Jongerius, S.R.; Lentink, D.

    2010-01-01

    Dragonfly wings are highly corrugated, which increases the stiffness and strength of the wing significantly, and results in a lightweight structure with good aerodynamic performance. How insect wings carry aerodynamic and inertial loads, and how the resonant frequency of the flapping wings is tuned

  19. Role of the aphid species and their feeding locations in parasitization behavior of Aphelinus abdominalis, a parasitoid of the lettuce aphid Nasonovia ribisnigri

    Science.gov (United States)

    Shrestha, Govinda; Skovgård, Henrik; Reddy, Gadi V. P.; Steenberg, Tove; Enkegaard, Annie

    2017-01-01

    Aphid species feeding on lettuce occupy distinct feeding sites: the lettuce aphid Nasonovia ribisnigri prefers to feed on heart leaves, whereas the potato aphid Macrosiphum euphorbiae feeds only on outer leaves. The aphid parasitoid Aphelinus abdominalis, known to be able to regulate M. euphorbiae on many crops, has recently been indicated as a promising biocontrol candidate also for use against N. ribisnigri, a major pest of lettuce. This study therefore examined A. abdominalis parasitization preference between N. ribisnigri and M. euphorbiae and its ability to parasitize aphids feeding on different parts of lettuce plants. In addition, life history traits of A. abdominalis on these aphid species were investigated. In no-choice laboratory experiments on leaf discs and 24 h exposure, A. abdominalis successfully parasitized 54% and 60% of the offered N. ribisnigri and M. euphorbiae, respectively, with no significant difference. In the corresponding choice experiment, however, A. abdominalis had a tendency for a significantly higher preference for M. euphorbiae (38%) compared to N. ribisnigri (30%). Growth chamber experiments on whole plants demonstrated that A. abdominalis was able to parasitize aphids, regardless of their feeding locations on lettuce plants. However, aphid feeding behavior had a significant effect on the parasitization rate. A. abdominalis parasitized significantly higher percentages of M. euphorbiae or N. ribisnigri when aphids were exposed separately to parasitoids on whole lettuce plants as compared with N. ribisnigri exposed only on heart leaf. A significant preference of A. abdominalis for M. euphorbiae compared to N. ribisnigri was also observed in the growth chamber choice experiment. A high percentage of adult emergence (> 84%) and female-biased sex ratio (> 83%) were found irrespective of the aphid species. PMID:28854232

  20. Role of the aphid species and their feeding locations in parasitization behavior of Aphelinus abdominalis, a parasitoid of the lettuce aphid Nasonovia ribisnigri.

    Science.gov (United States)

    Shrestha, Govinda; Skovgård, Henrik; Reddy, Gadi V P; Steenberg, Tove; Enkegaard, Annie

    2017-01-01

    Aphid species feeding on lettuce occupy distinct feeding sites: the lettuce aphid Nasonovia ribisnigri prefers to feed on heart leaves, whereas the potato aphid Macrosiphum euphorbiae feeds only on outer leaves. The aphid parasitoid Aphelinus abdominalis, known to be able to regulate M. euphorbiae on many crops, has recently been indicated as a promising biocontrol candidate also for use against N. ribisnigri, a major pest of lettuce. This study therefore examined A. abdominalis parasitization preference between N. ribisnigri and M. euphorbiae and its ability to parasitize aphids feeding on different parts of lettuce plants. In addition, life history traits of A. abdominalis on these aphid species were investigated. In no-choice laboratory experiments on leaf discs and 24 h exposure, A. abdominalis successfully parasitized 54% and 60% of the offered N. ribisnigri and M. euphorbiae, respectively, with no significant difference. In the corresponding choice experiment, however, A. abdominalis had a tendency for a significantly higher preference for M. euphorbiae (38%) compared to N. ribisnigri (30%). Growth chamber experiments on whole plants demonstrated that A. abdominalis was able to parasitize aphids, regardless of their feeding locations on lettuce plants. However, aphid feeding behavior had a significant effect on the parasitization rate. A. abdominalis parasitized significantly higher percentages of M. euphorbiae or N. ribisnigri when aphids were exposed separately to parasitoids on whole lettuce plants as compared with N. ribisnigri exposed only on heart leaf. A significant preference of A. abdominalis for M. euphorbiae compared to N. ribisnigri was also observed in the growth chamber choice experiment. A high percentage of adult emergence (> 84%) and female-biased sex ratio (> 83%) were found irrespective of the aphid species.

  1. Role of the aphid species and their feeding locations in parasitization behavior of Aphelinus abdominalis, a parasitoid of the lettuce aphid Nasonovia ribisnigri.

    Directory of Open Access Journals (Sweden)

    Govinda Shrestha

    Full Text Available Aphid species feeding on lettuce occupy distinct feeding sites: the lettuce aphid Nasonovia ribisnigri prefers to feed on heart leaves, whereas the potato aphid Macrosiphum euphorbiae feeds only on outer leaves. The aphid parasitoid Aphelinus abdominalis, known to be able to regulate M. euphorbiae on many crops, has recently been indicated as a promising biocontrol candidate also for use against N. ribisnigri, a major pest of lettuce. This study therefore examined A. abdominalis parasitization preference between N. ribisnigri and M. euphorbiae and its ability to parasitize aphids feeding on different parts of lettuce plants. In addition, life history traits of A. abdominalis on these aphid species were investigated. In no-choice laboratory experiments on leaf discs and 24 h exposure, A. abdominalis successfully parasitized 54% and 60% of the offered N. ribisnigri and M. euphorbiae, respectively, with no significant difference. In the corresponding choice experiment, however, A. abdominalis had a tendency for a significantly higher preference for M. euphorbiae (38% compared to N. ribisnigri (30%. Growth chamber experiments on whole plants demonstrated that A. abdominalis was able to parasitize aphids, regardless of their feeding locations on lettuce plants. However, aphid feeding behavior had a significant effect on the parasitization rate. A. abdominalis parasitized significantly higher percentages of M. euphorbiae or N. ribisnigri when aphids were exposed separately to parasitoids on whole lettuce plants as compared with N. ribisnigri exposed only on heart leaf. A significant preference of A. abdominalis for M. euphorbiae compared to N. ribisnigri was also observed in the growth chamber choice experiment. A high percentage of adult emergence (> 84% and female-biased sex ratio (> 83% were found irrespective of the aphid species.

  2. Effect of outer wing separation on lift and thrust generation in a flapping wing system

    International Nuclear Information System (INIS)

    Mahardika, Nanang; Viet, Nguyen Quoc; Park, Hoon Cheol

    2011-01-01

    We explore the implementation of wing feather separation and lead-lagging motion to a flapping wing. A biomimetic flapping wing system with separated outer wings is designed and demonstrated. The artificial wing feather separation is implemented in the biomimetic wing by dividing the wing into inner and outer wings. The features of flapping, lead-lagging, and outer wing separation of the flapping wing system are captured by a high-speed camera for evaluation. The performance of the flapping wing system with separated outer wings is compared to that of a flapping wing system with closed outer wings in terms of forward force and downward force production. For a low flapping frequency ranging from 2.47 to 3.90 Hz, the proposed biomimetic flapping wing system shows a higher thrust and lift generation capability as demonstrated by a series of experiments. For 1.6 V application (lower frequency operation), the flapping wing system with separated wings could generate about 56% higher forward force and about 61% less downward force compared to that with closed wings, which is enough to demonstrate larger thrust and lift production capability of the separated outer wings. The experiments show that the outer parts of the separated wings are able to deform, resulting in a smaller amount of drag production during the upstroke, while still producing relatively greater lift and thrust during the downstroke.

  3. Impacts of thiamethoxam seed treatment and host plant resistance on the soybean aphid fungal pathogen, Pandora neoaphidis.

    Science.gov (United States)

    Koch, Karrie A; Ragsdale, David W

    2011-12-01

    Since the introduction of soybean aphid, Aphis glycines Matsumura, from Asia, insecticide use in soybean has increased substantially in the north central United States. Insecticide seed treatments and aphid resistant soybean varieties are management tactics that may reduce reliance on foliar applications of broad-spectrum insecticides. Exploring potential nontarget impacts of these technologies will be an important step in incorporating them into aphid management programs. We investigated impacts of thiamethoxam seed treatment and Rag1 aphid resistant soybean on a fungal pathogen of soybean aphid, Pandora neoaphidis (Remaudière & Hennebert) Humber, via open plot and cage studies. We found that although thiamethoxam seed treatment did significantly lower aphid pressure in open plots compared with an untreated control, this reduction in aphid density translated into nonsignificant decreases in fungal disease prevalence in aphids. Furthermore, when aphid densities were approximately equal in seed treated and untreated soybean, no impact on aphid fungal disease was observed. In open plots, Rag1 resistant soybean experienced lower aphid pressure and aphid disease prevalence compared with a nonresistant isoline. However, in cages when aphid densities were equivalent in both resistant and susceptible soybean, resistance had no impact on aphid disease prevalence. The addition of thiamethoxam seed treatment to resistant soybean yielded aphid densities and aphid disease prevalence similar to untreated, resistant soybean. These studies provide evidence that thiamethoxam seed treatments and Rag1 resistance can impact P. neoaphidis via decreased aphid densities; however, this impact is minimal, implying use of seed treatments and host plant resistance are compatible with P. neoaphidis.

  4. Aphid secondary symbionts do not affect prey attractiveness to two species of predatory lady beetles

    OpenAIRE

    Kovacs, Jennifer L.; Wolf, Candice; Voisin, Den?; Wolf, Seth

    2017-01-01

    Heritable symbionts have been found to mediate interactions between host species and their natural enemies in a variety of organisms. Aphids, their facultative symbionts, and their potential fitness effects have been particularly well-studied. For example, the aphid facultative symbiont Regiella can protect its host from infection from a fungal pathogen, and aphids with Hamiltonella are less likely to be parasitized by parasitic wasps. Recent work has also found there to be negative fitness e...

  5. Potential Overwintering Locations of Soybean Aphid (Hemiptera: Aphididae) Colonizing Soybean in Ohio and Wisconsin.

    Science.gov (United States)

    Crossley, Michael S; Hogg, David B

    2015-04-01

    Soybean aphids, Aphis glycines Matsumura, depend on long-distance, wind-aided dispersal to complete their life cycle. Despite our general understanding of soybean aphid biology, little is explicitly known about dispersal of soybean aphids between winter and summer hosts in North America. This study compared genotypic diversity of soybean aphids sampled from several overwintering locations in the Midwest and soybean fields in Ohio and Wisconsin to test the hypothesis that these overwintering locations are sources of the soybean colonists. In addition, air parcel trajectory analyses were used to demonstrate the potential for long-distance dispersal events to occur to or from these overwintering locations. Results suggest that soybean aphids from overwintering locations along the Illinois-Iowa border and northern Indiana-Ohio are potential colonists of soybean in Ohio and Wisconsin, but that Ohio is also colonized by soybean aphids from other unknown overwintering locations. Soybean aphids in Ohio and Wisconsin exhibit a small degree of population structure that is not associated with the locations of soybean fields in which they occur, but that may be related to specific overwintering environments, multiple introductions to North America, or spatial variation in aphid phenology. There may be a limited range of suitable habitat for soybean aphid overwintering, in which case management of soybean aphids may be more effective at their overwintering sites. Further research efforts should focus on discovering more overwintering locations of soybean aphid in North America, and the relative impact of short- and long-distance dispersal events on soybean aphid population dynamics. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Impact of fertilization and granular insecticides on the incidence of tobacco aphid, myzus persicae (sulz)

    International Nuclear Information System (INIS)

    Razaq, A.; Hussain, N.; Khalil, S.K.; Alamzeb

    1989-01-01

    Field studies were conducted on the control of tobacco aphid, Myzus persicase (Sulz) with four granular insecticides, viz, Furadan 3% G, Diazinon 5% g, Thiodan 5% g and Larsban 5% g, with and without NPK fertilization. The aphid population was significantly higher in the fertilized plots compared to the non-fertilized ones. All the four insecticides significantly reduced the aphids density compared to the check. Furada 3% gave best results for the control of this pest. (author)

  7. Sugarcane Aphid (Hemiptera: Aphididae): A New Pest on Sorghum in North America.

    Science.gov (United States)

    Bowling, Robert D; Brewer, Michael J; Kerns, David L; Gordy, John; Seiter, Nick; Elliott, Norman E; Buntin, G David; Way, M O; Royer, T A; Biles, Stephen; Maxson, Erin

    2016-01-01

    In 2013, the sugarcane aphid, Melanaphis sacchari (Zehntner) (Hemiptera: Aphididae), a new invasive pest of sorghum species in North America, was confirmed on sorghum in 4 states and 38 counties in the United States. In 2015, the aphid was reported on sorghum in 17 states and over 400 counties as well as all sorghum-producing regions in Mexico. Ability to overwinter on living annual and perennial hosts in southern sorghum-producing areas and wind-aided movement of alate aphids appear to be the main factors in its impressive geographic spread in North America. Morphological characteristics of the sugarcane aphid include dark tarsi, cornicles, and antennae, allowing easy differentiation from other aphids on the crop. Sugarcane aphid damages sorghum by removing sap and covering plants with honeydew, causing general plant decline and yield loss. Honeydew and sooty mold can disrupt harvesting. The aphid's high reproductive rate on susceptible sorghum hybrids has resulted in reports of yield loss ranging from 10% to greater than 50%. In response, a combination of research-based data and field observations has supported development of state extension identification, scouting, and treatment guides that aid in initiating insecticide applications to prevent yield losses. Highly efficacious insecticides have been identified and when complemented by weekly scouting and use of thresholds, economic loss by sugarcane aphid can be minimized. Some commercial sorghum hybrids are partially resistant to the aphid, and plant breeders have identified other lines with sugarcane aphid resistance. A very diverse community of predators and parasitoids of sugarcane aphid has been identified, and their value to limit sugarcane aphid population growth is under investigation.

  8. Host Preference between Symbiotic and Aposymbiotic Aphis fabae, by the Aphid Parasitoid, Lysiphlebus ambiguus

    Science.gov (United States)

    Cheng, Rui-Xia; Meng, Ling; Mills, Nickolas J; Li, Baoping

    2011-01-01

    Few empirical studies have directly explored the association between Buchnera aphidicola (Enterobacteriales: Enterobacteriaceae), the primary endosymbiont of aphids, and the life history strategies of aphid parasitoids. A series of paired-choice experiments were conducted to explore the preference of the parasitoid Lysiphlebus ambiguus Halliday (Hymenoptera: Aphididae) for symbiotic and aposymbiotic Aphis fabae Scopoli (Hemiptera: Aphididae) and the suitability of these hosts for parasitoid development. When given a choice between symbiotic and aposymbiotic aphids of the same instar, the parasitoid significantly preferred symbiotic over aposymbiotic aphids only during the later instars (L4 and adult). The suitability of aposymbiotic aphids for parasitoid development was equal to that of symbiotic aphids in terms of survivorship and sex ratio, but was significantly lower than that of symbiotic aphids for L4 and adult instars in development rate and/or female adult size. When given a choice between similar-sized symbiotic L2 and aposymbiotic L4 aphids, the parasitoid preferred the former. No significant differences in preference or host suitability were demonstrated when the parasitoid was given a choice between different instars of aposymbiotic aphids. While parasitoid lifetime fecundity increased with aphid instar at the time of oviposition, there was no significant influence of previous development from symbiotic versus aposymbiotic aphids. These results suggest that while L. ambiguus can discriminate between symbiotic and aposymbiotic A. fabae during later instars and when the aphids are of a similar size, the primary endosymbiont is not needed for successful parasitoid development; and its absence only compromises parasitoid growth reared from later instar aposymbiotic host. PMID:21870967

  9. Flapping Wing Micro Air Vehicle Wing Manufacture and Force Testing

    Science.gov (United States)

    2011-03-03

    manufacturing techniques have been developed by various universities for research on Flapping Wing Micro Air Vehicles. Minimal attention though is given...collected at 2kHz (www.polytec.com/psv3d). A 0.25V band-limited white noise input signal is input to a Bogen HTA -125 High Performance Amplifier, which...manufacturing techniques have been developed by various universities for research on Flapping Wing Micro Air Vehicles. Minimal attention though is given

  10. Aphids (Homoptera, Aphidodea inhabiting the trees Crataegus x media Bechst. in the urban green area. Part II. Domination and frequency of aphids, their enemies and the damage caused by aphids

    Directory of Open Access Journals (Sweden)

    Aneta Sławińska

    2013-12-01

    Full Text Available The studies were conducted in Lublin in the years 1999-2001 in two sites (street and park ones on the trees Crataegus x inedia Bechst. The purpose was to determine the domination and frequency of particular aphid species, their effect on the decorative character of plants as well as the occurrence of the aphidophagous in aphid colonies. It was found out that A. pomi was the dominating species in both sites. The decorative character of the studied trees was lowered by aphids A. pomi and aphids from the genus Dysaphis. Aphids from the genus Dysaphis also caused changes in the chemical composition of the injured plant parts. The presence of predatory arthropods was observed in aphid colonies occurring on hawthorn. The most numerous of these were the larvae of Syrphidae and Coccinellidae. The culture of parasitized aphids gave numerous flights of parasitoids and hyperparasitoids. Greater number of both predators and parasitoids of I and II grades were observed in the street site as compared to the park site.

  11. Ecological effects of aphid abundance, genotypic variation, and contemporary evolution on plants.

    Science.gov (United States)

    Turley, Nash E; Johnson, Marc T J

    2015-07-01

    Genetic variation and contemporary evolution within populations can shape the strength and nature of species interactions, but the relative importance of these forces compared to other ecological factors is unclear. We conducted a field experiment testing the effects of genotypic variation, abundance, and presence/absence of green peach aphids (Myzus persicae) on the growth, leaf nitrogen, and carbon of two plant species (Brassica napus and Solanum nigrum). Aphid genotype affected B. napus but not S. nigrum biomass explaining 20 and 7% of the total variation, respectively. Averaging across both plant species, the presence/absence of aphids had a 1.6× larger effect size (Cohen's d) than aphid genotype, and aphid abundance had the strongest negative effects on plant biomass explaining 29% of the total variation. On B. napus, aphid genotypes had different effects on leaf nitrogen depending on their abundance. Aphids did not influence leaf nitrogen in S. nigrum nor leaf carbon in either species. We conducted a second experiment in the field to test whether contemporary evolution could affect plant performance. Aphid populations evolved in as little as five generations, but the rate and direction of this evolution did not consistently vary between plant species. On one host species (B. napus), faster evolving populations had greater negative effects on host plant biomass, with aphid evolutionary rate explaining 23% of the variation in host plant biomass. Together, these results show that genetic variation and evolution in an insect herbivore can play important roles in shaping host plant ecology.

  12. Aphid secondary symbionts do not affect prey attractiveness to two species of predatory lady beetles.

    Directory of Open Access Journals (Sweden)

    Jennifer L Kovacs

    Full Text Available Heritable symbionts have been found to mediate interactions between host species and their natural enemies in a variety of organisms. Aphids, their facultative symbionts, and their potential fitness effects have been particularly well-studied. For example, the aphid facultative symbiont Regiella can protect its host from infection from a fungal pathogen, and aphids with Hamiltonella are less likely to be parasitized by parasitic wasps. Recent work has also found there to be negative fitness effects for the larvae of two species of aphidophagous lady beetles that consumed aphids with facultative symbionts. In both species, larvae that consumed aphids with secondary symbionts were significantly less likely to survive to adulthood. In this study we tested whether adult Harmonia axyridis and Hippodamia convergens lady beetles avoided aphids with symbionts in a series of choice experiments. Adults of both lady beetle species were as likely to choose aphids with symbionts as those without, despite the potential negative fitness effects associated with consuming aphids with facultative symbionts. This may suggest that under natural conditions aphid secondary symbionts are not a significant source of selection for predatory lady beetles.

  13. Aphid secondary symbionts do not affect prey attractiveness to two species of predatory lady beetles

    Science.gov (United States)

    Wolf, Candice; Voisin, Dené; Wolf, Seth

    2017-01-01

    Heritable symbionts have been found to mediate interactions between host species and their natural enemies in a variety of organisms. Aphids, their facultative symbionts, and their potential fitness effects have been particularly well-studied. For example, the aphid facultative symbiont Regiella can protect its host from infection from a fungal pathogen, and aphids with Hamiltonella are less likely to be parasitized by parasitic wasps. Recent work has also found there to be negative fitness effects for the larvae of two species of aphidophagous lady beetles that consumed aphids with facultative symbionts. In both species, larvae that consumed aphids with secondary symbionts were significantly less likely to survive to adulthood. In this study we tested whether adult Harmonia axyridis and Hippodamia convergens lady beetles avoided aphids with symbionts in a series of choice experiments. Adults of both lady beetle species were as likely to choose aphids with symbionts as those without, despite the potential negative fitness effects associated with consuming aphids with facultative symbionts. This may suggest that under natural conditions aphid secondary symbionts are not a significant source of selection for predatory lady beetles. PMID:28880922

  14. Aphid secondary symbionts do not affect prey attractiveness to two species of predatory lady beetles.

    Science.gov (United States)

    Kovacs, Jennifer L; Wolf, Candice; Voisin, Dené; Wolf, Seth

    2017-01-01

    Heritable symbionts have been found to mediate interactions between host species and their natural enemies in a variety of organisms. Aphids, their facultative symbionts, and their potential fitness effects have been particularly well-studied. For example, the aphid facultative symbiont Regiella can protect its host from infection from a fungal pathogen, and aphids with Hamiltonella are less likely to be parasitized by parasitic wasps. Recent work has also found there to be negative fitness effects for the larvae of two species of aphidophagous lady beetles that consumed aphids with facultative symbionts. In both species, larvae that consumed aphids with secondary symbionts were significantly less likely to survive to adulthood. In this study we tested whether adult Harmonia axyridis and Hippodamia convergens lady beetles avoided aphids with symbionts in a series of choice experiments. Adults of both lady beetle species were as likely to choose aphids with symbionts as those without, despite the potential negative fitness effects associated with consuming aphids with facultative symbionts. This may suggest that under natural conditions aphid secondary symbionts are not a significant source of selection for predatory lady beetles.

  15. Comparative transcriptomics and proteomics of three different aphid species identifies core and diverse effector sets.

    Science.gov (United States)

    Thorpe, Peter; Cock, Peter J A; Bos, Jorunn

    2016-03-02

    Aphids are phloem-feeding insects that cause significant economic losses to agriculture worldwide. While feeding and probing these insects deliver molecules, called effectors, inside their host to enable infestation. The identification and characterization of these effectors from different species that vary in their host range is an important step in understanding the infestation success of aphids and aphid host range variation. This study employs a multi-disciplinary approach based on transcriptome sequencing and proteomics to identify and compare effector candidates from the broad host range aphid Myzus persicae (green peach aphid) (genotypes O, J and F), and narrow host range aphids Myzus cerasi (black cherry aphid) and Rhopalosiphum padi (bird-cherry oat aphid). Using a combination of aphid transcriptome sequencing on libraries derived from head versus body tissues as well as saliva proteomics we were able to predict candidate effectors repertoires from the different aphid species and genotypes. Among the identified conserved or core effector sets, we identified a significant number of previously identified aphid candidate effectors indicating these proteins may be involved in general infestation strategies. Moreover, we identified aphid candidate effector sequences that were specific to one species, which are interesting candidates for further validation and characterization with regards to species-specific functions during infestation. We assessed our candidate effector repertoires for evidence of positive selection, and identified 49 candidates with DN/DS ratios >1. We noted higher rates of DN/DS ratios in predicted aphid effectors than non-effectors. Whether this reflects positive selection due to co-evolution with host plants, or increased neofunctionalization upon gene duplication remains to be investigated. Our work provides a comprehensive overview of the candidate effector repertoires from three different aphid species with varying host ranges

  16. First survey on ecological host range of aphid pathogenic fungi (Phylum Entomophthoromycota) in Tunisia

    DEFF Research Database (Denmark)

    Ben Fekih, Ibtissem; Boukhris-Bouhachem, Sonia; Allagui, Mohamed Bechir

    2015-01-01

    Summary. The natural occurrence of fungal pathogens of aphids and their ecological host range was investigated in Tunisia from 2009 to 2012. The survey focused on aphid infesting different crops and weeds and included 10 different aphid species. Samples were collected from eight agricultural crops...... C. obscurus and N. fresenii were sporadically present on a limited number of aphid species. This study is the first survey on ecological host range of entomophthoralean fungi in Tunisia, and the first documentation of C. obscurus and N. fresenii to occur in Tunisia and Maghreb Region....

  17. Bacteria may contribute to distant species recognition in ant-aphid mutualistic relationships.

    Science.gov (United States)

    Fischer, Christophe Y; Detrain, Claire; Thonart, Philippe; Haubruge, Eric; Francis, Frédéric; Verheggen, François J; Lognay, Georges C

    2017-04-01

    Mutualistic interactions between ant and aphid species have been the subject of considerable historical and contemporary investigations, the primary benefits being cleaning and protection for the aphids and carbohydrate-rich honeydew for the ants. Questions remained, however, as to the volatile semiochemical factor influencing this relationship. A recent study highlighted the role of bacterial honeydew volatile compounds in ant attraction. Here, ant's ability to distantly discriminate 2 aphid species was investigated based on bacterial honeydew semiochemicals emissions using a two-way olfactometer. Both the mutualistic aphid Aphis fabae L. and the nonmyrmecophilous aphid Acyrthosiphon pisum Harris were found to be attractive for the ant Lasius niger L. The level of attraction was similar in both assays (control vs. one of the aphid species). However, when given a choice between these 2 aphid species, ants showed a significant preference for Aphis fabae. Honeydew volatiles, mostly from bacterial origins, are known to be a key element in ant attraction. Using the same olfactometry protocol, the relative attractiveness of volatiles emitted by honeydews collected from each aphid species and by bacteria isolated from each honeydew was investigated. Again, ants significantly preferred volatiles released by Aphis fabae honeydew and bacteria. This information suggests that microbial honeydew volatiles enable ants to distantly discriminate aphid species. These results strengthen the interest of studying the occurrence and potential impact of microorganisms in insect symbioses. © 2015 Institute of Zoology, Chinese Academy of Sciences.

  18. A dietary test of putative deleterious sterols for the aphid Myzus persicae.

    Science.gov (United States)

    Bouvaine, Sophie; Faure, Marie-Line; Grebenok, Robert J; Behmer, Spencer T; Douglas, Angela E

    2014-01-01

    The aphid Myzus persicae displays high mortality on tobacco plants bearing a transgene which results in the accumulation of the ketosteroids cholestan-3-one and cholest-4-en-3-one in the phloem sap. To test whether the ketosteroids are the basis of the plant resistance to the aphids, M. persicae were reared on chemically-defined diets with different steroid contents at 0.1-10 µg ml(-1). Relative to sterol-free diet and dietary supplements of the two ketosteroids and two phytosterols, dietary cholesterol significantly extended aphid lifespan and increased fecundity at one or more dietary concentrations tested. Median lifespan was 50% lower on the diet supplemented with cholest-4-en-3-one than on the cholesterol-supplemented diet. Aphid feeding rate did not vary significantly across the treatments, indicative of no anti-feedant effect of any sterol/steroid. Aphids reared on diets containing equal amounts of cholesterol and cholest-4-en-3-one showed fecundity equivalent to aphids on diets containing only cholesterol. Aphids were reared on diets that reproduced the relative steroid abundance in the phloem sap of the control and modified tobacco plants, and their performance on the two diet formulations was broadly equivalent. We conclude that, at the concentrations tested, plant ketosteroids support weaker aphid performance than cholesterol, but do not cause acute toxicity to the aphids. In plants, the ketosteroids may act synergistically with plant factors absent from artificial diets but are unlikely to be solely responsible for resistance of modified tobacco plants.

  19. Chemical and physiological changes caused by aphids feeding on their host plants*

    Directory of Open Access Journals (Sweden)

    Cichocka Elżbieta

    2015-12-01

    Full Text Available We present significant information about damage caused to plants by the feeding of piercing–sucking insects, based on the example of aphids. Research concerning the impact of aphids on their host plants was already being carried out in the 1950s in the 20th century, but it is still being undertaken as it is very important. Aphid feeding causes deformation of plant tissues, disorders in plant metabolism and changes in the amount of various compounds in plant tissues. Plant viruses are transmitted in aphid saliva.

  20. New data on aphid fauna (Hemiptera, Aphididae) in Algeria

    Science.gov (United States)

    Laamari, Malik; d’Acier, Armelle Coeur; Jousselin, Emmanuelle

    2013-01-01

    Abstract A survey of aphids was carried out during the period 2008-2011 in different regions of Algeria by collecting and identifying aphids and their host plants. Aphids were collected from 46 host plants. Forty-six species were reported including thirty-six species which were recorded for the first time in this country and thirty species which were recorded for the first time in the Maghreb (North Africa). This study extends the number of known Algerian aphid to 156 species. PMID:24039520

  1. Coexistence of three specialist aphids on common milkweed, Asclepias syriaca.

    Science.gov (United States)

    Smith, R A; Mooney, K A; Agrawal, A A

    2008-08-01

    Coexistence of host-specific herbivores on plants is believed to be governed by interspecific interactions, but few empirical studies have systematically unraveled these dynamics. We investigated the role of several factors in promoting coexistence among the aphids Aphis nerii, Aphis asclepiadis, and Myzocallis asclepiadis that all specialize on common milkweed (Asclepias syriaca). Competitive exclusion is thought to occur when interspecific competition is stronger than intraspecific competition. Consequently, we investigated whether predators, mutualists, or resource quality affected the strength of intra- vs. interspecific competition among aphids in factorial manipulations of competition with exposure to predation, ants, and variable plant genotypes in three separate experiments. In the predation x competition experiment, predators reduced aphid per capita growth by 66%, but the strength of intra- and interspecific competition did not depend on predators. In the ants x competition experiment, ants reduced per capita growth of A. nerii and M. asclepiadis (neither of which were mutualists with ants) by approximately one-half. In so doing, ants ameliorated the negative effects of these competitors on ant-tended A. asclepiadis by two-thirds, representing a novel benefit of ant-aphid mutualism. Nevertheless, ants alone did not explain the persistence of competitively inferior A. asclepiadis as, even in the presence of ants, interspecific competition remained stronger than intraspecific competition. In the plant genotype x competition experiment, both A. asclepiadis and M. asclepiadis were competitively inferior to A. nerii, with the strength of interspecific competition exceeding that of intraspecific competition by 83% and 23%, respectively. Yet these effects differed among milkweed genotypes, and there were one or more plant genotypes for each aphid species where coexistence was predicted. A synthesis of our results shows that predators play little or no role in

  2. Robust Adaptive Neural Control of Morphing Aircraft with Prescribed Performance

    OpenAIRE

    Wu, Zhonghua; Lu, Jingchao; Shi, Jingping; Liu, Yang; Zhou, Qing

    2017-01-01

    This study proposes a low-computational composite adaptive neural control scheme for the longitudinal dynamics of a swept-back wing aircraft subject to parameter uncertainties. To efficiently release the constraint often existing in conventional neural designs, whose closed-loop stability analysis always necessitates that neural networks (NNs) be confined in the active regions, a smooth switching function is presented to conquer this issue. By integrating minimal learning parameter (MLP) tech...

  3. Wing morph-related differences in the walking pattern and dispersal in a flightless bug, Pyrrhocoris apterus (Heteroptera)

    Czech Academy of Sciences Publication Activity Database

    Socha, Radomír; Zemek, Rostislav

    2003-01-01

    Roč. 100, - (2003), s. 35-42 ISSN 0030-1299 R&D Projects: GA ČR GA206/99/0068 Institutional research plan: CEZ:AV0Z5007907 Keywords : L. Heteroptera * dimorphism * insects Subject RIV: ED - Physiology Impact factor: 2.142, year: 2003

  4. Endocrine control of wing morph-related differences in mating success and accessory gland size in male firebugs

    Czech Academy of Sciences Publication Activity Database

    Socha, Radomír

    2006-01-01

    Roč. 71, č. 6, (2006), s. 1273-1281 ISSN 0003-3472 R&D Projects: GA AV ČR(CZ) IAA6007301 Institutional research plan: CEZ:AV0Z50070508 Keywords : Pyrrhocoris apterus Subject RIV: ED - Physiology Impact factor: 2.711, year: 2006

  5. Actuator Placement Via Genetic Algorithm for Aircraft Morphing

    Science.gov (United States)

    Crossley, William A.; Cook, Andrea M.

    2001-01-01

    This research continued work that began under the support of NASA Grant NAG1-2119. The focus of this effort was to continue investigations of Genetic Algorithm (GA) approaches that could be used to solve an actuator placement problem by treating this as a discrete optimization problem. In these efforts, the actuators are assumed to be "smart" devices that change the aerodynamic shape of an aircraft wing to alter the flow past the wing, and, as a result, provide aerodynamic moments that could provide flight control. The earlier work investigated issued for the problem statement, developed the appropriate actuator modeling, recognized the importance of symmetry for this problem, modified the aerodynamic analysis routine for more efficient use with the genetic algorithm, and began a problem size study to measure the impact of increasing problem complexity. The research discussed in this final summary further investigated the problem statement to provide a "combined moment" problem statement to simultaneously address roll, pitch and yaw. Investigations of problem size using this new problem statement provided insight into performance of the GA as the number of possible actuator locations increased. Where previous investigations utilized a simple wing model to develop the GA approach for actuator placement, this research culminated with application of the GA approach to a high-altitude unmanned aerial vehicle concept to demonstrate that the approach is valid for an aircraft configuration.

  6. Evidence of indirect symbiont conferred protection against the predatory lady beetle Harmonia axyridis in the pea aphid.

    Science.gov (United States)

    Kovacs, Jennifer L; Wolf, Candice; Voisin, Dené; Wolf, Seth

    2017-07-11

    Defensive symbionts can provide significant fitness advantages to their hosts. Facultative symbionts can protect several species of aphid from fungal pathogens, heat shock, and parasitism by parasitoid wasps. Previous work found that two of these facultative symbionts can also indirectly protect pea aphids from predation by the lady beetle Hippocampus convergens. When aphids reproduce asexually, there is extremely high relatedness among aphid clone-mates and often very limited dispersal. Under these conditions, symbionts may indirectly protect aphid clone-mates from predation by negatively affecting the survival of a predator after the consumption of aphids harboring the same vertically transmitted facultative symbionts. In this study, we wanted to determine whether this indirect protection extended to another lady beetle species, Harmonia axyridis. We fed Ha. axyridis larvae aphids from one of four aphid sub-clonal symbiont lines which all originated from the same naturally symbiont free clonal aphid lineage. Three of the sub-clonal lines harbor different facultative symbionts that were introduced to the lines via microinjection. Therefore these sub-clonal lineages vary primarily in their symbiont composition, not their genetic background. We found that aphid facultative symbionts affected larval survival as well as pupal survival in their predator Ha. axyridis. Additionally, Ha. axyridis larvae fed aphids with the Regiella symbiont had significantly longer larval developmental times than beetle larvae fed other aphids, and females fed aphids with the Regiella symbiont as larvae weighed less as adults. These fitness effects were different from those previously found in another aphid predator Hi. convergens suggesting that the fitness effects may not be the same in different aphid predators. Overall, our findings suggest that some aphid symbionts may indirectly benefit their clonal aphid hosts by negatively impacting the development and survival of a lady beetle

  7. European species of the aphid genus Eulachnus Del Guercio, 1909 (Hemiptera: Aphididae: Lachninae): revision and molecular phylogeny.

    Science.gov (United States)

    Kanturski, Mariusz; Kajtoch, Łukasz; Wieczorek, Karina

    2017-11-27

    The aphid genus Eulachnus in Europe is revised to include 12 species, using an integrative taxonomy approach, based on morphometric, molecular and biological traits. Fundatrix, apterous and alate viviparous female of a new species-Eulachnus stekolshchikovi Kanturski sp. nov. are described. Neotypes are designated for E. agilis, E. brevipilosus and E. nigricola. Lectotypes are designated for E. alticola, E. cembrae, E. rileyi and E. tuberculostemmatus. New synonyms are proposed: E. abameleki syn. nov. (= Cinara pini), E. cretaceus syn. nov. (= E. agilis), E. tauricus syn. nov. (= E. rileyi), E. pallidus syn. nov. (= E. tuberculostemmatus). Eulachnus mingazzinii (near Cinara piniphila) and E. nigrofasciatus (near C. brauni) are regarded as incertae sedis. Full species status is given for E. garganicus stat. nov. and E. ibericus stat. nov. Apterous viviparous female of E. cembrae; apterous and alate viviparous females of remaining species are redescribed. Sexual morphs of E. agilis, E. alticola, E. cembrae, E. intermedius, E. nigricola, E. rileyi and oviparous female of E. tuberculostemmatus are fully redescribed and figured for the first time. Fundatrices of E. agilis, E. brevipilosus, E. cembrae, E. rileyi and E. tuberculostemmatus, sexuales of E. brevipilosus and the alate male of E. tuberculostemmatus are described and figured. A new host plant-Pinus cembra for E. brevipilosus is reported, and this species is recorded for the first time from Czech Republic. Eulachnus tuberculostemmatus is reported for the first time from Croatia. Phylogenetic studies, based on the COI and ITS2 molecular markers, are provided to visualize and discuss the relationships within the European species. COI barcodes are provided for seven species.

  8. Evidence of indirect symbiont conferred protection against the predatory lady beetle Harmonia axyridis in the pea aphid

    OpenAIRE

    Kovacs, Jennifer L.; Wolf, Candice; Voisin, Den?; Wolf, Seth

    2017-01-01

    Background Defensive symbionts can provide significant fitness advantages to their hosts. Facultative symbionts can protect several species of aphid from fungal pathogens, heat shock, and parasitism by parasitoid wasps. Previous work found that two of these facultative symbionts can also indirectly protect pea aphids from predation by the lady beetle Hippocampus convergens. When aphids reproduce asexually, there is extremely high relatedness among aphid clone-mates and often very limited disp...

  9. Effects of Entomopathogenic Nematodes on the Development of Root-knot Nematode and Aphid, and on the Parasitism of Aphid Parasitoid in Tobacco

    Directory of Open Access Journals (Sweden)

    WANG Yu-kun

    2017-05-01

    Full Text Available Entomopathogenic nematodes(EPN which is recognized as a kind of potential biological control material have been paid more and more attention in recent years. In the present study, we selected tobacco(Nicotiana tabacum as the object to study the effects of EPN (Steinernema carpocapsae and Heterorhabditis bacteriophoraon the development of root-knot nematodes and aphid (Myzus persicae, and on the parasitism of aphid parasitoid (Aphidius gifuensis in tobacco. The results showed that (1Under the condition of the artificial removal of aphids, the number of egg per plant was significantly lower under the EPN treatments than control treatment(PS. carpocapsae treatment than the other treatments(PH. bacteriophora cadaver treatment were 89.6 individual·plant-1 and 0.996 g·plant-1, 99.8 individual·plant-1 and 3.258 g·plant-1, 76.6 individual·plant-1 and 1.643 g·plant-1, respectively, indicating that EPN treatment could decrease the number of aphids per mass; (3On the first three observation dates, the number of aphid mummies was significantly lower under S. carpocapsae cadaver treatment than H. bacteriophora cadaver treatment. The results indicated that EPN treatments in tobacco could affect the development of root-knot nematode, and had impact on the development of aphids and the activities of aphid parasitoid by "bottom-up" approach, and these effects were affected by the species of EPN.

  10. Oral activity of FMRFamide-related peptides on the pea aphid Acyrthosiphon pisum (Hemiptera: Aphididae) and degradation by enzymes from the aphid gut.

    Science.gov (United States)

    Down, Rachel E; Matthews, H June; Audsley, Neil

    2011-11-10

    Insect myosuppressins and myosuppressin analogues were tested for oral toxicity against the pea aphid Acyrthosiphon pisum (Harris) by incorporation into an artificial diet. Acyrthosiphon pisum myosuppressin (Acypi-MS) and leucomyosuppressin (LMS) had significant dose-dependent effects (0.1-0.5μg peptide/μl diet) on feeding suppression, mortality, reduced growth and fecundity compared with control insects, but Acypi-MS was more potent than LMS. One hundred percent of aphids had died after 10days of feeding on 0.5μg Acypi-MS/μl diet whereas 40% of aphids feeding on 0.5μg LMS/μl diet were still alive after 13days. Myosuppressins were degraded by aphid gut enzymes; degradation was most likely due to a carboxypeptidase-like protease, an aminopeptidase and a cathepsin L cysteine protease. The estimated half-life of Acypi-MS in a gut extract was 30min, whereas LMS was degraded more slowly (t½=54min). No toxicity was observed when the analogues δR(9) LMS and citrolline(9) Acypi-MS or FMRFamide were fed to the pea aphid. These findings not only help to better understand the biological effects of myosuppressins in aphids but also demonstrate the potential use of myosuppressins in a strategy to control aphid pests. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

  11. Morphing continuum analysis of energy transfer in compressible turbulence

    Science.gov (United States)

    Cheikh, Mohamad Ibrahim; Wonnell, Louis B.; Chen, James

    2018-02-01

    A shock-preserving finite volume solver with the generalized Lax-Friedrichs splitting flux for morphing continuum theory (MCT) is presented and verified. The numerical MCT solver is showcased in a supersonic turbulent flow with Mach 2.93 over an 8∘ compression ramp. The simulation results validated MCT with experiments as an alternative for modeling compressible turbulence. The required size of the smallest mesh cell for the MCT simulation is shown to be almost an order larger than that in a similar direct numerical simulation study. The comparison shows MCT is a much more computationally friendly theory than the classical Navier-Stokes equations. The dynamics of energy cascade at the length scale of individual eddies is illuminated through the subscale rotation introduced by MCT. In this regard, MCT provides a statistical averaging procedure for capturing energy transfer in compressible turbulence, not found in classical fluid theories. Analysis of the MCT results show the existence of a statistical coupling of the internal and translational kinetic energy fluctuations with the corresponding eddy rotational energy fluctuations, indicating a multiscale transfer of energy. In conclusion, MCT gives a new characterization of the energy cascade within compressible turbulence without the use of excessive computational resources.

  12. 4D Biofabrication Using Shape-Morphing Hydrogels.

    Science.gov (United States)

    Kirillova, Alina; Maxson, Ridge; Stoychev, Georgi; Gomillion, Cheryl T; Ionov, Leonid

    2017-12-01

    Despite the tremendous potential of bioprinting techniques toward the fabrication of highly complex biological structures and the flourishing progress in 3D bioprinting, the most critical challenge of the current approaches is the printing of hollow tubular structures. In this work, an advanced 4D biofabrication approach, based on printing of shape-morphing biopolymer hydrogels, is developed for the fabrication of hollow self-folding tubes with unprecedented control over their diameters and architectures at high resolution. The versatility of the approach is demonstrated by employing two different biopolymers (alginate and hyaluronic acid) and mouse bone marrow stromal cells. Harnessing the printing and postprinting parameters allows attaining average internal tube diameters as low as 20 µm, which is not yet achievable by other existing bioprinting/biofabrication approaches and is comparable to the diameters of the smallest blood vessels. The proposed 4D biofabrication process does not pose any negative effect on the viability of the printed cells, and the self-folded hydrogel-based tubes support cell survival for at least 7 d without any decrease in cell viability. Consequently, the presented 4D biofabrication strategy allows the production of dynamically reconfigurable architectures with tunable functionality and responsiveness, governed by the selection of suitable materials and cells. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Dynamic masquerade with morphing three-dimensional skin in cuttlefish.

    Science.gov (United States)

    Panetta, Deanna; Buresch, Kendra; Hanlon, Roger T

    2017-03-01

    Masquerade is a defence tactic in which a prey resembles an inedible or inanimate object thus causing predators to misclassify it. Most masquerade colour patterns are static although some species adopt postures or behaviours to enhance the effect. Dynamic masquerade in which the colour pattern can be changed is rare. Here we report a two-step sensory process that enables an additional novel capability known only in cuttlefish and octopus: morphing three-dimensional physical skin texture that further enhances the optical illusions created by coloured skin patterns. Our experimental design incorporated sequential sensory processes: addition of a three-dimensional rock to the testing arena, which attracted the cuttlefish to settle next to it; then visual processing by the cuttlefish of physical textures on the rock to guide expression of the skin papillae, which can range from fully relaxed (smooth skin) to fully expressed (bumpy skin). When a uniformly white smooth rock was presented, cuttlefish moved to the rock and deployed a uniform body pattern with mostly smooth skin. When a rock with small-scale fragments of contrasting shells was presented, the cuttlefish deployed mottled body patterns with strong papillae expression. These robust and reversible responses indicate a sophisticated visual sensorimotor system for dynamic masquerade. © 2017 The Author(s).

  14. Morphing continuum theory for turbulence: Theory, computation, and visualization

    Science.gov (United States)

    Chen, James

    2017-10-01

    A high order morphing continuum theory (MCT) is introduced to model highly compressible turbulence. The theory is formulated under the rigorous framework of rational continuum mechanics. A set of linear constitutive equations and balance laws are deduced and presented from the Coleman-Noll procedure and Onsager's reciprocal relations. The governing equations are then arranged in conservation form and solved through the finite volume method with a second-order Lax-Friedrichs scheme for shock preservation. A numerical example of transonic flow over a three-dimensional bump is presented using MCT and the finite volume method. The comparison shows that MCT-based direct numerical simulation (DNS) provides a better prediction than Navier-Stokes (NS)-based DNS with less than 10% of the mesh number when compared with experiments. A MCT-based and frame-indifferent Q criterion is also derived to show the coherent eddy structure of the downstream turbulence in the numerical example. It should be emphasized that unlike the NS-based Q criterion, the MCT-based Q criterion is objective without the limitation of Galilean invariance.

  15. The morphing properties of a vascular shape memory composite

    International Nuclear Information System (INIS)

    Cortes, P; Kubas, G; Terzak, J; Phillips, D; Baur, J W

    2014-01-01

    This work investigates the fabrication, experimentation, testing, and modeling of shape memory composites consisting of two-way shape memory alloy (SMA) tubes embedded in a shape memory polymer (SMP) matrix. The hybrid system here investigated is thermally activated via internal transport of thermal fluids through the SMA vascular system. The resulting shape memory composite (SMC) combines the high modulus and high specific actuation force of SMAs with the strong shape fixing and variable stiffness of SMPs to create a light-weight composite capable of controllably and rapidly achieving two shape memory states. Specifically, a 25° thermally induced out-of-plane bending state is achieved with a 2% volume fraction of SMA in the composite after 2 min of being activated by an internal thermal fluid. Here, while the thermal structural design of the SMC was not optimized and the thermal cycling was significantly restricted by the low thermal conduction of the SMP, the deflection of the composite was within 20% of the expected value modeled by the thermal–mechanical finite element analysis (FEA) here performed. The close agreement between the experimental performance and the modeled composite response suggests that morphing composites based on SMAs and SMPs are promising structures for adaptive applications. (paper)

  16. Flow control at low Reynolds numbers using periodic airfoil morphing

    Science.gov (United States)

    Jones, Gareth; Santer, Matthew; Papadakis, George; Bouremel, Yann; Debiasi, Marco; Imperial-NUS Joint PhD Collaboration

    2014-11-01

    The performance of airfoils operating at low Reynolds numbers is known to suffer from flow separation even at low angles of attack as a result of their boundary layers remaining laminar. The lack of mixing---a characteristic of turbulent boundary layers---leaves laminar boundary layers with insufficient energy to overcome the adverse pressure gradient that occurs in the pressure recovery region. This study looks at periodic surface morphing as an active flow control technique for airfoils in such a flight regime. It was discovered that at sufficiently high frequencies an oscillating surface is capable of not only reducing the size of the separated region---and consequently significantly reducing drag whilst simultaneously increasing lift---but it is also capable of delaying stall and as a result increasing CLmax. Furthermore, by bonding Macro Fiber Composite actuators (MFCs) to the underside of an airfoil skin and driving them with a sinusoidal frequency, it is shown that this control technique can be practically implemented in a lightweight, energy efficient way. Imperial-NUS Joint Ph.D. Programme.

  17. Morphing of Bistable Composite Laminates Using Distributed Piezoelectric Actuators

    Directory of Open Access Journals (Sweden)

    Marie-Laure Dano

    2012-01-01

    Full Text Available The use of bistable unsymmetric cross-ply laminates for morphing application has received growing attention in the last few years. So far, most studies use large rectangular piezoelectric Macro Fiber Composite (MFC patches bonded at the center of the laminate to induce snap-through. However, the use of large rectangular MFC patches bonded in the center of the laminates significantly influences the shape of the laminate by greatly reducing the curvature at the midsection of the laminate where the MFC patches are bonded. This paper presents a study where narrow cocured MFC strips distributed over the entire surface are used to induce snap-through of unsymmetric cross-ply laminates. This MFC configuration allows having a more uniform curvature in the laminate. Since the strips are bonded on both sides, reverse snap-through should be obtained. The study was both theoretical and experimental. A finite element nonlinear analysis was used to predict the two stable cylindrical configurations and the snap-through induced by MFC actuation. For the experimental study, a laminate-MFC structure was manufactured and tested. The shapes were measured using a 3D image correlation system as a function of applied voltage. Good correlations for the cylindrical shape and displacement field were observed.

  18. Soybean aphid (Hemiptera: Aphididae) response to soybean plant defense: stress levels, tradeoffs, and cross-virulence.

    Science.gov (United States)

    Enders, Laramy; Bickel, Ryan; Brisson, Jennifer; Heng-Moss, Tiffany; Siegfried, Blair; Zera, Anthony; Miller, Nick

    2014-02-01

    A variety of management methods to control the soybean aphid (Aphis glycines Matsumura) have been investigated since its invasion into North America in 2000, among them plant resistance has emerged as a viable option for reducing aphid damage to soybeans and preventing outbreaks. Plant resistance methods often use natural soybean plant defenses that impose stress on aphids by reducing fitness and altering behavior. Research efforts have heavily focused on identification and development of aphid resistant soybean varieties, leaving much unknown about soybean aphid response to stressful host plant defenses. In this study, we aimed to 1) evaluate lifetime fitness consequences and phenotypic variation in response to host plant-induced stress and 2) investigate whether trade-offs involving fitness costs and/or cross-virulence to multiple antibiotic soybean varieties exists. We compared aphid survival and reproduction during and after a short period of exposure to soybeans with the Rag2 resistance gene and measured aphid clonal variation in response to Rag2 soybeans. In addition, we measured the performance of Rag2 virulent and avirulent aphids on five soybean varieties with various forms of antibiotic resistance. Our results indicate that plant defenses impose high levels of stress and have long-term fitness consequences, even after aphids are removed from resistant plants. We identified one aphid clone that was able to colonize Rag2 among the seven clones tested, suggesting that virulent genotypes may be prevalent in natural populations. Finally, although we did not find evidence of cross-virulence to multiple antibiotic soybean varieties, our results suggest independent mechanisms of aphid virulence to Rag1 and Rag2 that may involve fitness costs.

  19. Indian Bt Cotton Varieties Do Not Affect the Performance of Cotton Aphids

    Science.gov (United States)

    Lawo, Nora C.; Wäckers, Felix L.; Romeis, Jörg

    2009-01-01

    Cotton varieties expressing Cry proteins derived from the soil bacterium Bacillus thuringiensis (Bt) are grown worldwide for the management of pest Lepidoptera. To prevent non-target pest outbreaks and to retain the biological control function provided by predators and parasitoids, the potential risk that Bt crops may pose to non-target arthropods is addressed prior to their commercialization. Aphids play an important role in agricultural systems since they serve as prey or host to a number of predators and parasitoids and their honeydew is an important energy source for several arthropods. To explore possible indirect effects of Bt crops we here examined the impact of Bt cotton on aphids and their honeydew. In climate chambers we assessed the performance of cotton aphids, Aphis gossypii Glover (Hemiptera: Aphididae) when grown on three Indian Bt (Cry1Ac) cotton varieties (MECH 12, MECH 162, MECH 184) and their non-transformed near isolines. Furthermore, we examined whether aphids pick up the Bt protein and analyzed the sugar composition of aphid honeydew to evaluate its suitability for honeydew-feeders. Plant transformation did not have any influence on aphid performance. However, some variation was observed among the three cotton varieties which might partly be explained by the variation in trichome density. None of the aphid samples contained Bt protein. As a consequence, natural enemies that feed on aphids are not exposed to the Cry protein. A significant difference in the sugar composition of aphid honeydew was detected among cotton varieties as well as between transformed and non-transformed plants. However, it is questionable if this variation is of ecological relevance, especially as honeydew is not the only sugar source parasitoids feed on in cotton fields. Our study allows the conclusion that Bt cotton poses a negligible risk for aphid antagonists and that aphids should remain under natural control in Bt cotton fields. PMID:19279684

  20. Plant genetic variation mediates an indirect ecological effect between belowground earthworms and aboveground aphids.

    Science.gov (United States)

    Singh, Akanksha; Braun, Julia; Decker, Emilia; Hans, Sarah; Wagner, Agnes; Weisser, Wolfgang W; Zytynska, Sharon E

    2014-10-21

    Interactions between aboveground and belowground terrestrial communities are often mediated by plants, with soil organisms interacting via the roots and aboveground organisms via the shoots and leaves. Many studies now show that plant genetics can drive changes in the structure of both above and belowground communities; however, the role of plant genetic variation in mediating aboveground-belowground interactions is still unclear. We used an earthworm-plant-aphid model system with two aphid species (Aphis fabae and Acyrthosiphon pisum) to test the effect of host-plant (Vicia faba) genetic variation on the indirect interaction between the belowground earthworms (Eisenia veneta) on the aboveground aphid populations. Our data shows that host-plant variety mediated an indirect ecological effect of earthworms on generalist black bean aphids (A. fabae), with earthworms increasing aphid growth rate in three plant varieties but decreasing it in another variety. We found no effect of earthworms on the second aphid species, the pea aphid (A. pisum), and no effect of competition between the aphid species. Plant biomass was increased when earthworms were present, and decreased when A. pisum was feeding on the plant (mediated by plant variety). Although A. fabae aphids were influenced by the plants and worms, they did not, in turn, alter plant biomass. Previous work has shown inconsistent effects of earthworms on aphids, but we suggest these differences could be explained by plant genetic variation and variation among aphid species. This study demonstrates that the outcome of belowground-aboveground interactions can be mediated by genetic variation in the host-plant, but depends on the identity of the species involved.